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Sample records for dendrimer-like polyethylene oxides

  1. High-efficiency synthesis of dendrimer-like poly(ethylene oxide) via “arm-first” approach

    KAUST Repository

    Zhu, Saisai

    2017-04-14

    In this study, a dendrimer-like polymer based on poly(ethylene oxide) (PEO) was synthesized through a combination of anionic ring-opening polymerization (AROP) and click reaction via arm-first method. Firstly, the polymeric arm, a linear PEO with one alkynyl group and two bromo groups, was synthesized by AROP of ethylene oxide followed by functionalization with propargyl bromide and esterified with 2-bromopropionic bromide. Second, a star PEO carrying three azide groups was synthesized though AROP of ethylene oxide used 1,1,1-tris(hydrosymethyl) ethane as initiator followed esterificated with 2-bromopropionic acid and azidation. By azide–alkyne click reactions between the azide-terminated PEO star polymer and linear PEO with functionalization alkynyl group, a three generation dendrimer-like PEO, G3-PEO-24Br, was successfully synthesized. The resulting polymers were observed to have precisely controlled molecular weights and compositions with narrow molecular weight distributions.

  2. Synthesis of an amphiphilic dendrimer-like block copolymer and its application on drug delivery

    KAUST Repository

    Wang, Shuaipeng

    2014-10-27

    Dendrimer-like amphiphilic copolymer is a kind of three-dimensional spherical structure polymer. An amphiphilic dendrimer-like diblock copolymer, PEEGE-G2-b-PEO(OH)12, constituted of a hydrophobic poly(ethoxyethyl glycidol ether) inner core and a hydrophilic poly(ethylene oxide) outer layer, has been successfully synthesized by the living anionic ring-opening polymerization method. The intermediates and targeted products were characterized with 1H NMR spectroscopy and gel permeation chromatography. The application on drug delivery of dendrimer-like diblock copolymer PEEGE-G2-b-PEO(OH)12 using DOX as a model drug was also studied. The drug loading content and encapsulation efficiency were found at 13.07% and 45.75%, respectively. In vitro release experiment results indicated that the drug-loaded micelles exhibited a sustained release behavior under acidic media.

  3. Poly(ethylene oxide) functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, Russell Clayton

    2014-04-08

    A simple procedure is provided by which the hydroxyl termini of poly(ethylene oxide) can be appended with functional groups to a useful extent by reaction and precipitation. The polymer is dissolved in warmed toluene, treated with an excess of organic base and somewhat less of an excess of a reactive acylating reagent, reacted for several hours, then precipitated in isopropanol so that the product can be isolated as a solid, and salt byproducts are washed away. This procedure enables functionalization of the polymer while not requiring laborious purification steps such as solvent-solvent extraction or dialysis to remove undesirable side products.

  4. Controlled doping by self-assembled dendrimer-like macromolecules.

    Science.gov (United States)

    Wu, Haigang; Guan, Bin; Sun, Yingri; Zhu, Yiping; Dan, Yaping

    2017-02-01

    Doping via self-assembled macromolecules might offer a solution for developing single atom electronics by precisely placing individual dopants at arbitrary location to meet the requirement for circuit design. Here we synthesize dendrimer-like polyglycerol macromolecules with each carrying one phosphorus atom in the core. The macromolecules are immobilized by the coupling reagent onto silicon surfaces that are pre-modified with a monolayer of undecylenic acid. Nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) are employed to characterize the synthesized macromolecules and the modified silicon surfaces, respectively. After rapid thermal annealing, the phosphorus atoms carried by the macromolecules diffuse into the silicon substrate, forming dopants at a concentration of 10(17) cm(-3). Low-temperature Hall effect measurements reveal that the ionization process is rather complicated. Unlike the widely reported simple ionization of phosphorus dopants, nitrogen and carbon are also involved in the electronic activities in the monolayer doped silicon.

  5. Controlled doping by self-assembled dendrimer-like macromolecules

    Science.gov (United States)

    Wu, Haigang; Guan, Bin; Sun, Yingri; Zhu, Yiping; Dan, Yaping

    2017-02-01

    Doping via self-assembled macromolecules might offer a solution for developing single atom electronics by precisely placing individual dopants at arbitrary location to meet the requirement for circuit design. Here we synthesize dendrimer-like polyglycerol macromolecules with each carrying one phosphorus atom in the core. The macromolecules are immobilized by the coupling reagent onto silicon surfaces that are pre-modified with a monolayer of undecylenic acid. Nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) are employed to characterize the synthesized macromolecules and the modified silicon surfaces, respectively. After rapid thermal annealing, the phosphorus atoms carried by the macromolecules diffuse into the silicon substrate, forming dopants at a concentration of 1017 cm‑3. Low-temperature Hall effect measurements reveal that the ionization process is rather complicated. Unlike the widely reported simple ionization of phosphorus dopants, nitrogen and carbon are also involved in the electronic activities in the monolayer doped silicon.

  6. Hydrophilic poly(ethylene oxide)-aramide segmented block copolymers

    NARCIS (Netherlands)

    Araichimani, A.; ten Hoopen, Hermina W.M.; Gaymans, R.J.

    2009-01-01

    The present paper discusses block copolymers with segments of either poly(ethylene oxide), poly(propylene oxide), or mixtures of poly(ethylene oxide)/poly(propylene oxide) and monodisperse aramide segments. The length of the polyether segments as well as the concentration of polyethylene oxide was

  7. Dendrimer-like hybrid particles with tunable hierarchical pores

    Science.gov (United States)

    Du, Xin; Li, Xiaoyu; Huang, Hongwei; He, Junhui; Zhang, Xueji

    2015-03-01

    Dendrimer-like silica particles with a center-radial dendritic framework and a synergistic hierarchical porosity have attracted much attention due to their unique open three-dimensional superstructures with high accessibility to the internal surface areas; however, the delicate regulation of the hierarchical porosity has been difficult to achieve up to now. Herein, a series of dendrimer-like amino-functionalized silica particles with tunable hierarchical pores (HPSNs-NH2) were successfully fabricated by carefully regulating and optimizing the various experimental parameters in the ethyl ether emulsion systems via a one-pot sol-gel reaction. Interestingly, the simple adjustment of the stirring rate or reaction temperature was found to be an easy and effective route to achieve the controllable regulation towards center-radial large pore sizes from ca. 37-267 (148 +/- 45) nm to ca. 8-119 (36 +/- 21) nm for HPSNs-NH2 with particle sizes of 300-700 nm and from ca. 9-157 (52 +/- 28) nm to ca. 8-105 (30 +/- 16) nm for HPSNs-NH2 with particle sizes of 100-320 nm. To the best of our knowledge, this is the first successful regulation towards center-radial large pore sizes in such large ranges. The formation of HPSNs-NH2 may be attributed to the complex cross-coupling of two processes: the dynamic diffusion of ethyl ether molecules and the self-assembly of partially hydrolyzed TEOS species and CTAB molecules at the dynamic ethyl ether-water interface of uniform small quasi-emulsion droplets. Thus, these results regarding the elaborate regulation of center-radial large pores and particle sizes not only help us better understand the complicated self-assembly at the dynamic oil-water interface, but also provide a unique and ideal platform as carriers or supports for adsorption, separation, catalysis, biomedicine, and sensor.Dendrimer-like silica particles with a center-radial dendritic framework and a synergistic hierarchical porosity have attracted much attention due to their

  8. A thermoelectric voltage effect in polyethylene oxide

    CERN Document Server

    Martin, B; Kliem, H

    2003-01-01

    The conductivity of polyethylene oxide (PEO) is described with a three-dimensional hopping model considering electrostatic interactions between the ions. Ions fluctuate over energy-barriers in a multi-well potential. To decide whether positive or negative charges are responsible for this conductivity, the thermoelectric voltage is measured. The samples are embedded between two aluminium-electrodes. The oxide on the interface between the electrodes and the PEO serves as a blocking layer. The temperature of each electrode is controlled by a Peltier element. A temperature step is applied to one electrode by changing the temperature of one of the Peltier elements. Due to this temperature gradient, the mobile charges fluctuate thermally activated from the warmer side to the colder side of the sample. The direction of the measured thermoelectric voltage indicates the type of mobile charges. It is found that positive charges are mobile. Further, it is shown that the absolute value of the thermoelectric voltage depen...

  9. A Coarse-Grained Model for Polyethylene Oxide and Polyethylene Glycol : Conformation and Hydrodynamics

    NARCIS (Netherlands)

    Lee, Hwankyu; de Vries, Alex H.; Marrink, Siewert-Jan; Pastor, Richard W.

    2009-01-01

    A coarse-grained (CG) model for polyethylene oxide (PEO) and polyethylene glycol (PEG) developed within the framework of the MARTINI CG force field (FF) using the distributions of bonds, angles, and dihedrals from the CHARMM all-atom FF is presented. Densities of neat low molecular weight PEO agree

  10. A Coarse-Grained Model for Polyethylene Oxide and Polyethylene Glycol : Conformation and Hydrodynamics

    NARCIS (Netherlands)

    Lee, Hwankyu; de Vries, Alex H.; Marrink, Siewert-Jan; Pastor, Richard W.

    2009-01-01

    A coarse-grained (CG) model for polyethylene oxide (PEO) and polyethylene glycol (PEG) developed within the framework of the MARTINI CG force field (FF) using the distributions of bonds, angles, and dihedrals from the CHARMM all-atom FF is presented. Densities of neat low molecular weight PEO agree

  11. Polyethylene oxide hydration in grafted layers

    Science.gov (United States)

    Dormidontova, Elena; Wang, Zilu

    Hydration of water soluble polymers is one of the key-factors defining their conformation and properties, similar to biopolymers. Polyethylene oxide (PEO) is one of the most important biomedical-applications polymers and is known for its reverse temperature solubility due to hydrogen bonding with water. As in many practical applications PEO chains are grafted to surfaces, e.g. of nanoparticles or planar surfaces, it is important to understand PEO hydration in such grafted layers. Using atomistic molecular dynamic simulations we investigate the details of molecular conformation and hydration of PEO end-grafted to gold surfaces. We analyze polymer and water density distribution as a function of distance from the surface for different grafting densities. Based on a detailed analysis of hydrogen bonding between polymer and water in grafted PEO layers, we will discuss the extent of PEO hydration and its implication for polymer conformation, mobility and layer properties. This research is supported by NSF (DMR-1410928).

  12. Versatile ferrofluids based on polyethylene glycol coated iron oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Brullot, W., E-mail: ward.brullot@fys.kuleuven.be [Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200D, 3001 Heverlee, Leuven (Belgium); Reddy, N.K. [Department of Chemical Engineering, Katholieke Universiteit Leuven, Willem de Croylaan 46, 3001 Heverlee, Leuven (Belgium); Wouters, J.; Valev, V.K.; Goderis, B. [Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200D, 3001 Heverlee, Leuven (Belgium); Vermant, J. [Department of Chemical Engineering, Katholieke Universiteit Leuven, Willem de Croylaan 46, 3001 Heverlee, Leuven (Belgium); Verbiest, T. [Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200D, 3001 Heverlee, Leuven (Belgium)

    2012-06-15

    Versatile ferrofluids based on polyethylene glycol coated iron oxide nanoparticles were obtained by a facile protocol and thoroughly characterized. Superparamagnetic iron oxide nanoparticles synthesized using a modified forced hydrolysis method were functionalized with polyethylene glycol silane (PEG silane), precipitated and dried. These functionalized particles are dispersable in a range of solvents and concentrations depending on the desired properties. Examples of tunable properties are magnetic behavior, optical and magneto-optical response, thermal features and rheological behavior. As such, PEG silane functionalized particles represent a platform for the development of new materials that have broad applicability in e.g. biomedical, industrial or photonic environments. Magnetic, optical, magneto-optical, thermal and rheological properties of several ferrofluids based on PEG coated particles with different concentrations of particles dispersed in low molecular mass polyethylene glycol were investigated, establishing the applicability of such materials. - Highlights: Black-Right-Pointing-Pointer Ferrofluids based on polyethylene glycol coated iron oxide nanoparticles. Black-Right-Pointing-Pointer Magnetic, optical, magneto-optical, thermal and rheological characterization of ferrofluids. Black-Right-Pointing-Pointer Tunable properties of versatile polyethylene glycol stabilized ferrofluids.

  13. Synthesis and In Vitro Cancer Cell Targeting of Folate-Functionalized Biodegradable Amphiphilic Dendrimer-Like Star Polymers

    NARCIS (Netherlands)

    Cao, Weiqiang; Zhou, Jing; Wang, Yong; Zhu, Lei

    2010-01-01

    By coupling a well-defined PLLA star polymer with six carboxylic acid-terminated polyester dendrons based on 2,2-bis(hydroxymethyl)propionic acid, a biodegradable dendrimer-like star polymer (DLSP) with multiple carboxylic acid groups at the outer surface was successfully synthesized. Conjugation of

  14. Dendrimer-like assemblies based on organoclays as multi-host system for sustained drug delivery.

    Science.gov (United States)

    Li, Wei; Sun, Lili; Pan, Lijun; Lan, Zuopin; Jiang, Tao; Yang, Xiaolan; Luo, Jianchun; Li, Ronghua; Tan, Liqing; Zhang, Shurong; Yu, Mingan

    2014-11-01

    Chemical modification of nanoclay will ensure further progress on these materials. In this work, we show that montmorillonite (MTM) nanosheets can be modified with β-cyclodextrin (CD) via a nucleophilic substitution reaction between mono-6-(p-toluenesulfonyl)-6-deoxy-β-CD and an amino group of 3-aminopropyltriethoxysilane (APTES)-functionalized MTM. The resulting MTM-APTES-CD can be further self-assembled into dendrimer-like assemblies, exhibit a well-dispersed property even in Dulbecco's phosphate-buffered saline and do not aggregate for a period of at least 20days. The structure, morphology and assembly mechanism are systematically studied by (29)Si MAS NMR, FT-IR, (1)H NMR, SEM, FE-TEM, DLS and AFM, and the change in assemblies during the drug release is monitored using FE-TEM images. MTT assays indicate that the assemblies only have low cytotoxicity, while CLSM and TEM observations reveal that the assemblies can easily penetrate cultured human endothelial cells. When clopidogrel is used as a guest molecule, the assemblies show not only much higher loading capacities compared to MTM and other containing β-CD assemblies or nanoparticles, but also a sustained release of clopidogrel up to 30days. This is attributed to the fact that the guest molecule is both supramolecularly complexed within the dendritic scaffold and intercalated into CD and MTM hosts. Host-guest systems between assemblies and various guests hold promising applications in drug delivery system and in the biomedical fields.

  15. Dendrimer-like alpha-d-glucan nanoparticles activate dendritic cells and are effective vaccine adjuvants.

    Science.gov (United States)

    Lu, Fangjia; Mencia, Alejandra; Bi, Lin; Taylor, Aaron; Yao, Yuan; HogenEsch, Harm

    2015-04-28

    The use of nanoparticles for delivery of vaccine antigens and as vaccine adjuvants is appealing because their size allows efficient uptake by dendritic cells and their biological properties can be tailored to the desired function. Here, we report the effect of chemically modified phytoglycogen, a dendrimer-like α-d-glucan nanoparticle, on dendritic cells in vitro, and the utility of this type of nanoparticle as a vaccine adjuvant in vivo. The modified phytoglycogen nanoparticle, termed Nano-11, has a positive surface charge which enabled electrostatic adsorption of negatively charged protein antigens. The Nano-11-antigen complexes were efficiently phagocytized by dendritic cells. Nano-11 induced increased expression of costimulatory molecules and the secretion of IL-1β and IL-12p40 by dendritic cells. Intramuscular injection of Nano-11-antigen formulations induced a significantly enhanced immune response to two different protein antigens. Examination of the injection site revealed numerous monocytes and relatively few neutrophils at one day after injection. The inflammation had nearly completely disappeared by 2 weeks after injection. These studies indicate that Nano-11 is an effective vaccine delivery vehicle that significantly enhances the immune response. This type of plant based nanoparticle is considered highly cost-effective compared with fully synthetic nanoparticles and appears to have an excellent safety profile making them an attractive adjuvant candidate for prophylactic vaccines.

  16. Novel Dendrimer-Like Star Copolymer Architectures Investigated with Scattering Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Pople, John A

    2001-10-17

    Hyperbranched dendrimer molecules emanating from a central core were successfully synthesized just over a decade ago and have been gaining the interest of polymer scientists due to their unique properties and promising applications. Several groups have sought structural and dynamic information on dendrimeric molecules with some degree of success. Most of the studies thus far have focused on dendrimeric structures having relatively short links between branching points and having a uniform distribution of branches throughout the molecule. We are interested in dendrimer-star molecules where polymer chains connect the branch points and the length and placement of these chains can be varied systematically. We have taken one approach to such systems by investigating a series of constitutional isomers having the same molecular weight and number of branch points and surface functionalities, but varied branch placement to alter the architecture. In this way, we can study the influence of the architecture on the structure, interactions, and dynamics of these molecules. to provide neutron scattering contrast. The PCL dendrimer-like stars then comprise the cores of the molecules while the PMMA chains emanate from the periphery. The samples used in the scattering experiments were prepared in either THF or toluene, which are both good solvents for PCL and PMMA, to mass fractions of 0.2 wt% to 30 wt%.

  17. Processable conductive graphene/polyethylene nanocomposites: Effects of graphene dispersion and polyethylene blending with oxidized polyethylene on rheology and microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad Z.; Abdala, Ahmed A.; Mittal, Vikas; Seifert, Sӧnke; Herring, Andrew M.; Liberatore, Matthew W.

    2016-08-01

    Poor dispersion of graphene in non-polar polymer matrices creates composites with limited applications. A method to improve the dispersion of graphene in polyethylene (PE) via blending PE with oxidized PE (OPE) is examined. Graphene was produced by simultaneous thermal exfoliation and reduction of graphite oxide. Nanocomposites of graphene with PE as well as graphene with PE/OPE-blends were prepared by solvent blending. Improved dispersion of graphene in PE/OPE blends substantially decreases percolation from both rheological (0.3 vol%) and electrical (0.13 vol%) measurements compared to neat PE nanocomposites (1 and 0.29 vol%), respectively. A universal Brownian dispersion of graphene in polymers was concluded similar to that of nanotubes, following the Doi-Edwards theory. Micromechanical models, such as Mori-Tanaka and Halpin-Tsai models, modeled the mechanical properties of the nanocomposites. The nanocomposites microstructure, studied by small angle x-ray scattering, confirmed better dispersion of graphene at lower loadings and the formation of surface fractals in the blend/graphene nanocomposites; whereas only mass fractals were observed in neat PE/graphene nanocomposites.

  18. Atomic structure of solid and liquid polyethylene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, J.A.; Saboungi, M.; Price, D.L.; Ansell, S. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Russell, T.P. [Polymer Science and Engineering Department, University of Massachusetts, Amherst, Massachusetts 01003 (United States); Halley, J.W.; Nielsen, B. [Department of Physics, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    1998-10-01

    The structure of polyethylene oxide (PEO) was investigated by neutron scattering in both semicrystalline and liquid states. Deuterated samples were studied in addition to the protonated ones in order to avoid the large incoherent scattering of hydrogen and identify features in the pair correlation functions attributable to C{endash}H pairs. Analysis of the deuterated sample gave additional information on the C{endash}O and C{endash}C pairs. The results are compared with molecular-dynamics simulations of liquid PEO. {copyright} {ital 1998 American Institute of Physics.}

  19. Lithium ion transport in a model of amorphous polyethylene oxide.

    Energy Technology Data Exchange (ETDEWEB)

    Boinske, P. T.; Curtiss, L.; Halley, J. W.; Lin, B.; Sutjianto, A.; Chemical Engineering; Univ. of Minnesota

    1996-01-01

    We have made a molecular dynamics study of transport of a single lithium ion in a previously reported model of amorphous polyethylene oxide. New ab initio calculations of the interaction of the lithium ion with 1,2-dimethoxyethane and with dimethyl ether are reported which are used to determine force fields for the simulation. We report preliminary calculations of solvation energies and hopping barriers and a calculation of the ionic conductivity which is independent of any assumptions about the mechanism of ion transport. We also report some details of a study of transport of the trapped lithium ion on intermediate time and length scales.

  20. Syntheses of Poly(ethylene oxide) Macromonomers Carrying Tertiary Amine and Quaternary Ammonium End Groups

    National Research Council Canada - National Science Library

    Senyo, Takamichi; Atago, Yuji; Liang, Huanan; Shen, Renhua; Ito, Koichi

    2003-01-01

    p-Vinylbenzyl alcohol, partially alkoxidated with potassium naphthalene, was used successfully to initiate living polymerization of ethylene oxide to afford α-p-vinylbenzyl-ω-hydroxy poly(ethylene oxide) (PEO) macromonomers. The ω...

  1. Neutral polyethylene oxide with a cofactor recommended for particle flocculation

    Directory of Open Access Journals (Sweden)

    M. R Abdallah/Qasaimeh

    2011-09-01

    Full Text Available Conventional and neutral high molecular weight polyethylene oxide (PEO adsorbs on some colloids and fines, flocculating them into flocs. Addition of a cofactor (CF makes PEO adsorb on all types of colloids and fines, flocculating them into larger flocs. Homoflocculation of fines with PEO alone and with CF added prior to PEO were investigated in this work at low and high effective shear rates. CF role was investigated: it enhanced flocculation amplitude and rate by several magnitudes relative to PEO used alone, and was ascribed to the CF action to stiffen and extend PEO coils. Considering CF-PEO abilities in homoflocculation and in heteroflocculation as recorded in the literature, combination of homo - and heteroflocculation can now be applied to processes. Formed flocs and individual particles will simultaneously deposit onto fibers and, when filtered, particles will be retained in the fiber cake. This technique can be applied in industry processes and water treatment.

  2. Synthesis and characterization of polyethylene oxide based nano composite electrolyte

    Indian Academy of Sciences (India)

    M Malathi; K Tamilarasan

    2014-08-01

    Polyethylene oxide (PEO) – montmorillonite (MMT) composite electrolytes were synthesised by solution casting technique. The salt used for the study is Lithium perchlorate (LiClO4). The morphology and percentage of crystallinity data were obtained through X-ray Diffraction and Differential Scanning Caloriemetry. The ionic conductivity of the polymer electrolytes was studied by impedance spectroscopy. The addition of MMT resulted in an increase in conductivity over the temperature range of 25–60°C. The ionic conductivity of a composite polymer electrolyte containing 1.2 wt% MMT was 1 × 10-5 S cm−1 at 25°C, which is at least one order of magnitude higher than that of the polymer electrolyte (4 × 10-7S cm−1). The increase in ionic conductivity is explained on the basis of crystallinity of the polymer electrolyte.

  3. Diffusivities and Viscosities of Poly(ethylene oxide) Oligomers †

    KAUST Repository

    Hong, Bingbing

    2010-10-14

    Diffusivities and viscosities of poly(ethylene oxide) (PEO) oligomer melts with 1 to 12 repeat units have been obtained from equilibrium molecular dynamics simulations using the TraPPE-UA force field. The simulations generated diffusion coefficients with high accuracy for all of the molar masses studied, but the statistical uncertainties in the viscosity calculations were significantly larger for longer chains. There is good agreement of the calculated viscosities and densities with available experimental data, and thus, the simulations can be used to bridge gaps in the data and for extrapolations with respect to chain length, temperature, and pressure. We explored the convergence characteristics of the Green-Kubo formulas for different chain lengths and propose minimal production times required for convergence of the transport properties. The chain-length dependence of the transport properties suggests that neither Rouse nor reptation models are applicable in the short-chain regime investigated. © 2010 American Chemical Society.

  4. PREPARATION OF ZINC OXIDE AND POLY-ETHYLENE OXIDE COMPOSITE MEMBRANES AND THEIR PHASE RELATIONSHIP

    OpenAIRE

    JESÚS FABIAN JURADO; CARLOS VARGAS HERNÁNDEZ; RUBÉN ANTONIO VARGAS

    2012-01-01

    Zinc oxide and organic polymer (poly-ethylene oxide) based nanocomposite membranes were prepared and their phase relationship investigated. The composites were characterized by XRD, Raman scattering, DSC, and impedance spectroscopy analysis. It was found that embedding inorganic nanoparticles of ZnO into the polymer matrix of PEO allowed for some crystallinity formation, and cross-linking of the polymer composites during annealing or synthesis. The XRD and Raman scattering results show more d...

  5. Oxidation of polyethylene implanted with low energy magnesium ions

    Energy Technology Data Exchange (ETDEWEB)

    Deslandes, Alec, E-mail: acd@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Sydney (Australia); Ionescu, Mihail, E-mail: mio@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Sydney (Australia); Karatchevtseva, Inna, E-mail: ikm@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Sydney (Australia); Siegele, Rainer, E-mail: rns@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Sydney (Australia); Cohen, David D., E-mail: dcz@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Sydney (Australia)

    2013-07-15

    The oxidation of polyethylene implanted with low energy, i.e. 25–50 keV, Mg ions to fluences from 5 × 10{sup 12}–5 × 10{sup 16} ions/cm{sup 2} was studied. Rutherford back-scattering spectroscopy showed all implanted samples gained oxygen but the distribution did not match that of the implanted Mg. An increase in carbon content was also observed for the near-surface region. Depth profiles of hydrogen were obtained via elastic recoil detection analysis, showing that hydrogen was lost throughout and beyond the range of the Mg ions, producing unsaturated and chemically active sites available for oxidation. Fourier-transform infrared spectroscopy revealed the formation of carbon–oxygen bonding such as carbonyl groups, but showed no evidence of oxidised magnesium. Raman spectroscopy showed disordered and graphitic carbon bonding configurations were created by the irradiation, but no evidence of oxidised magnesium. The implantation of films to high fluence produced a carbonized surface-layer that made the irradiated polymer more resistant to oxidation.

  6. Facile synthesis of dendrimer-like star-branched poly(isopropylacrylamide) via combination of click chemistry and atom transfer radical polymerization

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    We report a facile synthesis method of dendrimer-like star-branched poly(N-isopropylacrylamide) (PNIPAM) via the combination of click chemistry and atom transfer radical polymerization (ATRP) by employing the arm-first approach.First,the α-azido-ω-chloro-heterodifunctionalized building block,N3-PNIPAM-Cl (G0-Cl),was synthesized via ATRP by 3-azidopropyl 2-chloropropionate as the initiator.Taking advantage of click chemistry,the first generation (G1) of dendrimer-like star-branched PNIPAM,G1-(Cl)3,was facilely prepared via the click coupling reaction between G0-Cl and tripropargylamine.For the construction of second generation (G2) dendrimer-like star-branched PNIPAM,G2-(Cl)6,terminal chloride moieties of G1-(Cl)3 were first converted to azide,and then reacted with excess tripropargylamine to give G1-(alkynyl)6 ;G2-(Cl)6 was subsequently prepared via click reaction between G1-(alkynyl) 6 and G0-Cl.Gel permeation chromatography (GPC) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry were employed to confirm the successful construction of dendrimer-like star-branched polymers.The unique thermal phase transition behavior of this dendrimer-like star-branched polymer in aqueous solutions was further investigated by turbidimetry and micro-differential scanning calorimetry (Micro-DSC).

  7. Platelet deposition studies on copolyether urethanes modified with poly(ethylene oxide)

    NARCIS (Netherlands)

    Brinkman, E.; Foot, A.; van der Does, L.; Bantjes, A.

    1990-01-01

    Pellethane ® 2363 80A films and tubings were chemically modified and the effect of these modifications on platelet deposition was studied. Grafting of high molecular weight poly(ethylene oxide) and graft polymerization of methoxy poly(ethylene glycol) 400 methacrylate resulted in surfaces with a

  8. Stability of β-carotene in polyethylene oxide electrospun nanofibers

    Science.gov (United States)

    Peinado, I.; Mason, M.; Romano, A.; Biasioli, F.; Scampicchio, M.

    2016-05-01

    β-carotene (βc) was successfully incorporated into electrospun nanofibers of poly-(ethylene oxide) (PEO) with the aim of prolonging its shelf life and thermal stability. The physical and thermal properties of the βc-PEO-nanofibers were determined by scanning electron microscopy (SEM), color analysis, and differential scanning calorimetry (DSC). The nanofibers of PEO and βc-PEO exhibited average fiber diameters of 320 ± 46 and 230 ± 21 nm, with colorimetric coordinates L* = 95.7 ± 2.4 and 89.4 ± 4.6 and b* = -0.5 ± 0.1 and 6.2 ± 3.0 respectively. Thermogravimetric analysis coupled with Proton Transfer-Mass Spectroscopy (TGA/PTR-ms) demonstrated that coated βc inside PEO nanofibers increased thermal stability when compared to standard βc in powder form. In addition, β-carotene in the membranes showed higher stability during storage when compared with β-carotene in solution with a decrease in concentration of 57 ± 4% and 70 ± 2% respectively, thus should extend the shelf life of this compound. Also, TGA coupled with PTR-MS resulted in a promising technique to online-monitoring thermal degradation.

  9. Mechanisms of lithium transport in amorphous polyethylene oxide

    Science.gov (United States)

    Duan, Yuhua; Halley, J. W.; Curtiss, Larry; Redfern, Paul

    2005-02-01

    We report calculations using a previously reported model of lithium perchlorate in polyethylene oxide in order to understand the mechanism of lithium transport in these systems. Using an algorithm suggested by Voter, we find results for the diffusion rate which are quite close to experimental values. By analysis of the individual events in which large lithium motions occur during short times, we find that no single type of rearrangement of the lithium environment characterizes these events. We estimate the free energies of the lithium ion as a function of position during these events by calculation of potentials of mean force and thus derive an approximate map of the free energy as a function of lithium position during these events. The results are consistent with a Marcus-like picture in which the system slowly climbs a free energy barrier dominated by rearrangement of the polymer around the lithium ions, after which the lithium moves very quickly to a new position. Reducing the torsion forces in the model causes the diffusion rates to increase.

  10. Conductivity and Dielectric Studies of Lithium Trifluoromethanesulfonate Doped Polyethylene Oxide-Graphene Oxide Blend Based Electrolytes

    OpenAIRE

    Azli, A. A.; N. S. A. Manan; M. F. Z. Kadir

    2015-01-01

    Series of polymer blend consisting of polyethylene oxide (PEO) and graphene oxide (GO) as co-host polymer were prepared using solution cast method. The most amorphous PEO-GO blend was obtained using 90 wt.% of PEO and 10 wt.% of GO as recorded by X-ray diffraction (XRD). Fourier transform infrared spectroscopy (FTIR) analysis proved the interaction between PEO, GO, lithium trifluoromethanesulfonate (LiCF3SO3), and ethylene sulfite (ES). Incorporation of 25 wt.% LiCF3SO3 into the PEO-GO blend ...

  11. Various-sourced pectin and polyethylene oxide electrospun fibers.

    Science.gov (United States)

    Rockwell, Pamela L; Kiechel, Marjorie A; Atchison, Jennifer S; Toth, Laura J; Schauer, Caroline L

    2014-07-17

    Pectin, a naturally occurring and biorenewable polysaccharide, is derived from plant cell wall tissue and used in applications ranging from food processing to biomedical engineering. Due to extraction methods and source variation, there is currently no consensus in literature as to the exact structure of pectin. Here, we have studied key material properties of electrospun pectin blends with polyethylene oxide (PEO) (1:1, v/v) in order to demonstrate the fabrication of a fibrous and less toxic material system, as well as to understand the effects of source variability on the resulting fibrous mats. The bulk pectin degree of esterification (DE) estimated using FTIR (bulk apple pomace (AP)=28%, bulk citrus peel (CP)=86% and bulk sugar beet pulp (SBP)=91%) was shown to inversely correlate with electrospun fiber crystallinity determined using XRD (PEO-AP=37%, PEO-CP=28% and PEO-SBP=23%). This in turn affected the trend observed for the mean fiber diameter (n=50) (PEO-AP=124 ± 26 nm, PEO-CP=493 ± 254 nm and PEO-SBP=581 ± 178 nm) and elastic tensile moduli (1.6 ± 0.2 MPa, 4.37 ± 0.64 MPa and 2.49 ± 1.46 MPa, respectively) of the fibrous mats. Electrospun fibers containing bulk AP had the lowest DE, highest crystallinity, smallest mean fiber diameter, and lowest tensile modulus compared to either the bulk CP or bulk SBP. Bound water in PEO-CP fiber and bulk pectin impurities in PEO-SPB were observed to influence fiber branching and mean diameter distributions, which in turn influenced the fiber tensile properties. These results indicate that pectin, when blended with PEO in water, produces submicron fibrous mats with pectin influencing the blend fiber properties. Moreover, the source of pectin is an important variable in creating electrospun blend fibrous mats with desired material properties.

  12. Stability of β-carotene in polyethylene oxide electrospun nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Peinado, I., E-mail: irpeipar@upvnet.upv.es [Free University of Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Mason, M.; Romano, A. [Free University of Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Biasioli, F. [Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach (FEM), via E. Mach 1, 38010 San Michele all ‘Adige, TN (Italy); Scampicchio, M., E-mail: matteo.scampicchio@unibz.it [Free University of Bolzano, Piazza Università 5, 39100 Bolzano (Italy)

    2016-05-01

    Highlights: • β-carotene was incorporated into PEO-nanofibers by electrospinning. • Properties of the fibers were analyzed by SEM, color analysis, and DSC. • TGA coupled to PTR–ms resulted promising to online-monitoring thermal degradation. • Thermal stability of βc increased after encapsulation into the PEO-nanofibers. - Abstract: β-carotene (βc) was successfully incorporated into electrospun nanofibers of poly-(ethylene oxide) (PEO) with the aim of prolonging its shelf life and thermal stability. The physical and thermal properties of the βc-PEO-nanofibers were determined by scanning electron microscopy (SEM), color analysis, and differential scanning calorimetry (DSC). The nanofibers of PEO and βc-PEO exhibited average fiber diameters of 320 ± 46 and 230 ± 21 nm, with colorimetric coordinates L* = 95.7 ± 2.4 and 89.4 ± 4.6 and b* = −0.5 ± 0.1 and 6.2 ± 3.0 respectively. Thermogravimetric analysis coupled with Proton Transfer–Mass Spectroscopy (TGA/PTR–ms) demonstrated that coated βc inside PEO nanofibers increased thermal stability when compared to standard βc in powder form. In addition, β-carotene in the membranes showed higher stability during storage when compared with β-carotene in solution with a decrease in concentration of 57 ± 4% and 70 ± 2% respectively, thus should extend the shelf life of this compound. Also, TGA coupled with PTR–MS resulted in a promising technique to online-monitoring thermal degradation.

  13. Influence of Polyethylene and Oxidized Polyethylene Wax Emulsions on Leaching Dynamics of Boric Acid from Impregnated Spruce Wood

    Directory of Open Access Journals (Sweden)

    Boštjan Lesar

    2010-12-01

    Full Text Available Boron biocides belong to the most frequently used ingredients of commercial wood preservatives. They are very effective fungicides and insecticides, but they do not react with wood and thus leach from it in wet applications. This fact signifi cantly limits use of boron compounds in the field of wood preservation. In order to reduce leaching of boric acid, the emulsion of polyethylene (WE1 and an emulsion of oxidized polyethylene (WE6 wax were combined with boric acid (cB = 0.1 % or 0.5 % of boron. Spruce wood specimens were vacuum impregnated and afterwards leached according to the prCEN/TS 15119-1, EN 1250-2 and EN 84 procedures. The results showed that the boron leaching is predominantly infl uenced by moisture content of wood during leaching, and furthermore by the concentration gradient (frequency of water replacement. The fact that the prCEN/TS 15119-1 leaching procedure is less severe than other two methods is also refl ected in the results. The results of the EN 84 and ENV 1250 test are comparable, while the results of the prCEN/TS 15119-1 testing are not in line with the other two methods. Considerable portions of boron are leached from wood in the first leaching cycles, already. WE6 wax emulsion (oxidized polyethylene wax emulsion in combination with heat treatment reduces boron leaching to a certain extent. On the other hand, impregnation of wood with WE1 (polyethylene wax emulsion does not reduce it and it even enhances it.

  14. Multimeric, Multifunctional Derivatives of Poly(ethylene glycol

    Directory of Open Access Journals (Sweden)

    Gian Maria Bonora

    2011-07-01

    Full Text Available This article reviews the use of multifunctional polymers founded on high-molecular weight poly(ethylene glycol (PEG. The design of new PEG derivatives assembled in a dendrimer-like multimeric fashion or bearing different functionalities on the same molecule is described. Their use as new drug delivery systems based on the conjugation of multiple copies or diversely active drugs on the same biocompatible support is illustrated.

  15. FORMATION OF MOLYBDENUM OXIDE NANOSTRUCTURES CONTROLLED BY POLY(ETHYLENE OXIDE)

    Institute of Scientific and Technical Information of China (English)

    Chirakkal V. Krishnan; Rafael Munoz-Espi; Qi Li; Christian Burger; Benjamin Chu

    2009-01-01

    Polymeric systems have played an important role as structure-directing agents and in the control of nucleation and growth of crystals.This article reviews the work of our research group in the field of the polymer-assisted crystallization of inorganic materials,mainly focused on the formation of highly ordered,porous molybdenum oxide nanostructures.Different experimental parameters including the influence of poly(ethylene oxide)-containing polymers on the morphology and structure of the products obtained from peroxomolybdate solutions are examined.Our electrochemical investigations on molybdate species are also briefly described.Finally,the importance of the precursor species in the formation of the final product is discussed.

  16. Effect of ultraviolet radiation in the photo-oxidation of High Density Polyethylene and Biodegradable Polyethylene films

    Science.gov (United States)

    Martínez-Romo, A.; González Mota, R.; Bernal, J. J. Soto; Frausto Reyes, C.; Rosales Candelas, I.

    2015-01-01

    One of the most widely used plastics in the world is the High density polyethylene (HDPE), it is a stable material due to its carbon-carbon bonds, causing their slow degradation; which is why we are looking for alternative ways to accelerate the degradation process of this polymer. An alternative is the addition of oxidized groups in its molecular structure, which results in the development of polymers susceptible to biodegradation (PE-BIO). In this paper, HDPE and PE-BIO films were exposed to UV-B radiation (320-280 nm) at different exposure times, 0-60 days. The effects of UV radiation in samples of HDPE and PE-BIO were characterized using infrared spectroscopy with attenuated total reflectance (ATR). The results show that the exposed materials undergo changes in their molecular structure, due to the infrared bands formed which corresponds to the photo-oxidation of HDPE and PE films when submitted to UV-B radiation.

  17. Temperature-Dependent Deicing Properties of Electrostatically Anchored Branched Brush Layers of Poly(ethylene oxide).

    Science.gov (United States)

    Heydari, Golrokh; Tyrode, Eric; Visnevskij, Ceslav; Makuska, Ricardas; Claesson, Per M

    2016-05-03

    The hydration water of hydrophilic polymers freezes at subzero temperatures. The adsorption of such polymers will result in a hydrophilic surface layer that strongly binds water. Provided this interfacial hydration water remains liquidlike at subzero temperatures, its presence could possibly reduce ice adhesion, in particular, if the liquidlike layer is thicker than or comparable to the surface roughness. To explore this idea, a diblock copolymer, having one branched bottle-brush block of poly(ethylene oxide) and one linear cationic block, was electrostatically anchored on flat silica surfaces. The shear ice adhesion strength on such polymer-coated surfaces was investigated down to -25 °C using a homebuilt device. In addition, the temperature dependence of the ice adhesion on surfaces coated with only the cationic block, only the branched bottle-brush block, and with linear poly(ethylene oxide) was investigated. Significant ice adhesion reduction, in particular, at temperatures above -15 °C, was observed on silica surfaces coated with the electrostatically anchored diblock copolymer. Differential scanning calorimetry measurements on bulk polymer solutions demonstrate different thermal transitions of water interacting with branched and linear poly(ethylene oxide) (with hydration water melting points of about -18 and -10 °C, respectively). This difference is consistent with the low shear ice adhesion strength measured on surfaces carrying branched bottle-brush structured poly(ethylene oxide) at -10 °C, whereas no significant adhesion reduction was obtained with linear poly(ethylene oxide) at this temperature. We propose a lubrication effect of the hydration water bound to the branched bottle-brush structured poly(ethylene oxide), which, in the bulk, does not freeze until -18 °C.

  18. Polystyrene-b-polyethylene oxide block copolymer membranes, methods of making, and methods of use

    KAUST Repository

    Peinemann, Klaus-Viktor

    2015-04-16

    Embodiments of the present disclosure provide for polystyrene-b-polyethylene oxide (PS-b-PEO) block copolymer nanoporous membranes, methods of making a PS-b-PEO block copolymer nanoporous membrane, methods of using PS-b-PEO block copolymer nanoporous membranes, and the like.

  19. Unique Crystal Orientation of Poly(ethylene oxide) Thin Films by Crystallization Using a Thermal Gradient

    DEFF Research Database (Denmark)

    Gbabode, Gabin; Delvaux, Maxime; Schweicher, Guillaume

    2017-01-01

    Poly(ethylene oxide), (PEO), thin films of different thicknesses (220, 450, and 1500 nm) and molecular masses (4000, 8000, and 20000 g/mol) have been fabricated by spin-coating of methanol solutions onto glass substrates. All these samples have been recrystallized from the melt using a directional...

  20. Iridescent cellulose nanocrystal/polyethylene oxide composite films with low coefficient of thermal expansion

    Science.gov (United States)

    Jairo A. Diaz; Julia L. Braun; Robert J. Moon; Jeffrey P. Youngblood

    2015-01-01

    Simultaneous control over optical and thermal properties is particularly challenging and highly desired in fields like organic electronics. Here we incorporated cellulose nanocrystals (CNCs) into polyethylene oxide (PEO) in an attempt to preserve the iridescent CNC optical reflection given by their chiral nematic organisation, while reducing the composite thermal...

  1. Gas-permeation properties of poly(ethylene oxide) poly(butylene terephthalate block copolymers

    NARCIS (Netherlands)

    Metz, S.J.; Mulder, M.H.V.; Wessling, M.

    2004-01-01

    This paper reports the gas-permeation properties of poly(ethylene oxide) (PEO) poly(butylene terephthalate) (PBT) segmented multiblock copolymers. These block copolymers allow a precise structural modification by the amount of PBT and the PEO segment length, enabling a systematic study of the relati

  2. Phase separation of aqueous mixtures of poly(ethylene oxide) and dextran

    NARCIS (Netherlands)

    Edelman, M.W.; Linden, van der E.; Tromp, R.H.

    2003-01-01

    Abstract: The phase behavior of aqueous mixtures of poly(ethylene oxide) (PEO) and dextran is studied as a function of the polymer concentration, the PEO molar mass, and temperature. The molar mass distributions of the two polymers in the coexisting phases are measured. From the temperature dependen

  3. Microbial adhesion to poly(ethylene oxide) brushes: Influence of polymer chain length and temperature

    NARCIS (Netherlands)

    Roosjen, A.; Mei, van der H.C.; Busscher, H.J.; Norde, W.

    2004-01-01

    Glass surfaces were modified by end-grafting poly(ethylene oxide) (PEO) chains having molecular weights of 526, 2000, or 9800 Da. Characterization using water contact angles, ellipsometry, and X-ray photoelectron spectroscopy confirmed the presence of the PEO brushes on the surface with estimated le

  4. Microbial adhesion to poly(ethylene oxide) brushes : Influence of polymer chain length and temperature

    NARCIS (Netherlands)

    Roosjen, A; van der Mei, HC; Busscher, HJ; Norde, W

    2004-01-01

    Glass surfaces were modified by end-grafting poly(ethylene oxide) (PEO) chains having molecular weights of 526,2000, or 9800 Da. Characterization using water contact angles, ellipsometry, and X-ray photoelectron spectroscopy confirmed the presence of the PEO brushes on the surface with estimated len

  5. Surface properties of poly(ethylene oxide)-based segmented block copolymers with monodisperse hard segments

    NARCIS (Netherlands)

    Husken, D.; Feijen, Jan; Gaymans, R.J.

    2009-01-01

    The surface properties of segmented block copolymers based on poly(ethylene oxide) (PEO) segments and monodisperse crystallizable tetra-amide segments were studied. The monodisperse crystallizable segments (T6T6T) were based on terephthalate (T) and hexamethylenediamine (6). Due to the crystallinity

  6. Ultra High Molecular Weight Polyethylene/Graphene Oxide Nanocomposites: Thermal, Mechanical and Wettability Characterisation

    OpenAIRE

    2015-01-01

    Ultra high molecular weight polyethylene (UHMWPE) is the material most commonly used among hard-on-soft bearings in artificial joints. However, the eventual failure of joint implants has been directly related to the wear and oxidation resistance of UHMWPE. The development of novel materials with improved wear and oxidative characteristics has generated great interest in the orthopaedic community and numerous carbon nanostructures have been investigated in the last years due to their excellent...

  7. IONIC CONDUCTIVITY OF METHYLSILOXANE TERMINATED POLYETHYLENE OXIDE WITH LITHIUM PERCHLORATE NETWORK FILMS

    Institute of Scientific and Technical Information of China (English)

    LI Yongjun; FU Yingwen; FANG Shibi; JIANG Yingyan

    1988-01-01

    Complex films of crosslinked poly(methylsiloxane-co-ethylene oxide) and lithium perchlorate were prepared. These solid state polymeric electrolytes show a markedly higher ionic conductivity, and excellent flexibility. The ionic conductivity of the network films closed to 10-5 Scm-1 at room temperature. The effects of Li + content, species and contents of crosslinking agents, molecular weight of poly(ethylene oxide)and temperature on the ionic conductivity of the network films were also investigated.

  8. Self-consistent-field analysis of the micellization of carboxy-modified poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers

    NARCIS (Netherlands)

    Lauw, Y.; Leermakers, F.A.M.; Cohen Stuart, M.A.

    2006-01-01

    The micellization properties of carboxy-modified Pluronics P85 (poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers) are investigated by means of a molecularly realistic self-consistent-field theory. We consider the, so-called, carboxylic acid

  9. Self-consistent-field analysis of the micellization of carboxy-modified poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers

    NARCIS (Netherlands)

    Lauw, Y.; Leermakers, F.A.M.; Cohen Stuart, M.A.

    2006-01-01

    The micellization properties of carboxy-modified Pluronics P85 (poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers) are investigated by means of a molecularly realistic self-consistent-field theory. We consider the, so-called, carboxylic acid end-standi

  10. Extrusion of polysaccharide nanocrystal reinforced polymer nanocomposites through compatibilization with poly(ethylene oxide).

    Science.gov (United States)

    Pereda, Mariana; El Kissi, Nadia; Dufresne, Alain

    2014-06-25

    Polysaccharide nanocrystals with a rodlike shape but with different dimensions and specific surface area were prepared from cotton and capim dourado cellulose, and with a plateletlike morphology from waxy maize starch granules. The rheological behavior of aqueous solutions of poly(ethylene oxide) (PEO) with different molecular weights when adding these nanoparticles was investigated evidencing specific interactions between PEO chains and nanocrystals. Because PEO also bears hydrophobic moieties, it was employed as a compatibilizing agent for the melt processing of polymer nanocomposites. The freeze-dried mixtures were used to prepare nanocomposite materials with a low density polyethylene matrix by extrusion. The thermal and mechanical behavior of ensuing nanocomposites was studied.

  11. Conductivity and Dielectric Studies of Lithium Trifluoromethanesulfonate Doped Polyethylene Oxide-Graphene Oxide Blend Based Electrolytes

    Directory of Open Access Journals (Sweden)

    A. A. Azli

    2015-01-01

    Full Text Available Series of polymer blend consisting of polyethylene oxide (PEO and graphene oxide (GO as co-host polymer were prepared using solution cast method. The most amorphous PEO-GO blend was obtained using 90 wt.% of PEO and 10 wt.% of GO as recorded by X-ray diffraction (XRD. Fourier transform infrared spectroscopy (FTIR analysis proved the interaction between PEO, GO, lithium trifluoromethanesulfonate (LiCF3SO3, and ethylene sulfite (ES. Incorporation of 25 wt.% LiCF3SO3 into the PEO-GO blend increases the conductivity to 3.84±0.83×10-6 S cm−1. The conductivity starts to decrease when more than 25 wt.% salt is doped into the polymer blend. The addition of 1 wt.% ES into the polymer electrolyte has increased the conductivity to 1.73±0.05×10-5 S cm−1. Dielectric studies show that all the electrolytes obey non-Debye behavior.

  12. Investigation of thermal oxidative break-down of polyethylene films modified with grafted polyacrylonitrile. [Gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Krul, L.P.; Gert, E.V. (Belorusskij Gosudarstvennyj Univ., Minsk)

    1981-11-01

    Thermal oxidative destruction of polyethylene (PE) films modified by radiation (..gamma..-radiation, dose rate is 0.56 Mrad/hr) liquid-phase graft polymerization of acrylonitrile (AN) has been studied. Comparative stability of grafted copolymers, homopolymers and mechanical mixtures of PE and PAN (polyacrylonitrile) to thermal oxidative destruction is studied using the derivatographic method. It is shown that graft of PAN considerably decelerates the development of oxidative and destructive processes in PE, at that, the efficiency of PE chain stabilization increases with the increase of grafted PAN amount. The sample with PAN content x=0.367 (in parts of the mass of grafted film) possesses the highest stability.

  13. STUDIES ON ULTRASONIC GRAFTING OF POLY(VINYL ACETATE) WITH POLY(ETHYLENE OXIDE)

    Institute of Scientific and Technical Information of China (English)

    LI Wenduan; XU Xi; Tu Hong; Tang Zuyao

    1983-01-01

    The ultrasonic degradation of poly(ethylene oxide) and poly(vinyl acetate) in benzene solution, and grafting reaction of poly(vinyl acetate) with poly(ethylene oxide) were studied. It is found that the chain-scission reactions follow the course suggested by D. W. Ovenall. The structure of the copolymer was identified by IR, NMR and DTA, showing that the copolymer prepared is a graft copolymer mainly. The copolymer formed by irradiating 1 % PEO/PVAc solution (PEO/PVAc:1/1 by weight) for a period of 10 min at 18.2 kHz with 2.0 A input current on reversed main circuit, amounts to 10.5%.

  14. Synthesis, Characterization and Thermal Properties of Poly(ethylene oxide), PEO, Polymacromonomers via Anionic and Ring Opening Metathesis Polymerization

    National Research Council Canada - National Science Library

    George V Theodosopoulos; Christos Zisis; Georgios Charalambidis; Vasilis Nikolaou; Athanassios G Coutsolelos; Marinos Pitsikalis

    2017-01-01

    Branched polymers are a valuable class of polymeric materials. In the present study, anionic polymerization techniques were employed for the synthesis of low molecular weight poly(ethylene oxide) (PEO...

  15. Surface induced disorder of nematic MBBA near silica with grafted poly(ethylene oxide)

    OpenAIRE

    H. BEN OUADA; Hommel, H.; Legrand, A.P.; Balard, H.; Papirer, E.

    1986-01-01

    The order of a nematic liquid crystal, MBBA, in contact with a solid silica surface covered with grafted polymers poly(ethylene oxide) 2000, has been investigated by the electron paramagnetic resonance, the nuclear magnetic resonance and the differential scanning calorimetry. The different spectra, the transitions temperatures and the degree of order of the molecules are given. The results are consistent with an overall picture of the interface consisting of an intermediate layer formed by po...

  16. Simulation of polyethylene oxide : improved structure using better models for hydrogen and flexible walls.

    Energy Technology Data Exchange (ETDEWEB)

    Halley, J. W.; Duan, Y.; Nielsen, B.; Redfern, P. C.; Curtiss, L. A.; Univ. of Minnesota

    2001-08-22

    We describe calculations of the structure of amorphous polyethylene oxide using a previously reported model, but with better treatment of hydrogen positions and in a code which allows relaxation of stresses in the polymerized sample by Rahman-Parrinello techniques. We also report the effects of two different intermolecular force field potentials and find that our earlier, empirical force field produces better agreement with experimental neutron scattering results than a force field derived from ab initio electronic structure calculations.

  17. OPTIMIZATION AND CHARACTERIZATION OF POLYSULFONE MEMBRANES MADE OF ZINC OXIDE, POLYETHYLENE GLYCOL AND EUGENOL AS ADDITIVES

    OpenAIRE

    2016-01-01

    The aim of this study to investigate the effect of zinc oxide, polyethylene glycol (PEG) and eugenol on the properties of membranes made of polysulfone (PSf). Polysulfone membranes were prepared via phase inversion method using Nmethyl-2-pyrolidone (NMP) as a solvent and water as non-solvent. The membranes were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), porosity, tensile strength, permeability, rejection and antibacterial te...

  18. Magnetorheological behaviour and electrospinning of poly(ethylene oxide) suspensions with magnetic nanoparticles

    OpenAIRE

    2016-01-01

    The properties of poly(ethylene oxide) aqueous suspensions with magnetic nanoparticles synthesized under microwave-assisted radiation are studied. The magnetic nanoparticles are formed by iron (III) chloride hexahydrate (FeCl3·6H2O) dissolved in ethylene glycol (C2H4(OH)2) and subsequently in aqueous ammonia solution (approx. 25 wt% aq.). The polymer suspension exhibits substantial advantages over a suspension when 'classical' carrier fluids (water and silicone oil) are used. First, the prese...

  19. Phase behavior of mixtures of rods (tobacco mosaic virus) and spheres (polyethylene oxide, bovine serum albumin).

    OpenAIRE

    1998-01-01

    Aqueous suspensions of mixtures of the rodlike virus tobacco mosaic virus (TMV) with globular macromolecules such as polyethylene oxide (PEO) or bovine serum albumin (BSA) phase separate and exhibit rich and strikingly similar phase behavior. Isotropic, nematic, lamellar, and crystalline phases are observed as a function of the concentration of the constituents and ionic strength. The observed phase behavior is considered to arise from attractions between the two particles induced by the pres...

  20. Acrylic acid polymerization and its graft copolymerization to poly(ethylene oxide) by gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Hochberg, A.

    1984-01-01

    Free radical initiated polymerization of acrylic acid was investigated in methanol-water solutions with and without poly(ethylene oxide) (PEO). The formation of poly(acrylic acid) (PAA) initiated both by gamma irradiation and water soluble azo initiators was found to follow classical free radical kinetics. A significant increase in the rate of the propagation step (together with the degree of polymerization) was observed as the water fraction of the medium increased. During homogeneous polymerization of acrylic acid in methanol-water solutions containing poly(ethylene oxide), PAA grafting efficiency was found to be 67% and independent of initiation rate and yield. A mechanism of grafting to poly(ethylene oxide) was proposed. Chain transfer to PEO (K/sub tr/ = 6.5 x 10/sup -5/) was found to be the dominant mechanism for graft formation. Drag reduction characteristics of these PEO-PAA graft copolymers were measured in dilute aqueous solutions as a function of Reynolds number and solution pH. PEO graft copolymers containing 45% by mole PAA graft had, in neutral and basic solutions, drag reduction characteristics equivalent on a mass basis to the initial PEO. However at low pH, drag reduction characteristics disappeared as the PEO-PAA coacervate formed.

  1. Antibacterial wound dressing from chitosan/polyethylene oxide nanofibers mats embedded with silver nanoparticles.

    Science.gov (United States)

    Wang, Xiaoli; Cheng, Feng; Gao, Jing; Wang, Lu

    2015-03-01

    Novel antibacterial nanomaterials have been developed for biomedical applications. The present study involves the preparation and properties of antibacterial nanofibers from chitosan/polyethylene oxide electrospun nanofibers incorporated with silver nanoparticles. Silver nanoparticles were efficiently synthesized in situ after ultra violet (UV) with AgNO3 as precursor and chitosan/polyethylene oxide as reducing agent and protecting agent, respectively. Then the resultant solutions were electrospun into nanofibers. The formation of silver nanoparticles was confirmed with ultraviolet visible (UV-vis) and transmission electron microscopy (TEM), and the electrospun nanofibers were characterized by scanning electron microscopy and energy dispersive X-ray. The resultant fibers exhibited uniform morphology with silver nanoparticles distributed throughout the fiber. Also, the fibers showed certain tensile strength and excellent antibacterial activity against Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. Sustained release of silver nanoparticles from fibers could last for over 72 h. The silver-containing chitosan/polyethylene oxide nanofibers showed excellent cytocompatibility.

  2. Amphiphilic Polyphosphazene with Poly(ethylene oxide) Side Chains Prepared through the Decker-Forster Reaction

    Institute of Scientific and Technical Information of China (English)

    LIU Chengmei; HU Fuzhen; QIU Jinjun; LEI Guofu; BAO Rui

    2006-01-01

    Poly(4-methylphenoxyphosphazene)-graft-poly(ethylene oxide) (PPZ-g-PEO), a novel amphiphilic grafting polymer was prepared via the Decker-Forster reaction. It is found that the graft efficiency increased with extension of reaction time. Low molecular weight of poly(ethylene oxide) favored the grafting reaction. The grafted polymer has two different glass transition temperatures(Tg) with those of pure poly(4-methylphenoxy-phopsphazene) and PEO. The emulsifying ability of grafted polymer was studied with benzene-water mixture. The emulsifying volumes increased with the decreasing of PEO's molecular weight. The contact angle of film forming from grafted polymer decreased after introduction of PEO grafting chain.

  3. Oxidation in ultrahigh molecular weight polyethylene and cross-linked polyethylene acetabular cups tested against roughened femoral heads in a hip joint simulator.

    Science.gov (United States)

    Taddei, Paola; Affatato, Saverio; Fagnano, Concezio; Toni, Aldo

    2006-06-01

    This study was aimed at comparing the oxidative degradation of commercial acetabular cups made of cross-linked polyethylene (XLPE) and conventional ultrahigh molecular weight polyethylene (UHMWPE). After testing against deliberately scratched CoCrMo femoral heads in a hip joint simulator, the cups, microtomed parallel to the articulating surface, were analyzed by IR spectroscopy. Due to the potential for artifacts caused by absorbed contaminants, the IR spectra were compared only after hexane extraction; actually, XLPE was found to absorb more serum than UHMWPE. The two sets of unworn acetabular cups showed different oxidation patterns with consequently different distributions of carbonyl species; unworn XLPE was characterized by lower contents of carbonyl species and hydrogen-bonded alcohols and higher contents of trans-vinylene species than unworn UHMWPE. Upon simulator testing, UHMWPE showed more significant changes in oxidation indexes and distribution of carbonyl compounds than XLPE, confirming a better wear behavior for XLPE under the adopted testing conditions.

  4. Investigation of the interaction of copper(II) oxide and electron beam irradiation crosslinkable polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Bee, Soo-Tueen, E-mail: direct.beest@gmail.com [Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor (Malaysia); Sin, Lee Tin, E-mail: direct.tinsin@gmail.com [Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor (Malaysia); Ratnam, C.T. [Radiation Processing Technology Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Haraveen, K.J.S.; Tee, Tiam-Ting [Department of Chemical Engineering, Lee Kong Chian Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Sungai Long, Bandar Sungai Long, Cheras, 43000 Kajang, Selangor (Malaysia); Rahmat, A.R. [Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

    2015-10-01

    In this study, the effects of electron beam irradiation on the properties of copper(II) oxide when added to low-density polyethylene (LDPE) blends were investigated. It was found that the addition of low loading level of copper(II) oxide (⩽2 phr) to LDPE results in significantly poorer gel content and hot set results. However, the incorporation of higher loading level of copper(II) oxide (⩾3 phr) could slightly increase the degree of crosslinking in all irradiated LDPE composites. This is due to the fact that higher amounts of copper(II) oxide could slightly induce the formation of free radicals in LDPE matrix. Besides, increasing irradiation doses was also found to gradually increase the gel content of LDPE composites by generating higher amounts of free radicals. As a consequence, these higher amounts of free radicals released in the LDPE matrix could significantly increase the degree of crosslinking. The addition of copper(II) oxide could reduce the tensile strength and fracture strain (elongation at break) of LDPE composites because of poorer interfacial adhesion effect between copper(II) oxide particles and LDPE matrix. Meanwhile, increasing irradiation doses on all copper(II) oxide added LDPE composites could marginally increase the tensile strength. In addition, increasing irradiation dose could enhance the thermal stability of LDPE composites by increasing the decomposition temperature. The oxidation induction time (OIT) analysis showed that, because of the crosslinking network in the copper(II) oxide added LDPE composites, oxidation reaction is much delayed.

  5. Effect of oxidation on delamination of ultrahigh-molecular-weight polyethylene tibial components.

    Science.gov (United States)

    Bell, C J; Walker, P S; Abeysundera, M R; Simmons, J M; King, P M; Blunn, G W

    1998-04-01

    Whether oxidation of ultrahigh-molecular-weight polyethylene (UHMWPE) causes delamination of the plastic in total knee arthroplasties (TKAs) was investigated. Examination of retrieved TKAs has shown that oxidation of UHMWPE can be caused by postirradiation damage leading to a subsurface band or, to a lesser extent, by mechanical forces during use leading to surface oxidation. Delamination cracks propagated through the subsurface oxidized band. In wear tests, delamination occurred in artificially aged UHMWPE where only subsurface oxidized bands had formed. Increased surface wear predominated where oxidation was associated with the surface of the plastic. Similarly, in tensile and fatigue tests of oxidized UHMWPE, there was a significant reduction in the ultimate tensile strength and in the fatigue resistance of specimens that had developed a subsurface band. Oxidation increased fatigue crack growth rate. It was observed that UHMWPE from different manufacturers varied in its resistance to oxidation. This study demonstrates that the effect of oxidation, which results in the development of a subsurface white band, combined with high subsurface shear forces observed in TKAs, is to enhance delamination wear.

  6. Synthesis of cobalt stearate as oxidant additive for oxo-biodegradable polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Asriza, Ristika O.; Arcana, I Made, E-mail: arcana@chem.itb.ac.id [Division of Inorganic and Physical Chemistry, Institut Teknologi Bandung, Jl. Ganesha No. 10, Bandung, 40132 (Indonesia)

    2015-09-30

    Cobalt stearate is an oxidant additives that can initiate a process of degradation in high density polyethylene (HDPE). To determine the effect of cobalt stearate in HDPE, oxo-biodegradable polyethylene film was given an irradiation with UV light or heating at various temperature. After given a heating, the FTIR spectra showed a new absorption peak at wave number 1712 cm{sup −1} indicating the presence of carbonyl groups in polymers, whereas after irradiation with UV light is not visible the presence of this absorption peak. The increase concentration of cobalt stearate added in HDPE and the higher heating temperature, the intensity of the absorption peak of the carbonyl group increased. The increasing intensity of the carbonyl group absorption is caused the presence of damage in the film surface after heating, and this result is supported by analysis the surface properties of the film with using SEM. Biodegradation tests were performed on oxo-biodegradable polyethylene film which has been given heating or UV light with using activated sludge under optimal conditions the growth of microorganisms. After biodegradation, the maximum weight decreased by 23% in the oxo-biodegradable polyethylene film with a cobalt stearate concentration of 0.2% and after heating at a temperature of 75 °C for 10 days, and only 0.69% in the same film after irradiation UV light for 10 days. Based on the results above, cobalt stearate additive is more effective to initiate the oxidative degradation of HDPE when it is initiated by heating compared to irradiation with UV light.

  7. N-heterocyclic carbene-induced zwitterionic ring-opening polymerization of ethylene oxide and direct synthesis of alpha,omega-difunctionalized poly(ethylene oxide)s and poly(ethylene oxide)-b-poly(epsilon-caprolactone) block copolymers.

    Science.gov (United States)

    Raynaud, Jean; Absalon, Christelle; Gnanou, Yves; Taton, Daniel

    2009-03-11

    An N-heterocyclic carbene (NHC), namely, 1,3-bis-(diisopropyl)imidazol-2-ylidene (1), was demonstrated to bring about the metal-free ring-opening polymerization of ethylene oxide at 50 degrees C in dimethyl sulfoxide, in absence of any other reagents. Poly(ethylene oxide) (PEO) of polydispersities ethylene oxide to form a zwitterionic species, namely 1,3-bis-(diisopropyl)imidazol-2-ylidinium alkoxide, that further propagates by a zwitterionic ring-opening polymerization (ZROP) mechanism. Through an appropriate choice of terminating agent NuH or NuSiMe(3) at the completion of the polymerization, a variety of end-functionalized PEO chains could be generated. In particular, alpha,omega-bis(hydroxy)-telechelic PEO, alpha-benzyl,omega-hydroxy, and alpha-azido,omega-hydroxy-difunctionalized PEOs were synthesized by NHC (1)-initiated ZROP, using H(2)O, PhCH(2)OH, and N(3)SiMe(3) as terminating agent, respectively. Characterization of these alpha,omega-difunctionalized PEOs by techniques such as (1)H NMR spectroscopy, MALDI-TOF spectrometry, and size exclusion chromatography confirmed the quantitative introduction of functional groups at both alpha and omega positions of the PEO chains and the formation of very narrow molar mass polymers. Finally, the synthesis of a poly(ethylene oxide)-b-poly(epsilon-caprolactone) diblock copolymer by sequential ZROP of the corresponding monomers was successfully achieved using (1) as organic initiator without isolation of the PEO block intermediate.

  8. Revealing the Cytotoxicity of Residues of Phosphazene Catalysts Used for Synthesis of Poly(ethylene oxide)

    KAUST Repository

    Xia, Yening

    2017-08-24

    We herein report a case study on the toxicity of residual catalyst in metal-free polymer. Eight-arm star-like poly(ethylene oxide)s were successfully synthesized via phosphazene-catalyzed ring-opening polymerization of ethylene oxide using sucrose as an octahydroxy initiator. The products were subjected to MTT assay using human cancer cell lines (MDA-MB-231 and A2780). Comparison between the crude and purified products clearly revealed that the residual phosphazenium salts were considerably cytotoxic regardless of the anionic species, and that the cytotoxicity of more bulky t-BuP4 salt was higher than that of t-BuP2 salt. Such results have therefore put forward the necessity for removal of the catalyst residues from PEO-based polymers synthesized through phosphazene catalysis for bio-related applications, and for the development of less or non-toxic organocatalysts for such polymers.

  9. Electrospinning and Porosity Measurements of Nylon-6/Poly(ethylene oxide Blended Nonwovens

    Directory of Open Access Journals (Sweden)

    Margaret W. Frey, Ph.D.

    2007-04-01

    Full Text Available A simple method was used to prepare a nonwoven fabric of intimately co-mingled Nylon-6 and Polyethylene oxide (PEO electrospun fibers by spinning fibers onto a rotating collector. Electrospinning parameters for each polymer were independent. Fiber mixture and distribution was uniform throughout the depth of the fabric. Porosity and pore size distribution of the materials were measured before and after a washing treatment. The PEO component was removed during the washing step to create increased pore size in the remaining fabric. This study indicates a simple method to create nanofiber nonwovens of multiple dissimilar polymers and provides a strategy for controlling pore size distribution independently from fiber formation.

  10. Adhesion mapping of chemically modified and poly(ethylene oxide)-grafted glass surfaces

    OpenAIRE

    Jogikalmath, G.; Stuart, J.K.; Pungor, A.; Hlady, V.

    1999-01-01

    Two-dimensional mapping of the adhesion pull-off forces was used to study the origin of surface heterogeneity in the grafted poly(ethylene oxide) (PEO) layer. The variance of the pull-off forces measured over the μm-sized regions after each chemical step of modifying glass surfaces was taken to be a measure of the surface chemical heterogeneity. The attachment of γ-glycidoxypropyltrimethoxy silane (GPS) to glass decreased the pull-off forces relative to the clean glass and made the surface mo...

  11. Nanostructured carbon-crystalline titania composites from microphase separation of poly(ethylene oxide-b-acrylonitrile) and titania sols.

    Science.gov (United States)

    Stefik, Morgan; Lee, Jinwoo; Wiesner, Ulrich

    2009-05-14

    A simple "one-pot" method utilizing a graphitic carbon source containing poly(ethylene oxide-b-acrylonitrile) diblock copolymer as a structure directing agent was used to synthesize carbon-crystalline titania composites as well as crystalline mesoporous titania materials after oxidative carbon removal.

  12. Atomistic simulation of CO 2 solubility in poly(ethylene oxide) oligomers

    KAUST Repository

    Hong, Bingbing

    2013-10-02

    We have performed atomistic molecular dynamics simulations coupled with thermodynamic integration to obtain the excess chemical potential and pressure-composition phase diagrams for CO2 in poly(ethylene oxide) oligomers. Poly(ethylene oxide) dimethyl ether, CH3O(CH 2CH2O)nCH3 (PEO for short) is a widely applied physical solvent that forms the major organic constituent of a class of novel nanoparticle-based absorbents. Good predictions were obtained for pressure-composition-density relations for CO2 + PEO oligomers (2 ≤ n ≤ 12), using the Potoff force field for PEO [J. Chem. Phys. 136, 044514 (2012)] together with the TraPPE model for CO2 [AIChE J. 47, 1676 (2001)]. Water effects on Henrys constant of CO2 in PEO have also been investigated. Addition of modest amounts of water in PEO produces a relatively small increase in Henrys constant. Dependence of the calculated Henrys constant on the weight percentage of water falls on a temperature-dependent master curve, irrespective of PEO chain length. © 2013 Taylor & Francis.

  13. Molecular dynamics simulations of silica nanoparticles grafted with poly(ethylene oxide) oligomer chains.

    Science.gov (United States)

    Hong, Bingbing; Panagiotopoulos, Athanassios Z

    2012-03-01

    A molecular model of silica nanoparticles grafted with poly(ethylene oxide) oligomers has been developed for predicting the transport properties of nanoparticle organic-hybrid materials (NOHMs). Ungrafted silica nanoparticles in a medium of poly(ethylene oxide) oligomers were also simulated to clarify the effect of grafting on the dynamics of nanoparticles and chains. The model approximates nanoparticles as solid spheres and uses a united-atom representation for chains, including torsional and bond-bending interactions. The calculated viscosities from Green-Kubo relationships and temperature extrapolation are of the same order of magnitude as experimental data but show a smaller activation energy relative to real NOHMs systems. Grafted systems have higher viscosities, smaller diffusion coefficients, and slower chain dynamics than the ungrafted ones at high temperatures. At lower temperatures, grafted systems exhibit faster dynamics for both nanoparticles and chains relative to ungrafted systems, because of lower aggregation of particles and enhanced correlations between nanoparticles and chains. This agrees with the experimental observation that NOHMs have liquidlike behavior in the absence of a solvent. For both grafted and ungrafted systems at low temperatures, increasing chain length reduces the volume fraction of nanoparticles and accelerates the dynamics. However, at high temperatures, longer chains slow down nanoparticle diffusion. From the Stokes-Einstein relationship, it was determined that the coarse-grained treatment of nanoparticles leads to slip on the nanoparticle surfaces. Grafted systems obey the Stokes-Einstein relationship over the temperature range simulated, but ungrafted systems display deviations from it.

  14. Evaluation of doped polyethylene oxide as solid electrolyte for polymer batteries

    Science.gov (United States)

    Sircar, A. K.; Weissman, P. T.; Kumar, B.

    1992-02-01

    This report presents results of an investigation on the preparation and characterization of polyethylene oxide (PEO) and lithium tetrafluoroborate (LiBF4) complexes for application as solid electrolytes in polymer batteries. AC conductivity and permittivity (dielectric constant) were measured as functions of frequency, temperature, and concentration of lithium tetrafluoroborate (LiBF4) in polyethylene oxide (PEO) films. Differential Scanning Calorimetry (DSC) was used to trace changes of the morphology of the polymeric medium. Thermogravimetry (TG) and derivative thermogravimetry (DTG) were used to follow the decomposition of components and to define the maximum temperature limits for these measurements. Infrared Spectroscopy monitored structural evolution as the O:Li ratio in the polymer complex was varied. Thin films of a complex (O:Li = 8) were used to assemble Li/Polymer/Li Cell for electrochemical characterization. The study showed that the relationship of dopant concentration to electrical properties is rather complex. Degree of ion-pairing, dissociation of ions on dilution, changes in the morphology of the polymeric medium, and variations in viscosity and its consequence on ion mobility were considered to explain the data. An optimum in room conductivity occurred in a complex with O:Li ratio of 8.

  15. Atomistic simulation of CO2 solubility in poly(ethylene oxide) oligomers

    Science.gov (United States)

    Hong, Bingbing; Panagiotopoulos, Athanassios Z.

    2014-06-01

    We have performed atomistic molecular dynamics simulations coupled with thermodynamic integration to obtain the excess chemical potential and pressure-composition phase diagrams for CO2 in poly(ethylene oxide) oligomers. Poly(ethylene oxide) dimethyl ether, CH3O(CH2CH2O)nCH3 (PEO for short) is a widely applied physical solvent that forms the major organic constituent of a class of novel nanoparticle-based absorbents. Good predictions were obtained for pressure-composition-density relations for CO2 + PEO oligomers (2 ≤ n ≤ 12), using the Potoff force field for PEO [J. Chem. Phys. 136, 044514 (2012)] together with the TraPPE model for CO2 [AIChE J. 47, 1676 (2001)]. Water effects on Henry's constant of CO2 in PEO have also been investigated. Addition of modest amounts of water in PEO produces a relatively small increase in Henry's constant. Dependence of the calculated Henry's constant on the weight percentage of water falls on a temperature-dependent master curve, irrespective of PEO chain length.

  16. The influence of oxidation on space charge formation in gamma-irradiated low-density polyethylene

    CERN Document Server

    Chen, G; Xie, H K; Banford, H M; Davies, A E

    2003-01-01

    The research presented in this paper investigates the role of oxidation in the formation of space charge in gamma-irradiated low-density polyethylene after being electrically stressed under dc voltage. Polyethylene plaques both with and without antioxidant were irradiated up to 500 kGy using a sup 6 sup 0 Co gamma source and space charge distributions were measured using the piezoelectric induced pressure wave propagation method. It has been found that a large amount of positive charge evolved adjacent to the cathode in the sample without antioxidant and was clearly associated with oxidation of the surface. The amount of charge formed for a given applied stress increased with the dose absorbed by the material. A model has been proposed to explain the formation of space charge and its profile. The charge decay after the removal of the external applied stress is dominated by a process being controlled by the cathode interfacial stress (charge injection) rather than a conventional RC circuit model. On the other ...

  17. Electrical Characterization of Polyaniline/polyethylene Oxide Nanofibers for Field Effect Transistors

    Science.gov (United States)

    Mueller, Carl H.; Theofylaktos, Noulie; Pinto, Nicholas J.; Robinson, Daryl C.; Miranda, Felix A.

    2002-01-01

    Nanofibers comprised of polyaniline/polyethylene oxide (PANI/PEO) are being developed for novel logic devices. We report the electrical conductivity of PANI/PEO nanofibers with diameters in the 100 to 200 nm range. We measured conductivity values of approx. 0.3 to 1.0 S/cm, which is higher than the values reported for thicker nanofibers, but less than the bulk value of PANI. The electrical measurements were performed by depositing the fibers on pre-electroded, oxidized silicon (Si) substrates. The excellent adherence of the nanofibers to the SiO2 as well as the gold (Au) electrodes may be useful in the design of future devices.

  18. Mixed Matrix PVDF Membranes With in Situ Synthesized PAMAM Dendrimer-Like Particles: A New Class of Sorbents for Cu(II) Recovery from Aqueous Solutions by Ultrafiltration.

    Science.gov (United States)

    Kotte, Madhusudhana Rao; Kuvarega, Alex T; Cho, Manki; Mamba, Bhekie B; Diallo, Mamadou S

    2015-08-18

    Advances in industrial ecology, desalination, and resource recovery have established that industrial wastewater, seawater, and brines are important and largely untapped sources of critical metals and elements. A Grand Challenge in metal recovery from industrial wastewater is to design and synthesize high capacity, recyclable and robust chelating ligands with tunable metal ion selectivity that can be efficiently processed into low-energy separation materials and modules. In our efforts to develop high capacity chelating membranes for metal recovery from impaired water, we report a one-pot method for the preparation of a new family of mixed matrix polyvinylidene fluoride (PVDF) membranes with in situ synthesized poly(amidoamine) [PAMAM] particles. The key feature of our new membrane preparation method is the in situ synthesis of PAMAM dendrimer-like particles in the dope solutions prior to membrane casting using low-generation dendrimers (G0 and G1-NH2) with terminal primary amine groups as precursors and epichlorohydrin (ECH) as cross-linker. By using a combined thermally induced phase separation (TIPS) and nonsolvent induced phase separation (NIPS) casting process, we successfully prepared a new family of asymmetric PVDF ultrafiltration membranes with (i) neutral and hydrophilic surface layers of average pore diameters of 22-45 nm, (ii) high loadings (∼48 wt %) of dendrimer-like PAMAM particles with average diameters of ∼1.3-2.4 μm, and (iii) matrices with sponge-like microstructures characteristics of membranes with strong mechanical integrity. Preliminary experiments show that these new mixed matrix PVDF membranes can serve as high capacity sorbents for Cu(II) recovery from aqueous solutions by ultrafiltration.

