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Sample records for homopolymer oxirane polymer

  1. 78 FR 70878 - Octadecanoic Acid, 12-Hydroxy-, Homopolymer, Ester With 2-Methyloxirane Polymer With Oxirane...

    Science.gov (United States)

    2013-11-27

    ... AGENCY 40 CFR Part 180 Octadecanoic Acid, 12-Hydroxy-, Homopolymer, Ester With 2- Methyloxirane Polymer... residues of Octadecanoic Acid, 12-Hydroxy-, Homopolymer, Ester with 2-Methyloxirane Polymer with Oxirane... a maximum permissible level for residues of Octadecanoic Acid, 12-Hydroxy-, Homopolymer, Ester...

  2. 75 FR 52269 - Acetic Acid Ethenyl Ester, Polymer With Oxirane; Tolerance Exemption

    Science.gov (United States)

    2010-08-25

    ...-2010-0429; FRL-8841-2] Acetic Acid Ethenyl Ester, Polymer With Oxirane; Tolerance Exemption AGENCY... from the requirement of a tolerance for residues of acetic acid ethenyl ester, polymer with oxirane... permissible level for residues of acetic acid ethenyl ester, polymer with oxirane on food or feed...

  3. 40 CFR 721.6181 - Fatty acid, reaction product with substituted oxirane, formaldehyde-phenol polymer glycidyl ether...

    Science.gov (United States)

    2010-07-01

    ... substituted oxirane, formaldehyde-phenol polymer glycidyl ether, substituted proplyamine and...-phenol polymer glycidyl ether, substituted proplyamine and polyethylenepolyamines (generic). (a) Chemical... as fatty acid, reaction product with substituted oxirane, formaldehyde-phenol polymer glycidyl...

  4. 40 CFR 721.10189 - Fatty acids, tall-oil, reaction products with (butoxymethyl) oxirane formaldehyde-phenol polymer...

    Science.gov (United States)

    2010-07-01

    ... products with (butoxymethyl) oxirane formaldehyde-phenol polymer glycidyl ether, morpholinepropanamine...-phenol polymer glycidyl ether, morpholinepropanamine, propylene glycol diamine and aliphatic polyamine, N... products with (butoxymethyl) oxirane formaldehyde-phenol polymer glycidyl ether,...

  5. 40 CFR 721.5560 - Formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz[c...

    Science.gov (United States)

    2010-07-01

    ... (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz oxaphosphorin-6-oxide. 721.5560 Section 721... Formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with 6H-dibenz oxaphosphorin-6... identified as formaldehyde, polymer with (chloromethyl) oxirane and phenol, reaction products with...

  6. Dye linked conjugated homopolymers: using conjugated polymer electroluminescence to optically pump porphyrin-dye emission

    DEFF Research Database (Denmark)

    Nielsen, K.T.; Spanggaard, H.; Krebs, Frederik C

    2004-01-01

    . Electroluminescent devices of the homopolymer itself and of the zinc-porphyrin containing polymer were prepared and the nature of the electroluminescence was characterized. The homopolymer segments were found to optically pump the emission of the zinc-porphyrin dye moities. The homopolymer exhibits blue......Zinc-porphyrin dye molecules were incorporated into the backbone of a conjugated polymer material by a method, which allowed for the incorporation of only one zinc-porphyrin dye molecule into the backbone of each conjugated polymer molecule. The electronic properties of the homopolymer were......-green emission and the zinc-porphyrin linked homopolymers emit near-infrared/infrared light. This was demonstrated to be due to electroluminescence pumping of the zinc-porphyrin moieties that were covalently linked to homopolymer material. When only one zinc-porphyrin dye was incorporated into the backbone...

  7. 75 FR 4288 - Oxirane, 2-Methyl-, Polymer with Oxirane, Dimethyl Ether; Tolerance Exemption

    Science.gov (United States)

    2010-01-27

    ... natural aquatic environment. 2. The polymer does contain as an integral part of its composition the atomic... composition, except as impurities, any element other than those listed in 40 CFR 723.250(d)(2)(ii). 4. The... recordkeeping requirements. Dated: January 19, 2010. Lois Rossi, Director, Registration Division, Office...

  8. 40 CFR 721.5585 - 4,4′-(1-methylethylidene)bisphenol, polymer with (chloromethyl)oxirane and a diamine (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 4,4â²-(1-methylethylidene)bisphenol...-methylethylidene)bisphenol, polymer with (chloromethyl)oxirane and a diamine (generic). (a) Chemical substance and...-methylethylidene)bisphenol, polymer with (chloromethyl) oxirane and a diamine (PMN P-97-0916) is subject...

  9. Tailoring the physical properties of homopolymers and polymer nanocomposites via solid-state processing

    Science.gov (United States)

    Pierre, Cynthia

    Numerous approaches can be used to modify polymer properties. In this thesis, it is demonstrated that an innovative, continuous, industrially scalable process called solid-state shear pulverization (SSSP) can be used to enhance polymer properties with and without the addition of nanofillers. The SSSP process employs a modified twin-screw extruder in which the barrel is cooled rather than heated, resulting in the polymer being processed at a temperature below its glass transition temperature, if the polymer is amorphous, or its melt transition temperature, if the polymer is semi-crystalline. The material processed via SSSP experiences high levels of shear and compressive stresses, resulting in many repeated fragmentation and fusion steps during pulverization, which can lead to mechanochemistry. This research provides the first in-depth study on the effect of SSSP processing on the molecular structure as well as physical properties of homopolymers. Rheological characterization has demonstrated an increase in the melt viscosity of pulverized poly(ethylene terephthalate) (PET), which can be ascribed to the in situ formation of lightly branched PET. Further evidence of branched PET is provided via a dramatic increase in the rate of crystallization of the pulverized samples. These results suggest that SSSP processing can enhance the reuse and recyclability of PET. While SSSP processing has dramatic effects on the structure of polyesters and consequently their properties, a mild effect is observed for polyolefins. This thesis also demonstrates via a combination of methods that the well-exfoliated state can be achieved via SSSP processing of various polymer nanocomposites, using as-received, unmodified fillers. For example, extensive comparisons are made concerning the thermal stability in air or nitrogen atmosphere of polypropylene (PP)/clay, PP/graphite, and PP/carbon nanotube (CNT) nanocomposites made by SSSP. These comparisons suggest that the mechanism by which CNTs

  10. Biased versus unbiased randomness in homo-polymers and copolymers of amino acids in the prebiotic world.

    Science.gov (United States)

    Mosqueira, Fernando G; Negron, Alicia; Ramos, Sergio; Polanco, Carlos

    2012-01-01

    The polymerization of amino acids under anhydrous prebiotic conditions was first studied several decades ago. Here we use a stochastic model stressing the relevant role of the polarity of amino acids in the formation of oligopeptides in a prebiotic milieu. Our goal is to outline the predominance of co-polypeptides over homo-polypeptides, resulting not only from the randomness, but also from polarity properties of amino acids. Our results conclude that there was a higher probability of the formation of co-polypeptides than of homo-polymers. Besides, we may hypothesize that the former would have a more ample spectrum of possible chemical functions than homo-polypeptides.

  11. Molecular Differentiated Initiator Reactivity in the Synthesis of Poly(caprolactone-Based Hydrophobic Homopolymer and Amphiphilic Core Corona Star Polymers

    Directory of Open Access Journals (Sweden)

    Eileen Deng

    2015-11-01

    Full Text Available Macromolecules that possess three-dimensional, branched molecular structures are of great interest because they exhibit significantly differentiated application performance compared to conventional linear (straight chain polymers. This paper reports the synthesis of 3- and 4-arm star branched polymers via ring opening polymerisation (ROP utilising multi-functional hydroxyl initiators and Sn(Oct2 as precatalyst. The structures produced include mono-functional hydrophobic and multi-functional amphiphilic core corona stars. The characteristics of the synthetic process were shown to be principally dependent upon the physical/dielectric properties of the initiators used. ROP’s using initiators that were more available to become directly involved with the Sn(Oct2 in the “in-situ” formation of the true catalytic species were observed to require shorter reaction times. Use of microwave heating (MWH in homopolymer star synthesis reduced reaction times compared to conventional heating (CH equivalents, this was attributed to an increased rate of “in-situ” catalyst formation. However, in amphiphilic core corona star formation, the MWH polymerisations exhibited slower propagation rates than CH equivalents. This was attributed to macro-structuring within the reaction medium, which reduced the potential for reaction. It was concluded that CH experiments were less affected by this macro-structuring because it was disrupted by the thermal currents/gradients caused by the conductive/convective heating mechanisms. These gradients are much reduced/absent with MWH because it selectively heats specific species simultaneously throughout the entire volume of the reaction medium. These partitioning problems were overcome by introducing additional quantities of the species that had been determined to selectively heat.

  12. Amphiphilic dendronized homopolymers

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A series of second generation of amphiphilic dendronized homopolymers are efficiently synthesized,and their thermoresponsiveness in aqueous solutions and secondary structures in methanol solutions are described.These polymers are constructed in each repeat unit with various generations of hydrophobic 4-aminoproline and hydrophilic oligoethylene glycol (OEG)-based dendrons,and their over-all hydrophilicity is tuned by varying these dendron generations.Polymers with or without the first generation of proline dendron show good water solubility at room temperature,but exhibit typical thermoresponsive behaviors at elevated temperatures as characterized by turbidity measurements using UV-vis spectroscopy,while the polymer with the secondary generation of proline dendron is not soluble in water.All polymers show ordered secondary structures as evidenced by the optical rotation and circular dichroism experiments.Finally,assembly of these amphiphilic homopolymers into porous films via breath figure (BF) technique is described,and polymer structures are found to show significant influence on the morphology of porous film.

  13. Preparation, loading, and cytotoxicity analysis of polymer nanotubes from an ethylene glycol dimethacrylate homopolymer in comparison to multi‐walled carbon nanotubes

    Science.gov (United States)

    Thomas, Laurent; Zheng, Yu; Steinhart, Martin; Werner, Carsten; Wang, Wenxin

    2016-01-01

    Abstract Despite concerns over toxicity, carbon nanotubes have been extensively investigated for potential applications in nanomedicine because of their small size, unique properties, and ability to carry cargo such as small molecules and nucleic acids. Herein, we show that polymer nanotubes can be synthesized quickly and easily from a homopolymer of ethylene glycol dimethacrylate (EGDMA). The nanotubes formed via photo‐initiated polymerization of the highly functional prepolymer, inside an anodized aluminium oxide template, have a regular structure and large internal pore and can be loaded with a fluorescent dye within minutes representing a simple alternative to multi‐walled carbon nanotubes for biomedical applications. PMID:27512602

  14. Bimodal porous TiO2 structures templated by graft copolymer/homopolymer blend for dye-sensitized solar cells with polymer electrolyte

    Science.gov (United States)

    Kim, Jin Kyu; Lee, Chang Soo; Lee, Sang-Yup; Cho, Hyung Hee; Kim, Jong Hak

    2016-12-01

    Bimodal porous TiO2 (BP-TiO2) with large surface area, high porosity, good interconnectivity, and excellent light-scattering ability are synthesized via a facile one-step method using a self-assembled blend template consisting of an amphiphilic poly(vinyl chloride)-g-poly(oxyethylene methacrylate) (PVC-g-POEM) graft copolymer and a hydrophobic poly(vinyl chloride) (PVC) homopolymer. The hydrophilically surface-modified TiO2 nanoparticles selectively interact with the hydrophilic POEM chains, while the addition of the PVC homopolymer increases the hydrophobic domain size, resulting in the formation of dual pores (i.e., macropores and mesopores). The sizes and numbers of macropores can easily be controlled by changing the molecular weight and amount of the PVC homopolymer. The polymer electrolyte dye-sensitized solar cells (DSSCs) fabricated with BP-TiO2 photoanodes exhibited energy conversion efficiencies of up to 7.6% at 100 mW cm-2, which is much higher than those of mesoporous TiO2 (5.8%) with PVC-g-POEM only and conventional nanocrystalline TiO2 (4.9%) with commercial Dyesol paste. The enhanced energy conversion efficiencies mostly resulted from the light-scattering effects of the macropores, which increased the light-harvesting efficiencies. The improved light-harvesting and photovoltaic performances of the DSSCs were characterized by UV-vis spectroscopy, incident photon-to-current conversion efficiency analysis, electrochemical impedance spectroscopy, intensity-modulated photocurrent spectroscopy, and intensity-modulated photovoltage spectroscopy.

  15. MISCIBILITY IN COPOLYMER/HOMOPOLYMER BLENDS

    Institute of Scientific and Technical Information of China (English)

    JIANG Ming

    1988-01-01

    In order to study the miscibility of a copolymer with its corresponding homopolymers, varieties of multicomponent polymers including simple graft, multibranch, diblock, triblock and four-arm block copolymers and so-called ABCPs were synthesized and characterized. The morphologies of the blends comprising the covolymers and the corresponding homopolymers were examined by electron microscopy. It is concluded that beeides molecular weight, architecture of a copolymers has apparent effect on the miscibility, i.e. the more complex is molecular architecture, the greater is conformation restriction in microdomain formation and the less is solubility of homopolymer in corresponding domains. In addition, a density gradient model is suggested for describing the segment distribution of the bound and free chains in block-homopolymer systems. Using this model, Helfand's theory is extended to the blends of copolymer and homopolymer predicting the miscibility which is in good agreement with the experimental results.

  16. Plant oil-based shape memory polymer using acrylic monolith

    Directory of Open Access Journals (Sweden)

    T. Tsujimoto

    2015-09-01

    Full Text Available This article deals with the synthesis of a plant oil-based material using acrylic monolith. An acrylic monolith bearing oxirane groups was prepared via simple technique that involved the dissolution of poly(glycidyl methacrylate-comethyl methacrylate (PGMA in ethanolic – aqueous solution by heating and subsequent cooling. The PGMA monolith had topologically porous structure, which was attributed to the phase separation of the polymer solution. The PGMA monolith was impregnated by epoxidized soybean oil (ESO containing thermally-latent catalyst, and the subsequent curing produced a crosslinked material with relatively good transparency. The Young’s modulus and the tensile strength of polyESO/PGMA increased compared with the ESO homopolymer. The strain at break of polyESO/PGMA was larger than that of the ESO homopolymer and crosslinked PGMA. Furthermore, polyESO/PGMA exhibited good shape memory-recovery behavior.

  17. Antibacterial Activity of Geminized Amphiphilic Cationic Homopolymers.

    Science.gov (United States)

    Wang, Hui; Shi, Xuefeng; Yu, Danfeng; Zhang, Jian; Yang, Guang; Cui, Yingxian; Sun, Keji; Wang, Jinben; Yan, Haike

    2015-12-22

    The current study is aimed at investigating the effect of cationic charge density and hydrophobicity on the antibacterial and hemolytic activities. Two kinds of cationic surfmers, containing single or double hydrophobic tails (octyl chains or benzyl groups), and the corresponding homopolymers were synthesized. The antimicrobial activity of these candidate antibacterials was studied by microbial growth inhibition assays against Escherichia coli, and hemolysis activity was carried out using human red blood cells. It was interestingly found that the homopolymers were much more effective in antibacterial property than their corresponding monomers. Furthermore, the geminized homopolymers had significantly higher antibacterial activity than that of their counterparts but with single amphiphilic side chains in each repeated unit. Geminized homopolymers, with high positive charge density and moderate hydrophobicity (such as benzyl groups), combine both advantages of efficient antibacterial property and prominently high selectivity. To further explain the antibacterial performance of the novel polymer series, the molecular interaction mechanism is proposed according to experimental data which shows that these specimens are likely to kill microbes by disrupting bacterial membranes, leading them unlikely to induce resistance.

  18. Synthesis, spectral studies, antimicrobial and insect antifeedant potent keto oxiranes

    Directory of Open Access Journals (Sweden)

    Ganesamoorthy Thirunarayanan

    2016-09-01

    Full Text Available A series of ee (αS, βR biphenyl keto oxiranes (biphenyl-4-yl[3-(substituted phenyloxiran-2-yl]methanones have been synthesized by phase transfer catalysed epoxidation of biphenyl 2E-chalcones. The yields of oxiranes are more than 95%. The synthesized oxiranes have been characterized by IR, 1H, 13C and GC–MS spectra. The spectral data are correlated with Hammett substituent constants and Swain–Lupton parameters. From the regression analyses, the effect of substituent on the group frequencies has been predicted. The antimicrobial and insect antifeedant activities of all synthesized oxiranes have been evaluated.

  19. Group Contribution Analysis of the Damping Behavior of Homopolymers, Statistical Copolymers, and Interpenetrating Polymer Networks Based on Acrylic, Vinyl, and Styrenic Mers,

    Science.gov (United States)

    1987-01-01

    Viscoelastomer (Rheovibron DDV-III-C type, Toyo Baldwin Co. Ltd.) coupled with a computer and a plotter (assembled by Imass, Inc.) was 10 used to...537, McGraw-Hill, New York, 1986-87. 45. R. F. Boyer, in "Encyclopedia of Polymer Sceince and Technology," Supplement Vol. 2, p. 745, N. M. Bikales

  20. Review of Preparation and Properties of Polymers from Copolymerization of Aprotic Acrylic Monomers with Protic Acrylic Monomers

    Science.gov (United States)

    1988-07-01

    STRATEGIES APPLICABLE TO POLYMER RESEARCH: DETERMINATION OF HOMOPOLYMER AND COPOLYMER CHEMICAL ABSTRACT SERVICE (CAS) NUMBERS THROUGH DIALOG...8217 APPENDIX A DATA BASE LITERATURE REVIEW STRATEGIES APPLICABLE TO POLYMER RESEARCH: DETERMINATION OF HOMOPOLYMER AND COPOLYMER CHEMICAL ABSTRACT SERVICE

  1. Modification of the morphology of P(S-b-EO) templated thin TiO2 films by swelling with PS homopolymer.

    Science.gov (United States)

    Perlich, J; Schulz, L; Abul Kashem, M M; Cheng, Y-J; Memesa, M; Gutmann, J S; Roth, S V; Müller-Buschbaum, P

    2007-09-25

    For the controlled modification of sol-gel-templated polymer nanocomposites, which are transferred to a nanostructured, crystalline TiO2 phase by a calcination process, the addition of a single homopolymer was investigated. For the preparation, the homopolymer polystyrene (PS) is added in different amounts to the diblock copolymer P(S-b-EO) acting as a templating agent. The homopolymer/diblock copolymer blend system is combined with sol-gel chemistry to provide and attach the TiO2 nanoparticles to the diblock copolymer. So-called good-poor solvent-pair-induced phase separation leads to the formation of nanostructures by film preparation via spin coating. The fabricated morphologies are studied as a function of added homopolymer before and after calcination with atomic force microscopy, field emission scanning electron microscopy, and grazing incidence small-angle X-ray scattering. The observed behavior is discussed in the framework of controlling the block copolymer morphologies by the addition of homopolymers. At small homopolymer concentrations, the increase in homopolymer concentration changes the structure size, whereas at high homopolymer concentrations, a change in morphology is triggered. Thus, the behavior of a pure polymer system is transferred to a more complex hybrid system.