  19. New Aptes Cross-linked Polymers from Poly(ethylene oxide)s and Cyanuric Chloride for Lithium Batteries

    Science.gov (United States)

    Tigelaar, Dean M.; Meador, Mary Ann B.; Kinder, James D.; Bennett, William R.

    2005-01-01

    A new series of polymer electrolytes for use as membranes for lithium batteries are described. Electrolytes were made by polymerization between cyanuric chloride and diamino-terminated poly(ethylene oxide)s, followed by cross-linking via a sol-gel process. Thermal analysis and lithium conductivity of freestanding polymer films were studied. The effects of several variables on conductivity were investigated, such as length of backbone PEO chain, length of branching PEO chain, extent of branching, extent of cross-linking, salt content, and salt counterion. Polymer films with the highest percentage of PEO were found to be the most conductive, with a maximum lithium conductivity of 3.9 x 10(exp -5) S/cm at 25 C. Addition of plasticizer to the dry polymers increased conductivity by an order of magnitude.

  20. Sythesis and properties of segmented block copolymers based on mixtures of poly(ethylene oxide) and poly(tetramethylene oxide) segments

    NARCIS (Netherlands)

    Husken, D.; Feijen, Jan; Gaymans, R.J.

    2008-01-01

    The synthesis and characterisation of segmented block copolymers based on mixtures of hydrophilic poly(ethylene oxide) and hydrophobic poly(tetramethylene oxide) polyether segments and monodisperse crystallisable bisester tetra-amide segments are reported. The PEO length was varied from 600 to 8000

  1. Release of anti-restenosis drugs from poly(ethylene oxide)-poly (DL-lactic-co-glycolic acid) nanoparticles

    NARCIS (Netherlands)

    Zweers, Miechel L. T.; Engbers, Gerard H. M.; Grijpma, Dirk W.; Feijen, Jan

    2006-01-01

    Dexamethasone- or rapamycin-loaded nanoparticles based on poly(ethylene oxide) and poly(DL-lactic-co-glycolic acid) block copolymers (PEO-PLGA) were prepared without additional stabilizer using the salting-out method. A fast release of drug in PBS (PH 7.4) at 37 degrees C resulting in 100% release w

  2. Real-time imaging of melting and crystallization in poly(ethylene oxide) by atomic force microscopy

    NARCIS (Netherlands)

    Pearce, R.; Vancso, Gyula J.

    1998-01-01

    The processes of melting and crystallization of poly(ethylene oxide) are followed in real time at elevated temperature by atomic force microscopy using a simple hot stage apparatus. Hedritic development at a temperature of 57°C is monitored, including the process of lamellar splaying to yield a

  3. High molecular weight poly(L-lactide) and poly(ethylene oxide) blends : Thermal characterization and physical properties

    NARCIS (Netherlands)

    Nijenhuis, AJ; Colstee, E; Grijpma, DW; Pennings, AJ

    1996-01-01

    The miscibility of high molecular weight poly(L-lactide) (PLLA) with high molecular weight poly(ethylene oxide) (PEG) was studied by differential scanning calorimetry. Ail blends containing up to 50 weight% PEO showed single glass transition temperatures. The PLLA and PEO melting temperatures were f

  4. Mixed gas water vapor/N2 transport in poly(ethylene oxide) poly(butylene terephthalate) block copolymers

    NARCIS (Netherlands)

    Metz, S.J.; van de Ven, W.J.C.; Mulder, M.H.V.; Wessling, Matthias

    2005-01-01

    This paper studies the mass transport properties for water vapor and nitrogen for a series of poly(ethylene oxide) (PEO) poly(butylene terephthalate) (PBT) multi-block copolymers via: (a) the permeation of a water vapor/N2 mixture (b) the sorption of water vapor, (c) the diffusion of water vapor, (d

  5. Release of anti-restenosis drugs from poly(ethylene oxide)-poly (DL-lactic-co-glycolic acid) nanoparticles

    NARCIS (Netherlands)

    Zweers, M.L.T.; Engbers, G.H.M.; Grijpma, Dirk W.; Feijen, Jan

    2007-01-01

    Dexamethasone- or rapamycin-loaded nanoparticles based on poly(ethylene oxide) and poly(dl-lactic-co-glycolic acid) block copolymers (PEO-PLGA) were prepared without additional stabilizer using the salting-out method. A fast release of drug in PBS (pH 7.4) at 37 °C resulting in 100% release within 5

  6. Synthesis of α-hydroxy-ω-amino poly(ethylene oxide) and its use in reaction injection moulding (RIM)

    NARCIS (Netherlands)

    Loontjens, Ton J.A.; Scholtens, Boudewijn J.R.; Belt, Wil J.W.; Frisch, Kurt C.; Wong, Shaio-wen

    1993-01-01

    Computer simulations show that oligomers with two different terminal groups with dissimilar reactivities for isoeyanates give a delayed viscosity rise in polyurethanes. This is a desired behaviour for RIM processes. Therefore, an α-hydroxy-ω-amino poly(ethylene oxide) (HAPEO) has been prepared. The

  7. Release of anti-restenosis drugs from poly(ethylene oxide)-poly(dl-lactic-co-glycolic acid) nanoparticles

    NARCIS (Netherlands)

    Zweers, Miechel L.T.; Engbers, Gerard H.M.; Grijpma, Dirk W.; Feijen, Jan

    2006-01-01

    Dexamethasone- or rapamycin-loaded nanoparticles based on poly(ethylene oxide) and poly(dl-lactic-co-glycolic acid) block copolymers (PEO-PLGA) were prepared without additional stabilizer using the salting-out method. A fast release of drug in PBS (pH 7.4) at 37 °C resulting in 100% release within 5

  8. Synthesis of α-hydroxy-ω-amino poly(ethylene oxide) and its use in reaction injection moulding (RIM)

    NARCIS (Netherlands)

    Loontjens, Ton J.A.; Scholtens, Boudewijn J.R.; Belt, Wil J.W.; Frisch, Kurt C.; Wong, Shaio-wen

    1993-01-01

    Computer simulations show that oligomers with two different terminal groups with dissimilar reactivities for isoeyanates give a delayed viscosity rise in polyurethanes. This is a desired behaviour for RIM processes. Therefore, an α-hydroxy-ω-amino poly(ethylene oxide) (HAPEO) has been prepared. The

  9. Microscopic muon dynamics in the polymer electrolyte poly(ethylene oxide)

    Science.gov (United States)

    McKenzie, Iain; Cottrell, Stephen P.

    2017-07-01

    The microscopic dynamics of protons (H+) in poly(ethylene oxide) (PEO) have been investigated through a study of implanted positive muons (Mu+), which can be considered a light proton analog. The exponential decay of the muon spin polarization in zero magnetic field indicated that Mu+ hopping is in the fast fluctuation limit between 140 and 310 K and the relaxation rate was found to be sensitive to the glass transition. Mu+ dynamics in PEO was monitored via the relaxation of the muon spin polarization in a transverse field of 10 mT. Activated hopping of Mu+ was observed above the glass transition temperature with an activation barrier of 122 ±1 meV. The temperature dependence of the diamagnetic muon polarization in PEO can be explained by diffusion of radiolytic electrons.

  10. A Polarizable Potential for Poly(ethylene oxide) in Aqueous Solution

    Science.gov (United States)

    Starovoytov, Oleg; Borodin, Oleg; Bedrov, Dmitry; Smith, Grant

    2010-03-01

    We have developed a quantum chemistry-based polarizable potential for poly(ethylene oxide) (PEO) in aqueous solution based on the APPLE&P polarizable ether and SWM4-DP polarizable water model. Ether-water interactions were parameterized to reproduce the binding energy of water with 1,2-dimethoxyethane (DME) determined from high-level quantum chemistry calculations. Simulations of DME/water and PEO/water solutions at room temperature using the new polarizable potential yielded thermodynamic and transport properties in better agreement with experiment than previously published polarizable and non-polarizable potentials. The predicted miscibility of PEO and water as a function of temperature was found to be strongly correlated with the predicted free energy of solvation of DME in water for the various force fields investigated. Simulations of PEO/water solutions confirm the ability of the new potential to capture, at least qualitatively, the LCST behavior of these solutions

  11. Conformation and hydration of surface grafted and free polyethylene oxide chains in solutions

    Science.gov (United States)

    Dahal, Udaya; Wang, Zilu; Dormidontova, Elena

    Due to the wide application of polyethylene oxide (PEO), ranging from biomedicine to fuel cells, it is one of the most studied polymers in the scientific world. In order to elucidate detailed molecular-level insights on the impact of surface grafting on PEO conformation, we performed atomistic molecular dynamics simulations of PEO chains in solution and grafted to a flat gold surface in different solvents. We examined the hydration as well as conformation of the free chain compared to the grafted polymer in pure water and mixed solvents. We find that grafted chains are stiffer and have a stronger tendency to form helical structures in isobutyric acid or mixture of isobutyric acid and water solution than the free chains in corresponding solutions. For grafted chains exposed to pure water the random coil conformation is retained at low grafting density, but becomes stretched and more dehydrated as the grafting density or temperature increases. This research is supported by NSF (DMR-1410928).

  12. Poly(ethylene oxide)/clay nanaocomposites: Thermal and mechanical properties

    Science.gov (United States)

    Ejder-Korucu, Mehtap; Gürses, Ahmet; Karaca, Semra

    2016-08-01

    Poly(ethylene oxide) (PEO)/clay nanocomposites were prepared by a solution intercalation method using chloroform as a solvent. The nanocomposites were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and also investigation of some mechanical properties of the composites. Formation of nanocomposite was confirmed by XRD analysis. The increasing tendency of exfoliation degree with an increase in clay content may be attributed to easier diffusion of PEO chains to interlayer regions. An increase in PEO crystallinity in case of nanocomposite, was confirmed by an increase in the heat of melting as indicated by DSC. Improvement in tensile properties in all respect was observed for nanocomposites with clay content.

  13. Effects of Silica Nanostructures in Poly(ethylene oxide)-Based Composite Polymer Electrolytes.

    Science.gov (United States)

    Mohanta, Jagdeep; Anwar, Shahid; Si, Satyabrata

    2016-06-01

    The present work describes the synthesis of some poly(ethylene oxide)-based nanocomposite polymer electrolyte films using various silica nanostructures as the inorganic filler by simple solution mixing technique, in which the nature of the silica nanostructures play a vital role in modulating their electrochemical performances at room temperature. The silica nanostructures are prepared by ammonical hydrolysis of tetraethyl orthosilicate following the modified St6ber method. The resulting films are characterized by X-ray diffraction and differential scanning calorimeter to study their crystallinity. Room temperature AC impedance spectroscopy is utilized to determine the Li+ ion conductivity of the resulting films. The observed conductivity values of various NCPE films depend on the nature of silica filling as well as on their surface characteristics and also on the varying PEO-Li+ ratio, which is observed to be in the order of 10(-7)-10(-6) S cm(-1).

  14. Accumulation of magnetic iron oxide nanoparticles coated with variably sized polyethylene glycol in murine tumors.

    Science.gov (United States)

    Larsen, Esben Kjær Unmack; Nielsen, Thomas; Wittenborn, Thomas; Rydtoft, Louise Munk; Lokanathan, Arcot R; Hansen, Line; Østergaard, Leif; Kingshott, Peter; Howard, Kenneth A; Besenbacher, Flemming; Nielsen, Niels Chr; Kjems, Jørgen

    2012-04-07

    Iron oxide nanoparticles have found widespread applications in different areas including cell separation, drug delivery and as contrast agents. Due to water insolubility and stability issues, nanoparticles utilized for biological applications require coatings such as the commonly employed polyethylene glycol (PEG). Despite its frequent use, the influence of PEG coatings on the physicochemical and biological properties of iron nanoparticles has hitherto not been studied in detail. To address this, we studied the effect of 333-20,000 Da PEG coatings that resulted in larger hydrodynamic size, lower surface charge, longer circulation half-life, and lower uptake in macrophage cells when the particles were coated with high molecular weight (M(w)) PEG molecules. By use of magnetic resonance imaging, we show coating-dependent in vivo uptake in murine tumors with an optimal coating M(w) of 10,000 Da.

  15. Molecular Dynamics Simulations of Silica Nanoparticles Grafted with Poly(ethylene oxide) Oligomer Chains

    KAUST Repository

    Hong, Bingbing

    2012-03-01

    A molecular model of silica nanoparticles grafted with poly(ethylene oxide) oligomers has been developed for predicting the transport properties of nanoparticle organic-hybrid materials (NOHMs). Ungrafted silica nanoparticles in a medium of poly(ethylene oxide) oligomers were also simulated to clarify the effect of grafting on the dynamics of nanoparticles and chains. The model approximates nanoparticles as solid spheres and uses a united-atom representation for chains, including torsional and bond-bending interactions. The calculated viscosities from Green-Kubo relationships and temperature extrapolation are of the same order of magnitude as experimental data but show a smaller activation energy relative to real NOHMs systems. Grafted systems have higher viscosities, smaller diffusion coefficients, and slower chain dynamics than the ungrafted ones at high temperatures. At lower temperatures, grafted systems exhibit faster dynamics for both nanoparticles and chains relative to ungrafted systems, because of lower aggregation of particles and enhanced correlations between nanoparticles and chains. This agrees with the experimental observation that NOHMs have liquidlike behavior in the absence of a solvent. For both grafted and ungrafted systems at low temperatures, increasing chain length reduces the volume fraction of nanoparticles and accelerates the dynamics. However, at high temperatures, longer chains slow down nanoparticle diffusion. From the Stokes-Einstein relationship, it was determined that the coarse-grained treatment of nanoparticles leads to slip on the nanoparticle surfaces. Grafted systems obey the Stokes-Einstein relationship over the temperature range simulated, but ungrafted systems display deviations from it. © 2012 American Chemical Society.

  16. OPTIMIZATION AND CHARACTERIZATION OF POLYSULFONE MEMBRANES MADE OF ZINC OXIDE, POLYETHYLENE GLYCOL AND EUGENOL AS ADDITIVES

    Directory of Open Access Journals (Sweden)

    MUHAMAD ZAINI YUNOS

    2016-07-01

    Full Text Available The aim of this study to investigate the effect of zinc oxide, polyethylene glycol (PEG and eugenol on the properties of membranes made of polysulfone (PSf. Polysulfone membranes were prepared via phase inversion method using Nmethyl-2-pyrolidone (NMP as a solvent and water as non-solvent. The membranes were characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD, atomic force microscopy (AFM, porosity, tensile strength, permeability, rejection and antibacterial test. The results were designed and optimized through a statistical approach using response surface methodology (RSM. The results showed that the use of zinc oxide and eugenol could improve membrane rejection and anti-bacterial property. The membrane permeability was found to increase with addition of PEG. The optimized dope formulation for maximum membrane permeability and rejection was found at 13.14 wt.% PEG 5 wt.% zinc oxide and 0.17 wt.% eugenol. The permeability and rejection obtained for actual value is 866 L m-2h-1 and 91.0% respectively, which 1 and 2% difference compared to the predicted value.

  17. Convenient synthesis of heterobifunctional poly(ethylene glycol) suitable for the functionalization of iron oxide nanoparticles for biomedical applications

    OpenAIRE

    Passemard, Solène; Städler, Davide; Ucnova, Lucia; Schneiter, Guillaume Stéphane; Kong, Phally; Bonacina, Luigi; Gerber-Lemaire, Sandrine

    2013-01-01

    A straightforward route is proposed for the multi-gram scale synthesis of heterobifunctional poly(ethylene glycol) (PEG) oligomers containing combination of triethyloxysilane extremity for surface modification of metal oxides and amino or azido active end groups for further functionalization. The suitability of these PEG derivatives to be conjugated to nanomaterials was shown by pegylation of ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles (NPs), followed by functionalization wi...

  18. Syntheses, characterization and adsorption properties for Pb{sup 2+} of silica-gel functionalized by dendrimer-like polyamidoamine and 5-sulfosalicylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Xiongzhi, E-mail: 2004046@glut.edu.cn; Luo, Liangliang; Chen, Ziyan; Liang, Kailing

    2016-02-28

    Graphical abstract: SEM images of APSG, PAMAM-1.0SSASG, PAMAM-2.0SSASG, PAMAM-3.0SSASG and PAMAM-4.0SSASG. - Highlights: • Silica-gel adsorbents PAMAM-n.0SSASG (n = 1–4) with dendrimer-like polyamidoamine and 5-sulfosalicylic acid as functional groups were prepared. • The generation increase of grafted PAMAM changed the pore diameter distribution of adsorbent and adsorption/desorption property of PAMAM-4.0SSASG for Pb{sup 2+} was the best of four adsorbents. • The priority of adsorption property of PAMAM-4.0SSASG was explained by steric hindrance effect of PAMAM on adsorption/desorption, and selective adsorption of 5-sulfosalicylic acid with Pb{sup 2+}. • Pb{sup 2+} in standard reference sample and sea water sample were preconcentrated with PAMAM-4.0SSASG as adsorbent and determined by GFAAS. - Abstract: Silica-gel adsorbents PAMAM-n.0SSASG (n = 1–4) with dendrimer-like polyamidoamine (PAMAM) and 5-sulfosalicylic acid as functional groups were prepared and characterized with FTIR, SEM, TG, elemental analysis and porous structure analysis. Micro-column enrichment and measurement of Pb{sup 2+} with graphite furnace atomic absorption spectroscopy (GFAAS) was studied with PAMAM-n.0SSASG (n = 1–4) as adsorbent. It was emphasized to investigate the relationship between dynamic adsorption/desorption rates, adsorption capacities, and grafting percentage of PAMAM onto silica-gel surface. Experiments showed that the generation increase of grafted PAMAM changed the pore diameter distribution of adsorbent and obviously improved adsorption/desorption property for Pb{sup 2+}. Adsorption capacity of PAMAM-n.0SSASG (n = 1–4) was 14.04, 17.43, 20.07 and 25.05 mg g{sup −1} for Pb{sup 2+} respectively. An enrichment factor of 200 was obtained with PAMAM-4.0SSASG as adsorbent and with 2000 mL Pb{sup 2+} solution (1.0 ng mL{sup −1}). The priority of adsorption property of PAMAM-4.0SSASG was explained by steric hindrance effect of PAMAM on adsorption/desorption, and

  19. Poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide)-templated synthesis of mesoporous alumina: effect of triblock copolymer and acid concentration.

    Science.gov (United States)

    Materna, Kelly L; Grant, Stacy M; Jaroniec, Mietek

    2012-07-25

    Mesoporous alumina was synthesized via a one-pot self-assembly of aluminum isopropoxide and poly(ethylene oxide)-poly(butylene oxide)-poly(ethylene oxide) triblock copolymer in an acidic ethanol solution. The effects of the polymer concentration and nitric acid concentration, independently, on the adsorption properties (such as surface area, pore volume, microporosity, mesoporosity, and pore width) were studied. An increase in the specific surface area and the pore volume was seen for the samples containing a polymer/aluminum isopropoxide wt. ratio up to 0.71 and a polymer/acid wt ratio of 0.88. Titania isopropoxide was also added to the synthesis to illustrate the extension of this approach to alumina-based mixed metal oxides.

  20. Synthesis, characterization, and in vivo evaluation of poly(ethylene oxide-co-glycidol)-platinate conjugate.

    Science.gov (United States)

    Zhou, Ping; Li, Zhongyu; Chau, Ying

    2010-11-20

    Poly(ethylene oxide-co-glycidol) (poly(EO-co-Gly)), a member of polyether polyol (PEP), resembles polyethylene glycol (PEG) in the polymer backbone but distinguishes itself by having multiple pendent groups along the main chain. We showed that this new bioconjugation material is biocompatible by its lack of toxicity on fibroblast cell growth, inactivity in hemolysis, and the absence of side effects after injection in mice. The usefulness of poly(EO-co-Gly) as a polymeric drug carrier was demonstrated via the preparation and characterization of a new anticancer polymer-drug conjugate, poly(EO-co-Gly)-platinate. The drug loading was 9.1-12.6% (cisplatin/conjugate w/w), at least four times higher than a PEG conjugate of similar molecular weight. The aqueous solubility of cisplatin was increased by around 10 folds after conjugation. Platinum complexes were released from the conjugate in a sustained manner over 2 days. The release of active drugs was confirmed by the antitumor activity of poly(EO-co-Gly)-platinate in vitro against HONE-1 (human nasopharyngeal carcinoma) and MCF-7 (human breast cancer), albeit at a potency lower than free cisplatin. Poly(EO-co-Gly)-platinate improved the therapeutic index of cisplatin in vivo. The conjugate had a similar antitumor activity as free cisplatin in nude mice bearing HONE-1 xenografts, and achieved 52% inhibition of tumor growth at the conclusion of the study. While free cisplatin injection caused a severe loss in body weight (>20%), poly(EO-co-Gly)-platinate resulted in mild side effects. These findings support that poly(EO-co-Gly) is a suitable drug carrier.

  1. Covalent functionalization of graphene oxide with biocompatible poly(ethylene glycol) for delivery of paclitaxel.

    Science.gov (United States)

    Xu, Zhiyuan; Wang, Song; Li, Yongjun; Wang, Mingwei; Shi, Ping; Huang, Xiaoyu

    2014-10-08

    Graphene oxide (GO), a novel 2D nanomaterial prepared by the oxidation of natural graphite, has been paid much attention in the area of drug delivery due to good biocompatibility and low toxicity. In the present work, 6-armed poly(ethylene glycol) was covalently introduced into the surface of GO sheets via a facile amidation process under mild conditions, making the modified GO, GO-PEG (PEG: 65 wt %, size: 50-200 nm), stable and biocompatible in physiological solution. This nanosized GO-PEG was found to be nontoxic to human lung cancer A549 and human breast cancer MCF-7 cells via cell viability assay. Furthermore, paclitaxel (PTX), a widely used cancer chemotherapy drug, was conjugated onto GO-PEG via π-π stacking and hydrophobic interactions to afford a nanocomplex of GO-PEG/PTX with a relatively high loading capacity for PTX (11.2 wt %). This complex could quickly enter into A549 and MCF-7 cells evidenced by inverted fluorescence microscopy using Fluorescein isothiocyanate as a probe, and it also showed remarkably high cytotoxicity to A549 and MCF-7 cells in a broad range of concentration of PTX and time compared to free PTX. This kind of nanoscale drug delivery system on the basis of PEGylated GO may find potential application in biomedicine.

  2. Oxidized Polyethylene Wax as a Potential Carbon Source for PHA Production

    Directory of Open Access Journals (Sweden)

    Iza Radecka

    2016-05-01

    Full Text Available We report on the ability of bacteria to produce biodegradable polyhydroxyalkanoates (PHA using oxidized polyethylene wax (O-PEW as a novel carbon source. The O-PEW was obtained in a process that used air or oxygen as an oxidizing agent. R. eutropha H16 was grown for 48 h in either tryptone soya broth (TSB or basal salts medium (BSM supplemented with O-PEW and monitored by viable counting. Study revealed that biomass and PHA production was higher in TSB supplemented with O-PEW compared with TSB only. The biopolymers obtained were preliminary characterized by nuclear magnetic resonance (NMR, gel permeation chromatography (GPC, differential scanning calorimetry (DSC, and thermogravimetric analysis (TGA. The detailed structural evaluation at the molecular level was performed by electrospray ionization tandem mass spectrometry (ESI-MS/MS. The study revealed that, when TSB was supplemented with O-PEW, bacteria produced PHA which contained 3-hydroxybutyrate and up to 3 mol % of 3-hydroxyvalerate and 3-hydroxyhexanoate co-monomeric units. The ESI-MS/MS enabled the PHA characterization when the content of 3-hydroxybutyrate was high and the appearance of other PHA repeating units was very low.

  3. Oxygen Barrier Properties and Melt Crystallization Behavior of Poly(ethylene terephthalate/Graphene Oxide Nanocomposites

    Directory of Open Access Journals (Sweden)

    Anna Szymczyk

    2015-01-01

    Full Text Available Poly(ethylene terephthalate nanocomposites with low loading (0.1–0.5 wt% of graphene oxide (GO have been prepared by using in situ polymerization method. TEM study of nanocomposites morphology has shown uniform distribution of highly exfoliated graphene oxide nanoplatelets in PET matrix. Investigations of oxygen permeability of amorphous films of nanocomposites showed that the nanocomposites had better oxygen barrier properties than the neat PET. The improvement of oxygen permeability for PET nanocomposite films over the neat PET is approximately factors of 2–3.3. DSC study on the nonisothermal crystallization behaviors proves that GO acts as a nucleating agent to accelerate the crystallization of PET matrix. The evolution of the lamellar nanostructure of nanocomposite and neat PET was monitored by SAXS during nonisothermal crystallization from the melt. It was found that unfilled PET and nanocomposite with the highest concentration of GO (0.5 wt% showed almost similar values of the long period (L=11.4 nm for neat PET and L=11.5 nm for PET/0.5GO.

  4. Steric stabilization of microspheres with grafted polyethylene oxide reduces phagocytosis by rat Kupffer cells in vitro.

    Science.gov (United States)

    Harper, G R; Davies, M C; Davis, S S; Tadros, T F; Taylor, D C; Irving, M P; Waters, J A

    1991-09-01

    Sterically stabilized polyethylene oxide-polystyrene copolymer microspheres, (PS-PEO) and charge stabilized polystyrene (PS) microspheres of similar size (1 micron) were prepared in order to compare their uptake by cultured rat Kupffer cells isolated by centrifugal elutriation. The uptake of the sterically stabilized particles was found to be much less than that for the charge stabilized control. The uptake of microspheres stabilized with covalently grafted PEO was lower or equivalent to that of control microspheres stabilized by the adsorption of the non-ionic PEO-polypropylene oxide (PPO-PEO) surfactant Poloxamer 238 or Methoxy-PEO. Phagocytic uptake by Kupffer cells at low and body temperature (8 degrees C and 37 degrees C) demonstrated that PS-PEO particles showed both low adherence and low metabolic uptake. The adsorption of PEO, as Poloxamer 238, to particles with covalently attached or grafted PEO resulted in a synergistic reduction in uptake that was greater than the individual effects of grafting and adsorption alone (P less than or equal to 0.001). It is suggested that this combination produces a more effective steric barrier on the particle surface with the Poloxamer adsorbing to the surface between the grafted PEO chains. The relevance to drug targeting/carrier systems is discussed.

  5. The evaluation of physical properties of injection molded systems based on poly(ethylene oxide) (PEO).

    Science.gov (United States)

    Pajander, Jari; Rensonnet, Alexia; Hietala, Sami; Rantanen, Jukka; Baldursdottir, Stefania

    2017-02-25

    The effect of product design parameters on the formation and properties of an injection molded solid dosage form consisting of poly(ethylene oxide)s (PEO) and two different active pharmaceutical ingredients (APIs) was studied. The product design parameters explored were melting temperature and the duration of melting, API loading degree and the molecular weight (Mw) of PEO. The solid form composition of the model APIs, theophylline and carbamazepine, was of specific interest, and its possible impact on the in vitro drug release behavior. Mw of PEO had the greatest impact on the release rate of both APIs. High Mw resulted in slower API release rate. Process temperature had two-fold effect with PEO 300,000g/mol. Firstly, higher process temperature transformed the crystalline part of the polymer into metastable folded form (more folded crystalline regions) and less into the more stable extended form (more extended crystalline regions), which lead to enhanced theophylline release rate. Secondly, the higher process temperature seemed to induce carbamazepine polymorphic transformation from p-monoclinic form III (carbamazepine (M)) into trigonal form II (carbamazepine (T)). The results indicated that the actual content of carbamazepine (T) affected drug release behavior more than the magnitude of transformation.

  6. Confinement effects on the crystallization of poly(ethylene oxide) nanotubes.

    Science.gov (United States)

    Maiz, Jon; Martin, Jaime; Mijangos, Carmen

    2012-08-21

    In this work, we show the effects of nanoconfinement on the crystallization of poly(ethylene oxide) (PEO) nanotubes embedded in anodized aluminum oxide (AAO) templates. The morphological characteristics of the hollow 1D PEO nanostructures were evaluated by scanning electron microscopy (SEM). The crystallization of the PEO nanostructures and bulk was studied with differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD). The crystallization of PEO nanotubes studied by DSC is strongly influenced by the confinement showing a strong reduction in the crystallization temperature of the polymer. X-ray diffraction (XRD) experiments confirmed the isothermal crystallization results obtained by DSC, and studies carried out at low temperatures showed the absence of crystallites oriented with the extended chains perpendicular to the pore wall within the PEO nanotubes, which has been shown to be the typical crystal orientation for one-dimensional polymer nanostructures. In contrast, only planes oriented 33, 45, and 90° with respect to the plane (120) are arranged parallel to the pore's main axis, indicating preferential crystal growth in the direction of the radial component. Calculations based on classical nucleation theory suggest that heterogeneous nucleation prevails in the bulk PEO whereas for the PEO nanotubes a surface nucleation mechanism is more consistent with the obtained results.

  7. CONDUCTING BLENDS OF POLY(2-VINYL PYRIDINE) AND POLYETHYLENE OXIDE WITH HIGH MOLECULAR WEIGHT

    Institute of Scientific and Technical Information of China (English)

    CUI Minhui; GUO Junshi; XIE Hongquan; CHENG Donghua

    1997-01-01

    Ionic, electronic and mixed (ionic-electronic) conductivities of blends of poly(2-vinyl pyridine) (P2VP) and poly(ethylene oxide) (PEO) with high molecular weight after doped with LiClO4, TCNQ or LiClO4 and TCNQ were investigated. Effects of LiClO4 and TCNQ concentrations on the conductivity of PEO/P2VP/LiClO4 or TCNQ blend were studied.The ionic conductivity of PEO/P2VP/LiClO4 blend increases with increasing PEO content.At a Li/ethylene oxide molar ratio of 0.10 and a TCNQ/2-vinyl pyridine molar ratio of 0.5,the mixed conductivity of PEO/P2VP/LiClO4/TCNQ is higher than the total of ionic conductivity of PEO/P2VP/LiClO4 and electronic conductivity of PEO/P2VP/TCNQ when the weight ratio of PEO and P2VP is 6/4 or 5/5. Scanning electron microscopy (SEM) on the broken cross-section of the PEO/P2VP/LiClO4 blend and differential scanning calorimetry (DSC) results show that LiClO4 could act as a compatibilizer in the blend.

  8. Electrochemical oxidation of polyethylene glycol in electroplating solution using paraffin composite copper hexacyanoferrate modified (PCCHM) anode.

    Science.gov (United States)

    Bejankiwar, Rajesh S; Basu, Abir; Cementi, Max

    2004-01-01

    Electrochemical oxidation of polyethylene glycol (PEG) in an acidic (pH 0.18 to 0.42) and high ionic strength electroplating solution was investigated. The electroplating solution is a major source of wastewater in the printing wiring board industry. A paraffin composite copper hexacyanoferrate modified (PCCHM) electrode was used as the anode and a bare graphite electrode was used as the cathode. The changes in PEG and total organic carbon (TOC) concentrations during the course of the reaction were monitored. The efficiency of the PCCHM anode was compared with bare graphite anode and it was found that the former showed significant electrocatalytic property for PEG and TOC removal. Chlorides present in the solution were found to contribute significantly in the overall organic removal process. Short chain organic compounds like acetic acid, oxalic acid, formic acid and ethylene glycol formed during electrolysis were identified by HPLC method. Anode surface area and applied current density were found to influence the electro-oxidation process, in which the former was found to be dominating. Investigations of the kinetics for the present electrochemical reaction suggested that the two stage first-order kinetic model provides a much better representation of the overall mechanism of the process if compared to the generalized kinetic model.

  9. Electrochemical oxidation of polyethylene glycol in electroplating solution using paraffin composite copper hexacyanoferrate modified (PCCHM) anode

    Institute of Scientific and Technical Information of China (English)

    Rajesh S. Bejankiwar; Abir Basu; Max Cementi

    2004-01-01

    Electrochemical oxidation of polyethylene glycol(PEG) in an acidic(pH 0.18 to 0.42) and high ionic strength electroplating solution was investigated. The electroplating solution is a major source of wastewater in the printing wiring board industry. A paraffin composite copper hexacyanoferrate modified(PCCHM) electrode was used as the anode and a bare graphite electrode was used as the cathode. The changes in PEG and total organic carbon(TOC) concentrations during the course of the reaction were monitored. The efficiency of the PCCHM anode was compared with bare graphite anode and it was found that the former showed significant electrocatalytic property for PEG and TOC removal. Chlorides present in the solution were found to contribute significantly in the overall organic removal process. Short chain organic compounds like acetic acid, oxalic acid, formic acid and ethylene glycol formed during electrolysis were identified by HPLC method. Anode surface area and applied current density were found to influence the electro-oxidation process, in which the former was found to be dominating. Investigations of the kinetics for the present electrochemical reaction suggested that the two stage first-order kinetic model provides a much better representation of the overall mechanism of the process if compared to the generalized kinetic model.

  10. Low-cost flexible supercapacitors based on laser reduced graphene oxide supported on polyethylene terephthalate substrate

    Science.gov (United States)

    Ghoniem, Engy; Mori, Shinsuke; Abdel-Moniem, Ahmed

    2016-08-01

    A controlled high powered CO2 laser system is used to reduce and pattern graphene oxide (GO) film supported onto a flexible polyethylene terephthalate (PET) substrate. The laser reduced graphene oxide (rGO) film is characterized and evaluated electrochemically in the absence and presence of an overlying anodicaly deposited thin film of pseuodcapactive MnO2 as electrodes for supercapacitor applications using aqueous electrolyte. The laser treatment of the GO film leads to an overlapped structure of defective multi-layer rGO sheets with an electrical conductivity of 273 S m-1. The rGO and MnO2/rGO electrodes exhibit specific capacitance in the range of 82-107 and 172-368 Fg-1 at applied current range of 0.1-1.0 mA cm-2 and retain 98 and 95% of their initial capacitances after 2000 cycles at a current density of 1.0 mA cm-2, respectively. Also, the rGO is assigned as an electrode material for flexible conventionally stacked and interdigitated in-plane supercapacitor structures using gel electrolyte. Three electrode architectures of 2, 4, and 6 sub-electrodes are studied for the interdigital in-plane design. The device with interdigital 6 sub-electrodes architecture I-PS(6) delivers power density of 537.1 Wcm-3 and an energy density of 0.45 mWh cm-3.

  11. Graphene oxide functionalized with silver@silica-polyethylene glycol hybrid nanoparticles for direct electrochemical detection of quercetin.

    Science.gov (United States)

    Veerapandian, Murugan; Seo, Yeong-Tai; Yun, Kyusik; Lee, Min-Ho

    2014-08-15

    A direct electrochemical detection of quercetin based on functionalized graphene oxide modified on gold-printed circuit board chip was demonstrated in this study. Functionalized graphene oxide materials are prepared by the covalent reaction of graphene oxide with silver@silica-polyethylene glycol nanoparticles (~12.35nm). Functionalized graphene oxide electrode shows a well-defined voltammetric response in phosphate buffered saline and catalyzes the oxidation of quercetin to quinone without the need of an enzyme. Significantly, the functionalized graphene oxide modified electrode exhibited a higher sensitivity than pristine gold-printed circuit board and graphene oxide electrodes, a wide concentration range of 7.5 to 1040nM and detection limit of 3.57nM. Developed biosensor platform is selective toward quercetin in the presence of an interferent molecule.

  12. Synthesis of Upconverting Hydrogel Nanocomposites Using Thiol-Ene Click Chemistry: Template for the Formation of Dendrimer-Like Gold Nanoparticle Assemblies.

    Science.gov (United States)

    Meesaragandla, Brahmaiah; Mahalingam, Venkataramanan

    2015-11-16

    The synthesis of upconverting hydrogel nanocomposites by base-catalyzed thiol-ene click reaction between 10-undecenoic acid capped Yb(3+)/Er(3+)-doped NaYF4 nanoparticles and pentaerythritol tetrakis(3-mercaptopropionate) (PETMP) as tetrathiol monomer is reported. This synthetic strategy for nanocomposite gels is quite different from works where usually the preformed gels are mixed with the nanoparticles. Developing nanocomposites by surface modification of capping ligands would allow tuning and controlling of the separation of the nanoparticles inside the gel network. The hydrogel nanocomposites prepared by thiol-ene click reaction show strong enhancement in luminescence intensity compared to 10-undecenoic acid-capped Yb(3+)/Er(3+)-doped NaYF4 nanoparticles through the upconversion process (under 980 nm laser excitation). The hydrogel nanocomposites display strong swelling characteristics in water resulting in porous structures. Interestingly, the resulting nanocomposite gels act as templates for the synthesis of dendrimer-like Au nanostructures when HAuCl4 is reduced in the presence of the nanocomposite gels.

  13. Fabrication and anti-fouling properties of photochemically and thermally immobilized poly(ethylene oxide) and low molecular weight poly(ethylene glycol) thin films.

    Science.gov (United States)

    Wang, Hui; Ren, Jin; Hlaing, Aye; Yan, Mingdi

    2011-02-01

    Poly(ethylene oxide) (PEO) and low molecular weight poly(ethylene glycol) (PEG) were covalently immobilized on silicon wafers and gold films by way of the CH insertion reaction of perfluorophenyl azides (PFPAs) by either photolysis or thermolysis. The immobilization does not require chemical derivatization of PEO or PEG, and polymers of different molecular weights were successfully attached to the substrate to give uniform films. Microarrays were also generated by printing polymer solutions on PFPA-functionalized wafer or Au slides followed by light activation. For low molecular weight PEG, the immobilization was highly dependent on the quality of the film deposited on the substrate. While the spin-coated and printed PEG showed poor immobilization efficiency, thermal treatment of the PEG melt on PFPA-functionalized surfaces resulted in excellent film quality, giving, for example, a grafting density of 9.2×10(-4)Å(-2) and an average distance between grafted chains of 33Å for PEG 20,000. The anti-fouling property of the films was evaluated by fluorescence microscopy and surface plasmon resonance imaging (SPRi). Low protein adsorption was observed on thermally-immobilized PEG whereas the photoimmobilized PEG showed increased protein adsorption. In addition, protein arrays were created using polystyrene (PS) and PEG based on the differential protein adsorption of the two polymers.

  14. Self-consistent-field analysis of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) surfactants: micellar structure, critical micellization concentration, critical micellization temperature, and cloud point

    NARCIS (Netherlands)

    Bruijn, de V.G.; Broeke, van den L.J.P.; Leermakers, F.A.M.; Keurentjes, J.T.F.

    2002-01-01

    The self-assembly of a series of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) surfactants into spherical micelles has been analyzed by a numerical self-consistent-field model. A united atom description is used in which three segment types are identified, that is,

  15. Self-consistent-field analysis of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) surfactants: micellar structure, critical micellization concentration, critical micellization temperature, and cloud point

    NARCIS (Netherlands)

    Bruijn, de V.G.; Broeke, van den L.J.P.; Leermakers, F.A.M.; Keurentjes, J.T.F.

    2002-01-01

    The self-assembly of a series of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) surfactants into spherical micelles has been analyzed by a numerical self-consistent-field model. A united atom description is used in which three segment types are identified, that is, CH2

  16. Synthesis of novel bis(perfluorophenyl azides) coupling agents: Evaluation of their performance by crosslinking of poly(ethylene oxide)

    KAUST Repository

    Mehenni, Hakim

    2011-11-01

    Novel bis(perfluorophenyl azides) coupling agents, containing spacer arms from ethylene or ethylene glycol subunits, were successfully synthesized. Nitrenes photogenerated from these novel bis(PFPA) coupling agents were applied successfully to the cross-linking of poly(ethylene oxide) (PEO10,000) in either aqueous medium or at the solid state, thus, we demonstrated the potential of these bis(PFPA) molecules as promising coupling agents in surface engineering. © 2011 Elsevier Ltd. All rights reserved.

  17. In vitro degradation of nanoparticles prepared from polymers based on DL-lactide, glycolide and poly(ethylene oxide)

    NARCIS (Netherlands)

    Zweers, M.L.T.; Engbers, G.H.M.; Grijpma, Dirk W.; Feijen, Jan

    2004-01-01

    Nanoparticles of poly(DL-lactic acid) (PDLLA), poly(DL-lactic-co-glycolic acid) (PLGA) and poly(ethylene oxide)–PLGA diblock copolymer (PEO–PLGA) were prepared by the salting-out method. The in vitro degradation of PDLLA, PLGA and PEO–PLGA nanoparticles in PBS (pH 7.4) at 37 °C was studied. The

  18. Adhesion mapping of chemically modified and poly(ethylene oxide)-grafted glass surfaces

    Science.gov (United States)

    Jogikalmath, G.; Stuart, J.K.; Pungor, A.; Hlady, V.

    2012-01-01

    Two-dimensional mapping of the adhesion pull-off forces was used to study the origin of surface heterogeneity in the grafted poly(ethylene oxide) (PEO) layer. The variance of the pull-off forces measured over the μm-sized regions after each chemical step of modifying glass surfaces was taken to be a measure of the surface chemical heterogeneity. The attachment of γ-glycidoxypropyltrimethoxy silane (GPS) to glass decreased the pull-off forces relative to the clean glass and made the surface more uniform. The subsequent hydrolysis of the terminal epoxide groups resulted in a larger surface heterogeneity which was modeled by two populations of the terminal hydroxyl groups, each with its own distribution of adhesion forces and force variance. The activation of the hydroxyls with carbonyldiimmidazole (CDI) healed the surface and lowered its adhesion, however, the force variance remained rather large. Finally, the grafting of the α,ω-diamino poly(ethyleneoxide) chains to the CDI-activated glass largely eliminated adhesion except at a few discrete regions. The adhesion on the PEO grafted layer followed the Poisson distribution of the pull-off forces. With the exception of the glass surface, a correlation between the water contact angles and the mean pull-off forces measured with the Si3N4 tip surfaces was found for all modified glass surfaces. PMID:22267896

  19. Thermal properties of poly(ethylene oxide)/lauric acid blends. A SSA-DSC study

    Energy Technology Data Exchange (ETDEWEB)

    Pielichowski, Krzysztof; Flejtuch, Kinga [Department of Chemistry and Technology of Polymers, Cracow University of Technology, ul. Warszawska 24, 31-155 Krakow (Poland)

    2006-03-15

    A series of poly(ethylene oxide) (PEO)/lauric acid blends with different compositions has been prepared and characterised by differential scanning calorimetry (DSC) in dynamic mode. It has been found that the enthalpy of melting and crystallisation reaches its highest value for PEO/lauric acid blend (1:1, w/w) which makes this system a promising candidate for thermal energy storage applications. Further studies by step-scan alternating (SSA)-DSC revealed that an increase of the temperature step causes that the average total heating rate is also increasing and the heat flow is characterised by higher values. Reversing component of the heat flow during melting reaches lowest values at highest step (step=1{sup o}) when the re-crystallisation of PEO is hindered. An increase of step generally leads to an increase of the number of non-equilibrium effects and facilitates the activation of kinetic non-reversing processes, hindering the overall crystallisation of PEO. For lauric acid, due to facile crystallisation and self-association, formation of ordered regular structures takes place faster and is influenced by non-reversing processes in higher proportion. (author)

  20. Crystallization and unusual rheological behavior in poly(ethylene oxide)–clay nanocomposites

    KAUST Repository

    Kelarakis, Antonios

    2011-05-01

    We report a systematic study of the crystallization and rheological behavior of poly(ethylene oxide) (PEO)-clay nanocomposites. To that end a series of nanocomposites based on PEOs of different molecular weight (103 < MW < 105 g/mol) and clay surface modifier was synthesized and characterized. Incorporation of organoclays with polar (MMT-OH) or aromatic groups (MMT-Ar) suppresses the crystallization of polymer chains in low MW PEO, but does not significantly affect the crystallization of high MW matrices. In addition, the relative complex viscosity of the nanocomposites based on low MW PEO increases significantly, but the effect is less pronounced at higher MWs. The viscosity increases in the series MMT-Alk < MMT-OH < MMT-Ar. In contrast to the neat PEO which exhibits a monotonic decrease of viscosity with temperature, all nanocomposites show an increase after a certain temperature. This is the first report of such dramatic enhancements in the viscoelasticity of nanocomposites, which are reversible, are based on a simple polymer matrix and are true in a wide temperature range. © 2011 Elsevier Ltd. All rights reserved.

  1. Complex dynamics of capillary imbibition of poly(ethylene oxide) melts in nanoporous alumina

    Science.gov (United States)

    Yao, Yang; Alexandris, Stelios; Henrich, Franziska; Auernhammer, Günter; Steinhart, Martin; Butt, Hans-Jürgen; Floudas, George

    2017-05-01

    Capillary penetration of a series of entangled poly(ethylene oxide) melts within nanopores of self-ordered alumina follows an approximate t1/2 behavior according to the Lucas-Washburn equation; t is the time. However, the dependence on the capillary diameter deviates from the predicted proportionality to d1/2; d is the pore diameter. We observed a reversal in the dynamics of capillary rise with polymer molecular weight. Chains with 50 entanglements (Mw ≤ 100 kg/mol) or less show a slower capillary rise than theoretically predicted as opposed to chains with more entanglements (Mw ≥ 500 kg/mol) that display a faster capillary rise. Although a faster capillary rise has been predicted by theory and observed experimentally, it is the first time to our knowledge that a slower capillary rise is observed for an entangled polymer melt under conditions of strong confinement (with 2Rg/d = 1). These results are discussed in the light of theoretical predictions for the existence of a critical length scale that depends on the molecular weight and separates the microscopic (d d*) regime.

  2. Reduced-mobility layers with high internal mobility in poly(ethylene oxide)-silica nanocomposites

    Science.gov (United States)

    Golitsyn, Yury; Schneider, Gerald J.; Saalwächter, Kay

    2017-05-01

    A series of poly(ethylene oxide) nanocomposites with spherical silica was studied by proton NMR spectroscopy, identifying and characterizing reduced-mobility components arising from either room-temperature lateral adsorption or possibly end-group mediated high-temperature bonding to the silica surface. The study complements earlier neutron-scattering results for some of the samples. The estimated thickness of a layer characterized by significant internal mobility resembling backbone rotation ranges from 2 nm for longer (20 k) chains adsorbed on 42 nm diameter particles to 0.5 nm and below for shorter (2 k) chains on 13 nm particles. In the latter case, even lower adsorbed amounts are found when hydroxy endgroups are replaced by methyl endgroups. Both heating and water addition do not lead to significant changes of the observables, in contrast to other systems such as acrylate polymers adsorbed to silica, where temperature- and solvent-induced softening associated with a glass transition temperature gradient was evidenced. We highlight the actual agreement and complementarity of NMR and neutron scattering results, with the earlier ambiguities mainly arising from different sensitivities to the component fractions and the details of their mobility.

  3. Electrospun Chitosan/Polyethylene Oxide Nanofibrous Scaffolds with Potential Antibacterial Wound Dressing Applications

    Directory of Open Access Journals (Sweden)

    Tony T. Yuan

    2016-01-01

    Full Text Available Electrospinning is a simple and versatile technique for the fabrication of nonwoven fibrous materials for biomedical applications. In the present study, chitosan (CS and polyethylene oxide (PEO nanofibrous scaffolds were successfully prepared using three different CS/PEO mass ratios and then evaluated for their physical, chemical, and biological characteristics. Scaffold morphologies were observed by scanning electron microscopy, which showed decreasing fiber diameters with increasing CS content. Higher CS concentrations also correlated with increased tensile strength and decreased elasticity of the scaffold. Degradation studies demonstrated that PEO was solubilized from the scaffold within the first six hours, followed by CS. This profile was unaffected by changes in the CS/PEO ratio or the pH of the media. Only the 2 : 1 CS/PEO scaffold demonstrated superior inhibition of both growth and attachment of Staphylococcus aureus. Finally, all scaffolds exhibited little impact on the proliferation of murine fibroblast monolayers. These data demonstrate that the 2 : 1 CS/PEO scaffold is a promising candidate for wound dressing applications due to its excellent antibacterial characteristics and biocompatibility.

  4. AC and DC electrospinning of hydroxypropylmethylcellulose with polyethylene oxides as secondary polymer for improved drug dissolution.

    Science.gov (United States)

    Balogh, Attila; Farkas, Balázs; Verreck, Geert; Mensch, Jürgen; Borbás, Enikő; Nagy, Brigitta; Marosi, György; Nagy, Zsombor Kristóf

    2016-05-30

    Alternating current electrospinning (ACES) capable to reach multiple times higher specific productivities than widely used direct current electrospinning (DCES) was investigated and compared with DCES to prepare drug-loaded formulations based on one of the most widespread polymeric matrix used for commercialized pharmaceutical solid dispersions, hydroxypropylmethylcellulose 2910 (HPMC). In order to improve the insufficient spinnability of HPMC (both with ACES and DCES) polyethylene oxide (PEO) as secondary polymer with intense ACES activity was introduced into the electrospinning solution. Different grades of this polymer used at as low concentrations in the fibers as 0.1% or less enabled the production of high quality HPMC-based fibrous mats without altering its physicochemical properties remarkably. Increasing concentrations of higher molecular weight PEOs led to the thickening of fibers from submicronic diameters to several microns of thickness. ACES fibers loaded with the poorly water-soluble model drug spironolactone were several times thinner than drug-loaded fibers prepared with DCES in spite of the higher feeding rates applied. The amorphous HPMC-based fibers with large surface area enhanced the dissolution of spironolactone significantly, the presence of small amounts of PEO did not affect the dissolution rate. The presented results confirm the diverse applicability of ACES, a novel technique to prepare fibrous drug delivery systems.

  5. High efficiency solid state dye sensitized solar cells with graphene-polyethylene oxide composite electrolytes.

    Science.gov (United States)

    Akhtar, M Shaheer; Kwon, Soonji; Stadler, Florian J; Yang, O Bong

    2013-06-21

    Novel and highly effective composite electrolytes were prepared by combining the two dimensional graphene (Gra) and polyethylene oxide (PEO) for the solid electrolyte of dye sensitized solar cells (DSSCs). Gra sheets were uniformly coated by the polymer layer through the ester carboxylate bonding between oxygenated species on Gra sheets and PEO. The Gra-PEO composite electrolyte showed the large scale generation of iodide ions in a redox couple. From rheological analysis, the decrease in viscosity after the addition of LiI and I2 in the Gra-PEO electrolyte might be explained by the dipolar interactions being severely disrupted by the ionic interactions of Li(+), I(-), and I3(-) ions. A composite electrolyte with 0.5 wt% Gra presented a higher ionic conductivity (3.32 mS cm(-1)) than those of PEO and other composite electrolytes at room temperature. A high overall conversion efficiency (∼5.23%) with a very high short circuit current (JSC) of 18.32 mA cm(-2), open circuit voltage (VOC) of 0.592 V and fill factor (FF) of 0.48 was achieved in DSSCs fabricated with the 0.5 wt% Gra-PEO composite electrolyte. This enhanced photovoltaic performance might be attributed to the large scale formation of iodide ions in the redox electrolyte and the relatively high ionic conductivity.

  6. Antibacterial electrospun chitosan-polyethylene oxide nanocomposite mats containing bioactive silver nanoparticles.

    Science.gov (United States)

    Kohsari, Iraj; Shariatinia, Zahra; Pourmortazavi, Seied Mahdi

    2016-04-20

    The antimicrobial chitosan-polyethylene oxide (CS-PEO) nanofibrous mats were developed by electrospinning technique for wound dressing applications. Indeed, a green route was introduced for fabrication of antibacterial mats loaded with 0.25% and 0.50% (w/w) of bioactive silver nanoparticles (Ag NPs, ∼70nm diameter) reduced by Falcaria vulgaris herbal extract. The mats were characterized by FE-SEM, EDAX, elemental mapping, FT-IR, contact angle, TGA/DSC as well as tensile strength analysis. All of the nanofibers had an average ∼200nm diameter. Interestingly, both of the CS-PEO mats containing 0.25% and 0.50% bioactive F. vulgaris-Ag NPs revealed 100% bactericidal activities against both Staphylococcus aureus and Escherichia coli bacteria. The silver release from nanofiber mats was sharply increased within first eight hours for both CS-PEO mats including 0.25% and 0.50% F. vulgaris-Ag NPs but after that the Ag nanoparticles were released very slowly (almost constant). The improved hydrophilicity, higher tensile strength and much greater silver release for CS-PEO-0.50% F. vulgaris-Ag NPs relative to those of the CS-PEO 0.25% F. vulgaris-Ag NPs suggested that the former was superior for biomedical applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Polyethylene oxide (PEO)-hyaluronic acid (HA) nanofibers with kanamycin inhibits the growth of Listeria monocytogenes.

    Science.gov (United States)

    Ahire, J J; Robertson, D D; van Reenen, A J; Dicks, L M T

    2017-02-01

    Listeria monocytogenes is well known to cause prosthetic joint infections in immunocompromised patients. In this study, polyethylene oxide (PEO) nanofibers, containing kanamycin and hyaluronic acid (HA), were prepared by electrospinning at a constant electric field of 10kV. PEO nanofibers spun with 0.2% (w/v) HA and 1% (w/v) kanamycin had a smooth, bead-free structure at 30-35% relative humidity. The average diameter of the nanofibers was 83±20nm. Attenuated total reflectance (ATR)-Fourier transform infrared (FTIR) spectroscopy indicated that kanamycin was successfully incorporated into PEO/HA matrix. The presence of kanamycin affects the thermal properties of PEO/HA nanofibers, as shown by differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA). The kanamycin-PEO-HA nanofibers (1mg; 47±3μg kanamycin) inhibited the growth of L. monocytogenes EDGe by 62%, as compared with PEO-HA nanofibers, suggesting that it may be used to coat prosthetic implants to prevent secondary infections.

  8. Characterization of Polyethylene Oxide and Sodium Alginate for Oil Contaminated-Sand Remediation

    Directory of Open Access Journals (Sweden)

    Jongwon Jung

    2017-01-01

    Full Text Available Biopolymers have been employed in many soil applications, such as oil-contaminated soil remediation, due to their environmentally friendly characteristics. This study focused on changes in the wettability and viscosity of polyethylene oxide (PEO and sodium alginate (SA, according to the variation in concentration and their impact on oil-contaminated soil remediation using biopolymer-decane displacement tests. The contact angle and interfacial tension vary with concentration by adding biopolymer to water; however both parameters yield relatively constant values within the range of 2–10 g/L for the concentration of PEO and SA. In this study, their influence on fluid invasion patterns is insignificant compared to viscosity and flow rate. Viscosity increases with the concentration of PEO and SA, within the range of 0–10 g/L, which causes the biopolymer-decane displacement ratio to increase with concentration. Biopolymer-decane displacement increases with injected fluid velocity. At low flow rates, the effect of the biopolymer concentration on the displacement ratio is prominent. However the effect decreases with an increase in flow rate. Thus both biopolymer concentration and injection velocity should be considered to achieve the economic efficiency of soil remediation. The experimental results for the distribution of soils with different grain sizes indicate that the displacement ratio increases with the uniformity of the coefficient of soils.

  9. Effect of Nanodiamonds on Structure and Durability of Polyethylene Oxide-Based Nanocomposites

    Directory of Open Access Journals (Sweden)

    Rossella Arrigo

    2016-01-01

    Full Text Available Polymer-based nanocomposites containing nanodiamonds (NDs are attractive multifunctional materials with a growing range of applications. In this work, in the frame of developing completely biocompatible systems, nanocomposites based on polyethylene oxide (PEO and different amount of NDs have been formulated through melt mixing and fully characterized. In particular, the reinforcement effect of NDs in PEO has been probed through tensile tests, and the rheological response of PEO-based nanocomposites as a function of the nanoparticles amount has been investigated and discussed. The obtained results show that the presence of well-distributed NDs strengthens the mechanical performance of the nanocomposites and brings about an increase of the PEO crystallinity, suggesting a strong adhesion between NDs and polymer matrix. Furthermore, as a result of NDs adding, alterations of the rheological behaviour of neat PEO can be noticed, as NDs are able to significantly influence the long-range dynamics of PEO chains. Besides, accelerated aging tests demonstrate that NDs show a remarkable protective ability against PEO photodegradation, due to their ability to attenuate efficiently UV radiation. The latter opens up new avenues for the use of NDs as multifunctional nanofillers for polymer-based nanocomposites with enhanced photooxidative resistance.

  10. Demicellization of Polyethylene Oxide in Water Solution under Static Magnetic Field Exposure Studied by FTIR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Emanuele Calabrò

    2013-01-01

    Full Text Available FTIR spectroscopy was used to investigate the alterations of the vibration bands in the mid-infrared region of Polyethylene oxide in aqueous solution at 25 mg/mL concentration under exposure up to 4 h to a static magnetic field at 200 mT. FTIR spectroscopic analysis of PEO solution in the range 3500–1000 cm−1 evidenced the stretching vibrations of ether band, C–H symmetric-antisymmetric and bending vibrations of methylene groups, and the C–O–C stretching band. A significant decrease in intensity of symmetric and asymmetric stretching CH2 vibration bands occurred after 2 h and 4 h of exposure, followed by a significant decrease in intensity of scissoring bending in plane CH2 vibration around 1465 cm−1. Finally, the C–O–C stretching band around 1080 cm−1 increased in intensity after 4 h of exposure. This result can be attributed to the increase of formation of the intermolecular hydrogen bonding that occurred in PEO aqueous solution after SMF exposure, due to the reorientation of PEO chain after exposure to SMF. In this scenario, the observed decrease in intensity of CH2 vibration bands can be understood as well considering that the reorientation of PEO chain under the applied SMF induces PEO demicellization.

  11. Lithium perchlorate ion pairing in a model of amorphous polyethylene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Halley, J.W.; Duan, Y. [School of Physics and Astronomy, University of Minnesota, Minneapolis, Minnesota 55455 (United States); Curtiss, L.A.; Baboul, A.G. [Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    1999-08-01

    We report a molecular dynamics study of pairing and dynamics of lithium cation and perchlorate anion in a previously reported model of amorphous polyethylene oxide. We are particularly interested in the question of whether these ions pair in the model, as previously reported experimentally. We calculate the potential of mean force between a lithium and perchlorate ion in the system for several temperatures when a pair of ions is at various separation distances in our model. We find evidence for two minima in the potential of mean force, one at lithium{endash}chlorine separations of 3.5 {Angstrom} and about 6.5 {Angstrom}. We studied the same system with five ion pairs in the system and again find two minima at the same separation distances but in this case there is evidence of entropic effects in the binding free energy of the pairs at 3.5 {Angstrom}. A study of radial distribution functions permits us to deduce information concerning the structure of the paired states. {copyright} {ital 1999 American Institute of Physics.}

  12. Effects of ionic liquids on cation dynamics in amorphous polyethylene oxide electrolytes

    Science.gov (United States)

    Chattoraj, Joyjit; Diddens, Diddo; Heuer, Andreas

    2014-01-01

    We perform extensive molecular dynamics simulations of a poly(ethylene oxide)-based polymer electrolyte material containing lithium bis(trifluoromethanesulfonyl)imide salt for a wide temperature regime above and below the experimental crystallization temperature with and without N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid (IL). The impact of the IL-concentration on the cation dynamics is studied. The increase of the cation mobility upon addition of IL is significant but temperature-independent. This can be related to distinct variations of the underlying transport properties as expressed within the previously introduced transport model of polymer electrolytes. Even for the largest IL concentration the transport model perfectly predicts the non-trivial time-dependence of the cationic mean square displacement for all temperatures. Finally, we compare our numerical and theoretical findings with the results of recent nuclear magnetic resonance experiments. In this way we can exclusively relate the strong experimentally observed dependence of the low-temperature Li-diffusivity on the IL concentration to the impact of IL on crystallization.

  13. Effects of ionic liquids on cation dynamics in amorphous polyethylene oxide electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Chattoraj, Joyjit, E-mail: jchat-01@uni-muenster.de; Diddens, Diddo; Heuer, Andreas [Institut für Physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 28/30, D-48149 Münster (Germany)

    2014-01-14

    We perform extensive molecular dynamics simulations of a poly(ethylene oxide)-based polymer electrolyte material containing lithium bis(trifluoromethanesulfonyl)imide salt for a wide temperature regime above and below the experimental crystallization temperature with and without N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid (IL). The impact of the IL-concentration on the cation dynamics is studied. The increase of the cation mobility upon addition of IL is significant but temperature-independent. This can be related to distinct variations of the underlying transport properties as expressed within the previously introduced transport model of polymer electrolytes. Even for the largest IL concentration the transport model perfectly predicts the non-trivial time-dependence of the cationic mean square displacement for all temperatures. Finally, we compare our numerical and theoretical findings with the results of recent nuclear magnetic resonance experiments. In this way we can exclusively relate the strong experimentally observed dependence of the low-temperature Li-diffusivity on the IL concentration to the impact of IL on crystallization.

  14. Nuclear magnetic relaxation study of poly(ethylene oxide)-lithium salt based electrolytes

    Science.gov (United States)

    Donoso, J. P.; Bonagamba, T. J.; Panepucci, H. C.; Oliveira, L. N.; Gorecki, W.; Berthier, C.; Armand, M.

    1993-06-01

    We have studied the low-temperature NMR line shape for three nuclei (1H, 7Li, and 19F) in poly(ethylene oxide)-lithium salts (LiClO4, LiBF4, and LiAsF6) solid polymer ionic conductors and measured their spin-lattice relaxation rates as functions of frequency and temperature. The three nuclei probe the dynamics of the polymer segments, the cations, and the anions. We find that the Li+ cations follow the segmental motion of the chain, while the anions move independently. Homonuclear interactions and heteronuclear interactions with the polymer and the anion contribute to the 7Li line shape. When the heteronuclear contributions were selectively eliminated by the decoupling method, it was found that the Li-H interaction accounts for 80%-90% of the linewidth. Additional evidence for the correlation between the cationic and the polymeric motions is provided by the remarkably similar temperature dependences of the measured relaxation rates for 7Li and 1H, which differ significantly from the dependence for 19F. The frequency dependence of the relaxation rates is poorly described by the Bloembergen, Purcell, and Pound model; a recently developed graphical procedure nevertheless shows that the motion of the protons and the anions is governed by a single time scale, while the 7Li ions are affected by an additional scale, associated with the coupling of its quadrupolar moment to the electric-field gradient.

  15. Lithium Ion Pathway within Li7 La3 Zr2 O12 -Polyethylene Oxide Composite Electrolytes.

    Science.gov (United States)

    Zheng, Jin; Tang, Mingxue; Hu, Yan-Yan

    2016-09-26

    Polymer-ceramic composite electrolytes are emerging as a promising solution to deliver high ionic conductivity, optimal mechanical properties, and good safety for developing high-performance all-solid-state rechargeable batteries. Composite electrolytes have been prepared with cubic-phase Li7 La3 Zr2 O12 (LLZO) garnet and polyethylene oxide (PEO) and employed in symmetric lithium battery cells. By combining selective isotope labeling and high-resolution solid-state Li NMR, we are able to track Li ion pathways within LLZO-PEO composite electrolytes by monitoring the replacement of (7) Li in the composite electrolyte by (6) Li from the (6) Li metal electrodes during battery cycling. We have provided the first experimental evidence to show that Li ions favor the pathway through the LLZO ceramic phase instead of the PEO-LLZO interface or PEO. This approach can be widely applied to study ion pathways in ionic conductors and to provide useful insights for developing composite materials for energy storage and harvesting. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Poly(ethylene oxide)/clay nanaocomposites: Thermal and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Ejder-Korucu, Mehtap, E-mail: mehtapejderk@gmail.com [Department of Chemistry, Faculty of Science and Literature, Kafkas University, 36000 Kars (Turkey); Gürses, Ahmet [Department of Chemistry Education, K.K. Education Faculty, Ataturk University, 25240 Erzurum (Turkey); Karaca, Semra [Department of Chemistry, Faculty of Science, Ataturk University, 25240 Erzurum (Turkey)

    2016-08-15

    Highlights: • PEO/clay nanocomposites were prepared via solution intercalation. Complete exfoliation occurs in samples of 0.5 and 2.0 CEC. • The impaired helical structure of PEO in nanocomposite structures had been verified based on the results of FTIR studies. • The crystallization temperature of PEO/OMMT nanocomposites is low compared to raw polymer. • The increase of melting temperatures indicates the increase of the stability of PEO in case of availability of clay. • The tensile strength, yield strength, % stretching of nanocomposite samples increase compared to raw polymer at all CEC rates. - Abstract: Poly(ethylene oxide) (PEO)/clay nanocomposites were prepared by a solution intercalation method using chloroform as a solvent. The nanocomposites were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR) and also investigation of some mechanical properties of the composites. Formation of nanocomposite was confirmed by XRD analysis. The increasing tendency of exfoliation degree with an increase in clay content may be attributed to easier diffusion of PEO chains to interlayer regions. An increase in PEO crystallinity in case of nanocomposite, was confirmed by an increase in the heat of melting as indicated by DSC. Improvement in tensile properties in all respect was observed for nanocomposites with clay content.

  17. Titanate nanotubes for reinforcement of a poly(ethylene oxide)/chitosan polymer matrix

    Science.gov (United States)

    Porras, R.; Bavykin, D. V.; Zekonyte, J.; Walsh, F. C.; Wood, R. J.

    2016-05-01

    Soft polyethylene oxide (PEO)/chitosan mixtures, reinforced with hard titanate nanotubes (TiNTs) by co-precipitation from aqueous solution, have been used to produce compact coatings by the ‘drop-cast’ method, using water soluble PEO polymer and stable, aqueous colloidal solutions of TiNTs. The effects of the nanotube concentration and their length on the hardness and modulus of the prepared composite have been studied using nanoindentation and nanoscratch techniques. The uniformity of TiNT dispersion within the polymer matrix has been studied using transmission electron microscopy (TEM). A remarkable increase in hardness and reduced Young’s modulus of the composites, compared to pure polymer blends, has been observed at a TiNT concentration of 25 wt %. The short (up to 30 min) ultrasound treatment of aqueous solutions containing polymers and a colloidal TiNT mixture prior to drop casting has resulted in some improvements in both hardness and reduced Young’s modulus of dry composite films, probably due to a better dispersion of ceramic nanotubes within the matrix. However, further (more than 1 h) treatment of the mixture with ultrasound resulted in a deterioration of the mechanical properties of the composite accompanied by a shortening of the nanotubes, as observed by the TEM.

  18. Poly(ethylene oxide) Functionalized Graphene Nanoribbons with Excellent Solution Processability.

    Science.gov (United States)

    Huang, Yinjuan; Mai, Yiyong; Beser, Uliana; Teyssandier, Joan; Velpula, Gangamallaiah; van Gorp, Hans; Straasø, Lasse Arnt; Hansen, Michael Ryan; Rizzo, Daniele; Casiraghi, Cinzia; Yang, Rong; Zhang, Guangyu; Wu, Dongqing; Zhang, Fan; Yan, Deyue; De Feyter, Steven; Müllen, Klaus; Feng, Xinliang

    2016-08-17

    Structurally well-defined graphene nanoribbons (GNRs) have attracted great interest as next-generation semiconductor materials. The functionalization of GNRs with polymeric side chains, which can widely broaden GNR-related studies on physiochemical properties and potential applications, has remained unexplored. Here, we demonstrate the bottom-up solution synthesis of defect-free GNRs grafted with flexible poly(ethylene oxide) (PEO) chains. The GNR backbones possess an armchair edge structure with a width of 1.0-1.7 nm and mean lengths of 15-60 nm, enabling near-infrared absorption and a low bandgap of 1.3 eV. Remarkably, the PEO grafting renders the GNRs superb dispersibility in common organic solvents, with a record concentration of ∼1 mg mL(-1) (for GNR backbone) that is much higher than that (<0.01 mg mL(-1)) of reported GNRs. Moreover, the PEO-functionalized GNRs can be readily dispersed in water, accompanying with supramolecular helical nanowire formation. Scanning probe microscopy reveals raft-like self-assembled monolayers of uniform GNRs on graphite substrates. Thin-film-based field-effect transistors (FETs) of the GNRs exhibit a high carrier mobility of ∼0.3 cm(2) V(-1) s(-1), manifesting promising application of the polymer-functionalized GNRs in electronic devices.

  19. The diffusion and conduction of lithium in poly(ethylene oxide)-based sulfonate ionomers

    Science.gov (United States)

    LaFemina, Nikki H.; Chen, Quan; Colby, Ralph H.; Mueller, Karl T.

    2016-09-01

    Pulsed field gradient nuclear magnetic resonance spectroscopy and dielectric relaxation spectroscopy have been utilized to investigate lithium dynamics within poly(ethylene oxide) (PEO)-based lithium sulfonate ionomers of varying ion content. The ion content is set by the fraction of sulfonated phthalates and the molecular weight of the PEO spacer, both of which can be varied independently. The molecular level dynamics of the ionomers are dominated by either Vogel-Fulcher-Tammann or Arrhenius behavior depending on ion content, spacer length, temperature, and degree of ionic aggregation. In these ionomers the main determinants of the self-diffusion of lithium and the observed conductivities are the ion content and ionic states of the lithium ion, which are profoundly affected by the interactions of the lithium ions with the ether oxygens of the polymer. Since many lithium ions move by segmental polymer motion in the ion pair state, their diffusion is significantly larger than that estimated from conductivity using the Nernst-Einstein equation.

  20. Self-organization of poly(ethylene oxide) on the surface of aqueous salt solutions.

    Science.gov (United States)

    Fuchs, Christian; Hussain, Hazrat; Amado, Elkin; Busse, Karsten; Kressler, Joerg

    2015-01-01

    It is demonstrated that stable Langmuir films of poly(ethylene oxide) (PEO) can be formed up to surface pressures of 30 mN m(-1) when potassium carbonate K2CO3 is added to the aqueous subphase. Generally, PEO homopolymer cannot stay on the water surface at a surface pressure ≥10 mN m(-1) due to its high water solubility. To prepare stable monolayer films, PEO can be modified with hydrophobic moieties. However, by exploiting the salting out effect by adding certain salts (K2CO3 or MgSO4) into the aqueous subphase, not only very stable films but also unusual self-organization can be achieved by the PEO homopolymer on the surface of the aqueous solution. Thus, a series of OH-terminated PEOs is found to form a stable monolayer at K2CO3 concentrations of 2 M and above in the aqueous subphase, and the stability of the film increases with an increase in K2CO3 concentration. Hysteresis experiments are also carried out. During the phase transition induced by progressive compression, self-organization into well-defined domains with sizes in the micrometer range are observed, and with further compression and holding of the film for 30 min and above the microdomains transform into a crystalline morphology as visualized by Brewster angle microscopy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. AFM-tip-induced crystallization of poly(ethylene oxide)melt droplets

    Institute of Scientific and Technical Information of China (English)

    ZHU Dunshen; SHOU Xingxian; LIU Yixin; CHEN Erqiang; Stephen Zhengdi Cheng

    2007-01-01

    The AFM-tip-induced crystallization of poly(ethylene oxide) (PEO) melt droplets was studied.The melt droplets with a height of 50-100 nm and a lateral size of 2-3 pm were obtained by melting the PEO ultra-thin films on a mica surface.For the PEO samples with average molecular weights (Mn) ranging from 1.0×103 g/mol to 1.0×104 g/mol,the lateral perturbation from the AFM tip in the hard-tapping or nanoscratch modes could not induce the growth of the flaton lamellae.In contrast,under AFM nanoindentation mode,the tip-induced crystallization occurred when a sufficiently high vertical tip force was applied to the melt droplets of PEO with Mn≥1.0×104 g/mol. Moreover,the experimental results indicated that the AFM-tip-induced crystallization of PEO in the nanoindentation process had molecular weight dependence.

  2. FTIR assessment of poly(ethylene oxide) irradiated in solid state, melt and aqeuous solution

    Science.gov (United States)

    Pucić, Irina; Jurkin, Tanja

    2012-09-01

    FTIR spectroscopy was used to study poly(ethylene oxide), PEO, irradiated in solid and molten aggregate states and as aqueous solutions of various concentrations. The changes in shape and width of -C-O-C- complex absorption intensities at around 1112 cm-1 were the most prominent. On irradiation of solid samples in contact with air shrinking of -C-O-C- complex and increase in its absorption intensities indicated predominant degradation. Crosslinking prevailed on irradiation of molten PEO and of its aqueous solutions in nitrogen atmosphere and manifested itself as widening of -C-O-C- absorption and decrease of corresponding intensities. Partial or complete merging of CH2 wagging vibrations at 1342 cm-1 and 1360 cm-1 that are characteristic of crystalline PEO into a single absorption at around 1350 cm-1 indicated amorphization what was observed for samples that had reduced degree of crystallinity determined by differential scanning calorimetry. DSC could not discriminate between degradation and crosslinking while the changes in width and shape of -C-O-C- complex were independent of the changes in crystallinity. Comparison of FTIR spectra of the same PEO samples obtained as thin film and as KBr pellets revealed that pellet preparation results in a number of spectral artefacts.

  3. Solid-phase photocatalytic degradation of polyethylene film with manganese oxide OMS-2

    Science.gov (United States)

    Liu, Guanglong; Liao, Shuijiao; Zhu, Duanwei; Cui, Jingzhen; Zhou, Wenbing

    2011-01-01

    Solid-phase photocatalytic degradation of polyethylene (PE) film with cryptomelane-type manganese oxide (OMS-2) as photocatalyst was investigated in the ambient air under ultraviolet and visible light irradiation. The properties of the composite films were compared with those of the pure PE film through performing weight loss monitoring, IR spectroscopy, scanning electron microscopic (SEM) and X-ray photoelectron spectroscopy (XPS). The photoinduced degradation of PE-OMS-2 composite films was higher than that of the pure films, while there has been little change under the visible light irradiation. The weight loss of PE-OMS-2 (1.0 wt%) composite films steadily decreased and reached 16.5% in 288 h under UV light irradiation. Through SEM observation there were some cavities on the surface of composite films, but few change except some surface chalking phenomenon occurred in pure PE film. The degradation rate with ultraviolet irradiation is controllable by adjusting the content of OMS-2 particles in PE plastic. Finally, the mechanism of photocatalytic degradation of the composite films was briefly discussed.

  4. Design and development of polyethylene oxide based matrix tablets for verapamil hydrochloride

    Directory of Open Access Journals (Sweden)

    S Vidyadhara

    2013-01-01

    Full Text Available In the present investigation an attempt has been made to increase therapeutic efficacy, reduced frequency of administration and improved patient compliance by developing controlled release matrix tablets of verapamil hydrochloride. Verapamil hydrochloride was formulated as oral controlled release matrix tablets by using the polyethylene oxides (Polyox WSR 303. The aim of this study was to investigate the influence of polymer level and type of fillers namely lactose (soluble filler, swellable filler (starch 1500, microcrystalline cellulose and dibasic calcium phosphate (insoluble fillers on the release rate and mechanism of release for verapamil hydrochloride from matrix tablets prepared by direct compression process. Higher polymeric content in the matrix decreased the release rate of drug. On the other hand, replacement of lactose with anhydrous dibasic calcium phosphate and microcrystalline cellulose has significantly retarded the release rate of verapamil hydrochloride. Biopharmaceutical evaluation of satisfactory formulations were also carried out on New Zealand rabbits and parameters such as maximum plasma concentration, time to reach peak plasma concentration, area under the plasma concentration time curve (0-t and area under first moment curve (0-t were determined. In vivo pharmacokinetic study proves that the verapamil hydrochloride from matrix tablets showed prolonged release and were be able to sustain the therapeutic effect up to 24 h.

  5. Amperometric Biosensor Based on Zirconium Oxide/Polyethylene Glycol/Tyrosinase Composite Film for the Detection of Phenolic Compounds.

    Science.gov (United States)

    Ahmad, Nor Monica; Abdullah, Jaafar; Yusof, Nor Azah; Ab Rashid, Ahmad Hazri; Abd Rahman, Samsulida; Hasan, Md Rakibul

    2016-06-29

    A phenolic biosensor based on a zirconium oxide/polyethylene glycol/tyrosinase composite film for the detection of phenolic compounds has been explored. The formation of the composite film was expected via electrostatic interaction between hexacetyltrimethylammonium bromide (CTAB), polyethylene glycol (PEG), and zirconium oxide nanoparticles casted on screen printed carbon electrode (SPCE). Herein, the electrode was treated by casting hexacetyltrimethylammonium bromide on SPCE to promote a positively charged surface. Later, zirconium oxide was mixed with polyethylene glycol and the mixture was dropped cast onto the positively charged SPCE/CTAB. Tyrosinase was further immobilized onto the modified SPCE. Characterization of the prepared nanocomposite film and the modified SPCE surface was investigated by scanning electron microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), and Cyclic voltamogram (CV). The developed biosensor exhibits rapid response for less than 10 s. Two linear calibration curves towards phenol in the concentrations ranges of 0.075-10 µM and 10-55 µM with the detection limit of 0.034 µM were obtained. The biosensor shows high sensitivity and good storage stability for at least 30 days.

  6. Relationship between hydroperoxide concentration and average molar mass in thermo-oxidized polyethylene

    Science.gov (United States)

    Da Cruz, Manuela; Van Schoors, Laetitia; Colin, Xavier; Benzarti, Karim

    2014-05-01

    The aim of this research project is to investigate the oxidation mechanism of high density polyethylene (HDPE) used in outdoor applications, in order to establish in a near future, a non-empirical kinetic model for lifetime prediction. The present paper focuses on the changes in the hydroperoxide (POOH) concentration induced by thermo-oxidative ageing, and on their relationship with the evolution of the weight average molar mass (Mw) due both to chain scission and crosslinking processes. Thin HDPE films were aged at 110 and 140°C in air under atmospheric pressure. In a first part, changes in the POOH concentration versus ageing time were assessed by three different analytical methods previously reported in the literature: modulated differential scattering calorimetry (MDSC), Fourier transform Infra-Red spectrometry after chemical derivatization treatment with gaseous sulfur dioxide (SO2-FTIR), and iodometry. A comparison of experimental results revealed that these three methods provide very similar quantitative data on POOH accumulation, whereas iodometry tends to strongly underestimate the subsequent stage of POOH decomposition. It was thus suspected that iodometry does not only titrate POOH, but also other chemical species (presumably double bonds) formed when POOH decompose. Therefore, only MDSC and SO2-FTIR were considered as relevant methods for POOH titration. In a second part, changes in Mw versus ageing time were monitored by size exclusion chromatography (SEC). A sharp drop of Mw was first observed at the beginning of exposure, which was assigned to an intensive chain scission process. Then, in a second stage, a stabilization or even a substantial re-increase in Mw was observed, suggesting a competition between chain scission and crosslinking processes. As this second stage starts at the same time as POOH decomposition, it was concluded that there is a strong correlation between both phenomena, occurring respectively at the macromolecular and molecular

  7. Polyethylene Glycol-Mediated Synthesis of Cubic Iron Oxide Nanoparticles with High Heating Power

    Science.gov (United States)

    Iacovita, Cristian; Stiufiuc, Rares; Radu, Teodora; Florea, Adrian; Stiufiuc, Gabriela; Dutu, Alina; Mican, Sever; Tetean, Romulus; Lucaciu, Constantin M.

    2015-10-01

    Iron oxide magnetic nanoparticles (IOMNPs) have been successfully synthesized by means of solvothermal reduction method employing polyethylene glycol (PEG200) as a solvent. The as-synthesized IOMNPs are poly-dispersed, highly crystalline, and exhibit a cubic shape. The size of IOMNPs is strongly dependent on the reaction time and the ration between the amount of magnetic precursor and PEG200 used in the synthesis method. At low magnetic precursor/PEG200 ratio, the cubic IOMNPs coexist with polyhedral IOMNPs. The structure and morphology of the IOMNPs were thoroughly investigated by using a wide range of techniques: TEM, XRD, XPS, FTIR, and RAMAN. XPS analysis showed that the IOMNPs comprise a crystalline magnetite core bearing on the outer surface functional groups from PEG200 and acetate. The presence of physisorbed PEG200 on the IOMNP surface is faintly detected through FT-IR spectroscopy. The surface of IOMNPs undergoes oxidation into maghemite as proven by RAMAN spectroscopy and the occurrence of satellite peaks in the Fe2p XP spectra. The magnetic studies performed on powder show that the blocking temperature (TB) of IOMNPs is around 300 K displaying a coercive field in between 160 and 170 Oe. Below the TB, the field-cooled (FC) curves turn concave and describe a plateau indicating that strong magnetic dipole-dipole interactions are manifested in between IOMNPs. The specific absorption rate (SAR) values increase with decreasing nanoparticle concentrations for the IOMNPs dispersed in water. The SAR dependence on the applied magnetic field, studied up to magnetic field amplitude of 60 kA/m, presents a sigmoid shape with saturation values up to 1700 W/g. By dispersing the IOMNPs in PEG600 (liquid) and PEG1000 (solid), it was found that the SAR values decrease by 50 or 75 %, indicating that the Brownian friction within the solvent was the main contributor to the heating power of IOMNPs.

  8. Coarse-graining poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers using the MARTINI force field.

    Science.gov (United States)

    Nawaz, Selina; Carbone, Paola

    2014-02-13

    The MARTINI coarse-grain (CG) force field is extended for a class of triblock block copolymers known as Pluronics. Existing MARTINI bead types are used to model the non-bonded part of the potential while single chain properties for both homopolymers, poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO), are used to develop the bonded interactions. The new set of force field parameters reproduces structural and dynamical properties of high molecular weight homo- and copolymers. The CG model is moderately transferable in solvents of different polarity and concentration; however, the PEO homopolymer model presents a reduced thermodynamic transferability especially in water probably due to the lack of hydrogen bonds with the solvent. Our simulations of a monolayer of Pluronic L44 show polymer-brush-like characteristics for the PEO segments which protrude into the aqueous phase. Other membrane properties not easily accessible using experimental techniques such as its membrane thickness are also calculated.

  9. Surface-gradient cross-linked polyethylene acetabular cups: oxidation resistance and wear against smooth and rough femoral balls.

    Science.gov (United States)

    Shen, Fu-Wen; McKellop, Harry

    2005-01-01

    Two methods were developed and evaluated for cross-linking the bearing surface of a polyethylene acetabular cup to a limited depth, in order to improve its resistance to wear without degrading the mechanical properties of the bulk of the component. In the first method, low-energy electron beams were used to cross-link only the bearing surface of the cups to a maximum depth of about 2 mm. The cups then were annealed at 100 degrees C in vacuum for 3 or 6 days to reduce the residual free radicals, and the resultant resistance to oxidation was compared by artificially aging the cups at 80 degrees C in air. Chemically cross-linked surface layers were produced by coating the bearing surfaces of the cups with a thin layer of polyethylene powder mixed with 1% weight peroxide, and compressing them at 6.9 MPa (1000 psi) and 170 degrees C. This resulted in a cross-linked surface layer that extended about 3 mm deep, with a gradual transition to conventional (noncross-linked) polyethylene in the bulk of the implant. In hip simulator wear tests with highly polished (implant quality) femoral balls, both types of surface cross-linking were found to improve markedly the wear resistance of the acetabular cups. In tests with roughened femoral balls, the wear rates were much higher and were comparable to those obtained with similarly roughened balls against noncross-linked polyethylene cups in a previous study, indicating that the full benefit of cross-linking may not be realized under conditions of severe third-body abrasion. Nevertheless, these results show a promising approach for optimizing the wear resistance and the bulk mechanical properties of polyethylene components in total joint arthroplasty.

  10. Mesoscopic simulation of a micellar poly(N-isopropyl acrylamide)-b-(polyethylene oxide) copolymer system

    Science.gov (United States)

    Bautista-Reyes, Rubén; Soto-Figueroa, César; Vicente, Luis

    2016-05-01

    In this article we studied the micellar formation of poly(N-isopropyl acrylamide)-b-polyethylene oxide (PNIPAM-b-PEO) copolymers in an aqueous system. From molecular simulations the dependence on temperature of the Flory-Huggins interaction parameter χ for PNIPAM and PEO in water is obtained and compared with available experimental results and values from other theoretical calculations. By means of dissipative particle dynamics (DPD) we then simulated the coil-globule transition for PNIPAM chains in water with a transition temperature of around 305 K. The simulations for PNIPAM-b-PEO copolymers showed that at room temperature the chains are miscible in an aqueous phase but with a temperature increase the system turns into micelles at T  =  305 K. The change in micelle anisotropy due to a different ratio PNIPAM/PEO of chains is also analyzed. What is observed is that for large PEO the large number of dissolved PEO chains gives a large corona size and the micelle is not spherical but obloide and as the number of PNIPAM is increased the micelle acquires a spherical shape. As an important application we considered the system micelle-water/anionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate [BMIM]+[PF6]-). By increasing the temperature of the system from 306 K it is shown that at T  =  345 K there is a transfer of the micelle from water to the ionic liquid phase and this was due to the change in the relative affinity of PEO to water and ionic liquid expressed by the change in χ. All the simulation outcomes are qualitatively consistent with experimental results and thus to our knowledge we give the first set of χ values for the interaction between PNIPAM and water in a wide range of temperature values.

  11. Activity retention after nisin entrapment in a polyethylene oxide brush layer.

    Science.gov (United States)

    Auxier, Julie A; Schilke, Karl F; McGuire, Joseph

    2014-09-01

    The cationic, amphiphilic peptide nisin is an effective inhibitor of gram-positive bacteria whose mode of action does not encourage pathogenic resistance, and its proper incorporation into food packaging could enhance food stability, safety, and quality in a number of circumstances. Sufficiently small peptides have been shown to integrate into otherwise nonfouling polyethylene oxide (PEO) brush layers in accordance with their amphiphilicity and ordered structure, including nisin, and we have recently shown that nisin entrapment within a PEO layer does not compromise the nonfouling character of that layer. In this work we test the hypothesis that surface-bound, pendant PEO chains will inhibit displacement of entrapped nisin by competing proteins and, in this way, prolong retention of nisin activity at the interface. For this purpose, the antimicrobial activity of nisinloaded, PEO-coated surfaces was evaluated against the gram-positive indicator strain, Pediococcus pentosaceous. The retained antimicrobial activity of nisin layers was evaluated on uncoated and PEO-coated surfaces after incubation in the presence of bovine serum albumin for contact periods up to 1 week. Nisin-loaded, uncoated and PEO-coated samples were withdrawn at selected times and were incubated on plates inoculated with P. pentosaceous to quantify nisin activity by determination of kill zone radii. Our results indicate that nisin activity is retained at a higher level for a longer period of time after entrapment within PEO than after direct adsorption in the absence of PEO, owing to inhibition of nisin exchange with dissolved protein afforded by the pendant PEO chains.

  12. MOLECULAR WEIGHT DEPENDENCE OF CRYSTAL PATTERN TRANSITIONS OF POLY(ETHYLENE OXIDE)

    Institute of Scientific and Technical Information of China (English)

    Guo-liang Zhang; Liu-xin Jin; Ping Zheng; Wei Wang; Xiao-jing Wen

    2013-01-01

    Crystal patterns in ultrathin films of six poly(ethylene oxide) fractions with molecular weights from 25000 to 932000 g/mol were characterized within crystallization temperature range from 20 ℃ to 60 ℃.Labyrinthine,dendritic and faceted crystal patterns were observed in different temperature ranges,and then labyrinthine-to-dendritic and dendritic-tofaceted transition temperatures TL-D and TD-F were quantitatively identified.Their molecular weight dependences are TL-D(Mw) =TL-D(∞)-KL-D/Mw,where TL-D(∞) =38.2 ℃ and KL-D =253000 ℃·g/mol and TD-F(Mw) =TD-F(∞)-KD-F/Mw,where TD-F(∞) =54.7 ℃ and KD-F =27000 ℃·g/mol.Quasi two-dimensional blob models were proposed to provide empirical explanations of the molecular weight dependences.The labyrinthine-to-dendritic transition is attributed to a molecular diffusion process change from a local-diffusion to diffusion-limited-aggregation (DLA) and a polymer chain with Mw ≈ 253000 g/mol within a blob can join crystals independently.The dendritic-to-faceted transition is attributed to a turnover of the pattern formation mechanism from DLA to crystallization control,and a polymer chain with a Mw ≈ 27000g/mol as an independent blob crosses to a depletion zone to join crystals.These molecular weight dependences reveal a macromolecular effect on the crystal pattern formation and selection of crystalline polymers.

  13. Polymer chain organization in tensile-stretched poly(ethylene oxide)-based polymer electrolytes

    Science.gov (United States)

    Burba, Christopher M.; Woods, Lauren; Millar, Sarah Y.; Pallie, Jonathan

    2011-01-01

    Polymer chain orientation in tensile-stretched poly(ethylene oxide)-lithium trifluoromethanesulfonate polymer electrolytes are investigated with polarized infrared spectroscopy as a function of the degree of strain and salt composition (ether oxygen atom to lithium ion ratios of 20:1, 15:1, and 10:1). The 1359 and 1352 cm-1 bands are used to probe the crystalline PEO and P(EO)3LiCF3SO3 domains, respectively, allowing a direct comparison of chain orientation for the two phases. Two-dimensional correlation FT-IR spectroscopy indicates that the two crystalline domains align at the same rate as the polymer electrolytes are stretched. Quantitative measurements of polymer chain orientation obtained through dichroic infrared spectroscopy show that chain orientation predominantly occurs between strain values of 150% and 250%, regardless of salt composition investigated. There are few changes in chain orientation for either phase when the films are further elongated to a strain of 300%; however, the PEO domains are slightly more oriented at the high strain values. The spectroscopic data are consistent with stretching-induced melt-recrystallization of the unoriented crystalline domains in the solution-cast polymer films. Stretching the films pulls polymer chains from the crystalline domains, which subsequently recrystallize with the polymer helices parallel to the stretch direction. If lithium ion conduction in crystalline polymer electrolytes is viewed as consisting of two major components (facile intra-chain lithium ion conduction and slow helix-to-helix inter-grain hopping), then alignment of the polymer helices will affect the ion conduction pathways for these materials by reducing the number of inter-grain hops required to migrate through the polymer electrolyte. PMID:22184475

  14. Polymer chain organization in tensile-stretched poly(ethylene oxide)-based polymer electrolytes.

    Science.gov (United States)

    Burba, Christopher M; Woods, Lauren; Millar, Sarah Y; Pallie, Jonathan

    2011-12-15

    Polymer chain orientation in tensile-stretched poly(ethylene oxide)-lithium trifluoromethanesulfonate polymer electrolytes are investigated with polarized infrared spectroscopy as a function of the degree of strain and salt composition (ether oxygen atom to lithium ion ratios of 20:1, 15:1, and 10:1). The 1359 and 1352 cm(-1) bands are used to probe the crystalline PEO and P(EO)(3)LiCF(3)SO(3) domains, respectively, allowing a direct comparison of chain orientation for the two phases. Two-dimensional correlation FT-IR spectroscopy indicates that the two crystalline domains align at the same rate as the polymer electrolytes are stretched. Quantitative measurements of polymer chain orientation obtained through dichroic infrared spectroscopy show that chain orientation predominantly occurs between strain values of 150% and 250%, regardless of salt composition investigated. There are few changes in chain orientation for either phase when the films are further elongated to a strain of 300%; however, the PEO domains are slightly more oriented at the high strain values. The spectroscopic data are consistent with stretching-induced melt-recrystallization of the unoriented crystalline domains in the solution-cast polymer films. Stretching the films pulls polymer chains from the crystalline domains, which subsequently recrystallize with the polymer helices parallel to the stretch direction. If lithium ion conduction in crystalline polymer electrolytes is viewed as consisting of two major components (facile intra-chain lithium ion conduction and slow helix-to-helix inter-grain hopping), then alignment of the polymer helices will affect the ion conduction pathways for these materials by reducing the number of inter-grain hops required to migrate through the polymer electrolyte.

  15. Nonfouling poly(ethylene oxide) layers end-tethered to polydopamine.

    Science.gov (United States)

    Pop-Georgievski, Ognen; Verreault, Dominique; Diesner, Mark-Oliver; Proks, Vladimír; Heissler, Stefan; Rypáček, František; Koelsch, Patrick

    2012-10-09

    Nonfouling surfaces capable of reducing protein adsorption are highly desirable in a wide range of applications. Coating of surfaces with poly(ethylene oxide) (PEO), a water-soluble, nontoxic, and nonimmunogenic polymer, is most frequently used to reduce nonspecific protein adsorption. Here we show how to prepare dense PEO brushes on virtually any substrate by tethering PEO to polydopamine (PDA)-modified surfaces. The chain lengths of hetero-bifunctional PEOs were varied in the range of 45-500 oxyethylene units (M(n) = 2000-20,000). End-tethering of PEO chains was performed through amine and thiol headgroups from reactive polymer melts to minimize excluded volume effects. Surface plasmon resonance (SPR) was applied to investigate the adsorption of model protein solutions and complex biologic medium (human blood plasma) to the densely packed PEO brushes. The level of protein adsorption of human serum albumin and fibrinogen solutions was below the detection limit of the SPR measurements for all PEO chains end-tethered to PDA, thus exceeding the protein resistance of PEO layers tethered directly on gold. It was found that the surface resistance to adsorption of lysozyme and human blood plasma increased with increasing length and brush character of the PEO chains end-tethered to PDA with a similar or better resistance in comparison to PEO layers on gold. Furthermore, the chain density, thickness, swelling, and conformation of PEO layers were determined using spectroscopic ellipsometry (SE), dynamic water contact angle (DCA) measurements, infrared reflection-absorption spectroscopy (IRRAS), and vibrational sum-frequency-generation (VSFG) spectroscopy, the latter in air and water.

  16. Sustained release from hot-melt extruded matrices based on ethylene vinyl acetate and polyethylene oxide.

    Science.gov (United States)

    Almeida, A; Brabant, L; Siepmann, F; De Beer, T; Bouquet, W; Van Hoorebeke, L; Siepmann, J; Remon, J P; Vervaet, C

    2012-11-01

    The aim of the present study was to evaluate the importance of matrix flexibility of hot-melt extruded (HME) ethylene vinyl acetate (EVA) matrices (with vinyl acetate (VA) contents of 9%, 15%, 28% and 40%), through the addition of hydrophilic polymers with distinct swelling capacity. Polyethylene oxide (PEO 100K, 1M and 7M) was used as swelling agent and metoprolol tartrate (MPT) as model drug. The processability via HME and drug release profiles of EVA/MPT/PEO formulations were assessed. Solid state characteristics, porosity and polymer miscibility of EVA/PEO matrices were evaluated by means of DSC, X-ray tomography and Raman spectroscopy. The processability via HME varied according to the VA content: EVA 40 and 28 were extruded at 90°C, whereas higher viscosity EVA grades (EVA 15 and 9) required a minimum extrusion temperature of 110°C to obtain high-quality extrudates. Drug release from EVA matrices depended on the VA content, PEO molecular weight and PEO content, matrix porosity as well as pore size distribution. Interestingly, the interplay of PEO leaching, matrix swelling, water influx and changes in matrix porosity influenced drug release: EVA 40- and 28-based matrices extruded with PEO of higher MW accelerated drug release, whereas for EVA 15- and 9-based matrices, drug release slowed down. These differences were related to the distinct polymer flexibility imposed by the VA content (lower VA content presents higher crystallinity and less free movement of the amorphous segments resulting in a higher rigidity). In all cases, diffusional mass transport seems to play a major role, as demonstrated by mathematical modeling using an analytical solution of Fick's second law. The bioavailability of EVA 40 and 28 matrices in dogs was not significantly different, independent of PEO 7M concentration.

  17. Crystallization behaviour of poly(ethylene oxide) under confinement in the electrospun nanofibers of polystyrene/poly(ethylene oxide) blends.

    Science.gov (United States)

    Samanta, Pratick; V, Thangapandian; Singh, Sajan; Srivastava, Rajiv; Nandan, Bhanu; Liu, Chien-Liang; Chen, Hsin-Lung

    2016-06-21

    We have studied the confined crystallization behaviour of poly(ethylene oxide) (PEO) in the electrospun nanofibers of the phase-separated blends of polystyrene (PS) and PEO, where PS was present as the major component. The size and shape of PEO domains in the nanofibers were considerably different from those in the cast films, presumably because of the nano-dimensions of the nanofibers and the extensional forces experienced by the polymer solution during electrospinning. The phase-separated morphology in turn influenced the crystallization behaviour of PEO in the blend nanofibers. At a PEO weight fraction of ≥0.3, crystallization occurred through a heterogeneous nucleation mechanism similar to that in cast blend films. However, as the PEO weight fraction in the blend nanofibers was reduced from 0.3 to 0.2, an abrupt transformation of the nucleation mechanism from the heterogeneous to predominantly homogenous type was observed. The change in the nucleation mechanism implied a drastic reduction of the spatial continuity of PEO domains in the nanofibers, which was not encountered in the cast film. The melting temperature and crystallinity of the PEO crystallites developed in the nanofibers were also significantly lower than those in the corresponding cast films. The phenomena observed were reconciled by the morphological observation, which revealed that the phase separation under the radial constraint of the nanofibers led to the formation of small-sized fibrillar PEO domains with limited spatial connectivity. The thermal treatment of the PS/PEO blend nanofibers above the glass transition temperature of PS induced an even stronger confinement effect on PEO crystallization.

  18. EFFECTS OF ORGANIC COLORANTS ON PHOTO-INITIATED CROSSLINKING AND PHOTO-OXIDATION DEGRADATION OF POLYETHYLENE AND RELATED MECHANISM

    Institute of Scientific and Technical Information of China (English)

    Guo-bing Zhang; Qiang-hua Wu; Bao-jun Qu

    2008-01-01

    The effects of three organic colorants on photo-initiated crosslinking and photo-oxidation degradation of polyethylene (PE) samples irradiated by microwave excited (MWE) UV lamp in the melt and the related mechanism have been studied by gel content and thermal extension rate determinations, X-ray photoelectron spectroscopy (XPS), mechanical property tests, UV spectroscopy, and light microscope. The data from the gel content and thermal extension rate determinations of photo-crosslinked polyethylene (XLPE) samples show that the three colorants can decrease the efficiency of photo-initiated crosslinking of polyethylene to some different degree, in which the effect of red colorant is the largest among the three colorants. The colorized samples of 1 mm thickness are easily to be crosslinked to a satisfactory gel content of about 70% by the MWE lamp and optimized reaction conditions, such as the concentration of colorant, irradiation time,and so on. The XPS results give the evidence that the colorants can accelerate the surface photo-oxidation during the photo-crosslinking of polyethylene. The photo-oxidation products such as -CH2-O-and-C(C=O)-groups on the surface of XLPE samples with the colorants apparently increase with increasing the irradiation time. The data from the mechanical tests show that the colorants reduce the tensile strength and improve the elongation at break of XLPE samples. All the above results show that the effects of the three colorants on photo-initiated crosslinking and photo-oxidative degradation decrease with the order of red > blue > green colorants. The light microscope photos show that the colorant can disperse well in PE resin. The mechanism of the colorant effects can be elucidated by comparison of the UV absorption spectra of photo-initiator and colorants. This is because the colorants absorb the same UV wavelength regions as photo-initiator, and thus decrease the photo-crosslinking efficiency of photo-initiator and accelerate the

  19. Revealing the Cytotoxicity of Residues of Phosphazene Catalysts Used for the Synthesis of Poly(ethylene oxide).

    Science.gov (United States)

    Xia, Yening; Shen, Jizhou; Alamri, Haleema; Hadjichristidis, Nikos; Zhao, Junpeng; Wang, Yucai; Zhang, Guangzhao

    2017-09-01

    We herein report a case study on the toxicity of residual catalyst in metal-free polymer. Eight-arm star-like poly(ethylene oxide)s were successfully synthesized via phosphazene-catalyzed ring-opening polymerization of ethylene oxide using sucrose as an octahydroxy initiator. The products were subjected to MTT assay using human cancer cell lines (MDA-MB-231 and A2780). Comparison between the crude and purified products clearly revealed that the residual phosphazenium salts were considerably cytotoxic, regardless of the anionic species, and that the cytotoxicity of more bulky t-BuP4 salt was higher than that of t-BuP2 salt. Such results have therefore put forward the necessity for removal of the catalyst residues from PEO-based polymers synthesized through phosphazene catalysis for biorelated applications and for the development of less or nontoxic organocatalysts for such polymers.

  20. 12-crown-4 ether-assisted enhancement of ionic conductivity and interfacial kinetics in polyethylene oxide electrolytes

    Science.gov (United States)

    Nagasubramanian, G.; Di Stefano, S.

    1990-01-01

    The electrical and electrochemical properties of thin films of polyethylene oxide electrolytes with and without 12-crown-4 ether (12Cr4) are studied as a function of temperature and in the frequency regime from 100 kHz to 0.1 Hz. These measurements were made on electrolytes containing LiCF3SO3, LiBF4, or LiClO4 salts. At a given temperature, the bulk conductivity for a particular salt depends on the 12Cr4 concentration, reaching a maximum for a ratio of 12Cr4 to Li of 0.003.

  1. Polarizable continuum model study on the solvent effect of polymer matrix in poly(ethylene oxide)-based solid electrolyte.

    Science.gov (United States)

    Eilmes, Andrzej; Kubisiak, Piotr

    2008-09-18

    The Polarizable Continuum Model has been used to study the effect of polymer matrix on Li (+) and Mg (2+) complexation in poly(ethylene oxide)-based solid electrolyte. Structures of complexes, stabilization energies, and vibrational frequencies are compared with corresponding vacuum values. The solvent effect of the polymer decreases with increasing cation coordination number. Optimized complex geometries do not differ significantly compared to vacuum calculations. Calculated shifts in vibrational frequencies depend on the complex structure; for hexacoordinated ion most frequencies are slightly red-shifted. The most important effect is the decrease of differences between relative stabilities of different structures in the solvent.

  2. Dense passivating poly(ethylene glycol) films on indium tin oxide substrates.

    Science.gov (United States)

    Schlapak, Robert; Armitage, David; Saucedo-Zeni, Nadia; Hohage, Michael; Howorka, Stefan

    2007-09-25

    We describe the formation and characterization of surface-passivating poly(ethylene glycol) (PEG) films on indium tin oxide (ITO) glass substrates. PEG chains with a molecular weight of 2000 and 5000 D were covalently attached to the substrates in a systematic approach using different coupling schemes. The coupling strategies included the direct grafting with PEG-silane, PEG-methacrylate, and PEG-bis(amine), as well as the two-step functionalization with aldehyde-bearing silane films and subsequent coupling with PEG-bis(amine). Elemental analysis by X-ray photoelectron spectroscopy (XPS) confirmed the successful surface modification, and XPS and ellipsometry provided values for film thicknesses. XPS and ellipsometry thickness values were almost identical for PEG-silane films but differed by up to 400% for the other PEG layers, suggesting a homogeneous layer for PEG-silane but an inhomogeneous distribution for other PEG coatings on the molecularly rough ITO substrates. Atomic force microscopy (AFM) and water contact angle goniometry confirmed the different degrees of surface homogeneity of the polymer films, with PEG-silane reducing the AFM rms surface roughness by 50% and the water contact angle hysteresis by 75% compared to uncoated ITO. The ability of the PEG layers to passivate the substrate against the nonspecific adsorption of biopolymers was tested using fluorescence-labeled immunoglobulin G and DNA oligonucleotides in combination with fluorescence microscopy. The results indicate a positive relationship between film density and homogeneity on one hand and the ability to passivate against biopolymer adhesion on the other hand. The most homogeneous layers prepared with PEG-silane reduced the nonspecific adsorption of fluorescence-labeled DNA by a factor of 300 compared to uncoated ITO. In addition, the study finds that the ratio of film thicknesses derived by ellipsometry and XPS is a useful parameter to quantify the structural integrity of PEG layers on

  3. Effect of block composition on thermal properties and melt viscosity of poly[2-(dimethylaminoethyl methacrylate], poly(ethylene oxide and poly(propylene oxide block co-polymers

    Directory of Open Access Journals (Sweden)

    2011-09-01

    Full Text Available To modify the rheological properties of certain commercial polymers, a set of block copolymers were synthesized through oxyanionic polymerization of 2-(dimethylaminoethyl methacrylate to the chain ends of commercial prepolymers, namely poly(ethylene oxide (PEO, poly(ethylene oxide-block-poly(propylene oxide-block-poly(ethylene oxide (PEO-PPO-PEO, and poly(propylene oxide (PPO. The formed block copolymers were analysed with size exclusion chromatography and nuclear magnetic resonance spectroscopy in order to confirm block formation. Thermal characterization of the resulting polymers was done with differential scanning calorimetry. Thermal transition points were also confirmed with rotational rheometry, which was primarily used to measure melt strength properties of the resulting block co-polymers. It was observed that the synthesised poly[2-(dimethylaminoethyl methacrylate]-block (PDM affected slightly the thermal transition points of crystalline PEO-block but the influence was stronger on amorphous PPO-blocks. Frequency sweeps measured above the melting temperatures for the materials confirmed that the pre-polymers (PEO and PEO-PPO-PEO behave as Newtonian fluids whereas polymers with a PDM block structure exhibit clear shear thinning behaviour. In addition, the PDM block increased the melt viscosity when compared with that one of the pre-polymer. As a final result, it became obvious that pre-polymers modified with PDM were in entangled form, in the melted state as well in the solidified form.

  4. Accumulation of magnetic iron oxide nanoparticles coated with variably sized polyethylene glycol in murine tumors

    DEFF Research Database (Denmark)

    Larsen, Esben Kjær Unmack; Nielsen, Thomas; Wittenborn, Thomas;

    2012-01-01

    polyethylene glycol (PEG). Despite its frequent use, the influence of PEG coatings on the physicochemical and biological properties of iron nanoparticles has hitherto not been studied in detail. To address this, we studied the effect of 333–20 000 Da PEG coatings that resulted in larger hydrodynamic size...

  5. A hydrated phospholipid polymer-grafted layer prevents lipid-related oxidative degradation of cross-linked polyethylene.

    Science.gov (United States)

    Kyomoto, Masayuki; Moro, Toru; Yamane, Shihori; Takatori, Yoshio; Tanaka, Sakae; Ishihara, Kazuhiko

    2017-01-01

    The surface and substrate of a cross-linked polyethylene (CLPE) liner are designed to achieve resistance against oxidative degradation in the construction of hip joint replacements. In this study, we aimed to evaluate the oxidative degradation caused by lipid absorption of a highly hydrophilic nanometer-scaled thickness layer prepared by grafting a poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) layer and a high-dose gamma-ray irradiated CLPE with vitamin E blending (HD-CLPE[VE]). The HD-CLPE(VE) and PMPC-grafted HD-CLPE(VE) exhibited extremely high oxidation resistance regardless of lipid absorption, even though residual-free radical levels were detectable. The water wettability of the PMPC-grafted CLPE and PMPC-grafted HD-CLPE(VE) surfaces was considerably greater than that of untreated surfaces. The hydrated PMPC-grafted layer also exhibited extremely low solubility for squalene. Lipids such as squalene and cholesterol esters diminished the oxidation resistance of CLPE despite the vitamin E improvement. Notably, the PMPC-grafted surface was resistant to lipid absorption and diffusion as well as subsequent lipid-related oxidative degradation, likely because of the presence of the hydrated PMPC-grafted layer. Together, these results provide preliminary evidence that the resistance against lipid absorption and diffusion of a hydrated PMPC-grafted layer might positively affect the extent of resistance to the in vivo oxidation of orthopedic implants.

  6. Thiourea incorporated poly(ethylene oxide) as transparent gel polymer electrolyte for dye sensitized solar cell applications

    Science.gov (United States)

    Pavithra, Nagaraj; Velayutham, David; Sorrentino, Andrea; Anandan, Sambandam

    2017-06-01

    A new series of transparent gel polymer electrolytes are prepared by adding various weight percent of thiourea coupled with poly(ethylene oxide) for the application of dye-sensitized solar cells. Coupling of thiourea in the presence of iodine undergoes dimerization reaction to produce formamidine disulfide. Fourier Transform Infrared spectroscopy shows that the interactions of thiourea and formamidine disulfide with electronegative ether linkage of poly(ethylene oxide) results in conformational changes of gel polymer electrolytes. Electrochemical impedance spectroscopy and linear sweep voltammetry experiments reveal an increment in ionic conductivity and tri-iodide diffusion coefficient, for thiourea modified gel polymer electrolytes. Finally, the prepared electrolytes are used as a redox mediator in dye-sensitized solar cells and the photovoltaic properties were studied. Apart from transparency, the gel polymer electrolytes with thiorurea show higher photovoltaic properties compared to bare gel polymer electrolyte and a maximum photocurrent efficiency of 7.17% is achieved for gel polymer electrolyte containing 1 wt% of thiourea with a short circuit current of 11.79 mA cm-2 and open circuit voltage of 834 mV. Finally, under rear illumination, almost 90% efficiency is retained upon compared to front illumination.

  7. Influence of polyethylene glycol coating on biodistribution and toxicity of nanoscale graphene oxide in mice after intravenous injection

    Directory of Open Access Journals (Sweden)

    Li B

    2014-10-01

    Full Text Available Bo Li,1,2 Xiao-Yong Zhang,1 Jian-Zhong Yang,1 Yu-Jie Zhang,1 Wen-Xin Li,1 Chun-Hai Fan,1 Qing Huang1 1Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 2Department of Human Anatomy, College of Basic Medical Sciences, Jilin University, Changchun, People’s Republic of China Abstract: In this study, we assessed the in vivo behavior and toxicology of nanoscale graphene oxide (NGO in mice after intravenous injection. The influence of a polyethylene glycol (PEG coating on the distribution and toxicity of the NGO was also investigated. The results show that NGO is mainly retained in the liver, lung, and spleen. Retention in the lung is partially due to NGO aggregation. The PEG coating reduces the retention of NGO in the liver, lung, and spleen and promotes the clearance of NGO from these organs, but NGO and NGO-PEG are still present after 3 months. The PEG coating effectively reduces the early weight loss caused by NGO and alleviates NGO-induced acute tissue injuries, which can include damage to the liver, lung, and kidney, and chronic hepatic and lung fibrosis. Keywords: graphene oxide, biodistribution, toxicity, polyethylene glycol

  8. Oxidation-Responsive and "Clickable" Poly(ethylene glycol) via Copolymerization of 2-(Methylthio)ethyl Glycidyl Ether.

    Science.gov (United States)

    Herzberger, Jana; Fischer, Karl; Leibig, Daniel; Bros, Matthias; Thiermann, Raphael; Frey, Holger

    2016-07-27

    Poly(ethylene glycol) (PEG) is a widely used biocompatible polymer. We describe a novel epoxide monomer with methyl-thioether moiety, 2-(methylthio)ethyl glycidyl ether (MTEGE), which enables the synthesis of well-defined thioether-functional poly(ethylene glycol). Random and block mPEG-b-PMTEGE copolymers (Mw/Mn = 1.05-1.17) were obtained via anionic ring opening polymerization (AROP) with molecular weights ranging from 5 600 to 12 000 g·mol(-1). The statistical copolymerization of MTEGE with ethylene oxide results in a random microstructure (rEO = 0.92 ± 0.02 and rMTEG E = 1.06 ± 0.02), which was confirmed by in situ (1)H NMR kinetic studies. The random copolymers are thermoresponsive in aqueous solution, with a wide range of tunable transition temperatures of 88 to 28 °C. In contrast, mPEG-b-PMTEGE block copolymers formed well-defined micelles (Rh ≈ 9-15 nm) in water, studied by detailed light scattering (DLS and SLS). Intriguingly, the thioether moieties of MTEGE can be selectively oxidized into sulfoxide units, leading to full disassembly of the micelles, as confirmed by detection of pure unimers (DLS and SLS). Oxidation-responsive release of encapsulated Nile Red demonstrates the potential of these micelles as redox-responsive nanocarriers. MTT assays showed only minor effects of the thioethers and their oxidized derivatives on the cellular metabolism of WEHI-164 and HEK-293T cell lines (1-1000 μg·mL(-1)). Further, sulfonium PEG polyelectrolytes can be obtained via alkylation or alkoxylation of MTEGE, providing access to a large variety of functional groups at the charged sulfur atom.

  9. Surface modification of polyethylene by radiation-induced grafting for adhesive bonding. III. Oxidative degradation and stabilization of grafted layer

    Energy Technology Data Exchange (ETDEWEB)

    Yamakawa, S.; Yamamoto, F.

    1978-09-01

    Vapor-phase mutual grafting of methyl acrylate (MA) onto polyethylene (PE) and subsequent saponification treatment produce a surface graft having a high adhesive bondability, which results from the presence of a hydrolized homopolymer layer (consisting of only monomer componenet) on an inner graft copolymer layer consisting of both PE and monomer components. The oxidative deterioration and the stabilization of the grated surface layer have been investigated to clarify the long-term stability of the adhesive bondability. The bondability rapidly disappears with accelerated weatherly followed by acetone extraction treatment, whereas it is kept unchanged during thermal-oxidative aging at 100/sup 0/C. Microscopic and attenuated total resonance (ATR) infrared spectroscopic observations of the degreaded surfaces show that the bondability loss is due to degradiative removal of the surface homopolymer layer. The addition of combinations of conventional antioxidants and ultraviolet absorbers stabilizes the grafted surface layer against thermal-oxidative and photo-oxidative degradation and thus extends the bondability rentention time. The stabilization is more effective in the grafts of carbon black-containing PE, where carbon black is present in the inner-graft copolymer layer.

  10. Comparison between Cellulose Nanocrystal and Cellulose Nanofibril Reinforced Poly(ethylene oxide) Nanofibers and Their Novel Shish-Kebab-Like Crystalline Structures

    Science.gov (United States)

    Xuezhu Xu; Haoran Wang; Long Jiang; Xinnan Wang; Scott A. Payne; J.Y. Zhu; Ruipeng Li

    2014-01-01

    Poly(ethylene oxide) (PEO) nanofiber mats were produced by electrospinning. Biobased cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) as reinforcement nanofillers were also added to the polymer to produce composite nanofiber mats. The effects of the two cellulose nanofillers on the rheological properties of the PEO solutions and the microstructure,...

  11. Miscibility of poly(lactic acid) and poly(ethylene oxide) solvent polymer blends and nanofibers made by solution blow spinning

    Science.gov (United States)

    The miscibility of blends of poly(lactic acid) (PLA) and poly(ethylene oxide) (PEO) was studied in polymer solutions by dilute solution viscometry and in solution blow spun nanofibers by microscopy (SEM, TEM) and by thermal and spectral analysis. Three blends of PLA and PEO were solution blended in...

  12. Inhibition of adhesion of yeasts and bacteria by poly(ethylene oxide-)brushes on glass in a parallel plate flow chamber

    NARCIS (Netherlands)

    Roosjen, A.M.; Kaper, H.J.; Mei, van der H.C.; Norde, W.; Busscher, H.J.

    2003-01-01

    Poly(ethylene oxide) (PEO)-brushes are generally recognized as protein-repellent surfaces, and although a role in discouraging microbial adhesion has been established for some strains and species, no study exists on the effects of PEO-brushes on a large variety of bacterial and yeast strains. In thi

  13. Synthesis and Solution Properties of Double Hydrophilic Poly(ethylene oxide)-block-poly(2-ethyl-2-oxazoline) (PEO-b-PEtOx) Star Block Copolymers

    National Research Council Canada - National Science Library

    Tobias Rudolph; Sarah Crotty; Moritz von der Lühe; David Pretzel; Ulrich S Schubert; Felix H Schacher

    2013-01-01

      We demonstrate the synthesis of star-shaped poly(ethylene oxide)-block-poly(2-ethyl-2-oxazoline) [PEOm-b-PEtOxn]x block copolymers with eight arms using two different approaches, either the "arm-first" or the "core-first" strategy...

  14. Structural Evolution of Low-Molecular-Weight Poly(ethylene oxide)-block-polystyrene Diblock Copolymer Thin Film

    Science.gov (United States)

    Huang, Xiaohua

    2013-01-01

    The structural evolution of low-molecular-weight poly(ethylene oxide)-block-polystyrene (PEO-b-PS) diblock copolymer thin film with various initial film thicknesses on silicon substrate under thermal annealing was investigated by atomic force microscopy, optical microscopy, and contact angle measurement. At film thickness below half of the interlamellar spacing of the diblock copolymer (6.2 nm), the entire silicon is covered by a polymer brush with PEO blocks anchored on the Si substrate due to the substrate-induced effect. When the film is thicker than 6.2 nm, a dense polymer brush which is equal to half of an interlamellar layer was formed on the silicon, while the excess material dewet this layer to form droplets. The droplet surface was rich with PS block and the PEO block crystallized inside the bigger droplet to form spherulite. PMID:24302862

  15. Compression Molded Ultra High Molecular Weight Polyethylene-Hydroxyapatite-Aluminum Oxide-Carbon Nanotube Hybrid Composites for Hard Tissue Replacement

    Institute of Scientific and Technical Information of China (English)

    Ankur Gupta; Garima Tripathi; Debrupa Lahiri; Kantesh Balani

    2013-01-01

    Ultra high molecular weight polyethylene (UHMWPE) is widely used for articulating surfaces in total hip and knee replacements.In the present work,UHMWPE based polymer composites were synthesized by synergistic reinforcing of bioactive hydroxyapatite (HA),bioinert aluminum oxide (Al2O3),and carbon nanotubes (CNTs) using compression molding.Phase and microstructural analysis suggests retention of UHMWPE and reinforcing phases in the compression molded composites.Microstructural analysis elicited variation in densification due to the size effect of the reinforcing particles.The hybrid composites exhibited hardness,elastic modulus and toughness comparable to that of UHMWPE.The interfacial effect of reinforcement phases has evinced the effectiveness of Al2O3 over HA and CNT reinforcements,depicting synergistic enhancement in hardness and elastic modulus.Weak interfacial bonding of polymer matrix with HA and CNT requires utilization of coupling agents to achieve enhanced mechanical properties without deteriorating cytocompatible properties.

  16. Assessment of using laponite cross-linked poly(ethylene oxide) for controlled cell adhesion and mineralization.

    Science.gov (United States)

    Gaharwar, Akhilesh K; Schexnailder, Patrick J; Kline, Benjamin P; Schmidt, Gudrun

    2011-02-01

    The in vitro cytocompatibility of silicate (Laponite clay) cross-linked poly(ethylene oxide) (PEO) nanocomposite films using MC3T3-E1 mouse preosteoblast cells was investigated while cell adhesion, spreading, proliferation and mineralization were assessed as a function of film composition. By combining the advantageous characteristics of PEO polymer (hydrophilic, prevents protein and cell adhesion) with those of a synthetic and layered silicate (charged, degradable and potentially bioactive) some of the physical and chemical properties of the resulting polymer nanocomposites could be controlled. Hydration, dissolution and mechanical properties were examined and related to cell adhesion. Overall, this feasibility study demonstrates the ability of using model Laponite cross-linked PEO nanocomposites to create bioactive scaffolds.

  17. The photoluminescence enhancement of electrospun poly(ethylene oxide) fibers with CdS and polyaniline inoculations

    Energy Technology Data Exchange (ETDEWEB)

    Yu Guo [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Li Xiaohong [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)], E-mail: xhli@swjtu.edu.cn; Cai Xiaojun; Cui Wenguo; Zhou Shaobing; Weng Jie [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2008-11-15

    Blending electrospinning of cadmium sulfide (CdS) quantum dots (QD) with poly(ethylene oxide) (PEO) solution was employed to fabricate one-dimensional ultrafine fibers with an average diameter of 450 nm. This study focused on systematic investigations into the role of the matrix polymer and the optimal electrospinning parameters for enhancing the photoluminescence properties of fibrous composites. CdS QDs showed a homogeneous distribution within the composite fibers, and fluorescence spectra showed that PEO successfully passivated the interface defects and quenched the visible emission of CdS QDs. The QDs concentration and electrospinning voltage were found to play important roles in enhancing the passivation effect of PEO and adjusting the photoluminescence intensity of the composite fibers. Furthermore, the addition of polyaniline enhanced the photoluminescence intensity of the electrospun fibers, and an electron-hole mechanism was proposed.

  18. Direct observation of anodic dissolution and filament growth behavior in polyethylene-oxide-based atomic switch structures

    Science.gov (United States)

    Krishnan, Karthik; Tsuruoka, Tohru; Aono, Masakazu

    2016-06-01

    We directly observed anodic dissolution and subsequent filament growth behavior in a planar atomic switch structure with Ag salt incorporated polyethylene oxide (Ag-PEO) film using in situ optical microscopy and ex situ scanning electron microscopy. The high ionic conductivities of Ag-PEO films enable the investigation of filament formation under voltage bias, even in micrometer-scaled devices. It was found that the filament formation changes from unidirectional growth to dendritic growth, depending on its distance from the grounded electrode. Based on this understanding of filament growth dynamics in planar devices, highly stable resistive switching was achieved in an Ag/Ag-PEO/Pt stacked device with an Ag-PEO film thickness of 100 nm. The device showed repeated switching operations for more than 102 sweep cycles, with a high ON/OFF resistance ratio of 105.

  19. Influence of polyethylene glycol coating on biodistribution and toxicity of nanoscale graphene oxide in mice after intravenous injection.

    Science.gov (United States)

    Li, Bo; Zhang, Xiao-Yong; Yang, Jian-Zhong; Zhang, Yu-Jie; Li, Wen-Xin; Fan, Chun-Hai; Huang, Qing

    2014-01-01

    In this study, we assessed the in vivo behavior and toxicology of nanoscale graphene oxide (NGO) in mice after intravenous injection. The influence of a polyethylene glycol (PEG) coating on the distribution and toxicity of the NGO was also investigated. The results show that NGO is mainly retained in the liver, lung, and spleen. Retention in the lung is partially due to NGO aggregation. The PEG coating reduces the retention of NGO in the liver, lung, and spleen and promotes the clearance of NGO from these organs, but NGO and NGO-PEG are still present after 3 months. The PEG coating effectively reduces the early weight loss caused by NGO and alleviates NGO-induced acute tissue injuries, which can include damage to the liver, lung, and kidney, and chronic hepatic and lung fibrosis.

  20. A Novel Synthesis Method of Porous Calcium Silicate Hydrate Based on the Calcium Oxide/Polyethylene Glycol Composites

    Directory of Open Access Journals (Sweden)

    Wei Guan

    2013-01-01

    Full Text Available This paper proposed a novel method to prepare porous calcium silicate hydrate (CSH based on the calcium oxide/polyethylene glycol (CaO/PEG2000 composites as the calcium materials. The porosity formation mechanism was revealed via X-ray diffraction (XRD, field-emission scanning electron microscopy (FESEM, Brunauer-Emmett-Teller (BET, and Fourier transformed infrared spectroscopy (FT-IR. The reactivity of silica materials (SiO2 enhanced by increasing pH value. Ca2+ could not sustain release from CaO/PEG2000 and reacted with caused by silica to form CSH until the hydrothermal temperature reached to 170°C, avoiding the hardly dissolved intermediates formation efficiently. The as-prepared CSH, due to the large specific surface areas, exhibited excellent release capability of Ca2+ and OH−. This porous CSH has potential application in reducing the negative environmental effects of continual natural phosphate resource depletion.

  1. Oxidative-induction time as a measure of vitamin E concentration in ultra-high molecular weight polyethylene.

    Science.gov (United States)

    Heuer, Emily G; Braithwaite, Gavin J C; Miller, Bayen L; Spiegelberg, Stephen H; Gsell, Ray A; Rufner, Alicia S; Stark, Norman

    2015-01-01

    A novel, sensitive method for quantifying an equivalent antioxidant concentration, specifically vitamin E (VE), in postprocessed ultra-high molecular weight polyethylene (UHMWPE) for orthopedic implants is presented. This method correlates oxidative-induction time (OIT) determined from differential scanning calorimetry with starting VE weight percent in solvent blended samples using a nonlinear power law fit. The generated calibration curve reliably determined the equivalent VE concentration down to blended concentrations lower than 0.007 wt %, with a measurement uncertainty of 0.0009 wt %. This measurement uncertainty implies a detection limit that is significantly lower than currently achievable with the established method using Fourier transform infrared spectroscopy to calculate a VE index. However, exact processes that are influencing the OIT in irradiated materials are unclear at this time. UHMWPE blended with VE in powder, consolidated and irradiated form were investigated. In addition, intralaboratory results give support that this technique may lend itself to standardization in quality control and verification.

  2. Analysis of released products from oxidized ultra-high molecular weight polyethylene incubated with hydrogen peroxide and salt solutions.

    Science.gov (United States)

    Lee, A W; Santerre, J P; Boynton, E

    2000-04-01

    The wear of ultra-high molecular weight polyethylene (UHMWPE) implants generates polymeric and metallic particulate, which can be phagocytosed by human macrophages. The generation of these UHMWPE particles has been attributed to wear mechanisms and oxidation of the material. Many cell/particle studies have focused specifically on investigating particles of virgin materials themselves (i.e. virgin UHMWPE), while in fact, there is a strong likelihood that the oxidation processes encountered by the materials will yield particles with very different surface chemistries. Therefore, it is conceivable that chemical changes in the material would lead to altered cellular responses, as measured in the various cell study models. This paper has focused on the characterization of UHMWPE particulates that have been exposed to various conditions simulating processing steps and some of the oxidative and hydrolytic agents related to inflammatory responses. These include gamma-irradiation, thermal treatment and chemical oxidation by H2O2 and saline solutions. Oxidation of the particles was measured using Fourier transform infrared spectroscopy (FTIR). Degradation products were isolated from the incubation solutions using high-performance liquid chromatography (HPLC). UHMWPE particulates underwent extensive oxidation after gamma-irradiation and thermal treatments. There were marked differences following treatments of film samples taken from bar stock and the virgin particle samples. Polymer-related products, containing alkenes, alkanes and hydroxyl groups, were found in the incubation solutions. The study concluded that future work must consider both the particulates' surface chemistry and the possibility of soluble degradation products when assessing UHMWPE/cellular interactions.

  3. Safety of carboxymethylcellulose/polyethylene oxide for the prevention of adhesions in lumbar disc herniation – consecutive case series review

    Directory of Open Access Journals (Sweden)

    Fransen Patrick

    2008-05-01

    Full Text Available Abstract Background Epidural fibrosis is regarded as a cause of failed back surgery syndrome (FBSS when excessive adhesional/fibrotic scar tissue causes compression, pain or discomfort by tethering of nerve tissue to the surrounding muscle or bone. Fibrosis inhibitors could therefore increase the success rate of spinal surgery and decrease the need for reoperations. In recent years, bio-resorbable gels or films for the prevention of peridural fibrosis and post-operative adhesions have been developed that look clinically promising. This included a 100% synthetic, sterile, absorbable gel combinations of carboxymethylcellulose (CMC and polyethylene oxide (PEO used to coat the dura to reduce scarring after discectomy which became available in Europe in 2002. However, given the burden of the problem and unfavorable experience with other types of adhesion-reduction agents, our unit decided to evaluate the safety of CMC/PEO in a large population of patients undergoing spinal microdiscectomy for herniation. Methods To determine the safety and assess efficacy of carboxymethylcellulose/polyethylene oxide (CMC/PEO gel as an anti-adhesion gel, a consecutive series of 396 patients undergoing lumbar discectomy performed by one surgeon had CMC/PEO gel administered at the end of surgery. The patients were followed up in accordance with standard clinical practice and records reviewed for side effects, such as skin reactions, general reactions or local fluid collections. Reoperations for recurrent herniation included an evaluation of fibrosis reduction. Results No product related complications were observed. Five patients needed reoperations for recurrent herniation. Significant but subjective reduction in fibrosis was observed in these patients. Conclusion The findings provide confidence that CMC/PEO gel is well tolerated as an agent to achieve reduction of fibrosis in lumbar disc surgery. Further formal prospective study is recommended in this area of unmet

  4. Synthesis and properties of aromatic polyethers containing poly(ethylene oxide) side chains as polymer electrolytes for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Vöge, Andrea, E-mail: andreavoege@online.de [Department of Chemistry, University of Patras, 26500 Patras (Greece); Deimede, Valadoula, E-mail: deimede@upatras.gr [Department of Chemistry, University of Patras, 26500 Patras (Greece); Paloukis, Fotis; Neophytides, Stylianos G. [Foundation of Research and Technology – Hellas, Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Patras 26504 (Greece); Kallitsis, Joannis K. [Department of Chemistry, University of Patras, 26500 Patras (Greece)

    2014-11-14

    Polymer electrolytes consisting of polar pyridine units in the backbone and poly(ethylene oxide) (PEO) side chains are designed for possible application in lithium ion batteries. In particular, aromatic polyethers bearing PEO side chains with varying length are synthesized either by copolymerization of the corresponding PEO based diols with different arylfluorides or by modification of dihydroxyl functionalized precursor polymers with poly(ethylene oxide) methyl ether tosylate. The formation of free standing films is dependent on the PEO content, polymers' composition as well as on the different monomers used. The mechanical properties study shows that the glass transition temperature can be controlled by varying the PEO content. Thermal stability is also influenced by the PEO length: the shorter the PEO side chain, the higher the stability. XRD analysis gives information about the desired amorphous character of these polymers, which is independent of the PEO content. Solid polymer electrolytes prepared by blending the PEO-based polymers with lithium salt and PEO 2000 (used as plasticizer) show ambient temperature conductivities in the range of 10{sup −6} S/cm. To further improve conductivity doping of PEO-based polymers in liquid electrolyte (1 M LiPF{sub 6} in EC/DMC 1/1) in some cases results in high conductivities in the range of 10{sup −3} S cm{sup −1} at 80 °C. - Highlights: • Polymer electrolytes bearing PEO side chains of varying lengths were designed. • DMA and TGA show that T{sub g} and T{sub d} can be controlled by varying the PEO content. • XRD confirms polymers amorphous character, independent of the PEO content. • Membranes doped in liquid electrolyte have high conductivities (10{sup −3} S cm{sup −1}, 80 °C)

  5. Molecular dynamics study of nanocomposite polymer electrolyte based on poly(ethylene oxide)/LiBF4

    Science.gov (United States)

    Borodin, Oleg; Smith, Grant D.; Bandyopadhyaya, Rajdip; Redfern, Paul; Curtiss, Larry A.

    2004-05-01

    Interactions of Li+ and BF_{4}^{-} ions with TiO2 clusters were investigated using ab initio quantum chemistry methods. Classical force fields have been developed for poly(ethylene oxide)/LiBF4/TiO2, and molecular dynamics simulations have been performed on poly(ethylene oxide)/LiBF4 polymer electrolyte with and without embedded TiO2 nanoparticles using the developed force field. Addition of a TiO2 nanoparticle to PEO/LiBF4 solid polymer electrolyte resulted in the formation of a highly structured layer with a thickness of 5-6 Å that had more than an order of magnitude slower mobility than that of bulk PEO/LiBF4. The PEO and ions in the layers extending from 6 to 15 Å from the TiO2 nanoparticle also revealed some structuring and reduced dynamics, whereas the PEO/LiBF4 located further than 15 Å was basically unaffected by the presence of the TiO2 nanoparticle. Both cations and anions tended to form a region with an increased concentration in the interfacial layers extending from 5 to 15 Å. No ions were dissolved by the first interfacial layer of PEO. Addition of a nanoparticle with soft-repulsion interactions with PEO resulted in the formation of a PEO interfacial layer with reduced PEO density but increased ion concentration. The PEO and ion mobility in the interfacial layer next to the soft-repulsive nanoparticle were higher than those of bulk PEO/LiBF4 by 20-50%, whereas the conductivity of the nanocomposite electrolyte with the soft-repulsive particle increased only by 10%.

  6. Effects of annealing temperature on mechanical durability of indium-tin oxide film on polyethylene terephthalate substrate

    Energy Technology Data Exchange (ETDEWEB)

    Machinaga, Hironobu, E-mail: hironobu_machinaga@gg.nitto.co.jp; Ueda, Eri; Mizuike, Atsuko; Takeda, Yuuki; Shimokita, Keisuke; Miyazaki, Tsukasa

    2014-05-30

    Effects of the annealing temperature on mechanical durability of indium-tin oxide (ITO) thin films deposited on polyethylene terephthalate (PET) substrates were investigated. The ITO films were annealed at the range from 150 °C to 195 °C after the DC sputtering deposition for the production of polycrystalline ITO layers on the substrates. The onset strains of cracking in the annealed ITO films were evaluated by the uniaxial stretching tests with electrical resistance measurements during film stretching. The results indicate that the onset strain of cracking in the ITO film is clearly increased by increasing the annealing temperature. The in-situ measurements of the inter-planer spacing of the (222) plane in the crystalline ITO films during film stretching by using synchrotron radiation strongly suggest that the large compressive stress in the ITO film increases the onset strain of cracking in the film. X-ray stress analyses of the annealed ITO films and thermal mechanical analyses of the PET substrates also clarifies that the residual compressive stress in the ITO film is enhanced with increasing the annealing temperature due to the considerably larger shrinkage of the PET substrate. - Highlights: • Indium-tin oxide (ITO) films were deposited on polyethylene terephthalate (PET). • Mechanical durability of the ITO is improved by high temperature post-annealing. • The shrinkage in the PET increases with rising the post-annealing temperature. • The shrinkage of the PET enhances the compressive stress in the ITO film. • Large compressive stress in the ITO film may improve its mechanical durability.

  7. Poly(ethylene oxide)-block-poly(glutamic acid) coated maghemite nanoparticles: in vitro characterization and in vivo behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Kaufner, L [Department of Anaesthesiology, Charite, Universitaetsmedizin Berlin, Campus Vichow Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Cartier, R [Department of Anaesthesiology, Charite, Universitaetsmedizin Berlin, Campus Vichow Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Wuestneck, R [Department of Anaesthesiology, Charite, Universitaetsmedizin Berlin, Campus Vichow Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Fichtner, I [Max-Delbrueck Center for Molecular Medicine, Robert-Roessle Strasse 10, 13092 Berlin (Germany); Pietschmann, S [Department of Anaesthesiology, Charite, Universitaetsmedizin Berlin, Campus Vichow Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Bruhn, H [Department of Radiology, Charite, Universitaetsmedizin Berlin, Campus Vichow Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Schuett, D [Fraunhofer Institute for Applied Polymer Research, Geiselbergstrasse 69, 14476 Potsdam-Golm (Germany); Thuenemann, A F [Fraunhofer Institute for Applied Polymer Research, Geiselbergstrasse 69, 14476 Potsdam-Golm (Germany); Pison, U [Department of Anaesthesiology, Charite, Universitaetsmedizin Berlin, Campus Vichow Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany)

    2007-03-21

    Positively charged superparamagnetic iron oxide (SPIO) particles of maghemite were prepared in aqueous solution and subsequently stabilized with poly(ethylene oxide)-block-poly(glutamic acid) (PEO-PGA) at a hydrodynamic diameter of 60 nm. Depending on the amount of PEO-PGA used, this is accompanied by a switching of their zeta potentials from positive to negative charge (-33 mV). As a prerequisite for in vivo testing, the PEO-PGA coated maghemite nanoparticles were evaluated to be colloidally stable in water and in physiological salt solution for longer than six months as well in various buffer systems under physiological pH and salt conditions (AFM, dynamic light scattering). We excluded toxic effects of the PEO-PGA coated maghemite nanoparticles. We demonstrated by in vivo MR-imaging and {sup 111}In measurements a biodistribution of the nanoparticles into the liver comparable to carboxydextran coated superparamagnetic iron oxide nanoparticles (Resovist[reg]) as a reference nanoscaled MRI contrast medium. This was enforced by a detailed visualization of our nanoparticles by electron microscopy of liver tissue sections. Furthermore, our results indicate that 15% of the injected PEO-PGA coated maghemite nanoparticles circulate in the blood compartment for at least 60 min after i.v. application.

  8. Effects of UV Aging on the Cracking of Titanium Oxide Layer on Poly(ethylene terephthalate) Substrate: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chao; Gray, Matthew H.; Tirawat, Robert; Larsen, Ross E.; Chen, Fangliang

    2016-04-18

    Thin oxide and metal films deposited on polymer substrates is an emerging technology for advanced reflectors for concentrated solar power applications, due to their unique combination of light weight, flexibility and inexpensive manufacture. Thus far, there is little knowledge on the mechanical integrity or structural persistence of such multi-layer thin film systems under long-term environmental aging. In this paper, the cracking of a brittle titanium dioxide layer deposited onto elasto-plastic poly(ethylene terephthalate) (PET) substrate is studied through a combination of experiment and modeling. In-situ fragmentation tests have been conducted to monitor the onset and evolution of cracks both on pristine and on samples aged with ultraviolet (UV) light. An analytical model is presented to simulate the cracking behavior and to predict the effects of UV aging. Based on preliminary experimental observation, the effect of aging is divided into three aspects and analyzed independently: mechanical property degradation of the polymer substrate; degradation of the interlayer between substrate and oxide coating; and internal stress-induced cracks on the oxide coating.

  9. Correlation between Onset Oxidation Temperature (OOT and Fourier Transform Infrared Spectroscopy (FTIR for monitoring the restabilization of Recycled Low-density Polyethylene (LDPE

    Directory of Open Access Journals (Sweden)

    Adhemar Ruvolo-Filho

    2013-01-01

    Full Text Available In this work a new method was developed for monitoring the oxidative stability of restabilized and non-restabilized low-density polyethylene (LDPE during multiple extrusion cycles. The method is based on correlations between Fourier Transform Infrared spectroscopy (FTIR and Onset Oxidation Temperature (OOT. Non-linear calibration curves correlating the concentration of primary or secondary antioxidants and the OOT values were obtained.

  10. Correlation between Onset Oxidation Temperature (OOT) and Fourier Transform Infrared Spectroscopy (FTIR) for monitoring the restabilization of Recycled Low-density Polyethylene (LDPE)

    Energy Technology Data Exchange (ETDEWEB)

    Ruvolo-Filho, Adhemar; Pelozzi, Tadeu Luiz Alonso, E-mail: adhemar@power.ufscar.br [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Departamento de Quimica

    2013-07-01

    In this work a new method was developed for monitoring the oxidative stability of restabilized and non-restabilized low-density polyethylene (LDPE) during multiple extrusion cycles. The method is based on correlations between Fourier Transform Infrared Spectroscopy (FTIR) and Onset Oxidation Temperature (OOT). Non-linear calibration curves correlating the concentration of primary or secondary antioxidants and the OOT values were obtained. (author)

  11. One-step sonochemical synthesis of a graphene oxide-manganese oxide nanocomposite for catalytic glycolysis of poly(ethylene terephthalate).

    Science.gov (United States)

    Park, Gle; Bartolome, Leian; Lee, Kyoung G; Lee, Seok Jae; Kim, Do Hyun; Park, Tae Jung

    2012-07-07

    Ultrasound-assisted synthesis of a graphene oxide (GO)-manganese oxide nanocomposite (GO-Mn(3)O(4)) was conducted without further modification of GO or employing secondary materials. With the GO nanoplate as a support, potassium permanganate oxidizes the carbon atoms in the GO support and gets reduced to Mn(3)O(4). An intensive ultrasound method could reduce the number of reaction steps and temperature, enhance the reaction rate and furthermore achieve a Mn(3)O(4) phase. The composite was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The coverage and crystallinity of Mn(3)O(4) were controlled by changing the ratio of permanganate to GO dispersion. The synthesized nanocomposite was used as a catalyst for poly(ethylene terephthalate) (PET) depolymerization into its monomer, bis(2-hydroxylethyl) terephthalate (BHET). The highest monomer yield of 96.4% was obtained with the nanocomposite containing the lowest amount of Mn(3)O(4), while PET glycolysis with the Mn(3)O(4) without GO yielded 82.7% BHET.

  12. Poly(ethylene oxide) Solubilization in Reverse Microemulsion: Conductivity and UV-Vis Spectra Studies

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The effect of poly (ethylene oxide) (PEO) on the w/o microemulsion is studied. The addition of PEO induces a decrease of attractive interaction between droplets in reverse microemulsion. Due to the absence of interaction between cationic surfactant and neutral polymer, the polymer molecules are forced into the interior of water core, avoiding the interfacial region.

  13. Fabrication and study of properties of magnetite nanoparticles in hybrid micelles of polystyrene-block-polyethylene oxide and sodium dodecyl sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Loginova, T. P., E-mail: tlg@ineos.ac.ru; Timofeeva, G. I.; Lependina, O. L.; Shandintsev, V. A. [Russian Academy of Sciences, Nesmeyanov Institute of Organoelement Compounds (Russian Federation); Matyushin, A. A. [Ministry of Public Health of the Russian Federation, First Moscow State Medical University (Russian Federation); Khotina, I. A. [Russian Academy of Sciences, Nesmeyanov Institute of Organoelement Compounds (Russian Federation); Shtykova, E. V. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

    2016-01-15

    Magnetite nanoparticles have been formed for the first time in hybrid micelles of polystyrene-block-polyethylene oxide and sodium dodecyl sulfate in water by ultrasonic treatment at room temperature. An analysis by small-angle X-ray scattering and transmission electron microscopy (TEM) showed that magnetite nanoparticles in hybrid micelles of block copolymer and sodium dodecyl sulfate are polydesperse (have sizes from 0.5 to 20 nm). The specific magnetization of solid samples has been measured.

  14. RGDS-functionalized polyethylene glycol hydrogel-coated magnetic iron oxide nanoparticles enhance specific intracellular uptake by HeLa cells

    OpenAIRE

    Nazli C; Ergenc TI; Yar Y; Acar HY; Kizilel S

    2012-01-01

    © 2012 Nazli et al, publisher and licensee Dove Medical Press Ltd. This is an Open Access article which permits unrestricted noncommercial use, provided the original work is properly cited. International Journal of Nanomedicine 2012:7 1903–1920 International Journal of Nanomedicine RGDS-functionalized polyethylene glycol hydrogel-coated magnetic iron oxide nanoparticles enhance specific intracellular uptake by HeLa cells Caner Nazli1 Tugba Ipek Ergenc2 Yasemin Ya...

  15. To immobilize polyethylene glycol-borate ester/lithium fluoride in graphene oxide/poly(vinyl alcohol) for synthesizing new polymer electrolyte membrane of lithium-ion batteries

    OpenAIRE

    Huang, Y.F.; Zhang, M. Q.; M. Z. Rong; W. H. Ruan

    2017-01-01

    Polymer electrolyte membranes (PEMs) are potentially applicable in lithium-ion batteries with high safety, low cost and good performance. Here, to take advantages of ionic conductivity and selectivity of borate ester-functionalized small molecules as well as structural properties of polymer nanocomposite, a strategy of immobilizing as-synthesized polyethylene glycol-borate ester/lithium fluoride (B-PEG/LiF) in graphene oxide/poly(vinyl alcohol) (GO/PVA) to prepare a PEM is put forward. Chemic...

  16. Synthesis and Properties of High Strength Thin Film Composites of Poly(ethylene Oxide) and PEO-PMMA Blend with Cetylpyridinium Chloride Modified Clay

    OpenAIRE

    Mohammad Saleem Khan; Sabiha Sultana

    2015-01-01

    Ion-conducting thin film composites of polymer electrolytes were prepared by mixing high MW poly(ethylene oxide) (PEO), poly(methyl methacrylate) (PMMA) as a polymer matrix, cetylpyridinium chloride (CPC) modified MMT as filler, and different content of LiClO4 by using solution cast method. The crystallinity, ionic conductivity (σ), and mechanical properties of the composite electrolytes and blend composites were evaluated by using XRD, AC impedance, and UTM studies, respectively. The modific...

  17. Nuclear Magnetic Resonance Investigation of Dynamics in Poly(Ethylene Oxide) Based Lithium Polyether-ester-sulfonate Ionomers

    Energy Technology Data Exchange (ETDEWEB)

    Roach, David J.; Dou, Shichen; Colby, Ralph H.; Mueller, Karl T.

    2012-01-07

    Nuclear magnetic resonance (NMR) spectroscopy has been utilized to investigate the dynamics of poly(ethylene oxide)-based lithium sulfonate ionomer samples that have low glass transition temperatures. 1H and 7Li spin-lattice relaxation times (T1) of the bulk polymer and lithium ions, respectively, were analyzed in samples with a range of ion contents. The temperature dependence of T1 values along with the presence of minima in T1 enabled correlation times and activation energies to be obtained for both the segmental motion of the polymer backbone and the hopping motion of lithium cations. Similar activation energies of both the polymer and lithium ions in the lower ion content samples indicate that the polymer segmental motion and lithium ion hopping motion are correlated even though their respective correlation times differ significantly. A divergent trend is observed for correlation times and activation energies of the highest ion content sample due to the presence of ionic aggregation. Details about the polymer and cation dynamics on the nanosecond timescale are discussed and complement the findings of X-ray scattering and Quasi Elastic Neutron Scattering experiments.

  18. Lipoprotein interactions with a polyurethane and a polyethylene oxide-modified polyurethane at the plasma-material interface.

    Science.gov (United States)

    Cornelius, Rena M; Macri, Joseph; Cornelius, Katherine M; Brash, John L

    2016-06-15

    Lipoproteins [high density lipoprotein (HDL), low density lipoprotein (LDL), and very low density lipoprotein (VLDL)] are present in blood in relatively high concentrations, and, given their importance in cardiovascular disease, the interactions of these species with blood contacting biomaterials and their possible role in thrombogenesis is of interest. In the present communication, quantitative data on the adsorption of apolipoprotein AI, apolipoprotein AII (the main protein components of HDL), and apolipoprotein B (the main protein component of LDL and VLDL), as well as the lipoproteins themselves from plasma to a biomedical grade polyurethane (PU) with and without a copolymer additive that contains polyethylene oxide (PEO) segments, were investigated. Adsorption from some binary solutions was also studied. Significant quantities of the apolipoproteins were found to adsorb from plasma to the PU, while adsorption to the PEO material was more than 90% lower, demonstrating strong protein resistance of the latter material. In contrast, significant quantities of the lipoproteins were found to adsorb to the PEO as well as to the PU material. From these and previously published results, it is concluded that the protein layer formed on the PU surface from plasma (and by extension from blood) contains apolipoproteins and lipoproteins in addition to other plasma proteins; the layer formed on the PEO surface, however, appears to contain minimal quantities of plasma proteins (including free apolipoproteins) but significant quantities of lipoproteins.

  19. Preparation of Pure and Stable Chitosan Nanofibers by Electrospinning in the Presence of Poly(ethylene oxide).

    Science.gov (United States)

    Mengistu Lemma, Solomon; Bossard, Frédéric; Rinaudo, Marguerite

    2016-10-26

    Electrospinning was employed to obtain chitosan nanofibers from blends of chitosans (CS) and poly(ethylene oxide) (PEO). Blends of chitosan (MW (weight-average molecular weight) = 102 kg/mol) and PEO (M (molecular weight) = 1000 kg/mol) were selected to optimize the electrospinning process parameters. The PEO powder was solubilized into chitosan solution at different weight ratios in 0.5 M acetic acid. The physicochemical changes of the nanofibers were determined by scanning electron microscopy (SEM), swelling capacity, and nuclear magnetic resonance (NMR) spectroscopy. For stabilization, the produced nanofibers were neutralized with K₂CO₃ in water or 70% ethanol/30% water as solvent. Subsequently, repeated washings with pure water were performed to extract PEO, potassium acetate and carbonate salts formed in the course of chitosan nanofiber purification. The increase of PEO content in the blend from 20 to 40 w% exhibited bead-free fibers with average diameters 85 ± 19 and 147 ± 28 nm, respectively. Their NMR analysis proved that PEO and the salts were nearly completely removed from the nanostructure of chitosan, demonstrating that the adopted strategy is successful for producing pure chitosan nanofibers. In addition, the nanofibers obtained after neutralization in ethanol-aqueous solution has better structural stability, at least for six months in aqueous solutions (phosphate buffer (PBS) or water).

  20. Processing of Micro and Nanofibers of Polypyrrole/Polyethylene Oxide/Nylon-6 by the Technique of Electrospinning

    Directory of Open Access Journals (Sweden)

    Olvera-Gracia Manuel

    2013-10-01

    Full Text Available Micro and nano-fibers from polymers in solution can be easily obtained by using the so called electrospinning technique. The principle of this technique relies on apply- ing a positive voltage to the polymer solution and a negative voltage to a collector. By increasing voltage, the surface tension will be overcome and will eject some kind of fiber deposited on the collector. The continuous fibers production will be formed like a membrane. The fibers provide a large surface area due to their small diameter, therefore, their application is considered of commercial and scientific interest. In this study, fibers from a solution made of nylon-6, polyethylene oxide and polypyrrole were obtained. Chloroform and formic acid were used as solvents for these polymers. The fibers obtained were characterized by scanning electron microscopy, FT-IR spectroscopy, X-ray diffraction and electrical conductivity. These results indicate that the diameters of the composite fibers are on the micro and nanometric range, and the conductivity thereof is that of a semiconductor material.

  1. A comparison of united atom, explicit atom, and coarse-grained simulation models for poly(ethylene oxide).

    Science.gov (United States)

    Chen, Chunxia; Depa, Praveen; Sakai, Victoria García; Maranas, Janna K; Lynn, Jeffrey W; Peral, Inmaculada; Copley, John R D

    2006-06-21

    We compare static and dynamic properties obtained from three levels of modeling for molecular dynamics simulation of poly(ethylene oxide) (PEO). Neutron scattering data are used as a test of each model's accuracy. The three simulation models are an explicit atom (EA) model (all the hydrogens are taken into account explicitly), a united atom (UA) model (CH(2) and CH(3) groups are considered as a single unit), and a coarse-grained (CG) model (six united atoms are taken as one bead). All three models accurately describe the PEO static structure factor as measured by neutron diffraction. Dynamics are assessed by comparison to neutron time of flight data, which follow self-motion of protons. Hydrogen atom motion from the EA model and carbon/oxygen atom motion from the UA model closely follow the experimental hydrogen motion, while hydrogen atoms reinserted in the UA model are too fast. The EA and UA models provide a good description of the orientation properties of C-H vectors measured by nuclear magnetic resonance experiments. Although dynamic observables in the CG model are in excellent agreement with their united atom counterparts, they cannot be compared to neutron data because the time after which the CG model is valid is greater than the neutron decay times.

  2. Poly(ethylene oxide) irradiated in the solid state, melt and aqueous solution—a DSC and WAXD study

    Science.gov (United States)

    Jurkin, Tanja; Pucić, Irina

    2012-09-01

    Interactions of the aggregate state of poly(ethylene oxide), PEO, and γ-irradiation conditions (total dose, atmosphere) on its thermal and crystalline properties were investigated by DSC and WAXD taking into account sample molecular mass and form. In PEO irradiated in the solid state and in the presence of oxygen, chain scission dominated over concurrent crosslinking up to 200 kGy, particularly in PEO powders, due to a large surface being in contact with air. In solid samples the degree of crystallinity and crystallite size increased with the dose up to 50 kGy, probably not just due to partial crystallization upon degradation of amorphous phase, but to recrystallization of broken tie molecules. The least changes in crystallinity and phase transformation temperatures occurred in solid films. A substantial decrease in crystallinity and transformation temperatures without the initial crystallinity increase was achieved in samples that were amorphous on irradiation, at temperatures above the PEO melting temperature and in aqueous solutions. Radiation crosslinking of the PEO aqueous solution in an inert atmosphere is the most suitable way to obtain a lower degree of crystallinity and phase transformation temperatures while preserving mechanical properties.

  3. Effects of 12-Crown-4 ether on the ionic conductivity and electrode kinetics of electrolytes in polyethylene oxide

    Science.gov (United States)

    Nagasubramanian, G.; di Stefano, S.

    Results are described of investigations of the electrical and electrochemical properties of thin films of polyethylene oxide (PEO) electrolytes with and without 12-Crown-4 ether (12Cr4) as a function of temperature and in the frequency regime 100 kHz-0.1 Hz. These measurements were made for LiCF3SO3, LiBF4, and LiClO4 salts. At a given temperature, the bulk conductivity, sigma, (S/cm), for a particular salt, depends on the 12Cr4 concentration with sigma reaching a maximum at about 3 mM 12Cr4. Of the three salts studied, the sigma is the highest for PEO/LiBF4 with 3 mM 12Cr4. The ac and dc measurements yield a lower charge transfer resistance for 12Cr4-incorporated samples than for samples without. Plating/stripping of Li occurs at a potential closer to Li(+)/Li for 12Cr4 samples than those without. The conductivities of a thin (about 100 microns) and a thick (400 microns) films are similar.

  4. Poly(ethylene oxide)-Based Composite Electrolytes Filled with Periodic Mesoporous Silica for Solid State Ionics

    Science.gov (United States)

    Tominaga, Yoichi; Morita, Masahiro; Asai, Shigeo; Sumita, Masao

    Mesoporous silica (MPS) was used for poly(ethylene oxide) (PEO)-based solid polymer electrolytes as novel inorganic filler. For improvement in ionic conductivity in solid state, a room temperature ionic liquid (IL), 1-ethyl-3-methylimidazolium tetrafluoroborate, was introduced into periodic nano-tunnels of MPS, and the modified MPS (IL-MPS) was filled with PEO-LiBF4 electrolyte. Ionic conductivity of neat-MPS-filled composites was approximately 4-fold higher than that of the original electrolyte. On the other hand, the conductivity was more than 11-fold enhanced by addition of IL-MPS, to be more than 10-6 S/cm at 30°C and at least 10 wt% silica contents. The conductivity increased with increasing IL-MPS contents, to be a maximum value of approximately 3×10-6 S/cm at 30°C and at 40 wt%. Dynamic mechanical measurements for neat- and IL-MPS composites revealed that the addition of fillers improves storage modulus of PEO-based electrolytes at room temperature. The addition of IL-MPS was able to realize the improvement in both ionic conductivity and storage modulus.