  2. Structure–Conductivity Relationships in Ordered and Disordered Salt-Doped Diblock Copolymer/Homopolymer Blends

    Energy Technology Data Exchange (ETDEWEB)

    Irwin, Matthew T.; Hickey, Robert J.; Xie, Shuyi; So, Soonyong; Bates, Frank S.; Lodge, Timothy P. (UMM)

    2016-11-21

    We examine the relationship between structure and ionic conductivity in salt-containing ternary polymer blends that exhibit various microstructured morphologies, including lamellae, a hexagonal phase, and a bicontinuous microemulsion, as well as the disordered phase. These blends consist of polystyrene (PS, Mn ≈ 600 g/mol) and poly(ethylene oxide) (PEO, Mn ≈ 400 g/mol) homopolymers, a nearly symmetric PS–PEO block copolymer (Mn ≈ 4700 g/mol), and lithium bis(trifluoromethane)sulfonamide (LiTFSI). These pseudoternary blends exhibit phase behavior that parallels that of well-studied ternary polymer blends consisting of A and B homopolymers compatibilized by an AB diblock copolymer. The utility of this framework is that all blends have nominally the same number of ethylene oxide, styrene, Li+, and TFSI– units, yet can exhibit a variety of microstructures depending on the relative ratio of the homopolymers to the block copolymer. For the systems studied, the ratio r = [Li+]/[EO] is maintained at 0.06, and the volume fraction of PS homopolymer is kept equal to that of PEO homopolymer plus salt. The total volume fraction of homopolymer is varied from 0 to 0.70. When heated through the order–disorder transition, all blends exhibit an abrupt increase in conductivity. However, analysis of small-angle X-ray scattering data indicates significant structure even in the disordered state for several blend compositions. By comparing the nature and structure of the disordered states with their corresponding ordered states, we find that this increase in conductivity through the order–disorder transition is most likely due to the elimination of grain boundaries. In either disordered or ordered states, the conductivity decreases as the total amount of homopolymer is increased, an unanticipated observation. This trend with increasing homopolymer loading is hypothesized to result from an increased density of

  3. New oxirane derivatives of 1,4-naphthoquinones and their evaluation against T. cruzi epimastigote forms.

    Science.gov (United States)

    Carneiro, Paula F; do Nascimento, Samara B; Pinto, Antonio V; Pinto, Maria do Carmo F R; Lechuga, Guilherme C; Santos, Dilvani O; dos Santos Júnior, Helvécio M; Resende, Jackson A L C; Bourguignon, Saulo C; Ferreira, Vitor F

    2012-08-15

    New oxirane derivatives were synthesized using six naphthoquinones as the starting materials. Our biological results showed that these oxiranes acted as trypanocidal agents against Trypanosoma cruzi with minimal cytotoxicity in the VERO cell line compared to naphthoquinones. In particular, oxirane derivative 14 showed low cytotoxicity in a mammalian cell line and exhibited better activity against epimastigote forms of T.cruzi than the current drug used to treat Chagas disease, benznidazole.

  4. Spectral correlation, antimicrobial and insect antifeedant activities of some 1-naphthyl keto-oxiranes

    Directory of Open Access Journals (Sweden)

    G. Thirunarayanan

    2014-12-01

    Full Text Available Thirteen optically active (αS,βR 1-naphthyl keto-oxiranes (1-naphthyl-4-yl[3-(substituted phenyloxiran-2-yl]methanones have been synthesised by phase transfer catalysed epoxidation of 1-naphthyl chalcones. The yields of oxiranes are more than 95%. The synthesized oxiranes have been characterized by IR, 1H, 13C and MS spectra. The spectral data are correlated with Hammett substituent constants and Swain–Lupton parameters. From the regression analysis the effect of substituent on the group frequencies has been predicted. The antimicrobial and insect antifeedant activities of all synthesised oxiranes have been evaluated.

  5. SOME ASPECTS OF MORPHOLOGIES AND INTERFACES IN COPOLYMER/HOMOPOLYMER BLENDS

    Institute of Scientific and Technical Information of China (English)

    JIANG Ming; CAO Xianyi; YU Tongyin

    1988-01-01

    Based on a series of morphological studies of blends of homopolymer (Homo) and a variety of block and graft copolymers (Cop), the nature of phase separation, interface, emulsification and inner morphology of copolymer-dispersed phase etc. in the blends are discussed. In the cases of Cop AB/Homo A/Homo B systems,in which one homopolymer forms matrix, it is observed that the dispersed homopolymer phase is exclusively associated with Cop AB, i.e. no Homo A-Homo B interface exists. This phenomenon is believed to be caused by minimizing the interfacial energy of the systems. Meanwhile, preferential solubilization or anchoring of the like chains of copolymer into homopolymer matrix leads to stabilization of the dispersed phase in the matrix.In addition, regular variation of the inner morphology of the dispersed copolymer phase with the composition and molecular parameters of the component polymers is observed. When the two components have comparable proportions, alternating concentric shells are the most common feature which is associated with minimizing the interfacial energy in the Cop/Homo systems.

  6. In-situ polymerized PLOT columns III: divinylbenzene copolymers and dimethacrylate homopolymers

    Science.gov (United States)

    Shen, T. C.; Fong, M. M.

    1994-01-01

    Studies of divinylbenzene copolymers and dimethacrylate homopolymers indicate that the polymer pore size controls the separation of water and ammonia on porous-layer-open-tubular (PLOT) columns. To a lesser degree, the polarity of the polymers also affects the separation of a water-ammonia gas mixture. Our results demonstrate that the pore size can be regulated by controlling the cross-linking density or the chain length between the cross-linking functional groups. An optimum pore size will provide the best separation of water and ammonia.

  7. Neutral wetting brush layers for block copolymer thin films using homopolymer blends processed at high temperatures.

    Science.gov (United States)

    Ceresoli, M; Palermo, M; Ferrarese Lupi, F; Seguini, G; Perego, M; Zuccheri, G; Phadatare, S D; Antonioli, D; Gianotti, V; Sparnacci, K; Laus, M

    2015-10-16

    Binary homopolymer blends of two hydroxyl-terminated polystyrene (PS-OH) and polymethylmethacrylate (PMMA-OH) homopolymers (Mn ∼ 16000 g mol(-1)) were grafted on SiO2 substrates by high-temperature (T > 150 °C), short-time (t layer was tested to screen preferential interactions of the SiO2 substrate with the different symmetric and asymmetric PS-b-PMMA block copolymers deposited on top of the grafted molecules. By properly adjusting the blend composition and the processing parameters, an efficient surface neutralization path was identified, enabling the formation, in the block copolymer film, of homogeneous textures of lamellae or cylinders perpendicularly oriented with respect to the substrate. A critical interplay between the phase segregation of the homopolymer blends and their grafting process on the SiO2 was observed. In fact, the polar SiO2 is preferential for the PMMA-rich phase that forms a homogeneous layer on the substrate, while the PS-rich phase is located at the polymer-air interface. During the thermal treatment, phase segregation and grafting proceed simultaneously. Complete wetting of the PS rich phase on the PMMA rich phase leads to the formation of a PS/PMMA bilayer. In this case, the progressive diffusion of PS chains toward the polymer-SiO2 interface during the thermal treatment allows tuning of the brush layer composition.

  8. Polymer Functionalized Nanoparticles in Polymer Nanocomposites

    Science.gov (United States)

    Jayaraman, Arthi

    2013-03-01

    Significant interest has grown around the ability to control spatial arrangement of nanoparticles in a polymer nanocomposite to engineer materials with target properties. Past work has shown that one could achieve controlled assembly of nanoparticles in the polymer matrix by functionalizing nanoparticle surfaces with homopolymers. This talk will focus on our recent work using Polymer Reference Interaction Site Model (PRISM) theory and Monte Carlo simulations and GPU-based molecular dynamics simulations to specifically understand how heterogeneity in the polymer functionalization in the form of a) copolymers with varying monomer chemistry and monomer sequence, and b) polydispersity in homopolymer grafts can tune effective interactions between functionalized nanoparticles, and the assembly of functionalized nanoparticles.

  9. Controlled self-assembly in homopolymer and diblock copolymer

    Science.gov (United States)

    Zhuang, Lei

    This thesis work studies the process, mechanism and control of self-assembly in homopolymers and diblock copolymers. These studies are aimed at finding novel patterning methods that can lead to low cost lithography technologies capable of creating micrometer to nanometer patterns over a large area. We first present a new phenomenon called Lithographically-Induced Self-Assembly (LISA) that can create ordered arrays of pillars in a homopolymer film with a mask placed close to its surface. We demonstrate that the shape, size and morphology of the ordered pillar arrays can be controlled with a patterned mask. A model is developed based on the instability in a fluidic film induced by the Coulomb force from charge accumulation in the polymer film and the mask. Experimental results are shown to support the model. We also investigate the behavior of defects that destroy the ordering of the LISA array and propose ways to prevent them. This self-assembly phenomenon is used as a patterning technique to define the active area of an organic light emitting diode (OLED). The device shows significantly improved lifetime due to the restriction of defect growth. Another patterning technology that is closely related to LISA, Lithographically-Induced Self-Construction (LISC), is also introduced. LISC can form mesas of polymer from the initial thin film and they inherit the shape and size of the mask patterns. A model based on the dynamics of LISA pillar formation and mass conservation is presented and provides a guideline for choosing LISC process parameters. In the final part of the thesis, we study a technique to control the orientation of diblock copolymer phase separation in a thin film by applying a pressure on the film through a flat mask. The result is a well-ordered grating pattern of the phase separation with a period of tens of nanometers. The effect of pressure and film thickness on the final pattern is investigated by experiments. We suggest that the increased ordering is

  10. Accurate spectroscopic characterization of protonated oxirane: a potential prebiotic species in Titan's atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Puzzarini, Cristina [Dipartimento di Chimica " Giacomo Ciamician," Università di Bologna, Via Selmi 2, I-40126 Bologna (Italy); Ali, Ashraf [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Biczysko, Malgorzata; Barone, Vincenzo, E-mail: cristina.puzzarini@unibo.it [Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa (Italy)

    2014-09-10

    An accurate spectroscopic characterization of protonated oxirane has been carried out by means of state-of-the-art computational methods and approaches. The calculated spectroscopic parameters from our recent computational investigation of oxirane together with the corresponding experimental data available were used to assess the accuracy of our predicted rotational and IR spectra of protonated oxirane. We found an accuracy of about 10 cm{sup –1} for vibrational transitions (fundamentals as well as overtones and combination bands) and, in relative terms, of 0.1% for rotational transitions. We are therefore confident that the spectroscopic data provided herein are a valuable support for the detection of protonated oxirane not only in Titan's atmosphere but also in the interstellar medium.

  11. Composition fluctuations in homopolymer blends and diblock copolymers

    DEFF Research Database (Denmark)

    Frielinghaus, H.; Mortensen, K.; Almdal, K.

    2000-01-01

    The thermal composition fluctuations of a deuterogenous polystyrene/polyethyleneoxide (dPS/PEO) homopolymer blend and corresponding diblock copolymer have been investigated by small angle neutron scattering (SANS). The measured susceptibilities could be described by theories, which take strong...

  12. Wang-Landau sampling for homopolymer collapse

    Science.gov (United States)

    Seaton, Daniel T.; Mitchell, Steven J.; Landau, David P.

    2008-03-01

    We explore the behavior of a continuum-homopolymer model using the Wang-Landau algorithm, concentrating on phase transitions such as the coil-globule and solid-liquid transitions. Using the density of states generated by the Wang-Landau algorithm, we calculate various thermodynamic quantities, e.g., the internal energy and specific heat. We also study how algorithmic parameters, such as sampling boundaries (maximum and minimum energies for random walks) and the final value of the modification factor, affect these quantities. In particular, we observe how the sampling boundaries can significantly alter the transition behavior. Our results are compared with two recent studies that yielded contradictory results, one using the bond-fluctuation model and the other using a continuum model similar to our own. We find that the transitions seen in our model are much more similar to those in the bond-fluctuation study. The careful analysis of the effects of algorithmic parameters on thermodynamic quantities should be relevant to the study of other polymeric/protein models.

  13. Assembly of diblock copolymer grafted nanoparticles in a homopolymer blend matrix

    Science.gov (United States)

    Estridge, Cara; Jayaraman, Arthi

    2014-03-01

    Hybrid materials comprised of nanoscale fillers embedded in a polymer matrix, also terms polymer nanocomposites, are used in many applications, such as photovoltaics, photonics, automobile parts, where their macroscopic properties are governed by the nanocomposite morphology. The structure and composite morphology is controlled by the interactions of the nanoscale fillers and the polymer matrix. In this talk we show using molecular simulations that functionalization of the nanoparticle surface with AB diblock copolymer grafts is a way to tune the interactions between the grafted particle and the A and B homopolymer blend matrix. Specifically, our work demonstrates that by tailoring the copolymer composition and the copolymer grafting density one can tune the location of the copolymer grafted particles in the matrix, (e.g. within a domain versus interface of two domains). Additionally, in the case where the grafted particles locate themselves at the interface between the two domains, the interfacial tension is reduced below that possible with bare ungrafted particles at the interface.

  14. 21 CFR 177.2480 - Polyoxymethylene homopolymer.

    Science.gov (United States)

    2010-04-01

    ...) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use Only as.../610/6 terpolymer, respective proportions of nylon polymers by weight are: 3/2/4 At a maximum level of... Extrusion Materials” (Revised 1966), which is incorporated by reference. Copies are available from...

  15. Hydrophilic porous magnetic poly(GMA-MBAA-NVP) composite microspheres containing oxirane groups: An efficient carrier for immobilizing penicillin G acylase

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Ping; Su, Weiguang, E-mail: weiguangsu@nxu.edu.cn; Gu, Yaohua; Liu, Haifeng; Wang, Julan

    2015-03-15

    Magnetic hydrophilic polymeric microspheres containing oxirane groups were prepared by inverse suspension polymerization of glycidyl methacrylate (GMA), N, N′-methylene bisacrylamide (MBAA) and N-vinyl pyrrolidone (NVP) in the existence of formamide, which were denoted as magnetic poly(GMA-MBAA-NVP) microspheres. The magnetic poly(GMA-MBAA-NVP) microspheres were characterized by scanning electron microscopy (SEM), FT-IR spectroscopy, X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and so on. The results showed that poly(GMA-MBAA-NVP) microspheres possessed well spherical shape, narrow size distribution, abundant porous structure, reactive oxirane groups and superparamagnetic properties. Formamide used in the present work served as a modifier, a dispersant and a porogen to form final porous polymer microspheres. The penicillin G acylase (PGA) was covalently immobilized onto the magnetic microspheres through the reaction between the amino groups of enzyme and the oxirane groups on the microspheres for producing 6-aminopenicillanic acid (6-APA). The effects of GMA/NVP ratio and crosslink density on the activity of immobilized PGA were investigated. The highest apparent activity, enzyme loading and coupling yield of immobilized PGA were 821 IU/g, 65.3 mg/g and 42.3% respectively when the mass ratio of GMA/NVP was 1:1 and crosslink density was 60%. Compared with the free PGA, immobilized PGA showed a wider range of pH value and reaction temperature. The relative activity and reaction rate of immobilized PGA remained almost constant after 20 recycles. The magnetic poly(GMA-MBAA-NVP) microspheres would be very promising carriers for immobilizing enzymes in industrial application. - Highlights: • The magnetic poly(GMA-MBAA-NVP) microspheres were successfully synthesized. • Formamide served as a modifier, a dispersant and a porogen to form microspheres. • The magnetic microspheres were highly efficient carriers for immobilizing PGA. • Immobilized PGA

  16. Pd/C-Catalyzed Carbonylative Esterification of Aryl Halides with Alcohols by Using Oxiranes as CO Sources.

    Science.gov (United States)

    Min, Byul-Hana; Kim, Dong-Su; Park, Hyo-Soon; Jun, Chul-Ho

    2016-04-25

    A carbonylative esterification reaction between aryl bromides and alcohols, promoted by Pd/C and NaF in the presence of oxiranes, has been developed. In this process, oxiranes serve as sources of carbon monoxide by their conversion to aldehydes through a palladium-promoted Meinwald rearrangement pathway. Intramolecular versions of this process serve as methods for the synthesis of lactones and phthalimides.

  17. Mixed time-dependent density-functional theory/classical trajectory surface hopping study of oxirane photochemistry

    NARCIS (Netherlands)

    Tapavicza, Enrico; Tavernelli, Ivano; Rothlisberger, Ursula; Filippi, Claudia; Casida, Mark E.

    2008-01-01

    We present a mixed time-dependent density-functional theory (TDDFT)/classical trajectory surface hopping (SH) study of the photochemical ring opening in oxirane. Previous preparatory work limited to the symmetric CC ring-opening pathways of oxirane concluded that the Tamm-Dancoff approximation (TDA)

  18. Synthesis, spectral studies, antimicrobial, antioxidant and insect antifeedant activities of some 9 H-fluorene-2-yl keto-oxiranes

    Science.gov (United States)

    Thirunarayanan, G.; Vanangamudi, G.