  5. Controlled protein release from electrospun biodegradable fiber mesh composed of poly(epsilon-caprolactone) and poly(ethylene oxide).

    Science.gov (United States)

    Kim, Taek Gyoung; Lee, Doo Sung; Park, Tae Gwan

    2007-06-29

    A blend mixture of poly(epsilon-caprolactone) (PCL) and poly(ethylene oxide) (PEO) was electrospun to produce fibrous meshes that could release a protein drug in a controlled manner. Various biodegradable polymers, such as poly(l-lactic acid) (PLLA), poly(epsilon-caprolactone) (PCL), and poly(d,l-lactic-co-glycolic acid) (PLGA) were dissolved, along with PEO and lysozyme, in a mixture of chloroform and dimethylsulfoxide (DMSO). The mixture was electrospun to produce lysozyme loaded fibrous meshes. Among the polymers, the PCL/PEO blend meshes showed good morphological stability upon incubation in the buffer solution, resulting in controlled release of lysozyme over an extended period with reduced initial bursts. With varying the PCL/PEO blending ratio, the release rate of lysozyme from the corresponding meshes could be readily modulated. The lysozyme release was facilitated by increasing the amount of PEO, indicating that entrapped lysozyme was mainly released out by controlled dissolution of PEO from the blend meshes. Lysozyme released from the electrospun fibers retained sufficient catalytic activity.

  6. Vibrational spectroscopic study of ionic association in poly(ethylene oxide)-NH4SCN polymer electrolytes.

    Science.gov (United States)

    Zhang, Hucheng; Wang, Jianji

    2009-01-01

    The polymer-ammonium complexes are an important class of proton conducting polymer electrolytes. In this work, poly(ethylene oxide) (PEO)-NH(4)SCN electrolytes were prepared over a large range of the salt content, and their FT-IR spectra were measured at room temperature. Based on the assignments of each band in the spectral envelope of SCN(-1), their relative intensities are determined by the use of FT-IR technique. Following the experimental results and spectral analyses, this paper reports the interactions, the various ionic associations, the changes of the ionic association with NH(4)SCN content, and the characteristics of structure in PEO-NH(4)SCN electrolytes. It is shown that the hydrogen bonds of PEO and NH(4)SCN exert the great effect to the ionic association, the interactions of PEO with NH(4)SCN, and PEO crystallinity, in particular, under the condition of high NH(4)SCN content. In addition, the differences of ionic association among PEO-NaSCN, PEO-KSCN and NH(4)SCN electrolytes are also compared in this paper.

  7. Charge transport and glassy dynamics of poly(ethylene oxide)-based single-ion conductors under geometrical confinement

    Science.gov (United States)

    Runt, James; Iacob, Ciprian

    2015-03-01

    Segmental and local dynamics as well as charge transport are investigated in a series of poly(ethylene oxide)-based single-ion conductors (ionomers) with varying counterions (Li +, Na +) confined in uni-directional nanoporous silica membranes. The dynamics are explored over a wide frequency and temperature range by broadband dielectric relaxation spectroscopy. Slowing of segmental dynamics and a decrease in dc conductivity (strongly coupled with segmental relaxation) of the confined ionomers are associated with surface effects - resulting from interfacial hydrogen bonding between the host nanoporous silica membrane and the guest ionomers. These effects are significantly reduced or eliminated upon pore surface modification through silanization. The primary transport properties for the confined ionomers decrease by about one decade compared to the bulk ionomer. A model assuming reduced mobility of an adsorbed layer at the pore wall/ionomer interface is shown to provide a quantitative explanation for the decrease in effective transport quantities in non-silanized porous silica membranes. Additionally, the effect of confinement on ion aggregation in ionomers by using X-ray scattering will also be discussed. Supported by the National Science Foundation, Polymers Program.

  8. Understanding the Impact of Poly(ethylene oxide) on the Assembly of Lignin in Solution toward Improved Carbon Fiber Production.

    Science.gov (United States)

    Imel, Adam E; Naskar, Amit K; Dadmun, Mark D

    2016-02-10

    Carbon fiber produced from lignin has recently become an industrial scalable product with applications ranging from thermal insulation to reinforcing automobile bodies. Previous research has shown that mixing 1-2 wt %, of poly(ethylene oxide) (PEO) with the lignin before fiber formation can enhance the properties of the final carbon fibers. The research reported here determines the impact of adding PEO to a lignin solution on its assembly, focusing on the role of the lignin structure on this assembly process. Results indicate the addition of PEO anisotropically directs the self-assembly of the hardwood and softwood lignin by lengthening the cylindrical building blocks that make up the larger global aggregates. On the other hand, results from an annual lignin exhibit a shapeless, more complex structure with a unique dependence on the PEO loading. These results are consistent with improved carbon fibers from solutions of lignin that include PEO, as the local ordering and directed assembly will inhibit the formation of defects during the carbon fiber fabrication process.

  9. CRYSTALLIZATION AND MELTING OF POLY(ETHYLENE OXIDE) CONFINED IN NANOSTRUCTURED PARTICLES WITH CROSS-LINKED SHELLS OF POLYBUTADIENE

    Institute of Scientific and Technical Information of China (English)

    Wei-ping Gao; Yu Bai; Er-qiang Chen; Qi-feng Zhou

    2005-01-01

    Small fixed aggregates of a poly(ethylene oxide)-block-polybutadiene diblock copolymer (PEO-b-PB) in THF solution were obtained by adding a selective solvent for PB blocks, followed by cross-linking the PB shells. The morphologies of the nanostructured particles with a cross-linked shell were investigated by atomic force microscopy and transmission electron microscopy. The average behaviors of the PEO crystallization and melting confined within the nanostructured particles were studied by using differential scanning calorimetry experiments. For the deeply cross-linked sample (SCL-l), the crystallization of the PEO blocks was fully confined. The individual nanoparticles only crystallized at very low crystallization temperatures (TcS), wherein the homogenous primary nucleation determined the overall crystallization rate. For the lightly cross-linked sample (SCL-2), the confinement effect was Tc dependent. At Tc ≤ 42℃, the crystallization and melting behaviors of SCL-2 were similar to those of the pure PEO-b-PB diblock copolymer. At Tc > 42℃,SCL-2 could form PEO lamellae thicker than those of the pure PEO-b-PB crystallized at the same Tc.

  10. SPECT/CT Imaging of Pluronic Nanocarriers with Varying Poly(ethylene oxide) Block Length and Aggregation State.

    Science.gov (United States)

    Arranja, Alexandra; Ivashchenko, Oleksandra; Denkova, Antonia G; Morawska, Karolina; van Vlierberghe, Sandra; Dubruel, Peter; Waton, Gilles; Beekman, Freek J; Schosseler, François; Mendes, Eduardo

    2016-03-07

    Optimal biodistribution and prolonged circulation of nanocarriers improve diagnostic and therapeutic effects of enhanced permeability and retention-based nanomedicines. Despite extensive use of Pluronics in polymer-based pharmaceuticals, the influence of different poly(ethylene oxide) (PEO) block length and aggregation state on the biodistribution of the carriers is rather unexplored. In this work, we studied these effects by evaluating the biodistribution of Pluronic unimers and cross-linked micelles with different PEO block size. In vivo biodistribution of (111)In-radiolabeled Pluronic nanocarriers was investigated in healthy mice using single photon emission computed tomography. All carriers show fast uptake in the organs from the reticuloendothelial system followed by a steady elimination through the hepatobiliary tract and renal filtration. The PEO block length affects the initial renal clearance of the compounds and the overall liver uptake. The aggregation state influences the long-term accumulation of the nanocarriers in the liver. We showed that the circulation time and elimination pathways can be tuned by varying the physicochemical properties of Pluronic copolymers. Our results can be beneficial for the design of future Pluronic-based nanomedicines.

  11. Polymer-Ion Interaction Weakens the Strain-Rate Dependence of Extension-Induced Crystallization for Poly(ethylene oxide).

    Science.gov (United States)

    Hu, Tingting; Tian, Nan; Ali, Sarmad; Wang, Zhen; Chang, Jiarui; Huang, Ningdong; Li, Liangbin

    2016-03-01

    The crystallization of poly(ethylene oxide) (PEO)-sodium iodine (NaI) composites is investigated by differential scanning calorimetry (DSC), extensional rheology, and in situ small-angle X-ray scattering (SAXS) with the aim of demonstrating versatile roles played by polymer-ion interactions. In the isothermal quiescent crystallization process, a decrease in the crystal growth rate is observed for PEO-NaI and is attributed to slow chain movement caused by the coordination between cations and polymer. In situ SAXS on extensional flow-induced crystallization (FIC) exhibits enhanced kinetics and orientation for both PEO and PEO-NaI with increasing strain rate. However, an overall weaker strain-rate dependence of FIC is observed for PEO-NaI, which can be interpreted as a synergistic consequence of promoted nucleation under flow and impeded crystal growth by polymer-ion interaction. A possible microscopic mechanism is proposed to account for the experimental observation based on the formation of transient cross-linking points in PEO-NaI and their influence on the entanglement network of polymer under various flow fields. The disclosed strain-rate dependence and various ion effects on the behavior of PEO-salt composites contribute to a comprehensive understanding of polymer-ion solid polyelectrolytes.

  12. Influence of defects and processing parameters on the properties of indium tin oxide films on polyethylene napthalate substrate

    Science.gov (United States)

    Han, H.; Zoo, Yeongseok; Bhagat, S. K.; Lewis, J. S.; Alford, T. L.

    2007-09-01

    Indium tin oxide (ITO) thin films were deposited on polyethylene napthalate (PEN) by rf sputtering using different rf powers (60 and 120W) and at different substrate temperatures (room temperature and 100°C). Selected PEN substrates were pretreated using an Ar plasma before ITO sputter deposition. Rutherford backscattering spectrometry was used to determine the oxygen content in the films. Hall effect measurements were used to evaluate the electrical properties. In this paper the influence of defect structure, sputtering conditions, and the effect of annealing on the electrical and optical properties of ITO on PEN have been investigated. Electrical properties such as carrier concentration, mobility, and resistivity of the ITO films varied with rf power and substrate temperature. The electrical and optical properties of the films changed after annealing in air. This study also describes how the as-deposited amorphous ITO changes from amorphous to crystalline as a result of heat treatment, and investigates the effects of Sn defect clustering on electrical and optical properties of the ITO films.

  13. EFFECTS OF NH4CI ON THE INTERACTION BETWEEN POLY(ETHYLENE OXIDE)AND IONIC SURFACTANTS IN AQUEOUS SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The interaction of poly(ethylene oxide)(PEO)with the ionic surfactants,sodium dodecylsulfate(SDS)and cetyltrimethylammonium chloride(CTAC)respectively,in aqueous solutions containing a certain concentration of NH4Cl,is studied by the viscosity measurement.It has been found that the ion-dipole interaction between PEO and ionic surfactants is changed considerably by the organic salt.For anionic surfactant of SDS,the addition of NH4Cl into solution strengthens the interaction between PEO and the headgroup of SDS.On the other hand,for cationic surfactant of CTAC,the interaction between PEO and the headgroup of CTAC is screened significantly by NH4Cl dissolved in solution.These findings may potentially be attributed to the negative property of the oxygen group of the PEO chain.In the presence of NH4Cl,the cationic ions of the organic salt bind to the oxygen group of the PEO chain so that PEO can be referred to as a pseudopolyelectrolyte in solution.

  14. Enhanced luminescence properties of highly threaded conjugated polyelectrolytes with potassium counter-ions upon blending with poly(ethylene oxide)

    Science.gov (United States)

    Latini, Gianluca; Winroth, Gustaf; Brovelli, Sergio; McDonnell, Shane O.; Anderson, Harry L.; Mativetsky, Jeffrey M.; Samorı, Paolo; Cacialli, Franco

    2010-06-01

    The photophysics and electroluminescence (EL) of thin films of unthreaded and cyclodextrin-encapsulated poly(4,4'-diphenylenevinylene) (PDV) with potassium countercations, blended with poly(ethylene oxide) (PEO) are investigated as a function of the PEO concentration. We show that three main factors contribute to increasing the photoluminescence (PL) quantum efficiency as a result of suppressed intermolecular interactions, namely: the high degree of encapsulation of the polyrotaxanes, the relatively large countercation (e.g., compared to lithium), and the complexation of the rotaxanes with PEO. By facilitating cationic transport to the negative electrodes, PEO also leads to devices with enhanced electron injection and improved charge balance, whose operation therefore resembles that of "virtually unipolar" light-emitting electrochemical cells. This effect, together with the enhanced PL efficiency, leads to higher EL efficiency for both polyrotaxanes and unthreaded polymers, upon addition of the PEO. We show that the concurrent exploitation of the various strategies above lead to an overall EL efficiency that is approximately twice the value previously reported for Li-based PDV. A blueshift of the EL spectrum during the devices turn-on is also reported and analyzed in terms of interference and doping effects.

  15. Nanofibrous Chitosan-Polyethylene Oxide Engineered Scaffolds: A Comparative Study between Simulated Structural Characteristics and Cells Viability

    Directory of Open Access Journals (Sweden)

    Mohammad Kazemi Pilehrood

    2014-01-01

    Full Text Available 3D nanofibrous chitosan-polyethylene oxide (PEO scaffolds were fabricated by electrospinning at different processing parameters. The structural characteristics, such as pore size, overall porosity, pore interconnectivity, and scaffold percolative efficiency (SPE, were simulated by a robust image analysis. Mouse fibroblast cells (L929 were cultured in RPMI for 2 days in the presence of various samples of nanofibrous chitosan/PEO scaffolds. Cell attachments and corresponding mean viability were enhanced from 50% to 110% compared to that belonging to a control even at packed morphologies of scaffolds constituted from pores with nanoscale diameter. To elucidate the correlation between structural characteristics within the depth of the scaffolds’ profile and cell viability, a comparative analysis was proposed. This analysis revealed that larger fiber diameters and pore sizes can enhance cell viability. On the contrary, increasing the other structural elements such as overall porosity and interconnectivity due to a simultaneous reduction in fiber diameter and pore size through the electrospinning process can reduce the viability of cells. In addition, it was found that manipulation of the processing parameters in electrospinning can compensate for the effects of packed morphologies of nanofibrous scaffolds and can thus potentially improve the infiltration and viability of cells.

  16. Dielectric and Mechanical Investigations on the Hydrophilicity and Hydrophobicity of Polyethylene Oxide Modified on a Silicon Surface.

    Science.gov (United States)

    Shang, Jing; Hong, Kunlun; Wang, Tao; Zhu, Dan; Shen, Jian

    2016-11-08

    Polyethylene oxide (PEO) has been widely used in biomedical fields. The antibiofouling property of the PEO-modified surface has been extensively investigated but is far from being fully understood. A series of PEOs with narrowly distributed molecular weight (Mw), synthesized with the technique of high vacuum anionic polymerization, have been successfully grafted onto the surface of silicon wafers. The power-law relationship between the thickness of the monolayer versus the Mw of the grafted PEO shows a scaling of 0.3, indicating compact condensing of the chains. The static contact angles show higher hydrophobicity for the layer of PEO with higher Mw, which can be attributed to the closely packed conformation of the chains with high density. The frequency shift of the contact resonance indicates that the Young's modulus decreases and the loss factor increases with the increase in the Mw of PEO and the thickness of the PEO layers. Dielectric spectroscopy of bare or PEO-grafted wafers in the aqueous solutions reveals an interfacial polarization, which results from compositional and structural changes in the interface layer and depends on temperatures and salt concentrations. At a given grafting density, the PEO chains are swollen in pure water, demonstrating hydrophilic behavior, whereas they collapse in salt solutions, showing hydrophobic characteristics.

  17. A Study of the Deformation, Network, and Aging of Polyethylene Oxide Films by Infrared Spectroscopy and Calorimetric Measurements

    Directory of Open Access Journals (Sweden)

    Carl Bergeron

    2012-01-01

    Full Text Available The calorimetric and infrared (IR spectroscopy measurements of polyethylene oxide (PEO are used to evaluate the deformation and relaxation that films experience during a temperature cycle (30°C–90°C–30°C. After melting, the intensity of some bands decreases by 10 to 70%. During the temperature cycle, the C–O band in the 1100 cm−1 region and the C–C–O deformation bands at 650 and 500 cm−1 show some new features. A network of cooperative oxygen-hydrogen interactions between the PEO chains form in films with special history, namely, in thermally treated films, in thin films prepared from gel forming solutions, and in thick films after aging. The interchain interaction network is suggested from the IR absorption bands in the 1200 and 900 cm−1 region and also from small bands at 1144 and 956 cm−1. The network seems absent or reduced in thin films. IR spectroscopy appears a sensitive technique to study chain conformations in PEO films and in other materials where order, disorder, and the formation of intermolecular interactions coexist.

  18. Poly(ethylene imine)-modified graphene oxide with improved colloidal stability and its adsorption of methyl orange.

    Science.gov (United States)

    Liu, Hongxi; Wu, Ting; Wu, Zhimin; Zhang, Yong; Xuan, Keqin; Zhang, Jinglin; Tan, Shaozao

    2014-01-01

    Graphene oxide (GO) was chemically modified with poly(ethylene imine) (PEI) to improve its colloidal stability and was investigated as a potential adsorbent for the removal of methyl orange (MO). The synthesis of PEI-GO was verified with a Fourier transform infrared spectrometer and thermogravimetric analysis. A series of adsorption experiments were carried out to investigate the adsorption capacity of PEI-GO. Adsorption kinetics and thermodynamics studies were performed, and the thermodynamic parameters were calculated. The results showed that PEI could improve the colloidal stability of GO in aqueous solution, and the obtained PEI-GO showed a macroscopically homogeneous dispersion after more than three months. After standing for 90 days, the Brunauer-Emmett-Teller specific surface area of GO decreased from 353 to 214 m2·g(-1), while that of PEI-GO remained almost unchanged (from 432 to 413 m2·g(-1)). The PEI-GO exhibited significantly faster kinetic and higher adsorption capacity for MO than GO. Moreover, PEI-GO had a good adsorption capacity in the acidic range, and the highest adsorption of MO occurred at pH=6.0. The adsorption of MO on PEI-GO was an endothermic, spontaneous and physisorption process.

  19. Supramolecular Nanostructures Based on Cyclodextrin and Poly(ethylene oxide: Syntheses, Structural Characterizations and Applications for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Yue Zheng

    2016-05-01

    Full Text Available Cyclodextrins (CDs have been extensively studied as drug delivery carriers through host–guest interactions. CD-based poly(pseudorotaxanes, which are composed of one or more CD rings threading on the polymer chain with or without bulky groups (or stoppers, have attracted great interest in the development of supramolecular biomaterials. Poly(ethylene oxide (PEO is a water-soluble, biocompatible polymer. Depending on the molecular weight, PEO can be used as a plasticizer or as a toughening agent. Moreover, the hydrogels of PEO are also extensively studied because of their outstanding characteristics in biological drug delivery systems. These biomaterials based on CD and PEO for controlled drug delivery have received increasing attention in recent years. In this review, we summarize the recent progress in supramolecular architectures, focusing on poly(pseudorotaxanes, vesicles and supramolecular hydrogels based on CDs and PEO for drug delivery. Particular focus will be devoted to the structures and properties of supramolecular copolymers based on these materials as well as their use for the design and synthesis of supramolecular hydrogels. Moreover, the various applications of drug delivery techniques such as drug absorption, controlled release and drug targeting based CD/PEO supramolecular complexes, are also discussed.

  20. Complex Formation Between Lysozyme and Stabilized Micelles with a Mixed Poly(ethylene oxide)/Poly(acrylic acid) Shell.

    Science.gov (United States)

    Karayianni, Maria; Gancheva, Valeria; Pispas, Stergios; Petrov, Petar

    2016-03-10

    The electrostatic complexation between lysozyme and stabilized polymeric micelles (SPMs) with a poly(acrylic acid) (PAA) or a mixed poly(ethylene oxide)/poly(acrylic acid) (PEO/PAA) shell (SPMs with a mixed shell, SPMMS) and a temperature-responsive poly(propylene oxide) (PPO) core was investigated by means of dynamic, static, and electrophoretic light scattering. The SPMs and different types of SPMMS used resulted from the self-assembly of PAA-PPO-PAA triblock copolymer chains, or PAA-PPO-PAA and PEO-PPO-PEO triblock copolymer chain mixtures (with varying chain lengths and molar ratios) in aqueous solutions at pH 10 and the subsequent cross-linking of their PPO cores via loading and photo-cross-linking of pentaerythritol tetraacrylate (PETA). The solution behavior, structure and properties of the formed complexes at pH 7 and 0.01 M ionic strength, were studied as a function of the protein concentration in the solution (the concentration of the stabilized micelles was kept constant) or equivalently the ratio of the two components. The complexation process and properties of the complexes proved to be dependent on the protein concentration, while of particular interest was the effect of the structure of the shell of the SPMs on the stability/solubility of the complexes. Finally, the fluorescence and mid infrared spectroscopic investigation of the structure of the complexed protein showed that, although a small stretching of the protein molecules occurred in some cases, no protein denaturation takes place upon complexation.

  1. Quantifying the effects of sterilization and aging on the oxidative degradation and wear of crosslinked and conventional polyethylene used in total joint replacement

    Science.gov (United States)

    Willie, Bettina Maria

    2005-07-01

    Nearly 500,000 total knee and hip replacements are performed annually in the United States. The generation of ultra-high molecular weight polyethylene (PE) particulate wear debris and associated osteolysis has increasingly become the predominant cause of revision operation. Research has shown that radiation sterilization in air results in increased oxidative degradation and accelerated wear of PE components. The overall goal of this work was to better understand the effect of sterilization, radiation crosslinking, and aging on the oxidative degradation and wear performance of PE components in order to improve clinical outcomes in total joint replacement. The data indicated that after four years of real-time shelf aging, PE that was radiation sterilized in air or nitrogen had significantly greater oxidative degradation compared to PE that was sterilized with either gas plasma or ethylene oxide. After two years of real-time shelf aging, negligible oxidation occurred with minimal changes in density and percent crystallinity, indicating that oxidative degradation was not an issue in the highly crosslinked and conventional polyethylene components examined. The differences measured between time zero and two years shelf aging may be likely explained by instrumentation error or variation within polyethylene manufacturing lots. Data suggest that current manufacturing and packaging technologies have successfully avoided oxidative degradation during shelf aging. Shelf aging may not be a concern in highly crosslinked or conventional polyethylene with current packaging technologies. Conventional PE tibial components had significantly greater percent area of premelt total surface damage compared to crosslinked PE tibial components. However, conventional PE tibial components did not have a significantly different percent area of postmelt total surface damage compared to crosslinked PE tibial components. Data indicated that in vivo duration was a significant predictor of premelt

  2. Electrochromic properties of inkjet printed vanadium oxide gel on flexible polyethylene terephthalate/indium tin oxide electrodes.

    Science.gov (United States)

    Costa, Cláudia; Pinheiro, Carlos; Henriques, Inês; Laia, César A T

    2012-10-24

    Vanadium oxide gel was synthesized and formulated for the assembly of solid-state electrochromic cells on flexible and transparent electrodes using inkjet printing. FTIR, Raman, and X-ray diffraction spectroscopic measurements showed that the vanadium oxide gel here synthesized consisted of V(2)O(5)·6H(2)O, microstructures similar to orthorhombic V(2)O(5), while Raman spectroscopy also shows the presence of amorphous domains. Atomic force microscopy (AFM) images of the thin films printed using an inkjet shows a ribbonlike structure, which is in accordance with previous results of the vanadium oxide gels in solution. Solid-state electrochromic devices were assembled at room temperature using the inkjet printed films, without any sinterization step. The electrochemical properties of the vanadium oxide gel were characterized by cyclic voltammetry and spectroelectrochemistry by visible/NIR absorption spectroscopy (in both liquid and solid-state). Several redox steps are observed, which gives rise to a variety of color transitions as a function of the applied voltage. The different optical properties of the vanadium oxide gel are assigned to different intercalation steps of Li(+), leading to different crystalline phases of the gel. The final result is a solid-state electrochromic cell showing excellent contrast between the redox states, giving rise to colors such as yellow, green, or blue. Color space analysis was used to characterize the electrochromic transitions, and while absorption spectra showed rather long switching times (up to 100 s), in L*a*b* color space coordinates, the switching time is smaller than 30 s. These electrochromic cells also have an excellent cycling stability showing high reversibility and a cyclability up to more than 30,000 cycles with a degradation of 18%.

  3. Poly(ethylene glycol) conjugated nano-graphene oxide for photodynamic therapy

    Institute of Scientific and Technical Information of China (English)

    Pilger; FRANK

    2010-01-01

    A novel methoxy-poly(ethylene glycol) modified nano-graphene oxide(NGO-mPEG) was designed and synthesized as a photosensitizer(PS) carrier for photodynamic therapy of cancer.NGO with a size below 200 nm was prepared using a modified Hummers’ method.NGO was observed by AFM to exhibit a structure with single-layer graphene oxide sheets down to a few nanometers in height.Hydrophilic mPEG conjugation of NGO(NGO-mPEG) was found to enhance solubility in cell culture media.No apparent cytotoxicity of the NGO-mPEG was observed towards MCF-7 carcinoma cell line.Zinc phthalocyanine(ZnPc),a photosensitizer for photodynamic therapy,was loaded in the NGO-PEG through π-π stacking and hydrophobic interactions,with the drug loading efficiency up to 14 wt%.Hydrophobic ZnPc was internalized in MCF-7 cells,exhibiting a pronounced phototoxicity in the cells under Xe light irradiation.The results indicate a great potential of NGO-mPEG for photodynamic therapy of cancer.

  4. Synthesis and Surface Tension Properties of Polyethyleneimine—Polyethylene Oxide Block Copolymers

    Institute of Scientific and Technical Information of China (English)

    张剑; LONNIE,Bryant

    2003-01-01

    This peper describes the synthesis,surface tension and dispersancy properties of block copolymer nonionic surfactants comprised of polyethyleneimine(PEI) and polyethlene oxide(PEO) blocks of selected lengths.These block copolymers were prepared by a threestep synthetic sequence.Firstly,PEO glycol was converted to its dimethanesulphonylester (dimesyl) derivative by reacting with methanesulphonyl chloride.Then a tri-block polymer was preparaed by the ring-opening polymerization of 2-methly-2-oxazoline(MeOZO)with the dimesyl PEO derivative.Lastly,linear PEI blocks were obtained by subsequent hydrolysis and purification.1H NMR spectra confirmed the structures of the intermediate,final products and their purities(>99%).The utility of these block copolymers is described in terms of their surface tension and clay dispersancy measurements as a function of copolymer chain and block length.

  5. EFFECTS OF ω-ACRYLOYL POLY(ETHYLENE OXIDE) MACROMONOMER ON EMULSIFIER-FREE EMULSION COPOLYMERIZATION OF METHYL METHACRYLATE AND n-BUTYL ACRYLATE

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Well-defined nonionic hydrophilic ω-acryloyl poly(ethylene oxide) macromonomer (PEO-A) has been prepared by living anionic polymerization of ethylene oxide with diphenyl methyl potassium as the initiator and acryloyl chloride as the reaction terminating agent. The polymer was characterized by FTIR and SEC. The emulsifier-free emulsion polymerization of methyl methacrylate (MMA) and n-butyl acrylate (BA) containing various concentrations of PEO-A was studied. In all cases stable emulsion coplymerizations of MMA and BA were obtained. The stabilizing effect was found to be dependent on the molecular weight and the feed amount of the macromonomer.

  6. Degradation of polyethylene induced by plasma in oxidizing atmospheres; Degradacion de polietileno inducido por plasma en atmosferas oxidantes

    Energy Technology Data Exchange (ETDEWEB)

    Colin, E.; Olayo, M.G.; Cruz, G.J. [Facultad de Quimica, UAEM, Av. Tollocan y Colon, 50000 Toluca (Mexico)

    2002-07-01

    The garbage of polyethylene is not easily degradable in normal environmental conditions . The indiscriminate use of this polymer and the enormous quantity of garbage which is generated carries a damage to the environment due to its long life as waste. The objective of this work is to study the conditions in which can be carried out the degradation of polyethylene. A form of accelerating the degradation is exposing it to plasma with reactive atmospheres. In this work a study of surface modification of polyethylene by plasmas with discharges of direct current of oxygen and nitrogen is presented. (Author)

  7. Effect of peptide secondary structure on adsorption and adsorbed film properties on end-grafted polyethylene oxide layers.

    Science.gov (United States)

    Binazadeh, M; Zeng, H; Unsworth, L D

    2014-01-01

    Poly-l-lysine (PLL), in α-helix or β-sheet configuration, was used as a model peptide for investigating the effect of secondary structures on adsorption events to poly(ethylene oxide) (PEO) modified surfaces formed using θ solvents. Circular dichroism results showed that the secondary structure of PLL persisted upon adsorption to Au and PEO modified Au surfaces. Quartz crystal microbalance with dissipation (QCM-D) was used to characterize the chemisorbed PEO layer in different solvents (θ and good solvents), as well as the sequential adsorption of PLL in different secondary structures (α-helix or β-sheet). QCM-D results suggest that chemisorption of PEO 750 and 2000 from θ solutions led to brushes 3.8 ± 0.1 and 4.5 ± 0.1 nm thick with layer viscosities of 9.2 ± 0.8 and 4.8 ± 0.5 cP, respectively. The average number of H2O per ethylene oxides, while in θ solvent, was determined as ~0.9 and ~1.2 for the PEO 750 and 2000 layers, respectively. Upon immersion in good solvent (as used for PLL adsorption experiments), the number of H2O per ethylene oxides increased to ~1.5 and ~2.0 for PEO 750 and 2000 films, respectively. PLL adsorbed masses for α-helix and β-sheet on Au sensors was 231 ± 5 and 1087 ± 14 ng cm(-2), with layer viscosities of 2.3 ± 0.1 and 1.2 ± 0.1 cP, respectively; suggesting that the α-helix layer was more rigid, despite a smaller adsorbed mass, than that of β-sheet layers. The PEO 750 layer reduced PLL adsorbed amounts to ~10 and 12% of that on Au for α-helices and β-sheets respectively. The PLL adsorbed mass to PEO 2000 layers dropped to ~12% and 4% of that on Au, for α-helix and β-sheet respectively. No significant differences existed for the viscosities of adsorbed α-helix and β-sheet PLL on PEO surfaces. These results provide new insights into the fundamental understanding of the effects of secondary structures of peptides and proteins on their surface adsorption.

  8. Spontaneous crystallinity loss of drugs in the disordered regions of poly(ethylene oxide) in the presence of water.

    Science.gov (United States)

    Marsac, Patrick J; Romary, Daniel P; Shamblin, Sheri L; Baird, Jared A; Taylor, Lynne S

    2008-08-01

    The physical stability of active pharmaceutical ingredients (APIs) formulated in the crystalline state may be compromised in the presence of excipients. In the present study, it is shown that at high relative humidity, several model crystalline drugs compacted into a matrix of poly(ethylene oxide) (PEO) may dissolve into the disordered regions of the polymer. The purpose of this project is to identify both the physicochemical properties of the API and the polymer which may lead to such a transformation and the mechanism of transformation. Crystalline drugs and PEO were physically mixed, compressed into tablets, and stored in a dessicator at 94% RH. The physical state of the drug and the polymer were determined using Raman spectroscopy and X-ray powder diffraction. The solubility of each drug in PEG 400 was measured by ultraviolet spectroscopy, the thermal properties of each compound were measured using differential scanning calorimetry, and the amount of water sorbed into these systems from the vapor phase was determined by gravimetric analysis. A spontaneous loss of crystallinity was observed for many of the model drugs when stored at high relative humidity and in the presence of PEO. In the absence of PEO, no changes in the crystalline material were observed. However, the structure of PEO was dramatically altered when exposed to high relative humidity. Specifically, it was found that PEO undergoes a very slow deliquescence increasing the disordered fraction of the polymer which facilitates the "dissolution" of the crystalline drug into these disordered regions. The degree of transformation, estimated from Raman spectroscopy, was found to qualitatively correlate with the aqueous solubility of the compounds. It can be concluded that for the systems studied here, the phase stability of the polymer was compromised at high relative humidity and the polymer underwent deliquescence. The equilibrium phase of several of the crystalline drugs studied here was then altered

  9. The influence of guaifenesin and ketoprofen on the properties of hot-melt extruded polyethylene oxide films.

    Science.gov (United States)

    Crowley, Michael M; Fredersdorf, Anke; Schroeder, Britta; Kucera, Shawn; Prodduturi, Suneela; Repka, Michael A; McGinity, James W

    2004-08-01

    Films containing polyethylene oxide (PEO) and a model drug, either guaifenesin (GFN) or ketoprofen (KTP), were prepared by hot-melt extrusion. The thermal properties of the hot-melt extruded films were investigated using differential scanning calorimetry (DSC). Scanning electron microscopy (SEM) was used to examine the surface morphology of the films, and wide angle X-ray diffraction (XRD) was used to investigate the crystalline properties of the polymer, drugs and physical mixtures as well as the solid state structure of the films. The stability of the polymer was studied using gel permeation chromatography. The mechanical properties, including percent elongation and tensile strength of the films, were determined on an Instron according to American Society for Testing Materials (ASTM) procedures. The Hansen solubility parameter was calculated using the Hoftyzer or van Krevelen method to estimate the likelihood of drug--polymer miscibility. Both GFN and KTP were stable during the extrusion process. Melting points corresponding to the crystalline drugs were not observed in the films. Crystallization of GFN on the surface of the film was observed at all concentrations studied, however KTP crystallization did not occur until reaching the 15% level. Guaifenesin and ketoprofen were found to decrease drive load, increase PEO stability and plasticize the polymer during extrusion. The Hansen solubility parameters predicted miscibility between PEO and KTP and poor miscibility between PEO and GFN. The predictions of the solubility parameters were in agreement with the XRD and SEM results. The percent elongation decreased with increasing GFN concentrations and significantly increased with increasing levels of KTP. Both GFN and KTP decreased the tensile strength of the extruded film.

  10. Performance of polymer electrolyte based on chitosan blended with poly(ethylene oxide) for plasmonic dye-sensitized solar cell

    Science.gov (United States)

    Buraidah, M. H.; Teo, L. P.; Au Yong, C. M.; Shah, Shahan; Arof, A. K.

    2016-07-01

    Chitosan and poly(ethylene oxide) powders have been mixed in different weight ratios. To each mixture, a fixed amount of ammonium iodide has been added. All mixtures have been dissolved in 1% acetic acid solution to form polymer blend electrolyte films by the solution cast technique. X-ray diffraction indicates that the polymer blend electrolytes are amorphous. Fourier transform infrared spectroscopy shows shifting of the amine, carboxamide and Csbnd Osbnd C bands to lower wavenumbers indicating the occurrence of complexation. Electrochemical impedance spectroscopy has been used to study the electrical properties of the samples. The ionic conductivity for 55 wt.% chitosan-45 wt.% NH4I electrolyte system is 3.73 × 10-7 S cm-1 at room temperature and is increased to 3.66 × 10-6 S cm-1 for the blended film (16.5 wt.% chitosan-38.5 wt.% PEO)-45 wt.% NH4I film. Dye-sensitized solar cells (DSSCs) have been fabricated by sandwiching the polymer electrolyte between the TiO2/dye photoelectrode and Pt counter electrode. DSSCs fabricated exhibits short-circuit current density (Jsc) of 2.71 mA cm-2, open circuit voltage (Voc) of 0.58 V and efficiency of 0.78% with configuration ITO/TiO2/N3 dye/(16.5 wt.% chitosan-38.5 wt.% PEO)-45 wt.% NH4I(+I2)/Pt/ITO and Jsc of 2.84 mA cm-2, Voc of 0.58 V and efficiency of 1.13% with configuration ITO/TiO2 + Ag nanoparticles/N3 dye/(16.5 wt.% chitosan-38.5 wt.% PEO)-45 wt.% NH4I(+I2)/Pt/ITO.

  11. Unusual phase separation and rheological behavior of poly(ethylene oxide)/ionic liquid mixtures with specific interactions.

    Science.gov (United States)

    Xiao, Zhilin; Larson, Ronald G; Chen, Yunlei; Zhou, Chenting; Niu, Yanhua; Li, Guangxian

    2016-09-28

    The phase separation behavior of poly(ethylene oxide) (PEO) in ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF4]) was investigated by rheological, optical microscopy, FT-IR and DSC measurements. It is demonstrated that specific interactions, particularly the hydrogen bonding between PEO and the ionic liquids as evidenced by FT-IR, in which a subtle but apparent absorption peak shift near the phase transition appears, account for the unusual low critical solution temperature (LCST) phase separation. Unlike the typical trend in which the storage modulus G' simply increases with temperature near the phase boundary for polymer blends without specific interaction, in our study, a novel "V-shaped" rheological response is observed, namely a dip in G' followed by an upturn, especially at low PEO concentration (<50 wt%). The magnitude of the "V" dip has heating rate and frequency dependences, while Tr (the phase transition temperature) is almost unchanged with heating rate and frequency. Upon increasing the alkyl chain length on the imidazolium ring from an ethyl to a butyl, the "V-shape" becomes more prominent and shifts to higher temperature, which is consistent with the results of FT-IR and DSC, evidently due to the stronger hydrogen bonding interaction between PEO and [BMIM][BF4] than [EMIM][BF4]. This unusual "V" dip might be tentatively ascribed to the coupling effects of the breaking of the "hydrogen bonding cage" formed between PEO chains and IL molecules and dissolution of the heterogeneous clusters as verified by FT-IR and TEM, respectively, and the following upturn is dominated by the interface formation upon phase separation.

  12. Structural effect of glyme-Li(+) salt solvate ionic liquids on the conformation of poly(ethylene oxide).

    Science.gov (United States)

    Chen, Zhengfei; McDonald, Samila; Fitzgerald, Paul A; Warr, Gregory G; Atkin, Rob

    2016-06-01

    The conformation of 36 kDa polyethylene oxide (PEO) dissolved in three glyme-Li(+) solvate ionic liquids (SILs) has been investigated by small angle neutron scattering (SANS) and rheology as a function of concentration and compared to a previously studied SIL. The solvent quality of a SIL for PEO can be tuned by changing the glyme length and anion type. Thermogravimetric analysis (TGA) reveals that PEO is dissolved in the SILs through Li(+)-PEO coordinate bonds. All SILs (lithium triglyme bis(trifluoromethanesulfonyl)imide ([Li(G3)]TFSI), lithium tetraglyme bis(pentafluoroethanesulfonyl)imide ([Li(G4)]BETI), lithium tetraglyme perchlorate ([Li(G4)]ClO4) and the recently published [Li(G4)]TFSI) are found to be moderately good solvents for PEO but solvent quality decreases in the order [Li(G4)]TFSI ∼ [Li(G4)]BETI > [Li(G4)]ClO4 > [Li(G3)]TFSI due to decreased availability of Li(+) for PEO coordination. For the same glyme length, the solvent qualities of SILs with TFSI(-) and BETI(-) anions ([Li(G4)]TFSI and [Li(G4)]BETI) are very similar because they weakly coordinate with Li(+), which facilitates Li(+)-PEO interactions. [Li(G4)]ClO4 presents a poorer solvent environment for PEO than [Li(G4)]BETI because ClO4(-) binds more strongly to Li(+) and thereby hinders interactions with PEO. [Li(G3)]TFSI is the poorest PEO solvent of these SILs because G3 binds more strongly to Li(+) than G4. Rheological and radius of gyration (Rg) data as a function of PEO concentration show that the PEO overlap concentrations, c* and c**, are similar in the three SILs.

  13. Stability of silicon and titanium carbide suspensions in electrolyte, poly(ethylene oxide), and PEO-surfactant solutions.

    Science.gov (United States)

    Barany, Sandor; Eremenko, Boris V; Malysheva, Mariya L

    2004-07-01

    It has been shown that the coagulation values of counterions for SiC and TiC suspensions with particle radius from 0.5 to 5 microm obey a z(2.5-3.5) law and there is an insufficient change in the critical concentration of 1-1 electrolytes (CCE) when the surface potential of particles increases more than two times. Also, the CCE values hardly depend on the position of counterions in the lyotropic sequence. This is explained by aggregation of SiC and TiC particles at a secondary minimum, which is proved by calculations of the potential curves of interparticle interactions using the DLVO theory. The adsorption of poly(ethylene oxide) on the surfaces studied does not cause--in contradiction to dispersions with smaller particles--an unlimited growth in the stability of suspensions. This is due to the aggregation of large particles with adsorbed PEO, as in polymer-free dispersions, under barrierless conditions in which the coordinates of the secondary minimum are determined by superposition of molecular attractive forces and steric repulsive forces of adsorbed polymeric chains, without a contribution from the electric repulsion term. PEO-anionic surfactant complexes possess higher stabilizing capacity compared to the individual components of the mixture. Our results show that the adsorbed polymer layers may hinder the aggregation both in the primary and in the secondary minimum for not very large particles only, the critical size of which depends on the dispersed phase nature and the molecular mass of the polymer.

  14. Colloidal crystals of core-shell type spheres with poly(styrene) core and poly(ethylene oxide) shell.

    Science.gov (United States)

    Okamoto, Junichi; Kimura, Hiroshi; Tsuchida, Akira; Okubo, Tsuneo; Ito, Koichi

    2007-04-15

    Elastic modulus and crystal growth kinetics have been studied for colloidal crystals of core-shell type colloidal spheres (diameter=160-200 nm) in aqueous suspension. Crystallization properties of three kinds of spheres, which have poly(styrene) core and poly(ethylene oxide) shell with different oxyethylene chain length (n=50, 80 and 150), were examined by reflection spectroscopy. The suspensions were deionized exhaustively for more than 1 year using mixed bed of ion-exchange resins. The rigidities of the crystals range from 0.11 to 120 Pa and from 0.56 to 76 Pa for the spheres of n=50 and 80, respectively, and increase sharply as the sphere volume fraction increase. The g factor, parameter for crystal stability, range from 0.029 to 0.13 and from 0.040 to 0.11 for the spheres of n=50 and 80, respectively. These g values indicate the formation of stable crystals, and the values were decreased as the sphere volume fraction increased. Two components of crystal growth rate coefficients, fast and slow, were observed in the order from 10(-3) to 10(1)s(-1). This is due to the secondary process in the colloidal crystallization mechanism, corresponding to reorientation from metastable crystals formed in the primary process and/or Ostwald-ripening process. There are no distinct differences in the structural, kinetic and elastic properties among the colloidal crystals of the different core-shell size spheres, nor difference between those of core-shell spheres and silica or poly(styrene) spheres. The results are very reasonably interpreted by the fact that colloidal crystals are formed in a closed container owing to long-range repulsive forces and the Brownian movement of colloidal spheres surrounded by extended electrical double layers, and their formation is not influenced by the rigidity and internal structure of the spheres.

  15. Highly flexible, transparent, and low resistance indium zinc oxide-Ag-indium zinc oxide multilayer anode on polyethylene terephthalate substrate for flexible organic light light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Sung-Woo; Jeong, Jin-A; Bae, Jung-Hyeok; Moon, Jong-Min; Choi, Kwang-Hyuk; Jeong, Soon Wook; Park, No-Jin [School of Advanced Materials and Systems Engineering, Kumoh National Institute of Technology (KIT), Gumi 730-701 (Korea, Republic of); Kim, Jang-Joo; Lee, Se Hyung [School of Materials Science and Engineering, Seoul National University and Organic Light Emitting Diodes Center, Sillim-dong, Seoul 151-741 (Korea, Republic of); Kang, Jae-Wook [Surface Technology Research Center, Korea Institute of Machinery and Materials, 66 Sangnam-dong, Changwon-si, Gyeongnam, 641-831 (Korea, Republic of); Yi, Min-Su [Department of Materials Science and Engineering, Kyungpook National University, Sangju, Gyeongbuk, 742-711 (Korea, Republic of); Kim, Han-Ki [School of Advanced Materials and Systems Engineering, Kumoh National Institute of Technology (KIT), Gumi 730-701 (Korea, Republic of)], E-mail: hkkim@kumoh.ac.kr

    2008-09-01

    The characteristics of indium zinc oxide (IZO)-Ag-IZO multilayer grown on a polyethylene terephthalate (PET) substrate were investigated for flexible organic light-emitting diodes (OLEDs). The IZO-Ag-IZO (IAI) multilayer anode exhibited a remarkably reduced sheet resistance of 6.93 {omega}/{open_square} and a high transmittance of 84.8%, despite the very thin thickness of the IZO (30 nm) layer. In addition, it was shown that electrical and optical properties of IAI anodes are critically dependent on the thickness of the Ag layer, due to the transition of Ag atoms from distinct islands to continuous films at a critical thickness (12 nm). Moreover, the IAI/PET sample showed more stable mechanical properties than an amorphous ITO/PET sample during the bending test due to the existence of a ductile Ag layer. The current density-voltage-luminance characteristics of flexible OLEDs fabricated on an IAI/PET substrate was better than those of flexible OLEDs fabricated on an ITO/PET substrate. This indicates that IAI multilayer anodes are promising flexible and transparent electrodes for flexible OLEDs.

  16. Lactosylated poly(ethylene oxide)-poly(propylene oxide) block copolymers for potential active targeting: synthesis and physicochemical and self-aggregation characterization

    Energy Technology Data Exchange (ETDEWEB)

    Cuestas, Maria L.; Glisoni, Romina J. [University of Buenos Aires, Group of Biomaterials and Nanotechnology for Improved Medicines (BIONIMED), Department of Pharmaceutical Technology, Faculty of Pharmacy and Biochemistry (Argentina); Mathet, Veronica L. [National Science Research Council (CONICET) (Argentina); Sosnik, Alejandro, E-mail: alesosnik@gmail.com [University of Buenos Aires, The Group of Biomaterials and Nanotechnology for Improved Medicines (BIONIMED), Department of Pharmaceutical Technology, Faculty of Pharmacy and Biochemistry (Argentina)

    2013-01-15

    Aiming to develop polymeric self-assembly nanocarriers with potential applications in active drug targeting to the liver, linear and branched poly(ethylene oxide)-poly(propylene oxide) amphiphiles were conjugated to lactobionic acid (LA), a disaccharide of galactose and gluconic acid, by the conventional Steglich esterification reaction. The conjugation was confirmed by ATR/FT-IR, {sup 1}H-NMR, and {sup 13}C-NMR spectroscopy. Elemental analysis and MALDI-TOF mass spectrometry were employed to elucidate the conjugation extent and the final molecular weight, respectively. The critical micellar concentration (CMC), the size and size distribution and zeta potential of the pristine and modified polymeric micelles under different conditions of pH and temperature were characterized by dynamic light scattering (DLS). Conjugation with LA favored the micellization process, leading to a decrease of the CMC with respect to the pristine counterpart, this phenomenon being independent of the pH and the temperature. At 37 Degree-Sign C, micelles made of pristine copolymers showed a monomodal size distribution between 12.8 and 24.4 nm. Conversely, LA-conjugated micelles showed a bimodal size pattern that comprised a main fraction of relatively small size (11.6-22.2 nm) and a second one with remarkably larger sizes of up to 941.4 nm. The former corresponded to single micelles, while the latter would indicate a secondary aggregation phenomenon. The spherical morphology of LA-micelles was visualized by transmission electron microscopy (TEM). Finally, to assess the ability of the LA-conjugated micelles to interact with lectin-like receptors, samples were incubated with concanavalin A at 37 Degree-Sign C and the size and size distribution were monitored by DLS. Findings indicated that regardless of the relatively weak affinity of this vegetal lectin for galactose, micelles underwent agglutination probably through the interaction of a secondary site in the lectin with the gluconic acid

  17. Poly(ethylene oxide/propylene oxide) copolymer thermo-reversible gelling system for the enhancement of intranasal zidovudine delivery to the brain.

    Science.gov (United States)

    Ved, Parag M; Kim, Kwonho

    2011-06-15

    The purpose of this study was to investigate the olfactory transfer of zidovudine (ZDV) after intranasal (IN) administration and to assess the effect of thermoreversible gelling system on its absorption and brain uptake. The nasal formulation was prepared by dissolving ZDV in pH 5.5 phosphate buffer solution comprising of 20% polyethylene oxide/propylene oxide (Poloxamer 407, PLX) as thermoreversible gelling agent and 0.1% n-tridecyl-β-D-maltoside (TDM) as permeation enhancer. This formulation exhibited a sufficient stability and an optimum gelation profile at 27-30 °C. The in vitro permeation studies across the freshly excised rabbit nasal mucosa showed a 53% increase in the permeability of ZDV from the formulation. For in vivo evaluation, the drug concentrations in the plasma, cerebrospinal fluid (CSF) and six different regions of the brain tissues, i.e. olfactory bulb (OB), olfactory tract (OT), anterior, middle and posterior segments of cerebrum (CB), and cerebellum (CL) were determined by LC/MS method following IV and IN administration in rabbits at a dose of 1mg/kg. The IN administration of Poloxamer 407 and TDM based formulation showed a systemic bioavailability of 29.4% while exhibiting a 4 times slower absorption process (t(max) = 20 min) than control solution (t(max) = 5 min). The CSF and brain ZDV levels achieved after IN administration of the gelling formulation were approximately 4.7-56 times greater than those attained after IV injection. The pharmacokinetic and brain distribution studies revealed that a polar antiviral compound, ZDV could preferentially transfer into the CSF and brain tissue via an alternative pathway, possibly olfactory route after intranasal administration.

  18. Pyrolysis result of polyethylene waste as fuel for solid oxide fuel cell with samarium doped-ceria (SDC)-carbonate as electrolyte

    Science.gov (United States)

    Syahputra, R. J. E.; Rahmawati, F.; Prameswari, A. P.; Saktian, R.

    2017-02-01

    In this research, the result of pyrolysis on polyethylene was used as fuel for a solid oxide fuel cell (SOFC). The pyrolysis result is a liquid which consists of hydrocarbon chains. According to GC-MS analysis, the hydrocarbons mainly consist of C7 to C20 hydrocarbon chain. Then, the liquid was applied to a single cell of NSDC-L | NSDC | NSDC-L. NSDC is a composite SDC (samarium doped-ceria) with sodium carbonate. Meanwhile, NSDC-L is a composite of NSDC with LiNiCuO (LNC). NSDC and LNC were analyzed by X-ray diffraction to understand their crystal structure. The result shows that presence of carbonate did not change the crystal structure of SDC. SEM EDX analysis for fuel cell before and after being loaded with polyethylene oil to get information of element diffusion to the electrolyte. Meanwhile, the conductivity properties were investigated through impedance measurement. The presence of carbonate even increases the electrical conductivity. The single cell test with the pyrolysis result of polyethylene at 300 – 600 °C, found that the highest power density is at 600 °C with the maximum power density of 0.14 mW/cm2 and open circuit voltage of 0.4 Volt. Elemental analysis at three point spots of single cell NDSC-L |NSDC|NSDC-L found that a migration of ions was occurred during fuel operation at 300 – 600 °C.

  19. Improvement of the thermal and thermo-oxidative stability of high-density polyethylene by free radical trapping of rare earth compound

    Energy Technology Data Exchange (ETDEWEB)

    Ran, Shiya; Zhao, Li; Han, Ligang [Laboratory of Polymer Materials and Engineering, Ningbo Institute of Technology, ZhejiangUniversity, Ningbo, 315100 (China); MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Institute of Polymer Composites, Zhejiang University, Hangzhou, 310027 (China); Guo, Zhenghong, E-mail: guozhenghong@nit.zju.edu.cn [Laboratory of Polymer Materials and Engineering, Ningbo Institute of Technology, ZhejiangUniversity, Ningbo, 315100 (China); Fang, Zhengping [Laboratory of Polymer Materials and Engineering, Ningbo Institute of Technology, ZhejiangUniversity, Ningbo, 315100 (China); MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Institute of Polymer Composites, Zhejiang University, Hangzhou, 310027 (China)

    2015-07-20

    Highlights: • Polyethylene filled with ytterbium trifluoromethanesulfonate was prepared. • A low Yb loading improved thermal stability of PE obviously by radical trapping. • Yb(OTf){sub 3} is expected to be an efficient thermal stabilizer for the polymer. - Abstract: A kind of rare earth compound, ytterbium trifluoromethanesulfonate (Yb(OTf){sub 3}), was introduced into high-density polyethylene (HDPE) by melt compounding to investigate the effect of Yb(OTf){sub 3} on the thermal and thermo-oxidative stability of HDPE. The results of thermogravimetric (TG) and differential scanning calorimetry (DSC) showed that the addition of Yb(OTf){sub 3} made the thermal degradation temperatures dramatically increased, the oxidative induction time (OIT) extended, and the enthalpy (ΔH{sub d}) reduced. Very low Yb(OTf){sub 3} loading (0.5 wt%) in HDPE could increase the onset degradation temperature in air from 334 to 407 °C, delay the OIT from 11.0 to 24.3 min, and decrease the ΔH{sub d} from 61.0 to 13.0 J/g remarkably. Electron spin resonance spectra (ESR), thermogravimetric analysis coupled to Fourier transform infrared spectroscopy (TGA-FTIR), rheological investigation and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) indicated that the free radicals-trapping ability of Yb(OTf){sub 3} was responsible for the improved thermal and thermo-oxidative stability.

  20. 氧化石墨纳米薄片表面接枝聚乙二醇%Graphite Oxide Nanoplatelets Surface Graft Polyethylene Glycol

    Institute of Scientific and Technical Information of China (English)

    张磊; 唐建国; 刘海燕

    2009-01-01

    利用甲苯二异氰酸酯(TDI)作为连接剂,将聚乙二醇接枝在氧化石墨纳米薄片(GONPs)表面.氧化石墨选用改良的Hummers方法制备, 并用过量的TDI进行化学改性.经过改性后的氧化石墨在无水二甲基甲酰胺中剥离形成氧化石墨纳米薄片,随后在氮气保护下接枝上聚乙二醇.用X-射线衍射、傅里叶红外及元素分析对产物进行研究表征.%Polyethylene glycol (PEG) was grafted onto the graphite oxide nanoplatelets (GONPs) surface successfully using toluene diisocyanate (TDI) as coupling agent. The graphite oxide is synthesized by graphite oxide is exfoliated into two-dimensional GONPs in anhydrous N, N-dimethylformamide and grafted polyethylene glycol under nitrogen atmosphere. The product is characterized by X-ray diffraction, FT-infrared analysis and elemental analysis.

  1. Release of Bacteriocins from Nanofibers Prepared with Combinations of Poly(D,L-lactide (PDLLA and Poly(Ethylene Oxide (PEO

    Directory of Open Access Journals (Sweden)

    Leon Dicks

    2011-03-01

    Full Text Available Plantaricin 423, produced by Lactobacillus plantarum, and bacteriocin ST4SA produced by Enterococcus mundtii, were electrospun into nanofibers prepared from different combinations of poly(D,L-lactide (PDLLA and poly(ethylene oxide (PEO dissolved in N,N-dimethylformamide (DMF. Both peptides were released from the nanofibers with a high initial burst and retained 88% of their original antimicrobial activity at 37 °C. Nanofibers have the potential to serve as carrier matrix for bacteriocins and open a new field in developing controlled antimicrobial delivery systems for various applications.

  2. Release of bacteriocins from nanofibers prepared with combinations of poly(d,l-lactide) (PDLLA) and poly(ethylene oxide) (PEO).

    Science.gov (United States)

    Heunis, Tiaan; Bshena, Osama; Klumperman, Bert; Dicks, Leon

    2011-01-01

    Plantaricin 423, produced by Lactobacillus plantarum, and bacteriocin ST4SA produced by Enterococcus mundtii, were electrospun into nanofibers prepared from different combinations of poly(d,l-lactide) (PDLLA) and poly(ethylene oxide) (PEO) dissolved in N,N-dimethylformamide (DMF). Both peptides were released from the nanofibers with a high initial burst and retained 88% of their original antimicrobial activity at 37 °C. Nanofibers have the potential to serve as carrier matrix for bacteriocins and open a new field in developing controlled antimicrobial delivery systems for various applications.

  3. Dispersion fraction enhances cellular growth of carbon nanotube and aluminum oxide reinforced ultrahigh molecular weight polyethylene biocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Anup Kumar; Balani, Kantesh, E-mail: kbalani@iitk.ac.in

    2015-01-01

    Ultrahigh molecular weight polyethylene (UHMWPE) is widely used as bone-replacement material for articulating surfaces due to its excellent wear resistance and low coefficient of friction. But, the wear debris, generated during abrasion between mating surfaces, leads to aseptic loosening of implants. Thus, various reinforcing agents are generally utilized, which may alter the surface and biological properties of UHMWPE. In the current work, the cellular response of compression molded UHMWPE upon reinforcement of bioactive multiwalled carbon nanotubes (MWCNTs) and bioinert aluminum oxide (Al{sub 2}O{sub 3}) is investigated. The phase retention and stability were observed using X-ray diffraction, Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The reinforcement of MWCNTs and Al{sub 2}O{sub 3} has shown to alter the wettability (from contact angle of ∼ 88° ± 2° to ∼ 118° ± 4°) and surface energy (from ∼ 23.20 to ∼ 17.75 mN/m) of composites with respect to UHMWPE, without eliciting any adverse effect on cytocompatibility for the L929 mouse fibroblast cell line. Interestingly, the cellular growth of the L929 mouse fibroblast cell line is observed to be dominated by the dispersion fraction of surface free energy (SFE). After 48 h of incubation period, a decrease in metabolic activity of MWCNT–Al{sub 2}O{sub 3} reinforced composites is attributed to apatite formation that reduces the dispersion fraction of surface energy. The mineralized apatite during incubation was confirmed and quantified by energy dispersive spectroscopy and X-ray diffraction respectively. Thus, the dispersion fraction of surface free energy can be engineered to play an important role in achieving enhanced metabolic activity of the MWCNT–Al{sub 2}O{sub 3} reinforced UHMWPE biopolymer composites. - Highlights: • The cellular response of UHMWPE upon MWCNT and Al{sub 2}O{sub 3} reinforcement is highlighted. • Wettability decreases with Al{sub 2}O{sub 3} and

  4. Nitric oxide and prostaglandin E2 production in response to ultra-high molecular weight polyethylene particles depends on osteoblast maturation state.

    Science.gov (United States)

    Lohmann, Christoph H; Dean, David D; Bonewald, Lynda F; Schwartz, Zvi; Boyan, Barbara D

    2002-03-01

    Recent studies have shown that osteoblast-like cells respond directly to ultra-high molecular weight polyethylene particles in culture, suggesting that they may be involved in aseptic loosening of endoprostheses. We tested the hypothesis that the state of cell maturation plays a role in the response of osteogenic cells to ultra-high molecular weight polyethylene particles. MG63 cells (immature osteoblast-like cells), OCT-1 cells (mature secretory osteoblast-like cells), and MLO-Y4 cells (osteocyte-like cells) were treated for twenty-four hours with commercial ultra-high molecular weight polyethylene particles with an average diameter of 1 mm. The effect of particle treatment on cell proliferation was assessed by measuring the number of cells, whereas the effects on differentiation and local factor production were assessed by measuring the production of osteocalcin, prostaglandin E2, and nitric oxide. The effect of particles on apoptosis was also evaluated. The addition of ultra-high molecular weight polyethylene particles increased the number of MG63 cells, did not affect the number of OCT-1 cells, and led to a decrease in the number of MLO-Y4 cells. The observed changes in cell number were not due to programmed cell death, as no more than 3% of the cells in cultures treated with the highest concentration of particles were undergoing apoptosis. Osteocalcin production was not affected by the addition of particles. Prostaglandin E2 production was increased in all three types of cultures, but the effect was greatest in OCT-1 cell cultures, as was the absolute amount of prostaglandin E2 produced. Nitric oxide production was unaffected in MG63 cell cultures, but it was stimulated in OCT-1 and MLO-Y4 cell cultures. The results of the present study support the hypothesis that osteoblast cell maturation state plays an important role in the response to ultra-high molecular weight polyethylene particles and that the terminally differentiated osteocyte may be involved in the

  5. Poly(ethylene oxide)-co-poly(propylene oxide)-based gel electrolyte with high ionic conductivity and mechanical integrity for lithium-ion batteries.

    Science.gov (United States)

    Wang, Shih-Hong; Hou, Sheng-Shu; Kuo, Ping-Lin; Teng, Hsisheng

    2013-09-11

    Using gel polymer electrolytes (GPEs) for lithium-ion batteries usually encounters the drawback of poor mechanical integrity of the GPEs. This study demonstrates the outstanding performance of a GPE consisting of a commercial membrane (Celgard) incorporated with a poly(ethylene oxide)-co-poly(propylene oxide) copolymer (P(EO-co-PO)) swelled by a liquid electrolyte (LE) of 1 M LiPF6 in carbonate solvents. The proposed GPE stably holds LE with an amount that is three times that of the Celgard-P(EO-co-PO) composite. This GPE has a higher ionic conductivity (2.8×10(-3) and 5.1×10(-4) S cm(-1) at 30 and -20 °C, respectively) and a wider electrochemical voltage range (5.1 V) than the LE-swelled Celgard because of the strong ion-solvation power of P(EO-co-PO). The active ion-solvation role of P(EO-co-PO) also suppresses the formation of the solid-electrolyte interphase layer. When assembling the GPE in a Li/LiFePO4 battery, the P(EO-co-PO) network hinders anionic transport, producing a high Li+ transference number of 0.5 and decreased the polarization overpotential. The Li/GPE/LiFePO4 battery delivers a discharge capacity of 156-135 mAh g(-1) between 0.1 and 1 C-rates, which is approximately 5% higher than that of the Li/LE/LiFePO4 battery. The IR drop of the Li/GPE/LiFePO4 battery was 44% smaller than that of the Li/LE/LiFePO4. The Li/GPE/LiFePO4 battery is more stable, with only a 1.2% capacity decay for 150 galvanostatic charge-discharge cycles. The advantages of the proposed GPE are its high stability, conductivity, Li+ transference number, and mechanical integrity, which allow for the assembly of GPE-based batteries readily scalable to industrial levels.

  6. Aqueous laponite clay dispersions in the presence of poly(ethylene oxide) or poly(propylene oxide) oligomers and their triblock copolymers.

    Science.gov (United States)

    De Lisi, R; Gradzielski, M; Lazzara, G; Milioto, S; Muratore, N; Prévost, S

    2008-08-07

    The effect of polyethylene oxide (PEO) or polypropylene oxide (PPO) oligomers of various molecular weight (Mw) as well as of triblock copolymers, based on PEO and PPO blocks, on aqueous laponite RD suspensions was studied with small-angle neutron scattering (SANS). The radius of gyration (RG) increases for low M w whereas the opposite occurs for larger Mw. This behavior is explained on the basis that an effective R G is given by two contributions: (1) the size of the particles coated with the polymer and (2) the interactions between the laponite RD particles which are attractive for small and repulsive for large polymers. The SANS curves in the whole Q-range are well described by a model of noninteracting polydisperse core+shell disks, where the thickness of the polymer layer increases with the Mw. The adsorbed polymer is in a more compact conformation compared to a random coil distribution while the fraction of the polymer in the shell formed around the laponite RD particles is nearly independent of Mw. For increasing laponite RD amounts, at a given polymer composition, the thickness of the polymer slightly changes. In some cases, where also gelation is sped up, a structure factor with attractive interaction was employed which allowed to evaluate the attractive forces between the laponite RD particles. The gelation time was determined for mixtures at fixed copolymer and laponite RD concentrations. Surprisingly, it is observed that gels are formed despite the fact that the binding sites of the laponite RD particles are almost covered but the polymer size is too small to prevent aggregation. The gelation rate is correlated to structure and thermodynamics of these systems. Namely, when the balance between the steric forces and the depletion attractive forces undergoes an abrupt change the gelation time also undergoes a sharp variation. For lower and comparable Mw, PPO speeds up the gelation more efficiently than PEO while for higher Mw the gelation kinetics is slowed

  7. Poly(ethylene oxide)-silica hybrids entrapping sensitive dyes for biomedical optical pH sensors: Molecular dynamics and optical response

    Science.gov (United States)

    Fabbri, Paola; Pilati, Francesco; Rovati, Luigi; McKenzie, Ruel; Mijovic, Jovan

    2011-06-01

    Polymer-silica hybrid nanocomposites prepared by sol-gel process based on triethoxisilane-terminated poly(ethylene oxide) chains and tetraethoxysilane as silica precursor, doped with organic pH sensitive dyes, have been prepared and their suitability for use as sensors coupled with plastic optic fibers has been evaluated. Sensors were prepared by immobilizing a drop of the hybrid materials onto the tip of a multi-mode poly(methyl methacrylate) optical fiber. The performance of the optical sensor in terms of sensitivity and response time was tested in different experimental conditions, and was found to be markedly higher than analogous sensors present on the market. The very fast kinetic of the hybrid's optical response was supported by studies performed at the molecular level by broadband dielectric relaxation spectroscopy (DRS), investigated over a wide range of frequency and temperature, showing that poly(ethylene oxide) chains maintain their dynamics even when covalently bonded to silica domains, which decrease the self-association interactions and promote motions of polymer chain segments. Due to the fast response kinetic observed, these pH optical sensors result suitable for the fast-detection of biomedical parameters, i.e. fast esophageous pH-metry.

  8. Plasticizing effect of K+ ions and succinonitrile on electrical conductivity of [poly(ethylene oxide)-succinonitrile]/KI-I2 redox-couple solid polymer electrolyte.

    Science.gov (United States)

    Gupta, Ravindra Kumar; Rhee, Hee-Woo

    2013-06-20

    The plasticizing effect of the K(+) ions and succinonitrile on the electrical conductivity of a new redox-couple solid polymer electrolyte system, (1 - x)[0.5poly(ethylene oxide):0.5succinonitrile]:x[0.9KI:0.1I2] with x = 0-0.2 in weight fraction, is reported. An increase of x resulted in an increase of the electrical conductivity (σ25°C) of the electrolyte. The electrolyte with x = 0.15 exhibited the highest σ25°C value, ~7 × 10(-4) S cm(-1), and is referred to as the optimum conducting composition (OCC). In addition to an increase of the mobile ion concentration with increasing x, X-ray diffractometry, Fourier-transform infrared spectroscopy, polarized optical microscopy, UV-vis spectroscopy, and differential scanning calorimetry studies revealed a decrease of poly(ethylene oxide) crystallinity/an increase of ionic mobility, indicating the plasticizing effect of the K(+) ions. Plasticizing and molecular diffusing properties of the succinonitrile further helped to improve the electrical conductivity of the electrolyte.

  9. Recyclable magnetic nanocluster crosslinked with poly(ethylene oxide)-block-poly(2-vinyl-4,4-dimethylazlactone) copolymer for adsorption with antibody.

    Science.gov (United States)

    Prai-In, Yingrak; Boonthip, Chatchai; Rutnakornpituk, Boonjira; Wichai, Uthai; Montembault, Véronique; Pascual, Sagrario; Fontaine, Laurent; Rutnakornpituk, Metha

    2016-10-01

    Surface modification of magnetic nanoparticle (MNP) with poly(ethylene oxide)-block-poly(2-vinyl-4,4-dimethylazlactone) (PEO-b-PVDM) diblock copolymers and its application as recyclable magnetic nano-support for adsorption with antibody were reported herein. PEO-b-PVDM copolymers were first synthesized via a reversible addition-fragmentation chain-transfer (RAFT) polymerization using poly(ethylene oxide) chain-transfer agent as a macromolecular chain transfer agent to mediate the RAFT polymerization of VDM. They were then grafted on amino-functionalized MNP by coupling with some azlactone rings of the PVDM block to form magnetic nanoclusters with tunable cluster size. The nanocluster size could be tuned by adjusting the chain length of the PVDM block. The nanoclusters were successfully used as efficient and recyclable nano-supports for adsorption with anti-rabbit IgG antibody. They retained higher than 95% adsorption of the antibody during eight adsorption-separation-desorption cycles, indicating the potential feasibility in using this novel hybrid nanocluster as recyclable support in cell separation applications.

  10. Preparation of some thermal stable polymers based on diesters of polyethylene and polypropylene oxides macro monomers to use as surfactants at high temperature and pressure

    Directory of Open Access Journals (Sweden)

    A.M. Alsabagh

    2016-09-01

    Full Text Available Based on polyethylene (PE and polypropylene (PP oxides, six macromonomers were prepared through two steps. The first step was esterification of the PE and PP oxides, with oleic acid to give the corresponding monoesters. The second was the diesterfication of the prepared monoesters with methacrylic acid to give the corresponding diesters. The prepared macromonomers (diesters were polymerized to obtain six polymers. The chemical structure of the prepared mono- and diesters and polymers was justified by IR, NMR, GPC and TGA. The obtained results confirmed that the prepared polymers have a high thermal stability and can be used in high pressure and temperature during the drainage of the water from water-in-oil emulsions. The surface active and thermodynamics parameters of these polymers in non-aqueous solution were also investigated and it was found that, these materials have high thermal stability which leads to the possibility to be used under severe reservoir conditions as surfactants.

  11. Delayed hepatic uptake of multi-phosphonic acid poly(ethylene glycol) coated iron oxide measured by real-time Magnetic Resonance Imaging

    CERN Document Server

    Ramniceanu, G; Vezignol, C; Graillot, A; Loubat, C; Mignet, N; Berret, J -F

    2016-01-01

    We report on the synthesis, characterization, stability and pharmacokinetics of novel iron based contrast agents for magnetic resonance imaging (MRI). Statistical copolymers combining multiple phosphonic acid groups and poly(ethylene glycol) (PEG) were synthesized and used as coating agents for 10 nm iron oxide nanocrystals. In vitro, protein corona and stability assays show that phosphonic acid PEG copolymers outperform all other coating types examined, including low molecular weight anionic ligands and polymers. In vivo, the particle pharmacokinetics is investigated by monitoring the MRI signal intensity from mouse liver, spleen and arteries as a function of the time, between one minute and seven days after injection. Iron oxide particles coated with multi-phosphonic acid PEG polymers are shown to have a blood circulation lifetime of 250 minutes, i.e. 10 to 50 times greater than that of recently published PEGylated probes and benchmarks. The clearance from the liver takes in average 2 to 3 days and is indep...

  12. Well-defined 4-arm stars with hydroxy-terminated polyethylene, polyethylene-b-polycaprolactone and polyethylene-b-(polymethyl methacrylate) 2 arms

    KAUST Repository

    Zhang, Zhen

    2016-07-20

    Bis-boron-thexyl-silaboracycle was prepared by hydroboration of 1,4-bis(methyldivinylsilyl)butane with thexylborane and used to initiate the polyhomologation of dimethylsulfoxonium methylide to afford well-defined hydroxy-terminated 4-arm polyethylene (PE) stars. The synthesized PE stars were transformed to (PE-b-PCL)4 starblock copolymers via the ring-opening polymerization of ϵ-caprolactone (CL) initiated by the hydroxyl end groups of (PE-OH)4 in the presence of P2-tBu phosphazene base. Esterification of the hydroxyl groups of the OH-terminated PE star with 2,2-dichloroacetyl chloride led to (PE-Cl2)4 which was used as initiator (eight initiating atom transfer radical polymerization, ATRP, sites) for the synthesis of (PE-b-PMMA2)4 dendrimer-like stars by the ATRP of methyl methacrylate (MMA). All intermediates and final products were characterized by high temperature gel permeation chromatography and proton nuclear magnetic resonance spectroscopy. © 2016 The Royal Society of Chemistry.

  13. Effect of bovine serum albumin on the micellization of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) block copolymers in aqueous solutions by fluorescence spectroscopy

    Institute of Scientific and Technical Information of China (English)

    GUO Chen; WANG Jing; LIANG Xiangfeng; ZHENG Lili; LIU Huizhou

    2006-01-01

    Effect of bovine serum albumin (BSA) on the temperature-dependent association behavior of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) block copolymers was investigated using pyrene fluorescence spectroscopy. The critical micellization temperature (CMT) of pluronics in aqueous solution was increased by the addition of BSA. A closed association model was used to obtain the standard free energies (△G0), enthalpies (△H 0), and entropies (△S0) of micellization. The standard enthalpy and entropy of micellization for pluronic polymers in water were decreased with an increase of the BSA content. The more PPO component in the pluronic polymer, the higher the changed values of micellization enthalpy and entropy. The hydrophobic part of the pluronics, PPO, was responsible for the interaction between pluronics and BSA. Hydrophobic interaction between PPO and BSA was correlated to the alternation of the PPO-PPO interaction by the addition of BSA, which would shift the CMT toward higher temperature and alter the thermodynamic parameters of micellization for pluronics in aqueous solutions.

  14. “Pore-Like” Effects of Super-Molecular Self-Assembly on Molecular Diffusion of Poly(Ethylene Oxide-Poly(Propylene Oxide-Poly(Ethylene Oxide in Water

    Directory of Open Access Journals (Sweden)

    Konstantin Ulrich

    2012-05-01

    Full Text Available Molecular diffusion of triblock copolymers poly(ethylene oxide-poly(propylene oxide-poly(ethylene oxide in water was studied with the help of Pulsed Field Gradient NMR in the broad range of polymer weight fractions from 0.09 to 0.8. Owing to amphiphilic nature of the molecules, these block copolymers exhibit rich self-organization properties when mixed with water. In particular, at ambient temperatures they form micelles and three liquid crystalline mesophases: cubic, hexagonal, and lamellar. The corresponding super-molecular structure formations were studied with the same block copolymer and at the same temperature. Self-assembly of molecules was shown to produce “pore-like” effects on their self-diffusion properties by imposing severe constraints on the dimensionality of propagation. Diffusion in the hexagonal phase was shown to be quasi one-dimensional in the direction parallel to the long axis of the ordered molecular rods. In the lamellar phase, diffusion was found to be quasi two-dimensional, in the plane of the lamellar structures. The observed diffusion anisotropy was attributed to the effects of the specific molecular ordering on the mesoscopic length scale.

  15. Polyethylene glycol grafted flower-like cupric nano oxide for the hollow-fiber solid-phase microextraction of hexaconazole, penconazole, and diniconazole in vegetable samples.

    Science.gov (United States)

    Zendegi-Shiraz, Amene; Sarafraz-Yazdi, Ali; Es'haghi, Zarrin

    2016-08-01

    A simple, rapid, highly efficient, and reliable sample preparation method has been developed for the extraction and analysis of triazole pesticides from cucumber, lettuce, bell pepper, cabbage, and tomato samples. This new sorbent in the hollow-fiber solid-phase microextraction method is based on the synthesis of polyethylene glycol-polyethylene glycol grafted flower-like cupric oxide nanoparticles using sol-gel technology. Afterward, the analytes were analyzed by high-performance liquid chromatography with ultraviolet detection. The main parameters that affect microextraction efficiency were evaluated and optimized. This method has afforded good linearity ranges (0.5-50 000 ng/mL for hexaconazol, 0.012-50 000 ng/mL for penconazol, and 0.02-50 000 ng/mL for diniconazol), adequate precision (2.9-6.17%, n = 3), batch-to-batch reproducibility (4.33-8.12%), and low instrumental LODs between 0.003 and 0.097 ng/mL (n = 8). Recoveries and enrichment factors were 85.46-97.47 and 751-1312%, respectively.

  16. Influence of poly(ethylene oxide)-based copolymer on protein adsorption and bacterial adhesion on stainless steel: modulation by surface hydrophobicity.

    Science.gov (United States)

    Yang, Yi; Rouxhet, Paul G; Chudziak, Dorota; Telegdi, Judit; Dupont-Gillain, Christine C

    2014-06-01

    The aim of the present work is to study the adhesion of Pseudomonas NCIMB 2021, a typical aerobic marine microorganism, on stainless steel (SS) substrate. More particularly, the potential effect on adhesion of adsorbed poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer is investigated. Bacterial attachment experiments were carried out using a modified parallel plate flow chamber, allowing different surface treatments to be compared in a single experiment. The amount of adhering bacteria was determined via DAPI staining and fluorescence microscopy. X-ray photoelectron spectroscopy (XPS) was used to characterize the surface chemical composition of SS and hydrophobized SS before and after PEO-PPO-PEO adsorption. The adsorption of bovine serum albumin (BSA), a model protein, was investigated to test the resistance of PEO-PPO-PEO layers to protein adsorption. The results show that BSA adsorption and Pseudomonas 2021 adhesion are significantly reduced on hydrophobized SS conditioned with PEO-PPO-PEO. Although PEO-PPO-PEO is also found to adsorb on SS, it does not prevent BSA adsorption nor bacterial adhesion, which is attributed to different PEO-PPO-PEO adlayer structures on hydrophobic and hydrophilic surfaces. The obtained results open the way to a new strategy to reduce biofouling on metal oxide surfaces using PEO-PPO-PEO triblock copolymer.

  17. Oxidized wax as compatibilizer in linear low-density polyethylene-clay nanocomposites: x-ray diffraction and dynamic mechanical analysis.