    2011-10-01

    Thirteen ee (α S, β R) 9 H-fluorene-2-yl keto-oxiranes (2-(9 H)-fluorene-4-yl[3-(substituted phenyl)oxiran-2-yl]methanones) have been synthesized by phase transfer catalysed epoxidation of 9 H-fluorene-2-yl chalcones. The yields of oxiranes are more than 95%. The synthesized oxiranes have been characterized by IR, 1H, 13C and GC-MS spectral data. The spectral data are correlated with Hammett substituent constants and Swain-Lupton parameters. From the regression analysis, the effect of substituents on the group frequencies has been predicted. The antimicrobial, antioxidant and insect antifeedant activities of all the synthesized oxiranes have been studied.

  19. Adsorption theory for polydisperse polymers.

    NARCIS (Netherlands)

    Roefs, S.P.F.M.; Scheutjens, J.M.H.M.; Leermakers, F.A.M.

    1994-01-01

    Most polymers are polydisperse. We extend the self-consistent field polymer adsorption theory due to Scheutjens and Fleer to account for an arbitrary polymer molecular weight distribution with a cutoff chain length Nmax. In this paper, the treatment is restricted to homopolymers. For this case a ver

  20. A theoretical study on the mechanism of the reaction between azacyclopropenylidene and oxirane

    Directory of Open Access Journals (Sweden)

    Jing Ying

    2015-01-01

    Full Text Available The reaction mechanism between azacyclopropenylidene and oxirane has been systematically investigated employing the second-order Møller-Plesset perturbation theory (MP2 method to better understand the azacyclopropenylidene reactivity with three-membered ring compound oxirane. Geometry optimization, vibrational analysis, and energy property for the involved stationary points on the potential energy surface have been calculated. Energies of all the species are also further corrected by CCSD(T/6-311+G* single-point calculations. Our calculational results show that there are two possible reaction pathways. From the kinetic viewpoint, the first pathway is primary. From the viewpoint of thermodynamics, the second is dominating.

  1. Wetting of brushes by polymer melts

    NARCIS (Netherlands)

    Maas, J.

    2001-01-01

    The scientific and practical importance of thin polymer films is evident and in many applications polymer films are required. Hence, studying properties of polymer films is relevant. Adsorption of polymer at liquid/solid interfaces can stabilise particles in a matrix. Homopolymers are often used for

  2. Water transport and clustering behavior in homopolymer and graft copolymer polylactide

    Energy Technology Data Exchange (ETDEWEB)

    Du, An; Koo, Donghun; Theryo, Grayce; Hillmyer, Marc A.; Cairncross, Richard A. (Drexel); (UMM)

    2015-02-19

    Polylactide is a bio-based and biodegradable polymer well-known for its renewable origins. Water sorption and clustering behavior in both a homopolymer polylactide and a graft copolymer of polylactide was studied using the quartz crystal microbalance/heat conduction calorimetry (QCM/HCC) technique. The graft copolymer, poly(1,5-cyclooctadiene-co-5-norbornene-2-methanol-graft-D,L-lactide), contained polylactide chains (95 wt.%) grafted onto a hydrophobic rubbery backbone (5 wt.%). Clustering is an important phenomenon in the study of water transport properties in polymers since the presence of water clusters can affect the water diffusivity. The HCC method using the thermal power signals and Van't Hoff's law were both employed to estimate the water sorption enthalpy. Sorption enthalpy of water in both polymers was determined to be approximately -40 kJ/mol for all water activity levels. Zimm-Lundberg analysis showed that water clusters start to form at a water activity of 0.4. The engaged species induced clustering (ENSIC) model was used to curve fit sorption isotherms and showed that the affinity among water molecules is higher than that between water molecules and polymer chains. All the methods used indicate that clustering of water molecules exists in both polymers.

  3. Synthesis of alkyl bis(dimethylamino)methylenecarbamodithioates from 1,1,3,3-tetramethylguanidine, CS2 and oxiranes

    Institute of Scientific and Technical Information of China (English)

    Sima Yavari; Samira Nasiri-Gheidari; Avat (Arman) Taherpour; Issa Yavari

    2012-01-01

    An efficient synthesis of alkyl bis(dimethylamino)methylenecarbamodithioates via a one-pot reaction between 1,1,3,3-tetramethylguanidine,carbon disulfide and substituted oxiranes,in good yields,is described.

  4. Development of a novel oxirane-acrylate composite restorative resin material

    Science.gov (United States)

    Sripathi Panditaradhyula, Anuhya

    The need for resin with a long clinical life can be satiated through the novel formulation of varying concentrations of oxirane and acrylate monomers with an increase in filler loading in the sample, which will allow the creation of a resin that is less susceptible to chemical degradation along with improved mechanical properties. Various concentrations of oxirane and acrylate monomers with a three-component photoinitiation system, which is capable of both free radical (acrylate) and cationic (oxirane) initiation, are used. The resin composites were placed in the Speedmixer for 30 seconds and gravitation convection oven for one minute, repeated 5-7 times. The resin composites were used to create a 9.525 mm diameter * 1.5875 mm thick resin mold. The mold was then photocured for twenty seconds on both sides using VALO blue LED light. The Rockwell hardness and shore D durometer hardness served as relative measures of bonding between the monomers. The ideal formulation of oxirane and acrylate concentrations were used to perform the Instron 3 point bend test, as well as contact angle determination. The goal is to identify a resin with a clinical life twice that of the resins being used in practice. Potential findings include ideal oxirane and acrylate concentrations with the highest shore D durometer hardness, Rockwell hardness, contact angle values, and Instron 3 point bend test values. Ideal color, transparency and properties of the resin are taken into account. Optimization of oxirane and acrylate monomers, impact while using various filler components (salination, number of fillers), filler particle size variations and variations in using different filler concentrations are observed. Results of using micro and nano-sized monomers are also studied. Addition of fluorinated acrylate monomer to the micro and nano composite was the next goal. A comparison of all the above stated compositions to the control group 70/30 BisTEG was done. A study on the degradation behavior

  5. Extremely asymmetric phase diagram of homopolymer-monotethered nanoparticles: Competition between chain conformational entropy and particle steric interaction

    Science.gov (United States)

    Zhang, Tiancai; Fu, Chao; Yang, Yingzi; Qiu, Feng

    2017-02-01

    The phase behaviors of homopolymer-monotethered nanoparticles (HMNs) in melt are investigated via a theoretical method combining self-consistent field theory for polymers and density functional theory for hard spheres. An extremely asymmetric phase diagram is observed: (i) microphases are only possible for the volume fraction of the tethered polymer fA > 0.35; (ii) in addition to lamellar phase, the system can only self-assemble into various morphologies with a polymer-rich matrix, including gyroid phase, cylindrical phase, and spherical phase. In the frame of this theory, the critical point for HMNs' microphase separation is significantly lower than that of linear diblock copolymers. Furthermore, the characteristic length of microphase-separated structures of HMNs is much smaller than that of linear diblock copolymers with the same molecular weight. Our calculation results on morphologies and characteristic length agree well with recent simulations and experimental observations.

  6. Optimization of the oxirane ring opening reaction in biolubricant base oil production

    Directory of Open Access Journals (Sweden)

    Jumat Salimon

    2016-11-01

    Full Text Available This study has successfully optimized the conversion of monoepoxide linoleic acid (MEOA into biolubricant via oxirane ring opening reaction using oleic acid (OA with p-toluene sulfonic acid (PTSA as a catalyst. The four main factors were studied according to a D-optimal design at three levels. These factors were OA/MEOA ratio, PTSA/MEOA ratio, temperature and reaction time. This analysis evidenced the best operating conditions of the oxirane ring opening reaction performed at the following condition; OA/MEOA ratio of 0.30:1 (w/w, PTSA/MEOA ratio of 0.50:1 (w/w, reaction temperature at 110 °C and reaction time at 4.5 h, an optimum yield of 84.61% and OOC of 0.05%. This model results showed a good agreement with the predict value, demonstrating that this methodology may be useful for industrial process optimization.

  7. Synthetic polymers and methods of making and using the same

    Energy Technology Data Exchange (ETDEWEB)

    Daily, Michael D.; Grate, Jay W.; Mo, Kai-For

    2016-06-14

    Monomer embodiments that can be used to make polymers, such as homopolymers, heteropolymers, and that can be used in particular embodiments to make sequence-defined polymers are described. Also described are methods of making polymers using such monomer embodiments. Methods of using the polymers also are described.

  8. Synthetic polymers and methods of making and using the same

    Energy Technology Data Exchange (ETDEWEB)

    Grate, Jay W.; Mo, Kai-For; Daily, Michael D.

    2017-02-07

    Monomer embodiments that can be used to make polymers, such as homopolymers, heteropolymers, and that can be used in particular embodiments to make sequence-defined polymers are described. Also described are methods of making polymers using such monomer embodiments. Methods of using the polymers also are described.

  9. Ring-Opening of Oxiranes using Taeniolite-Supported Tris(β-DiketonatoZirconium

    Directory of Open Access Journals (Sweden)

    Yessi Permana

    2012-11-01

    Full Text Available A series of tris(β-diketonatozirconium(IV complexes were immobilized into a synthetic clay structure of Taeniolite by an ion-exchange method to generate organic/inorganic hybrid compounds. The hybrid compound served as a good catalyst for ring-opening reactions of methyl, ethyl, and dimethyl oxiranes with various alcohols to generate primary alkoxy alcohols in appreciable selectivity. This method described a technique to immobilize cationic zirconium complexes without losing selectivity.

  10. Effects of Stiffness on Short, Semiflexible Homopolymer Chains

    Science.gov (United States)

    Seaton, Daniel T.; Schnabel, Stefan; Bachmann, Michael; Landau, David P.

    2012-08-01

    Conformational and transition behavior of finite, semiflexible homopolymers is studied using an extension of the Wang-Landau algorithm. Generation of a flat distribution in the sampling parameters energy and stiffness allows for efficient investigation of transitions between various conformational phases. Of particular importance is the ability to predict behavior for a given stiffness value, where three classes of minimum energy conformations are expected: Solid-globular, rod-like and toroidal. We present first results highlighting the behavior of a single N = 20 length chain.

  11. Isotropic Lifshitz behavior in block copolymer-homopolymer blends

    DEFF Research Database (Denmark)

    Bates, F.S.; Maurer, W.; Lodge, T.P.

    1995-01-01

    A series of mixtures composed of a symmetric A-B diblock copolymer and a symmetric blend of A and B homopolymers was investigated by small-angle neutron scattering. Mean-field theory predicts that a line of lamellar-disorder transitions with wave-vector instability q* > 0 will meet a line...... of critical points with q* = 0 in the three-component mixture at an isotropic Lifshitz point. Mean-field Lifshitz behavior (gamma = 1 and nu = 1/4) was observed in the disordered state at the anticipated composition to within 1 K of the phase transition....

  12. 40 CFR 721.10133 - 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer.

    Science.gov (United States)

    2010-07-01

    ...-hydroxyethyl ester, homopolymer. 721.10133 Section 721.10133 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.10133 2-Propenoic acid, 2-methyl, 2-hydroxyethyl ester... identified as 2-propenoic acid, 2-methyl, 2-hydroxyethyl ester, homopolymer (PMN P-07-401; CAS No....

  13. 21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.

    Science.gov (United States)

    2010-04-01

    ... carboxymethylcellulose sodium denture adhesive. 872.3410 Section 872.3410 Food and Drugs FOOD AND DRUG ADMINISTRATION....3410 Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive is a...

  14. Low band gap polymers for organic photovoltaics

    DEFF Research Database (Denmark)

    Bundgaard, Eva; Krebs, Frederik C

    2007-01-01

    Low band gap polymer materials and their application in organic photovoltaics (OPV) are reviewed. We detail the synthetic approaches to low band gap polymer materials starting from the early methodologies employing quinoid homopolymer structures to the current state of the art that relies...... in photovoltaic applications and give a tabular overview of rarely applied materials....

  15. Dynamics in Adsorbed Homopolymer Layers: Entanglements and Osmotic Effects

    Science.gov (United States)

    Santore, Maria; Mubarekyan, Ervin

    2001-03-01

    This work seeks the dynamic mechanism for the exchange of homopolymer chains between a dilute solution and a layer adsorbed at the solid-liquid interface. With the model system of polyethylene oxide (PEO) adsorbed onto silica from aqueous solution, it is shown that the behavior of saturated interfaces compared to starved layers reveals an interesting trend: The characteristic self exchange time is dependent only on coverage, not molecular weight, for chains of 100K or less. Therefore, it is concluded that classical entanglements do not play a role below 100K. For all molecular weights, when the coverage of 0.2 mg/m2 is exceeded, the interfacial dynamics become slow. At lower coverages, chains lie flat in train, with no loops or tails, and no lateral interactions either. The onset of slow dynamics at higher coverages may be a result of both surface crowding and the resistance of loops and tails to new chains approaching the layer.

  16. Interfacial properties of statistical copolymer brushes in contact with homopolymer melts.

    Science.gov (United States)

    Trombly, David M; Pryamitsyn, Victor; Ganesan, Venkat

    2011-04-21

    We use polymer self-consistent field theory to quantify the interfacial properties of random copolymer brushes (AB) in contact with a homopolymer melt chemically identical to one of the blocks (A). We calculate the interfacial widths and interfacial energies between the melt and the brush as a function of the relative chain sizes, grafting densities, compositions of the random copolymer in the brush, and degree of chemical incompatibility between the A and B species. Our results indicate that the interfacial energies between the melt and the brush increase (signifying expulsion of the free chains from the brush) with increasing grafting density, chemical incompatibility between A and B components, and size of the free chains relative to the grafted chains. We also compare the interfacial energies of random copolymers of different sequence characteristics and find that, except for the case of very blocky or proteinlike chains, blockiness of the copolymer has only little effect on interfacial properties. Our results for interfacial energies are rationalized based on the concept of an "effective volume fraction" of the brush copolymers, f(eff), which quantifies the chemical composition of the brush segments in the interfacial zone between the brush and melt copolymers. Using this concept, we modify the strong-stretching theory of brush-melt interfaces to arrive at a simple model whose results qualitatively agree with our results from self-consistent field theory. We discuss the ramifications of our results for the design of neutral surfaces.

  17. Crystal structure of (R)-6-fluoro-2-[(S)-oxiran-2-yl]chroman.

    Science.gov (United States)

    Rousselin, Yoann; Laureano, Hugo; Clavel, Alexandre

    2015-08-01

    The title compound, C11H11FO2, is a building block in the synthesis of the active pharmaceutical ingredient dl-nebivolol. The synthesis starting from the enanti-omerically pure (R)-6-fluoro-4-oxo-3,4-di-hydro-2H-chromene-2-carb-oxy-lic acid resulted in a mixture of two stereoisomers, namely (R)-6-fluoro-2-[(S)-oxiran-2-yl]chroman and (R)-6-fluoro-2-[(R)-oxiran-2-yl]chroman. The mixture was separated by column chromatography but only one stereoisomer crystallized. The X-ray structure analysis revealed that the solid consisted of the R,S isomer. A similar procedure was repeated for (S)-6-fluoro-4-oxo-3,4-di-hydro-2H-chromene-2-carb-oxy-lic acid and, in this case, the S,R isomer was produced as a crystalline solid. Thus, all four stereoisomers of the title epoxide were obtained and their absolute configuration was assigned. The crystal studied was refined as an inversion twin.

  18. Polymer Basics: Classroom Activities Manipulating Paper Clips to Introduce the Structures and Properties of Polymers

    Science.gov (United States)

    Umar, Yunusa

    2014-01-01

    A simple and effective hands-on classroom activity designed to illustrate basic polymer concepts is presented. In this activity, students build primary structures of homopolymers and different arrangements of monomers in copolymer using paper clips as monomers. The activity supports formation of a basic understanding of polymer structures,…

  19. Polymer Basics: Classroom Activities Manipulating Paper Clips to Introduce the Structures and Properties of Polymers

    Science.gov (United States)

    Umar, Yunusa

    2014-01-01

    A simple and effective hands-on classroom activity designed to illustrate basic polymer concepts is presented. In this activity, students build primary structures of homopolymers and different arrangements of monomers in copolymer using paper clips as monomers. The activity supports formation of a basic understanding of polymer structures,…

  20. 40 CFR 721.10152 - Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica...

    Science.gov (United States)

    2010-07-01

    ...-, hydrolysis products with alkanol zirconium(4+) salt and silica, acetates (generic). 721.10152 Section 721... Oxirane, substituted silylmethyl-, hydrolysis products with alkanol zirconium(4+) salt and silica... zirconium(4+) salt and silica, acetates (PMN P-07-674) is subject to reporting under this section for...

  1. Synthesis of New Quinoxalines Containing an Oxirane Ring by the TDAE Strategy and in Vitro Evaluation in Neuroblastoma Cell Lines

    Directory of Open Access Journals (Sweden)

    Marc Montana

    2014-09-01

    Full Text Available Neuroblastoma is an aggressive pediatric malignancy with significant chemotherapeutic resistance. In order to obtain new compounds active on neuroblastoma cell lines, we investigated the reactivity of carbanion formed via TDAE in quinoxaline series. The new synthesized compounds were tested for their anti-proliferative activity on two neuroblastoma cell lines, and seven oxirane derivatives obtained interesting activities.

  2. A copper(I)-catalyzed reaction of 2-(2-ethynylphenyl)oxirane, sulfonyl azide, with 2-isocyanoacetate.

    Science.gov (United States)

    Li, Shaoyu; Wu, Jie

    2012-09-14

    A novel and straightforward synthetic protocol for the efficient construction of 3',5'-dihydro-1H-spiro[benzo[d]oxepine-2,4'-imidazoles] through a copper(I)-catalyzed reaction between 2-(2-ethynylphenyl)oxirane, sulfonyl azide, and 2-isocyanoacetate is described.