    Science.gov (United States)

    Geethamma, V G; Luyt, Adriaan S

    2008-04-01

    Oxidized paraffin wax was used as a compatibilizer in composites of linear low-density polyethylene and layered nano silicate clays. X-ray diffraction analyses were carried out to investigate the crystalline morphology of five types of clays, oxidized wax, and their composites with LLDPE. The composites exhibited different X-ray diffraction and dynamic mechanical behaviour in the presence of different clays. Generally, the composites retained the partially crystalline behaviour of LLDPE, and no exfoliation was observed. Increased amount of wax did not change the morphology in most cases. The incorporation of clay resulted in an observable increase in the storage modulus of LLDPE. These values also increased with the addition of oxidized wax for most of the composites. The loss modulus increased with the amount of clay, irrespective of its nature. In most cases these values also increased with the incorporation of wax. The composites with 10% clay and 10% oxidized wax showed the highest storage and loss moduli, irrespective of the nature of the clay. The tan delta values did not change considerably with the addition of clay or wax.

  18. A mechanistic study explaining the synergistic viscosity increase obtained from polyethylene oxide (PEO) and {beta}-naphthalene sulfonate (BNS) in shotcrete

    Energy Technology Data Exchange (ETDEWEB)

    Pickelmann, J.; Plank, J., E-mail: sekretariat@bauchemie.ch.tum.de

    2012-11-15

    In shotcrete, a combination of polyethylene oxide (PEO) and {beta}-naphthalene sulfonate (BNS) is commonly applied to reduce rebound. Here, the mechanism for the synergistic viscosity increase resulting from this admixture combination was investigated via x-ray diffraction (XRD), infrared and nuclear magnetic resonance (NMR) spectroscopy. It was found that the electron-rich aromatic rings present in BNS donate electrons to the alkyl protons of PEO and thus increase the electron density there. This rare interaction is known as CH-{pi} interaction and leads to the formation of a supramolecular structure whereby PEO chains bind weakly to BNS molecules. Through this mechanism a polymer network exhibiting exceptionally high molecular weight and thus viscosity is formed. Among polycondensates, sulfanilic acid-phenol-formaldehyde (SPF) provides even higher synergy with PEO than BNS while melamine (PMS), acetone (AFS) or polycarboxylate (PCE) based superplasticizers do not work at all. Effectiveness of lignosulfonates is dependent on their degree of sulfonation.

  19. Effect of poly(ethylene oxide) on ionic conductivity and electrochemical properties of poly(vinylidenefluoride) based polymer gel electrolytes prepared by electrospinning for lithium ion batteries

    Science.gov (United States)

    Prasanth, Raghavan; Shubha, Nageswaran; Hng, Huey Hoon; Srinivasan, Madhavi

    2014-01-01

    Effect of poly(ethylene oxide) on the electrochemical properties of polymer electrolyte based on electrospun, non-woven membrane of PVdF is demonstrated. Electrospinning process parameters are controlled to get a fibrous membrane consisting of bead-free, uniformly dispersed thin fibers with diameter in the range of 1.5-1.9 μm. The membrane with good mechanical strength and porosity exhibits high uptake when activated with the liquid electrolyte of lithium salt in a mixture of organic solvents. The polymer gel electrolyte shows ionic conductivity of 4.9 × 10-3 S cm-1 at room temperature. Electrochemical performance of the polymer gel electrolyte is evaluated in Li/polymer electrolyte/LiFePO4 coin cell. Good performance with low capacity fading on charge-discharge cycling is demonstrated.

  20. Effects of deposition parameters on the electrical and mechanical properties of indium tin oxide films on polyethylene napthalate substrates deposited by radio frequency magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Bhagat, S.K.; Han, H.; Zoo, Y. [School of Materials and Flexible Display Center, Arizona State University, Tempe, Arizona, USA 85287 (United States); Lewis, J.; Grego, S. [RTI International Inc., Research Triangle Park, North Carolina, USA 27709 (United States); Lee, K.; Iyer, S. [Department of Electrical and Computer Engineering, North Carolina A and T State University, Greensboro, North Carolina, USA 27411 (United States); Alford, T.L. [School of Materials and Flexible Display Center, Arizona State University, Tempe, Arizona, USA 85287 (United States)], E-mail: alford@asu.edu

    2008-04-30

    The mechanical and electrical properties of indium tin oxide films on polyethylene naphthalate substrates are critical to the development of flexible displays. In the present study, mechanical and electrical properties are studied as a function of processing conditions, including radio frequency (rf) power, substrate temperature, and substrate plasma treatment. The results show that substrate temperature has the largest impact on mechanical performance. The best electrical performance is obtained from high substrate temperature and high rf power, while the best mechanical performance is obtained from high substrate temperature and low rf power. Plasma treatment gases influence electrical and mechanical properties, with mixture of nitrogen and hydrogen gases producing the best results. This work provides better initial understanding of the relationship between sputter process conditions and film properties and their influence on electrical and mechanical performance.

  1. Dielectric properties and structural dynamics of melt compounded hot-pressed poly(ethylene oxide)–organophilic montmorillonite clay nanocomposite films

    Indian Academy of Sciences (India)

    R J Sengwa; Shobhna Choudhary

    2012-02-01

    The dielectric properties of melt compounded hot-pressed nanocomposite films consisting of a poly(ethylene oxide) (PEO) and organophilic montmorillonite (OMMT) clay surface modified with trimethyl stearyl ammonium as filler with increasing amount up to 20 wt.% OMMT were investigated in a frequency range of 20 Hz–1 MHz at 30 °C. The predominance of OMMT exfoliated structures in PEO–OMMT nanocomposites were recognized by a decrease of the real part of complex dielectric function. OMMT concentration dependent dielectric and electric modulus relaxation times have revealed that the interactions compatibility between PEO molecules and dispersed OMMT nano-platelets in PEO matrix governs the PEO segmental dynamics. A.C. conductivity of these nanocomposites increases by two orders of magnitude in the experimental frequency range.

  2. Synthesis and Solution Properties of Double Hydrophilic Poly(ethylene oxide-block-poly(2-ethyl-2-oxazoline (PEO-b-PEtOx Star Block Copolymers

    Directory of Open Access Journals (Sweden)

    Felix H. Schacher

    2013-09-01

    Full Text Available We demonstrate the synthesis of star-shaped poly(ethylene oxide-block-poly(2-ethyl-2-oxazoline [PEOm-b-PEtOxn]x block copolymers with eight arms using two different approaches, either the “arm-first” or the “core-first” strategy. Different lengths of the outer PEtOx blocks ranging from 16 to 75 repeating units were used, and the obtained materials [PEO28-b-PEtOxx]8 were characterized via size exclusion chromatography (SEC, nuclear magnetic resonance spectroscopy (NMR, and Fourier-transform infrared spectroscopy (FT-IR measurements. First investigations regarding the solution behavior in water as a non-selective solvent revealed significant differences. Whereas materials synthesized via the “core-first” method seemed to be well soluble (unimers, aggregation occurred in the case of materials synthesized by the “arm-first” method using copper-catalyzed azide-alkyne click chemistry.

  3. Synthesis and Properties of High Strength Thin Film Composites of Poly(ethylene Oxide and PEO-PMMA Blend with Cetylpyridinium Chloride Modified Clay

    Directory of Open Access Journals (Sweden)

    Mohammad Saleem Khan

    2015-01-01

    Full Text Available Ion-conducting thin film composites of polymer electrolytes were prepared by mixing high MW poly(ethylene oxide (PEO, poly(methyl methacrylate (PMMA as a polymer matrix, cetylpyridinium chloride (CPC modified MMT as filler, and different content of LiClO4 by using solution cast method. The crystallinity, ionic conductivity (σ, and mechanical properties of the composite electrolytes and blend composites were evaluated by using XRD, AC impedance, and UTM studies, respectively. The modification of clay by CPC showed enhancement in the d-spacing. The loading of clay has effect on crystallinity of PEO systems. Blend composites showed better mechanical properties. Young’s modulus and elongation at break values showed increase with salt and clay incorporation in pure PEO. The optimum composition composite of PEO with 3.5 wt% of salt and 3.3 wt% of CPMMT exhibited better performance.

  4. Electrochemical pulsed deposition of platinum nanoparticles on indium tin oxide/polyethylene terephthalate as a flexible counter electrode for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Yu-Hsuan; Chen, Chih-Sheng [Department of Materials Engineering, Ming Chi University of Technology, New Taipei City 24301, Taiwan (China); Ma, Chen-Chi M. [Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Tsai, Chuen-Horng [Department of Engineering and System Science, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Hsieh, Chien-Kuo, E-mail: jack_hsieh@mail.mcut.edu.tw [Department of Materials Engineering, Ming Chi University of Technology, New Taipei City 24301, Taiwan (China)

    2014-11-03

    In this study, a pulsed-mode electrochemical deposition (Pulse-ECD) technique was employed to deposit platinum nanoparticles (PtNPs) on the indium tin oxide/polyethylene terephthalate (ITO/PET) substrate as a flexible counter electrode for dye-sensitized solar cells (DSSCs). The characteristic properties of the Pulse-ECD PtNPs were prepared and compared to the traditional (electron beam) Pt film. The surface morphologies of the PtNPs were examined by field emission scanning electron microscopy (FE-SEM) and the atomic force microscope (AFM). The FE-SEM results showed that our PtNPs were deposited uniformly on the ITO/PET flexible substrates via the Pulse-ECD technique. The AFM results indicated that the surface roughness of the pulsed PtNPs influenced the power conversion efficiency (PCE) of DSSCs, due to the high specific surface area of PtNPs which enhanced the catalytic activities for the reduction (I{sub 3}{sup −} to I{sup −}) of redox electrolyte. In combination with a N719 dye-sensitized TiO{sub 2} working electrode and an iodine-based electrolyte, the DSSCs with the PtNPs flexible counter electrode showed a PCE of 4.3% under the illumination of AM 1.5 (100 mW cm{sup −2}). The results demonstrated that the Pulse-ECD PtNPs are good candidate for flexible DSSCs. - Highlights: • We used indium tin oxide/polyethylene terephthalate as a flexible substrate. • We utilized pulse electrochemical deposition to deposit platinum nanoparticles. • We synthesized a flexible counter electrode for dye-sensitized solar cell (DSSC). • The power conversion efficiency of DSSC was measured to be 4.3%.

  5. Novel magnetic iron oxide nanoparticles coated with poly(ethylene imine)-g-poly(ethylene glycol) for potential biomedical application: synthesis, stability, cytotoxicity and MR imaging.

    Science.gov (United States)

    Schweiger, Christoph; Pietzonka, Clemens; Heverhagen, Johannes; Kissel, Thomas

    2011-04-15

    Magnetic iron oxide nanoparticles have found application as contrast agents for magnetic resonance imaging (MRI) and as switchable drug delivery vehicles. Their stabilization as colloidal carriers remains a challenge. The potential of poly(ethylene imine)-g-poly(ethylene glycol) (PEGPEI) as stabilizer for iron oxide (γ-Fe₂O₃) nanoparticles was studied in comparison to branched poly(ethylene imine) (PEI). Carrier systems consisting of γ-Fe₂O₃-PEI and γ-Fe₂O₃-PEGPEI were prepared and characterized regarding their physicochemical properties including magnetic resonance relaxometry. Colloidal stability of the formulations was tested in several media and cytotoxic effects in adenocarcinomic epithelial cells were investigated. Synthesized γ-Fe₂O₃ cores showed superparamagnetism and high degree of crystallinity. Diameters of polymer-coated nanoparticles γ-Fe₂O₃-PEI and γ-Fe₂O₃-PEGPEI were found to be 38.7 ± 1.0 nm and 40.4 ± 1.6 nm, respectively. No aggregation tendency was observable for γ-Fe₂O₃-PEGPEI over 12 h even in high ionic strength media. Furthermore, IC₅₀ values were significantly increased by more than 10-fold when compared to γ-Fe₂O₃-PEI. Formulations exhibited r₂ relaxivities of high numerical value, namely around 160 mM⁻¹ s⁻¹. In summary, novel carrier systems composed of γ-Fe₂O₃-PEGPEI meet key quality requirements rendering them promising for biomedical applications, e.g. as MRI contrast agents. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Investigation of space charge distribution of low-density polyethylene/GO-GNF (graphene oxide from graphite nanofiber) nanocomposite for HVDC application.

    Science.gov (United States)

    Kim, Yoon Jin; Ha, Son-Tung; Lee, Gun Joo; Nam, Jin Ho; Ryu, Ik Hyun; Nam, Su Hyun; Park, Cheol Min; In, Insik; Kim, Jiwan; Han, Chul Jong

    2013-05-01

    This paper reported a research on space charge distribution in low-density polyethylene (LDPE) nanocomposites with different types of graphene and graphene oxide (GO) at low filler content (0.05 wt%) under high DC electric field. Effect of addition of graphene oxide or graphene, its dispersion in LDPE polymer matrix on the ability to suppress space charge generation will be investigated and compared with MgO/LDPE nanocomposite at the same filler concentration. At an applied electric field of 80 kV/mm, a positive packet-like charge was observed in both neat LDPE, MgO/LDPE, and graphene/LDPE nanocomposites, whereas only little homogenous space charge was observed in GO/LDPE nanocomposites, especially with GO synthesized from graphite nano fiber (GNF) which is only -100 nm in diameter. Our research also suggests that dispersion of graphene oxide particles on the polymer matrix plays a significant role to the performance of nanocomposites on suppressing packet-like space charge. From these results, it is expected that nano-sized GO synthesized from GNF can be a promising filler material to LDPE composite for HVDC applications.

  7. Evaluation of the drug solubility and rush ageing on drug release performance of various model drugs from the modified release polyethylene oxide matrix tablets.

    Science.gov (United States)

    Shojaee, Saeed; Nokhodchi, Ali; Maniruzzaman, Mohammed

    2017-02-01

    Hydrophilic matrix systems are currently some of the most widely used drug delivery systems for controlled-release oral dosage forms. Amongst a variety of polymers, polyethylene oxide (PEO) is considered an important material used in pharmaceutical formulations. As PEO is sensitive to thermal oxidation, it is susceptible to free radical oxidative attack. The aim of this study was to investigate the stability of PEO based formulations containing different model drugs with different water solubility, namely propranolol HCl, theophylline and zonisamide. Both polyox matrices 750 and 303 grade were used as model carriers for the manufacture of tablets stored at 40 °C. The results of the present study suggest that the drug release from the matrix was affected by the length of storage conditions, solubility of drugs and the molecular weight of the polymers. Generally, increased drug release rates were prevalent in soluble drug formulations (propranolol) when stored at the elevated temperature (40 °C). In contrast, it was not observed with semi soluble (theophylline) and poorly soluble (zonisamide) drugs especially when formulated with PEO 303 polymer. This indicates that the main parameters controlling the drug release from fresh polyox matrices are the solubility of the drug in the dissolution medium and the molecular weight of the polymer. DSC traces indicated that that there was a big difference in the enthalpy and melting points of fresh and aged PEO samples containing propranolol, whereas the melting point of the aged polyox samples containing theophylline and zonisamide was unaffected. Graphical abstract ᅟ.

  8. The role of the PCM in reducing oxidative stress induced by radical initiated photoencapsulation of chondrocytes in poly(ethylene glycol) hydrogels.

    Science.gov (United States)

    Farnsworth, N; Bensard, C; Bryant, S J

    2012-11-01

    The objectives for this study were to determine whether radical initiated photopolymerizations typically employed for cell encapsulations lead to oxidative stress incurred by chondrocytes and whether the development of a pericellular matrix (PCM) decreases this oxidative stress and has longer-term benefits on chondrocyte function. Freshly isolated bovine chondrocytes were encapsulated in poly(ethylene glycol) (PEG) hydrogels devoid of a PCM or with a PCM, confirmed by immunocytochemistry (IC), and cultured for up to 2 weeks. Reactive oxygen species (ROS) production and damage to cell membrane by lipid peroxidation were accomplished using carboxy-2,7-difluorodihydrofluorescein diacetate (carboxy-H(2)DFFDA) and by malondialdehyde (MDA) content, respectively. Gene expression and proteoglycan synthesis were analyzed using reverse transcription (RT)-quantitative PCR (qPCR) and (35)SO(4) incorporation, respectively. The photopolymerization reaction, which alone generates radicals and extracellular ROS, led to oxidative stress in chondrocytes evidenced by increased intracellular ROS and lipid peroxidation. The presence of a PCM decreased intracellular ROS and abrogated membrane lipid peroxidation, improved aggrecan, collagen II and collagen VI expression, and enhanced proteoglycan synthesis. The development of the PCM prior to photoencapsulation in PEG hydrogels reduces oxidative stress and improves chondrocyte anabolic activity. Our data suggest this reduction occurs by decreased ROS diffusion into the cell and decreased membrane damage. Our findings suggest that minimizing oxidative stress, such as through the presence of a PCM, may have long-term beneficial effects on tissue elaboration when employing photopolymerizations to encapsulate chondrocytes for cartilage tissue engineering applications. Copyright © 2012 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  9. The study of polyethylene wax oxidation and graft modification%聚乙烯蜡氧化及接枝改性研究

    Institute of Scientific and Technical Information of China (English)

    王燕; 马沛岚

    2009-01-01

    The modified method of by-product polyethylene wax (PEW) of high density polyethylene production process has been studied,the result indicated that via catalyzed oxidation and maleic anhydride (MAH) grafting,the by-product PEW can produce carboxyl group or MAH polar group on the polymer chain,that can enhance the application value of the PEW greatly. By the air catalystic oxidation,when the oxidation temperature is 145 ~ 155 ℃ ,the air speed of flow is 5 ~ 6 m/s,the amount of duplicate match catalyst (M_1: M_2 = 1: 1) is 0. 4%~0. 5% ,the duration of oxidation is 6 h,the faint yellow oxidized polyethylene waxes which the acid value is 24.0 ~27.0 mg KOH/g can be obtained. By MAH grafting, at the optimum condition:reaction temperature 155℃,reaction time 5 h,the amount of initiator 2.0% , the amount of MAH 5% ,the grafted PEX which the acid value is 48.30 mg KOH/g can be obtained. By extrusion grafted, uses the automated continuous production method, at the condition of extrusion temperature 80 ℃~90℃, rotational speed 30 r/min, torque 0 ~ 4 N·m, and the amount of initiator and MAH respectively is 2.0% and 15% ,the acid value of product is 17.6 mg KOH/g.%高密度聚乙烯生产过程中副产聚乙烯蜡,采用空气催化氧化法和马来酸酐接枝法均可在聚合物分子链上生成羧基或马来酸酐极性基团,可大大提高聚乙烯蜡的应用价值.采用空气催化氧化法,氧化温度为145~155 ℃,空气流速为5~6 m/s,复配催化剂(M_1∶M_2=1∶1)量0.4%~0.5%,连续氧化6 h,可获得微黄色酸值为24.0~27.0 mg KOH/g的氧化聚乙烯蜡;采用马来酸酐接枝法最佳条件:反应温度155 ℃、反应时间5 h、引发剂加入量2.0%、MAH加入量5%,可获得酸值为48.30 mg KOH/g的接枝聚乙烯蜡.挤出接枝法采用自动化连续生产方法,在挤出温度80~90 ℃,转速30 r/min,扭矩0~4 N · m,引发剂和MAH加入量分别为2.0%和15%条件下,可得到酸值为17.6 mg KOH/g的接枝产品.

  10. Electrode-Impregnable and Cross-Linkable Poly(ethylene oxide)-Poly(propylene oxide)-Poly(ethylene oxide) Triblock Polymer Electrolytes with High Ionic Conductivity and a Large Voltage Window for Flexible Solid-State Supercapacitors.

    Science.gov (United States)

    Han, Jae Hee; Lee, Jang Yong; Suh, Dong Hack; Hong, Young Taik; Kim, Tae-Ho

    2017-10-04

    We present cross-linkable precursor-type gel polymer electrolytes (GPEs) that have large ionic liquid uptake capability, can easily penetrate electrodes, have high ion conductivity, and are mechanically strong as high-performance, flexible all-solid-state supercapacitors (SC). Our polymer precursors feature a hydrophilic-hydrophobic poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock main-chain structure and trifunctional silane end groups that can be multi-cross-linked with each other through a sol-gel process. The cross-linked solid-state electrolyte film with moderate IL content (200 wt %) shows a well-balanced combination of excellent ionic conductivity (5.0 × 10(-3) S cm(-1)) and good mechanical stability (maximum strain = 194%). Moreover, our polymer electrolytes have various advantages including high thermal stability (decomposition temperature > 330 °C) and the capability to impregnate electrodes to form an excellent electrode-electrolyte interface due to the very low viscosity of the precursors. By assembling our GPE-impregnated electrodes and solid-state GPE film, we demonstrate an all-solid-state SC that can operate at 3 V and provides an improved specific capacitance (112.3 F g(-1) at 0.1 A g(-1)), better rate capability (64% capacity retention until 20 A g(-1)), and excellent cycle stability (95% capacitance decay over 10 000 charge/discharge cycles) compared with those of a reference SC using a conventional PEO electrolyte. Finally, flexible SCs with a high energy density (22.6 W h kg(-1) at 1 A g(-1)) and an excellent flexibility (>93% capacitance retention after 5000 bending cycles) can successfully be obtained.

  11. Polyethylene Glycol 3350

    Science.gov (United States)

    Polyethylene glycol 3350 is used to treat occasional constipation. Polyethylene glycol 3350 is in a class of medications called ... Polyethylene glycol 3350 comes as a powder to be mixed with a liquid and taken by mouth. It ...

  12. Investigation of antioxidant and electron beam radiation effects on the thermal oxidation stability of low-density polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Ghaffari, Mehdi [Yazd Radiation Processing Center, P.O. Box 89175-389, Yazd (Iran, Islamic Republic of)], E-mail: md_ghaffari@yahoo.com; Ahmadian, Venus [Yazd Radiation Processing Center, P.O. Box 89175-389, Yazd (Iran, Islamic Republic of)

    2007-11-15

    Effect of various antioxidants on the thermal oxidation stability of LDPE and X-LDPE has been investigated. To achieve this purpose, miscellaneous commercial grade antioxidants such as Irganox 1010, Irganox1076, Irgafos168, Irganox B225, and Chimassorb 944 were selected. Then, formulations based on different content of antioxidant were prepared. The samples were crosslinked by exposure to electron beam irradiation. To assess the thermal oxidation stability of samples, oxidation induction time (OIT) test was accomplished on both the irradiated and unirradiated specimens. Ageing tests were carried out in order to evaluate the thermal oxidation stability of irradiated X-LDPE. The results indicate that Irganox 1010 is the most effective antioxidant amongst the selected ones, concerning thermal oxidation stability of LDPE, before and after aging test.

  13. Investigation of antioxidant and electron beam radiation effects on the thermal oxidation stability of low-density polyethylene

    Science.gov (United States)

    Ghaffari, Mehdi; Ahmadian, Venus

    2007-11-01

    Effect of various antioxidants on the thermal oxidation stability of LDPE and X-LDPE has been investigated. To achieve this purpose, miscellaneous commercial grade antioxidants such as Irganox 1010, Irganox1076, Irgafos168, Irganox B225, and Chimassorb 944 were selected. Then, formulations based on different content of antioxidant were prepared. The samples were crosslinked by exposure to electron beam irradiation. To assess the thermal oxidation stability of samples, oxidation induction time (OIT) test was accomplished on both the irradiated and unirradiated specimens. Ageing tests were carried out in order to evaluate the thermal oxidation stability of irradiated X-LDPE. The results indicate that Irganox 1010 is the most effective antioxidant amongst the selected ones, concerning thermal oxidation stability of LDPE, before and after aging test.

  14. Effects of a vanadium post-metallocene catalyst-induced polymer backbone inhomogeneity on UV oxidative degradation of the resulting polyethylene film

    KAUST Repository

    Atiqullah, M.

    2012-07-01

    A Group 5 post-metallocene precatalyst, (ONO)VCl(THF) 2 (ONO = a bis(phenolate)pyridine LX 2 pincer ligand), activated with modified methylaluminoxane (MMAO-3A) produced a linear ethylene homopolymer (nm-HomoPE)and an unusual inhomogeneous copolymer (nm-CopolyPE) with 1-hexene having very low backbone unsaturation. The nm-CopolyPE inhomogeneity was reflected in the distributions of short chain branches, 1-hexene composition, and methylene sequence length. The 1-hexene incorporation into the polyethylene backbone strongly depended on the molecular weight of the growing polymer chain. (ONO)VCl(THF) 2, because of site diversity and easier removal of a tertiary (vs. a secondary) hydrogen, produced a skewed short chain branching (SCB) profile, incorporating 1-hexene more efficiently in the low molecular weight region than in the high molecular weight region. The significant decrease in molecular weight by 1-hexene showed that the (ONO)VCl(THF) 2 catalytic sites were also highly responsive to chain-transfer directly to 1-hexene itself, producing vinyl and trans-vinylene termini. Subsequently, the effect of backbone inhomogeneity on the UV oxidative degradation of films made from both polyethylenes was investigated. The major functional group accumulated in the branched nm-CopolyPE film was carbonyl followed by carboxyl, then vinyl/ester, whereas that in the linear nm-HomoPE film was carboxyl. However, (carbonyl, carboxyl, vinyl, and ester) nm-CopolyPE film >> (carboxyl) nm-HomoPE film). The distributions of the tertiary C-H sites and methylene sequence length in the branched nm-CopolyPE film enhanced abstraction of H, decomposition of hydroperoxide group ROOH, and generation of carbonyl compounds as compared with those in the linear nm-HomoPE film. This clearly establishes the role played by the backbone inhomogeneity. The effect of short chain branches and sequence length distributions on peak melting temperature T pm, and most probably lamellar thickness L o, was

  15. Effect of the structure of commercial poly(ethylene oxide-b-propylene oxide) demulsifier bases on the demulsification of water-in-crude oil emulsions: elucidation of the demulsification mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Ramalho, Joao Batista V.S. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil). Centro de Pesquisas; Lechuga, Fernanda C.; Lucas, Elizabete F., E-mail: elucas@ima.ufrj.b [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Macromoleculas Profa. Eloisa Mano

    2010-07-01

    Water-in-crude oil emulsions are formed during petroleum production and asphaltenes play an important role in their stabilization. Demulsifiers are added to destabilize such emulsions,however the demulsification mechanism is not completely known. In this paper, the performances of commercial poly(ethylene oxide-b-propylene oxide) demulsifiers were studied using synthetic water-in-oil emulsions and model-systems (asphaltenes in organic solvent). No change in the asphaltene aggregate size induced by the demulsifier was observed. The demulsification performance decreased as the asphaltene aggregate size increased, so it can be suggested that the demulsification mechanism is correlated to the voids between the aggregates adsorbed on the water droplets surface. (author)

  16. Effect of the structure of commercial poly(ethylene oxide-b-propylene oxide demulsifier bases on the demulsification of water-in-crude oil emulsions: elucidation of the demulsification mechanism

    Directory of Open Access Journals (Sweden)

    João Batista V. S. Ramalho

    2010-01-01

    Full Text Available Water-in-crude oil emulsions are formed during petroleum production and asphaltenes play an important role in their stabilization. Demulsifiers are added to destabilize such emulsions,however the demulsification mechanism is not completely known. In this paper, the performances of commercial poly(ethylene oxide-b-propylene oxide demulsifiers were studied using synthetic water-in-oil emulsions and model-systems (asphaltenes in organic solvent. No change in the asphaltene aggregate size induced by the demulsifier was observed. The demulsification performance decreased as the asphaltene aggregate size increased, so it can be suggested that the demulsification mechanism is correlated to the voids between the aggregates adsorbed on the water droplets surface.

  17. Poly(ethylene glycol) dicarboxylate/poly(ethylene oxide) hydrogel film co-crosslinked by electron beam irradiation as an anti-adhesion barrier

    Energy Technology Data Exchange (ETDEWEB)

    Haryanto,; Singh, Deepti; Han, Sung Soo [Department of Advanced Organic Materials Engineering, Yeungnam University, Gyongbuk 712-749 (Korea, Republic of); Son, Jun Hyuk [Department of Ophthalmology, College of Medicine, Yeungnam University, Gyongbuk 712-749 (Korea, Republic of); Kim, Seong Cheol, E-mail: sckim07@ynu.ac.kr [Department of Advanced Organic Materials Engineering, Yeungnam University, Gyongbuk 712-749 (Korea, Republic of)

    2015-01-01

    The cross-linked poly(ethylene glycol) dicarboxylate (PEGDC)/poly(ethylene oxide) (PEO) and poly(ethylene glycol) dimethacrylate (PEGDMA)/(PEO) hydrogels were developed for possible biomedical applications such as an anti-adhesion barrier. Various contents of PEGDC/PEO film were irradiated using an electron beam with various beam intensities in order to obtain various degrees of crosslinked hydrogels. The optimum dose (300 kGy) and total crosslinker content of 10% were used to prepare crosslinked hydrogel films with three different compositions (10% PEGDC, 10% PEGDMA, 5% PEGDC–5% PEGDMA). Among them, 10% PEGDC hydrogel film exhibited the highest elongation at break (69.33 ± 6.87%) with high mechanical strength. 10% PEGDC hydrogel film showed the lowest hemolysis activity (6.03 ± 0.01%) and the highest tissue adherence (75.67 ± 1.15 cN). The result also indicated that the carboxyl groups in PEGDC affect the tissue adherence of hydrogel films via H-bonding interactions. In animal studies, 10% PEGDC anti-adhesion hydrogel film degraded within 3 weeks and demonstrated better anti-adhesive effect compared to Guardix-SG®. - Highlights: • The crosslinked PEGDC/PEO hydrogel was developed by e-beam irradiation. • 10% PEGDC hydrogel film showed the highest elongation at break and tissue adhesion. • The COOH group enhanced the tissue adherence of hydrogel films on the intestine. • 10% PEGDC hydrogel film demonstrated a good anti-adhesive effect in animal study. • All of the hydrogel films with 10% PEGDC degraded in vivo within three weeks.

  18. Dextran and Polymer Polyethylene Glycol (PEG Coating Reduce Both 5 and 30 nm Iron Oxide Nanoparticle Cytotoxicity in 2D and 3D Cell Culture

    Directory of Open Access Journals (Sweden)

    Alisa Morss Clyne

    2012-05-01

    Full Text Available Superparamagnetic iron oxide nanoparticles are widely used in biomedical applications, yet questions remain regarding the effect of nanoparticle size and coating on nanoparticle cytotoxicity. In this study, porcine aortic endothelial cells were exposed to 5 and 30 nm diameter iron oxide nanoparticles coated with either the polysaccharide, dextran, or the polymer polyethylene glycol (PEG. Nanoparticle uptake, cytotoxicity, reactive oxygen species (ROS formation, and cell morphology changes were measured. Endothelial cells took up nanoparticles of all sizes and coatings in a dose dependent manner, and intracellular nanoparticles remained clustered in cytoplasmic vacuoles. Bare nanoparticles in both sizes induced a more than 6 fold increase in cell death at the highest concentration (0.5 mg/mL and led to significant cell elongation, whereas cell viability and morphology remained constant with coated nanoparticles. While bare 30 nm nanoparticles induced significant ROS formation, neither 5 nm nanoparticles (bare or coated nor 30 nm coated nanoparticles changed ROS levels. Furthermore, nanoparticles were more toxic at lower concentrations when cells were cultured within 3D gels. These results indicate that both dextran and PEG coatings reduce nanoparticle cytotoxicity, however different mechanisms may be important for different size nanoparticles.

  19. Compression Molded Ultra High Molecular Weight Polyethylene-- Hydroxyapatite-Aluminum Oxide-Carbon Nanotube Hybrid Composites for Hard Tissue Replacement

    National Research Council Canada - National Science Library

    Ankur Gupta Garima Tripathi Debrupa Lahiri Kantesh Balani

    2013-01-01

    ...), bioinert aluminum oxide (Al2O3), and carbon nanotubes (CNTs) using compression molding. Phase and microstructural analysis suggests retention of UHMWPE and reinforcing phases in the compression molded composites...

  20. Processing, Characterization and Fretting Wear of Zinc Oxide and Silver Nanoparticles Reinforced Ultra High Molecular Weight Polyethylene Biopolymer Nanocomposite

    Science.gov (United States)

    Alam, Fahad; Kumar, Anil; Patel, Anup Kumar; Sharma, Rajeev K.; Balani, Kantesh

    2015-04-01

    Ultra-high molecular weight polyethylene (UHMWPE) is the most widely used biopolymer for articulating surfaces, such as an acetabular cup liner interfacing with a metal/ceramic femoral head. However, the formation of wear debris leads to the aseptic loosening of implants. Thus, in order to improve the life span via enhancing the fretting wear resistance, UHMWPE is reinforced with ZnO/Ag nanoparticles. It is envisaged that the ZnO/Ag addition will also exhibit antibacterial properties. In the current study, the synergetic effect of the reinforcement of ZnO/Ag nanoparticles (0-3 wt.% combinations) on the fretting wear behavior of a UHMWPE matrix is assessed. The phase characterization of compression- molded UHMWPE-Ag-ZnO biopolymer nanocomposites has elicited the retention of starting phases. All samples were processed at >98% density using compression molding. Silver and ZnO reinforcement showed enhanced hardness ~20.4% for U3A and 42.0% for U3Z. Fretting wear performance was evaluated at varying loads (5-15 N), keeping in mind the weight at different joints, with constant frequency (5 Hz) as well as amplitude of oscillation (100 µm). Laser surface profilometry showed change of wear volume from 8.6 × 10-5 mm3 for neat polymer to 5.8 × 10-5 mm3 with 1 wt.% Ag + 1 wt.% ZnO reinforcement (at 15 N load). Consequently, the mechanics of resistance offered by Ag and ZnO is delineated in the UHMWPE matrix. Further, S. aureus viability reduction is ~28.7% in cases with 1 wt.% Ag addition, ~42.5% with 1 wt.% ZnO addition, but synergistically increase to ~58.6% and 47.1% when each of Ag and ZnO is added with 1 wt.% and 3 wt.%, respectively (when compared to that of the UHMWPE control sample). Increased wear resistance and superior bioactivity and enhanced anti-bacterial properties of 1 wt.% Ag + 1 wt.% ZnO and 3 wt.% Ag + 3 wt.% ZnO shows the potential use of ZnO-Ag-UHMWPE biopolymer composites as an articulating surface.

  1. Understanding the performance of melt-extruded poly(ethylene oxide)-bicalutamide solid dispersions: characterisation of microstructural properties using thermal, spectroscopic and drug release methods.

    Science.gov (United States)

    Abu-Diak, Osama A; Jones, David S; Andrews, Gavin P

    2012-01-01

    In this article, we have prepared hot-melt-extruded solid dispersions of bicalutamide (BL) using poly(ethylene oxide) (PEO) as a matrix platform. Prior to preparation, miscibility of PEO and BL was assessed using differential scanning calorimetry (DSC). The onset of BL melting was significantly depressed in the presence of PEO, and using Flory-Huggins (FH) theory, we identified a negative value of -3.4, confirming miscibility. Additionally, using FH lattice theory, we estimated the Gibbs free energy of mixing which was shown to be negative, passing through a minimum at a polymer fraction of 0.55. Using these data, solid dispersions at drug-to-polymer ratios of 1:10, 2:10 and 3:10 were prepared via hot-melt extrusion. Using a combination of DSC, powder X-ray diffractometry and scanning electron microscopy, amorphous dispersions of BL were confirmed at the lower two drug loadings. At the 3:10 BL to PEO ratio, crystalline BL was detected. The percent crystallinity of PEO was reduced by approximately 10% in all formulations following extrusion. The increased amorphous content within PEO following extrusion accommodated amorphous BL at drug to polymer loadings up to 2:10; however, the increased amorphous domains with PEO following extrusion were not sufficient to fully accommodate BL at drug-to-polymer ratios of 3:10.

  2. Design and characterisation of a polyethylene oxide matrix with the potential use as a teat insert for prevention/treatment of bovine mastitis.

    Science.gov (United States)

    Bhattarai, Sushila; Alany, Raid G; Bunt, Craig R; Abdelkader, Hamdy; Rathbone, Michael J

    2015-01-01

    This manuscript reports (for the first time) on antibiotic-free polymeric inserts for the prevention and/or treatment of bovine mastitis. Polyethylene oxide (PEO)-based inserts were prepared using different concentrations of various hydrophilic polymers and water-soluble and water-insoluble drug-release-modifying excipients. A simple and scalable melt-extrusion method was employed to prepare the inserts. The prepared inserts were characterised for their dimension, rheological and mechanical properties. The in vitro release of a model bacteriostatic drug (salicylic acid) from the prepared inserts was studied to demonstrate the effectiveness and reproducibility of the melt-extrusion manufacturing method. Further, the in vitro stability of the inserts was evaluated using gel permeation chromatography (GPC) to monitor any change in molecular weight under real-time and accelerated storage conditions. The investigated inserts were stable at accelerated storage conditions over a period of 6 months. PEO inserts have the potential to serve a dual purpose, act as a physical barrier against pathogens invading the teat canal of cows and possibly control the release of a drug.

  3. β-NMR measurements of molecular-scale lithium-ion dynamics in poly(ethylene oxide)-lithium-salt thin films

    Science.gov (United States)

    McKenzie, Iain; Cortie, David L.; Harada, Masashi; Kiefl, Robert F.; Levy, C. D. Philip; MacFarlane, W. Andrew; McFadden, Ryan M. L.; Morris, Gerald D.; Ogata, Shin-Ichi; Pearson, Matthew R.; Sugiyama, Jun

    2017-06-01

    β -detected NMR (β -NMR) has been used to study the molecular-scale dynamics of lithium ions in thin films of poly(ethylene oxide) (PEO) containing either lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) or lithium trifluoroacetate (LiTFA) salts at monomer-to-salt ratios (EO/Li) of 8.3. The results are compared with previous β -NMR measurements on pure PEO and PEO with lithium triflate (LiOTf) at the same loading [McKenzie et al., J. Am. Chem. Soc. 136, 7833 (2014)]. Activated hopping of 8Li+ was observed in all of the films above ˜250 K, with the hopping parameters strongly correlated with the ionicity of the lithium salt rather than the polymer glass transition temperature. The pre-exponential factor increases exponentially with ionicity, while the activation energy for hopping increases approximately linearly, going from 6.3 ±0.2 kJ mol-1 in PEO:LiTFA to 17.8 ±0.2 kJ mol-1 in PEO:LiTFSI. The more rapid increase in the pre-exponential factor outweighs the effect of the larger activation energy and results in 8Li+ hopping being fastest in PEO followed by PEO:LiTFSI, PEO:LiOTf, and PEO:LiTFA.

  4. Formulation and in vitro evaluation of floating tablets of hydroxypropyl methylcellulose and polyethylene oxide using ranitidine hydrochloride as a model drug.

    Science.gov (United States)

    Gharti, Kp; Thapa, P; Budhathoki, U; Bhargava, A

    2012-10-01

    The present study was carried out with an objective of preparation and in vitro evaluation of floating tablets of hydroxypropyl methyl cellulose (HPMC) and polyethylene oxide (PEO) using ranitidine hydrochloride as a model drug. The floating tablets were based on effervescent approach using sodium bicarbonate a gas generating agent. The tablets were prepared by dry granulation method. The effect of polymers concentration and viscosity grades of HPMC on drug release profile was evaluated. The effect of sodium bicarbonate and stearic acid on drug release profile and floating properties were also investigated. The result of in vitro dissolution study showed that the drug release profile could be sustained by increasing the concentration of HPMC K15MCR and Polyox WSR303. The formulation containing HPMC K15MCR and Polyox WSR303 at the concentration of 13.88% showed 91.2% drug release at the end of 24 hours. Changing the viscosity grade of HPMC from K15MCR to K100MCR had no significant effect on drug release profile. Sodium bicarbonate and stearic acid in combination showed no significant effect on drug release profile. The formulations containing sodium bicarbonate 20 mg per tablet showed desired buoyancy (floating lag time of about 2 minutes and total floating time of >24 hours). The present study shows that polymers like HPMC K15MCR and Polyox WSR303 in combination with sodium bicarbonate as a gas generating agent can be used to develop sustained release floating tablets of ranitidine hydrochloride.

  5. Novel differential refractometry study of the enzymatic degradation kinetics of poly(ethylene oxide)-b-poly(epsilon-caprolactone) particles dispersed in water.

    Science.gov (United States)

    Lam, HiuFung; Gong, Xiangjun; Wu, Chi

    2007-02-22

    A poly(ethylene oxide)-b-poly(epsilon-caprolactone) (PEO-b-PCL) diblock copolymer was micronized into small micelle-like particles (approximately 80 nm) via dialysis-induced microphase inversion. The enzymatic biodegradation of the PCL portion of these particles in water was in situ investigated inside a recently developed novel differential refractometer. Using this refractometry method, we were able to monitor the real-time biodegradation via the refractive index change (Deltan) of the dispersion because Deltan is directly proportional to the particle mass concentration. We found that the degradation rate is proportional to either the polymer or enzyme concentration. Our results directly support previous speculation on the basis of the light-scattering data that the biodegradation follows the first-order kinetics for a given enzyme concentration. This study not only leads to a better understanding of the enzymatic biodegradation of PCL, but also demonstrates a novel, rapid, noninvasive, and convenient way to test the degradability of polymers.

  6. To immobilize polyethylene glycol-borate ester/lithium fluoride in graphene oxide/poly(vinyl alcohol for synthesizing new polymer electrolyte membrane of lithium-ion batteries

    Directory of Open Access Journals (Sweden)

    Y. F. Huang

    2017-01-01

    Full Text Available Polymer electrolyte membranes (PEMs are potentially applicable in lithium-ion batteries with high safety, low cost and good performance. Here, to take advantages of ionic conductivity and selectivity of borate ester-functionalized small molecules as well as structural properties of polymer nanocomposite, a strategy of immobilizing as-synthesized polyethylene glycol-borate ester/lithium fluoride (B-PEG/LiF in graphene oxide/poly(vinyl alcohol (GO/PVA to prepare a PEM is put forward. Chemical structure of the PEM is firstly characterized by 1H-, 11B- and 19F-nuclear magnetic resonance spectra, and Fourier transform infrared spectroscopy spectra, respectively, and then is further investigated under consideration of the interactions among PVA, B-PEG and LiF components. The immobilization of B-PEG/LiF in PVA-based structure is confirmed. As the interactions within electrolyte components can be further tuned by GO, ionic conductivity (~10–3 S·cm–1, lithium-ion transfer number (~0.49, and thermal (~273 °C/electrochemical (>4 V stabilities of the PEM can be obtained, and the feasibility of PEMs applied in a lithium-ion battery is also confirmed. It is believed that such PEM is a promising candidate as a new battery separator.

  7. What can we learn from ionic conductivity measurements in polymer electrolytes? A case study on poly(ethylene oxide) (PEO)-NaI and PEO-LiTFSI.

    Science.gov (United States)

    Stolwijk, Nicolaas A; Wiencierz, Manfred; Heddier, Christian; Kösters, Johannes

    2012-03-15

    We explore in detail what information on ionic diffusivity and ion pairing can be exclusively gained from combining accurate direct-current conductivity data in polymer electrolytes with a novel evaluation model. The study was performed on two prototype systems based on poly(ethylene oxide) (PEO) with known disparate ion-association properties, which are due to the dissimilar salt components being either sodium iodide (NaI) or lithium bis(trifluoromethane-sulfonyl)imide (LiN(CF(3)SO(2))(2) or LiTFSI). The temperature dependence of the conductivity can be described by an extended Vogel-Tammann-Fulcher (VTF) equation, which involves a Boltzmann factor containing the pair-formation enthalpy ΔH(p). We find a distinct increase of the positive ΔH(p) values with decreasing salt concentration and similarly clear trends for the pertinent VTF parameters. The analysis further reveals that PEO-NaI combines a high pair fraction with a high diffusivity of the I(-) ion. By contrast, PEO-LiTFSI appears to be characterized by a low ion-pairing tendency and a relatively low mobility of the bulky TFSI(-) ion. The observed marked differences between PEO-NaI and PEO-LiTFSI complexes of homologous composition are most pronounced at high temperatures and low salt concentrations.

  8. Preparation and characterization of chitosan-Polyethylene glycol-polyvinylpyrrolidone-coated superparamagnetic iron oxide nanoparticles as carrier system: Drug loading and in vitro drug release study.

    Science.gov (United States)

    Prabha, G; Raj, V

    2016-05-01

    In the present research work, the anticancer drug "curcumin" is loaded with Chitosan (CS)-polyethylene glycol (PEG)-polyvinylpyrrolidone (PVP) (CS-PEG-PVP) polymer nanocomposites coated with superparamagnetic iron oxide (Fe3 O4 ) nanoparticles. The system can be used for targeted and controlled drug delivery of anticancer drugs with reduced side effects and greater efficiency. The prepared nanoparticles were characterized by Fourier transmission infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Curcumin drug-loaded Fe3 O4 -CS, Fe3 O4 -CS- PEG and Fe3 O4 -CS-PEG-PVP nanoparticles exhibited the mean particle size in the range of 183 - 390 nm with a zeta potential value of 26 mV-41 mV as measured using Malvern Zetasizer. The encapsulation efficiency, loading capacity and in-vitro drug release behaviour of curcumin drug-loaded Fe3 O4 -CS, Fe3 O4 -CS-PEG, and Fe3 O4 -CS-PEG-PVP nanoparticles were studied using UV spectrophotometer. Besides, the cytotoxicity of the prepared nanoparticles using MTT assay was also studied. The curcumin drug release was examined at different pH medium (4.5 and 7.4) and temperature (37°C and 45°C), and it was proved that the drug release depends upon the pH medium and temperature in addition to the nature of matrix.

  9. Study on ion conductivity and crystallinity of composite polymer electrolytes based on poly(ethylene oxide)/poly(acrylonitrile) containing nano-sized Al2O3 fillers.

    Science.gov (United States)

    Kim, Mingyeong; Lee, Lyungyu; Jung, Yongju; Kim, Seok

    2013-12-01

    In this paper, composite polymer electrolytes were prepared by a blend of poly(ethylene oxide) (PEO) and poly(acrylonitrile) (PAN) as a polymer matrix, ethylene carbonate as a plasticizer, LiClO4 as a salt, and by containing a different content of nano-sized Al2O3. The composite films were prepared by using the solution casting method. The crystallinity and ionic conductivity of the polymer electrolytes was investigated using X-ray diffraction (XRD) and AC impedance method, respectively. The morphology of composite polymer electrolyte film was analyzed by SEM method. From the experimental results, by increasing the Al2O3 content, the crystallinity of PEO was reduced, and the ionic conductivity was increased. In particular, by a doping of 15 wt.% Al2O3 in PEO/PAN polymer blend, the CPEs showed the superior ionic conductivity. However, when Al2O3 content exceeds 15 wt.%, the ionic conductivity was decreased. From the surface morphology, it was concluded that the ionic conductivity was decreased because the CPEs showed a heterogenous morphology due to immiscibility or aggregation of the ceramic filler within the polymer matrix.

  10. High Ionic Conductivity of Composite Solid Polymer Electrolyte via In Situ Synthesis of Monodispersed SiO2 Nanospheres in Poly(ethylene oxide).

    Science.gov (United States)

    Lin, Dingchang; Liu, Wei; Liu, Yayuan; Lee, Hye Ryoung; Hsu, Po-Chun; Liu, Kai; Cui, Yi

    2016-01-13

    High ionic conductivity solid polymer electrolyte (SPE) has long been desired for the next generation high energy and safe rechargeable lithium batteries. Among all of the SPEs, composite polymer electrolyte (CPE) with ceramic fillers has garnered great interest due to the enhancement of ionic conductivity. However, the high degree of polymer crystallinity, agglomeration of ceramic fillers, and weak polymer-ceramic interaction limit the further improvement of ionic conductivity. Different from the existing methods of blending preformed ceramic particles with polymers, here we introduce an in situ synthesis of ceramic filler particles in polymer electrolyte. Much stronger chemical/mechanical interactions between monodispersed 12 nm diameter SiO2 nanospheres and poly(ethylene oxide) (PEO) chains were produced by in situ hydrolysis, which significantly suppresses the crystallization of PEO and thus facilitates polymer segmental motion for ionic conduction. In addition, an improved degree of LiClO4 dissociation can also be achieved. All of these lead to good ionic conductivity (1.2 × 10(-3) S cm(-1) at 60 °C, 4.4 × 10(-5) S cm(-1) at 30 °C). At the same time, largely extended electrochemical stability window up to 5.5 V can be observed. We further demonstrated all-solid-state lithium batteries showing excellent rate capability as well as good cycling performance.

  11. Reconfigurable Ion Gating of 2H-MoTe2 Field-Effect Transistors Using Poly(ethylene oxide)-CsClO4 Solid Polymer Electrolyte.

    Science.gov (United States)

    Xu, Huilong; Fathipour, Sara; Kinder, Erich W; Seabaugh, Alan C; Fullerton-Shirey, Susan K

    2015-05-26

    Transition metal dichalcogenides are relevant for electronic devices owing to their sizable band gaps and absence of dangling bonds on their surfaces. For device development, a controllable method for doping these materials is essential. In this paper, we demonstrate an electrostatic gating method using a solid polymer electrolyte, poly(ethylene oxide) and CsClO4, on exfoliated, multilayer 2H-MoTe2. The electrolyte enables the device to be efficiently reconfigured between n- and p-channel operation with ON/OFF ratios of approximately 5 decades. Sheet carrier densities as high as 1.6 × 10(13) cm(-2) can be achieved because of a large electric double layer capacitance (measured as 4 μF/cm(2)). Further, we show that an in-plane electric field can be used to establish a cation/anion transition region between source and drain, forming a p-n junction in the 2H-MoTe2 channel. This junction is locked in place by decreasing the temperature of the device below the glass transition temperature of the electrolyte. The ideality factor of the p-n junction is 2.3, suggesting that the junction is recombination dominated.

  12. A new solid polymer electrolyte incorporating Li10GeP2S12 into a polyethylene oxide matrix for all-solid-state lithium batteries

    Science.gov (United States)

    Zhao, Yanran; Wu, Chuan; Peng, Gang; Chen, Xiaotian; Yao, Xiayin; Bai, Ying; Wu, Feng; Chen, Shaojie; Xu, Xiaoxiong

    2016-01-01

    Li10GeP2S12 (LGPS) is incorporated into polyethylene oxide (PEO) matrix to fabricate composite solid polymer electrolyte (SPE) membranes. The lithium ion conductivities of as-prepared composite membranes are evaluated, and the optimal composite membrane exhibits a maximum ionic conductivity of 1.21 × 10-3 S cm-1 at 80 °C and an electrochemical window of 0-5.7 V. The phase transition behaviors for electrolytes are characterized by DSC, and the possible reasons for their enhanced ionic conductivities are discussed. The LGPS microparticles, acting as active fillers incorporation into the PEO matrix, have a positive effect on the ionic conductivity, lithium ion transference number and electrochemical stabilities. In addition, two kinds of all-solid-state lithium batteries (LiFeO4/SPE/Li and LiCoO2/SPE/Li) are fabricated to demonstrate the good compatibility between this new SPE membrane and different electrodes. And the LiFePO4/Li battery exhibits fascinating electrochemical performance with high capacity retention (92.5% after 50 cycles at 60 °C) and attractive capacities of 158, 148, 138 and 99 mAh g-1 at current rates of 0.1 C, 0.2 C, 0.5 C and 1 C at 60 °C, respectively. It is demonstrated that this new composite SPE should be a promising electrolyte applied in solid state batteries based on lithium metal electrode.

  13. Polyethylene Oxide Films Polymerized by Radio Frequency Plasma-Enhanced Chemical Vapour Phase Deposition and Its Adsorption Behaviour of Platelet-Rich Plasma

    Science.gov (United States)

    Hu, Wen-Juan; Xie, Fen-Yan; Chen, Qiang; Weng, Jing

    2008-10-01

    We present polyethylene oxide (PEO) functional films polymerized by rf plasma-enhanced vapour chemical deposition (rf-PECVD) on p-Si (100) surface with precursor ethylene glycol dimethyl ether (EGDME) and diluted Ar in pulsed plasma mode. The influences of discharge parameters on the film properties and compounds are investigated. The film structure is analysed by Fourier transform infrared (FTIR) spectroscopy. The water contact angle measurement and atomic force microscope (AFM) are employed to examine the surface polarity and to detect surface morphology, respectively. It is concluded that the smaller duty cycle in pulsed plasma mode contributes to the rich C-O-C (EO) group on the surfaces. As an application, the adsorption behaviour of platelet-rich plasma on plasma polymerization films performed in-vitro is explored. The shapes of attached cells are studied in detail by an optic invert microscope, which clarifies that high-density C-O-C groups on surfaces are responsible for non-fouling adsorption behaviour of the PEO films.

  14. Polyethylene Oxide Films Polymerized by Radio Frequency Plasma-Enhanced Chemical Vapour Phase Deposition and Its Adsorption Behaviour of Platelet-Rich Plasma

    Institute of Scientific and Technical Information of China (English)

    HU Wen-Juan; XIE Fen-Yan; CHEN Qiang; WENG Jing

    2008-01-01

    We present polyethylene oxide (PEO) functional films polymerized by rf plasma-enhanced vapour chemical deposition (rf-PECVD) on p-Si (100) surface with precursor ethylene glycol dimethyl ether (EGDME) and diluted Ar in pulsed plasma mode. The influences of discharge parameters on the film properties and compounds are investigated. The film structure is analysed by Fourier transform infrared (FTIR) spectroscopy. The water contact angle measurement and atomic force microscope (AFM) are employed to examine the surface polarity and to detect surface morphology, respectively. It is concluded that the smaller duty cycle in pulsed plasma mode contributes to the rich C-O-C (EO) group on the surfaces. As an application, the adsorption behaviour of platelet-rich plasma on plasma polymerization films performed in-vitro is explored. The shapes of attached cells are studied in detail by an optic invert microscope, which clarifies that high-density C-O-C groups on surfaces are responsible for non-fouling adsorption behaviour of the PEO films.

  15. Conformational and Dynamic Properties of Poly(ethylene oxide) in an Ionic Liquid: Development and Implementation of a First-Principles Force Field.

    Science.gov (United States)

    McDaniel, Jesse G; Choi, Eunsong; Son, Chang-Yun; Schmidt, J R; Yethiraj, Arun

    2016-01-14

    The conformational properties of polymers in ionic liquids are of fundamental interest but not well understood. Atomistic and coarse-grained molecular models predict qualitatively different results for the scaling of chain size with molecular weight, and experiments on dilute solutions are not available. In this work, we develop a first-principles force field for poly(ethylene oxide) (PEO) in the ionic liquid 1-butyl 3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) using symmetry adapted perturbation theory (SAPT). At temperatures above 400 K, simulations employing both the SAPT and OPLS-AA force fields predict that PEO displays ideal chain behavior, in contrast to previous simulations at lower temperature. We therefore argue that the system shows a transition from extended to more compact configurations as the temperature is increased from room temperature to the experimental lower critical solution temperature. Although polarization is shown to be important, its implicit inclusion in the OPLS-AA force is sufficient to describe the structure and energetics of the mixture. The simulations emphasize the difference between ionic liquids from typical solvents for polymers.

  16. Full-Color Emissive Poly(Ethylene Oxide) Electrospun Nanofibers Containing a Single Hyperbranched Conjugated Polymer for Large-Scale, Flexible Light-Emitting Sheets.

    Science.gov (United States)

    Kim, Jongho; Lee, Taek Seung

    2016-02-01

    White-light-emitting protocols based on organic materials have received much attention in the academic and industrial fields because of their potential applications in full-color displays and back-lighting units for liquid crystal displays. Here, the attempt is made to fabricate white-light-emitting, electrospun poly(ethylene oxide) (PEO) sheets containing controlled concentrations of a single light-emitting material composed of a type of hyperbranched conjugated polymer (HCP). The HCPs used here have the unique property of exhibiting a variety of fluorescence colors in the electrospun matrix that is caused by the different distances between HCP chains depending on their concentrations, leading to different degrees of intermolecular energy transfer. Therefore, the emission colors of the PEO sheets can be easily manipulated by simply varying the HCP concentrations in the PEO matrix. The resulting method for fabricating nanofibers comprising light-emitting materials in the polymer matrix has great potential for easy fabrication of cost-effective, flexible light-emitting system.

  17. Biological and Tribological Assessment of Poly(Ethylene Oxide Terephthalate)/Poly(Butylene Terephthalate), Polycaprolactone, and Poly (L\\DL) Lactic Acid Plotted Scaffolds for Skeletal Tissue Regeneration.

    Science.gov (United States)

    Hendrikson, Wilhelmus J; Zeng, Xiangqiong; Rouwkema, Jeroen; van Blitterswijk, Clemens A; van der Heide, Emile; Moroni, Lorenzo

    2016-01-21

    Additive manufactured scaffolds are fabricated from three commonly used biomaterials, polycaprolactone (PCL), poly (L\\DL) lactic acid (P(L\\DL)LA), and poly(ethylene oxide terephthalate)/poly(butylene terephthalate) (PEOT/PBT). Scaffolds are compared biologically and tribologically. Cell-seeded PEOT/PBT scaffolds cultured in osteogenic and chondrogenic differentiation media show statistical significantly higher alkaline phosphatase (ALP) activity/DNA and glycosaminoglycans (GAG)/DNA ratios, followed by PCL and P(L\\DL)LA scaffolds, respectively. The tribological performance is assessed by determining the friction coefficients of the scaffolds at different loads and sliding velocities. With increasing load or decreasing sliding velocity, the friction coefficient value decreases. PEOT/PBT show to have the lowest friction coefficient value, followed by PCL and P(L\\DL)LA. The influence of the scaffold architecture is further determined with PEOT/PBT. Reducing of the fiber spacing results in a lower friction coefficient value. The best and the worst performing scaffold architecture are chosen to investigate the effect of cell culture on the friction coefficient. Matrix deposition is low in the cell-seeded scaffolds and the effect is, therefore, undetermined. Taken together, our studies show that PEOT/PBT scaffolds support better skeletal differentiation of seeded stromal cells and lower friction coefficient compared to PCL and P(L/DL)A scaffolds.

  18. SPHERULITIC STRUCTURE AND MORPHOLOGY OF POLY(ETHYLENE SUCCINATE)/POLY(ETHYLENE OXIDE) (PES/PEO) BLENDS WITH ONE-STEP CRYSTALLIZATION

    Institute of Scientific and Technical Information of China (English)

    Jie-ping Liu; Shuan-gai He; Xiao-ping Qiao

    2008-01-01

    The spherlitic structure and morphology development of poly(ethylene succinate)/poly(ethylene oxide) (PES/PEO) blends with one-step crystallization behavior were observed by means of polarizing optical microscope.It was found that the pure PES spherulite in which the adequate quantity of PEO melt existed in the interlamellar regions,and the blending spherulite formed by both PES and PEO lamellae could form simultaneously.When the two types of spherulites contacted with each other the front of the blending spherulite could penetrate into the pure PES spherulite to grow continually.This penetration growth behavior was also observed when the mini-crystal particles of the PES component were formed at lower crystallization temperatures.The kinetics analysis showed that the penetration growth rate was faster than that in the original melt.It was evidenced that the increasing of growth rate and the formation of new growth site should be the typical characteristics of interpenetrated growth in binary crystalline polymer blends.

  19. The Influence of Irradiation and Accelerated Aging on the Mechanical and Tribological Properties of the Graphene Oxide/Ultra-High-Molecular-Weight Polyethylene Nanocomposites

    Directory of Open Access Journals (Sweden)

    Guodong Huang

    2016-01-01

    Full Text Available Graphene oxide/ultra-high-molecular-weight polyethylene (GO/UHMWPE nanocomposite is a potential and promising candidate for artificial joint applications. However, after irradiation and accelerated aging, the mechanical and tribological behaviors of the nanocomposites are still unclear and require further investigation. GO/UHMWPE nanocomposites were successfully fabricated using ultrasonication dispersion, ball-milling, and hot-pressing process. Then, the nanocomposites were irradiated by gamma ray at doses of 100 kGy. Finally, GO/UHMWPE nanocomposites underwent accelerated aging at 80°C for 21 days in air. The mechanical and tribological properties of GO/UHMWPE nanocomposites have been evaluated after irradiation and accelerated aging. The results indicated that the incorporation of GO could enhance the mechanical, wear, and antiscratch properties of UHMWPE. After irradiation, these properties could be further enhanced, compared to unirradiated ones. After accelerated aging, however, these properties have been significantly reduced when compared to unirradiated ones. Moreover, GO and irradiation can synergistically enhance these properties.

  20. Distribution analysis of ultra-high molecular mass poly(ethylene oxide) containing silica particles by size-exclusion chromatography with dual light-scattering and refractometric detection.

    Science.gov (United States)

    Porsch, Bedrich; Welinder, Anette; Körner, Anna; Wittgren, Bengt

    2005-03-18

    Two different size-exclusion chromatography (SEC) systems, connected in-line either to a low-angle light scattering (LALS) or to a multiangle light scattering (MALS) detector, are employed for determination of molecular mass distributions (MMD) of poly(ethylene oxide) (PEO) samples having a weight average molecular mass up to eight millions. The detrimental effect of the presence of strongly scattering silica particles in the samples on the light scattering signal can be eliminated using a suitable sample dissolution procedure utilizing silica solubility in aqueous mobile phase. The selection of flow-rate and sample concentration have a large impact on the obtained results. Hydrodynamic retardation phenomena and nonlinearity effects are shown to introduce severe errors in the molecular mass distributions unless flow-rate and sample concentration are kept at sufficiently low levels. Self-compensating ability of the dual detection in flow-rate effects is shown to be the main advantage here. A good agreement between the results obtained using LALS and MALS detection is found provided that a carefully selected angular extrapolation procedure is used in the case of MALS data. Thus, using carefully selected experimental conditions, SEC with light-scattering (LS) and refractometric detection proved to be an efficient technique for MMD characterisation also of ultra-high molecular mass (UHM) PEO polymers.

  1. Imaging and Chemotherapeutic Comparisons of Iron Oxide Nanoparticles Chemically and Physically Coated with Poly(ethylene glycol)-b-Poly(ε-caprolactone)-g-Poly(acrylic acid).

    Science.gov (United States)

    Chen, Guo-Jing; Hsu, Chin; Ke, Jyun-Han; Wang, Li-Fang

    2015-06-01

    We designed a new copolymer, poly(ethylene glycol)-block-poly(ε-caprolactone)-graft-poly(acrylic acid) (PAA-PEC), which could be chemically and physically coated onto iron oxide (Fe3O4) nanoparticles for theranostic applications. The chemically PAA-PEC-coated Fe3O4 nanoparticles (PAA-PEC-IO) were prepared using the carboxylic groups of PAA-PEC to bind the Fe3O4 nanoparticles during a co-precipitation reaction. Because of the amphiphilic properties of PAA-PEC, the compound self-assembled into a core-shell structure. The hydrophobic oleic acid-coated Fe3O4 nanoparticles could then be physically encapsulated inside the hydrophobic core of PAA-PEC (PAA-PEC-OA-IO) using an emulsion technique. A similar amount of iron content was controlled in both the PAA-PEC-IO and PAA-PEC-OA-IO (-23%). The particle diameters, morphologies, superparamagnetism, drug loading efficiency, and transversal relaxivity (r2) were studied and compared between the two magnetic nanoparticles. All results displayed the chemically-synthesized PAA-PEC-IO nanoparticles had higher potential than did the physically-synthesized PAA-PEC-OA-IO as an MRI contrast agent and a drug delivery carrier. Rodamine123-linked PAA-PEC-IO (PAA-PEC-IO-Rh123) was used as a molecular probe. Flow cytometric diagrams indicated that cellular internalization of PAA-PEC-IO occurred primarily through clathrin-mediated endocytosis.

  2. Interactions of silica nanoparticles with poly(ethylene oxide) and poly(acrylic acid): effect of the polymer molecular weight and of the surface charge.

    Science.gov (United States)

    Joksimovic, R; Prévost, S; Schweins, R; Appavou, M-S; Gradzielski, M

    2013-03-15

    The properties and the structure of polymer-modified silica nanoparticles were investigated by several characterization methods, with an emphasis on scattering techniques. Both bare and amino functionalized nanoparticles were used. To determine the effect of the charge, the polymer used was either nonionic poly(ethylene oxide) (PEO) or partially deprotonated poly(acrylic acid) (PAA). The particles coated with PEO were investigated by small-angle neutron scattering using the method of external contrast variation to observe the polymer coverage. The quantity adsorbed was found to be increasing with the molecular weight, and the surface type, bare or aminated, did not have a significant influence on the quantity adsorbed. The adsorption of PAA on positively charged aminated particles was investigated by dynamic light scattering and zeta potential measurements. A charge reversal, from positive to negative, was induced by the presence of PAA. Through the derivation of the structure factor, small-angle X-ray scattering provided significant information on the formation of aggregates at low PAA concentrations.

  3. Organic-inorganic random copolymers from methacrylate-terminated poly(ethylene oxide) with 3-methacryloxypropylheptaphenyl polyhedral oligomeric silsesquioxane: synthesis via RAFT polymerization and self-assembly behavior.

    Science.gov (United States)

    Wei, Kun; Li, Lei; Zheng, Sixun; Wang, Ge; Liang, Qi

    2014-01-14

    In this contribution, we report the synthesis of organic-inorganic random polymers from methacrylate-terminated poly(ethylene oxide) (MAPEO) (Mn = 950) and 3-methacryloxypropylheptaphenyl polyhedral oligomeric silsesquioxane (MAPOSS) macromers via reversible addition-fragmentation chain transfer (RAFT) polymerization with 4-cyano-4-(thiobenzoylthio) valeric acid (CTBTVA) as the chain transfer agent. The organic-inorganic random copolymers were characterized by means of (1)H NMR spectroscopy, gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). The results of GPC indicate that the polymerizations were carried out in a controlled fashion. Transmission electron microscopy (TEM) showed that the organic-inorganic random copolymers in bulk were microphase-separated and the POSS microdomains were formed via POSS-POSS interactions. In aqueous solutions the organic-inorganic random copolymers were capable of self-assembling into spherical nanoobjects as evidenced by transmission electron microscopy (TEM) and dynamic laser scattering (DLS). The self-assembly behavior of the organic-inorganic random copolymers was also found to occur in the mixtures with the precursors of epoxy. The nanostructures were further fixed via subsequent curing reaction and thus the organic-inorganic nanocomposites were obtained. The formation of nanophases in epoxy thermosets was confirmed by transmission electron microscopy (TEM) and dynamic mechanical thermal analysis (DMTA). The organic-inorganic nanocomposites displayed the enhanced surface hydrophobicity as evidenced by surface contact angle measurements.

  4. Chemical modification of wheat protein-based natural polymers: grafting and cross-linking reactions with poly(ethylene oxide) diglycidyl ether and ethyl diamine.

    Science.gov (United States)

    Kurniawan, Lusiana; Qiao, Greg G; Zhang, Xiaoqing

    2007-09-01

    Mobile poly(ethylene oxide) diglycidyl ether (PEODGE) segments were chemically grafted onto a soluble wheat protein (WP), and different network structures were formed via coupling reactions with ethyl diamine (EDA) in different PEODGE/EDA (PE) ratios. When the PE ratio was 1:1, linear PEs were the predominant segments grafted onto WP chains and the whole WP-PEODGE-EDA (WPE) system was still soluble with an increased molecular weight. Reducing the amount of EDA in the systems produced insoluble cross-linked WPE networks. The broad distribution of network structures and chain mobility resulted in a broad glass transition for the WPE materials. However, the glass transition started at lower temperatures, and the materials became flexible at room temperature. The PE segments were present in all rigid, intermediate, and mobile phases in WPE networks, while the proportion of mobile WP chains was increased as a result of the plasticization effect from the mobile PE segments. The mobility of the most mobile component lipid was also restricted to some extent when forming the cross-linked WPE networks. The study demonstrated that the formation of different network structures with PE segments could significantly improve the flexibility of WP materials, vary the solubility, and modify the mechanical performance of WP-based natural polymer materials.

  5. Analysis of residual crosslinking agent content in UV cross-linked poly(ethylene oxide hydrogels for dermatological application by gas chromatography

    Directory of Open Access Journals (Sweden)

    Rachel Shet Hui Wong

    2016-10-01

    Full Text Available Acrylates have been widely used in the synthesis of pharmaceutical polymers. The quantitation of residual acrylate monomers is vital as they are strong irritants and allergens, but after polymerization, are relatively inert, causing no irritation and allergies. Poly(ethylene oxide (PEO hydrogels were prepared using pentaerythritol tetra-acrylate (PETRA as UV crosslinking agent. A simple, accurate, and robust quantitation method was developed based on gas chromatographic techniques (GC, which is suitable for routine analysis of residual PETRA monomers in these hydrogels. Unreacted PETRA was initially identified using gas chromatography–mass spectrometry (GC–MS. The quantitation of analyte was performed and validated using gas chromatography equipped with a flame ionization detector (GC–FID. A linear relationship was obtained over the range of 0.0002%–0.0450% (m/m with a correlation coefficient (r2 greater than 0.99. The recovery (>90%, intra-day precision (%RSD <0.67, inter-day precision (%RSD <2.5%, and robustness (%RSD <1.62% of the method were within the acceptable values. The limit of detection (LOD and limit of quantitation (LOQ were 0.0001% (m/m and 0.0002% (m/m, respectively. This assay provides a simple and quick way of screening for residual acrylate monomer in hydrogels.

  6. The development of poly(ethylene oxide) gas membranes%聚氧化乙烯气体分离膜的发展

    Institute of Scientific and Technical Information of China (English)

    赵红永; 曹义鸣; 康国栋; 丁晓莉; 袁权

    2011-01-01

    聚氧化乙烯[poly(ethylene oxide),PEO]类膜材料合有大量与CO2有很强相互作用的醚氧基团,使得它具有很高的CO2/light gases(例如:H2、N2、CH4)溶解选择性,因此带来很高的CO2/light gases选择性.介绍了具有高溶解选择性CO2气体分离膜材料的筛选,重点叙述了PEO类膜材料的发展以及目前主要的PEO类膜材料的气体分离性能.当PEO含量达到足够高时,PEO类膜材料的CO2/light gases选择性大小基本相同,而它们的CO2透气性随着膜材料链段结构的不同而有较大不同.%Membrane materials of poly(ethylene oxide) (PEO) containing numbers of ether oxygen groups, which has favorable interaction with CO2, has high solubility selectivity of Coz/light gases resulting in high selectivity of CO2/light gases. The screenings of membrane materials with high solubility selectivity for separating CO2 was introduced. The development and gas separation properties of main PEO membrane materials were described emphatically. When the content of PEO reaches high enough, the PEO membrane materials have the almost closer solubility selectivity of CO2/light gases and different CO2 permeability because of the different chain structures of these membrane materials.

  7. Synthesis and dose interval dependent hepatotoxicity evaluation of intravenously administered polyethylene glycol-8000 coated ultra-small superparamagnetic iron oxide nanoparticle on Wistar rats.

    Science.gov (United States)

    Rajan, Balan; Sathish, Shanmugam; Balakumar, Subramanian; Devaki, Thiruvengadam

    2015-03-01

    Superparamagnetic iron oxide nanoparticles are being used in medical imaging, drug delivery, cancer therapy, and so on. However, there is a direct need to identify any nanotoxicity associated with these nanoparticles. However uncommon, drug-induced liver injury (DILI) is a major health concern that challenges pharmaceutical industry and drug regulatory agencies alike. In this study we have synthesized and evaluated the dose interval dependent hepatotoxicity of polyethylene glycol-8000 coated ultra-small superparamagnetic iron oxide nanoparticles (PUSPIOs). To assess the hepatotoxicity of intravenously injected PUSPIOs, alterations in basic clinical parameters, hematological parameters, hemolysis assay, serum levels of liver marker enzymes, serum and liver lipid peroxidation (LPO) levels, enzymatic antioxidant levels, and finally histology of liver, kidney, spleen, lung, brain, and heart tissues were studied in control and experimental Wistar rat groups over a 30-day period. The results of our study showed a significant increase in the aspartate transaminase (AST) enzyme activity at a dose of 10mg/kg b.w. PUSPIOs twice a week. Besides, alanine transaminase (ALT), alkaline phosphatase (ALP), and gamma-glutamyl transferase (γGT) enzyme activity showed a slender increase when compared with control experimental groups. A significant increase in the serum and liver LPO levels at a dose of 10mg/kg b.w. PUSPIOs twice a week was also observed. Histological analyses of liver, kidney, spleen, lung, brain and heart tissue samples showed no obvious uncharacteristic changes. In conclusion, PUSPIOs were found to posses excellent biocompatibility and Wistar rats showed much better drug tolerance to the dose of 10mg/kg b.w. per week than the dose of 10mg/kg b.w. twice a week for the period of 30 days.

  8. Comparison of stabilization by Vitamin E and 2,6-di-tert-butylphenols during polyethylene radio-thermal-oxidation

    Science.gov (United States)

    Richaud, Emmanuel

    2014-10-01

    This paper reports a compilation of data for PE+Vitamin E and 2,6-di-tert-butylphenols oxidation in radio-thermal ageing. Data unambiguously show that Vitamin E reacts with Prad and POOrad whereas 2,6-di-tert-butyl phenols only react with POOrad. Kinetic parameters of the stabilization reactions for both kinds of antioxidants were tentatively extracted from phenol depletion curves, and discussed regarding the structure of the stabilizer. They were also used for completing an existing kinetic model used for predicting the stabilization by antioxidants. This one permits to compare the efficiency of stabilizer with dose rate or sample thickness.

  9. Spontaneous liposome formation induced by grafted poly(ethylene oxide) layers: Theoretical prediction and experimental verification

    OpenAIRE

    Szleifer, Igal; Gerasimov, Oleg V.; Thompson, David H.

    1998-01-01

    Spontaneous liposome formation is predicted in binary mixtures of fluid phase phospholipids and poly(n)ethylene oxide (PEO)-bearing lipids by using single chain mean field theory. The range of stability of the spontaneous liposomes is determined as a function of percentage of PEO-conjugated lipids and polymer molecular weight. These predictions were tested by using cast films of 1,2-diacyl-sn-glycerophosphocholines (e.g., egg l-α-lecithin, 1,2-dimyristoyl-sn-glycero-3-phosphocholine, 1,2-dipa...

  10. Preparation and solution behavior of a thermoresponsive diblock copolymer of poly(ethyl glycidyl ether) and poly(ethylene oxide).

    Science.gov (United States)

    Ogura, Michihiro; Tokuda, Hiroyuki; Imabayashi, Shin-ichiro; Watanabe, Masayoshi

    2007-08-28

    A thermoresponsive diblock copolymer, poly(ethyl glycidyl ether)-block-poly(ethylene oxide) (PEGE-b-PEO), is synthesized by successive anionic ring-opening polymerization of ethyl glycidyl ether and ethylene oxide using 2-phenoxyethanol as a starting material, and its solution behavior is elucidated in water. In a dilute 1 wt % solution, the temperature-dependent alteration in the polymer hydrodynamic radius (RH) is measured in the temperature range between 5 and 45 degrees C by pulse-gradient spin-echo NMR and dynamic light scattering. The RH value increased with temperature in two steps, where the first step at 15 degrees C corresponds to the core-shell micelle formation and the second step at 40 degrees C corresponds to the aggregation of the core-shell micelles. The formation of the core-shell micelles is supported by the solubilization of a dye (1,6-diphenyl-1,3,5-hexatriene) in the hydrophobic core, which is recognized for a copolymer solution in the temperature range between 20 and 40 degrees C. In this temperature range, the core-shell micelles and the unimers coexist and the fraction of the former gradually increases with increasing temperature, suggesting equilibrium between the micelles and the unimers. In the concentrated regime (40 wt % solution), the solution forms a gel and the small-angle X-ray scattering measurements reveal the successive formation of hexagonal and lamellar liquid crystal phases with increasing temperature.

  11. SYNTHESIS AND CHARACTERIZATION OF AMPHIPHILIC GRAFT COPOLYMER CONTAINING MICROPHASE SEPARATED AND LONG POLY(ETHYLENE OXIDE ) SIDE CHAIN STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    QIU Yongxing; YU Xiaojie; FENG Linxian; YANG Shilin

    1993-01-01

    Acryloyl terminated Poly (ethyleneoxide)macromonomers(PEO-A) with different PEO chain lengths have been prepared by deactivation of PEO alkoxide with acryloyl chloride. A new kind of amphiphilic polystyrene-g-poly (ethylene oxide)graft copolymer containing both microphase separated and PEO side chain structures has been synthesized from radical copolymerization of PEO-A macromonomer with styrene. After careful purification by a newly-developed method called "selective dissolution", the well-defined structure of the purified copolymers was confirmed by IR, 1H-NMR and GPC. Various experimental parameters controlling the copolymerization were studied in detail. The results indicated that the feed ratio of styrene to macromonomer(S/M) was the most important determining factor for the composition of the copolymers. A detailed "comb-model" was proposed to describe the molecular structure of the graft copolymers. Finally, this amphiphilic graft copolymers may readily form microphase separated structures as clearly indicated by transmission electron microscopy.

  12. Poly(ethylene oxide)-bonded stationary phase for separation of inorganic anions in capillary ion chromatography.

    Science.gov (United States)

    Linda, Roza; Lim, Lee Wah; Takeuchi, Toyohide

    2013-06-14

    A tosylated-poly(ethylene oxide) (PEO) reagent was reacted with primary amino groups of an aminopropylsilica packing material (TSKgel NH2-60) in acetonitrile to form PEO-bonded stationary phase. The reaction was a single and simple step reaction. The prepared stationary phase was able to separate inorganic anions. The retention behavior of six common inorganic anions on the prepared stationary phase was examined under various eluent conditions in order to clarify its separation/retention mechanism. The elution order of the tested anions was iodate, bromate, bromide, nitrate, iodide, and thiocyanate, which was similar as observed in common ion chromatography. The retention of inorganic anions could be manipulated by ion exchange interaction which is expected that the eluent cation is coordinated among the PEO chains and it works as the anion-exchange site. Cations and anions of the eluent therefore affected the retention of sample anions. We demonstrated that the retention of the analyte anions decreased with increasing eluent concentration. The repeatability of retention time for the six anions was satisfactory on this column with relative standard deviation values from 1.1 to 4.3% when 10mM sodium chloride was used as the eluent. Compared with the unmodified TSKgel NH2-60, the prepared stationary phase retained inorganic anions more strongly and the selectivity was also improved. The present stationary phase was applied for the determination of inorganic anions contained in various water samples.

  13. A bifunctional poly(ethylene glycol) silane immobilized on metallic oxide-based nanoparticles for conjugation with cell targeting agents

    Energy Technology Data Exchange (ETDEWEB)

    Kohler, Nathan J.; Fryxell, Glen E.; Zhang, Miqin

    2004-06-16

    A trifluoroethylester-terminal poly (ethylene glycol) (PEG) silane was synthesized and self-assembled on iron oxide nanoparticles. The nanoparticle system thus prepared has the flexibility to conjugate with cell targeting agents having either carboxylic and amine terminal groups for a number of biomedical applications, including magnetic resonance imaging (MRI) and controlled drug delivery. The trifluoroethylester silane was synthesized by modifying a PEG diacid to form the corresponding bistrifluoroethylester (TFEE), followed by a reaction with 3-aminopropyltriethoxysilane (APS). The APS coupled with PEG chains confers the stability of PEG self-assembled monolayers (SAMs) and increases the PEG packing density on nanoparticles by establishing hydrogen bonding between the carbonyl and amine groups present within the monolayer structure. The success of the synthesis of the PEG TEFE silane was confirmed with 1H NMR and Fourier transform infrared spectroscopy (FTIR). The conjugating flexibility of the PEG TEFE was demonstrated with folic acid having carboxylic acid groups and amine terminal groups respectively and confirmed by FTIR. TEM analysis showed the dispersion of nanoparticles before and after they were coated with PEG and folic acid.

  14. Electro-Mechanical Coupling of Indium Tin Oxide Coated Polyethylene Terephthalate ITO/PET for Flexible Solar Cells

    KAUST Repository

    Saleh, Mohamed A.

    2013-05-15

    Indium tin oxide (ITO) is the most widely used transparent electrode in flexible solar cells because of its high transparency and conductivity. But still, cracking of ITO on PET substrates due to tensile loading is not fully understood and it affects the functionality of the solar cell tremendously as ITO loses its conductivity. Here, we investigate the cracking evolution in ITO/PET exposed to two categories of tests. Monotonous tensile testing is done in order to trace the crack propagation in ITO coating as well as determining a loading range to focus on during our study. Five cycles test is also conducted to check the crack closure effect on the resistance variation of ITO. Analytical model for the damage in ITO layer is implemented using the homogenization concept as in laminated composites for transverse cracking. The homogenization technique is done twice on COMSOL to determine the mechanical and electrical degradation of ITO due to applied loading. Finally, this damage evolution is used for a simulation to predict the degradation of ITO as function in the applied load and correlate this degradation with the resistance variation. Experimental results showed that during unloading, crack closure results in recovery of conductivity and decrease in the overall resistance of the cracked ITO. Also, statistics about the crack spacing showed that the cracking pattern is not perfectly periodical however it has a positively skewed distribution. The higher the applied load, the less the discrepancy in the crack spacing data. It was found that the cracking mechanism of ITO starts with transverse cracking with local delamination at the crack tip unlike the mechanism proposed in the literature of having only cracking pattern without any local delamination. This is the actual mechanism that leads to the high increase in ITO resistance. The analytical code simulates the damage evolution in the ITO layer as function in the applied strain. This will be extended further to

  15. Multifunctional Photosensitizer Grafted on Polyethylene Glycol and Polyethylenimine Dual-Functionalized Nanographene Oxide for Cancer-Targeted Near-Infrared Imaging and Synergistic Phototherapy.

    Science.gov (United States)

    Luo, Shenglin; Yang, Zhangyou; Tan, Xu; Wang, Yang; Zeng, Yiping; Wang, Yu; Li, Changming; Li, Rong; Shi, Chunmeng

    2016-07-13

    The integration of photodynamic therapy (PDT) with photothermal therapy (PTT) offers improved efficacy in cancer phototherapy. Herein, a PDT photosensitizer (IR-808) with cancer-targeting ability and near-infrared (NIR) sensitivity was chemically conjugated to both polyethylene glycol (PEG)- and branched polyethylenimine (BPEI)-functionalized nanographene oxide (NGO). Because the optimal laser wavelength (808 nm) of NGO for PTT is consistent with that of IR-808 for PDT, the IR-808-conjugated NGO sheets (NGO-808, 20-50 nm) generated both large amounts of reactive oxygen species (ROS) and local hyperthermia as a result of 808 nm laser irradiation. With PEG- and BPEI-modified NGO as the carrier, the tumor cellular uptake of NGO-808 exhibited higher efficacy than that of strongly hydrophobic free IR-808. Through evaluation with both human and mouse cancer cells, NGO-808 was demonstrated to provide significantly enhanced PDT and PTT effects compared to individual PDT using IR-808 or PTT using NGO. Furthermore, NGO-808 preferentially accumulated in cancer cells as mediated by organic-anion transporting polypeptides (OATPs) overexpressed in many cancer cells, providing the potential for highly specific cancer phototherapy. Using the targeting ability of NGO-808, in vivo NIR fluorescence imaging enabled tumors and their margins to be clearly visualized at 48 h after intravenous injection, providing a theranostic platform for imaging-guided cancer phototherapy. Remarkably, after a single injection of NGO-808 and 808 nm laser irradiation for 5 min, the tumors in two tumor xenograft models were ablated completely, and no tumor recurrence was observed. After treatment with NGO-808, no obvious toxicity was detected in comparison to control groups. Thus, high-performance cancer phototherapy with minimal side effects was afforded from synergistic PDT/PTT treatment and cancer-targeted accumulation of NGO-808.

  16. In vitro and in vivo evaluation of a new nanocomposite, containing high density polyethylene, tricalcium phosphate, hydroxyapatite, and magnesium oxide nanoparticles.

    Science.gov (United States)

    Pourdanesh, Fereydoun; Jebali, Ali; Hekmatimoghaddam, Seyedhossein; Allaveisie, Azra

    2014-07-01

    In this study, a new nanocomposite, which contained high density polyethylene (HDPE), tricalcium phosphate (Ca3(PO4)2) nanoparticles (TCP NPs), hydroxyapatite nanoparticles (HA NPs), and magnesium oxide nanoparticles (MgO NPs) was prepared. As in vitro experiment, human osteoblasts (HOB) cells were exposed to pristine HDPE and its nanocomposite for a period of 1, 4, and 7 days at 37 °C, and then different assays were carried out, including osteoblast cell proliferation, Trypan blue staining, cell viability, alkaline phosphatase (ALP), and cell adhesion. Antibacterial property of pristine HDPE and its nanocomposite was evaluated, and also their mechanical properties were measured after 2 and 4 months. As in vivo experiment, pristine HDPE and its nanocomposite were separately implanted on calvarium bone of rabbits, and tissue inflammation and osteogenesis were investigated after 2, 4, and 6 months. In case of HOB cells treated with HDPE or nanocomposite, as incubation time was increased, cell proliferation, live/dead ratio, and cell viability were decreased. But, the ALP activity and cell adhesion of HOB cells which treated with nanocomposite were raised after increase of incubation time. This study demonstrated that although the mechanical properties of nanocomposite were similar to HDPE sheet, but their antibacterial property was not similar. The in vivo experiment showed that both pristine HDPE and its nanocomposite had same inflammation responses. Interestingly, osteogenesis was observed after 2 months at bone/nanocomposite interface, and was highly increased after 4 and 6 months. It must be noted that such pattern was not seen at bone/HDPE interface.

  17. In vitro and in vivo evaluation of a new nanocomposite, containing high density polyethylene, tricalcium phosphate, hydroxyapatite, and magnesium oxide nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Pourdanesh, Fereydoun [Dental Research Center, Research Institute of Dental Sciences, Shahid Beheshti University of Medical Sciences, Tehran 8916733754 (Iran, Islamic Republic of); Jebali, Ali, E-mail: alijebal2011@gmail.com [Department of Medical Physics and Biomedical Engineering, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Hekmatimoghaddam, Seyedhossein [Department of Laboratory Sciences, School of Paramedicine, Shahid Sadoughi University of Medical Sciences, Yazd (Iran, Islamic Republic of); Allaveisie, Azra [Department of Genetics, Research and Clinical Center for Infertility, Shahid Sadoughi University of Medical Sciences, Yazd (Iran, Islamic Republic of)

    2014-07-01

    In this study, a new nanocomposite, which contained high density polyethylene (HDPE), tricalcium phosphate (Ca{sub 3}(PO{sub 4}){sub 2}) nanoparticles (TCP NPs), hydroxyapatite nanoparticles (HA NPs), and magnesium oxide nanoparticles (MgO NPs) was prepared. As in vitro experiment, human osteoblasts (HOB) cells were exposed to pristine HDPE and its nanocomposite for a period of 1, 4, and 7 days at 37 °C, and then different assays were carried out, including osteoblast cell proliferation, Trypan blue staining, cell viability, alkaline phosphatase (ALP), and cell adhesion. Antibacterial property of pristine HDPE and its nanocomposite was evaluated, and also their mechanical properties were measured after 2 and 4 months. As in vivo experiment, pristine HDPE and its nanocomposite were separately implanted on calvarium bone of rabbits, and tissue inflammation and osteogenesis were investigated after 2, 4, and 6 months. In case of HOB cells treated with HDPE or nanocomposite, as incubation time was increased, cell proliferation, live/dead ratio, and cell viability were decreased. But, the ALP activity and cell adhesion of HOB cells which treated with nanocomposite were raised after increase of incubation time. This study demonstrated that although the mechanical properties of nanocomposite were similar to HDPE sheet, but their antibacterial property was not similar. The in vivo experiment showed that both pristine HDPE and its nanocomposite had same inflammation responses. Interestingly, osteogenesis was observed after 2 months at bone/nanocomposite interface, and was highly increased after 4 and 6 months. It must be noted that such pattern was not seen at bone/HDPE interface. - Highlights: • The effect of various nanoparticles like as Ca{sub 3}(PO{sub 4}){sub 2}, hydroxyapatite, and MgO was studied. • HDPE/TCP/HA/MgO nanocomposite was biocompatible. • The effect of nanoparticles showed high antibacterial property.

  18. Preparation and Property Evaluation of Conductive Hydrogel Using Poly (Vinyl Alcohol/Polyethylene Glycol/Graphene Oxide for Human Electrocardiogram Acquisition

    Directory of Open Access Journals (Sweden)

    Xueliang Xiao

    2017-06-01

    Full Text Available Conductive hydrogel combined with Ag/AgCl electrode is widely used in the acquisition of bio-signals. However, the high adhesiveness of current commercial hydrogel causes human skin allergies and pruritus easily after wearing hydrogel for electrodes for a long time. In this paper, a novel conductive hydrogel with good mechanical and conductive performance was prepared using polyvinyl alcohol (PVA, polyethylene glycol (PEG, and graphene oxide (GO nanoparticles. A cyclic freezing–thawing method was employed under processing conditions of −40 °C (8 h and 20 °C (4 h separately for three cycles in sequence until a strong conductive hydrogel, namely, PVA/PEG/GO gel, was obtained. Characterization (Fourier transform infrared spectroscopy, nuclear magnetic resonance, scanning electron microscopy results indicated that the assembled hydrogel was successfully prepared with a three-dimensional network structure and, thereafter, the high strength and elasticity due to the complete polymeric net formed by dense hydrogen bonds in the freezing process. The as-made PVA/PEG/GO hydrogel was then composited with nonwoven fabric for electrocardiogram (ECG electrodes. The ECG acquisition data indicated that the prepared hydrogel has good electro-conductivity and can obtain stable ECG signals for humans in a static state and in motion (with a small amount of drift. A comparison of results indicated that the prepared PVA/PEG/GO gel obtained the same quality of ECG signals with commercial conductive gel with fewer cases of allergies and pruritus in volunteer after six hours of wear.

  19. Highly CO2-Selective Gas Separation Membranes Based on Segmented Copolymers of Poly(Ethylene oxide) Reinforced with Pentiptycene-Containing Polyimide Hard Segments.

    Science.gov (United States)

    Luo, Shuangjiang; Stevens, Kevin A; Park, Jae Sung; Moon, Joshua D; Liu, Qiang; Freeman, Benny D; Guo, Ruilan

    2016-01-27

    Poly(ethylene oxide) (PEO)-containing polymer membranes are attractive for CO2-related gas separations due to their high selectivity toward CO2. However, the development of PEO-rich membranes is frequently challenged by weak mechanical properties and a high crystallization tendency of PEO that hinders gas transport. Here we report a new series of highly CO2-selective, amorphous PEO-containing segmented copolymers prepared from commercial Jeffamine polyetheramines and pentiptycene-based polyimide. The copolymers are much more mechanically robust than the nonpentiptycene containing counterparts due to the molecular reinforcement mechanism of supramolecular chain threading and interlocking interactions induced by the pentiptycene structures, which also effectively suppresses PEO crystallization leading to a completely amorphous structure even at 60% PEO weight content. Membrane transport properties are sensitively affected by both PEO weight content and PEO chain length. A nonlinear correlation between CO2 permeability with PEO weight content was observed due to the competition between solubility and diffusivity contributions, whereby the copolymers change from being size-selective to solubility-selective when PEO content reaches 40%. CO2 selectivities over H2 and N2 increase monotonically with both PEO content and chain length, indicating strong CO2-philicity of the copolymers. The copolymer film with the longest PEO sequence (PEO2000) and highest PEO weight content (60%) showed a measured CO2 pure gas permeability of 39 Barrer, and ideal CO2/H2 and CO2/N2 selectivities of 4.1 and 46, respectively, at 35 °C and 3 atm, making them attractive for hydrogen purification and carbon capture.

  20. Conformational sensitivity of conjugated poly(ethylene oxide)-poly(amidoamine) molecules to cations adducted upon electrospray ionization – A mass spectrometry, ion mobility and molecular modeling study

    Energy Technology Data Exchange (ETDEWEB)

    Tintaru, Aura [Aix-Marseille Université – CNRS, UMR 7273, Institut de Chimie Radicalaire, Marseille (France); Chendo, Christophe [Aix-Marseille Université – CNRS, FR 1739, Fédération des Sciences Chimiques de Marseille, Spectropole, Marseille (France); Wang, Qi [Aix-Marseille Université – CNRS, UMR 6114, Centre Interdisciplinaire de Nanosciences de Marseille, Marseille (France); Viel, Stéphane [Aix-Marseille Université – CNRS, UMR 7273, Institut de Chimie Radicalaire, Marseille (France); Quéléver, Gilles; Peng, Ling [Aix-Marseille Université – CNRS, UMR 6114, Centre Interdisciplinaire de Nanosciences de Marseille, Marseille (France); Posocco, Paola [University of Trieste, Molecular Simulation Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), Trieste (Italy); National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Trieste (Italy); Pricl, Sabrina, E-mail: sabrina.pricl@di3.units.it [University of Trieste, Molecular Simulation Engineering (MOSE) Laboratory, Department of Engineering and Architecture (DEA), Trieste (Italy); National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE-DEA, University of Trieste, Trieste (Italy); Charles, Laurence, E-mail: laurence.charles@univ-amu.fr [Aix-Marseille Université – CNRS, UMR 7273, Institut de Chimie Radicalaire, Marseille (France)

    2014-01-15

    Graphical abstract: -- Highlights: •ESI-MS/MS, IMS and molecular modeling were combined to study PEO-PAMAM conformation. •Protonated and lithiated molecules were studied, with charge states from 2 to 4. •Protonation mostly occurred on PAMAM, with PEO units enclosing the protonated group. •Lithium adduction on PEO units lead to more expanded conformations. •Charge location strongly influenced PEO-PAMAM dissociation behavior. -- Abstract: Tandem mass spectrometry and ion mobility spectrometry experiments were performed on multiply charged molecules formed upon conjugation of a poly(amidoamine) (PAMAM) dendrimer with a poly(ethylene oxide) (PEO) linear polymer to evidence any conformational modification as a function of their charge state (2+ to 4+) and of the adducted cation (H{sup +}vs Li{sup +}). Experimental findings were rationalized by molecular dynamics simulations. The G0 PAMAM head-group could accommodate up to three protons, with protonated terminal amine group enclosed in a pseudo 18-crown-6 ring formed by the PEO segment. This particular conformation enabled a hydrogen bond network which allowed long-range proton transfer to occur during collisionally activated dissociation. In contrast, lithium adduction was found to mainly occur onto oxygen atoms of the polyether, each Li{sup +} cation being coordinated by a 12-crown-4 pseudo structure. As a result, for the studied polymeric segment (M{sub n} = 1500 g mol{sup −1}), PEO-PAMAM hybrid molecules exhibited a more expanded shape when adducted to lithium as compared to proton.

  1. In vitro and in vivo experiments with iron oxide nanoparticles functionalized with DEXTRAN or polyethylene glycol for medical applications: magnetic targeting.

    Science.gov (United States)

    Mojica Pisciotti, M L; Lima, E; Vasquez Mansilla, M; Tognoli, V E; Troiani, H E; Pasa, A A; Creczynski-Pasa, T B; Silva, A H; Gurman, P; Colombo, L; Goya, G F; Lamagna, A; Zysler, R D

    2014-05-01

    In this research work, DEXTRAN- and polyethylene glycol (PEG)-coated iron-oxide superparamagnetic nanoparticles were synthetized and their cytotoxicity and biodistribution assessed. Well-crystalline hydrophobic Fe3 O4 SPIONs were formed by a thermal decomposition process with d = 18 nm and σ = 2 nm; finally, the character of SPIONs was changed to hydrophilic by a post-synthesis procedure with the functionalization of the SPIONs with PEG or DEXTRAN. The nanoparticles present high saturation magnetization and superparamagnetic behavior at room temperature, and the hydrodynamic diameters of DEXTRAN- and PEG-coated SPIONs were measured as 170 and 120 nm, respectively. PEG- and DEXTRAN-coated SPIONs have a Specific Power Absorption SPA of 320 and 400 W/g, respectively, in an ac magnetic field with amplitude of 13 kA/m and frequency of 256 kHz. In vitro studies using VERO and MDCK cell lineages were performed to study the cytotoxicity and cell uptake of the SPIONs. For both cell lineages, PEG- and DEXTRAN-coated nanoparticles presented high cell viability for concentrations as high as 200 μg/mL. In vivo studies were conducted using BALB/c mice inoculating the SPIONs intravenously and exposing them to the presence of an external magnet located over the tumour. It was observed that the amount of PEG-coated SPIONs in the tumor increased by up to 160% when using the external permanent magnetic as opposed to those animals that were not exposed to the external magnetic field.

  2. 高密度聚乙烯土工格栅光氧老化研究进展%Progress of Study on Photo-oxidation Aging of High Density Polyethylene Geogrids

    Institute of Scientific and Technical Information of China (English)

    蒋秀亭; 杨旭东; 童军

    2015-01-01

    对高密度聚乙烯( HDPE)土工格栅的光氧老化机理进行系统性的介绍;分析影响土工格栅光氧老化的外界因素,包括环境因素、安装损耗和加工方式等;同时介绍高密度聚乙烯土工格栅降解后性能的变化,从力学性能、外观变化及微观指标三方面总结其老化后的表征指标,并指出HDPE土工格栅光氧老化研究方面的不足。%In this paper,the mechanisms of High density polyethylene( HDPE) geogrids after photo-oxidation ag-ing are introduced systematically. Analyzed the influence factors for geogrids during photo-oxidation degradation,in-cluding environment factors,installation damages and processing methods. Simultaneously,introduced performance changes in the photo-oxidation of high density polyethylene geogrids,and summarized characterization of indicators from the mechanical properties,changes in appearance and microstructure indicators. Also pointed out deficiency at aspects of research and future research issues are analyzed for HDPE geogrids.

  3. Solid State Nuclear Magnetic Resonance Investigation of Polymer Backbone Dynamics in Poly(Ethylene Oxide) Based Lithium and Sodium Polyether-ester-sulfonate Ionomers

    Energy Technology Data Exchange (ETDEWEB)

    Roach, David J.; Dou, Shichen; Colby, Ralph H.; Mueller, Karl T.

    2013-01-01

    Polymer backbone dynamics of single ion conducting poly(ethylene oxide) (PEO)-based ionomer samples with low glass transition temperatures (Tg) have been investigated using solid-state nuclear magnetic resonance (NMR). Experiments detecting 13C with 1H decoupling under magic angle spinning (MAS) conditions identified the different components of the polymer backbone (PEO spacer and isophthalate groups) and their relative mobilities for a suite of lithium- and sodium-containing ionomer samples with varying cation contents. Variable temperature (203-373 K) 1H-13C cross-polarization MAS (CP-MAS) experiments also provided qualitative assessment of the differences in the motions of the polymer backbone components as a function of cation content and identity. Each of the main backbone components exhibit distinct motions, following the trends expected for motional characteristics based on earlier Quasi Elastic Neutron Scattering and 1H spin-lattice relaxation rate measurements. Previous 1H and 7Li spin-lattice relaxation measurements focused on both the polymer backbone and cation motion on the nanosecond timescale. The studies presented here assess the slower timescale motion of the polymer backbone allowing for a more comprehensive understanding of the polymer dynamics. The temperature dependences of 13C linewidths were used to both qualitatively and quantitatively examine the effects of cation content and identity on PEO spacer mobility. Variable contact time 1H-13C CP-MAS experiments were used to further assess the motions of the polymer backbone on the microsecond timescale. The motion of the PEO spacer, reported via the rate of magnetization transfer from 1H to 13C nuclei, becomes similar for T ≳ 1.1 Tg in all ionic samples, indicating that at similar elevated reduced temperatures the motions of the polymer backbones on the microsecond timescale become insensitive to ion interactions. These results present an improved picture, beyond those of previous findings, for

  4. Properties and mechanisms of drug release from matrix tablets containing poly(ethylene oxide) and poly(acrylic acid) as release retardants.

    Science.gov (United States)

    Zhang, Feng; Meng, Fan; Lubach, Joseph; Koleng, Joseph; Watson, N A

    2016-08-01

    The interactions between poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) in aqueous medium at pH 6.8 were investigated in the current study. We have also studied the effect of interpolymer interactions and various formulation variables, including the molecular weight of PEO, the ratio between PEO and PAA, the crystallinity of PEO, and the presence of an acidifying agent, on the release of theophylline from matrix tablets containing both PEO and PAA as release retardants. At pH 6.8, the synergy in solution viscosity between PEO and PAA as the result of ion-dipole interaction was observed in this study. The release of theophylline from the matrix tablets containing physical mixtures of PEO and PAA was found to be a function of dissolution medium pH because of the pH-dependent interactions between these two polymers. Because of the formation of water insoluble interpolymer complex between PEO and PAA in aqueous medium at pH below 4.0, the release of theophylline was independent of PEO molecular weight and was controlled by Fickian diffusion mechanism in 0.01N hydrochloric acid solution. In comparison, the drug release was a function of PEO molecular weight and followed the anomalous transport mechanism in phosphate buffer pH 6.8. The presence of PAA exerted opposite effects on the release of theophylline in phosphate buffer pH 6.8. In one aspect, theophylline release was accelerated because the erosion of PAA was much faster than that of PEO at pH6.8. On the opposite aspect, theophylline release was slowed down because of the formation of insoluble complex inside the gel layer as the result of the acidic microenvironment induced by PAA, and the increase in the viscosity of the gel layer as the result of the synergy between PEO and PAA. These two opposite effects offset each other. As a result, the release of theophylline remained statistically the same even when 75% PEO in the formulation was replaced with PAA. In phosphate buffer pH 6.8, the release of

  5. 等离子体类聚氧乙烯薄膜的制备及性能研究%Fabrication and properties of plasma polyethylene oxide

    Institute of Scientific and Technical Information of China (English)

    陈瑞; 刘玉洁; 李欣; 王进; 孙鸿; 黄楠

    2013-01-01

    等离子体类聚氧乙烯薄膜(PEO-like)具有高亲水性、抗生物粘附的特性,能被应用于生物材料表面改性以提高材料的抗蛋白粘附、抗血小板粘附和抗菌等性能。以四乙二醇二甲醚(tetraethylene glycol dimethyl ether)为单体,采用射频等离子体连续放电模式,不锈钢 SS 为基底,在不同功率下合成了 PEO-like薄膜。傅里叶变换红外光谱仪(FT-IR)、X光电子能谱仪(XPS)测试分析表明等离子体 PEO-like 薄膜中能部分保留单体分子中的氧化乙烯(EO)结构单元,功率为5 W合成的 PEO-like 薄膜中 EO 单元含量为35.86%。PEO-like 薄膜的亲水性优于不锈钢,薄膜在双蒸水中浸没1和10d 的结果显示,尽管薄膜出现溶胀现象,但没有剥落和破裂。低功率下合成的薄膜具有一定的阻抗血小板粘附的性能,但3d的体外平滑肌细胞评价结果表明,3种 PEO-like 薄膜没有表现出抑制平滑肌细胞增殖的性能。%The polyethylene oxide like (PEO-like)film prepared by plasma polymerization has high hydrophilici-ty and anti-bioadhesion,which can be used to modify the biomaterial surface to improve the inhibition of protein adhesion,platelet adhesion and anti-bacterial adhesion.The PEO-like films on stainless steel (SS)substrates were prepared by radio frequency plasma polymerization technique with tetraethylene glycol dimethyl ether (EGDME)as the precursor.The results of Fourier transform infrared spectroscopy (FT-IR)and X-ray photoe-lectron spectroscopy (XPS)showed that the PEO-like film could keep part of ethylene oxide unit,and especial-ly the EO content of PP-PEO-1 film fabricated under 5W power was 35.86%.Compared to the SS,there was more hydrophilic for the PEO-like films.The PEO-like films exhibited the swollen stripes,but the spalling and rupture could not be found.The PEO-like film prepared under 5W and 10W had certain properties to prohibit the adhesion of platelet.But the evaluation of in vitro smooth muscle

  6. A polymer gel electrolyte composed of a poly(ethylene oxide) copolymer and the influence of its composition on the dynamics and performance of dye-sensitized solar cells

    Science.gov (United States)

    Benedetti, João E.; Gonçalves, Agnaldo D.; Formiga, André L. B.; De Paoli, Marco-A.; Li, X.; Durrant, James R.; Nogueira, Ana F.

    A polymer gel electrolyte composed of a poly(ethylene oxide) derivative, poly(ethylene oxide-co-2-(2-methoxyethoxy) ethyl glycidyl ether), mixed with gamma-butyrolactone (GBL), LiI and I 2 is employed in dye sensitized solar cells (DSSC). The electrolyte is characterized by conductivity experiments, Raman spectroscopy and thermal analysis. The influence of the electrolyte composition on the kinetics of DSSC is also investigated by transient absorption spectroscopy (TAS). The electrolyte containing 70 wt.% of GBL and 20 wt.% of LiI presents the highest conductivity (1.9 × 10 -3 S cm -1). An efficiency of 4.4% is achieved using this composition. The increase in I SC as a function of GBL can be attributed an increase in the mobility of the iodide (polyiodide) species. The increase in the yield of the intermediate species, I 2 -, originating in the regeneration reaction, is confirmed by TAS. However, the charge recombination process is faster at this composition and a decrease in the V oc is observed. Photovoltage decay experiments confirm an acceleration in charge recombination for the DSSC assembled with the electrolyte containing more GBL. Raman investigations show that in this electrolyte the I 5 -/I 3 - ratio is higher. Theoretical calculations also indicate that the I 5 - species is a better electron acceptor.

  7. A polymer gel electrolyte composed of a poly(ethylene oxide) copolymer and the influence of its composition on the dynamics and performance of dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Benedetti, Joao E.; Goncalves, Agnaldo D.; Formiga, Andre L.B.; De Paoli, Marco-A.; Nogueira, Ana F. [Institute of Chemistry, University of Campinas - UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP (Brazil); Li, X.; Durrant, James R. [Centre for Electronic Materials and Devices, Imperial College of Science Technology and Medicine, London SW7 2AY (United Kingdom)

    2010-02-15

    A polymer gel electrolyte composed of a poly(ethylene oxide) derivative, poly(ethylene oxide-co-2-(2-methoxyethoxy) ethyl glycidyl ether), mixed with gamma-butyrolactone (GBL), LiI and I{sub 2} is employed in dye sensitized solar cells (DSSC). The electrolyte is characterized by conductivity experiments, Raman spectroscopy and thermal analysis. The influence of the electrolyte composition on the kinetics of DSSC is also investigated by transient absorption spectroscopy (TAS). The electrolyte containing 70 wt.% of GBL and 20 wt.% of LiI presents the highest conductivity (1.9 x 10{sup -3} S cm{sup -1}). An efficiency of 4.4% is achieved using this composition. The increase in I{sub SC} as a function of GBL can be attributed an increase in the mobility of the iodide (polyiodide) species. The increase in the yield of the intermediate species, I{sub 2}{sup -}, originating in the regeneration reaction, is confirmed by TAS. However, the charge recombination process is faster at this composition and a decrease in the V{sub oc} is observed. Photovoltage decay experiments confirm an acceleration in charge recombination for the DSSC assembled with the electrolyte containing more GBL. Raman investigations show that in this electrolyte the I{sub 5}{sup -}/I{sub 3}{sup -} ratio is higher. Theoretical calculations also indicate that the I{sub 5}{sup -} species is a better electron acceptor. (author)

  8. Blends of POSS-PEO(n=4)(8) and high molecular weight poly(ethylene oxide) as solid polymer electrolytes for lithium batteries.

    Science.gov (United States)

    Zhang, Hanjun; Kulkarni, Sunil; Wunder, Stephanie L

    2007-04-12

    Solid polymer electrolyte blends were prepared with POSS-PEO(n=4)8 (3K), poly(ethylene oxide) (PEO(600K)), and LiClO4 at different salt concentrations (O/Li = 8/1, 12/1, and 16/1). POSS-PEO(n=4)8/LiClO4 is amorphous at all O/Li investigated, whereas PEO(600K) is amorphous only for O/Li = 8/1 and semicrystalline for O/Li = 12/1 and 16/1. The tendency of PEO(600K) to crystallize limited the amount of POSS-PEO(n=4)(8) that could be incorporated into the blends, so that the greatest incorporation of POSS-PEO(n=4)(8) occurred for O/Li = 8/1. Blends of POSS-PEO(n=4)(8)/PEO(600K)/LiClO4 (O/Li = 8/1 and 12/1) microphase separated into two amorphous phases, a low T(g) phase of composition 85% POSS-PEO(n=4)(8)/15% PEO(600K) and a high T(g) phase of composition 29% POSS-PEO(n=4)(8)/71% PEO(600K). For O/Li = 16/1, the blends contained crystalline (pure PEO(600K)), and two amorphous phases, one rich in POSS-PEO(n=4)(8) and one rich in PEO(600K). Microphase, rather than macrophase separation was believed to occur as a result of Li(+)/ether oxygen cross-link sites. The conductivity of the blends depended on their composition. As expected, crystallinity decreased the conductivity of the blends. For the amorphous blends, when the low T(g) (80/20) phase was the continuous phase, the conductivity was intermediate between that of pure PEO(600K) and POSS-PEO(n=4)(8). When the high T(g) (70/30, 50/50, 30/70, and 20/80) phase was the continuous phase, the conductivity of the blend and PEO(600K) were identical, and lower than that for the POSS-PEO(n=4)(8) over the whole temperature range (10-90 degrees C). This suggests that the motions of the POSS-PEO(n=4)(8) were slowed down by the dynamics of the long chain PEO(600K) and that the minor, low Tg phase was not interconnected and thus did not contribute to enhanced conductivity. At temperatures above T(m) of PEO(600K), addition of the POSS-PEO(n=4)(8) did not result in conductivity improvement. The highest RT conductivity, 8 x 10(-6) S

  9. Radiation resistivity of polyacenaphthylene-grafted polyethylene

    Science.gov (United States)

    Hayakawa, Kiyoshi; Kawase, Kaoru; Yamakita, Hiromi

    Thin poly (ethylene-g-acenaphthylene) films prepared by the vapor-phase grafting method were subjected to the γ-irradiation in air, and various changes in tensile and structural properties of the film were investigated by comparing with those of the untreated or crosslinked polyethylene film. Polyethylene got to lose its inherent necking property by oxidative degradation and to be brittle-fractured by the irradiation dose less than 100 Mrad in air. The polyacenaphthylene-grafted polyethylenes (extent of grafting, ˜ 54 by {100( P-P°) }/{P°}), however, kept their ductility up to 200 Mrad or more, and the rate of increase in elastic modulus as well as yield strength with the increasing irradiation dose was considerably lower than that of untreated or crosslinked polyethylene. The effect of the grafting extent, and that of the irradiation dose-rate on the fracture energy were also examined. The weight increase of polyethylene due to the oxygen consumption and the resulting formation of carbonyl group which proceeded proportionally with the irradiation dose were remarkably suppressed by the grafting, whereas the double bond formation seemed to be unaffected by it. The grafted film held the original content of gel fraction unchanged during the irradiation in air, but the average molecular weight of the sol fraction decreased gradually. Meanwhile, the gel fraction of the crosslinked polyethylene was degenerated by a small dose of irradiation. The analysis of gaseous products revealed the formation of water, methanol, acetaldehyde and so forth from the irradiated grafted film. The grafting procedure and the subsequent irradiation of the grafted film did not affect the degree of crystallinity of the backbone polyethylene. The role played by the grafted polyacenaphthylene for endowing the radiation resistivity to polyethylene and its inherent limitation in effect were discussed from the structural point of view of the grafted film.

  10. Hybrid inorganic-organic materials: Novel poly(propylene oxide)-based ceramers, abrasion-resistant sol-gel coatings for metals, and epoxy-clay nanocomposites, with an additional chapter on: Metallocene-catalyzed linear polyethylene

    Science.gov (United States)

    Jordens, Kurt

    1999-12-01

    The sol-gel process has been employed to generate hybrid inorganic-organic network materials. Unique ceramers were prepared based on an alkoxysilane functionalized soft organic oligomer, poly(propylene oxide (PPO), and tetramethoxysilane (TMOS). Despite the formation of covalent bonds between the inorganic and organic constituents, the resulting network materials were phase separated, composed of a silicate rich phase embedded in a matrix of the organic oligomer chains. The behavior of such materials was similar to elastomers containing a reinforcing filler. The study focused on the influence of initial oligomer molecular weight, functionality, and tetramethoxysilane, water, and acid catalyst content on the final structure, mechanical and thermal properties. The sol-gel approach has also been exploited to generate thin, transparent, abrasion resistant coatings for metal substrates. These systems were based on alkoxysilane functionalized diethylenetriamine (DETA) with TMOS, which generated hybrid networks with very high crosslink densities. These materials were applied with great success as abrasion resistant coatings to aluminum, copper, brass, and stainless steel. In another study, intercalated polymer-clay nanocomposites were prepared based on various epoxy networks montmorillonite clay. This work explored the influence of incorporated clay on the adhesive properties of the epoxies. The lap shear strength decreased with increasing day content This was due to a reduction in the toughness of the epoxy. Also, the delaminated (or exfoliated) nanocomposite structure could not be generated. Instead, all nanocomposite systems possessed an intercalated structure. The final project involved the characterization of a series of metallocene catalyzed linear polyethylenes, produced at Phillips Petroleum. Polyolefins synthesized with such new catalyst systems are becoming widely available. The influence of molecular weight and thermal treatment on the mechanical, rheological

  11. [Biodegradation of polyethylene].

    Science.gov (United States)

    Yang, Jun; Song, Yi-ling; Qin, Xiao-yan

    2007-05-01

    Plastic material is one of the most serious solid wastes pollution. More than 40 million tons of plastics produced each year are discarded into environment. Plastics accumulated in the environment is highly resistant to biodegradation and not be able to take part in substance recycle. To increase the biodegradation efficiency of plastics by different means is the main research direction. This article reviewed the recent research works of polyethylene biodegradation that included the modification and pretreatment of polyethylene, biodegradation pathway, the relevant microbes and enzymes and the changes of physical, chemical and biological properties after biodegradation. The study directions of exploiting the kinds of life-forms of biodegradation polyethylene except the microorganisms, isolating and cloning the key enzymes and gene that could produce active groups, and enhancing the study on polyethylene biodegradation without additive were proposed.

  12. Enhancement of ionic conductivity of composite membranes for all-solid-state lithium rechargeable batteries incorporating tetragonal Li7La3Zr2O12 into a polyethylene oxide matrix

    Science.gov (United States)

    Choi, Jeong-Hee; Lee, Chul-Ho; Yu, Ji-Hyun; Doh, Chil-Hoon; Lee, Sang-Min

    2015-01-01

    The lithium ion conductivities of as-prepared composite membranes consisting of a polyethylene oxide (PEO) matrix with various contents of tetragonal Li7La3Zr2O12 (LLZO) were evaluated, and the optimum composition (52.5% LLZO) was determined by performing AC impedance measurements. The ionic conductivities of the composite membranes pass through a maximum as the LLZO content varies. Therefore, the hybridization of the organic and inorganic components of these membranes results in synergetic effects on their lithium ionic conductivity. In addition, tests of Li/composite membrane/LiNi0.6Co0.2Mn0.2O2 half-cells found that their charge/discharge properties are better than those of a PEO-only membrane and a membrane containing 52.5% Al2O3 instead of LLZO.

  13. Anti-oxidation treatment of ultra high molecular weight polyethylene components to decrease periprosthetic osteolysis: evaluation of osteolytic and osteogenic properties of wear debris particles in a murine calvaria model.

    Science.gov (United States)

    Green, Justin M; Hallab, Nadim J; Liao, Yen-Shuo; Narayan, Venkat; Schwarz, Edward M; Xie, Chao

    2013-05-01

    Wear debris-induced osteolysis remains the greatest limitation of long-term success for total joint replacements with ultra-high molecular weight polyethylene (UHMWPE) bearings. To address oxidative degradation post-gamma irradiation, manufacturers are investigating the incorporation of antioxidants into PE resins. Similarly, larger molecular weight monomers have been developed to increase crosslinking and decrease wear debris, and ultimately osteolysis. However, the effects of modifying monomer size, crosslink density, and antioxidant incorporation on UHMWPE particle-induced osteoclastic bone resorption and coupled osteoblastic bone formation have never been tested. Here, we review the field of antioxidant-containing UHMWPE, and present an illustrative pilot study evaluating the osteolytic and osteogenic potential of wear debris generated from three chemically distinct particles (MARATHON®, XLK, and AOX™) as determined by a novel 3D micro-CT algorithm designed for the murine calvaria model. The results demonstrate an approach by which the potential osteoprotective effects of antioxidants in UHMWPE can be evaluated.

  14. Ionic conductivity and interfacial properties of nanochitin-incorporated polyethylene oxide-LiN(C{sub 2}F{sub 5}SO{sub 2}){sub 2} polymer electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Angulakshmi, N.; Prem Kumar, T. [Electrochemical Power Systems Division, Central Electrochemical Research Institute, Karaikudi 630006 (India); Thomas, Sabu [School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686560 (India); Manuel Stephan, A., E-mail: arulmanuel@gmail.co [Electrochemical Power Systems Division, Central Electrochemical Research Institute, Karaikudi 630006 (India)

    2010-01-25

    Nanocomposite polymer electrolytes (NCPE) composed of poly(ethylene oxide) and nanochitin for different concentrations of LiN(C{sub 2}F{sub 5}SO{sub 2}){sub 2} (LiBETI) were prepared by a completely dry, solvent-free procedure using a hot press. The thermal stability of NCPE membranes was investigated by DSC and TG-DTA. The membranes were subjected to SEM, ionic conductivity and FTIR analysis. Li/NCPE/Li symmetric cells were assembled and the variation of interfacial resistance as a function of time was also measured. The surface chemistry of lithium electrodes in contact with NCPE revealed the formation of Li-O-C and LiN compounds. LiFePO{sub 4}/NCPE/Li cell was assembled and the cycling profile showed a well-defined and reproducible shape of the voltage curves thus indicating a good cycling behavior of the cell at 60 deg. C.

  15. Preparation of liquid-core nanocapsules from poly[(ethylene oxide)-co-glycidol] with multiple hydrophobic linoleates at an oil-water interface and its encapsulation of pyrene.

    Science.gov (United States)

    Ren, Yong; Wang, Guowei; Huang, Junlian

    2007-06-01

    A convenient approach is provided to prepare liquid-core nanocapsules by cross-linking an amphiphilic copolymer at an oil-water interface. The hydrophilic copolymer poly[(ethylene oxide)-co-glycidol] was prepared by anionic polymerization of ethylene oxide and ethoxyethyl glycidyl ether first, then the hydroxyl groups on the backbone were recovered after hydrolysis and partly modified by hydrophobic conjugated linoleic acid. The copolymer with multiple linoleate pendants was absorbed at an oil-water interface and then cross-linked to form stable nanocapsules. The mean diameter of the nanocapsule was below 350 nm, and the size distribution was relatively narrow (<0.2) at low concentrations of oil in acetone (<10 mg/mL). The particle size could be tuned easily by variation of the emulsification conditions. The nanocapsule was stable in water for at least 5 months, and the shell maintained its integrity after removal of the oily core by solvent. Pyrene was encapsulated in these nanocapsules, and a loading efficiency as high as 94% was measured by UV spectroscopy.

  16. Polyethylene Glycols as Efficient Catalysts for the Oxidation of Xanthine Alkaloids by Ceric Ammonium Nitrate in Acetonitrile: A Kinetic and Mechanistic Approach

    Directory of Open Access Journals (Sweden)

    S. Shylaja

    2013-01-01

    Full Text Available Kinetics of oxidation of xanthine alkaloids, such as Xanthine (XAN, hypoxanthine (HXAN, caffeine (CAF, theophylline (TPL, and theobromine (TBR, have been studied with ceric ammonium nitrate (CAN using poly ethylene glycols (PEG as catalysts. Reaction obeyed first order kinetics in both [CAN] and [Xanthine alkaloid]. Highly sluggish CAN-xanthine alkaloid reactions (in acetonitrile media even at elevated temperatures are enhanced in presence PEGs (PEG-200, -300, -400, -600. An increase in [PEG] increased the rate of oxidation linearly. This observation coupled with a change in absorption of CAN in presence of PEG, [H–(OCH2–CH2n–O–NH4Ce(NO34(CH3CN] (PEG bound CAN species, is considered to be more reactive than CAN. The mechanism of oxidation in PEG media has been explained by Menger-Portnoy’s enzymatic model.

  17. Polyethylene glycol-coated graphene oxide attenuates antigen-specific IgE production and enhanced antigen-induced T-cell reactivity in ovalbumin-sensitized BALB/c mice.

    Science.gov (United States)

    Wu, Hsin-Ying; Lin, Kun-Ju; Wang, Ping-Yen; Lin, Chi-Wen; Yang, Hong-Wei; Ma, Chen-Chi M; Lu, Yu-Jen; Jan, Tong-Rong

    2014-01-01

    Graphene oxide (GO) is a promising nanomaterial for potential application in the versatile field of biomedicine. Graphene-based nanomaterials have been reported to modulate the functionality of immune cells in culture and to induce pulmonary inflammation in mice. Evidence pertaining to the interaction between graphene-based nanomaterials and the immune system in vivo remains scarce. The present study investigated the effect of polyethylene glycol-coated GO (PEG-GO) on antigen-specific immunity in vivo. BALB/c mice were intravenously administered with a single dose of PEG-GO (0.5 or 1 mg/kg) 1 hour before ovalbumin (OVA) sensitization, and antigen-specific antibody production and splenocyte reactivity were measured 7 days later. Exposure to PEG-GO significantly attenuated the serum level of OVA-specific immunoglobulin E. The production of interferon-γ and interleukin-4 by splenocytes restimulated with OVA in culture was enhanced by treatment with PEG-GO. In addition, PEG-GO augmented the metabolic activity of splenocytes restimulated with OVA but not with the T-cell mitogen concanavalin A. Collectively, these results demonstrate that systemic exposure to PEG-GO modulates several aspects of antigen-specific immune responses, including the serum production of immunoglobulin E and T-cell functionality.

  18. Separation of parent homopolymers from poly(ethylene oxide) and polystyrene-based block copolymers by liquid chromatography under limiting conditions of desorption--1. Determination of the suitable molar mass range and optimization of chromatographic conditions.

    Science.gov (United States)

    Rollet, Marion; Pelletier, Bérengère; Altounian, Anaïs; Berek, Dusan; Maria, Sébastien; Phan, Trang N T; Gigmes, Didier

    2015-05-01

    We studied molar mass limits for the LC LCD separation of parent polystyrene (PS) and poly(ethylene oxide) (PEO) homopolymers from PEO/PS based block copolymers and we identified optimized chromatographic conditions. Time delays between barriers and sample injections were 0-2-3'10. Eluent was composed of dimethylformamide (DMF) 40 wt.% and 1-chlorobutane (CLB) 60 wt.%; Barrier 1 (B1), which retained block copolymer, was composed of 100 wt.% CLB and Barrier 2 (B2), which retained PEO, was a mixture of DMF and CLB, which proportions were adjusted to studied block copolymers. With B2 composed of DMF 23 wt.% and CLB 77 wt.%, we obtained successful separation of PS23K-b-PEO35K-b-PS23K (56.5 wt.% of PS, the subscripts indicate the molar mass in kg mol(-1) of each polymer part in the block copolymer) from its parent homopolymers. With B2 adjusted to DMF 30 wt.% and CLB 70 wt.%, PS2.3K-b-PEO3.1K (42.6 wt.% of PS) was also efficiently separated from its parent homopolymers.

  19. 测试条件对测定管材类聚乙烯树脂等温氧化诱导时间的影响%Effects of Test Conditions on Determination of Isothermal Oxidation Induction Time in Polyethylene Pipes

    Institute of Scientific and Technical Information of China (English)

    杨化浩; 者东梅; 桂华; 刘畅

    2013-01-01

    等温氧化诱导时间是检测聚乙烯燃气管材的一项重要指标.文章以4种管材类聚乙烯树脂为样品,分别分析了测量温度和试样制备方式对管材类聚乙烯树脂等温氧化诱导时间测试结果的影响.根据评价效果和实际测试需要给出了适合管材类聚乙烯树脂等温氧化诱导时间测定的试验条件.对规范塑料产品等温氧化诱导时间的测量工作具有借鉴意义.%Isothermal oxidation induction time was an important index of polyethylene (PE) pipes.Isothermal oxidation induction times of four PE pipe samples were determined on different conditions.Samples used for test were prepared in different ways and tests were performed at different temperatures.According to the results of tests,effects of test conditions on determination of isothermal oxidation induction time in polyethylene samples were investigated.Test condition fit for polyethylene pipes was given based on the results,and it had reference meanings for the determination of plastics.

  20. Polymerization of Ethylene Oxide, Propylene Oxide, and Other Alkylene Oxides: Synthesis, Novel Polymer Architectures, and Bioconjugation.

    Science.gov (United States)

    Herzberger, Jana; Niederer, Kerstin; Pohlit, Hannah; Seiwert, Jan; Worm, Matthias; Wurm, Frederik R; Frey, Holger

    2016-02-24

    The review summarizes current trends and developments in the polymerization of alkylene oxides in the last two decades since 1995, with a particular focus on the most important epoxide monomers ethylene oxide (EO), propylene oxide (PO), and butylene oxide (BO). Classical synthetic pathways, i.e., anionic polymerization, coordination polymerization, and cationic polymerization of epoxides (oxiranes), are briefly reviewed. The main focus of the review lies on more recent and in some cases metal-free methods for epoxide polymerization, i.e., the activated monomer strategy, the use of organocatalysts, such as N-heterocyclic carbenes (NHCs) and N-heterocyclic olefins (NHOs) as well as phosphazene bases. In addition, the commercially relevant double-metal cyanide (DMC) catalyst systems are discussed. Besides the synthetic progress, new types of multifunctional linear PEG (mf-PEG) and PPO structures accessible by copolymerization of EO or PO with functional epoxide comonomers are presented as well as complex branched, hyperbranched, and dendrimer like polyethers. Amphiphilic block copolymers based on PEO and PPO (Poloxamers and Pluronics) and advances in the area of PEGylation as the most important bioconjugation strategy are also summarized. With the ever growing toolbox for epoxide polymerization, a "polyether universe" may be envisaged that in its structural diversity parallels the immense variety of structural options available for polymers based on vinyl monomers with a purely carbon-based backbone.

  1. 不同类型聚乙烯光氧老化特性比较研究%Comparative Research on Degradation Properties of Different Types Polyethylene after Xenon Photo-oxidation Aging

    Institute of Scientific and Technical Information of China (English)

    代军; 晏华; 郭骏骏; 杨健健; 张寒松

    2016-01-01

    利用热重分析法、热分解动力学Coats-Redfern方法和力学性能测试研究了不同类型聚乙烯[高密度聚乙烯(PE-HD)、线型低密度聚乙烯(PE-LLD)、低密度聚乙烯(PE-LD)]在氙灯光氧老化条件下的热稳定性、动力学参数和力学性能的变化规律。结果表明,随着老化时间的延长,PE-LD的热稳定性下降幅度最大,且主要集中于老化后期;老化初期PE-HD,PE-LLD和PE-LD的活化能均下降较快,表明此时三者均发生了较为严重的老化现象,分子链断裂较为强烈,而老化后期活化能下降幅度顺序为PE-LD>PE-LLD>PE-HD,表明这个期间PE-LD的老化最为强烈;PE-LD比PE-HD和PE-LLD的弯曲强度和冲击强度下降更为显著,且主要集中于老化后期,PE-LLD的力学性能下降幅度次于PE-HD。3种聚乙烯光氧老化容易顺序依次为PE-LD>PE-LLD>PE-HD。%The evolution rules for thermal stability,kinetics parameters and mechanical properties of high,linear low and low density polyethylene (PE-HD,PE-LLD and PE-LD) after xenon photo-oxidation aging were studied by thermogravimetry analysis, thermal degradation kinetics Coats-Redfern method and mechanics experiment. The results show that with ongoing of aging time,the thermal stability of PE-LD decrease most quickly and mainly concentrated in the latter part of aging. At the beginning of the aging, the activation energy of PE-HD,PE-LLD and PE-LD decrease obviously,it indicates that the aging phenomenon of the three kinds of polyethylene is severe and chain breaking is more obviously. The activation energy decreases in order PE-LD>PE-LLD>PE-HD in the latter part of aging,which indicates that the aging of PE-LD is the strongest during the period. The bending strength and impact strength of PE-LD decrease significantly concentrated in the latter part of aging by comparison PE-HD and PE-LLD,the decrease extent for mechanical properties of PE-LLD is inferior to PE-HD. The easy aging

  2. Polyethylene Glycol Propionaldehydes

    Science.gov (United States)

    Harris, Joe M.; Sedaghat-Herati, Mohammad R.; Karr, Laurel J.

    1992-01-01

    New class of compounds derived from polyethylene glycol (PEG's) namely, PEG-propionaldehydes, offers two important advantages over other classes of PEG aldehyde derivatives: compounds exhibit selective chemical reactivity toward amino groups and are stable in aqueous environment. PEG's and derivatives used to couple variety of other molecules, such as, to tether protein molecules to surfaces. Biotechnical and biomedical applications include partitioning of two phases in aqueous media; immobilization of such proteins as enzymes, antibodies, and antigens; modification of drugs; and preparation of protein-rejecting surfaces. In addition, surfaces coated with PEG's and derivatives used to control wetting and electroosmosis. Another potential application, coupling to aminated surfaces.

  3. 一种有效的制备聚乙二醇修饰氧化石墨烯的方法%AN EFFECTIVE WAY TO PREPARE POLYETHYLENE GLYCOL-MODIFIED GRAPHENE OXIDE

    Institute of Scientific and Technical Information of China (English)

    余翠平; 石恒冲; 施德安; 殷敬华

    2012-01-01

    为提高氧化石墨烯(GO)的生物相容性从而扩展其在高性能生物材料制备中的应用,采用甲苯-2,4-二异氰酸酯作为桥联剂,制备了四臂星型聚乙二醇修饰氧化石墨烯(GO-TDI-sPEG),该产物在水中仍然可以稳定分散.采用傅里叶红外光谱( FTIR)、拉曼光谱(Raman)、X-射线衍射(XRD)、原子力显微镜(AFM)、透射电子显微镜(TEM)和热重分析(TGA)对接枝产物进行表征.产物在2861 cm-1和1093 cm-1处出现的特征红外吸收表明sPEG已接枝到GO上.产物的Raman光谱中D模与G模信号变弱,且ID/IG值变化不大,说明sPEG改性后的氧化石墨物理结构没有发生变化.XRD曲线上产物衍射峰消失,表明经聚合物修饰后氧化石墨被完全剥离.TGA数据表明原始GO在约160℃开始发生热失重,经修饰后,大约在260℃开始热失重,热稳定性增加了约100℃.由TEM图片可以观察到GO及改性石墨烯产物剥离程度较高,且片上分布有较多聚合物点.且AFM图片显示GO的平均厚度大约为0.85 nm,接上聚合物后部分厚度增加到约1.2 nm.%In order to improve the biocompatibility of graphene oxide ( GO) and enhance its application in preparing biomaterials, four-arm star polyethylene glyeol (sPEG) was used to modify GO under the assistance of toluene-2,4-diisocyanate (TDI). Polyethylene glycol-modified graphene oxide (GO-TDI-sPEG) obtained by this facile method possesses high sPEG grafting density,which could be stably suspended in aqueous solutions. Fourier transform infrared spectroscopy ( FTIR), Raman spectroscopy ( Raman ), X-ray diffraction (XRD), atomic force microscopy ( AFM ) , transmission electron microscopy ( TEM ) and thermogravimetric analysis (TGA) were used to characterize the resultant material. The appearance of the characteristic absorptions at 2861 and 1093 cm"1 in FTIR spectrum,as well as the AFM and TEM micrographs indicated that sPEG was successfully grafted onto GO. No diffraction peak could be

  4. Radiation processing of polyethylene

    Science.gov (United States)

    Barlow, A.; Biggs, J. W.; Meeks, L. A.

    This paper covers two areas (a) the use of high energy radiation for the synthesis and improvement of polymer properties and (b) the formulation of radiation curable compounds for automotive/appliance wire applications and high voltage insulation. The first part discusses the use of gamma radiation for the bulk polymerization of ethylene and the properties of the polymer produced. The use of low dose radiation to increase polymer molecular weight and modify polydispersity is also described together with its projected operational cost. An update is provided of the cost savings that can be realized when using radiation crosslinked heavy duty film, which expands its applications, compared with noncrosslinked materials. The second section of the paper considers the advantages and disadvantages of radiation vs. peroxide curing of wire and cable compounds. The formulation of a radiation curable, automotive/appliance wire compound is discussed together with the interactions between the various ingredients; i.e., base resin, antioxidants, flame retardant filler, coupling agents, processing aids and radiation to achieve the desired product. In addition, the general property requirements of a radiation curable polyethylene for high voltage insulation are discussed; these include crosslinking efficiency, thermal stability, wet tree resistance and satisfactory dielectric properties. Preliminary data generated in the development of a 230KV radiation crosslinked polyethylene insulation are included.

  5. Demulsification of W/O emulsion at petroleum field and reservoir conditions using some demulsifiers based on polyethylene and propylene oxides

    Directory of Open Access Journals (Sweden)

    A.M. Alsabagh

    2016-12-01

    Full Text Available In this work, polymer molecules of alkene oxides diesters with varying HLB values and molecular weights (ED1, ED2, ED3, PD1, PD2 and PD3 were synthesized, elsewhere (Alsabagh et al., 2016. The demulsification efficiency was evaluated at field and reservoir conditions. At field conditions (60 °C and 1 atm the data revealed that the maximum demulsification efficiency was obtained by ED3 and PD3 at 60 °C, 600 ppm after 55 and 40 min, respectively. At reservoir conditions (85 °C and 5000 psi, the PD3 and ED3 showed also the maximum demulsification efficiency was 76% and 70%, respectively, in spite of the 2% from the blank emulsion (12% BS&W separated after 7 days. The interfacial tension (IFT at the crude oil/water interface was measured for PD3 and ED3. From the results, it was found that the values of IFT were 0.7 and 0.8 mN m−1 respectively. The rheological behavior of the same demulsifiers was investigated. The results showed that the demulsifiers PD3 and ED3 enhance the dynamic viscosities (3.9 and 3.8 mPa s, respectively and the (τB yield values were 0.77 and 1.23 Pa s, respectively at temperature 85 °C, whereas, they were 3.95 mPa s and 1.5 Pa s for the blank emulsion sample.

  6. Polyurethane modified with an antithrombin-heparin complex via polyethylene oxide linker/spacers: influence of PEO molecular weight and PEO-ATH bond on catalytic and direct anticoagulant functions.

    Science.gov (United States)

    Sask, Kyla N; Berry, Leslie R; Chan, Anthony K C; Brash, John L

    2012-10-01

    A segmented polyurethane (PU) was modified with polyethylene oxides (PEO) of varying molecular weight and end group. The PEO served as linker/spacers to immobilize an antithrombin-heparin (ATH) anticoagulant complex on the PU. Isocyanate groups were introduced into the PU to enable attachment of either "conventional" homo-bifunctional dihydroxy-PEO (PEO-OH surface) or a hetero-bifunctional amino-carboxy-PEO (PEO-COOH surface). The PEO surfaces were functionalized with N-hydroxysuccinimide (NHS) groups using appropriate chemistries, and ATH was attached to the distal NHS end of the PEO (PEO-OH-ATH and PEO-COOH-ATH surfaces). Water contact angle and fibrinogen adsorption measurements showed increased hydrophilicity and reduced fibrinogen adsorption from buffer on all PEO surfaces compared to unmodified PU. ATH uptake on NHS-functionalized PEO was quantified by radiolabeling. Despite the different PEO molecular weights and end groups, and NHS-functionalization chemistries, the surface densities of ATH were similar. The adsorption of fibrinogen and antithrombin (AT) from plasma was measured in a single experiment using dual radiolabeling. On PEO-ATH surfaces fibrinogen adsorption was minimal while AT adsorption was high showing the selectivity of the heparin moiety of ATH for AT. The PEO-COOH-ATH surfaces showed slightly greater AT adsorption than the PEO-OH-ATH surfaces. Thrombin adsorption on all of the PEO-ATH surfaces was greater than on the corresponding PEO surfaces without ATH, and was highest on the PEO-OH-ATH, suggesting potential anticoagulant properties for this surface via direct thrombin inhibition by the AT portion of ATH.

  7. Effect of hydroxypropyl cellulose (HPC), polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) on Nd-TiO2/graphene oxide nanocomposite for removal of lead(II) and copper(II) from aquatic media.

    Science.gov (United States)

    Samadi, Susan; Mirseyfifard, Sayed Mohammad Hosain; Assari, Mina; Hassannejad, Marzieh

    2017-07-01

    In order to investigate the effect of hydroxypropyl cellulose (HPC), polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG) on adsorbing capacity of nanosorbent Nd-TiO2/GO, Nd-TiO2/HPC/GO, Nd-TiO2/PVP/GO and Nd-TiO2/PEG/GO nanocomposites were synthesized. Studies by Fourier transform infrared spectroscopy confirmed the expected structure and X-ray diffraction results confirmed the formation of crystalline phase of anatase titania and also graphene oxide (GO). Scanning electron microscopy pictures and energy dispersive X-ray spectroscopy analysis showed the formation of Nd-TiO2 nanoparticles. These nanocomposites were used for removal of lead(II) and copper(II) from water and the effective factors on removal were optimized. The results showed that the maximum removal for all three nanocomposites was at pH = 7. The amount of adsorbent and contact time for Nd-TiO2/HPC/GO and Nd-TiO2/PVP/GO nanocomposites was equal to 0.02 g and 20 minutes respectively, but they were equal to 0.01 g and 15 minutes for Nd-TiO2/PEG/GO nanocomposite. Investigating the effect of interfering ions showed they had no considerable effect on removal efficiency. In order to investigate the effect of photocatalytic activity in optimal conditions and in the presence of visible-ultraviolet light, the removal process was performed. The results showed an increase in removal efficiency. Furthermore, the ability of synthesized nanosorbents to decompose organic compounds available in water was confirmed and their energy band gaps were calculated.

  8. IMPORTANT DEGRADATIONS IN POLYETHYLENE TERAPHTALATE EXTRUSION PROCESS

    Directory of Open Access Journals (Sweden)

    Şule ALTUN

    2003-01-01

    Full Text Available Polyethylene terephthalate (PET is one of the most used thermo-plastic polymers. The total consumption of PET has been about 30 million tons in the year 2000. Polyester fibers constitute about 60 % of total synthetic fibers consumption. During extrusion, PET polymer is faced to thermal, thermo-oxidative and hydrolytic degradation, which result in severe reduction in its molecular weight, thereby adversely affecting its subsequent melt processability. Therefore, it is essential to understand degradation processes of PET during melt extrusion.

  9. Polyethylene glycol-functionalized poly (Lactic Acid-co-Glycolic Acid) and graphene oxide nanoparticles induce pro-inflammatory and apoptotic responses in Candida albicans-infected vaginal epithelial cells

    Science.gov (United States)

    Johnson, Shemedia J.; Danielsen, Zhixia Yan; Lim, Jin-Hee; Mudalige, Thilak; Linder, Sean

    2017-01-01

    Mucous-penetrating nanoparticles consisting of poly lactic acid-co-glycolic acid (PLGA)-polyethylene glycol (PEG) could improve targeting of microbicidal drugs for sexually transmitted diseases by intravaginal inoculation. Nanoparticles can induce inflammatory responses, which may exacerbate the inflammation that occurs in the vaginal tracts of women with yeast infections. This study evaluated the effects of these drug-delivery nanoparticles on VK2(E6/E7) vaginal epithelial cell proinflammatory responses to Candida albicans yeast infections. Vaginal epithelial cell monolayers were infected with C. albicans and exposed to 100 μg/ml 49.5 nm PLGA-PEG nanospheres or 20 μg/ml 1.1 x 500 nm PEG-functionalized graphene oxide (GO-PEG) sheets. The cells were assessed for changes in mRNA and protein expression of inflammation-related genes by RT-qPCR and physiological markers of cell stress using high content analysis and flow cytometry. C. albicans exposure suppressed apoptotic gene expression, but induced oxidative stress in the cells. The nanomaterials induced cytotoxicity and programmed cell death responses alone and with C. albicans. PLGA-PEG nanoparticles induced mRNA expression of apoptosis-related genes and induced poly (ADP-ribose) polymerase (PARP) cleavage, increased BAX/BCL2 ratios, and chromatin condensation indicative of apoptosis. They also induced autophagy, endoplasmic reticulum stress, and DNA damage. They caused the cells to excrete inflammatory recruitment molecules chemokine (C-X-C motif) ligand 1 (CXCL1), interleukin-1α (IL1A), interleukin-1β (IL1B), calprotectin (S100A8), and tumor necrosis factor α (TNF). GO-PEG nanoparticles induced expression of necrosis-related genes and cytotoxicity. They reduced autophagy and endoplasmic reticulum stress, and apoptotic gene expression responses. The results show that stealth nanoparticle drug-delivery vehicles may cause intracellular damage to vaginal epithelial cells by several mechanisms and that their use

  10. Polymeric micelles based on poly(ethylene oxide) and α-carbon substituted poly(ɛ-caprolactone): An in vitro study on the effect of core forming block on polymeric micellar stability, biocompatibility, and immunogenicity.

    Science.gov (United States)

    Garg, Shyam M; Vakili, Mohammad Reza; Lavasanifar, Afsaneh

    2015-08-01

    A series of block copolymers based on methoxy poly(ethylene oxide)-block-poly(ɛ-caprolactone) (PEO-b-PCL), PEO-b-PCL bearing side groups of benzyl carboxylate (PEO-b-PBCL), or free carboxyl (PEO-b-PCCL) on the PCL backbone with increasing degrees of polymerization of the PCL backbone were synthesized. Prepared block copolymers assembled to polymeric micelles by co-solvent evaporation. The physical stability of prepared micelles was assessed by measuring their tendency toward aggregation over time using dynamic light scattering (DLS). The resistance of micelles against dissociation in the presence of a micelle destabilizing agent, i.e., sodium dodecyl sulfate (SDS), was also investigated using DLS. The rate of micellar core degradation was determined using (1)H NMR for polymer molecular weight measurement upon incubation of micelles in PBS (pH=7.4) at 37°C followed by dialysis of the remaining polymer at different time intervals. The effect of pendent group chemistry in the micellar core on the adsorption of serum proteins to micellar structure was then evaluated using Bradford Protein assay kit. Finally, the effect of micellar core structure on the induction of bone marrow derived dendritic cell (BMDC) maturation and secretion of IL-12 was studied as a measure of micellar immunogenicity. The results showed micelle structures from polymers with higher degree of polymerization in the hydrophobic block and/or those with more hydrophobic substituents on the core-forming block, to be more stable. This was reflected by a decreased tendency for micellar aggregation, reduced dissociation of micelles in the presence of SDS, and diminished core degradation. All micelles were shown to have insignificant adsorption of serum protein suggesting that the hydrophilic PEO shell provided sufficient protection of the core. However, the protein adsorption increased with increase in the hydrophobicity and molecular weight of the core-forming block. Irrespective of the micellar core

  11. Molecular-Level Control of Ciclopirox Olamine Release from Poly(ethylene oxide)-Based Mucoadhesive Buccal Films: Exploration of Structure-Property Relationships with Solid-State NMR.

    Science.gov (United States)

    Urbanova, Martina; Gajdosova, Marketa; Steinhart, Miloš; Vetchy, David; Brus, Jiri

    2016-05-02

    Mucoadhesive buccal films (MBFs) provide an innovative way to facilitate the efficient site-specific delivery of active compounds while simultaneously separating the lesions from the environment of the oral cavity. The structural diversity of these complex multicomponent and mostly multiphase systems as well as an experimental strategy for their structural characterization at molecular scale with atomic resolution were demonstrated using MBFs of ciclopirox olamine (CPX) in a poly(ethylene oxide) (PEO) matrix as a case study. A detailed description of each component of the CPX/PEO films was followed by an analysis of the relationships between each component and the physicochemical properties of the MBFs. Two distinct MBFs were identified by solid-state NMR spectroscopy: (i) at low API (active pharmaceutical ingredient) loading, a nanoheterogeneous solid solution of CPX molecularly dispersed in an amorphous PEO matrix was created; and (ii) at high API loading, a pseudoco-crystalline system containing CPX-2-aminoethanol nanocrystals incorporated into the interlamellar space of a crystalline PEO matrix was revealed. These structural differences were found to be closely related to the mechanical and physicochemical properties of the prepared MBFs. At low API loading, the polymer chains of PEO provided sufficient quantities of binding sites to stabilize the CPX that was molecularly dispersed in the highly amorphous semiflexible polymer matrix. Consequently, the resulting MBFs were soft, with low tensile strength, plasticity, and swelling index, supporting rapid drug release. At high CPX content, however, the active compounds and the polymer chains simultaneously cocrystallized, leaving the CPX to form nanocrystals grown directly inside the spherulites of PEO. Interfacial polymer-drug interactions were thus responsible not only for the considerably enhanced plasticity of the system but also for the exclusive crystallization of CPX in the thermodynamically most stable

  12. Radiation resistivity of polyacenaphthylene-grafted polyethylene. [Gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hayakawa, K.; Kawase, K.; Yamakita, H. (Government Industrial Research Inst., Nagoya (Japan))

    1983-01-01

    Thin poly(ethylene-g-acenaphthylene) films prepared by the vapor-phase grafting method were subjected to the ..gamma..-irradiation in air, and various changes in tensile and structural properties of the film were investigated by comparing with those of the untreated or crosslinked polyethylene film. Polyethylene got to lose its inherent necking property by oxidative degradation and to be brittle-fractured by the irradiation dose less than 100 Mrad in air. The polyacenaphthylene-grafted polyethylenes, however, kept their ductility up to 200 Mrad or more, and the rate of increase in elastic modulus as well as yield strength with the increasing irradiation dose was considerably lower than that of untreated or crosslinked polyethylene. The effect of the grafting extent, and that of the irradiation dose-rate on the fracture energy were also examined. The weight increase of polyethylene due to the oxygen consumption and the resulting formation of carbonyl group which proceeded proportionally with the irradiation dose were remarkably suppressed by the grafting, whereas the double bond formation seemed to be unaffected by it. The grafted film held the original content of gel fraction unchanged during the irradiation in air, but the average molecular weight of the sol fraction decreased gradually.

  13. Polyethylene-Based Tadpole Copolymers

    KAUST Repository

    Alkayal, Nazeeha

    2017-02-15

    Novel well-defined polyethylene-based tadpole copolymers ((c-PE)-b-PS, PE: polyethylene, PS: polystyrene) with ring PE head and linear PS tail are synthesized by combining polyhomologation, atom transfer radical polymerization (ATRP), and Glaser coupling reaction. The -OH groups of the 3-miktoarm star copolymers (PE-OH)-b-PS, synthesized by polyhomologation and ATRP, are transformed to alkyne groups by esterification with propiolic acid, followed by Glaser cyclization and removal of the unreacted linear with Merrifield\\'s resin-azide. The characterization results of intermediates and final products by high-temperature size exclusion chromatography, H NMR spectroscopy, and differential scanning calorimetry confirm the tadpole topology.

  14. Polyethylene Glycol Camouflaged Earthworm Hemoglobin

    Science.gov (United States)

    Moges, Selamawit; Nacharaju, Parimala; Roche, Camille; Dantsker, David; Palmer, Andre; Friedman, Joel M.

    2017-01-01

    Nearly 21 million components of blood and whole blood and transfused annually in the United States, while on average only 13.6 million units of blood are donated. As the demand for Red Blood Cells (RBCs) continues to increase due to the aging population, this deficit will be more significant. Despite decades of research to develop hemoglobin (Hb) based oxygen (O2) carriers (HBOCs) as RBC substitutes, there are no products approved for clinical use. Lumbricus terrestris erythrocruorin (LtEc) is the large acellular O2 carrying protein complex found in the earthworm Lumbricus terrestris. LtEc is an extremely stable protein complex, resistant to autoxidation, and capable of transporting O2 to tissue when transfused into mammals. These characteristics render LtEc a promising candidate for the development of the next generation HBOCs. LtEc has a short half-life in circulation, limiting its application as a bridge over days, until blood became available. Conjugation with polyethylene glycol (PEG-LtEc) can extend LtEc circulation time. This study explores PEG-LtEc pharmacokinetics and pharmacodynamics. To study PEG-LtEc pharmacokinetics, hamsters instrumented with the dorsal window chamber were subjected to a 40% exchange transfusion with 10 g/dL PEG-LtEc or LtEc and followed for 48 hours. To study the vascular response of PEG-LtEc, hamsters instrumented with the dorsal window chamber received multiple infusions of 10 g/dL PEG-LtEc or LtEc solution to increase plasma LtEc concentration to 0.5, then 1.0, and 1.5 g/dL, while monitoring the animals’ systemic and microcirculatory parameters. Results confirm that PEGylation of LtEc increases its circulation time, extending the half-life to 70 hours, 4 times longer than that of unPEGylated LtEc. However, PEGylation increased the rate of LtEc oxidation in vivo. Vascular analysis verified that PEG-LtEc showed the absence of microvascular vasoconstriction or systemic hypertension. The molecular size of PEG-LtEc did not change the

  15. 76 FR 70896 - Polyethylene Glycol; Tolerance Exemption

    Science.gov (United States)

    2011-11-16

    ... AGENCY 40 CFR Part 180 Polyethylene Glycol; Tolerance Exemption AGENCY: Environmental Protection Agency... amu), 17,000; also known as polyethylene glycol, when used as an inert ingredient in a pesticide...(oxyethylene, minimum number average molecular weight (in amu), 17,000; also known as polyethylene...

  16. Mechanical properties of polyethylene foils

    Directory of Open Access Journals (Sweden)

    Ľubomír KUBÍK

    2014-03-01

    Full Text Available The paper deals with the evaluation of the mechanical properties of the polyethylene foils such as the stress, strain, modulus of elasticity and stress and strain in the moment of breaking. The thin foils (50 mm which contained 91 % of polyethylene Bralen RA 2–63 and 9 % colored concentrate Maxithen were studied. Four sorts of foils were examined: Maxithen HP 1510 – white, Maxithen HP 231111 – yellow, Maxithen HP 533031 – blue and Maxithen HP 533 041 – violet. Longitudinal and transversal tensile properties were studied. The tensile behavior was monitored on the motorized test stand ANDILOG STENTOR 1000. The moduli of elasticity of longitudinal samples of polyethylene Bralen RA 2—63 foils achieved the values in the range from 222.73 MPa to 298.24 MPa and the transversal samples in the range 179.61 MPa to 270.41 MPa. The stress of longitudinal samples of polyethylene Bralen RA 2–63 foils in the moment of the rupture achieved the values in the range from 9.46 MPa to 13.33 MPa at the strain from 1.51 mm*mm–1 to 1.54 mm*mm–1 and the transversal samples in the range from 12.38 MPa to 15.54 MPa at the strain from 1.48 mm*mm–1 to 1.58 mm*mm–1.

  17. Preparation of amino-terminated poly(ethylene glycol)by periodate oxidation%高碘酸氧化法制备端氨基聚乙二醇的研究

    Institute of Scientific and Technical Information of China (English)

    陈阳建; 许丽丽; 张新波; 彭富君; 宋潇达

    2015-01-01

    Monomethoxy poly( ethylene glycol)tosylate( mPEG5000-OTs)was synthesized by sulfonic esterification from monomethoxy poly(ethylene glycol)5000(mPEG5000)and p-toluenesulfonyl chloride (p-TsCl),and then reacted with ethanolamine as nucleophile to produce a new poly(ethylene glycol)in-termediate with the β-amino alcohol structure at the end. Amino-terminated poly( ethylene glycol ) (mPEG5000-NH2 )with the relative molecular mass of 5 000 was 75. 1% . The structures of products were characterized and identified by IR and 1 H NMR.%单甲氧基聚乙二醇5000(mPEG5000)和对甲苯磺酰氯(p-TsCl)磺酸酯化,得到单甲氧基聚乙二醇对甲苯磺酸酯(mPEG5000-OTs),与乙醇胺亲核取代反应,获得末端具有β-氨基醇结构的聚乙二醇中间体,用高碘酸盐氧化,得相对分子质量5000的端氨基聚乙二醇(mPEG5000-NH2),总收率75.1%,产物结构通过 IR 和1 H NMR 进行表征。

  18. A fixed cations and low Tg polymer: the poly(4-vinyl-pyridine) quaternized by poly(ethylene oxide) links. Conductivity study; Un electrolyte polymere a cations fixes et bas Tg: les poly(4-vinylpyridine) quaternisees par des chainons de poly(oxyde d`ethylene). Etude de la conductivite

    Energy Technology Data Exchange (ETDEWEB)

    Gramain, Ph. [Ecole Nationale Superieure de Chimie de Montpellier, 34 (France); Frere, Y. [Centre National de la Recherche Scientifique (CNRS), 67 - Strasbourg (France). Institut Charles Sadron

    1996-12-31

    The spontaneous ionic polymerization of 4-vinyl-pyridine in presence of mono-tosylated or bromated short chains of poly(ethylene oxide)-(PEO) is used to prepare amorphous comb-like poly-cations with low Tg. The polymer electrolyte properties of these new structures have been studied without any addition of salts. The ionic conductivity of these fixed cation poly-electrolytes depends on the length of the grafted PEO and varies from 10{sup -7} to 10{sup -4} S/cm between 25 and 80 deg. C. It is only weakly dependent on the nature of the cation but it is controlled by the movements of the pyridinium cation which are facilitated by the plastifying effect of the POE chains which do not directly participate to the ionic transport. (J.S.) 17 refs.