  3. Rheology of Supramolecular Polymers

    DEFF Research Database (Denmark)

    Shabbir, Aamir

    efficient processes or biomedical areas. Design and development of supramolecular polymers using ionic, hydrogen bonding or transition metal complexes with tailored properties requires deep understanding of dynamics both in linear and non-linear deformations. While linear rheology is important to understand......) hydrogen bonding polymers, and (b) ionic bonding polymers (hereafter termed as ionomers). We study linear and non-linear rheology fora model system of entangled pure poly(n-butyl acrylate), PnBA, homopolymer andfour poly(acrylic acid), PnBA-PAA, copolymers with varying AA side groups synthesizedvia...

  4. Optic and catalytic properties of gold nanoparticles tuned by homopolymers

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Gold nanoparticles (GNs) are prepared through in situ reduction using NaBH4 in the presence of homopolymer PDMAEMA. The sizes of the GNs can be adjusted by alternating the molar ratio of gold to DMAEMA. Pure PDMAEMA aqueous solution shows a phase-transition at 50℃ at pH 10 and 25℃ at pH 14, while PDMAEMA-supported GNs aqueous solution shows a phase-transition at 47℃ at pH 10 because of the increasing hydrophobic property resulting from GNs. Due to the pH and tempera-ture-responsible characteristics of PDMAEMA, the resulting PDMAEMA-supported GNs exhibit pH adjustable temperature-responsive characteristics in optic and catalytic aspects. Under an acidic condi-tion (pH 2), the GNs show unchanged surface Plasmon absorbance with a peak of 518 nm in a tem-perature range from 20 to 65℃. Under a basic condition (pH 10), the GNs first show the same absorb-ance with a peak at 518 nm in a temperature range from 20 to 40℃, and then the absorbance red shifts from 518 to 545 nm as temperature increases from 40 to 65℃. When the GNs are used as catalysts to catalyze the reduction of p-nitrophenol, the catalytic activity can be adjusted by changing the permeation of reactants in the PDMAEMA layer at low and high temperatures, respectively.

  5. Dynamic self-consistent field theory for unentangled homopolymer fluids

    Science.gov (United States)

    Mihajlovic, Maja; Lo, Tak Shing; Shnidman, Yitzhak

    2005-10-01

    We present a lattice formulation of a dynamic self-consistent field (DSCF) theory that is capable of resolving interfacial structure, dynamics, and rheology in inhomogeneous, compressible melts and blends of unentangled homopolymer chains. The joint probability distribution of all the Kuhn segments in the fluid, interacting with adjacent segments and walls, is approximated by a product of one-body probabilities for free segments interacting solely with an external potential field that is determined self-consistently. The effect of flow on ideal chain conformations is modeled with finitely extensible, nonlinearly elastic dumbbells in the Peterlin approximation, and related to stepping probabilities in a random walk. Free segment and stepping probabilities generate statistical weights for chain conformations in a self-consistent field, and determine local volume fractions of chain segments. Flux balance across unit lattice cells yields mean field transport equations for the evolution of free segment probabilities and of momentum densities on the Kuhn length scale. Diffusive and viscous contributions to the fluxes arise from segmental hops modeled as a Markov process, with transition rates reflecting changes in segmental interaction, kinetic energy, and entropic contributions to the free energy under flow. We apply the DSCF equations to study both transient and steady-state interfacial structure, flow, and rheology in a sheared planar channel containing either a one-component melt or a phase-separated, two-component blend.

  6. Impacts of Repeat Unit Structure and Copolymer Architecture on Thermal and Solution Properties in Homopolymers, Copolymers, and Copolymer Blends

    Science.gov (United States)

    Marrou, Stephen Raye

    Gradient copolymers are a relatively new type of copolymer architecture in which the distribution of comonomers gradually varies over the length of the copolymer chain, resulting in a number of unusual properties derived from the arrangement of repeat units. For example, nanophase-segregated gradient copolymers exhibit extremely broad glass transition temperatures (Tgs) resulting from the wide range of compositions present in the nanostructure. This dissertation presents a number of studies on how repeat unit structure and copolymer architecture dictate bulk and solution properties, specifically taking inspiration from the gradient copolymer architecture and comparing the response from this compositionally heterogeneous material to other more conventional materials. The glass transition behavior of a range of common homopolymers was studied to determine the effects of subunit structure on Tg breadth, observing a significant increase in T g breadth with increasing side chain length in methacrylate-based homopolymers and random copolymers. Additionally, increasing the composition distribution of copolymers, either by blending individual random copolymers of different overall composition or synthesizing random copolymers to high conversion, resulted in significant increases to Tg breadth. Plasticization of homopolymers and random copolymers with low molecular weight additives also served to increase the Tg breadth; the most dramatic effect was observed in the selective plasticization of a styrene/4-vinylpyridine gradient copolymer with increases in T g breadth to values above 100 °C. In addition, the effects of repeat unit structure and copolymer architecture on other polymer properties besides Tg were also investigated. The intrinsic fluorescence of styrene units in styrene-containing copolymers was studied, noting the impact of repeat unit structure and copolymer architecture on the resulting fluorescence spectra in solution. The impact of repeat unit structure on

  7. Continuum formulation of the Scheutjens-Fleer lattice statistical theory for homopolymer adsorption from solution

    Science.gov (United States)

    Mavrantzas, Vlasis G.; Beris, Antony N.; Leermakers, Frans; Fleer, Gerard J.

    2005-11-01

    Homopolymer adsorption from a dilute solution on an interacting (attractive) surface under static equilibrium conditions is studied in the framework of a Hamiltonian model. The model makes use of the density of chain ends n1,e and utilizes the concept of the propagator G describing conformational probabilities to locally define the polymer segment density or volume fraction φ; both n1,e and φ enter into the expression for the system free energy. The propagator G obeys the Edwards diffusion equation for walks in a self-consistent potential field. The equilibrium distribution of chain ends and, consequently, of chain conformational probabilities is found by minimizing the system free energy. This results in a set of model equations that constitute the exact continuum-space analog of the Scheutjens-Fleer (SF) lattice statistical theory for the adsorption of interacting chains. Since for distances too close to the surface the continuum formulation breaks down, the continuum model is here employed to describe the probability of chain configurations only for distances z greater than 2l, where l denotes the segment length, from the surface; instead, for distances z ⩽2l, the SF lattice model is utilized. Through this novel formulation, the lattice solution at z =2l provides the boundary condition for the continuum model. The resulting hybrid (lattice for distances z ⩽2l, continuum for distances z >2l) model is solved numerically through an efficient implementation of the pseudospectral collocation method. Representative results obtained with the new model and a direct application of the SF lattice model are extensively compared with each other and, in all cases studied, are found to be practically identical.

  8. Methyl 2-methyl-4-(oxiran-2-ylmethoxy-2H-1,2-benzothiazine-3-carboxylate 1,1-dioxide

    Directory of Open Access Journals (Sweden)

    Matloob Ahmad

    2010-02-01

    Full Text Available In the title compound, C14H15NO6S, the thiazine ring adopts a distorted half-chair conformation. The structure displays several cooperative weak intermolecular C—H...O hydrogen-bonding interactions, giving rise to a two-dimensional sheet packing motif. The CH2 group in the methoxy linker to the oxirane ring, and the CH group in that ring, exhibit twofold positional disorder. The three-membered oxirane ring is twisted approximately perpendicular with respect to thiazine ring (dihedral angle = 60/86° for the major/minor disorder components. 1,2-Benzothiazines of this kind have a wide range of biological activities and are mainly used as medicines in the treatment of inflammation and rheumatoid arthritis.

  9. Wavelet treatment of the intrachain correlation functions of homopolymers in dilute solutions

    Science.gov (United States)

    Fedorov, M. V.; Chuev, G. N.; Kuznetsov, Yu. A.; Timoshenko, E. G.

    2004-11-01

    Discrete wavelets are applied to the parametrization of the intrachain two-point correlation functions of homopolymers in dilute solutions obtained from Monte Carlo simulations. Several orthogonal and biorthogonal basis sets have been investigated for use in the truncated wavelet approximation. The quality of the approximation has been assessed by calculation of the scaling exponents obtained from the des Cloizeaux ansatz for the correlation functions of homopolymers with different connectivities in a good solvent. The resulting exponents are in better agreement with those from recent renormalization group calculations as compared to the data without the wavelet denoising. We also discuss how the wavelet treatment improves the quality of data for correlation functions from simulations of homopolymers at varied solvent conditions and of heteropolymers.

  10. Pressure and temperature effects in homopolymer blends and diblock copolymers

    DEFF Research Database (Denmark)

    Frielinghaus, H.; Schwahn, D.; Mortensen, K.;

    1997-01-01

    fluctuations. Phase boundaries, the Flory-Huggins interaction parameter and the Ginzburg number were obtained. The packing of the molecules changes with pressure. Therefore, the degree of thermal fluctuation as a function of packing and temperature was studied. While in polymer blends packing leads, in some...... of the entropic and of the enthalpic parts, respectively, of the Flory-Huggins interaction parameter....

  11. Phase Equilibria and Transition in Mixtures of a Homopolymer and a Block Copolymer. II.

    Science.gov (United States)

    1983-01-26

    AD-A124 929 PHASE EQUILIBRIA AND TRANSITION IN MIXTURES OF A In- NOMOPOLYMER AND’A BLOCK..(U) CINCINNATI UNJY ON DEPT OF MATERIALS SCIENCE AND...REPORT NO. 7 v2 L Phase Equilibria and Transition in Mixtures of a Homopolymer and a Block Copolymer II. The Phase Diagram by R. J. Roe and W. C. Zin...homopolymers as in our systems. The phase equilibria at temperatures above the "pseudo-triple point" BCD can be interpreted in terms of the free energy of

  12. Accurate spectroscopic characterization of oxirane: A valuable route to its identification in Titan's atmosphere and the assignment of unidentified infrared bands

    Energy Technology Data Exchange (ETDEWEB)

    Puzzarini, Cristina [Dipartimento di Chimica " Giacomo Ciamician," Università di Bologna, Via Selmi 2, I-40126 Bologna (Italy); Biczysko, Malgorzata; Bloino, Julien; Barone, Vincenzo, E-mail: cristina.puzzarini@unibo.it [Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa (Italy)

    2014-04-20

    In an effort to provide an accurate spectroscopic characterization of oxirane, state-of-the-art computational methods and approaches have been employed to determine highly accurate fundamental vibrational frequencies and rotational parameters. Available experimental data were used to assess the reliability of our computations, and an accuracy on average of 10 cm{sup –1} for fundamental transitions as well as overtones and combination bands has been pointed out. Moving to rotational spectroscopy, relative discrepancies of 0.1%, 2%-3%, and 3%-4% were observed for rotational, quartic, and sextic centrifugal-distortion constants, respectively. We are therefore confident that the highly accurate spectroscopic data provided herein can be useful for identification of oxirane in Titan's atmosphere and the assignment of unidentified infrared bands. Since oxirane was already observed in the interstellar medium and some astronomical objects are characterized by very high D/H ratios, we also considered the accurate determination of the spectroscopic parameters for the mono-deuterated species, oxirane-d1. For the latter, an empirical scaling procedure allowed us to improve our computed data and to provide predictions for rotational transitions with a relative accuracy of about 0.02% (i.e., an uncertainty of about 40 MHz for a transition lying at 200 GHz).

  13. Thin films of photoactive polymer blends.

    Science.gov (United States)

    Ruderer, Matthias A; Metwalli, Ezzeldin; Wang, Weinan; Kaune, Gunar; Roth, Stephan V; Müller-Buschbaum, Peter

    2009-03-09

    The morphology inside photoactive blended films of two conjugated homopolymers poly [(1-methoxy)-4-(2-ethylhexyloxy)-p-phenylene-vinylene] (MEH-PPV) and poly(3-hexylthiophene-2,5-diyl) (P3HT) is investigated. For both homopolymers a linear dependence of the installed film thickness from the concentration of the polymer solution used in spin coating is probed. This dependence allows preparation of an efficient series of blended films with constant thickness and different blending ratios. Information about the lateral structure inside the films is gained from grazing incidence small angle X-ray scattering. At the calculated critical blending ratio the smallest lateral separation between adjacent domains is found representing the highest surface contact between both homopolymers in the films. The presence of wetting layers at both interfaces as detected with X-ray reflectivity and atomic force microscopy is promising for photovoltaic applications. UV/Vis spectroscopy complements the structural investigation.

  14. The effect of chain stiffness on the phase behaviour of isolated homopolymers

    NARCIS (Netherlands)

    Doye, J.P.K.; Frenkel, D.

    1998-01-01

    We have studied the thermodynamics of isolated homopolymer chains of varying stiffness using a lattice model. A complex phase behaviour is found; phases include chain-folded ‘‘crystalline’’ structures, the disordered globule and the coil. It is found, in agreement with recent theoretical calculation

  15. 40 CFR 721.538 - Phenol, 4-(1,1-dimethyl- ethyl)-, homopolymer.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phenol, 4-(1,1-dimethyl- ethyl... Specific Chemical Substances § 721.538 Phenol, 4-(1,1-dimethyl- ethyl)-, homopolymer. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as phenol,...

  16. 40 CFR 721.5500 - 7-Oxabicyclo[4.1.0]heptane, 3-ethenyl, homopolymer, ether with 2-ethyl-2-(hydroxymethyl)-1,3-pro...

    Science.gov (United States)

    2010-07-01

    ..., homopolymer, ether with 2-ethyl-2-(hydroxymethyl)-1,3-pro-pane-diol (3:1), epoxidized. 721.5500 Section 721...-Oxabicyclo heptane, 3-ethenyl, homopolymer, ether with 2-ethyl-2-(hydroxymethyl)-1,3-pro-pane-diol (3:1... 7-oxabicyclo heptane, 3-ethenyl, homopolymer, ether with 2-ethyl-2(hydroxymethyl)-1,3-propanediol...

  17. 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.

  18. Theory and Simulation Studies of Copolymer Functionalized Nanoparticles in Polymer Nanocomposites

    Science.gov (United States)

    Jayaraman, Arthi; Nair, Nitish; Seifpour, Arezou; Spicer, Philip

    2010-03-01

    Significant interest has grown around the ability to create polymer nanocomposites with controlled spatial arrangement of nanoparticles mediated by a polymer matrix. By functionalizing or grafting polymers on to nanoparticle surfaces and systematically tuning the composition, chemistry, molecular weight and grafting density of the functionalized polymers we can tailor the inter-particle interactions and precisely control the assembly/dispersion of the particles in the polymer matrix. While prior experimental and theoretical work in this area has mostly been on homopolymer grafted particles at high brush-like grafting densities, we study copolymer grafted nanoparticles at low grafting densities in a homopolymer matrix. Using an integrated approach involving Polymer Reference Interaction Site Model (PRISM) theory and Monte Carlo simulations we will present the effect of monomer sequence and molecular weight of the grafted copolymer, compatibility of the graft and matrix polymers, and nanoparticle size on the conformations of the grafted polymers, and the effective interactions between the grafted nanoparticles in the matrix.

  19. Synthesis and characterization of homopolymers bearing acid-cleavable cationic side-chains for pH-modulated release of DNA.

    Science.gov (United States)

    Xu, Zhangyan; Lai, Junping; Tang, Rupei; Ji, Weihang; Wang, Rui; Wang, Jun; Wang, Chun

    2014-07-01

    A new type of homopolymers, PMAOE, bearing acid-cleavable cationic side-chains is synthesized and characterized. PMAOE is obtained via free radical polymerization, and they could efficiently bind and condense plasmid DNA at neutral pH. The strength of DNA binding is dependent on the length of PMAOE chains. NMR analysis reveals that hydrolysis of the ortho ester group of PMAOE follows an exocyclic mechanism and the rate of hydrolysis is much accelerated at mildly acidic pH, leading to accelerated disruption of polyplexes and release of DNA in mildly acidic environment. PMAOE is not toxic to cultured NIH 3T3 and COS-7 cells measured by MTT. This study demonstrates a unique mechanism of achieving pH-modulated binding and release of DNA from polymers with potential applications for gene delivery.

  20. Identifying and tracing potential energy surfaces of electronic excitations with specific character via their transition origins: application to oxirane.

    Science.gov (United States)

    Li, Jian-Hao; Zuehlsdorff, T J; Payne, M C; Hine, N D M

    2015-05-14

    We show that the transition origins of electronic excitations identified by quantified natural transition orbital (QNTO) analysis can be employed to connect potential energy surfaces (PESs) according to their character across a wide range of molecular geometries. This is achieved by locating the switching of transition origins of adiabatic potential surfaces as the geometry changes. The transition vectors for analysing transition origins are provided by linear response time-dependent density functional theory (TDDFT) calculations under the Tamm-Dancoff approximation. We study the photochemical CO ring opening of oxirane as an example and show that the results corroborate the traditional Gomer-Noyes mechanism derived experimentally. The knowledge of specific states for the reaction also agrees well with that given by previous theoretical work using TDDFT surface-hopping dynamics that was validated by high-quality quantum Monte Carlo calculations. We also show that QNTO can be useful for considerably larger and more complex systems: by projecting the excitations to those of a reference oxirane molecule, the approach is able to identify and analyse specific excitations of a trans-2,3-diphenyloxirane molecule.

  1. 2-Amino-3-(Oxirane-2,3-Dicarboxamido)-Propanoyl-Valine, an Effective Peptide Antibiotic from the Epiphyte Pantoea agglomerans 48b/90 ▿

    Science.gov (United States)

    Sammer, Ulrike F.; Völksch, Beate; Möllmann, Ute; Schmidtke, Michaela; Spiteller, Peter; Spiteller, Michael; Spiteller, Dieter

    2009-01-01

    The epiphyte Pantoea agglomerans 48b/90, which has been isolated from soybean leaves, belongs to the Enterobacteriaceae, as does the plant pathogen Erwinia amylovora, which causes fire blight on rosaceous plants such as apples and leads to severe economic losses. Since P. agglomerans efficiently antagonizes phytopathogenic bacteria, the P. agglomerans strain C9-1 is used as a biocontrol agent (BlightBan C9-1). Here we describe the bioassay-guided isolation of a peptide antibiotic that is highly active against the plant pathogen E. amylovora and pathovars of Pseudomonas syringae, and we elucidate its structure. Bioassay-guided fractionation using anion-exchange chromatography followed by hydrophobic interaction liquid chromatography yielded the bioactive, highly polar antibiotic. The compound was identified as 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine by using high-resolution electrospray ionization mass spectrometry and nuclear magnetic resonance techniques. This peptide was found to be produced by three of the nine P. agglomerans strains analyzed. Notably, the biocontrol strain P. agglomerans C9-1 also produces 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine. Previously, 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine has been characterized only from Serratia plymuthica. 2-Amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine has been shown to inhibit the growth of the human pathogen Candida albicans efficiently, but its involvement in the defense of epiphytes against phytopathogenic bacteria has not been investigated so far. PMID:19820144

  2. QM/MM Studies of the Matrix Metalloproteinase 2 (MMP2) Inhibition Mechanism of (S)-SB-3CT and its Oxirane Analogue.

    Science.gov (United States)

    Zhou, Jia; Tao, Peng; Fisher, Jed F; Shi, Qicun; Mobashery, Shahriar; Schlegel, H Bernhard

    2010-11-09

    SB-3CT, (4-phenoxyphenylsulfonyl)methylthiirane, is a potent, mechanism-based inhibitor of the gelatinase sub-class of the matrix metalloproteinase (MMP) family of zinc proteases. The gelatinase MMPs are unusual in that there are several examples where both enantiomers of a racemic inhibitor have comparable inhibitory abilities. SB-3CT is one such example. Here, the inhibition mechanism of the MMP2 gelatinase by the (S)-SB-3CT enantiomer and its oxirane analogue is examined computationally, and compared to the mechanism of (R)-SB-3CT. Inhibition of MMP2 by (R)-SB-3CT was shown previously to involve enzyme-catalyzed C-H deprotonation adjacent to the sulfone, with concomitant opening by β-elimination of the sulfur of the three-membered thiirane ring. Similarly to the R enantiomer, (S)-SB-3CT was docked into the active site of MMP2, followed by molecular dynamics simulation to prepare the complex for combined quantum mechanics and molecular mechanics (QM/MM) calculations. QM/MM calculations with B3LYP/6-311+G(d,p) for the QM part (46 atoms) and the AMBER force field for the MM part were used to compare the reaction of (S)-SB-3CT and its oxirane analogue in the active site of MMP2 (9208 atoms). These calculations show that the barrier for the proton abstraction coupled ring opening reaction of (S)-SB-3CT in the MMP2 active site is 4.4 kcal/mol lower than its oxirane analogue, and the ring opening reaction energy of (S)-SB-3CT is only 1.6 kcal/mol less exothermic than its oxirane analogue. Calculations also show that the protonation of the ring-opened products by water is thermodynamically much more favorable for the alkoxide obtained from the oxirane, than for the thiolate obtained from the thiirane. In contrast to (R)-SB-3CT and the R-oxirane analogue, the double bonds of the ring-opened products of (S)-SB-3CT and its S-oxirane analogue have the cis-configuration. Vibrational frequency and intrinsic reaction path calculations on a reduced size QM/MM model (2747 atoms

  3. Structure-property relationships in ABA copolymer gels with A homopolymer additions

    Science.gov (United States)

    Seitz, Michelle; Rottsolk, Rebecca; Page, Kirt; Shull, Kenneth

    2009-03-01

    ABA acrylic triblock copolymers with poly(methyl methacrylate) endblocks and poly(butyl acrylate) midblocks transition from free flowing liquids to elastic solids with decreasing temperature in alcohol solvents. Homopolymer PMMA chains can be solubilized in the micelle cores if they are shorter than the endblocks. Indentation and compression tests were used to determine gel's modulus and large strain behavior. Gels with volume fractions of PMMA less than ˜0.2 are highly elastic and have moduli dictated by stretching of bridging midblocks. At higher PMMA contents, gels exhibit greater permanent deformation and moduli over an order of magnitude larger than would be expected from rubber elasticity alone. Small angle X-ray and neutron scattering and mean field simulations were used to correlate changes in gel structure and micelle morphology with the addition of homopolymer.

  4. Bicontinuous Phases in Diblock Copolymer/Homopolymer Blends: Simulation and Self-Consistent Field Theory

    KAUST Repository

    Martínez-Veracoechea, Francisco J.

    2009-03-10

    A combination of particle-based simulations and self-consistent field theory (SCFT) is used to study the stabilization of multiple ordered bicontinuous phases in blends of a diblock copolymer (DBC) and a homopolymer. The double-diamond phase (DD) and plumber\\'s nightmare phase (P) were spontaneously formed in the range of homopolymer volume fraction simulated via coarse-grained molecular dynamics. To the best of our knowledge, this is the first time that such phases have been obtained in continuum-space molecular simulations of DBC systems. Though tentative phase boundaries were delineated via free-energy calculations, macrophase separation could not be satisfactorily assessed within the framework of particle-based simulations. Therefore, SCFT was used to explore the DBC/homopolymer phase diagram in more detail, showing that although in many cases two-phase coexistence of a DBC-rich phase and a homopolymer-rich phase does precede the stability of complex bicontinuous phases the DD phase can be stable in a relatively wide region of the phase diagram. Whereas the P phase was always metastable with respect to macrophase separation under the thermodynamic conditions explored with SCFT, it was sometimes nearly stable, suggesting that full stability could be achieved in other unexplored regions of parameter space. Moreover, even the predicted DD- and P-phase metastability regions were located significantly far from the spinodal line, suggesting that these phases could be observed in experiments as "long-lived" metastable phases under those conditions. This conjecture is also consistent with large-system molecular dynamics simulations that showed that the time scale of mesophase formation is much faster than that of macrophase separation. © 2009 American Chemical Society.

  5. Highly improved homopolymer aware nucleotide-protein alignments with 454 data

    Directory of Open Access Journals (Sweden)

    Lysholm Fredrik

    2012-09-01

    Full Text Available Abstract Background Roche 454 sequencing is the leading sequencing technology for producing long read high throughput sequence data. Unlike most methods where sequencing errors translate to base uncertainties, 454 sequencing inaccuracies create nucleotide gaps. These gaps are particularly troublesome for translated search tools such as BLASTx where they introduce frame-shifts and result in regions of decreased identity and/or terminated alignments, which affect further analysis. Results To address this issue, the Homopolymer Aware Cross Alignment Tool (HAXAT was developed. HAXAT uses a novel dynamic programming algorithm for solving the optimal local alignment between a 454 nucleotide and a protein sequence by allowing frame-shifts, guided by 454 flowpeak values. The algorithm is an efficient minimal extension of the Smith-Waterman-Gotoh algorithm that easily fits in into other tools. Experiments using HAXAT demonstrate, through the introduction of 454 specific frame-shift penalties, significantly increased accuracy of alignments spanning homopolymer sequence errors. The full effect of the new parameters introduced with this novel alignment model is explored. Experimental results evaluating homopolymer inaccuracy through alignments show a two to five-fold increase in Matthews Correlation Coefficient over previous algorithms, for 454-derived data. Conclusions This increased accuracy provided by HAXAT does not only result in improved homologue estimations, but also provides un-interrupted reading-frames, which greatly facilitate further analysis of protein space, for example phylogenetic analysis. The alignment tool is available at http://bioinfo.ifm.liu.se/454tools/haxat.

  6. Binary Mixed Homopolymer Brushes Tethered to Cellulose Nanocrystals: A Step Towards Compatibilized Polyester Blends.

    Science.gov (United States)

    Mincheva, Rosica; Jasmani, Latifah; Josse, Thomas; Paint, Yoann; Raquez, Jena-Marie; Gerbaux, Pascal; Eyley, Samuel; Thielemans, Wim; Dubois, Philippe

    2016-09-12

    This article reports on the successful preparation and characterization of cellulose nanocrystals (CNCs) surface-modified with polylactide (PLA) and poly(butylene succinate) (PBS) binary mixed homopolymer brushes. Their synthesis was designed as a three-step procedure combining polyester synthesis and surface-modification of CNCs with simultaneous polyester grafting via a heterogeneous copper(I)-catalyzed azide-alkyne cycloaddition reaction. For comparison, single homopolymer brushes tethered to CNCs (PLLA-g-CNC and PBSBDEMPAM-g-CNC) were obtained applying the same procedure. The hairy nanoparticles were characterized in terms of chemical composition and thermal properties. Spectroscopic analyses suggested "rippled" microphase separation of both immiscible homopolyesters in the mixed brushes, while others showed impeded homopolyester crystallization after surface-grafting. A synergistic relationship between the polyesters and CNCs was also suggested, i.e., the polyester grafting increases the CNC thermal resistance, while CNC presence imparts char formation. The as-obtained binary homopolymer brushes tethered to nanoparticles makes these surface-modified cellulosic nanomaterials attractive as compatibilization/reinforcement agents for PLA/PBS blends.

  7. Giardia cyst wall protein 1 is a lectin that binds to curled fibrils of the GalNAc homopolymer.

    Science.gov (United States)

    Chatterjee, Aparajita; Carpentieri, Andrea; Ratner, Daniel M; Bullitt, Esther; Costello, Catherine E; Robbins, Phillips W; Samuelson, John

    2010-08-19

    The infectious and diagnostic stage of Giardia lamblia (also known as G. intestinalis or G. duodenalis) is the cyst. The Giardia cyst wall contains fibrils of a unique beta-1,3-linked N-acetylgalactosamine (GalNAc) homopolymer and at least three cyst wall proteins (CWPs) composed of Leu-rich repeats (CWP(LRR)) and a C-terminal conserved Cys-rich region (CWP(CRR)). Our goals were to dissect the structure of the cyst wall and determine how it is disrupted during excystation. The intact Giardia cyst wall is thin (approximately 400 nm), easily fractured by sonication, and impermeable to small molecules. Curled fibrils of the GalNAc homopolymer are restricted to a narrow plane and are coated with linear arrays of oval-shaped protein complex. In contrast, cyst walls of Giardia treated with hot alkali to deproteinate fibrils of the GalNAc homopolymer are thick (approximately 1.2 microm), resistant to sonication, and permeable. The deproteinated GalNAc homopolymer, which forms a loose lattice of curled fibrils, is bound by native CWP1 and CWP2, as well as by maltose-binding protein (MBP)-fusions containing the full-length CWP1 or CWP1(LRR). In contrast, neither MBP alone nor MBP fused to CWP1(CRR) bind to the GalNAc homopolymer. Recombinant CWP1 binds to the GalNAc homopolymer within secretory vesicles of Giardia encysting in vitro. Fibrils of the GalNAc homopolymer are exposed during excystation or by treatment of heat-killed cysts with chymotrypsin, while deproteinated fibrils of the GalNAc homopolymer are degraded by extracts of Giardia cysts but not trophozoites. These results show the Leu-rich repeat domain of CWP1 is a lectin that binds to curled fibrils of the GalNAc homopolymer. During excystation, host and Giardia proteases appear to degrade bound CWPs, exposing fibrils of the GalNAc homopolymer that are digested by a stage-specific glycohydrolase.

  8. Giardia cyst wall protein 1 is a lectin that binds to curled fibrils of the GalNAc homopolymer.

    Directory of Open Access Journals (Sweden)

    Aparajita Chatterjee

    2010-08-01

    Full Text Available The infectious and diagnostic stage of Giardia lamblia (also known as G. intestinalis or G. duodenalis is the cyst. The Giardia cyst wall contains fibrils of a unique beta-1,3-linked N-acetylgalactosamine (GalNAc homopolymer and at least three cyst wall proteins (CWPs composed of Leu-rich repeats (CWP(LRR and a C-terminal conserved Cys-rich region (CWP(CRR. Our goals were to dissect the structure of the cyst wall and determine how it is disrupted during excystation. The intact Giardia cyst wall is thin (approximately 400 nm, easily fractured by sonication, and impermeable to small molecules. Curled fibrils of the GalNAc homopolymer are restricted to a narrow plane and are coated with linear arrays of oval-shaped protein complex. In contrast, cyst walls of Giardia treated with hot alkali to deproteinate fibrils of the GalNAc homopolymer are thick (approximately 1.2 microm, resistant to sonication, and permeable. The deproteinated GalNAc homopolymer, which forms a loose lattice of curled fibrils, is bound by native CWP1 and CWP2, as well as by maltose-binding protein (MBP-fusions containing the full-length CWP1 or CWP1(LRR. In contrast, neither MBP alone nor MBP fused to CWP1(CRR bind to the GalNAc homopolymer. Recombinant CWP1 binds to the GalNAc homopolymer within secretory vesicles of Giardia encysting in vitro. Fibrils of the GalNAc homopolymer are exposed during excystation or by treatment of heat-killed cysts with chymotrypsin, while deproteinated fibrils of the GalNAc homopolymer are degraded by extracts of Giardia cysts but not trophozoites. These results show the Leu-rich repeat domain of CWP1 is a lectin that binds to curled fibrils of the GalNAc homopolymer. During excystation, host and Giardia proteases appear to degrade bound CWPs, exposing fibrils of the GalNAc homopolymer that are digested by a stage-specific glycohydrolase.

  9. Sugar derivatives containing oxiranes and alpha,beta-unsaturated gamma-lactones as potential environmentally friendly insecticides.

    Science.gov (United States)

    Justino, Jorge; Rauter, Amélia P; Canda, Tana; Wilkins, Richard; Matthews, Elizabeth

    2005-10-01

    A range of novel sugar derivatives containing oxiranes or alpha,beta-unsaturated gamma-lactones in their structure were evaluated as potential insecticides with the added possible benefit of being benign in the environment. A number of arthropod species were chosen to represent those in the terrestrial, aerial and aquatic environments, covering target adult insects such as Musca domestica L (housefly) and Trialeurodes vaporariorum (Westwood) (glasshouse whitefly), which are public health and horticultural pests, Drosophila melanogaster Meig (fruitfly), both adult and larva, and a marine non-target crustacean, Artemia salina L. The tested compounds possessed efficacy and selectivity against these insect species, but were not toxic to brine shrimps, a reference organism in assays to evaluate the potential toxicity hazard to invertebrates in ecosystems.

  10. On the importance of vibrational contributions to small-angle optical rotation: Fluoro-oxirane in gas phase and solution

    Science.gov (United States)

    Pedersen, Thomas Bondo; Kongsted, Jacob; Crawford, T. Daniel; Ruud, Kenneth

    2009-01-01

    The specific optical rotation of (S)-fluoro-oxirane in gas phase and solution is predicted using time-dependent density functional theory (B3LYP functional) and coupled cluster linear response theory. Upon vibrational averaging, the coupled cluster singles and doubles model predicts the gas phase specific optical rotation to be 8.1° (dm g/cm3)-1 at 355 nm at room temperature. This is an order of magnitude smaller than the B3LYP result of 68.4° (dm g/cm3)-1. The main source of this discrepancy is the electronic contribution at the equilibrium geometry. The effects of cyclohexane and acetonitrile solvents are calculated for both the electronic and vibrational contributions with the B3LYP functional. The specific optical rotation is estimated to change significantly depending on the polarity of the solvent, increasing in cyclohexane and decreasing in acetonitrile.

  11. The effect of some homopolymers on the crystallization of calcium phosphates

    Science.gov (United States)

    García-Ramos, J. V.; Carmona, P.

    1982-04-01

    Homopolymer additives (poly-L-glutamic acid, poly-L-aspartic acid and polyglycine) were examined for their effects on the crystallization of hydroxyapatite (HA) and brushite. An accelerating effect of poly-L-glutamic acid on the precipitation of HA and brushite was discovered, whereas polyacrylic acid accelerates preferentially the HA precipitation. This accelerating efficiency is shown to be correlated with structural factors. The crystal habit of HA is modified by adsorption of poly-L-aspartic acid, this habit becoming similar to that of HA crystals from renal stones.

  12. A Wang-Landau study of the phase transitions in a flexible homopolymer

    Science.gov (United States)

    Seaton, D. T.; Wüst, T.; Landau, D. P.

    2009-04-01

    Using Wang-Landau sampling we study the characteristic behavior of a flexible homopolymer (off-lattice) for chain lengths up to N=300. The Hamiltonian consists of a Lennard-Jones potential between all monomers, and an additional FENE potential between bonded monomers. From the resultant density of states, we calculate thermodynamic properties for a wide range of temperatures, including low temperatures that are inaccessible to traditional Monte Carlo algorithms. Peaks in the specific heat and radius of gyration indicate the coil-globule and solid-liquid transitions. With a careful implementation of the algorithm, we find no evidence of a liquid-liquid transition.

  13. Phase Behavior of Diblock Copolymer–Homopolymer Ternary Blends: Congruent First-Order Lamellar–Disorder Transition

    Energy Technology Data Exchange (ETDEWEB)

    Hickey, Robert J.; Gillard, Timothy M.; Irwin, Matthew T.; Morse, David C.; Lodge, Timothy P.; Bates, Frank S. (UMM)

    2016-10-13

    We have established the existence of a line of congruent first-order lamellar-to-disorder (LAM–DIS) transitions when appropriate amounts of poly(cyclohexylethylene) (C) and poly(ethylene) (E) homopolymers are mixed with a corresponding compositionally symmetric CE diblock copolymer. The line of congruent transitions, or the congruent isopleth, terminates at the bicontinuous microemulsion (BμE) channel, and its trajectory appears to be influenced by the critical composition of the C/E binary homopolymer blend. Blends satisfying congruency undergo a direct LAM–DIS transition without passing through a two-phase region. We present complementary optical transmission, small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and dynamic mechanical spectroscopy (DMS) results that establish the phase behavior at constant copolymer volume fraction and varying C/E homopolymer volume ratios. Adjacent to the congruent composition at constant copolymer volume fraction, the lamellar and disordered phases are separated by two-phase coexistence windows, which converge, along with the line of congruent transitions, at an overall composition in the phase prism coincident with the BμE channel. Hexagonal and cubic (double gyroid) phases occur at higher diblock copolymer concentrations for asymmetric amounts of C and E homopolymers. These results establish a quantitative method for identifying the detailed phase behavior of ternary diblock copolymer–homopolymer blends, especially in the vicinity of the BμE.