  19. Effect of polyethylene oxide on renal hemodynamics in rabbits with endotoxin shock%聚环氧乙烷对内毒素休克兔肾血流动力学的影响

    Institute of Scientific and Technical Information of China (English)

    方琴; 胡振华; 陈仲清; 段星星; 陈辉; 傅卫军; 魏红云

    2012-01-01

    Objective To investigate the effect of polyethylene oxide (PEO) on renal blood flow and its renoprotective effect in rabbits with endotoxin sepsis.Methods Twenty normal New Zealand white rabbits were randomly divided into normal saline (NS) group and PEO group (n=10),and endotoxin shock was induced by an intravenous injection of 0.6 mg/kg lipopolysaccharide.Resuscitation was performed when the blood pressure of the rabbits showed a 30% decline,using NS (in NS group) or the mixture of equal volumes of NS and 20 ng/g PEO (in PEO group) perfused at the rate of 5 ml/kg per hour.Before and during shock and at 1 h after resuscitation,the renal hemodynamics was monitored by ultrasound and the venous blood was extracted to examine the renal functions.The heart rate and arterial blood pressure were monitored throughout the experiment.Results The rabbits in both groups showed a significantly lower renal artery blood flow velocity during the shock (P<0.05) with significantly increased pulsatility index (PI) and resistance index (RI) compared with those before the shock.One hour after resuscitation,the blood flow velocity in the renal arteries at all levels and the tertiary veins were reduced in NS group without obvious reduction of the PI and RI; in PEO group,the blood flow velocities in the renal arteries increased significantly compared to those before shock (P<0.05),and the PI and RI of the tertiary arteries were significantly lower than those in NS group (P<0.05).In both groups,BUN and Cr increased during endotoxin shock stage,and 1 h after resuscitation,PEO group showed significantly lower BUN and Cr levels than NS group (P<0.05).Conclusion A small dose of PEO can significantly promote renal perfusion in rabbits with septic shock,thus offering renoprotective effect against early damage in septicopyemia and septic shock.%目的 应用超声监测内毒素休克新西兰免肾血流,观察聚环氧乙烷(PEO)对内毒素休克免肾血流的影响

  20. Drying poly(ethylene glycol)

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Lucas Kinard, Kurtis Kasper & Antonios Mikos ### Abstract This protocol describes the drying of poly(ethylene glycol) (PEG) by a simple 6 step procedure. One can implement this protocol using common lab glass and lab equipment. Water is removed from PEG by azeotropic distillation in toluene. The two components are mixed and toluene and water are distilled off by heating the solution to 170°C. This procedure can be implemented in ~2 h. ### Introduction In many ...

  1. Laser patterned carbon–polyethylene mesh electrodes for wound diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Phair, Jolene; Joshi, Mayank; Benson, John; McDonald, Damian; Davis, James, E-mail: james.davis@ulster.ac.uk

    2014-02-14

    Carbon loaded polyethylene films were selected as the base substrate for a mechanically flexible and conductive sensing material for use wound monitoring technologies. The films were processed using laser ablation of the surface to increase the effective surface area of the electrode and then subject to an oxidative electrochemical etch to improve the electron transfer kinetics. The surface morphology of the resulting films was analysed and the electrode performance in relation to monitoring uric acid, a key wound biomarker, was optimized. A prototype smart bandage was designed, based on interfacing the mesh to a portable potentiostat, and the response to urate and potential interferences assessed. - Highlights: • Innovative use of a carbon–polyethylene mesh for wound sensing applications. • Electroanalytical characterisation of a mechanically flexible conductive film. • Design and preliminary characterisation of an integrated smart bandage.

  2. Positronium diffusion in crystalline polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Serna, J. (Dept. de Fisica de Materiales, Univ. Complutense, Madrid (Spain))

    1990-12-16

    The analysis in four components of the positron lifetime spectra of nine different and structurally well characterised lamellar polyethylene samples has allowed to associate the two longest-lived components to positronium annihilation in the crystalline and amorphous phases. Further assumption on positronium tunneling through the interface between both phases, and a simple geometrical model, led to a value for the positronium diffusion coefficient in the crystalline phase of the order of 10{sup -4} cm{sup 2}/s. Interfaces have thicknesses around 1.5 nm and are shallow traps for positronium. (orig.).

  3. Effect of trifunctional monomers and antioxidants on crosslinking reaction of polyethylene. [Electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Pyun, H.C.; Lee, Y.C.; Kim, K.J.; Yoon, B.M. (Korea Advanced Energy Research Inst., Seoul (Republic of Korea))

    1982-06-01

    The crosslinking reaction and oxidative stability of low-density polyethylene were studied in the presence of trifunctional monomers and antioxidants with electron beams. The trifunctional monomers used in this study are Trimethylolpropane triacrylate (TMPTA), Trimethylolpropane trimethacrylate (TMPTM) and Triallyl cyanurate (TAC). And the antioxidants are Irganox 1010 (Pentaerythritoltetrakis(3-(3,5-di-t-butyl-4-hydroxyphenly)-propionate)), Santonox R(4,4'-Thio-bis(3-methyl-6-t-butylphenol)), Nocrac D(N-phenyl-..beta..-naphthylamine) and Bisphenol A(4,4'-Isopropylidene bisphenol). Among the monomers, TMPTA is the best crosslinking agent and provides polyethylene with oxidative stability. Among the antioxidants, Nocrac D is the best antioxidant for polyethylene.

  4. Diffusion of limonene in polyethylene.

    Science.gov (United States)

    Limm, W; Begley, T H; Lickly, T; Hentges, S G

    2006-07-01

    Diffusion coefficients of limonene in various linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE) resins have been determined from sorption data using a thermogravimetric methodology. From these data, one can determine whether polymer synthesis parameters such as the choice of catalytic process or co-monomer result in substantial differences in how much food packaging additives might migrate to food. For example, LLDPE is currently manufactured using either one of two distinct catalytic processes: Ziegler-Natta (ZN) and metallocene, a single-site catalyst. ZN catalysis is a heterogeneous process that has dominated polyolefin synthesis over the last half-century. It involves a transition metal compound containing a metal-carbon bond that can handle repeated insertion of olefin units. In contrast, metallocene catalysis has fewer than 20 years of history, but has generated much interest due to its ability to produce highly stereospecific polymers at a very high yield. In addition to high stereospecificity, metallocene-catalysed polymers are significantly lower in polydispersity than traditional ZN counterparts. Absorption and desorption testing of heat-pressed films made from LLDPE and LDPE resins of varying processing parameters indicates that diffusion coefficients of limonene in these resins do not change substantially.

  5. Preparation, Characterization and Dielectric Properties of Epoxy and Polyethylene Nanocomposites

    Science.gov (United States)

    Zhang, Chao; Mason, Ralf; Stevens, Gary

    Two very different kinds of polymer nanocomposites have been prepared, characterized and investigated by dielectric spectroscopy to investigate the effects of polymer-nanofiller matrix difference on the dielectric response of nanodielectric composites. Linear low density polyethylene (LLDPE) is a non-polar thermoplastic which has a high viscosity even in the melt phase and bisphenol-A epoxy resin with an anhydride hardener is a polar low viscosity thermosetting resin. Nanometric sized aluminium oxide filler was chosen as the common inorganic phase for both nanodielectrics. Generally, nanoparticles aggregate easily and are difficult to separate due to strong surface interactions. In this study various mixing methods were employed from ultrasonic liquid processing to controlled shear flow mixing to investigate the dispersion of the nanofillers. The resultant epoxy and polyethylene nanocomposites were characterized with SEM, TEM, and DSC. The dielectric properties and frequency response of the nanocomposites were measured in the frequency domain from 10-2 Hz to 106 Hz at different temperatures. In polyethylene nanocomposites, significant interfacial polarization is clearly seen. However, in epoxy nanocomposites, no obvious interfacial polarization is found. The results are discussed in terms of the difference in the electrical characteristics of the interfacial region between the polymers and the nano-alumina.

  6. Polyethylene crystallization in compatibilized polyethylene/polyamide 6 blends

    Science.gov (United States)

    Ceccia, Simona; Hynstova, Katerina; Fabre, Alexandra; Trouillet-Fonti, Lise; Long, Didier; Sotta, Paul

    2011-03-01

    Blends of semicrystalline polymers can exhibit much better properties than each of the pure polymers regarding e.g. impact/modulus compromise. Controlling the crystallization mechanisms (nucleation, kinetics) is a key factor to obtain the desired morphologies which lead to these unique properties. We have studied the crystallization of polyethylene (PE) in blends of PE and polyamide 6 (PA) compatibilized by PE functionalized with maleic anhydride (PE-g-MA, 1 wt% MA) obtained by reactive blending. Samples with different amounts of PA6 (0-60 %vol) have been investigated by polarized optical microscopy and Differential Scanning Calorimetry. The samples were heated at a temperature above the melting temperature of PE and below the melting temperature of PA, and then cooled at the selected crystallization temperature. We describe how the crystallization kinetics is modified by the presence of PA and MA.

  7. Properties of Polyethylene Naphthalate Track Membranes

    CERN Document Server

    Akimenko, S N; Orelovich, O L; Maekawa, J; Ioshida, M; Apel, P Yu

    2002-01-01

    Basic characteristics of track membranes made of polyethylene naphthalate (which is a polyester synthesized from dimethyl naphthalate and ethylene glycol) are studied and presented. Polyethylene naphthalate possesses some properties (mechanical strength, thermal and chemical stability), which make this polymer a promising material for the production of track membranes. Water flow rate and air flow rate characteristics, burst strength, wettability, and amount of extractables are determined. Surface structure and pore structure are examined using scanning electron microscopy. It is found that the pores in the membranes are cylindrical in shape. The measured water and air flow rates follow known theoretical relations for the transport in narrow capillaries. The burst strength of polyethylene naphthalate membranes is found to be similar to that of polyethylene terephthalate track membranes. Polyethylene naphthalate track membranes can be categorized as moderately hydrophilic. Being treated with boiling water, pol...

  8. Degradation of crosslinked polyethylene in water by gamma-irradiation

    Science.gov (United States)

    Matsui, Tatsuro; Takano, Tadao; Takayama, Shigeru; Ito, Masayuki; Narisawa, Ikuo

    2002-02-01

    The degradation of crosslinked polyethylene by gamma-irradiation in water was studied. Change in the physical properties and the growth of carbonyl group after irradiation showed a good correlation. The degradation observed at 80°C is the least, and that at 60°C is the severest. The distribution of the oxidized layer in the sample was measured and was also calculated from the diffusion model using the observed parameters. Comparison of both results suggest that some products caused by gamma-irradiation of water supress the degradation of XLPE at 80°C.

  9. Biotribology of a vitamin E-stabilized polyethylene for hip arthroplasty - Influence of artificial ageing and third-body particles on wear.

    Science.gov (United States)

    Grupp, Thomas M; Holderied, Melanie; Mulliez, Marie Anne; Streller, Rouven; Jäger, Marcus; Blömer, Wilhelm; Utzschneider, Sandra

    2014-07-01

    The objective of our study was to evaluate the influence of prolonged artificial ageing on oxidation resistance and the subsequent wear behaviour of vitamin E-stabilized, in comparison to standard and highly cross-linked remelted polyethylene (XLPE), and the degradation effect of third-body particles on highly cross-linked remelted polyethylene inlays in total hip arthroplasty. Hip wear simulation was performed with three different polyethylene inlay materials (standard: γ-irradiation 30 kGy, N2; highly cross-linked and remelted: γ-irradiation 75 kGy, EO; highly cross-linked and vitamin E (0.1%) blended: electron beam 80 kGy, EO) machined from GUR 1020 in articulation with ceramic and cobalt-chromium heads. All polyethylene inserts beneath the virgin references were subjected to prolonged artificial ageing (70°C, pure oxygen at 5 bar) with a duration of 2, 4, 5 or 6 weeks. In conclusion, after 2 weeks of artificial ageing, standard polyethylene shows substantially increased wear due to oxidative degradation, whereas highly cross-linked remelted polyethylene has a higher oxidation resistance. However, after enhanced artificial ageing for 5 weeks, remelted XLPE also starts oxidate, in correlation with increased wear. Vitamin E-stabilized polyethylene is effective in preventing oxidation after irradiation cross-linking even under prolonged artificial ageing for up to 6 weeks, resulting in a constant wear behaviour.

  10. Tribology, UV degradation, and structure-property-processing relationships of detonation nanodiamond-polyethylene nanocomposites

    Science.gov (United States)

    Tipton, John

    Nanoscale reinforcements offer the possibility of coupling the already proven high strength to weight properties of polymer matrix composites with additional multifunctional properties such as electrical conductivity, thermal conductivity, unique optics, UV/IR radiation absorption, and enhanced wear resistance. This work presents materials based on detonation nanodiamonds dispersed in two types of polyethylene. The work begins with an understanding of nucleation phenomena. It was discovered through isothermal kinetics using differential scanning calorimetry that nanodiamonds act as nucleating agents during polyethylene crystallization. A processing technique to disperse nanodiamonds into very viscous ultra-high molecular weight polyethylene was developed and analyzed. These composites were further studied using dynamic mechanical analysis which showed increases in both stiffness and energy absorbing modes over unfilled UHMWPE. Exposure to UV degradation caused a failure of the polymer microstructure which was found to be caused by residual tensile stresses between the polymer particles formed during processing. These high stress regions were more prone to photo oxidation even though the nanodiamond particles were shown to decrease surface oxidation. Additionally, the tribological properties of UHMWPE/nanodiamond composites were investigated. Ultra-high molecular weight polyethylene is an already proven ultra tough and wear resistant polymer that is used in many high performance thermoplastic applications such as bearings, surfaces (skids/wheels), ropes/nets, and orthopedic implants. This work showed that UHMWPE loaded with 5.0wt% nanodiamonds might be a candidate to replace the currently used crosslinked polyethylene material used in orthopedic implants.

  11. 超声监测聚环氧乙烷对内毒素休克兔肝脏血流的影响%Effect of Polyethylene Oxide on Hepatic Hemodynamics of Septic Shock in Rabbits by Ultrasonic Monitoring

    Institute of Scientific and Technical Information of China (English)

    胡振华; 方琴; 陈仲清; 陈辉; 傅卫军; 曾振华; 韦?

    2012-01-01

    [Objcctive]To explore the influence of polyethylene oxidc(PEO) on hepatic hemodynamics and its protective effect on liver after septic shock. [Methods] Twenty healthy New Zealand white rabbits were randomly divided into NS group( n =10) and PEO group( n =%[目的]探讨聚环氧乙烷(PEO)对感染休克后肝脏血流的影响及对肝脏的保护作用.[方法]健康新西兰白兔20只随机分为对照组(NS组)和PEO组,每组10只,禁饮食12 h,静脉注射内毒素0.6 mg/kg造成感染休克.PEO组使用含50 ppm聚环氧乙烷的生理盐水的进行复苏,NS组使用生理盐水复苏,均为5 mL/(h·kg).比较两组休克前期(T0)、休克期(T1)和复苏后(T2)肝脏门静脉(PV)、肝固有动脉(HA)血流速度及炎症因子.[结果]两组白兔T2时血压较T1时进一步降低(P0.05).[结论]小剂量聚环氧乙烷能够明显提高感染休克时肝脏的血流灌注,但对于早期肝脏损害及炎症反应并无明显改善作用.

  12. High performance polyethylene nanocomposite fibers

    Directory of Open Access Journals (Sweden)

    A. Dorigato

    2012-12-01

    Full Text Available A high density polyethylene (HDPE matrix was melt compounded with 2 vol% of dimethyldichlorosilane treated fumed silica nanoparticles. Nanocomposite fibers were prepared by melt spinning through a co-rotating twin screw extruder and drawing at 125°C in air. Thermo-mechanical and morphological properties of the resulting fibers were then investigated. The introduction of nanosilica improved the drawability of the fibers, allowing the achievement of higher draw ratios with respect to the neat matrix. The elastic modulus and creep stability of the fibers were remarkably improved upon nanofiller addition, with a retention of the pristine tensile properties at break. Transmission electronic microscope (TEM images evidenced that the original morphology of the silica aggregates was disrupted by the applied drawing.

  13. Molecular deformation mechanisms in polyethylene

    CERN Document Server

    Coutry, S

    2001-01-01

    adjacent labelled stems is significantly larger when the DPE guest is a copolymer molecule. Our comparative studies on various types of polyethylene lead to the conclusion that their deformation behaviour under drawing has the same basis, with additional effects imputed to the presence of tie-molecules and branches. Three major points were identified in this thesis. The changes produced by drawing imply (1) the crystallisation of some of the amorphous polymer and the subsequent orientation of the newly formed crystals, (2) the re-orientation of the crystalline ribbons and (3) the beginning of crystallite break-up. However, additional effects were observed for the high molecular weight linear sample and the copolymer sample and were attributed, respectively, to the presence of tie-molecules and of branches. It was concluded that both the tie-molecules and the branches are restricting the molecular movement during deformation, and that the branches may be acting as 'anchors'. This work is concerned with details...

  14. A comparison of the wear and physical properties of silane cross-linked polyethylene and ultra-high molecular weight polyethylene.

    Science.gov (United States)

    Sakoda, H; Voice, A M; McEwen, H M; Isaac, G H; Hardaker, C; Wroblewski, B M; Fisher, J

    2001-12-01

    Cross-linked polyethylenes are being introduced widely in acetabular cups in hip prostheses as a strategy to reduce the incidence of wear debris-induced osteolysis. It will be many years before substantial clinical data can be collected on the wear of these new materials. Silane cross-linked polyethylene (XLPE) was introduced into clinical practice in a limited series of acetabular cups in 1986 articulating against 22.225-mm alumina ceramic femoral heads and showed reduced wear rates compared with conventionally sterilized (gamma irradiation in air) ultra-high molecular weight polyethylene (UHMWPE). We compared the wear of XLPE manufactured in 1986 with the wear of UHMWPE manufactured in 1986 in nonirradiated and irradiated forms. In the nonirradiated forms, the wear of XLPE was 3 times less than UHWMPE when articulating against smooth counterfaces. The nonirradiated materials did not show signs of oxidation. In the irradiated forms, only UHMWPE showed high levels of oxidation, and this caused a substantial increase in wear. Antioxidants added to XLPE during processing gave resistance to oxidative degradation. When sliding against scratched counterfaces, the wear of UHMWPE increased by a factor of 2 to 3 times. Against the same scratched counterfaces, the wear of XLPE increased dramatically by 30 to 200 times. This difference may be attributed to the reduction in toughness of XLPE. Clinically, XLPE has been articulated against damage-resistant ceramic heads, and this probably has been an important factor in contributing to reduced wear. New cross-linked polyethylenes differ considerably from XLPE. This study indicates that it is prudent to examine the wear of new polyethylenes under a range of conditions that may occur in vivo.

  15. RECENT DEVELOPMENTS IN PHOTOINITIATED CROSSLINKING OF POLYETHYLENE AND ITS INDUSTRIAL APPLICATIONS

    Institute of Scientific and Technical Information of China (English)

    Baojun Qu

    2001-01-01

    The recent developments in the photoinitiated cross-linking of polyethylene and the significant breakthrough of its industrial application are reviewed. The enhanced photo-initiation system, the dynamics of photoinitiated crosslinking, the optimum conditions, the crystal morphological structures and related properties, and the photo- and thermo-oxidation stability of photocrosslinked polyethylene (XLPE) materials have been elucidated systematically. A new technique for producing photocrosslinked XLPE-insulated wire and cable is described in detail. It can be expected that the future applications ofphotocrosslinking technique of polyolefins will be very promising.

  16. Crystallization studies of polyethylene -poly(ethylene glycol) graft copolymers

    Science.gov (United States)

    Mark, P. R.; Hovey, G. E.; Murthy, N. S.; Breitenkamp, K.; Kade, M.; Emerick, T.

    2006-03-01

    Structure and crystallization behavior of three copolymers obtained by grafting poly (ethylene glycol) (PEG) chains to polyethylene (PE) main chain was investigated by variable temperature x-ray diffraction and thermal analysis. The results show that PEG side chains and PE main chains crystallize into separate domains. This is especially true when grafted chains are long (50 and 100 repeat units), in which the PEG domains are same as in PEG homopolymer both in structure and in melting behavior. In the copolymer with shorter chains (25 repeat units), the PEG crystals are not distinct and melting is broad. The PEG domains can be dissolved in water or ethanol without altering the mechanical integrity of the film. PE crystallites in both samples are similar to that in PE homopolymer. For instance, the thermal expansion of the basal cell plane (a- and b-axes) of the PE domains agrees well with that of PE homopolymer over the entire temperature range from ambient to melt. However, the chain-axis dimension PE-lattice in the copolymer is shorter by ˜ 0.05 å and the basal dimensions are larger by ˜ 0.05 å. The changes in these dimensions due to the changes in the length of the grafted PEG chains were investigated.

  17. Reuse of polyethylene waste in road construction.

    Science.gov (United States)

    Raju, S S S V Gopala; Murali, M; Rengaraju, V R

    2007-01-01

    The cost of construction of flexible pavements depends on thickness of the pavement layers. The thickness of pavement mainly depends on the strength of the subgrade. By suitable improvement to the strength of the subgrade, considerable saving in the scarce resources and economy can be achieved. Because of their lightweight, easy handling, non-breakable and corrosion free nature, polyethylene have surpassed all other materials in utility. But polyethylene waste has been a matter of concern to environmentalists as it is non-biodegradable. In this investigation, an attempt has been made to study the improvement of California Bearing Ratio (CBR) value of soils stabilized with waste polyethylene bags. This alternative material is mixed in different proportions to the gravel and clay to determine the improvement ofCBR value. Use of the waste polyethylene bags observed to have a significant impact on the strength and economy in pavement construction, when these are available locally in large quantities.

  18. Maxillofacial prostheses of chlorinated polyethylene.

    Science.gov (United States)

    May, P D

    1978-05-01

    There is clearly a need for maxillofacial prosthetic materials with improved properties. The chlorinated polyethylenes are thermoplastic elastomers which have particularly promising properties, and were used by us to prepare improved maxillofacial prostheses. Suitable CPE resins were compounded with other polymers and with pigments on a heated rubber mill to form thin sheets in a variety of shades. These were heated at 190 degrees C for 10 min and placed between heated linotype mold halves. The prosthesis was formed in a hand press. Sometimes heating and pressing were repeated. After cooling in water, the prosthesis was removed and hand-shaded with oil-soluble dyes. Physical properties were evaluated using standard techniques; skin irritation studies were conducted by 14-day insult patch tests on rabbits. Clinical evaluations were conducted on human volunteers. Parallel evaluations were conducted on commerically available materials for comparison. The CPE was superior to all of the three commerical materials in most properties, and comparable to the better of the three in the remaining properties. On balance, CPE was significantly superior. Early results indicate that the materials and techniques required are easily handled in the dental lab and that the final prosthesis has excellent aesthetic and patient acceptability.

  19. Morphology of polyethylene ski base materials.

    Science.gov (United States)

    Fischer, Jörg; Wallner, Gernot M; Pieber, Alois

    2010-03-01

    We used high-resolution Raman spectroscopy and differential scanning calorimetry for a comprehensive analysis of carbon black-filled polyethylene ski base grades at processing stages from the raw material to the structured ski base. Based on Raman mapping, we assessed the applicability of an advanced evaluation procedure for amorphous, disordered, and crystalline phase fractions of polyethylene for polyethylene extrusion and sinter grades. For sinter grades, a sufficient segregation between carbon black and polyethylene was confirmed, allowing for a comprehensive Raman spectroscopic morphological analysis. Significant morphological changes in polyethylene due to processing from the raw material to the semi-finished film and to the structured ski base were identified. Throughout the processing chain, we observed a decrease in crystallinity and an increase in the amorphous phase fraction. Although the raw material and the sintered semi-finished film exhibited a different but uniform polyethylene morphology, the morphological changes due to structuring of the ski base are limited to the top surface layer. The highest amorphous phase fractions were detected in the surface of the structured ski bases.

  20. Communication: Band bending at the interface in polyethylene-MgO nanocomposite dielectric

    Science.gov (United States)

    Kubyshkina, Elena; Unge, Mikael; Jonsson, B. L. G.

    2017-02-01

    Polymer nanocomposite dielectrics are promising materials for electrical insulation in high voltage applications. However, the physics behind their performance is not yet fully understood. We use density functional theory to investigate the electronic properties of the interfacial area in magnesium oxide-polyethylene nanocomposite. Our results demonstrate polyethylene conduction band matching with conduction bands of different surfaces of magnesium oxide. Such band bending results in long range potential wells of up to 2.6 eV deep. Furthermore, the fundamental influence of silicon treatment on magnesium oxide surface properties is assessed. We report a reduction of the surface-induced states at the silicon-treated interface. The simulations provide information used to propose a new model for charge trapping in nanocomposite dielectrics.

  1. Separation of parent homopolymers from polystyrene and poly(ethylene oxide) based block copolymers by liquid chromatography under limiting conditions of desorption-3. Study of barrier efficiency according to block copolymers' chemical composition.

    Science.gov (United States)

    Rollet, Marion; Pelletier, Bérengère; Berek, Dušan; Maria, Sébastien; Phan, Trang N T; Gigmes, Didier

    2016-09-02

    Liquid Chromatography under Limiting Conditions of Desorption (LC LCD) is a powerful separation tool for multicomponent polymer systems. This technique is based on a barrier effect of an appropriate solvent, which is injected in front of the sample, and which decelerates the elution of selected macromolecules. In this study, the barrier effects have been evaluated for triblock copolymers polystyrene-b-poly(ethylene oxide)-b-polystyrene (PS-b-PEO-b-PS) according to the content of polystyrene (wt% PS) and PEO-block molar mass. PS-b-PEO-b-PS samples were prepared by Atom Transfer Radical Polymerization (ATRP). The presence of respective parent homopolymers was investigated by applying optimized LC LCD conditions. It was found that the barrier composition largely affects the efficiency of separation and it ought to be adjusted for particular composition range of block copolymers.

  2. Influence of 2,6 (N-pyrazolyl)isonicotinic acid on the photovoltaic properties of a dye-sensitized solar cell fabricated using poly(vinylidene fluoride) blended with poly(ethylene oxide) polymer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Ganesan, S.; Muthuraaman, B.; Mathew, Vinod; Vadivel, M. Kumara [Department of Energy, University of Madras, Maraimalai Campus, Guindy, Chennai 600 025 (India); Maruthamuthu, P., E-mail: pmaruthu@yahoo.com [Department of Energy, University of Madras, Maraimalai Campus, Guindy, Chennai 600 025 (India); Ashokkumar, M. [School of Chemistry, University of Melbourne, VIC 3010 (Australia); Suthanthiraraj, S. Austin [Department of Energy, University of Madras, Maraimalai Campus, Guindy, Chennai 600 025 (India)

    2011-10-01

    Highlights: > 2,6 (N-pyrazolyl)isonicotinic acid (BNIN) has been synthesized through a simple and cost-effective method to produce good yield. > For the first time, attempt is made to use the synthesized BNIN in PVdF-PEO based polymer electrolyte as a plasticizer. > This enhanced the conductivity of polymer and increased the efficiency of DSSCs. > The fabricated solar cell exhibited efficiency as high as 7.3%. > This is comparatively higher than those of the present day DSSCs fabricated with Poly (vinylidine fluoride) polymer electrolyte. - Abstract: A novel method of introducing a synthesized organic nitrogenous compound 2,6 (N-pyrazolyl)isonicotinic acid (BNIN) and its effect on the conduction behavior of poly(vinylidene fluoride) (PVdF)-poly(ethylene oxide) (PEO) polymer-blend electrolyte with potassium iodide (KI) and iodine (I{sub 2}) and the corresponding performance of the dye-sensitized solar cells (DSSCs) were studied. A systematic investigation of the blends using FTIR provides evidence of interaction of BNIN with the polymer. Differential scanning calorimetry (DSC) study proves the miscibility of these polymers. Due to the coordinating and plasticizing effects of BNIN, the ionic conductivity of polymer blend electrolytes is enhanced. The efficiency of DSSC using BNIN doped polymer blend electrolyte was 7.3% under an illumination of 60 mW cm{sup -2} were observed for the best performance of a solar cell in this work.

  3. 超高分子量聚乙烯纤维的液相氧化改性及其环氧树脂基复合材料的力学和摩擦性能∗%Liquid-phase Oxidation Modification of Ultra-high Molecular Weight Polyethylene Fiber and Mechanical/Tribological Properties of the Corresponding Fiber-reinforced Epoxy Resin Composites

    Institute of Scientific and Technical Information of China (English)

    李瑞培; 李微微; 孟立; 李春阳

    2016-01-01

    为增强超高分子量聚乙烯(UHMWPE)纤维与环氧树脂(EP)基体之间的界面粘结强度,采用重铬酸钾溶液对 UHMWPE 纤维进行表面改性并制备 UHMWPE 纤维/EP 复合材料。结果表明,UHMWPE 纤维经液相氧化后表面刻蚀痕迹明显,表面粗糙度明显增加,结晶度增加了11.3%,与乙二醇的接触角减小了14.12°。与纯环氧树脂相比,纤维含量为0.4%的未改性 UHMWPE 纤维/EP 复合材料的拉伸强度降低18.04%,纤维含量为0.6%的液相氧化改性 UHMWPE 纤维/EP 复合材料的拉伸强度降低51.55%,未改性 UHMWPE(纤维含量0.5%)和液相氧化改性 UHMWPE(纤维含量0.4%)纤维/EP 复合材料的冲击强度分别提升了3.29%和4.39%。当纤维含量为0.3%时,液相氧化改性 UHMWPE 纤维/EP 复合材料的弯曲强度比纯环氧树脂增加6.55%,比未改性 UHMWPE纤维/EP 复合材料增加19%。当纤维含量由0增大到0.5%时,改性和未改性 UHMWPE 纤维/EP 复合材料的摩擦系数先增加后减小。%The effects of chromic acid liquid-phase oxidation treatment on ultra-high molecular weight polyethy-lene (UHMWPE)fibers were investigated to improve the interfacial adhesion between UHMWPE fibers and epoxy resin (EP).The UHMWPE fibers/EP composites were prepared with chromic acid-treated UHMWPE fibers.The results showed that the liquid-phase oxidation could effectively increase the fiber′s surface roughness,increase its crys-tallinity by 1 1.3% and reduce the contact angle with glycol by 14.12°.Compared with pure EP,the tensile strength of unmodified UHMWPE fibers/EP composite with a fiber content of 0.4wt% decreased by 18.04%,the tensile strength of liquid-phase oxidated UHMWPE fibers/EP composite with a fiber content of 0.6wt% decreased by 5 1.55%,the impact strength of unmodified UHMWPE (0.5wt% fiber content)and liquid-phase oxidated UHMWPE (0.4wt% fiber content)fibers/EP composite increased by 3.29% and 4.39%,respectively.Compared with the pure EP and

  4. Well-Defined Bilayered Molecular Cobrushes with Internal Polyethylene Blocks and ω-Hydroxyl-Functionalized Polyethylene Homobrushes

    KAUST Repository

    Zhang, Hefeng

    2016-02-15

    Novel well-defined bilayered molecular cobrushes with internal polyethylene blocks, P(PEcore-b-PScorona) (PE: polyethylene; PS: polystyrene), and ω-hydroxyl-functionalized polyethylene homobrushes, P(PE-OH), were synthesized through the macromonomer strategy. Two main steps were involved in the synthesis of the P(PEcore-b-PScorona) bilayered cobrushes: (i) formation of norbornyl-terminated macromonomer (Nor-PE-b-PS) by esterification of PS-b-PE-OH (combination of anionic polymerization, hydroboration, and polyhomologation) with 5-norbornene-2-carboxylic acid and (ii) ring-opening metathesis polymerization (ROMP) of Nor-PE-b-PS. The synthesis of P(PE-OH) was achieved by (i) hydroboration of tert-butyldimethylsilyl-protected allyl alcohol, followed by polyhomologation of dimethylsulfoxoniun methylide with the formed tri[3-(tert-butyldimethylsilyloxyl)propyl]borane initiator, oxidation/hydrolysis, and esterification of the TBDMS-O-PE-OH with 5-norbornene-2-carboxylic acid to afford the macromonomer TBDMS-O-PE-Nor, and (ii) ROMP of TBDMS-O-PE-Nor, followed by deprotection. Nuclear magnetic resonance spectroscopy (1H and 13C NMR) and high temperature gel permeation chromatography (HT-GPC) were used to characterize all macromonomers/molecular brushes and differential scanning calorimetry (DSC) to study the thermal properties. The molecular brush P(PE-b-PS) showed lower melting point (Tm) and better solubility in toluene than the corresponding macromonomer PS-b-PE-Nor. In the case of homobrushes, the thermal properties were strongly affected by the presence of the PE end-groups. © 2016 American Chemical Society.

  5. Radiative Cooling With Pigmented Polyethylene Foils

    Science.gov (United States)

    Niklasson, Gunnar A.; Eriksson, Tord S.

    1989-03-01

    Polyethylene foils containing a nonabsorbing pigment can be suitable for radiative cooling because of their high reflectance of solar radiation combined with a high transmittance in the atmospheric window region in the thermal infrared. We have studied the optical properties in the wavelength range 0.3-50 μm of extruded polyethylene foils containing various amounts of 0.23 μm diameter Ti02 particles. It appears that the foils can prevent heating of an underlying material, even when directly illuminated by the sun. The total transmittance and reflectance of the Ti02-polyethylene foils were compared with multiple scattering calculations. Lorenz-Mie theory was used to model the scattering and absorption of a single TiO2 sphere. The single scattering parameters were then introduced into the four flux theory, by which the transmittance and reflectance were calculated. We find a satisfactory agreement between theory and experiments in most cases.

  6. CONFORMATIONAL PROPERTIES OF STRETCHED POLYETHYLENE CHAIN

    Institute of Scientific and Technical Information of China (English)

    Lin-xi Zhang; De-lu Zhao

    2000-01-01

    When polyethylene chains are stretched, the chains are regarded as being confined in an infinite cylinder with decreasing diameter. The conformational properties of polyethylene chains confined in an infinite cylinder are investigated by using rotational isomeric state model. Using the average conformational energy and entropy and the average length, we can determine the elastic force f, or the fraction of the energy term to the total force fe/f, where fe=(б)/(б)/(б). Comparisons with experimental data are also made. The results of these microscopic calculations are discussed in terms of the macroscopic phenomena of rubber elasticity.

  7. Exact Topological Twistons in Crystalline Polyethylene

    CERN Document Server

    Ventura, E; Bazeia, D

    2000-01-01

    We investigate the presence of topological twistons in crystalline polyethylene. We describe crystalline polyethylene with a model that couples the torsional and longitudinal degrees of freedom of the polymeric chain by means of a system of two real scalar fields. This model supports topological twistons, which are described by exact and stable topological solutions that appear when the interaction between torsional and longitudinal fields is polynomial, containing up to the sixth power in the fields. We calculate the energy of the topological twiston, and the result is in very good agreement with the value obtained via molecular simulation.

  8. Performance of dodecyl amine functionalized graphene oxide/high-density polyethylene composites prepared by injection molding method%注塑型烷基化氧化石墨烯/高密度聚乙烯复合膜性能研究

    Institute of Scientific and Technical Information of China (English)

    张媛; 任鹏刚; Jan Wahlberg; 刘丹枫; 张晓亮

    2015-01-01

    通过注塑成型制备了均匀分散的十二烷基胺功能化氧化石墨烯(DA‐GO )/高密度聚乙烯(HDPE)纳米复合薄膜。X 射线衍射(XRD )研究表明,室温条件下DA 分子可与环氧基团发生亲核取代而接枝于GO表面。复合材料断口扫描显示,DA‐GO以剥离的形式均匀分散于 HDPE基体中。均匀分散的DA‐GO片层能有效提高HDPE复合膜的气体阻隔性能,当DA‐GO含量为05.%(质量分数)时,复合薄膜的透氧系数从纯 HDPE 的4.555×10-14 cm3 cm/(cm2· s · Pa)降低到18.30×10-14 cm3 cm/(cm2· s · Pa),阻氧性能提高了60%。此外,DA‐GO 片层的加入使HDPE的热稳定性明显提高。%The dodecyl amine (DA) functionalized graphene oxide (DA‐GO)/high‐density polyethylene (HDPE) membranes were prepared by injection molding method .X‐ray diffraction (XRD) showed that the DA could be successfully grafted onto the graphene oxide surface with uncleophilic substitution and amidation reaction .Mor‐phological analysis of nanocomposites showed that DA‐GO was homogeneously dispersed and fully exfoliated in the HDPE matrix ,which significantly improved the gas barring performance of HDPE .With 0 .5wt% RGO loading ,the permeability coefficient of O2 of DA‐GO/HDPE nanocomposite membranes decreased by 60% from 4 5.55 × 10-14 cm3cm/(cm2 · s · Pa) to 1 8.30 × 10-14 cm3cm/(cm2 · s · Pa) .Meanwhile ,the thermal stability of HDPE was also dramatically improved as a result of DA‐GO sheets .

  9. Polyethylene glycol-electrolyte solution (PEG-ES)

    Science.gov (United States)

    Polyethylene glycol-electrolyte solution (PEG-ES) is used to empty the colon (large intestine, bowel) before a colonoscopy ( ... Polyethylene glycol-electrolyte solution (PEG-ES) comes as a powder to mix with water and take by mouth. ...

  10. Structure and biocompatibility of ion beam modified polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Svorcik, V.; Rybka, V. [Institute of Chemical Technology, Prague (Czech Republic). Dept. of Solid State Engineering; Hnatowicz, V. [Academy of Sciences of Czech Republic, Rez (Czech Republic). Inst. of Nuclear Physics; Smetana, K. [Charles University, Prague (Czech Republic). First Faculty of Medicine

    1997-07-01

    Structural changes of polyethylene (PE), induced by irradiation with 40 keV Ar{sup +} ions at a fluence of 1 x 10{sup 12}-1 x 10{sup 15} cm{sup -2}, are characterized by different experimental methods and physical parameters of the modified PE are related to its biocompatibility. Production of oxidized structures and conjugated double bonds in the PE surface layer modified by the ion irradiation was proved using IR, UV-VIS spectroscopies and a Rutherford backscattering technique. The fusion of macrophages onto implants made of as-irradiated and chemically doped PE was studied in vivo. It was found that the free surface energy is not a decisive factor affecting the non-self-recognition of the modified PE by macrophages. The fusion of macrophages, however, was found to be different on the as-irradiated specimens and the specimens additionally doped with acrylic acid. (author).

  11. The alterations in high density polyethylene properties with gamma irradiation

    Science.gov (United States)

    Zaki, M. F.; Elshaer, Y. H.; Taha, Doaa. H.

    2017-10-01

    In the present investigation, high density polyethylene (HDPE) polymer has been used to study the alterations in its properties under gamma-irradiation. Physico-chemical properties have been investigated with different spectroscopy techniques, Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD), biocompatibility properties, as well as, mechanical properties change. The FT-IR analysis shows the formation of new band at 1716 cm-1 that is attributed to the oxidation of irradiated polymer chains, which is due to the formation of carbonyl groups (C˭O). XRD patterns show that a decrease in the crystallite size and increase in the Full Width at Half Maximum (FWHM). This means that the crystallinity of irradiated samples is decreased with increase in gamma dose. The contact angle measurements show an increase in the surface free energy as the gamma irradiation increases. The measurements of mechanical properties of irradiated HDPE samples were discussed.

  12. Electron beam induced modification of poly(ethylene terephthalate) films

    Energy Technology Data Exchange (ETDEWEB)

    Vasiljeva, I.V. [Technology Center RADIANT, 10, Kurchatova Str., 194223 St. Petersburg (Russian Federation)]. E-mail: radiant@skylink.spb.ru; Mjakin, S.V. [Technology Center RADIANT, 10, Kurchatova Str., 194223 St. Petersburg (Russian Federation); Makarov, A.V. [St.-Petersburg State University of Cinema and Television, 13, ul. Pravdy, 191126 St. Petersburg (Russian Federation); Krasovsky, A.N. [St.-Petersburg State University of Cinema and Television, 13, ul. Pravdy, 191126 St. Petersburg (Russian Federation); Varlamov, A.V. [St.-Petersburg State University of Cinema and Television, 13, ul. Pravdy, 191126 St. Petersburg (Russian Federation)

    2006-10-15

    Electron beam processing of poly(ethylene terephthalate) (PET) films is found to promote significant changes in the melting heat, intrinsic viscosity and polymer film-liquid (water, isooctane and toluene) boundary surface tension. These properties are featured with several maximums depending on the absorbed dose and correlating with the modification of PET surface functionality. Studies using adsorption of acid-base indicators and IR-spectroscopy revealed that the increase of PET surface hydrophilicity is determined by the oxidation of methylene and methyne groups. Electron beam treatment of PET films on the surface of N-vinylpyrrolidone aqueous solution provided graft copolymerization with this comonomer at optimum process parameters (energy 700 keV, current 1 mA, absorbed dose 50 kGy)

  13. Radiation cross-linking in ultra-high molecular weight polyethylene for orthopaedic applications

    OpenAIRE

    Oral, Ebru; Muratoglu, Orhun K.

    2007-01-01

    The motivation for radiation cross-linking of ultra-high molecular weight polyethylene (UHMWPE) is to increase its wear resistance to be used as bearing surfaces for total joint arthroplasty. However, radiation also leaves behind long-lived residual free radicals in this polymer, the reactions of which can detrimentally affect mechanical properties. In this review, we focus on the radiation cross-linking and oxidative stability of first and second generation highly cross-linked UHMWPEs develo...

  14. Radiation-crosslinked polyethylene for wire and cable applications

    Science.gov (United States)

    Ueno, Keiji; Uda, Ikujiro; Tada, Shotaro

    Polyethylene is used as an insulation material for wires and cables because of its excellent electrical properties. Polyethylene is also a typical irradiated crosslinked polymer. The characteristics of irradiated polyethylene, the effects of density, molecular weight and so on, were studied.

  15. 21 CFR 178.3760 - Polyethylene glycol (400) monolaurate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyethylene glycol (400) monolaurate. 178.3760... SANITIZERS Certain Adjuvants and Production Aids § 178.3760 Polyethylene glycol (400) monolaurate. Polyethylene glycol (400) monolaurate containing not more than 0.1 percent by weight of ethylene...

  16. Comparison of Polyethylene Glycol-Electrolyte Solution vs Polyethylene Glycol-3350 for the Treatment of Fecal Impaction in Pediatric Patients

    OpenAIRE

    Boles, Erin E.; Gaines, Cameryn L.; Tillman, Emma M.

    2015-01-01

    OBJECTIVES: The objective of this study was to evaluate the safety and efficacy of polyethylene glycol-electrolyte solution vs polyethylene glycol-3350 for the treatment of fecal impaction in pediatric patients.

  17. Three Year RSA Evaluation of Vitamin E Diffused Highly Cross-linked Polyethylene Liners and Cup Stability

    DEFF Research Database (Denmark)

    Sillesen, Nanna H; Greene, Meridith E; Nebergall, Audrey K;

    2015-01-01

    Vitamin E diffusion into highly cross-linked polyethylene (E-XLPE) is a method for enhancing oxidative stability of acetabular liners. The purpose of this study was to evaluate in vivo penetration of E-XLPE using radiostereometric analysis (RSA). Eighty-four hips were recruited into a prospective...

  18. Neutron Compton scattering studies of stretched polyethylene

    CERN Document Server

    Gabrys, B J; Mayers, J; Kalhoro, M S

    2002-01-01

    The mean kinetic energy of hydrogen and carbon atoms in unstretched and stretched polyethylene samples has been measured by neutron Compton scattering. The vibrational frequencies of the ground state and torsional energies have been calculated and compared with the existing data and calculations. The results obtained on deuterated and non-deuterated samples are compared. (orig.)

  19. Polyethylene glycol-grafted polystyrene particles

    NARCIS (Netherlands)

    Meng, Fenghua; Engbers, Gerard H.M.; Feijen, Jan

    2004-01-01

    Densely pegylated particles that can serve as a model system for artificial cells were prepared by covalently grafting amino polyethylene glycol (PEG, molecular weight 3400 or 5000) onto carboxyl polystyrene particles (PS-COOH) using carbodiimide chemistry. PEG-modified particles (PS-PEG) were chara

  20. Evaluation of Paulownia elongata wood polyethylene composites

    Science.gov (United States)

    Paulownia wood flour (PWF), a byproduct of milling lumber, was employed as a bio-filler and blended with high density polyethylene (HDPE) via extrusion. Paulownia wood (PW) shavings were milled through a 1-mm screen then separated via shaking into various particle fractions using sieves (#30 - < #2...

  1. Dynamic compressive behavior of foamed polyethylene film

    Directory of Open Access Journals (Sweden)

    Tateyama Kohei

    2015-01-01

    Full Text Available The foamed film as the shock absorption material has attracted much attention because it is thin (100 μm ∼ 400 μm and has a closed cell structure. However, the dynamic mechanical properties have not been reported in the foamed film. The purpose of this study is to elucidate the compressive behavior of the foamed polyethylene film at the wide strain rate range. First, the new compressive test apparatus for the dynamic strain rate, the drop-weight testing machine with opposed load cell, was developed, which can be also evaluated the dynamic stress equilibrium of the specimen. It is confirmed that the compressive flow stress increased with increasing the strain rate, regardless of the film thickness. The foamed polyethylene film has the high strain rate sensitivity in the quasi-static deformation. On the other hand, there is almost no change of the strain rate sensitivity in the dynamic and the impact deformation. In order to investigate the mechanism of strain rate dependence, the foamed polyethylene film was observed by X-ray computed tomography scanner before and after compressive test. The fracture of the closed cell only occurred in the quasi-static deformation. It was clarified that the strain rate sensitivity of the foamed film depends strongly on that of the construction material, polyethylene.

  2. The effect of chromic acid treatment on the mechanical and tribological properties of aramid fibre reinforced ultra-high molecular weight polyethylene composite

    NARCIS (Netherlands)

    Hofste, JM; Pennings, AJ; Schut, J.A.

    1998-01-01

    Surface oxidation of ultra-high molecular weight polyethylene (UHMWPE) powder has an influence on the mixing procedure of chopped fibres and UHMWPE powder. Due to this oxidation hydrogen bonds can be formed between the fibres and powder particles, leading to a more homogeneous fibre-powder mixture.

  3. Well-Defined Polyethylene-Based Random, Block, and Bilayered Molecular Cobrushes

    KAUST Repository

    Zhang, Hefeng

    2015-06-09

    Novel well-defined polyethylene-based random, block, and bilayered molecular cobrushes were synthesized through the macromonomer strategy. Two steps were involved in this approach: (i) synthesis of norbornyl-terminated macromonomers of polyethylene (PE), polycaprolactone (PCL), poly(ethylene oxide) (PEO), and polystyrene (PS), as well as polyethylene-b-polycaprolactone (PE-b-PCL), by esterification of the hydroxyl-terminated precursors (PE, PCL, PEO, PS, and PE-b-PCL) with 5-norbornene-2-carboxylic acid and (ii) ring-opening metathesis (co)polymerization of the resulting macromonomers to afford the PE-based molecular cobrushes. The PE-macromonomers were synthesized by polyhomologation of dimethylsulfoxonium methylide, while the others by anionic polymerization. Proton nuclear magnetic resonance spectroscopy (1H NMR) and high-temperature gel permeation chromatography (HT-GPC) were used to imprint the molecular characteristics of all macromonomers and molecular brushes and differential scanning calorimetry (DSC) for the thermal properties. The bilayered molecular cobrushes of P(PE-b-PCL) adopt a wormlike morphology on silica wafer as visualized by atomic force microscopy (AFM). © 2015 American Chemical Society.

  4. Polyethylene sterilization and production affects wear in total hip arthroplasties.

    Science.gov (United States)

    Faris, Philip M; Ritter, Merrill A; Pierce, Andrew L; Davis, Kenneth E; Faris, Gregory W

    2006-12-01

    Production and package sterilization techniques for the polyethylene used in acetabular components for total hip arthroplasties are known to affect wear. We considered three combinations of techniques: sterilization by radiation in inert gas with isostatically molded polyethylene, in inert gas and ram-extruded polyethylene, and in air with extruded polyethylene. The intent of this study was to confirm that molded polyethylene and polyethylene radiated in inert environments reduce wear rates in vivo, to determine the combination of methods with the least wear, and to determine how much variance in wear is attributable to these methods. We reviewed 150 consecutive total hip arthroplasties done in 133 patients using 28-mm cobalt-chrome femoral heads and polyethylene-lined, titanium, ring-locked acetabular components. The least wear occurred in gamma inert-molded polyethylene components. The mean volumetric wear rates were 52.12 mm3/year for gamma inert-molded, 62.32 mm3/year for gamma inert-extruded, and 66.09 mm3/year for gamma air-extruded polyethylene components. Relative risk assessment found gamma air-extruded and gamma inert-extruded polyethylene components to wear 16% and 11% more than gamma inert-molded polyethylene components, respectively. Gender, body mass index, and age accounted for the greatest amount of the explained variance in volumetric wear (57.5%, 21.6%, and 14.4, respectively), followed by angle of wear (3.4%), and sterilization and production technique (3.2%).

  5. Enthalpy of dilution of poly(ethylene oxide) in trichloromethane

    Science.gov (United States)

    Wohlfarth, Ch.

    This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

  6. Optimization of process and solution parameters in electrospinning polyethylene oxide

    CSIR Research Space (South Africa)

    Jacobs, V

    2011-11-01

    Full Text Available , applied voltage and polyallylamine hydrochloride (PAH) concentration in the spinning solution and its influence on nanofiber diameter. The selected parameters were varied at three levels using Box and Behnken factorial design. The interaction effect...

  7. Hydrophilic segmented block copolymers based on poly(ethylene oxide)

    NARCIS (Netherlands)

    Husken, D.

    2006-01-01

    Segmented block copolymers consist of alternating flexible segments and crystallisable rigid segments. The flexible segments have a low glass transition temperature and are used to obtain flexible materials. The rigid segments can crystallise and act as thermal-reversible physical crosslinks, giving

  8. Enzymatic hydrolysis of poly(ethylene furanoate).

    Science.gov (United States)

    Pellis, Alessandro; Haernvall, Karolina; Pichler, Christian M; Ghazaryan, Gagik; Breinbauer, Rolf; Guebitz, Georg M

    2016-10-10

    The urgency of producing new environmentally-friendly polyesters strongly enhanced the development of bio-based poly(ethylene furanoate) (PEF) as an alternative to plastics like poly(ethylene terephthalate) (PET) for applications that include food packaging, personal and home care containers and thermoforming equipment. In this study, PEF powders of various molecular weights (6, 10 and 40kDa) were synthetized and their susceptibility to enzymatic hydrolysis was investigated for the first time. According to LC/TOF-MS analysis, cutinase 1 from Thermobifida cellulosilytica liberated both 2,5-furandicarboxylic acid and oligomers of up to DP4. The enzyme preferentially hydrolyzed PEF with higher molecular weights but was active on all tested substrates. Mild enzymatic hydrolysis of PEF has a potential both for surface functionalization and monomers recycling. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Polyethylene imine-metal salt solid electrolyte

    Science.gov (United States)

    Davis, G. T.; Chiang, C. K.; Takahashi, T.

    1985-02-01

    This research pertains to the development of new solid battery electrolytes. An object of this invention is to provide polymeric electrolytes using a wider variety of metal salts. These and other objects of this invention are accomplished by providing: (1) a solid polymer electrolyte comprising: a matrix of linear poly(ethylene amine) having the formula (-CH2CH2NH-)n; and (2) a metal salt which is LiI, LiClO4, NaI, NaBr, KI, CsSCN, AgNO3, CuCl1, CoCl2, or Mg(ClO4)2, wherein the salt is dissolved in and distributed throughout the poly(ethylene amine) matrix and from more than zero to 0.10 moles of salt are used per mole of monomer repeat unit, (-CH2CH2NH-).

  10. Hydration of polyethylene glycol-grafted liposomes.

    OpenAIRE

    Tirosh, O; Barenholz, Y.; Katzhendler, J; Priev, A

    1998-01-01

    This study aimed to characterize the effect of polyethylene glycol of 2000 molecular weight (PEG2000) attached to a dialkylphosphatidic acid (dihexadecylphosphatidyl (DHP)-PEG2000) on the hydration and thermodynamic stability of lipid assemblies. Differential scanning calorimetry, densitometry, and ultrasound velocity and absorption measurements were used for thermodynamic and hydrational characterization. Using a differential scanning calorimetry technique we showed that each molecule of PEG...

  11. CHEMICAL MORPHOLOGY IN GRAFTING ACRYLAMIDE TO POLYETHYLENE

    Institute of Scientific and Technical Information of China (English)

    S. Termnak; K. Sintasanai; T. Amomsakchai; T. Nipithakul; D. Triampo

    2008-01-01

    The scanning force microscopy (SFM)/chemical force microscopy (CFM) were used to study the growth of grafted polyacrylamide (PAM) chains onto polyethylene (PE)-film with varying grafting time. Results from the CFM reveal reduced interaction between the probe and areas with grafted-PAM on the surface. The topography and the friction trace-minus-retrace (TMR) images are complementary to one another resulting from the reduced interaction of the probe that has specificity to chemical domains.

  12. Thermal Analyse sof Cross-Linked Polyethylene

    Directory of Open Access Journals (Sweden)

    Radek Polansky

    2007-01-01

    Full Text Available The paper summarizes results obtained during the structural analyses measurements (Differential Scanning Calorimetry DSC, Thermogravimetry TG, Thermomechanical analysis TMA and Fourier transform infrared spectroscopy FT-IR. The samples of cross-linked polyethylene cable insulation were tested via these analyses. The DSC and TG were carried out using simultaneous thermal analyzer TA Instruments SDT Q600 with connection of Fourier transform infrared spectrometer Nicolet 380. Thermomechanical analysis was carried out by TMA Q400EM TA Instruments apparatus.

  13. Supercritical CO2 impregnation of polyethylene components for medical purposes

    Directory of Open Access Journals (Sweden)

    Gamse Thomas

    2007-01-01

    Full Text Available Modem hip and knee endoprosthesis are produced in titanium and to reduce the friction at the contact area polymer parts, mainly ultra-high molecular weight polyethylene (UHMW-PE, are installed. The polyethylene is impregnated with a-tocopherol (vitamin E before processing for remarkable decrease of oxidative degradation. Cross linked UHMW-PE offers much higher stability, but a-tocopherol cannot be added before processing, because a-tocopherol hinders the cross linking process accompanied by a heavy degradation of the vitamin. The impregnation of UHMW-PE with a-tocopherol has to be performed after the cross linking process and an accurate concentration has to be achieved over the cross section of the whole material. In the first tests UHMW-PE-cubes were stored in pure a-tocopherol under inert atmosphere at temperatures from 100 to 150 °C resulting in a high mass fraction of a-tocopherol in the edge zones and no constant concentration over the cross section. For better distribution and for regulating the mass fraction of a-tocopherol in the cross linked UHMW-PE material supercritical CO2 impregnation tests were investigated. Again UHMW-PE-cubes were impregnated in an autoclave with a-tocopherol dissolved in supercritical CO2 at different pressures and temperatures with variable impregnation times and vitamin E concentrations. Based on the excellent results of supercritical CO2 impregnation standard hip and knee cups were stabilized nearly homogeneously with varying mass fraction of a-tocopherol.

  14. Phase behaviour of polyethylene knotted ring chains

    Institute of Scientific and Technical Information of China (English)

    Wen Xiao-Hui; Zhang Lin-Xi; Xia A-Gen; Chen Hong-Ping

    2011-01-01

    The phase behaviour of polyethylene knotted ring chains is investigated by using molecular dynamics simulations.In this paper, we focus on the collapse of the polyethylene knotted ring chain, and also present the results of linear and ring chains for comparison. At high temperatures, a fully extensive knot structure is observed. The mean-square radius of gyration per bond〈S2〉/(Nb2)and the shape factor(δ*)depend on not only the chain length but also the knot type.With temperature decreasing, chain collapse is observed, and the collapse temperature decreases with the chain length increasing. The actual collapse transition can be determined by the specific heat capacity Cv, and the knotted ring chain undergoes gas-liquid-solid-like transition directly. The phase transition of a knotted ring chain is only one-stage collapse, which is different from the polyethylene linear and ring chains. This investigation can provide some insights into the statistical properties of knotted polymer chains.

  15. Enhanced adherence of mouse fibroblast and vascular cells to plasma modified polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Reznickova, Alena, E-mail: alena.reznickova@vscht.cz [Department of Solid State Engineering, Institute of Chemical Technology Prague, 166 28 Prague 6 (Czech Republic); Novotna, Zdenka, E-mail: zdenka1.novotna@vscht.cz [Department of Solid State Engineering, Institute of Chemical Technology Prague, 166 28 Prague 6 (Czech Republic); Kolska, Zdenka [Faculty of Science, J.E. Purkyně University, 400 96 Usti nad Labem (Czech Republic); Kasalkova, Nikola Slepickova [Department of Solid State Engineering, Institute of Chemical Technology Prague, 166 28 Prague 6 (Czech Republic); Rimpelova, Silvie [Department of Biochemistry and Microbiology, Institute of Chemical Technology Prague, 166 28 Prague 6 (Czech Republic); Svorcik, Vaclav [Department of Solid State Engineering, Institute of Chemical Technology Prague, 166 28 Prague 6 (Czech Republic)

    2015-07-01

    Since the last decade, tissue engineering has shown a sensational promise in providing more viable alternatives to surgical procedures for harvested tissues, implants and prostheses. Biomedical polymers, such as low-density polyethylene (LDPE), high-density polyethylene (HDPE) and ultra-high molecular weight polyethylene (UHMWPE), were activated by Ar plasma discharge. Degradation of polymer chains was examined by determination of the thickness of ablated layer. The amount of an ablated polymer layer was measured by gravimetry. Contact angle, measured by goniometry, was studied as a function of plasma exposure and post-exposure aging times. Chemical structure of modified polymers was characterized by angle resolved X-ray photoelectron spectroscopy. Surface chemistry and polarity of the samples were investigated by electrokinetic analysis. Changes in surface morphology were followed using atomic force microscopy. Cytocompatibility of plasma activated polyethylene foils was studied using two distinct model cell lines; VSMCs (vascular smooth muscle cells) as a model for vascular graft testing and connective tissue cells L929 (mouse fibroblasts) approved for standardized material cytotoxicity testing. Specifically, the cell number, morphology, and metabolic activity of the adhered and proliferated cells on the polyethylene matrices were studied in vitro. It was found that the plasma treatment caused ablation of the polymers, resulting in dramatic changes in their surface morphology and roughness. ARXPS and electrokinetic measurements revealed oxidation of the polymer surface. It was found that plasma activation has a positive effect on the adhesion and proliferation of VSMCs and L929 cells. - Highlights: • Plasma activation of LDPE, HDPE and UHMWPE • Study of surface properties by several techniques: ARXPS, AFM, zeta-potential, and goniometry • Investigation of adhesion and spreading of vascular smooth muscle cells (VSMCs) and mouse fibroblasts (L929)

  16. Wear of sequentially enhanced 9-Mrad polyethylene in 10 million cycle knee simulation study.

    Science.gov (United States)

    Tsukamoto, Riichiro; Williams, Paul Allen; Shoji, Hiromu; Hirakawa, Kazuo; Yamamoto, Kengo; Tsukamoto, Mikiko; Clarke, Ian C

    2008-07-01

    Highly crosslinked polyethylene (HXPE) has been shown to be effective in reducing wear in total hip replacements. HXPE has not found widespread use in TKR, because the crosslinking inevitably leads to reductions in critical properties such as toughness and fatigue strength. Sequentially enhanced crosslinking (SXPE) have been suggested for improved wear resistance for tibial inserts with maintenance of mechanical properties and anticipated high oxidation resistance superior to conventional polyethylene (XLPE). We compared the wear of SXPE (9Mrad) to XLPE inserts (3Mrad) to 10 million cycles. Triathlon femoral condyles were identical in both. This is the first wear study of SXPE inserts. According to the power law relating irradiation dose to wear of XLPE inserts, wear of 9 Mrad inserts should be reduced by 70% compared to 3Mrad controls. The wear rates of the SXPE inserts were reduced by 86% at 10 million cycles duration, somewhat greater than predicted. The one prior investigation by the manufacturer reported a 79% wear reduction for SXPE compared to controls in a 5 million cycle simulator study in knee design and test parameters. There were important differences between the two studies. Nevertheless there clearly appeared to be a major benefit for sequentially enhanced polyethylene in tibial inserts. This combined wear reduction of 80-85% with improved oxidation resistance and retention of mechanical properties may prove beneficial for active patients who may otherwise risk high wear rates over many years of use.

  17. Degradation of polyethylene glycol by Fenton reaction: a comparative study.

    Science.gov (United States)

    Haseneder, R; Fdez-Navamuel, B; Härtel, G

    2007-01-01

    Photochemical advanced oxidation processes (AOPs) utilising different Fenton systems were investigated in laboratory-scale experiments for the degradation of polyethylene glycol (PEG). The results of the study showed that the degradation rate of PEG was strongly accelerated by the homogeneous system, and this proved to be advantageous in comparison to the heterogeneous system. Between Fenton and photo-Fenton heterogeneous systems, the photo-Fenton process reached the highest removal rate of the organic compound, due to the enhanced reduction efficiency of Fe(III) to Fe(II) under UV-irradiation. The oxidation rate in the heterogeneous system was investigated using varying different parameters, such as the pH value, the concentration of hydrogen peroxide and the amount of Fe(OH)3 as the catalyst. For the homogeneous Fenton system the rate of degradation is significantly higher. At the same time of operation the elimination rates can be found to be 30% over the rates of the heterogeneous system. Optimising the typical influence parameters mentioned before, a degradation of about 93% of PEG can be achieved by using the homogeneous Fenton system.

  18. Híbridos de poli(oxido de etileno-b-amida-6 e ZrO2 sol-gel: preparação, caracterização e aplicação em processos de separação por membranas Hybrids of poly(ethylene oxide-b-amide-6 and ZrO2 sol-gel: preparation, characterization and application in membrane separation processes

    Directory of Open Access Journals (Sweden)

    Rita A. Zoppi

    2000-06-01

    Full Text Available Híbridos constituídos de poli(óxido de etileno-b-amida-6, PEBAX, e óxido de zircônio foram preparados a partir da hidrólise e condensação do tetraisopropóxido de zircônio em solução contendo o polímero orgânico dissolvido. Estes foram caracterizados por termogravimetria, calorimetria diferencial de varredura, espectroscopia na região do infravermelho e microscopia eletrônica. Os resultados obtidos mostraram que a incorporação da fase inorgânica parece promover a degradação do polímero orgânico. Membranas compostas constituídas de um suporte poroso de poli(fluoreto de vinilideno, PVDF, e uma camada filtrante de PEBAX/ZrO2 foram preparadas e caracterizadas por microscopia eletrônica. Foram realizados ensaios de permeação de água e de soluções aquosas contendo poli(etileno glicol de diferentes massas molares. Para determinar a rejeição de fosfato, foram realizados ensaios de permeação de uma solução aquosa de KH2PO4. Independente da composição da camada filtrante, foram obtidos valores de rejeição de fosfato da ordem de 80%.Hybrid films based on poly(ethylene oxide-b-amide-6, PEBAX, and zirconium oxide were prepared by hydrolysis and condensation of zirconium tetraisopropoxide in a 3wt% PEBAX/n-butanol solution. Films were characterized by thermogravimetric analysis, differential scanning calorimetry, infrared spectroscopy and electron microscopy. The results showed that the incorporation of the inorganic phase promoted the organic polymer degradation. Composite membranes constituted by a porous support of poly(vinylidene fluoride, PVDF, covered with a PEBAX/ZrO2 filter layer were prepared and characterized by electron microscopy. Tests including the permeation of water and aqueous solutions of poly(ethylene glycol with different molecular weight were performed. Phosphate retention was also determined by permeation tests of a KH2PO4 aqueous solution. Regardless of the filter layer composition, phosphate

  19. Highly Cross-Linked Versus Conventional Polyethylene in Posterior-Stabilized Total Knee Arthroplasty at a Mean 5-Year Follow-up.

    Science.gov (United States)

    Meneghini, R Michael; Lovro, Luke R; Smits, Shelly A; Ireland, Philip H

    2015-10-01

    Concerns of highly cross-linked polyethylene (XLPE) in total knee arthroplasty (TKA) exist regarding fatigue resistance and oxidation, particularly in posterior-stabilized (PS) designs. A prospective cohort study of 114 consecutive PS TKAs utilized conventional polyethylene in 50 knees and second-generation annealed XLPE in 64 TKAs. Clinical (Short-Form 36, Knee Society Scores, and LEAS) and radiographic outcomes were evaluated at a mean of 5 years in 103 TKAs. Mean KSS scores were 12 points higher (P=0.01) and SF-36 physical function subset 14 points higher (P=0.005) in the XLPE group. There was no radiographic osteolysis or mechanical failure related to the tibial polyethylene in either group. At 5-year follow-up, no deleterious effects related to highly cross-linked posterior stabilized tibial polyethylene inserts were observed.

  20. Influence of the irradiation conditions on the effect of radiation on polyethylene

    Directory of Open Access Journals (Sweden)

    BOJANA SECEROV

    2004-12-01

    Full Text Available Two types of polyethylene, low density (LDPE and high density (HDPE, as well as low density polyethylene containing an antioxidant were subjected to g-irradiation in the presence of air and in water. The irradiated polymers were studied using IR spectrophotometric analysis. The radiation induced oxidative degradation was followed through the formation of oxygen containing groups by the development of bands in the 1850–1650 cm-1 region and double bonds formation by the development of bands in the 1050–850 cm-1 region. The crosslinking efficiency was determined by measuring the gel content by extraction with xylene. The radiation induced changes in the molecular structure, evolution of oxygen containing species and formation, of vinyl double bonds as well as of the crosslinking efficiency are discussed in terms of the properties of the polymers in an electric field of low strength.

  1. Mechanisms for covalent immobilization of horseradish peroxi-dase on ion beam treated polyethylene

    CERN Document Server

    Kondyurin, Alexey V; Tilley, Jennifer M R; Nosworthy, Neil J; Bilek, Marcela M M; McKenzie, David R

    2011-01-01

    The mechanism that provides the observed strong binding of biomolecules to polymer sur-faces modified by ion beams is investigated. The surface of polyethylene (PE) was modified by plasma immersion ion implantation with nitrogen ions. Structure changes including car-bonization and oxidation were observed in the modified surface layer of PE by Raman spec-troscopy, FTIR ATR spectroscopy, atomic force microscopy, surface energy measurement and XPS spectroscopy. An observed high surface energy of the modified polyethylene was attributed to the presence of free radicals on the surface. The surface energy decay with stor-age time after PIII treatment was explained by a decay of the free radical concentration while the concentration of oxygen-containing groups increased with storage time. Horseradish per-oxidase was covalently attached onto the modified PE surface. The enzymatic activity of co-valently attached protein remained high. A mechanism based on the covalent attachment by the reaction of protein with free r...

  2. C1 Polymerization: a unique tool towards polyethylene-based complex macromolecular architectures

    KAUST Repository

    Wang, De

    2017-05-09

    The recent developments in organoborane initiated C1 polymerization (chain grows by one atom at a time) of ylides opens unique horizons towards well-defined/perfectly linear polymethylenes (equivalent to polyethylenes, PE) and PE-based complex macromolecular architectures. The general mechanism of C1 polymerization (polyhomologation) involves the formation of a Lewis complex between a methylide (monomer) and a borane (initiator), followed by migration/insertion of a methylene into the initiator and after oxidation/hydrolysis to afford OH-terminated polyethylenes. This review summarizes efforts towards conventional and newly discovered borane-initiators and ylides (monomers), as well as a combination of polyhomologation with other polymerization methods. Initial efforts dealing with C3 polymerization and the synthesis of the first C1/C3 copolymers are also given. Finally, some thoughts for the future of these polymerizations are presented.

  3. The "New Polyethylene Glycol Dilemma": Polyethylene Glycol Impurities and Their Paradox Role in mAb Crystallization.

    Science.gov (United States)

    Hildebrandt, Christian; Joos, Lea; Saedler, Rainer; Winter, Gerhard

    2015-06-01

    Polyethylene glycols (PEG) represent the most successful and frequently applied class of excipients used for protein crystallization. PEG auto-oxidation and formation of impurities such as peroxides and formaldehydes that foster protein drug degradation is known. However, their effect on mAb crystallization has not been studied in detail before. During the present study, a model IgG1 antibody (mAb1) was crystallized in PEG solutions. Aggregate formation was observed during crystallization and storage that was ascribed to PEG degradation products. Reduction of peroxide and formaldehyde levels prior to crystallization by vacuum and freeze-drying was investigated for its effect on protein degradation. Vacuum drying was superior in removal of peroxides but inferior in reducing formaldehyde residues. Consequently, double purification allowed extensive removal of both impurities. Applying of purified PEG led to 50% lower aggregate fractions. Surprisingly, PEG double purification or addition of methionine prior to crystallization prevented crystal formation. With increased PEG concentration or spiking with peroxides and formaldehydes, crystal formation could be recovered again. With these results, we demonstrate that minimum amounts of oxidizing impurities and thus in consequence chemically altered proteins are vital to initiate mAb1 crystallization. The present study calls PEG as good precipitant for therapeutic biopharmaceuticals into question.

  4. Polymerization of ethylene oxide using yttrium isopropoxide

    NARCIS (Netherlands)

    Choi, Young K.; Stevels, W.M.; Ankone, Martinus J.K.; Dijkstra, Pieter J.; Kim, Sung W.; Feijen, Jan

    1996-01-01

    Well defined poly(ethylene oxide)s were prepared using yttrium isopropoxide as an initiator. End group analysis using 1H- and 13C NMR spectroscopy revealed that only polymers with isopropyl ether and hydroxyl end groups were produced. The molecular weight is controlled by the initial amount of

  5. Antibacterial performance of alginic acid coating on polyethylene film

    National Research Council Canada - National Science Library

    Karbassi, Elika; Asadinezhad, Ahmad; Lehocký, Marian; Humpolíček, Petr; Vesel, Alenka; Novák, Igor; Sáha, Petr

    2014-01-01

    Alginic acid coated polyethylene films were examined in terms of surface properties and bacteriostatic performance against two most representative bacterial strains, that is, Escherichia coli and Staphylococcus aureus...

  6. Surface pre-treatment for barrier coatings on polyethylene terephthalate

    Science.gov (United States)

    Bahre, H.; Bahroun, K.; Behm, H.; Steves, S.; Awakowicz, P.; Böke, M.; Hopmann, Ch; Winter, J.

    2013-02-01

    Polymers have favourable properties such as light weight, flexibility and transparency. Consequently, this makes them suitable for food packaging, organic light-emitting diodes and flexible solar cells. Nonetheless, raw plastics do not possess sufficient barrier functionality against oxygen and water vapour, which is of paramount importance for most applications. A widespread solution is to deposit thin silicon oxide layers using plasma processes. However, silicon oxide layers do not always fulfil the requirements concerning adhesion and barrier performance when deposited on films. Thus, plasma pre-treatment is often necessary. To analyse the influence of a plasma-based pre-treatment on barrier performance, different plasma pre-treatments on three reactor setups were applied to a very smooth polyethylene terephthalate film before depositing a silicon oxide barrier layer. In this paper, the influence of oxygen and argon plasma pre-treatments towards the barrier performance is discussed examining the chemical and topological change of the film. It was observed that a short one-to-ten-second plasma treatment can reduce the oxygen transmission rate by a factor of five. The surface chemistry and the surface topography change significantly for these short treatment times, leading to an increased surface energy. The surface roughness rises slowly due to the development of small spots in the nanometre range. For very long treatment times, surface roughness of the order of the barrier layer's thickness results in a complete loss of barrier properties. During plasma pre-treatment, the trade-off between surface activation and roughening of the surface has to be carefully considered.

  7. Patterned functional carbon fibers from polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, Marcus A [ORNL; Saito, Tomonori [ORNL; Brown, Rebecca H [ORNL; Kumbhar, Amar S [University of North Carolina, Chapel Hill; Naskar, Amit K [ORNL

    2012-01-01

    Patterned, continuous carbon fibers with controlled surface geometry were produced from a novel melt-processible carbon precursor. This portends the use of a unique technique to produce such technologically innovative fibers in large volume for important applications. The novelties of this technique include ease of designing and fabricating fibers with customized surface contour, the ability to manipulate filament diameter from submicron scale to a couple of orders of magnitude larger scale, and the amenable porosity gradient across the carbon wall by diffusion controlled functionalization of precursor. The geometry of fiber cross-section was tailored by using bicomponent melt-spinning with shaped dies and controlling the melt-processing of the precursor polymer. Circular, trilobal, gear-shaped hollow fibers, and solid star-shaped carbon fibers of 0.5 - 20 um diameters, either in self-assembled bundle form, or non-bonded loose filament form, were produced by carbonizing functionalized-polyethylene fibers. Prior to carbonization, melt-spun fibers were converted to a char-forming mass by optimizing the sulfonation on polyethylene macromolecules. The fibers exhibited distinctly ordered carbon morphologies at the outside skin compared to the inner surface or fiber core. Such order in carbon microstructure can be further tuned by altering processing parameters. Partially sulfonated polyethylene-derived hollow carbon fibers exhibit 2-10 fold surface area (50-500 m2/g) compared to the solid fibers (10-25 m2/g) with pore sizes closer to the inside diameter of the filaments larger than the sizes on the outer layer. These specially functionalized carbon fibers hold promise for extraordinary performance improvements when used, for example, as composite reinforcements, catalyst support media, membranes for gas separation, CO2 sorbents, and active electrodes and current collectors for energy storage applications.

  8. Polyethylene glycols (PEG) and related structures

    DEFF Research Database (Denmark)

    Wenande, Emily; Kroigaard, Mogens; Mosbech, Holger

    2015-01-01

    We describe hypersensitivity to polyethylene glycols (PEGs), with cross-reactivity to a structural analog, polysorbate 80, in a 69-year-old patient with perioperative anaphylaxis and subsequent, severe anaphylactic reactions to unrelated medical products. PEGs and PEG analogs are prevalent...... in the perioperative setting, contained in a wide range of products seldom suspected of causing hypersensitivity reactions and thus rarely documented in surgical/anesthetic records. We suggest routine testing for PEGs after perioperative anaphylaxis because exposure to these polymers often is significant....... Comprehensive brand name documentation on the anesthetic chart of all product exposures is central to identifying the responsible allergen....

  9. Thermoviscoelastic models for polyethylene thin films

    DEFF Research Database (Denmark)

    Li, Jun; Kwok, Kawai; Pellegrino, Sergio

    2016-01-01

    This paper presents a constitutive thermoviscoelastic model for thin films of linear low-density polyethylene subject to strains up to yielding. The model is based on the free volume theory of nonlinear thermoviscoelasticity, extended to orthotropic membranes. An ingredient of the present approach...... is that the experimentally inaccessible out-of-plane material properties are determined by fitting the model predictions to the measured nonlinear behavior of the film. Creep tests, uniaxial tension tests, and biaxial bubble tests are used to determine the material parameters. The model has been validated experimentally...

  10. Polyethylene terephthalate thin films; a luminescence study

    Science.gov (United States)

    Carmona-Téllez, S.; Alarcón-Flores, G.; Meza-Rocha, A.; Zaleta-Alejandre, E.; Aguilar-Futis, M.; Murrieta S, H.; Falcony, C.

    2015-04-01

    Polyethylene Terephthalate (PET) films doped with Rare Earths (RE3+) have been deposited on glass by spray pyrolysis technique at 240 °C, using recycled PET and (RE3+) chlorides as precursors. Cerium, terbium, dysprosium and europium were used as dopants materials, these dopants normally produce luminescent emissions at 450, 545, 573 and 612 nm respectively; the doped films also have light emissions at blue, green, yellow and red respectively. All RE3+ characteristic emissions were observed at naked eyes. Every deposited films show a high transmission in the visible range (close 80% T), films surfaces are pretty soft and homogeneous. Films thickness is around 3 μm.

  11. Sintering of ultra high molecular weight polyethylene

    Indian Academy of Sciences (India)

    Sangeeta Hambir; J P Jog

    2000-06-01

    Ultra high molecular weight polyethylene (UHMWPE) is a high performance polymer having low coefficient of friction, good abrasion resistance, good chemical resistance etc. It is used in shipbuilding, textile industries and also in biomedical applications. UHMWPE is processed by powder processing technique because of its high melt viscosity at the processing temperature. Powder processing technique involves compaction of polymeric powder under pressure and sintering of the preforms at temperature above its melting point. In this study, we report our results on compaction and sintering behaviour of two grades of UHMWPE with reference to the powder morphology, sintering temperatures and strength development.