  14. Methyl 2-methyl-4-(oxiran-2-ylmeth-oxy)-2H-1,2-benzothia-zine-3-carboxyl-ate 1,1-dioxide.

    Science.gov (United States)

    Ahmad, Matloob; Siddiqui, Hamid Latif; Zia-Ur-Rehman, Muhammad; Elsegood, Mark R J; Weaver, George W

    2010-01-09

    In the title compound, C(14)H(15)NO(6)S, the thia-zine ring adopts a distorted half-chair conformation. The structure displays several cooperative weak inter-molecular C-H⋯O hydrogen-bonding inter-actions, giving rise to a two-dimensional sheet packing motif. The CH(2) group in the meth-oxy linker to the oxirane ring, and the CH group in that ring, exhibit twofold positional disorder. The three-membered oxirane ring is twisted approximately perpendicular with respect to thia-zine ring (dihedral angle = 60/86° for the major/minor disorder components). 1,2-Benzothia-zines of this kind have a wide range of biological activities and are mainly used as medicines in the treatment of inflammation and rheumatoid arthritis.

  15. Properties of Low Surface Energy Fluorocarbon Polymers with Fluoro-acrylic Resins

    Institute of Scientific and Technical Information of China (English)

    LIU Xiusheng; WANG Can; LIU Lanxuan; LI Jian; GAO Wanzhen

    2008-01-01

    The low surface energy fluorocarbon polymer from the synthesized fluoro-acrylic resins was developed. Then the molecule orientation principle of nonpolar and polar functional groups in the polymers was analyzed. And the contact angles of pure water drops on the surfaces of various fluoro-monomer homopolymers and interpolymers were measured. So the relation of polymers' fluoro-content with the surface energy was determined. The distribution of fluoric functional groups in the polymers was investigated. And the test results show that though the total fluorine content of the fluorocarbon polymers is relative few, their surface energy is really low due to the enrichment of fluoro-chains on the polymers surface.

  16. The Plumber’s Nightmare Phase in Diblock Copolymer/Homopolymer Blends. A Self-Consistent Field Theory Study.

    KAUST Repository

    Martinez-Veracoechea, Francisco J.

    2009-11-24

    Using self-consistent field theory, the Plumber\\'s Nightmare and the double diamond phases are predicted to be stable in a finite region of phase diagrams for blends of AB diblock copolymer (DBC) and A-component homopolymer. To the best of our knowledge, this is the first time that the P phase has been predicted to be stable using self-consistent field theory. The stabilization is achieved by tuning the composition or conformational asymmetry of the DBC chain, and the architecture or length of the homopolymer. The basic features of the phase diagrams are the same in all cases studied, suggesting a general type of behavior for these systems. Finally, it is noted that the homopolymer length should be a convenient variable to stabilize bicontinuous phases in experiments. © 2009 American Chemical Society.

  17. Differentiation of Short Single-Stranded DNA Homopolymers in Solid-State Nanopores

    Science.gov (United States)

    Venta, Kimberly; Shemer, Gabriel; Puster, Matthew; Rodríguez-Manzo, Julio A.; Balan, Adrian; Rosenstein, Jacob K.; Shepard, Ken; Drndić, Marija

    2013-01-01

    In the last two decades, new techniques that monitor ionic current modulations as single molecules pass through a nanoscale pore have enabled numerous single-molecule studies. While biological nanopores have recently shown the ability to resolve single nucleotides within individual DNA molecules, similar developments with solid-state nanopores have lagged, due to challenges both in fabricating stable nanopores of similar dimensions as biological nanopores and in achieving sufficiently low-noise and high-bandwidth recordings. Here we show that small silicon nitride nanopores (0.8 to 2-nm-diameter in 5 to 8-nm-thick membranes) can resolve differences between ionic current signals produced by short (30 base) ssDNA homopolymers (poly(dA), poly(dC), poly(dT)), when combined with measurement electronics that allow a signal-to-noise ratio of better than 10 to be achieved at 1 MHz bandwidth. While identifying intramolecular DNA sequences with silicon nitride nanopores will require further improvements in nanopore sensitivity and noise levels, homopolymer differentiation represents an important milestone in the development of solid-state nanopores. PMID:23621759

  18. Vegetable oil-derived epoxy monomers and polymer blends: A comparative study with review

    Directory of Open Access Journals (Sweden)

    T. P. Schuman

    2013-03-01

    Full Text Available Glycidyl esters of epoxidized fatty acids derived from soybean oil (EGS and linseed oil (EGL have been synthesized to have higher oxirane content, more reactivity and lower viscosity than epoxidized soybean oil (ESO or epoxidized linseed oil (ELO. The EGS and ESO, for comparison, were used neat and in blends with diglycidyl ether of bisphenol A (DGEBA. Thermosetting resins were fabricated with the epoxy monomers and either BF3 catalyst or anhydride. The curing behaviors, glass transition temperatures, crosslink densities and mechanical properties were tested. The results indicated that polymer glass transition temperatures were mostly a function of oxirane content with additional influence of glycidyl versus internal oxirane reactivity, pendant chain content, and chemical structure and presence of saturated components. EGS provided better compatibility with DGEBA, improved intermolecular crosslinking and glass transition temperature, and yielded mechanically stronger polymerized materials than materials obtained using ESO. Other benefits of the EGS resin blend systems were significantly reduced viscosities compared to either DGEBA or ESO-blended DGEBA counterparts. Therefore, EGS that is derived from renewable sources has improved potential for fabrication of structural and structurally complex epoxy composites, e.g., by vacuum-assisted resin transfer molding.

  19. Hydrolysis of 4-Acetoxystyrene Polymers Prepared by Atom Transfer Radical Polymerization

    DEFF Research Database (Denmark)

    Chen, Xianyi; Jankova, Katja; Kops, Jørgen

    1999-01-01

    Hydrolysis of 4-acetoxystyrene polymers prepared by atom transfer radical polymerization was carried out under various reaction conditions. It was found that hydrazinolysis of 4-acetoxystyrene homopolymers, random and block copolymers with styrene in 1,4-dioxane, afforded the corresponding narrow...

  20. Homopolymer tail-mediated ligation PCR: a streamlined and highly efficient method for DNA cloning and library construction.

    Science.gov (United States)

    Lazinski, David W; Camilli, Andrew

    2013-01-01

    The amplification of DNA fragments, cloned between user-defined 5' and 3' end sequences, is a prerequisite step in the use of many current applications including massively parallel sequencing (MPS). Here we describe an improved method, called homopolymer tail-mediated ligation PCR (HTML-PCR), that requires very little starting template, minimal hands-on effort, is cost-effective, and is suited for use in high-throughput and robotic methodologies. HTML-PCR starts with the addition of homopolymer tails of controlled lengths to the 3' termini of a double-stranded genomic template. The homopolymer tails enable the annealing-assisted ligation of a hybrid oligonucleotide to the template's recessed 5' ends. The hybrid oligonucleotide has a user-defined sequence at its 5' end. This primer, together with a second primer composed of a longer region complementary to the homopolymer tail and fused to a second 5' user-defined sequence, are used in a PCR reaction to generate the final product. The user-defined sequences can be varied to enable compatibility with a wide variety of downstream applications. We demonstrate our new method by constructing MPS libraries starting from nanogram and sub-nanogram quantities of Vibrio cholerae and Streptococcus pneumoniae genomic DNA.

  1. Simulation of Vacuum UV Absorption and Electronic Circular Dichroism Spectra of Methyl Oxirane: the Role of Vibrational Effects

    Science.gov (United States)

    Hodecker, Manuel; Biczysko, Malgorzata; Dreuw, Andreas; Barone, Vincenzo

    2017-01-01

    Vibrationally resolved one-photon absorption and electronic circular dichroism spectra of (R)-methyl oxirane were calculated with different electronic and vibronic models selecting, through an analysis of the convergence of the results, the best compromise between reliability and computational cost. Linear-response TD-DFT/CAM-B3LYP/SNST electronic computations in conjunction with the simple vertical gradient vibronic model were chosen and employed for systematic comparison with the available experimental data. Remarkable agreement between simulated and experimental spectra was achieved for both one photon absorption and circular dichroism concerning peak positions, relative intensities, and general spectral shapes considering the computational efficiency of the chosen theoretical approach. The significant improvement of the results with respect to smearing of vertical electronic transitions by phenomenological Gaussian functions and the possible inclusion of solvent effects by polarizable continuum models at a negligible additional cost paves the route toward the simulation and analysis of spectral shapes of complex molecular systems in their natural environment. PMID:27159495

  2. Smart Homopolymer Microgels: Influence of the Monomer Structure on the Particle Properties

    Directory of Open Access Journals (Sweden)

    Bastian Wedel

    2016-04-01

    Full Text Available In this work, we compare the properties of smart homopolymer microgels based on N-n-propylacrylamide (NNPAM, N-isopropylacrylamide (NIPAM and N-isopropylmethacrylamide (NIPMAM synthesized under identical conditions. The particles are studied with respect to size, morphology, and swelling behavior using scanning electron and scanning force microscopy. In addition, light scattering techniques and fluorescent probes are employed to follow the swelling/de-swelling of the particles. Significant differences are found and discussed. Poly(N-n-propylacrylamide (PNNPAM microgels stand out due to their very sharp volume phase transition, whereas Poly(N-isopropylmethacrylamide (PNIPMAM particles are found to exhibit a more homogeneous network structure compared to the other two systems.

  3. Collapse transitions in a flexible homopolymer chain: application of the Wang-Landau algorithm.

    Science.gov (United States)

    Seaton, D T; Wüst, T; Landau, D P

    2010-01-01

    The thermodynamic behavior of a continuous homopolymer is described using the Wang-Landau algorithm for chain lengths up to N=561. The coil-globule and liquid-solid transitions are analyzed in detail with traditional thermodynamic and structural quantities. The behavior of the coil-globule transition is well within theoretical and computational predictions for all chain lengths, while the behavior of the liquid-solid transition is much more susceptible to finite-size effects. Certain "magic number" lengths (N=13,55,147,309,561) , whose minimal energy states offer unique icosahedral geometries, are discussed along with chains residing between these special cases. The low temperature behavior near the liquid-solid transition is rich in structural transformations for certain chain lengths, showing many similarities to the behavior of classical clusters with similar interaction potentials. General comments are made on this size dependent behavior and how it affects transition behavior in this model.

  4. Collapse transitions in a flexible homopolymer chain: Application of the Wang-Landau algorithm

    Science.gov (United States)

    Seaton, D. T.; Wüst, T.; Landau, D. P.

    2010-01-01

    The thermodynamic behavior of a continuous homopolymer is described using the Wang-Landau algorithm for chain lengths up to N=561 . The coil-globule and liquid-solid transitions are analyzed in detail with traditional thermodynamic and structural quantities. The behavior of the coil-globule transition is well within theoretical and computational predictions for all chain lengths, while the behavior of the liquid-solid transition is much more susceptible to finite-size effects. Certain “magic number” lengths (N=13,55,147,309,561) , whose minimal energy states offer unique icosahedral geometries, are discussed along with chains residing between these special cases. The low temperature behavior near the liquid-solid transition is rich in structural transformations for certain chain lengths, showing many similarities to the behavior of classical clusters with similar interaction potentials. General comments are made on this size dependent behavior and how it affects transition behavior in this model.

  5. Synthesis, characterization and dye removal ability of high capacity polymeric adsorbent: Polyaminoimide homopolymer

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoodi, Niyaz Mohammad, E-mail: nm_mahmoodi@aut.ac.ir [Department of Environmental Research, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of); Najafi, Farhood [Department of Resin and Additives, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of); Khorramfar, Shooka [Department of Environmental Research, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of); Textile Engineering Department, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Amini, Farrokhlegha [Department of Environmental Research, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of); Arami, Mokhtar [Textile Engineering Department, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2011-12-30

    Highlights: Black-Right-Pointing-Pointer Polyaminoimide homopolymer (PAIHP) was synthesized and characterized. Black-Right-Pointing-Pointer Kinetics data followed pseudo-second order kinetic model. Black-Right-Pointing-Pointer Isotherm data followed Langmuir isotherm. Black-Right-Pointing-Pointer Q{sub 0} for DR31, DR23, DB22 and AB25 was 6667, 5555, 9090 and 5882 mg/g, respectively. Black-Right-Pointing-Pointer PAIHP was regenerated at pH 12. - Abstract: In this paper, polyaminoimide homopolymer (PAIHP) was synthesized and its dye removal ability was investigated. Physical characteristics of PAIHP were studied using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). Direct Red 31 (DR31), Direct Red 23 (DR23), Direct Black 22 (DB22) and Acid Blue 25 (AB25) were used as model compounds. The kinetic and isotherm of dye adsorption were studied. The effect of operational parameter such as adsorbent dosage, pH and salt on dye removal was evaluated. Adsorption kinetic of dyes followed pseudo-second order kinetics. The maximum dye adsorption capacity (Q{sub 0}) of PAIHP was 6667 mg/g, 5555 mg/g, 9090 mg/g and 5882 mg/g for DR31, DR23, DB22 and AB25, respectively. It was found that adsorption of DR31, DR23, DB22 and AB25 onto PAIHP followed with Langmuir isotherm. Dye desorption tests (adsorbent regeneration) showed that the maximum dye release of 90% for DR31, 86% for DR23, 87% for DB22 and 90% for AB25 were achieved in aqueous solution at pH 12. The results showed that the PAIHP as a polymeric adsorbent with high dye adsorption capacity might be a suitable alternative to remove dyes from colored wastewater.

  6. Synthesis of Polymers Containing Covalently Bonded NLO Chromophores

    Science.gov (United States)

    Denga, Xiao-Hua; Sanghadasa, Mohan; Walton, Connie; Penn, Benjamin B.; Amai, Robert L. S.; Clark, Ronald D.

    1998-01-01

    Polymers containing covalently bonded nonlinear optical (NLO) chromophores are expected to possess special properties such as greater stability, better mechanical processing, and easier film formation than their non-polymeric equivalent. For the present work, polymethylmethacrylate (PMMA) was selected as the basic polymer unit on which to incorporate different NLO chromophores. The NLO components were variations of DIVA {[2-methoxyphenyl methylidene]-propanedinitrile} which we prepared from vanillin derivatives and malononitrile. These were esterified with methacrylic acid and polymerized either directly or with methyl methacrylate to form homopolymers or copolymers respectively. Characterization of the polymers and NLO property studies are underway.

  7. 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.

  8. In vivo behavior of trimethylene carbonate and epsilon-caprolactone-based (co)polymer networks : Degradation and tissue response

    NARCIS (Netherlands)

    Bat, Erhan; Plantinga, Josee A.; Harmsen, Martin C.; van Luyn, Marja J. A.; Feijen, Jan; Grijpma, Dirk W.

    2010-01-01

    The in vivo erosion behavior of crosslinked (co)polymers based on trimethylene carbonate (TMC) and epsilon-caprolactone (CL) was investigated. High molecular weight poly(trimethylene carbonate) (PTMC) homopolymer- and copolymer films were crosslinked by gamma irradiation. To adjust the in vivo

  9. SYNTHESIS AND PROPERTIES OF HOMOPOLYMER AND COPOLYMERS OBTAINED FROM 1-OCTADECENE WITH ZIRCONOCENE CATALYSTS

    Institute of Scientific and Technical Information of China (English)

    Raúl Quijada; Juan L.Guevara; Rene Rojas; Franco M.Rabagliati

    2000-01-01

    Studies related to the behavior of different metallocene catalysts for the homopolymerization of 1-octadecene and its copolymerization with ethylene will be presented. The metallocenes: rac-Et(Ind)2ZrCl2, rac-Me2Si(Ind)2ZrCl2 and Ph2C(Flu)(Cp)ZrCl2 were chosen for the homopolymerization study. They show important differences in catalytic activity at high temperatures (≥70 ℃), with rac-Et(Ind)2ZrCl2 showing the highest activity. At lower temperatures (≤30 ℃) the differences are negligible. For the copolymerization of ethylene with 1-octadecene only the catalysts rac-Et(Ind)2ZrCl2 and rac-Me2Si(Ind)2ZrCl2 were studied. The results show that their catalytic activity is just like that for the homopolymerization of l-octadecene, with higher activity for the metallocene with the Et-bridged catalyst. 13C-NMR analysis shows that the composition of the copolymerization products depends on the catalytic systems. Copolymers obtained with racMe2Si(Ind)2ZrCl2 have greater comonomer incorporation. Thermal analysis shows that poly-1-octadecene synthesized with the catalyst rac-Et(Ind)2ZrCl2 is very dependent on the polymerization temperature. The homopolymer obtained at 70℃presents two endothermal peaks at 41 ℃ and 53 ℃, as compared with the one obtained at 30 ℃ which presents one wider peak with a maximum at 67℃. For the catalyst rac-Me2Si(Ind)2ZrCl2 this trend is not observed. The type of metallocene and the reaction time do not significantly change the intrinsic viscosity, but the polymerization temperature changes it drastically,giving higher values at lower temperature. Viscosity measurements on the copolymers show that an increase of comonomer concentration in the feed reduces the molecular weight of the copolymer, and it was also found that for homopolymer, the molecular weight is independent of the catalytic systems.

  10. Chemo-Enzymatic Synthesis of Chiral Epoxides Ethyl and Methyl (S-3-(Oxiran-2-ylpropanoates from Renewable Levoglucosenone: An Access to Enantiopure (S-Dairy Lactone

    Directory of Open Access Journals (Sweden)

    Aurélien A. M. Peru

    2016-07-01

    Full Text Available Chiral epoxides—such as ethyl and methyl (S-3-(oxiran-2-ylpropanoates ((S-1a/1b—are valuable precursors in many chemical syntheses. Until recently, these compounds were synthesized from glutamic acid in four steps (deamination, reduction, tosylation and epoxide formation in low to moderate overall yield (20%–50%. Moreover, this procedure requires some harmful reagents such as sodium nitrite ((ecotoxic and borane (carcinogen. Herein, starting from levoglucosenone (LGO, a biobased chiral compound obtained through the flash pyrolysis of acidified cellulose, we propose a safer and more sustainable chemo-enzymatic synthetic pathway involving lipase-mediated Baeyer-Villiger oxidation, palladium-catalyzed hydrogenation, tosylation and treatment with sodium ethoxide/methoxide as key steps. This route afforded ethyl and methyl (S-3-(oxiran-2-ylpropanoates in 57% overall yield, respectively. To demonstrate the potentiality of this new synthetic pathway from LGO, the synthesis of high value-added (S-dairy lactone was undertaken from these epoxides and provided the target in 37% overall yield from LGO.

  11. Restrictions in Model Reduction for Polymer Chain Models in Dissipative Particle Dynamics

    KAUST Repository

    Moreno Chaparro, Nicolas

    2014-06-06

    We model high molecular weight homopolymers in semidilute concentration via Dissipative Particle Dynamics (DPD). We show that in model reduction methodologies for polymers it is not enough to preserve system properties (i.e., density ρ, pressure p, temperature T, radial distribution function g(r)) but preserving also the characteristic shape and length scale of the polymer chain model is necessary. In this work we apply a DPD-model-reduction methodology for linear polymers recently proposed; and demonstrate why the applicability of this methodology is limited upto certain maximum polymer length, and not suitable for solvent coarse graining.

  12. SYNTHESIS AND CHARACTERIZATION OF COMB-LIKE POLYMERS BEARING HETEROCYCLIC AZO GROUP AND MESOGENIC GROUP

    Institute of Scientific and Technical Information of China (English)

    Hui-qi Zhang; Wen-qiang Huang; Chen-xi Li; Bing-lin He

    1999-01-01

    The synthesis and characterization of a series of novel comb-like polymethacrylates bearing heterocyclic azo group and mesogenic group are described. The thermal properties of the polymers such as thermal stability and phase transition behavior were investigated by thermogravimetric analysis, differential thermal analysis and polarizing optical microscopy techniques. The experimental results show that all the synthesized polymers do not exhibit liquid crystallinity except the homopolymer of the mesogenic monomer MAPB2 and the glass transition temperatures of the polymers increase with increasing content of azo moiety in polymers linearly.

  13. A diethyl phosphonate containing oxazoline: Synthesis and characterization of monomer and homopolymer

    Energy Technology Data Exchange (ETDEWEB)

    Hermes, R.E.; Thompson, R.D.; Valdez, L.S.

    1995-05-01

    A diethyl phosphonate oxazoline monomer and its polymer have been synthesized. The monomer appears to polymerize via a ring-opening mechanism giving the expected polyethyleneimine backbone with pendant carbonyl groups. Two distinct molecular weights were produced during polymerization suggesting two mechanisms of chain growth. Studies are underway to elucidate the reasons for this. This polymer has potential as a metal-chelating agent.

  14. Self-Consistent Field Theory for the Design of Thermoplastic Elastomers from Miktoarm Block Copolymer - Homopolymer Blends

    Science.gov (United States)

    Hamilton, Andrew Lawrence

    We have used self-consistent field theory to study the morphological characteristics of blends of miktoarm block copolymers and homopolymers. More specifically, we have studied the effects of segregation strength, miktoarm block copolymer composition, and homopolymer size and volume fraction on the phase diagrams of these systems. A15 domains with discrete A-monomer spherical domains were found to be stable with A-monomer loading fractions of at least as high as 52%. Hexagonally-packed cylindrical domains were found to be stable at A-monomer loadings of at least as high as 72%. These findings represent a significant improvement from the loading fractions of 43% and 60% reported by Lynd et al. for spherical and cylindrical domains in neat miktoarm block copolymers, respectively. It is also quite possible that even greater loading fractions are achievable in systems too large for our simulations. These results predict exciting new materials for next-generation thermoplastic elastomers, since the ideal TPE has a large loading of A monomers in discrete, crystalline or glassy domains, surrounded by a continuous matrix of elastomeric B domains. Additionally, we have performed SCFT simulations modelled after experimental blends of polystyrene and polyisoprene-based miktoarm block copolymers and homopolymers. Certain experimental samples showed fascinating new "bricks and mortar" phases and swollen asymmetric lamellar phases. In both cases, the A domains are highly swollen with homopolymer, forcing the miktoarm block copolymer to segregate near the interface and adopt the role of a surfactant. The resulting structures maintain separate A and B domains, but lack long-range order. While it is not possible to study these mesophases using SCFT, since they lack long-range order and therefore well-defined symmetry, our SCFT results show the onset of macrophase separation at similar homopolymer loadings, for both the bricks and mortar phases and the highly swollen lamellae. This

  15. Statistical conjugated polymers comprising optoelectronically distinct units.

    Science.gov (United States)

    Hollinger, Jon; Sun, Jing; Gao, Dong; Karl, Dominik; Seferos, Dwight S

    2013-03-12

    Poly(3-heptylselenophene)-stat-poly(3-hexylthiophene) is synthesized and characterized in terms of its crystallinity and performance in an organic photovoltaic (OPV) cell. Despite the random distribution of units along the polymer main chain, the material is semi-crystalline, as demonstrated by differential scanning calorimetry and wide-angle X-ray diffraction. Thin-film absorption suggests an increased compatibility than seen with 3-hexylselenophene monomer. Optoelectronic properties are an average of the two homopolymers, and OPV performance is enhanced by a broadened absorption profile and a favorable morphology.

  16. An adaptive bin framework search method for a beta-sheet protein homopolymer model

    Directory of Open Access Journals (Sweden)

    Hoos Holger H

    2007-04-01

    Full Text Available Abstract Background The problem of protein structure prediction consists of predicting the functional or native structure of a protein given its linear sequence of amino acids. This problem has played a prominent role in the fields of biomolecular physics and algorithm design for over 50 years. Additionally, its importance increases continually as a result of an exponential growth over time in the number of known protein sequences in contrast to a linear increase in the number of determined structures. Our work focuses on the problem of searching an exponentially large space of possible conformations as efficiently as possible, with the goal of finding a global optimum with respect to a given energy function. This problem plays an important role in the analysis of systems with complex search landscapes, and particularly in the context of ab initio protein structure prediction. Results In this work, we introduce a novel approach for solving this conformation search problem based on the use of a bin framework for adaptively storing and retrieving promising locally optimal solutions. Our approach provides a rich and general framework within which a broad range of adaptive or reactive search strategies can be realized. Here, we introduce adaptive mechanisms for choosing which conformations should be stored, based on the set of conformations already stored in memory, and for biasing choices when retrieving conformations from memory in order to overcome search stagnation. Conclusion We show that our bin framework combined with a widely used optimization method, Monte Carlo search, achieves significantly better performance than state-of-the-art generalized ensemble methods for a well-known protein-like homopolymer model on the face-centered cubic lattice.

  17. Preparation and Unimolecular-Micellization Behavior of Homopolymer of Surface-Active Monomer AMC14AB

    Institute of Scientific and Technical Information of China (English)

    Kang-kai Liu; Lei Li

    2008-01-01

    (2-acrylamido) ethyl tetradecyl dimethylammonium bromide (AMC14AB) was polymerized in aqueous solution to form the homopolymer P(AMC14AB). The physicochemical properties of P(AMC14AB) in aqueous solution were mainly studied with fluorescent probe method, surface tension measurement and conductometry. The experimental results show that the aggregation morphology of P(AMC14AB) in aqueous solution is unimolecular micelle as expected. Being different from conventional multimolecular micelle systems, the unimoleculax micelle system of P(AMC14AB) not only shows critical micellar concentration (CMC=0), (i.e.once added to pure water, the surface tension decreases immediately in spite how small the density is), but also the surface tension stays almost the same with the concentration increasing. That is to say, there is no mutational point on the relationship curve between surface tension and concentration. Furthermore, the unimolecular micelle system of P(AMC14AB) has no Krafft temperature, i.e. at any temperature, so long as it is dissolved in water, the unimolecular micelles will form. Besides this, for the solubilization of hydrophobic organic substances, the unimolecular micelle system of P(AMC14AB) is obviously different from the common multimolecular micelle system, having no turning point on the relationship curve between toluene solubilizaion amount and P(AMC14AB) concentration, and the solubilizing ability of the unimolecular-micelle system of P(AMC14AB) for hydrophobic organic substances is much higher than that of the conventional multimolecular micelle solutions of common surfactants, such as centyl trimethyl ammonium bromide.

  18. Polymers and block copolymers of fluorostyrenes by ATRP

    DEFF Research Database (Denmark)

    Hvilsted, Søren; Borkar, Sachin; Abildgaard, Lillian;

    2002-01-01

    Fully or partly fluorinated polymers have many desirable and intriguing properties. In the framework of a larger program on design and control of new functional block copolymers we recently employed the Atom Transfer Radical Polymerization (ATRP) protocol on 2,3,4,5,6-pentafluorostyrene (FS). We...... materials based on 2,3,5,6-tetrafiuoro-4-methoxy-styrene (TFMS). TFMS homopolymers as well as diblock copolymers with FS are produced by ATRP. Both types of novel polymers were subsequently demethylated and different side chains introduced on the resulting hydroxy sites....

  19. High temperature lithium cells with solid polymer electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jin; Eitouni, Hany Basam; Singh, Mohit

    2017-03-07

    Electrochemical cells that use electrolytes made from new polymer compositions based on poly(2,6-dimethyl-1,4-phenylene oxide) and other high-softening-temperature polymers are disclosed. These materials have a microphase domain structure that has an ionically-conductive phase and a phase with good mechanical strength and a high softening temperature. In one arrangement, the structural block has a softening temperature of about 210.degree. C. These materials can be made with either homopolymers or with block copolymers. Such electrochemical cells can operate safely at higher temperatures than have been possible before, especially in lithium cells. The ionic conductivity of the electrolytes increases with increasing temperature.

  20. Nanostructure investigation of polymer solutions, polymer gels, and polymer thin films

    Science.gov (United States)

    Lee, Wonjoo

    surfactants in polymer solutions and the corresponding hydrogels using small angle neutron scattering (SANS). SANS has been widely used to investigate structures ranging from sub-nanometer to sub-micrometer. Since the scattering lengths of H and D atoms are quite different, the scattering contrast can be enhanced (and varied) through isotopic labeling. It is possible to investigate the structure of micelles in polymer solutions and hydrogels using H/D contrast matching methods with SANS. For this aim, water-soluble and chemically crosslinkgable poly((2-dimethylamino)ethyl methacrylate) (PDMAEMA) was synthesized using group transfer polymerization. In order to control the size and shape of micelles, the degree of quaternization of the polymer was also controlled through the reaction of PDMAEMA with methyl iodide. The micellization of deuterated sodium dodecylsulfate (d-SDS) in (quaternized) PDMAEMA solutions and the corresponding hydrogels was then observed using SANS and the size and shape of d-SDS micelles was obtained by modeling. 2. Nanopatterning using block copolymer/homopolymer blends. Block copolymers are well-known to self-assemble into meso- and nano-scale structures. The use of block copolymers for nanostructured patterns has attracted increasing attention due to their potential use as templates and scaffolds for the fabrication of functional nanostructures. In order to realize the potential of these materials, it is necessary to be able to control the orientation of the nanoscale pattern in a precise manner. Numerous methods such as manipulation of the interfacial surface energies, use of electric fields, and controlling the rate of solvent evaporation have developed to control orientation. In addition, it has been shown that nanopores within cylindrical domains oriented normal to the substrate can be generated by several methods. For example, one component can be degraded by UV exposure, or the homopolymer in a block copolymer/homopolymer blend can be extracted in

  1. Fabrication of robust (bio)interfaces based on reactive polymer films : surface confinement, reactivity and pattern fabrication on multiple length scales

    NARCIS (Netherlands)

    Feng, Chuan Liang

    2005-01-01

    The aim of the work described in this Thesis was to investigate interfacial reactions in confinement on ultrathin homopolymer and diblock copolymer films, the immobilization of (bio)molecules and the fabrication of biomolecular patterns by reactive microcontact printing (µCP) on these reactive polym

  2. Using theory and simulation to link molecular features of nanoscale fillers to morphology in polymer nanocomposites

    Science.gov (United States)

    Jayaraman, Arthi; Martin, Tyler

    2014-03-01

    Polymer nanocomposites are a class of materials that consist of a polymer matrix embedded with nanoscale fillers or additives that enhance the inherent properties of the matrix polymer. To engineer polymer nanocomposites for specific applications with target macroscopic properties (e.g. photovoltaics, photonics, automobile parts) it is important to have design rules that relate molecular features to equilibrium morphology of the composite. In the first part of the talk I will present our recent theory and simulation work on composites containing polymer grafted nanoparticles, showing how polydispersity in graft and matrix polymers (physical heterogeneity) can be used to stabilize dispersion of the nanoparticles within a polymer matrix. In the second part of the talk I will present our recent work linking block-copolymer functionalization to the nanoparticle location in a polymer matrix consisting of homopolymer blends.

  3. 非对称环氧乙烷的区域选择性亲核开环反应%Regioselective Nucleophilic Ring Opening Reactions of Unsymmetric Oxiranes

    Institute of Scientific and Technical Information of China (English)

    周婵; 许家喜

    2011-01-01

    本文总结了常用亲核试剂对非对称环氧乙烷的亲核开环反应及其区域选择性.强亲核性的亲核试剂通常只受空间效应影响,进攻非对称环氧乙烷位阻小的碳原子,对于烯基取代环氧乙烷还可以进攻烯基的β-碳原子发生Sn2'开环反应,其他亲核试剂同时受空间效应和电子效应的影响,对于烷基环氧乙烷通常进攻其取代少的碳原子,空间效应起主导作用,而对芳基和烯基取代环氧乙烷开环反应通常发生在环氧乙烷芳甲位和烯丙位的碳原子上,电子效应起主导作用.在质子酸或强Lewis酸存在下,虽然单烷基环氧乙烷的开环仍然发生在其取代少的碳原子上,但对于芳基、烯基和同碳双取代环氧乙烷,亲核开环反应将主要受电子效应控制,一般亲核试剂倾向于进攻环氧乙烷的芳甲位、烯丙位或多取代的碳原子.分子内的亲核开环反应主要受成环时环大小的控制,成环时的倾向是五元环>六元环>七元环.环氧乙烷亲核开环的区域选择性是环氧乙烷和亲核试剂空间效应和电子效应平衡的结果.%Nucleophilic ring opening reactions of unsymmetric oxiranes and their regioselectivity with widely used nucleophiles are reviewed. Strong nucleophiles attack the less substituted carbon atom of unsymmetric oxiranes, whatever alkyl, alkenyl, and aryloxiranes, controlled by the steric hindrance only. They can undergo an SN2' ring-opening reaction with alkenyloxiranes via the attack on the β-carbon atom of their alkenyl group. Other nucleophiles generally attack the less substituted carbon atom for alkyloxiranes, controlled by the steric hindrance,but attack the arylmethyl and allyl carbon atom for aryl and alkenyloxiranes, controlled by the electronic effect. In the presence of proton acids or strong Lewis acids, although monoalkyloxiranes are attacked on their less substituted carbon atom with nucleophiles (steric hindrance control), aryl, alkenyl

  4. Assessment of the relevance of the antibiotic 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine from Pantoea agglomerans biological control strains against bacterial plant pathogens

    Science.gov (United States)

    Sammer, Ulrike F; Reiher, Katharina; Spiteller, Dieter; Wensing, Annette; Völksch, Beate

    2012-01-01

    The epiphyte Pantoea agglomerans 48b/90 (Pa48b) is a promising biocontrol strain against economically important bacterial pathogens such as Erwinia amylovora. Strain Pa48b produces the broad-spectrum antibiotic 2-amino-3-(oxirane-2,3-dicarboxamido)-propanoyl-valine (APV) in a temperature-dependent manner. An APV-negative mutant still suppressed the E. amylovora population and fire blight disease symptoms in apple blossom experiments under greenhouse conditions, but was inferior to the Pa48b wild-type indicating the influence of APV in the antagonism. In plant experiments with the soybean pathogen Pseudomonas syringae pv. glycinea both, Pa48b and the APV-negative mutant, successfully suppressed the pathogen. Our results demonstrate that the P. agglomerans strain Pa48b is an efficient biocontrol organism against plant pathogens, and we prove its ability for fast colonization of plant surfaces over a wide temperature range. PMID:23233458

  5. GRAFT POLYMERIZATION OF ACRYLAMIDE ONTO HOMOPOLYMER OF 5-METHYL-5-HEXEN-2, 4-DIONE INITIATED BY CERIC ION

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jingbo; ZHAO Tong; QIU Kunyuan

    1997-01-01

    The homopolymerization of 5-methyl-5-hexen-2,4-dione (methacryloylacetone, MAA),a vinyl monomer having β-diketone group, was carried out in the presence of benzophenone (BP)/N, N-dimenthyl-4-toluidine (DMT) system. Graft polymerization of acrylamide initiated by ceric ion onto the homopolymer film was investigated and the mechanism of the grafting reaction was proposed on the basis of ESR study. The grafted copolymer was characterized by means of grafting percentage, water absorption, XPS spectra and scanning electron photomicrographs.

  6. Ionic conductivity of mesoporous block copolymer membranes in liquid electrolyte as a function of copolymer and homopolymer molecular weight

    Science.gov (United States)

    Wong, David; Mullin, Scott; Stone, Greg; Battaglia, Vincent; Balsara, Nitash

    2011-03-01

    Mesoporous block copolymer membranes have been synthesized using poly(styrene-block-ethylene-block-polystyrene) (SES). A series of symmetric SES copolymers and PS homopolymers have been studied at different blending fractions. Ionic conductivities of the porous films in a liquid electrolyte, 1.0 M Li PF6 in ethylene carbonate/diethyl carbonate, compare favorably to conventional battery separators and generally increase with internal surface area, as measured by nitrogen adsorption. Characterization of the effects of pore structure and SES morphology on conductivity will be presented. Support from the U.S. Department of Energy Office of Vehicles Technologies (FCVT) under the Batteries for Advanced Transportation Technologies (BATT) Program.