  12. Greener routes for recycling of polyethylene terephthalate

    Directory of Open Access Journals (Sweden)

    A.M. Al-Sabagh

    2016-03-01

    Full Text Available The article reviews the different routes for recycling of polyethylene terephthalate. Chemical recycling processes are divided into six groups: methanolysis, glycolysis, hydrolysis, ammonolysis, aminolysis, and other methods. In a large collection of researches for the chemical recycling of PET, the primary objective is to increase the monomer yield while reducing the reaction time and/or carrying out the reaction under mild conditions. This article also presents the impact of the new recyclable catalysts such as ionic liquids on the future developments in the chemical recycling of PET.

  13. Ageing of cable insulators made of polyethylene in nuclear environment; Vieillissement d'isolants de cables en polyethylene en ambiance nucleaire

    Energy Technology Data Exchange (ETDEWEB)

    Khelidj, N

    2006-10-15

    This thesis deals with lifetime prediction for polyethylene in nuclear environment. It is mainly characterised by the search for a non empirical solution. We have tried to elaborate a model describing the polymer evolution (including the skin-core heterogeneity due to the kinetic control of oxidation by oxygen diffusion) at any temperature between ambient and the melting point of the polymer, and at any dose rate between 0 and 1 kGy.h-1, with lifetimes extending to several decades of years. The main difficulty was to take into account the dual character of initiation which results from the combination of polymer radiolysis and hydroperoxide thermal decomposition. The problem was resolved considering first the asymptotic regimes where one initiation process can be neglected relatively to the other one. The kinetic parameters specific to those regimes being identified, we have built a numerical model including all the processes. In the case of un-stabilised polyethylene, this model displays excellent predictive qualities, as well in lifetime, as in thickness distribution of oxidation products. The study of stabilised polyethylenes was then initiated with samples respectively stabilised by a hindered phenol, and a thio-diester. In the case of phenol, the study of consumption kinetics reveals the existence of complex mechanisms, especially the existence of a 'reservoir effect' linked to the presence of a separated phase of phenol in excess. A kinetic model has been proposed, but we still do not know how the results can be generalised to other phenolic stabilizers. (author)

  14. Degradation of Green Polyethylene by Pleurotus ostreatus.

    Directory of Open Access Journals (Sweden)

    José Maria Rodrigues da Luz

    Full Text Available We studied the biodegradation of green polyethylene (GP by Pleurotus ostreatus. The GP was developed from renewable raw materials to help to reduce the emissions of greenhouse gases. However, little information regarding the biodegradation of GP discarded in the environment is available. P. ostreatus is a lignocellulolytic fungus that has been used in bioremediation processes for agroindustrial residues, pollutants, and recalcitrant compounds. Recently, we showed the potential of this fungus to degrade oxo-biodegradable polyethylene. GP plastic bags were exposed to sunlight for up to 120 days to induce the initial photodegradation of the polymers. After this period, no cracks, pits, or new functional groups in the structure of GP were observed. Fragments of these bags were used as the substrate for the growth of P. ostreatus. After 30 d of incubation, physical and chemical alterations in the structure of GP were observed. We conclude that the exposure of GP to sunlight and its subsequent incubation in the presence of P. ostreatus can decrease the half-life of GP and facilitate the mineralization of these polymers.

  15. Degradation of Green Polyethylene by Pleurotus ostreatus.

    Science.gov (United States)

    da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Ribeiro, Karla Veloso Gonçalves; Mendes, Igor Rodrigues; Kasuya, Maria Catarina Megumi

    2015-01-01

    We studied the biodegradation of green polyethylene (GP) by Pleurotus ostreatus. The GP was developed from renewable raw materials to help to reduce the emissions of greenhouse gases. However, little information regarding the biodegradation of GP discarded in the environment is available. P. ostreatus is a lignocellulolytic fungus that has been used in bioremediation processes for agroindustrial residues, pollutants, and recalcitrant compounds. Recently, we showed the potential of this fungus to degrade oxo-biodegradable polyethylene. GP plastic bags were exposed to sunlight for up to 120 days to induce the initial photodegradation of the polymers. After this period, no cracks, pits, or new functional groups in the structure of GP were observed. Fragments of these bags were used as the substrate for the growth of P. ostreatus. After 30 d of incubation, physical and chemical alterations in the structure of GP were observed. We conclude that the exposure of GP to sunlight and its subsequent incubation in the presence of P. ostreatus can decrease the half-life of GP and facilitate the mineralization of these polymers.

  16. Recycling of irradiated high-density polyethylene

    Science.gov (United States)

    Navratil, J.; Manas, M.; Mizera, A.; Bednarik, M.; Stanek, M.; Danek, M.

    2015-01-01

    Radiation crosslinking of high-density polyethylene (HDPE) is a well-recognized modification of improving basic material characteristics. This research paper deals with the utilization of electron beam irradiated HDPE (HDPEx) after the end of its lifetime. Powder of recycled HDPEx (irradiation dose 165 kGy) was used as a filler into powder of virgin low-density polyethylene (LDPE) in concentrations ranging from 10% to 60%. The effect of the filler on processability and mechanical behavior of the resulting mixtures was investigated. The results indicate that the processability, as well as mechanical behavior, highly depends on the amount of the filler. Melt flow index dropped from 13.7 to 0.8 g/10 min comparing the lowest and the highest concentration; however, the higher shear rate the lower difference between each concentration. Toughness and hardness, on the other hand, grew with increasing addition of the recycled HDPEx. Elastic modulus increased from 254 to 450 MPa and material hardness increased from 53 to 59 ShD. These results indicate resolving the problem of further recycling of irradiated polymer materials while taking advantage of the improved mechanical properties.

  17. Nanostructurization and thermal properties of polyethylenes' welds

    Science.gov (United States)

    Galchun, Anatoliy; Korab, Nikolay; Kondratenko, Volodymyr; Demchenko, Valeriy; Shadrin, Andriy; Anistratenko, Vitaliy; Iurzhenko, Maksym

    2015-03-01

    As it is known, polyethylene (PE) is one of the common materials in the modern world, and PE products take the major share on industrial and trade markets. For example, various types of technical PE like PE-63, PE-80, and PE-100 have wide industrial applications, i.e., in construction, for pipeline systems etc. A rapid development of plastics industry outstrips detailed investigation of welding processes and welds' formation mechanism, so they remain unexplored. There is still no final answer to the question how weld's microstructure forms. Such conditions limit our way to the understanding of the problem and, respectively, prevent scientific approaches to the welding of more complicated (from chemical point of view) types of polymers than PE. Taking into account state-of-the-art, the article presents results of complex studies of PE weld, its structure, thermophysical and operational characteristics, analysis of these results, and basing on that some hypotheses of welded joint and weld structure formation. It is shown that welding of dissimilar types of polyethylene, like PE-80 and PE-100, leads to the formation of better-ordered crystallites, restructuring the crystalline phase, and amorphous areas with internal stresses in the welding zone.

  18. Degradation of Green Polyethylene by Pleurotus ostreatus

    Science.gov (United States)

    da Luz, José Maria Rodrigues; Paes, Sirlaine Albino; Ribeiro, Karla Veloso Gonçalves; Mendes, Igor Rodrigues; Kasuya, Maria Catarina Megumi

    2015-01-01

    We studied the biodegradation of green polyethylene (GP) by Pleurotus ostreatus. The GP was developed from renewable raw materials to help to reduce the emissions of greenhouse gases. However, little information regarding the biodegradation of GP discarded in the environment is available. P. ostreatus is a lignocellulolytic fungus that has been used in bioremediation processes for agroindustrial residues, pollutants, and recalcitrant compounds. Recently, we showed the potential of this fungus to degrade oxo-biodegradable polyethylene. GP plastic bags were exposed to sunlight for up to 120 days to induce the initial photodegradation of the polymers. After this period, no cracks, pits, or new functional groups in the structure of GP were observed. Fragments of these bags were used as the substrate for the growth of P. ostreatus. After 30 d of incubation, physical and chemical alterations in the structure of GP were observed. We conclude that the exposure of GP to sunlight and its subsequent incubation in the presence of P. ostreatus can decrease the half-life of GP and facilitate the mineralization of these polymers. PMID:26076188

  19. Severe impingement of lumbar disc replacements increases the functional biological activity of polyethylene wear debris.

    Science.gov (United States)

    Baxter, Ryan M; Macdonald, Daniel W; Kurtz, Steven M; Steinbeck, Marla J

    2013-06-05

    Wear, oxidation, and particularly rim impingement damage of ultra-high molecular weight polyethylene total disc replacement components have been observed following surgical revision. However, neither in vitro testing nor retrieval-based evidence has shown the effect(s) of impingement on the characteristics of polyethylene wear debris. Thus, we sought to determine (1) differences in polyethylene particle size, shape, number, or biological activity that correspond to mild or severe rim impingement and (2) in an analysis of all total disc replacements, regardless of impingement classification, whether there are correlations between the extent of regional damage and the characteristics of polyethylene wear debris. The extent of dome and rim damage was characterized for eleven retrieved polyethylene cores obtained at revision surgery after an average duration of implantation of 9.7 years (range, 4.6 to 16.1 years). Polyethylene wear debris was isolated from periprosthetic tissues with use of nitric acid and was imaged with use of environmental scanning electron microscopy. Subsequently, particle size, shape, number, biological activity, and chronic inflammation scores were determined. Grouping of particles by size ranges that represented high biological relevance (<0.1 to 1-μm particles), intermediate biological relevance (1 to 10-μm particles), and low biological relevance (>10-μm particles) revealed an increased volume fraction of particles in the <0.1 to 1-μm and 1 to 10-μm size ranges in the mild-impingement cohort as compared with the severe-impingement cohort. The increased volume fractions resulted in a higher specific biological activity per unit particle volume in the mild-impingement cohort than in the severe-impingement cohort. However, functional biological activity, which is normalized by particle volume (mm3/g of tissue), was significantly higher in the severe-impingement cohort. This increase was due to a larger volume of particles in all three size

  20. Severe Impingement of Lumbar Disc Replacements Increases the Functional Biological Activity of Polyethylene Wear Debris

    Science.gov (United States)

    Baxter, Ryan M.; MacDonald, Daniel W.; Kurtz, Steven M.; Steinbeck, Marla J.

    2013-01-01

    Background: Wear, oxidation, and particularly rim impingement damage of ultra-high molecular weight polyethylene total disc replacement components have been observed following surgical revision. However, neither in vitro testing nor retrieval-based evidence has shown the effect(s) of impingement on the characteristics of polyethylene wear debris. Thus, we sought to determine (1) differences in polyethylene particle size, shape, number, or biological activity that correspond to mild or severe rim impingement and (2) in an analysis of all total disc replacements, regardless of impingement classification, whether there are correlations between the extent of regional damage and the characteristics of polyethylene wear debris. Methods: The extent of dome and rim damage was characterized for eleven retrieved polyethylene cores obtained at revision surgery after an average duration of implantation of 9.7 years (range, 4.6 to 16.1 years). Polyethylene wear debris was isolated from periprosthetic tissues with use of nitric acid and was imaged with use of environmental scanning electron microscopy. Subsequently, particle size, shape, number, biological activity, and chronic inflammation scores were determined. Results: Grouping of particles by size ranges that represented high biological relevance (10-μm particles) revealed an increased volume fraction of particles in the <0.1 to 1-μm and 1 to 10-μm size ranges in the mild-impingement cohort as compared with the severe-impingement cohort. The increased volume fractions resulted in a higher specific biological activity per unit particle volume in the mild-impingement cohort than in the severe-impingement cohort. However, functional biological activity, which is normalized by particle volume (mm3/g of tissue), was significantly higher in the severe-impingement cohort. This increase was due to a larger volume of particles in all three size ranges. In both cohorts, the functional biological activity correlated with the

  1. Polyethylene magnetic nanoparticle: a new magnetic material for biomedical applications

    Science.gov (United States)

    Chatterjee, Jhunu; Haik, Yousef; Chen, Ching-Jen

    2002-05-01

    Polyethylene magnetic nanoparticles were synthesized by nonsolvent and temperature induced crystallization along with ultrasonication. Low molecular weight polyethylene wax and maghemite were used for forming the composite particles. These particles were further coated with avidin. The nanoparticles are characterized using STEM, AFM and SQUID. Nanomagnetic particles were found to have two distinct morphologies and have superparamagnetic properties.

  2. 21 CFR 177.1630 - Polyethylene phthalate polymers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyethylene phthalate polymers. 177.1630 Section... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as... polymers. Polyethylene phthalate polymers identified in this section may be safely used as, or...

  3. 40 CFR 721.6493 - Amidoamine modified polyethylene glycol (generic).

    Science.gov (United States)

    2010-07-01

    ... Specific Chemical Substances § 721.6493 Amidoamine modified polyethylene glycol (generic). (a) Chemical... as an amidoamine modified polyethylene glycol (PMN P-99-0645) is subject to reporting under this... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Amidoamine modified...

  4. Porous polyethylene implants in facial reconstruction: outcome and complications

    NARCIS (Netherlands)

    Ridwan-Pramana, A.; Wolff, J.; Raziei, A.; Ashton-James, C.E.; Forouzanfar, T.

    2015-01-01

    The aim of the present study was to assess the indications, results and complications of patients treated with porous polyethylene (Medpor®) implants in the Department of Oral and Maxillofacial Surgery of VU Medical Centre, Amsterdam over 17 years. A total of 69 high-density porous polyethylene

  5. Micro X-Ray Computed Tomography Mass Loss Assessment of Different UHMWPE: A Hip Joint Simulator Study on Standard vs. Cross-Linked Polyethylene

    Science.gov (United States)

    Zanini, Filippo; Carmignato, Simone

    2017-01-01

    More than 60.000 hip arthroplasty are performed every year in Italy. Although Ultra-High-Molecular-Weight-Polyethylene remains the most used material as acetabular cup, wear of this material induces over time in vivo a foreign-body response and consequently osteolysis, pain, and the need of implant revision. Furthermore, oxidative wear of the polyethylene provoke several and severe failures. To solve these problems, highly cross-linked polyethylene and Vitamin-E-stabilized polyethylene were introduced in the last years. In in vitro experiments, various efforts have been made to compare the wear behavior of standard PE and vitamin-E infused liners. In this study we compared the in vitro wear behavior of two different configurations of cross-linked polyethylene (with and without the add of Vitamin E) vs. the standard polyethylene acetabular cups. The aim of the present study was to validate a micro X-ray computed tomography technique to assess the wear of different commercially available, polyethylene’s acetabular cups after wear simulation; in particular, the gravimetric method was used to provide reference wear values. The agreement between the two methods is documented in this paper. PMID:28107468

  6. Polyethylene glycol: a game-changer laxative for children.

    Science.gov (United States)

    Alper, Arik; Pashankar, Dinesh S

    2013-08-01

    Constipation is a common problem in children worldwide. It can also be a chronic problem persisting for many months to years. Successful treatment of constipation requires long-term use of laxatives. Commonly used laxatives in children include milk of magnesia, lactulose, mineral oil, and polyethylene glycol. Compared with other laxatives, polyethylene glycol (with and without electrolytes) is a relatively new laxative used during the last decade. Recent studies report excellent efficacy and safety of polyethylene glycol for the long-term treatment of constipation in children. Because of excellent patient acceptance, polyethylene glycol has become a preferred choice of laxative for many practitioners. This article reviews the recently published pediatric literature on biochemistry, efficacy, safety, patient acceptance, and pharmacoeconomics of polyethylene glycol.

  7. Preparation and Electrical Property of Polypyrrole-Polyethylene Composite

    Science.gov (United States)

    Yoshino, Katsumi; Yin, Xiao Hong; Morita, Shigenori; Nakanishi, Yutaka; Nakagawa, Shinichi; Yamamoto, Hideo; Watanuki, Toshiro; Isa, Isao

    1993-02-01

    Polypyrrole-polyethylene composites have been prepared by pressing the mixture of polypyrrole coated and non-coated polyethylene spheres. Electrical conductivity is enhanced by more than 16 orders of magnitude and its activation energy decreases remarkably at concentration of polypyrrole coated polyethylene above around 10-20%, which corresponds to effective polypyrrole concentration of 0.1-0.2%. These characteristics can be explained by a percolation model. That is, at this concentration electrodes are bridged by conducting channel of doped polypyrrole. Thermoelectric power increases in proportion to absolute temperature and is independent on concentration of polypyrrole coated polyethylene sphere above 30%, which support the percolation model. The electrical property of this polypyrrole-polyethylene composite is found to be stable up to 160°C. The application of this composite to the semiconducting layer of a cable has been proposed.

  8. Towards aging mechanisms of cross-linked polyethylene (XLPE) cable insulation materials in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shuaishuai; Fifield, Leonard S.; Bowler, Nicola

    2016-12-19

    Cross-linked polyethylene (XLPE) cable insulation material undergoes simultaneous, accelerated thermal and gamma-radiation aging to simulate the long-term aging environment within nuclear power plants (NPPs). A variety of materials characterization tests, including scanning electron microscopy, thermo-gravimetric analysis, differential scanning calorimetry, oxidation induction time, gel-fraction and dielectric properties measurement, are conducted on pristine and differently aged XLPE samples. A preliminary model of one possible aging mechanism of XLPE cable insulation material under gamma radiation at elevated temperature of 115 °C is suggested.

  9. Dielectric relaxation study of gamma irradiated oriented low-density polyethylene

    CERN Document Server

    Suljovrujic, E; Kostoski, D

    2003-01-01

    The influence of drawing, gamma irradiation and accelerated aging on the dielectric relaxation of low-density polyethylene has been studied using dielectric loss tangent measurements in the temperature range from 25 to 325 K and in the frequency range from 10 sup 3 to 10 sup 6 Hz. The intensity, position and activation energy of the gamma- and beta-dielectric relaxations were found to be strongly dependent upon the changes in the microstructure of the amorphous phase induced by uniaxial orientation, oxidation and crosslinking.

  10. Enzyme-Catalyzed Modifications of Polysaccharides and Poly(ethylene glycol

    Directory of Open Access Journals (Sweden)

    H. N. Cheng

    2012-06-01

    Full Text Available Polysaccharides are used extensively in various industrial applications, such as food, adhesives, coatings, construction, paper, pharmaceuticals, and personal care. Many polysaccharide structures need to be modified in order to improve their end-use properties; this is mostly done through chemical reactions. In the past 20 years many enzyme-catalyzed modifications have been developed to supplement chemical derivatization methods. Typical reactions include enzymatic oxidation, ester formation, amidation, glycosylation, and molecular weight reduction. These reactions are reviewed in this paper, with emphasis placed on the work done by the authors. The polymers covered in this review include cellulosic derivatives, starch, guar, pectin, and poly(ethylene glycol.

  11. Separation of polyethylene glycols and maleimide-terminated polyethylene glycols by reversed-phase liquid chromatography under critical conditions.

    Science.gov (United States)

    Wei, Yanzhen; Zhuo, Renxi; Jiang, Xulin

    2016-11-01

    The separation of polyethylene glycols and maleimide-substituted polyethylene glycol derivatives based on the number of maleimide end-groups under critical liquid chromatography conditions has been investigated on a reversed-phase column. The critical solvent compositions for nonfunctional polyethylene glycols and bifunctional maleimide-substituted polyethylene glycols were determined to be identical at about 40% acetonitrile in water on a reversed-phase octadecyl carbon chain-bonded silica column using mixtures of acetonitrile and water of varying composition as the mobile phase at 25°C. The maleimide-functionalized polyethylene glycols were successfully separated according to maleimide functionality (with zero, one, two, or three maleimide end-groups, respectively) under the critical isocratic elution conditions without obvious effect of molar mass. The separation was mainly due to the hydrophobic interaction between the maleimide end-groups and the column packing. Off-line matrix-assisted laser desorption/ionization time of flight mass spectrometry was used to identify the repeating units and, especially, the end-groups of the maleimide-substituted polyethylene glycols. Liquid chromatography analysis at critical conditions could provide useful information to optimize the synthesis of functional polyethylene glycols. To our knowledge, this is the first report of the baseline separation of maleimide-functionalized polyethylene glycols based on the functionality independent of the molar mass without derivatization by isocratic elution.

  12. Five-Year Experience of Vitamin E-Diffused Highly Cross-Linked Polyethylene Wear in Total Hip Arthroplasty Assessed by Radiostereometric Analysis

    DEFF Research Database (Denmark)

    Nebergall, Audrey K; Troelsen, Anders; Rubash, Harry E;

    2016-01-01

    BACKGROUND: Vitamin E-diffused highly cross-linked polyethylene (VEPE) was developed to reduce oxidation without compromising mechanical strength. The purpose of this study was to evaluate VEPE in vivo using radiostereometric analysis (RSA) and patient-reported outcome measures (PROMs). METHODS: ...

  13. Immediate-type hypersensitivity to polyethylene glycols

    DEFF Research Database (Denmark)

    Wenande, E; Garvey, L H

    2016-01-01

    Polyethylene glycols (PEGs) or macrogols are polyether compounds widely used in medical and household products. Although generally considered biologically inert, cases of mild to life-threatening immediate-type PEG hypersensitivity are reported with increasing frequency. Nevertheless, awareness...... of PEG's allergenic potential remains low, due to a general lack of suspicion towards excipients and insufficient product labelling. Information on immediate-type reactions to PEG is limited to anecdotal reports, and the potential for PEG sensitization and cross-sensitization to PEGylated drugs...... to a range of unrelated products in hospital and at home. Increased awareness of PEG prevalence, PEG hypersensitivity, and improved access to PEG allergy testing, should facilitate earlier diagnosis and reduce the risk of inadvertent re-exposure. This first comprehensive review provides practical information...

  14. Depolymerization of polyethylene terephthalate in supercritical methanol

    Science.gov (United States)

    Goto, Motonobu; Koyamoto, Hiroshi; Kodama, Akio; Hirose, Tsutomu; Nagaoka, Shoji

    2002-11-01

    The degradation of polyethylene terephthalate (PET) in supercritical methanol was investigated with the aim of developing a process for chemical recycling of waste plastics. A batch reactor was used at temperatures of 573-623 K under an estimated pressure of 20 MPa for a reaction time of 2-120 min. PET was decomposed to its monomers, dimethyl terephthalate and ethylene glycol, by methanolysis in supercritical methanol. The reaction products were analysed using size-exclusion chromatography, gas chromatography-mass spectrometry, and reversed-phase liquid chromatography. The molecular weight distribution of the products was obtained as a function of reaction time. The yields of monomer components of the decomposition products including by-products were measured. Continuous kinetics analysis was performed on the experimental data.

  15. Polyethylene glycol-grafted polystyrene particles.

    Science.gov (United States)

    Meng, Fenghua; Engbers, Gerard H M; Feijen, Jan

    2004-07-01

    Densely pegylated particles that can serve as a model system for artificial cells were prepared by covalently grafting amino polyethylene glycol (PEG, molecular weight 3400 or 5000) onto carboxyl polystyrene particles (PS-COOH) using carbodiimide chemistry. PEG-modified particles (PS-PEG) were characterized by determination of the PEG surface concentration, zeta-potential, size, and morphology. Under optimized grafting conditions, a dense "brush-like" PEG layer was formed. A PEG surface concentration of approximately 60 pmol/cm2, corresponding with an average distance between grafted PEG chains of approximately 17 A can be realized. It was shown that grafting of PEG onto PS-COOH reduced the adsorption of proteins from human plasma (85 vol %) in phosphate-buffered saline up to 90%.

  16. Role of polyethylene glycol in childhood constipation.

    Science.gov (United States)

    Phatak, Uma Padhye; Pashankar, Dinesh S

    2014-09-01

    Constipation is a common and chronic problem in children worldwide. Long-term use of laxatives is necessary for successful treatment of chronic constipation. Commonly used laxatives in children include milk of magnesia, lactulose, mineral oil, and polyethylene glycol (PEG). Recent studies report the efficacy and safety of PEG for the long-term treatment of constipation in children. Because of its excellent patient acceptance, PEG is being used widely in children for constipation. In this commentary, we review the recently published pediatric literature on the efficacy, safety, and patient acceptance of PEG. We also assess the role of PEG in childhood constipation by comparing it with other laxatives in terms of efficacy, safety, patient acceptance, and cost.

  17. Renewable polyethylene mimics derived from castor oil.

    Science.gov (United States)

    Türünç, Oĝuz; Montero de Espinosa, Lucas; Meier, Michael A R

    2011-09-01

    An increasing number of reports on the syntheses of carbohydrate- and plant oil-based polymers has been published in ongoing efforts to produce plastic materials from renewable resources. Although many of these polymers are biodegradable and this is a desirable property for certain applications, in some cases non-degradable polymers are needed for long-term use purposes. Polyolefins are one of the most important classes of materials that have already taken their places in our daily life. On the other hand, their production relies on fossil resources. Therefore, within this contribution, we discuss synthetic routes toward a number of polyethylene mimics derived from fatty acids via thiol-ene and ADMET polymerization reactions in order to establish more sustainable routes toward this important class of polymers. Two different diene monomers were thus prepared from castor oil derived platform chemicals, their polymerization via the two mentioned routes was optimized and compared to each other, and their thermal properties were investigated.

  18. Luminescence in crosslinked polyethylene at elevated temperatures

    Science.gov (United States)

    Bamji, S. S.; Bulinski, A. T.; Suzuki, H.; Matsuki, M.; Iwata, Z.

    1993-10-01

    Electrical treeing is often responsible for the breakdown of insulating materials used in power apparatus such as high-voltage transformers, cables, and capacitors. Insulation, such as crosslinked polyethylene (XLPE), used in underground high-voltage cables usually operates at temperatures above ambient. This paper describes the characteristics of luminescence, emitted prior to electrical tree inception, at a crosslinked polyethylene-semiconducting material (XLPE-semicon) interface held above room temperature. Use of a sensitive light detection system showed that XLPE subjected to elevated temperatures emits luminescence even without voltage application. This light was attributed to thermoluminescence which decreased with the decrease in the concentration of the crosslinking by-products present in the polymer. The spectra of thermoluminescence were only in the visible range. On the other hand, electroluminescence occurred when the XLPE-semicon interface was held above room temperature and subjected to high electric stress. This light did not depend on the concentration of the crosslinking by-products and the spectra of electroluminescence were in the visible and the ultraviolet ranges. It is proposed that XLPE-semicon interface held at elevated temperature and subjected to long-term voltage application initially emits both thermoluminescence and electroluminescence. As the crosslinking by-products exude out of the polymer, thermoluminescence decreases with time and ultimately ceases, but electroluminescence occurs as long as the voltage is applied to the polymer. Although the intensity of electroluminescence emitted at high temperature was lower than that emitted at ambient, sufficient ultraviolet radiation was emitted. The ultraviolet radiation could photodegrade the polymer and lead to electrical tree inception.

  19. Quantification of branching in model three-arm star polyethylene

    KAUST Repository

    Ramachandran, Ramnath

    2012-01-24

    The versatility of a novel scaling approach in quantifying the structure of model well-defined 3-arm star polyethylene molecules is presented. Many commercial polyethylenes have long side branches, and the nature and quantity of these branches varies widely among the various forms. For instance, low-density polyethylene (LDPE) is typically a highly branched structure with broad distributions in branch content, branch lengths and branch generation (in hyperbranched structures). This makes it difficult to accurately quantify the structure and the inherent structure-property relationships. To overcome this drawback, model well-defined hydrogenated polybutadiene (HPB) structures have been synthesized via anionic polymerization and hydrogenation to serve as model analogues to long-chain branched polyethylene. In this article, model 3-arm star polyethylene molecules are quantified using the scaling approach. Along with the long-chain branch content in polyethylene, the approach also provides unique measurements of long-chain branch length and hyperbranch content. Such detailed description facilitates better understanding of the effect of branching on the physical properties of polyethylene. © 2012 American Chemical Society.

  20. The Application of Lights-Conversed Polyethylene Film for Agriculture

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Lanthanum-rhodamine (6G and B) complexes were synthesized by Rheological Phase Reaction Method. Lanthanum-rhodamine (6G and B) complexes doped polyethylene films which have a function of lights-conversion were prepared. The emission and excitation spectra were measured. The experiments of growing seedling and culture were carried out in the shed built with doped and undoped polyethylene films. Lanthanum-rhodamine doped polyethylene films which have a function of lights-conversion can efficiently convert the green light in the sunlight to the red light for photosynthesis of crops, to promote the maturing of crops and raise the yield of crops.

  1. Monoblock versus modular polyethylene insert in uncemented total knee arthroplasty

    DEFF Research Database (Denmark)

    Andersen, Mikkel Rathsach; Winther, Nikolaj; Lind, Thomas;

    2016-01-01

    Background and purpose - Backside wear of the polyethylene insert in total knee arthroplasty (TKA) can produce clinically significant levels of polyethylene debris, which can lead to loosening of the tibial component. Loosening due to polyethylene debris could theoretically be reduced in tibial...... as maximum total point motion (MTPM)) of the 2 different implant designs. Results - We did not find any statistically significant difference in MTPM between the groups at 3 months (p = 0.2) or at 6 months (p = 0.1), but at 12 and 24 months of follow-up there was a significant difference in MTPM of 0.36 mm (p...

  2. Reinforcement of the Gas Barrier Properties of Polyethylene and Polyamide Through the Nanocomposite Approach: Key Factors and Limitations

    Directory of Open Access Journals (Sweden)

    Picard E.

    2015-02-01

    Full Text Available In this study, polyamide 6 (PA6 and polyethylene (PE nanocomposites were prepared from melt blending and a detailed characterization of the nanocomposite morphology and gas barrier properties was performed. The choice of the organoclay was adapted to each polymer matrix. Exfoliated morphology and improved gas transport properties were obtained by melt mixing the polar PA6 matrix and the organoclay, whereas a microcomposite with poor barrier properties was formed from the binary PE/organomodified clay mixture. Different modified polyethylenes were examined as compatibilizers for the polyethylene/organoclay system. The effect of compatibilizer molar mass, polarity and content was investigated on the clay dispersion and on the gas barrier properties. The optimal compatibilizer to clay weight ratio was found to be equal to 4 whatever the compatibilizer. However, a high degree of clay delamination was obtained with the high molar mass compatibilizer whereas highly swollen clay aggregates resulted from the incorporation of the low molar mass interfacial agents. Contrary to the PA based system, the barrier properties of PE nanocomposites were not directly related to the clay dispersion state but resulted also from the matrix/clay interfacial interactions. Oxidized wax was identified as a very promising interfacial agent and a step by step study was performed to optimize the gas transport properties of the systems based on PE, oxidized wax and organoclay. In particular, an interesting combination of oxidized wax and high molar mass maleic anhydride grafted polyethylene allowing dividing the gas permeability by a factor 2 in comparison with neat PE was proposed.

  3. Biodegradation of low-density polyethylene (LDPE by mixed culture of Lysinibacillus xylanilyticus and Aspergillus niger in soil.

    Directory of Open Access Journals (Sweden)

    Atefeh Esmaeili

    Full Text Available In this study, two strains of Aspergillus sp. and Lysinibacillus sp. with remarkable abilities to degrade low-density polyethylene (LDPE were isolated from landfill soils in Tehran using enrichment culture and screening procedures. The biodegradation process was performed for 126 days in soil using UV- and non-UV-irradiated pure LDPE films without pro-oxidant additives in the presence and absence of mixed cultures of selected microorganisms. The process was monitored by measuring the microbial population, the biomass carbon, pH and respiration in the soil, and the mechanical properties of the films. The carbon dioxide measurements in the soil showed that the biodegradation in the un-inoculated treatments were slow and were about 7.6% and 8.6% of the mineralisation measured for the non-UV-irradiated and UV-irradiated LDPE, respectively, after 126 days. In contrast, in the presence of the selected microorganisms, biodegradation was much more efficient and the percentages of biodegradation were 29.5% and 15.8% for the UV-irradiated and non-UV-irradiated films, respectively. The percentage decrease in the carbonyl index was higher for the UV-irradiated LDPE when the biodegradation was performed in soil inoculated with the selected microorganisms. The percentage elongation of the films decreased during the biodegradation process. The Fourier transform infra-red (FT-IR, x-ray diffraction (XRD and scanning electron microscopy (SEM were used to determine structural, morphological and surface changes on polyethylene. These analyses showed that the selected microorganisms could modify and colonise both types of polyethylene. This study also confirmed the ability of these isolates to utilise virgin polyethylene without pro-oxidant additives and oxidation pretreatment, as the carbon source.

  4. Biodegradation of low-density polyethylene (LDPE) by mixed culture of Lysinibacillus xylanilyticus and Aspergillus niger in soil.

    Science.gov (United States)

    Esmaeili, Atefeh; Pourbabaee, Ahmad Ali; Alikhani, Hossein Ali; Shabani, Farzin; Esmaeili, Ensieh

    2013-01-01

    In this study, two strains of Aspergillus sp. and Lysinibacillus sp. with remarkable abilities to degrade low-density polyethylene (LDPE) were isolated from landfill soils in Tehran using enrichment culture and screening procedures. The biodegradation process was performed for 126 days in soil using UV- and non-UV-irradiated pure LDPE films without pro-oxidant additives in the presence and absence of mixed cultures of selected microorganisms. The process was monitored by measuring the microbial population, the biomass carbon, pH and respiration in the soil, and the mechanical properties of the films. The carbon dioxide measurements in the soil showed that the biodegradation in the un-inoculated treatments were slow and were about 7.6% and 8.6% of the mineralisation measured for the non-UV-irradiated and UV-irradiated LDPE, respectively, after 126 days. In contrast, in the presence of the selected microorganisms, biodegradation was much more efficient and the percentages of biodegradation were 29.5% and 15.8% for the UV-irradiated and non-UV-irradiated films, respectively. The percentage decrease in the carbonyl index was higher for the UV-irradiated LDPE when the biodegradation was performed in soil inoculated with the selected microorganisms. The percentage elongation of the films decreased during the biodegradation process. The Fourier transform infra-red (FT-IR), x-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine structural, morphological and surface changes on polyethylene. These analyses showed that the selected microorganisms could modify and colonise both types of polyethylene. This study also confirmed the ability of these isolates to utilise virgin polyethylene without pro-oxidant additives and oxidation pretreatment, as the carbon source.

  5. Tribological characteristics of polyethylene glycol (PEG) as a lubricant for wear resistance of ultra-high-molecular-weight polyethylene (UHMWPE ) in artificial knee join.

    Science.gov (United States)

    Kobayashi, Masanori; Koide, Takayuki; Hyon, Suong-Hyu

    2014-10-01

    For the longevity of total knee joint prostheses, we have developed an artificial lubricant using polyethylene glycol (PEG) for the prevention of wear of ultra-high-molecular-weight polyethylene (UHMWPE). In the present study, the lubricative function of this PEG lubricant was evaluated by a wear test using Co-Cr alloy and UHMWPE counter surface samples. As a result, human synovial fluid including the PEG lubricant showed good result regarding the wear volume and a worn surface of UHMWPE. Considering its lubrication mechanism, it is suspected that interaction between the PEG molecules and the proteins in synovial fluid was involved. Since PE molecules are also organic compounds having a hydroxyl group at one or both ends, the albumin and PEG molecule complex would have bound more strongly to the metal oxide surface and UHMWPE surfaces might enhance and stabilize the lubricating film between the contact surfaces under the boundary lubrication. This study suggests that PEG lubricant as an intra-articular viscous supplement has the potential to prevent wear of UHMWPE by mixing with synovial fluid and to contribute to the longevity of knee joint prostheses.

  6. 40 CFR 721.7255 - Polyethyleneamine crosslinked with substituted polyethylene glycol (generic).

    Science.gov (United States)

    2010-07-01

    ... substituted polyethylene glycol (generic). 721.7255 Section 721.7255 Protection of Environment ENVIRONMENTAL... substituted polyethylene glycol (generic). (a) Chemical substance and significant new uses subject to... substituted polyethylene glycol with substituted polyethylene glycol (PMN P-01-833) is subject to...

  7. Microstructure and Mechanical Properties of the Butt Joint in High Density Polyethylene Pipe

    Directory of Open Access Journals (Sweden)

    Pashupati Pokharel

    2016-01-01

    Full Text Available The microstructure and mechanical properties of the butt joint in high density polyethylene (HDPE pipes were evaluated by preparing the joints with increasing the cooling time from 10 s to 70 s before pressure created for fusion of the pipes. Here, cold fusion flaws in HDPE butt joint were created with increasing the cooling time around 70 s caused by the close molecular contact followed by insufficient interdiffusion of chain segments back and forth across the wetted interface. The tensile failure mechanism of the welded pipes at different fusion time was projected based on the tensile test of dog-bone shaped, fully notched bar type as well as round U-notched specimens. The mechanical properties of the joints at different fusion time were correlated with the corresponding fracture surface morphology. The weld seam as well as tensile fracture surfaces were etched using strong oxidizing agents. The crystallinity of surface etched weld zone by potassium permanganate based etchant was found higher than unetched sample due to the higher susceptibility of amorphous phase of polyethylene with oxidizing agent. The U-notched tensile test of butt welded HDPE pipe and surface etching of the weldments provided clear delineation about the joint quality.

  8. Effect of polyethylene glycol on electrochemically deposited trivalent chromium layers

    Institute of Scientific and Technical Information of China (English)

    Joo-Yul LEE; Man KIM; Sik-Chol KWON

    2009-01-01

    The structural characteristics of the trivalent chromium deposits and their interfacial behavior in the plating solution with and without polyethylene glycol molecules were observed by using various electrochemical methods such as cyclic voltammetry, open circuit potential transition, electrochemical impedance spectroscopy, scanning electron microscopy and X-ray photoelectron spectrometry. It is shown that the polyethylene glycol molecules make the reductive current density lower in the trivalent chromium plating system and promote a hydrogen evolution reaction through their adsorption on the electrode surface. And the trivalent chromium layer formed from the polyethylene glycol-containing solution has somewhat higher density of cracks on its surface and results in a lower film resistance, lower polarization resistance, and higher capacitance in a corrosive atmosphere. It is also revealed that the formation of chromium carbide layer is facilitated in the presence of polyethylene glycol, which means easier electrochemical codeposition of chromium and carbon, not single chromium deposition.

  9. The Interlayer Stress Analysis of Polyethylene-steel Composite Pipes

    Institute of Scientific and Technical Information of China (English)

    WEI Xu-guang

    2016-01-01

    Polyethylene-steel Composite Pipes is widely used in conveying corrosive media occasions, but the pipe may lose effectiveness in the process of transporting hot and cold media, so the research of stress distribution and variation in polyethylene-steel composite pipes is very necessary.This article first assume that a thin adhesive layer is in between the polyethylene and steel, the adhesive layer along the axial shear stress is the major cause of the polyethylene layer and the steel pipe off sticky.Secondly, we use a method of finite element to computer simulation by ANSYS, and verify initial assumptions. Finally, based on simulation data, we analyse the adhesive layer stress distribution and the variation with different parameters to change.Through the above research, preliminarily summarize the variation and distribution of interlaminar stress, and provide technical support for future design and process improvement of polyethylenesteel pipe.

  10. Histopathology of biocompatible hydroxylapatite-polyethylene composite in ossiculoplasty

    NARCIS (Netherlands)

    Meijer, AGW; Segenhout, HM; Albers, FWJ; van de Want, HJL

    2002-01-01

    The biocompatibility of hydroxylapatite-polyethylene composite implants (HAPEX, Smith and Nephew) was investigated in this study. Eleven middle ear prostheses, removed during revision surgery, have been examined by light microscopy, transmission electron microscopy and scanning electron microscopy.

  11. Mechanical Performance of Rotomoulded Wollastonite-Reinforced Polyethylene Composites

    Science.gov (United States)

    Yuan, Xiaowen; Easteal, Allan J.; Bhattacharyya, Debes

    This paper describes the development of a new processing technology for rotational moulding of wollastonite microfibre (WE) reinforced polyethylene (PE). Manufacturing wollastonite-polyethylene composites involved blending, compounding by extrusion, and granulating prior to rotational moulding. The properties of the resulting composites were characterised by tensile and impact strength measurements. The results show that tensile strength increases monotonically with the addition of wollastonite fibres, but impact strength is decreased. In addition, the processability is also decreased after adding more than 12 vol% WE because of increased viscosity. The effects of a coupling agent, maleated polyethylene (MAPE), on the mechanical performance and processability were also investigated. SEM analysis reveals good adhesion between the fibre reinforcements and polyethylene matrix at the fracture surface with the addition of MAPE. It is proposed that fillers with small particles with high aspect ratio (such as wollastonite) provide a large interfacial area between the filler and the polymer matrix, and may influence the mobility of the molecular chains.

  12. Effect of drought stress induced by polyethylene glycol (PEG) on ...

    African Journals Online (AJOL)

    Effect of drought stress induced by polyethylene glycol (PEG) on germination indices in corn ( Zea mays L.) hybrids. ... African Journal of Biotechnology ... and success in this stage is dependent on moisture content of soil at time of planting.

  13. Tensile mechanical response of polyethylene – clay nanocomposites.

    Directory of Open Access Journals (Sweden)

    2007-03-01

    Full Text Available In this work we report on the microstructural and the mechanical characteristics of high density polyethylene (HDPE-clay nanocomposites, with particular attention to the creep behaviour. The samples were prepared through melt compounding, using two high-density polyethylenes with different melt flow rate (MFR, two different organo-modified clays, and changing the relative amount of a polyethylene grafted with maleic anhydride (PEgMA compatibilizer. The intercalation process is more effective as the matrix melt viscosity decreases (higher MFR, while the clay interlamellar spacing increases as the compatibilizer amount increases. The relative stiffness of the nanocomposites increases with the addition of clay, with a limited enhancement of the relative yield stress. The better intercalation obtained by the addition of the compatibilizer is not accompanied by a concurrent improvement of the tensile mechanical properties. The creep resistance is enhanced by the introduction of clay, with an appreciable dependence on both the polyethylene and the clay type.

  14. Changes in mechanical properties due to gamma irradiation of high-density polyethylene (HDPE

    Directory of Open Access Journals (Sweden)

    S. S. Cota

    2007-06-01

    Full Text Available This paper presents an experimental analysis of the effect of dose and dose rate parameters during gamma irradiation of high-density polyethylene (HDPE samples. Considerations concerning the influence of these parameters on HDPE mechanical strength properties as a result of the predominance of oxidative degradation or of cross-linking are presented. The experimental results show an improvement of HDPE mechanical strength as dose increases, indicating the predominance of cross-linking over oxidative degradation and that lower doses are necessary to obtain a similar change in resistance parameters when radiation is applied at lower dose rates, showing that gamma radiation affects the HDPE in a more efficient way at lower dose rates.

  15. Changes in mechanical properties due to gamma irradiation of high-density polyethylene (HDPE)

    Energy Technology Data Exchange (ETDEWEB)

    Cota, S.S.; Vasconcelos, V.; Senne Junior, M.; Carvalho, L.L.; Rezende, D.B.; Correa, R.F. [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)]. E-mail: sdsc@cdtn.br

    2007-04-15

    This paper presents an experimental analysis of the effect of dose and dose rate parameters during gamma irradiation of high-density polyethylene (HDPE) samples. Considerations concerning the influence of these parameters on HDPE mechanical strength properties as a result of the predominance of oxidative degradation or of cross-linking are presented. The experimental results show an improvement of HDPE mechanical strength as dose increases, indicating the predominance of cross-linking over oxidative degradation and that lower doses are necessary to obtain a similar change in resistance parameters when radiation is applied at lower dose rates, showing that gamma radiation affects the HDPE in a more efficient way at lower dose rates. (author)

  16. Enhanced photocatalytic activity of TiO2 films by modification with polyethylene glycol

    Directory of Open Access Journals (Sweden)

    Álvaro A. Ramírez-Santos

    2012-01-01

    Full Text Available Titanium dioxide porous thin films on the Anatase phase were deposited onto glass slides by the sol-gel method assisted with polyethylene glycol (PEG. The dip-coated films were characterized using scanning electron microscopy (SEM, thermogravimetric analysis (TGA and DTG, UV-visible spectroscopy and X-ray diffraction (XRD. The photocatalytic activity of the films was determined by means of methyl-orange oxidation tests. The resultant PEG-modified films were crack-free and developed a porous structure after calcination at 500 °C. Photo-oxidation tests showed the dependency of catalytic activity of the films on the number of layers (thickness and porosity, i.e. of the interfacial area.

  17. Effect of calcium-ozone treatment on chemical and biological properties of polyethylene terephthalate.

    Science.gov (United States)

    Rashid, Ahmed Nafis; Tsuru, Kanji; Ishikawa, Kunio

    2015-05-01

    Ozone (O3 ) treatment of polyethylene terephthalate (PET) in distilled water was performed in the presence and absence of calcium (Ca(2+) ). PET was oxidized and thus carboxylic and hydroxyl functional groups were introduced on its surface after O3 treatment, regardless of the presence or absence of Ca(2+) . In the case of O3 treatment with Ca(2+) , PET surface was modified with Ca(2+) . Ca(2+) immobilization was confirmed by X-ray photoelectron spectrometric analysis. Hydrophilicity was investigated by measuring contact angles (CA). CA of PET decreased significantly after ozonation. Surface topography of PET before and after ozone treatment was observed by scanning electron microscopy, and showed no morphological changes. In vitro studies showed enhanced rat bone marrow cell responses on the O3 -treated PET surface. Ca(2+) -O3 oxidation at 37°C for 6 h is expected to be an effective method to fabricate PET with good biocompatibility.

  18. Effect of degrading yellow oxo-biodegradable low-density polyethylene films to water quality

    Science.gov (United States)

    Requejo, B. A.; Pajarito, B. B.

    2017-05-01

    Polyethylene (PE) contributes largely to plastic wastes that are disposed in aquatic environment as a consequence of its widespread use. In this study, yellow oxo-biodegradable low-density PE films were immersed in deionized water at 50°C for 49 days. Indicators of water quality: pH, oxidation-reduction potential, turbidity, and total dissolved solids (TDS), were monitored at regular intervals. It was observed that pH initially rises and then slowly decreases with time, oxidation-reduction potential decreases then slowly increases with time, turbidity rises above the control at varied rates, and TDS increases abruptly and rises at a hindered rate. Moreover, the films potentially leach out lead chromate. The results imply that degrading oxo-biodegradable LDPE films results to significant reduction of water quality.

  19. Primary radiation defect production in polyethylene and cellulose.

    Science.gov (United States)

    Polvi, Jussi; Luukkonen, Petri; Nordlund, Kai; Järvi, Tommi T; Kemper, Travis W; Sinnott, Susan B

    2012-11-29

    Irradiation effects in polyethylene and cellulose were examined using molecular dynamics simulations. The governing reactions in both materials were chain scissioning and generation of small hydrocarbon and peroxy radicals. Recombination of chain fragments and cross-linking between polymer chains were found to occur less frequently. Crystalline cellulose was found to be more resistant to radiation damage than crystalline polyethylene. Statistics on radical formation are presented and the dynamics of the formation of radiation damage discussed.

  20. Polymerization of Pyrrole and Thiophene on Polyethylene Adipate Electrodes

    OpenAIRE

    Erturan, Seyfettin; TORAMAN, Burcu YALVAÇ and Sena

    1998-01-01

    Polymerizations of pyrrole and thiophene on a platinum foil coated by polyethylene adipate (PEA) were carried out in acetonitrile by electrochemical methods. Different compositions of semi-conducting composite films of PEA/Polypyrrole(PPy), PEA/Polythiophene(PT) were prepared by the electrochemical polymerization of pyrrole and thiophene on PEA electrode. The polymerization was possible only for a certain thickness of the polyethylene adipate(PEA) on the platinum. Conductivities of PEA/PPy, P...

  1. The mechanical properties of density graded hemp/polyethylene composites

    Science.gov (United States)

    Dauvegis, Raphaël; Rodrigue, Denis

    2015-05-01

    In this work, the production and mechanical characterization of density graded biocomposites based on high density polyethylene and hemp fibres was performed. The effect of coupling agent addition (maleated polyethylene) and hemp content (0-30%) was studied to determine the effect of hemp distribution (graded content) inside the composite (uniform, linear, V and Λ). Tensile and flexural properties are reported to compare the structures, especially in terms of their stress-strain behaviors under tensile loading.

  2. Diamagnetism and Strucure of Nitric Acid-Treated Bulk Polyethylene

    OpenAIRE

    Ania, F.; Baltá Calleja, F. J.; Cagiao, M.E.

    1982-01-01

    An alternative procedure to examine the nature of the end product of nitric-acid-treated bulk polyethylene involving the measurement of the diamagnetic susceptibility is reported. This simple non-destructive method complements previous results obtained by means of IR spectroscopy. Thus after selectively removing the surface layer of the polyethylene lamellae with nitric acid (t > 50h) the diamagnetic susceptibility substantially decreases to values wich are consistent with tilted paraff...

  3. Polyethylene terephthalate degradation under reactor neutron irradiation

    Science.gov (United States)

    Chikaoui, K.; Izerrouken, M.; Djebara, M.; Abdesselam, M.

    2017-01-01

    This paper is devoted to study the defects generated by reactor neutron in polyethylene terephthalate (PET) films. The explored fast neutron fluence ranges from 2.02×1016 to 2.07×1018 n cm-2. The induced damages were investigated using ultraviolet-visible spectrophotometry (UV-vis), Fourier Transform Infrared spectrometry (FTIR) and X-ray diffraction (XRD). The UV-vis spectra show important changes indicating the degradation of the chemical structure and the creation of new chromophores. FTIR spectra reveal that the intensities of the different absorption bands decrease linearly under fast neutron irradiation. The internal reference band at 1410 cm-1 is used to follow the overall damage during irradiation. The 1342 cm-1 band corresponding to CH2 wagging of trans conformation of crystalline phase show a sharpe linear decrease as the fast neutrons fluence goes up. The creation of the monosubstituted benzene, investigated using the 1610 cm-1 band. It shows a linear increase with fast neutron fluence. It is found from XRD analysis that the diffraction peak (100) intensity is drastically reduced after irradiation at 2.02×1016 n cm-2.

  4. On Crystallization in Polypropylene-Polyethylene Blends

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Blends of polypropylene(PP) and low-density polyethylene (LDPE) have beencrystallized to form open structures(“cluster spherulites”) where the droplets of the minorityPP are bridged by PP lamellae which have grown in the LDPE-rich matrix. These are studiedby permanganic etching followed by electron and optical microscopies. Two similar PP typesare compared, one synthesized with Ziegler-Natta catalyst and one with metallocenecatalyst. The metallocene-catalysed material crystallized much more slowly due to thepresence of regio defects in the chains, even though the overall concentration of tacticitydefects in the Ziegler-Natta material is much higher. A mechanism involving reversal ofhelical direction at the regio defect interfering with the regular chain packing in the crystal issuggested. Growth of “cluster spherulites” is faster in regions where low molecular weightmaterial is concentrated. It is slower where droplets are larger, and this is attributed tocompetition between PP lamellar growth in the matrix and diffusion of PP to alreadycrystallized droplets.

  5. Polarimetric studies of polyethylene terephtalate flexible substrates

    Science.gov (United States)

    Stchakovsky, M.; Garcia-Caurel, E.; Warenghem, M.

    2008-12-01

    Polymer sheets are currently used worldwide in a wide range of applications. The manufacturing process of these sheets involves extruding machines that stretch the material in both lateral and longitudinal directions with respect to the machine direction, thus inducing birefringence. In most cases, the film obtained is optically biaxial. Polarimetric spectroscopy (Ellipsometry and Mueller Matrix) combined with conoscopic observation are the methods of choice to study these properties. In this work we report an analysis of commercially available polyethylene terephtalate (PET) films used as substrate for food packaging as well as for embedded electronic devices such as solar cells or flexible displays. Initial observation of these films through polarizing microscope in conoscopic mode reveals first the trace of optical axis plane with respect to the film surface and second, whether the optical axis is acute or not. This preliminary study allows optimal sample positioning for further polarimetric studies. The measurements and modelling are done in both reflection and transmission mode on several spectroscopic polarimetric setups from UV to NIR. The models give as a main result, the dielectric tensor of the film as well as its orientation with respect to the laboratory reference frame.

  6. Final report on the safety assessment of polyethylene.

    Science.gov (United States)

    2007-01-01

    Polyethylene is an ethylene polymer used for a variety of purposes in cosmetics as an abrasive, adhesive, binder or bulking agent, an emulsion stabilizer, a film former, an oral care agent, and as a nonaqueous viscosity-increasing agent. Polyethylene is also used in food packaging materials and medical products, including prosthetics. The molecular weight of Polyethylene as used in cosmetics varies over a wide range. The lowest reported molecular weight is 198 Daltons and the highest is 150,000. In any given polymer preparation, there can be a broad range of molecular weights. Cellular and tissue responses to Polyethylene, determined as part of implant biocompatibility testing, include fibrous connective tissue build-up around the implant material that varies as a function of the physical form of the implant material. Specific assays for osteoblast proliferation and collagen synthesis demonstrated a reduction as a function of exposure to Polyethylene particles that is inversely related to particle size. The effect of Polyurethane particles on monocyte-derived macrophages, however, had a stimulatory effect, prolonging the survival of these cells in culture. The LD50 for Polyethylene, with an average molecular weight of 450, in rats was > 2000 mg/kg. For Polyethylene with an average molecular weight of 655, the LD50 was > 5.0 g/kg. Toxicity testing in rats shows no adverse effects at Polyethylene (molecular weight not given) doses of 7.95 g/kg or at 1.25%, 2.50%, or 5.00% in feed for 90 days. Dermal irritation studies on rabbits in which 0.5 g of Polyethylene (average molecular weight of 450) was administered in 0.5 ml of water caused no irritation or corrosive effects; Polyethylene with an average molecular weight of 655 was a mild irritant. Polyethylene (average molecular weight of 450) did not cause dermal sensitization in guinea pigs tested with 50% Polyethylene (w/w) in arachis oil BP. Polyethylene, with a molecular weight of 450 and a molecular weight of 655

  7. Curcumin Encapsulated into Methoxy Poly(Ethylene Glycol) Poly(ε-Caprolactone) Nanoparticles Increases Cellular Uptake and Neuroprotective Effect in Glioma Cells.

    Science.gov (United States)

    Marslin, Gregory; Sarmento, Bruno Filipe Carmelino Cardoso; Franklin, Gregory; Martins, José Alberto Ribeiro; Silva, Carlos Jorge Ribeiro; Gomes, Andreia Ferreira Castro; Sárria, Marisa Passos; Coutinho, Olga Maria Fernandes Pereira; Dias, Alberto Carlos Pires

    2017-03-01

    Curcumin is a natural polyphenolic compound isolated from turmeric (Curcuma longa) with well-demonstrated neuroprotective and anticancer activities. Although curcumin is safe even at high doses in humans, it exhibits poor bioavailability, mainly due to poor absorption, fast metabolism, and rapid systemic elimination. To overcome these issues, several approaches, such as nanoparticle-mediated targeted delivery, have been undertaken with different degrees of success. The present study was conducted to compare the neuroprotective effect of curcumin encapsulated in poly(ε-caprolactone) and methoxy poly(ethylene glycol) poly(ε-caprolactone) nanoparticles in U251 glioblastoma cells. Prepared nanoparticles were physically characterized by laser doppler anemometry, transmission electron microscopy, and X-ray diffraction. The results from laser doppler anemometry confirmed that the size of poly(ε-caprolactone) and poly(ethylene glycol) poly(ε-caprolactone) nanoparticles ranged between 200-240 nm for poly(ε-caprolactone) nanoparticles and 30-70 nm for poly(ethylene glycol) poly(ε-caprolactone) nanoparticles, and transmission electron microscopy images revealed their spherical shape. Treatment of U251 glioma cells and zebrafish embryos with poly(ε-caprolactone) and poly(ethylene glycol) poly(ε-caprolactone) nanoparticles loaded with curcumin revealed efficient cellular uptake. The cellular uptake of poly(ethylene glycol) poly(ε-caprolactone) nanoparticles was higher in comparison to poly(ε-caprolactone) nanoparticles. Moreover, poly(ethylene glycol) poly(ε-caprolactone) di-block copolymer-loaded curcumin nanoparticles were able to protect the glioma cells against tBHP induced-oxidative damage better than free curcumin. Together, our results show that curcumin-loaded poly(ethylene glycol) poly(ε-caprolactone) di-block copolymer nanoparticles possess significantly stronger neuroprotective effect in U251 human glioma cells compared to free curcumin and curcumin

  8. Surface modification of poly(ethylene terephthalate) by plasma polymerization of poly(ethylene glycol).

    Science.gov (United States)

    Sakthi Kumar, D; Fujioka, Masayori; Asano, Kentaro; Shoji, Atsumu; Jayakrishnan, Athipettah; Yoshida, Yasuhiko

    2007-09-01

    Poly(ethylene glycol) (PEG) was 'polymerized' onto poly(ethylene terephthalate) (PET) surface by radio frequency (RF) plasma polymerization of PEG (average molecular weight 200 Da) at a monomer vapour partial pressure of 10 Pa. Thin films strongly adherent onto PET could be produced by this method. The modified surface was characterized by infra red (IR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), cross-cut test, contact angle measurements and static platelet adhesion studies. The modified surface, believed to be extensively cross-linked, however showed all the chemical characteristics of PEG. The surface was found to be highly hydrophilic as evidenced by an interfacial free energy of about 0.7 dynes/cm. AFM studies showed that the surface of the modified PET became smooth by the plasma polymerized deposition. Static platelet adhesion studies using platelet rich plasma (PRP) showed considerably reduced adhesion of platelets onto the modified surface by SEM. Plasma 'polymerization' of a polymer such as PEG onto substrates may be a novel and interesting strategy to prepare PEG-like surfaces on a variety of substrates since the technique allows the formation of thin, pin-hole free, strongly adherent films on a variety of substrates.

  9. Structure-property relationship in polyethylene reinforced by polyethylene-grafted multi-walled carbon nanotubes.

    Science.gov (United States)

    Causin, Valerio; Yang, Bing-Xing; Marega, Carla; Goh, Suat Hong; Marigo, Antonio

    2008-04-01

    Polyethylene-grafted multiwalled carbon nanotubes (PE-g-MWNT) were used to reinforce polyethylene (PE). The nanocomposites possessed not only improved stiffness and strength, but also increased ductility and toughness. The effects on the structure and morphology of composites due to pristine multiwalled carbon nanotubes (MWNT) and PE-g-MWNT were studied and compared using small angle X-ray scattering (SAXS), wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). The SAXS long period, crystalline layer thickness and crystallinity of polymer lamellar stacks were found to decrease significantly in MWNT composites, while the decreases were much smaller in PE-g-MWNT composites. PE-g-MWNT allowed a more efficient and unhindered crystallization at a lamellar level, while MWNT disrupted the order of lamellar stacks, probably because of their tendency to aggregate. The SAXS crystallinity and the mechanical properties of the composites showed similar trends as a function of MWNT content. This suggested that the improvement of the interfacial strength between polymer and carbon nanotubes was a result of synergistic effects of better dispersion of the filler, better stress transfer, due to the grafting of polymer and MWNT, and the nucleation of a crystalline phase around MWNT. The latter effect was confirmed by measurements of kinetics of non-isothermal crystallization.

  10. The effect of polyethylene glycol on the characteristics of kenaf cellulose/low-density polyethylene biocomposites.

    Science.gov (United States)

    Tajeddin, Behjat; Rahman, Russly Abdul; Abdulah, Luqman Chuah

    2010-08-01

    Toward the development of biocomposites for packaging applications, the possibility of using kenaf cellulose (KC) was investigated in the production of low-density polyethylene (LDPE)/KC/polyethylene glycol (PEG) biocomposites. First, cellulose was extracted from the cell walls of kenaf-bast fibers. Then, different weights of LDPE, KC, and PEG were blended, and the effects of varying the concentrations of KC and PEG on the synthesis process were evaluated, and the resulting composites were characterized with respect to their mechanical, thermal, biodegradability and water-absorption properties. A scanning electron microscope (SEM) was also used to observe the surface morphology of the samples before and after biodegradation tests. The results showed that the mechanical properties of the biocomposites decreased slightly as the KC content was increased from 0 to 50wt% in the biocomposite formulation; however, there was a good homogeneity between samples with added PEG. The addition of KC improved the thermal resistance of these biocomposites; PEG also had positive role in the thermal behavior of the composites. Based on a soil-burial test, the biodegradability of the composites showed a clear trend of increase degradation with increasing KC content in the formulation. While water-absorption values for the composites were higher than that of pure LDPE polymer, the addition of PEG to the formulation reduced the water absorption of the composites.

  11. Effect of amine functionalized polyethylene on clay-silver dispersion for polyethylene nanocomposites

    Science.gov (United States)

    Sánchez-Valdes, S.; Ibarra-A, M. C.; Ramírez-V, E.; Ramos-V, L. F.; Martinez-C, J. G.; Romero-G, J.; Ledezma-P, A. S.; Rodriguez-F, O. S.

    2014-08-01

    The compatibilization provided by maleic anhydride (MA) and 2-[2-(dimethylamino)-ethoxy] ethanol (DMAE) functionalized polyethylene for forming polyethylene-based nanocomposites was studied and compared. MA was grafted into PE by melt mixing to obtain PEgMA (compatibilizer 1), thereafter, PEgMA was reacted with DMAE and an antioxidant also by melt mixing to obtain PAgDMAE (compatibilizer 2). These compatibilizers were reacted using ultrasound with a solution of AgNO3 0.04 M and Ethylene glycol. Ammonium hydroxide was added in a ratio of 2:1 molar with respect to silver nitrate. These silver coated compatibilizers were mixed with PE and nano-clay (Cloisite I28E), thus forming the different hybrid PE-clay-silver nanocomposites. FTIR confirmed the formation of these two compatibilizers. All the compatibilized nanocomposites had better filler (clay and silver) dispersion and exfoliation compared to the uncompatibilized PE nanocomposites. X-ray diffraction, mechanical and antimicrobial properties attained showed that the PEgDMAE produced the better dispersed PE, clay and silver nanocomposites. The obtained nanocomposites showed outstanding antimicrobial properties against bacteria, Escherichia coli and fungus, Aspergillus niger. It is concluded that the PEgDMAE offers an outstanding capability for preparing nanocomposites with highly exfoliated and dispersed filler into the PE matrix.

  12. Preparation of a novel infrared low-emissive coating from the Cu powder modified by the polyethylene wax

    Science.gov (United States)

    Wu, Guangwen; Yu, Demei

    2012-01-01

    Cu powder was coated with polyethylene wax via the flux-capping method in hope to avoid the oxidation of it, so the increment of the infrared emissivity of the coating can be greatly reduced. The prepared product was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The infrared emissivity of the prepared material was measured by Infrared Emissometer. The influence parameters that will affect the emissivity of the coating were systematically investigated, such as the content of coated Cu powder, coating fineness, coating thickness and aging process. The results indicated that the infrared emissivity value of the coating was reduced after Cu powder was coated with polyethylene wax. The polyethylene wax/Cu composites presented a homogenous sheet structure when the content of Cu powder increased to 30 wt.%, and it has a lower emissivity. The infrared emissivity of the coating increases rapidly as thickness increases and becomes steady above thickness of 70 μm. The composite coating exhibits lower emissivity value and excellent physical properties at coated Cu content of 20 wt.%. The emissivity of the coating that was prepared from the modification of the Cu powder was decreased with the decrement of the grinding fineness and increased with the aging time. The emissivity of the coating that was prepared from the modification of the Cu powder is always lower than that of the coating that only composed of the Cu powder with the increment of the aging time. Therefore, it can be concluded that the anti-oxidation of Cu powder is greatly improved after it was modified by polyethylene wax, which results in a novel coating with long-run low emissivity.

  13. A multicenter approach evaluating the impact of vitamin e-blended polyethylene in cementless total hip replacement.

    Science.gov (United States)

    Jäger, Marcus; van Wasen, Andrea; Warwas, Sebastian; Landgraeber, Stefan; Haversath, Marcel; Group, Vitas

    2014-04-22

    Since polyethylene is one of the most frequently used biomaterials as a liner in total hip arthroplasty, strong efforts have been made to improve design and material properties over the last 50 years. Antioxidants seems to be a promising alternative to further increase durability and reduce polyethylene wear in long term. As of yet, only in vitro results are available. While they are promising, there is yet no clinical evidence that the new material shows these advantages in vivo. To answer the question if vitamin-E enhanced ultra-high molecular weight polyethylene (UHMWPE) is able to improve long-term survivorship of cementless total hip arthroplasty we initiated a randomized long-term multicenter trial. Designed as a superiority study, the oxidation index assessed in retrieval analyses of explanted liners was chosen as primary parameter. Radiographic results (wear rate, osteolysis, radiolucency) and functional outcome (Harris Hip Scores, University of California-Los Angeles, Hip Disability and Osteoarthritis Outcome Score, Visual Analogue Scale) will serve as secondary parameters. Patients with the indication for a cementless total hip arthroplasty will be asked to participate in the study and will be randomized to either receive a standard hip replacement with a highly cross-linked UHMWPE-X liner or a highly cross-linked vitamin-E supplemented UHMWPE-XE liner. The follow-up will be 15 years, with evaluation after 5, 10 and 15 years. The controlled randomized study has been designed to determine if Vitamin-E supplemented highly cross-linked polyethylene liners are superior to standard XLPE liners in cementless total hip arthroplasty. While several studies have been started to evaluate the influence of vitamin-E, most of them evaluate wear rates and functional results. The approach used for this multicenter study, to analyze the oxidation status of retrieved implants, should make it possible to directly evaluate the ageing process and development of the implant

  14. A multicenter approach evaluating the impact of vitamin E-blended polyethylene in cementless total hip replacement

    Directory of Open Access Journals (Sweden)

    Marcus Jäger

    2014-04-01

    Full Text Available Since polyethylene is one of the most frequently used biomaterials as a liner in total hip arthroplasty, strong efforts have been made to improve design and material properties over the last 50 years. Antioxidants seems to be a promising alternative to further increase durability and reduce polyethylene wear in long term. As of yet, only in vitro results are available. While they are promising, there is yet no clinical evidence that the new material shows these advantages in vivo. To answer the question if vitamin-E enhanced ultra-high molecular weight polyethylene (UHMWPE is able to improve long-term survivorship of cementless total hip arthroplasty we initiated a randomized long-term multicenter trial. Designed as a superiority study, the oxidation index assessed in retrieval analyses of explanted liners was chosen as primary parameter. Radiographic results (wear rate, osteolysis, radiolucency and functional outcome (Harris Hip Scores, University of California-Los Angeles, Hip Disability and Osteoarthritis Outcome Score, Visual Analogue Scale will serve as secondary parameters. Patients with the indication for a cementless total hip arthroplasty will be asked to participate in the study and will be randomized to either receive a standard hip replacement with a highly cross-linked UHMWPE-X liner or a highly cross-linked vitamin-E supplemented UHMWPE-XE liner. The follow-up will be 15 years, with evaluation after 5, 10 and 15 years. The controlled randomized study has been designed to determine if Vitamin-E supplemented highly cross-linked polyethylene liners are superior to standard XLPE liners in cementless total hip arthroplasty. While several studies have been started to evaluate the influence of vitamin-E, most of them evaluate wear rates and functional results. The approach used for this multicenter study, to analyze the oxidation status of retrieved implants, should make it possible to directly evaluate the ageing process and development

  15. Degradation behavior of linear low density polyethylene by ultraviolet radiation exposition for agricultural applications

    Energy Technology Data Exchange (ETDEWEB)

    Poveda, Patricia N.S.; Silva, Leonardo G.A., E-mail: lgasilva@ipen.br, E-mail: patricianegrini@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Ciro, Rosemeire, E-mail: rosemeireciro@msn.com [Faculdades Oswaldo Cruz (FOC), Sao Paulo, SP (Brazil); Viana, Hamilton M., E-mail: hmviana@gmail.com [Centro Universitario Fundacao de Santo Andre (FSA/FAENG), Santo Andre, SP (Brazil)

    2013-07-01

    Polyethylene is the most important polymer used in agricultural applications. Polymers are susceptible to changes in their chemical structures that affect their mechanical properties under weather condition. In Polyethylene, photo-oxidation can occur because of impurities or chromophore groups (catalytic residue, mineral fillers, some commercial additives as stabilizers, lubricants, plasticizers, etc.). The critical ageing factors for greenhouse built with LDPE film are: total solar radiation, air temperature, relative humidity, mechanical stress, agrochemicals, air pollution, and combinations of these factors. Exposure of plastics to UV radiation causes a loss in their mechanical properties and/or change in appearance, including reduced ductility, color changes, yellowing and cracking. Additives are added to plastics to enhance the durability of the final product. Today, there are several additive systems (light stabilizers) developed to work according to resin, final application, type of cultivation, and other characteristics. The main types of light stabilizers are: UV absorbers, quenchers and free radicals scavengers. In addition to the conventional organic additives, some inorganic additives were obtained recently with the development of nanotechnology. This study evaluates the different additive systems (HALS, NPCC, nZnO and nTiO{sub 2}), applied 0.25% (in weight) in LLDPE. The samples were mixed by high rotation homogenizer and extrusion. Later, the samples were molded by injection and aged in QUV-B simulating 6 months of exposure to weather. Tests of FT-IR and tensile strength comparing to the non-aged samples were carried out in order to evaluate the performance of several additive systems concerning the degradation behavior of linear low density polyethylene. (author)

  16. ANALYSIS OF BRANCHING DISTRIBUTION IN POLYETHYLENES BY DIFFERENTIAL SCANNING CALORIMETRY

    Institute of Scientific and Technical Information of China (English)

    Robert Shanks; Fei Chen; Gandara Amarasinghe

    2003-01-01

    Short chain branching has been characterized using thermal fractionation, a stepwise isothermal crystallization technique, followed by a melting analysis scan using differential scanning calorimetry. Short chain branching distribution was also characterized by a continuous slow cooling crystallization, followed by a melting analysis scan. Four different polyethylenes were studied: Ziegler-Natta gas phase, Ziegler-Natta solution, metallocene, constrained-geometry single site catalyzed polyethylenes. The branching distribution was calculated from a calibration of branch content with melting temperature. The lamellar thickness was calculated based on the thermodynamic melting temperature of each polyethylene and the surface free energy of the crystal face. The branching distribution and lamellar thickness distribution were used to calculate weight average branch content, mean lamellar thickness, and a branch dispersity index. The results for the branch content were in good agreement with the known comonomer content of the polyethylenes. A limitation was that high branch content polyethylenes did not reach their potential crystallization at ambient temperatures. Cooling to sub-ambient was necessary to equilibrate the crystallization, but melting temperature versus branch content was not applicable after cooling to below ambient because the calibration data were not performed in this way.

  17. ANALYSIS OF BRANCHING DISTRIBUTION IN POLYETHYLENES BY DIFFERENTIAL SCANNING CALORIMETRY

    Institute of Scientific and Technical Information of China (English)

    RobertShanks; FeiChan; GandaraAmarasinghe; RobertShanks

    2003-01-01

    Short chain branching has been characterized using thermal fractionation,a stepwise isothermal crystallization technique,followed by a melting analysis scan using differential scanning calorimetry.Short chain branching distribution was also characterized by a continuous slow cooling crystallization,followed by a melting analysis scan.Four different polyethylenes were studied:Ziegler-Natta gas phase,Ziegler-Natta solution,metallocene,constrained-geometry single site catalyzed polyethylenes.The branching distribution was calculated from a calibration of branch content with melting temperature.The lamellar thickness was calculated based on the thermodynamic melting temperature of each polyethylene and the surface free energy of the crystal face.The branching distribution and lamellar thickness distribution were used to calculate weight average branch content,mean lamellar thickness,and a branch dispersity index.The results for the branch content were in good agreement with the known comonomer content of the polyethylenes.A limitation was that high branch content polyethylenes did not reach their potential crystallization at ambient temperatures.Cooling to sub-ambient was necessary to equilibrate the crystallization,but melting temperature versus branch content was not applicable after cooling to below ambient because the calibration data were not performed in this way.

  18. Polyethylene-waste tire dust composites via in situ polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Reyes A, Y. K.; Narro C, R. I.; Ramos A, M. E. [Universidad Autonoma de Coahuila, Facultad de Ciencias Quimicas, Blvd. Venustiano Carranza s/n, 25280 Saltillo, Coahuila (Mexico); Neira V, M. G.; Diaz E, J.; Enriquez M, F.; Valencia L, L. A.; Saade C, H.; Diaz de L, R., E-mail: ramon.diazdeleon@ciqa.edu.mx [Centro de Investigacion en Quimica Aplicada, Blvd. Enrique Reyna Hermosillo No. 40, Col. San Jose de los Cerritos, 25293 Saltillo, Coahuila (Mexico)

    2014-10-01

    Polyethylene/waste tire dust (WTD) composites were obtained by an in situ polymerization technique. The surface of the WTD was modified with deposition of polyethylene by using plasma polymerization. Ethylene polymerization was carried out using bis(cyclopentadienyl) titanium dichloride (Cp{sub 2}TiCl{sub 2}) as homogeneous metallocenes catalyst, while diethylaluminum chloride (DEAC), ethyl aluminum sesquichloride (EASC) and methyl alumino xane (Mao) were used as co-catalysts at two different [Al]/[Ti] molar ratio. The main characteristics of the obtained polyethylenes were determined by size exclusion chromatography, thermogravimetric analysis, differential scanning calorimetry and wide-angle X-ray diffraction. The results showed that by using EASC and Mao the highest catalytic activities were presented at a [Al]/[Ti] molar ratio of 9.17 and 18.33 respectively. Even though it was possible to obtain polyethylene using WTD (modified or unmodified) the catalytic activity was lower than in the case in which no WTD was added in ethylene polymerization. Scanning transmission electronic microscopy images evidenced that the original morphology of the polyethylenes was not modified by the presence of WTD. (Author)

  19. Pulmonary surfactant adsorption is increased by hyaluronan or polyethylene glycol.

    Science.gov (United States)

    Taeusch, H William; Dybbro, Eric; Lu, Karen W

    2008-04-01

    In acute lung injuries, inactivating agents may interfere with transfer (adsorption) of pulmonary surfactants to the interface between air and the aqueous layer that coats the interior of alveoli. Some ionic and nonionic polymers reduce surfactant inactivation in vitro and in vivo. In this study, we tested directly whether an ionic polymer, hyaluronan, or a nonionic polymer, polyethylene glycol, enhanced adsorption of a surfactant used clinically. We used three different methods of measuring adsorption in vitro: a modified pulsating bubble surfactometer; a King/Clements device; and a spreading trough. In addition we measured the effects of both polymers on surfactant turbidity, using this assay as a nonspecific index of aggregation. We found that both hyaluronan and polyethylene glycol significantly increased the rate and degree of surfactant material adsorbed to the surface in all three assays. Hyaluronan was effective in lower concentrations (20-fold) than polyethylene glycol and, unlike polyethylene glycol, hyaluronan did not increase apparent aggregation of surfactant. Surfactant adsorption in the presence of serum was also enhanced by both polymers regardless of whether hyaluronan or polyethylene glycol was included with serum in the subphase or added to the surfactant applied to the surface. Therefore, endogenous polymers in the alveolar subphase, or exogenous polymers added to surfactant used as therapy, may both be important for reducing inactivation of surfactant that occurs with various lung injuries.

  20. Modeling uptake of hydrophobic organic contaminants into polyethylene passive samplers.

    Science.gov (United States)

    Thompson, Jay M; Hsieh, Ching-Hong; Luthy, Richard G

    2015-02-17

    Single-phase passive samplers are gaining acceptance as a method to measure hydrophobic organic contaminant (HOC) concentration in water. Although the relationship between the HOC concentration in water and passive sampler is linear at equilibrium, mass transfer models are needed for nonequilibrium conditions. We report measurements of organochlorine pesticide diffusion and partition coefficients with respect to polyethylene (PE), and present a Fickian approach to modeling HOC uptake by PE in aqueous systems. The model is an analytic solution to Fick's second law applied through an aqueous diffusive boundary layer and a polyethylene layer. Comparisons of the model with existing methods indicate agreement at appropriate boundary conditions. Laboratory release experiments on the organochlorine pesticides DDT, DDE, DDD, and chlordane in well-mixed slurries support the model's applicability to aqueous systems. In general, the advantage of the model is its application in the cases of well-agitated systems, low values of polyethylene-water partioning coefficients, thick polyethylene relative to the boundary layer thickness, and/or short exposure times. Another significant advantage is the ability to estimate, or at least bound, the needed exposure time to reach a desired CPE without empirical model inputs. A further finding of this work is that polyethylene diffusivity does not vary by transport direction through the sampler thickness.