  7. The hyphal wall of Mucor mucedo. 2. Hexosamine-containing polymers.

    Science.gov (United States)

    Datema, R; Wessels, J G; van den Ende, H

    1977-11-01

    Nitrous acid, which specifically depolymerises polymers containing hexosamines with a primary amino group, was used to analyse the hexosamine-containing polymers in the hyphal wall of Mucor mucedo. N-Acetylglucosamine was found to occur in three polymeric fractions. One fraction which was solubilised by HNO2 treatment contained-N-acetylglucosamine interspersed with glucosamine; no homopolymer of glucosamine (chitosan) was detected. Another fraction became HNO2-soluble after treatment with pronase or alkali; this points to the occurrence of a heteropolymer containing N-acetylglucosamine and glucosamine in which some of the glucosamine residues are linked to peptides via their amino groups. The residue remaaining after pronase and HNO* treatment appeared to consist of a homopolymer of N-acetylglucosamine (chitin).

  8. Syntheses and studies of acetylenic polymers

    Energy Technology Data Exchange (ETDEWEB)

    Yiwei, Ding

    1994-03-03

    Based on new diiodo aryl compounds a series of novel soluble polymers, poly(2,5-dialkoxy-1,4-phenyleneethynylene)s (PPE polymers) were synthesized using palladium-catalysis. The molecular weights (MW) range from 8,000 to 40,000. Properties such as absorption, fluorescence, and conductivity were studied. A PPE polymer with butoxy side chain exhibits a weak electrical conductivity ({sigma} = 10{sup {minus}3} S/cm) after doping with AsF{sub 5}. Absorption spectra in THF solution at room temperature (RT) show a maximum at 440 nm. However, absorption spectra of PPE polymers in the film state at (RT) show a maximum at 480 nm. PPE polymer-based light emitting diode (LED) devices have been prepared; greenish light from these LED devices can be observed. Poly(ethynylene-p-arylene-ethynylene-silylene)s were synthesized through the same palladium-catalyzed polymerization; MWs are between 6,000 and 82,000. Absorption and fluorescence were studied. Some of these polymers exhibit thermotropic liquid crystalline properties. In addition, nonlinear optical properties were briefly examined. Poly(silylene-ethynylene) homopolymers as well as alternating copolymers were synthesized through a novel palladium-catalyzed polymerization; MWs range from 56 {times} 10{sup 3} to 5.3 {times} 10{sup 3}. Thermal stability of these was also investigated; char yields range from 56 to 83%. One of these polymers exhibits thermotropic liquid crystalline properties.

  9. Syntheses and studies of acetylenic polymers

    Energy Technology Data Exchange (ETDEWEB)

    Yiwei, Ding [Iowa State Univ., Ames, IA (United States)

    1994-03-03

    Based on new diiodo aryl compounds a series of novel soluble polymers, poly(2,5-dialkoxy-1,4-phenyleneethynylene)s (PPE polymers) were synthesized using palladium-catalysis. The molecular weights (MW) range from 8,000 to 40,000. Properties such as absorption, fluorescence, and conductivity were studied. A PPE polymer with butoxy side chain exhibits a weak electrical conductivity (σ = 10-3 S/cm) after doping with AsF5. Absorption spectra in THF solution at room temperature (RT) show a maximum at 440 nm. However, absorption spectra of PPE polymers in the film state at (RT) show a maximum at 480 nm. PPE polymer-based light emitting diode (LED) devices have been prepared; greenish light from these LED devices can be observed. Poly(ethynylene-p-arylene-ethynylene-silylene)s were synthesized through the same palladium-catalyzed polymerization; MWs are between 6,000 and 82,000. Absorption and fluorescence were studied. Some of these polymers exhibit thermotropic liquid crystalline properties. In addition, nonlinear optical properties were briefly examined. Poly(silylene-ethynylene) homopolymers as well as alternating copolymers were synthesized through a novel palladium-catalyzed polymerization; MWs range from 56 x 103 to 5.3 x 103. Thermal stability of these was also investigated; char yields range from 56 to 83%. One of these polymers exhibits thermotropic liquid crystalline properties.

  10. Morphology control in thin films of PS:PLA homopolymer blends by dip-coating deposition

    Science.gov (United States)

    Vital, Alexane; Vayer, Marylène; Tillocher, Thomas; Dussart, Rémi; Boufnichel, Mohamed; Sinturel, Christophe

    2017-01-01

    In this work, smooth polymer films of PS, PLA and their blends, with thicknesses ranging from 20 nm up to 400 nm and very few defects on the surface were obtained by dip-coating. In contrast to the process of spin-coating which is conventionally used to prepare thin films of polymer blends, we showed that depending on the deposition parameters (withdrawal speed and geometry of the reservoir), various morphologies such as layered films and laterally phase-separated domains could be formed for a given blend/solvent pair, offering much more opportunities compared to the spin-coating process. This diversity of morphologies was explained by considering the superposition of different phenomena such as phase separation process, dewetting and vitrification in which parameters such as the drying time, the compatibility of the polymer/solvent pairs and the affinity of the polymer towards the interfaces were suspected to play a significant role. For that purpose, the process of dip-coating was examined within the capillary and the draining regimes (for low and high withdrawal speed respectively) in order to get a full description of the thickness variation and evaporation rate as a function of the deposition parameters.

  11. Compatibilizing Effect of Random or Block Copolymer Added to Binary Mixture of Homopolymers.

    Science.gov (United States)

    2014-09-26

    copolymer R50/50 (Mw 25000); filled squares: random copolymer RF50/50 (M 16300); filled diamonds : random copolymer SPP45 (Mw > 2.3 x 105); open squares...Pennsylvania 18015 Dr. R. S. Porter Professor Brian Newman Department of Polymer Science Department of Mechanics and and Engineering Materials Science

  12. Theoretically informed entangled polymer simulations: linear and non-linear rheology of melts

    OpenAIRE

    Ramírez-Hernández, Abelardo; MÜLLER, Marcus; de Pablo, Juan J.

    2013-01-01

    In recent years, there has been a resurgence in developing models and theories for the non-equilibrium behavior of polymeric liquids. The so-called “tube” models, gradually refined over decades of research, can now provide a description of the linear and non-linear rheology of entangled polymers that is qualitatively consistent with experiments. Such approaches, however, have been limited to homopolymers. Here we present a general formalism that relies on the concept of slip links...

  13. Synthesis of dye linked conducting block copolymers, dye linked conducting homopolymers and preliminary application to photovoltaics

    DEFF Research Database (Denmark)

    Krebs, Frederik C; Hagemann, O.; Jørgensen, M.

    2004-01-01

    A synthetic approach to the synthesis of a large super molecule composed of two chemically different conducting polymer blocks with, respectively, high and low lying electronic energy levels linked through a porphyrin dye molecule is presented. The synthetic strategies to these molecular...... architectures are discussed. Finally the molecular systems are applied to make photovoltaic devices and the rather low efficiency is discussed in terms of the synthetic approach. (C) 2004 Elsevier B.V. All rights reserved....

  14. Molecular dynamics simulations of linear and cyclic amphiphilic polymers in aqueous and organic environments.

    Science.gov (United States)

    Liu, Lixin; Parameswaran, Sreeja; Sharma, Arjun; Grayson, Scott M; Ashbaugh, Henry S; Rick, Steven W

    2014-06-19

    We have studied the conformational changes of two novel amphiphilic homopolymers in water and toluene relevant to delivery applications using molecular dynamics simulations supplemented with enhanced sampling techniques. The individual homopolymer repeating units are amphiphilic with a hydrophobic dodecyl chain and a hydrophilic tetra(ethylene glycol) chain attached via ether linkages to each repeating unit of the polymer backbone. Two polymer topologies were examined: one cyclic and one an exact linear analog. Here we show that these polymers exhibit highly dynamic conformations with the side arm orientations driven by the solvent polarity. In water these polymers exhibit a compact conformation with the hydrophobic arms retracted toward the backbone core, whereas in toluene the hydrophobic arms extended into the solvent. Different from the hydrophobic arms, the hydrophilic ethylene glycol chain orientations and backbone conformations are largely unperturbed by the solvent polarity. Probing the polymer microenvironment in different solvents to examine solute uptake supports the hypothesis that these polymers can selectively encapsulate/release guest molecules depending on the solvent polarity, highlighting the potential of these polymers as drug delivery vehicles.

  15. Partition function zeros of a square-lattice homopolymer with nearest- and next-nearest-neighbor interactions.

    Science.gov (United States)

    Lee, Jae Hwan; Kim, Seung-Yeon; Lee, Julian

    2013-05-01

    We study distributions of the partition function zeros in the complex temperature plane for a square-lattice homopolymer with nearest-neighbor (NN) and next-nearest-neighbor (NNN) interactions. The dependence of distributions on the ratio of NN and NNN interaction strengths R is examined. The finite-size scaling of the zeros is performed to obtain the crossover exponent, which is shown to be independent of R within error bars, suggesting that all of these models belong to the same universality class. The transition temperatures are also computed by the zeros to obtain the phase diagram, and the results confirm that the model with stronger NNN interaction exhibits stronger effects of cooperativity.

  16. Neutron scattering characterization of homopolymers and graft-copolymer micelles in supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Chillura-Martino, D; Triolo, R. [Palermo Univ. (Italy). Ist. di Chimica Fisica; McClain, J.B. [North Carolina Univ., Chapel Hill, NC (United States)] [and others

    1995-12-31

    Supercritical fluids are becoming an attractive alternative to the liquid solvents traditionally used as polymerization media. As the synthesis proceeds, a wide range of colloidal aggregates form, but there has hitherto been no way to measure such structures directly. We have applied small-angle neutron scattering (SANS) to characterize such systems, and although SCF polymerizations are carried out at high pressures, the penetrating power of the neutron beam means that typical cell windows are virtually transparent. Systems studied include molecules soluble in CO{sub 2} (e.g. polyfluoro-octyl acrylate or PFOA) and this polymer has previously been shown to exhibit a positive second virial coefficient (A{sub 2}). Other CO{sub 2}-soluble polymers include hexafluoro-polypropylene oxide (HFPPO), which appears to have a second virial coefficient which is close to zero (10{sup 4}A{sub 2} {approx_equal} 0 +{+-} 0.2 cm{sup 3} g{sup -2} mol). Polydimethylsiloxane (PDMS), is soluble on the molecular level only in the limit of dilute solution and seems to form aggregates as the concentration increases (c > 0.01 g cm{sup -3}). Other polymers (e.g. polystyrene) are insoluble in CO{sub 2}, though polymerizations may be accomplished via the use of PS-PFOA blockcopolymer stabilizers, which are also amenable to SANS characterization, and have been shown to form micelles in CO{sub 2}. Other amphiphilic surfactant molecules that form micelles include PFOA-polyethylene oxide (PFOA-PEO) graft copolymers, which swell as the CO{sub 2} medium is saturated with water. These systems have been characterized by SANS, by taking advantage of the different contrast options afforded by substituting D{sub 2}O for H{sub 2}O. This paper illustrates the utility of SANS to measure molecular dimensions, thermodynamic variables, molecular weights, micelle structures etc. in supercritical CO{sub 2}.

  17. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  18. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2008-12-30

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  19. Ferritin nanocontainers that self-direct in synthetic polymer systems

    Science.gov (United States)

    Sengonul, Merih C.

    Currently, there are many approaches to introduce functionality into synthetic polymers. Among these, for example, are copolymerization, grafting, and blending methods. However, modifications made by such methods also change the thermodynamics and rheological properties of the polymer system of interest, and each new modification often requires a costly reoptimization of polymer processing. Such a reoptimalization would not be necessary if new functionality could be introduced via a container whose external surface is chemically and physically tuned to interact with the parent polymer. The contents of the container could then be changed without changing other important properties of the parent polymer. In this context this thesis project explores an innovative nanocontainer platform which can be introduced into phase-separating homopolymer blends. Ferritin is a naturally existing nanocontainer that can be used synthetically to package and selectively transport functional moieties to a particular phase that is either in the bulk or on the surface of a homopolymer blend system. The principal focus of this work centers on modifying the surface of wild ferritin to: (1) render modified ferritin soluble in a non-aqueous solvent; and (2) impart it with self-directing properties when exposed to a homopolymer blend surface or incorporated into the bulk of a homopolymer blend. Wild ferritin is water soluble, and this research project successfully modified wild ferritin by grafting either amine-functional poly(ethylene glycol) (PEG) or short-chain alkanes to carbodiimide activated carboxylate groups on ferritin's surface. Such modified ferritin is soluble in dichloromethane (DCM). Modification was confirmed by ion-exchange chromatography, zeta-potential measurements, and electrospray mass spectroscopy. FT-IR was used to quantify the extent of PEGylation of the reaction products through area ratios of the -C-O-C asymmetric stretching vibration of the grafted PEG chains to the

  20. Tribological effects of polymer surface modification through plastic deformation

    Indian Academy of Sciences (India)

    K O Low; K J Wong

    2011-12-01

    The efficacy of using polymers in cylindrical applications depends closely on its surface friction and wear characteristics. In this regard, a surface modification technique through plastic deformation has been implemented. Roller burnishing is commonly used to improve the surface quality of non-ferrous surfaces, but no work showed concern about roller burnishing as a polymer surface treatment process. The objective of the present work is to investigate the influence of burnishing force and burnishing speed on the friction and wear performance of acetal homopolymer and polyurethane under dry and lubricated sliding conditions. The results reveal that the coefficient of friction and wear rate decreased to a minimum value and then increased as higher burnishing force and speed were applied. It was shown that roller burnishing had favourable prospective to be utilized as a valuable polymer surface treatment technique.

  1. Homopolymer tract length dependent enrichments in functional regions of 27 eukaryotes and their novel dependence on the organism DNA (G+C% composition

    Directory of Open Access Journals (Sweden)

    Marx Kenneth A

    2004-12-01

    Full Text Available Abstract Background DNA homopolymer tracts, poly(dA.poly(dT and poly(dG.poly(dC, are the simplest of simple sequence repeats. Homopolymer tracts have been systematically examined in the coding, intron and flanking regions of a limited number of eukaryotes. As the number of DNA sequences publicly available increases, the representation (over and under of homopolymer tracts of different lengths in these regions of different genomes can be compared. Results We carried out a survey of the extent of homopolymer tract over-representation (enrichment and over-proportional length distribution (above expected length primarily in the single gene documents, but including some whole chromosomes of 27 eukaryotics across the (G+C% composition range from 20 – 60%. A total of 5.2 × 107 bases from 15,560 cleaned (redundancy removed sequence documents were analyzed. Calculated frequencies of non-overlapping long homopolymer tracts were found over-represented in non-coding sequences of eukaryotes. Long poly(dA.poly(dT tracts demonstrated an exponential increase with tract length compared to predicted frequencies. A novel negative slope was observed for all eukaryotes between their (G+C% composition and the threshold length N where poly(dA.poly(dT tracts exhibited over-representation and a corresponding positive slope was observed for poly(dG.poly(dC tracts. Tract size thresholds where over-representation of tracts in different eukaryotes began to occur was between 4 – 11 bp depending upon the organism (G+C% composition. The higher the GC%, the lower the threshold N value was for poly(dA.poly(dT tracts, meaning that the over-representation happens at relatively lower tract length in more GC-rich surrounding sequence. We also observed a novel relationship between the highest over-representations, as well as lengths of homopolymer tracts in excess of their random occurrence expected maximum lengths. Conclusions We discuss how our novel tract over

  2. Synthesis and aqueous solution properties of novel sugar methacrylate-based homopolymers and block copolymers.

    Science.gov (United States)

    Narain, Ravin; Armes, Steven P

    2003-01-01

    We report the facile preparation of a range of novel, well-defined cyclic sugar methacrylate-based polymers without recourse to protecting group chemistry. 2-Gluconamidoethyl methacrylate (GAMA) and 2-lactobionamidoethyl methacrylate (LAMA) were prepared directly by reacting 2-aminoethyl methacrylate with D-gluconolactone and lactobionolactone, respectively. Homopolymerization of GAMA and LAMA by atom transfer radical polymerization (ATRP) gave reasonably low polydispersities as judged by aqueous gel permeation chromatography. A wide range of sugar-based block copolymers were prepared using near-monodisperse macroinitiators based on poly(ethylene oxide) [PEO], poly(propylene oxide) [PPO], or poly(e-caprolactone) [PCL] and/or by sequential monomer addition of other methacrylic monomers such as 2-(diethylamino)ethyl methacrylate [DEA], 2-(diisopropylaminoethyl methacrylate [DPA], or glycerol monomethacrylate [GMA]. The reversible micellar self-assembly of selected sugar-based block copolymers [PEO23-GAMA50-DEA100, PEO23-LAMA30-DEA50, PPO33-GAMA50, and PPO33-LAMA50] was studied in aqueous solution as a function of pH and temperature using dynamic light scattering, transmission electron microscopy, surface tensiometry, and 1H NMR spectroscopy.

  3. Conducting Polymers Functionalized with Phthalocyanine as Nitrogen Dioxide Sensors

    Directory of Open Access Journals (Sweden)

    S. D. Deshpande

    2002-05-01

    Full Text Available The conducting polymers such as polyaniline, polypyrrole and polythiophene were functionalized with copper phthalocyanine using chemical oxidation method. The obtained polymers viz. PANI-CuPc, PPy-CuPc and PT-CuPc were studied as chemical sensors by their response characteristics after exposure to various chemical vapors such as methanol, ammonia and nitrogen dioxide. The results obtained showed that these polymers have moderate sensitivity towards the methanol as well as ammonia vapors whereas they show tremendous sensitivity towards nitrogen dioxide vapors. The sensitivity factor of as high as 50,000 was obtained for PT-CuPc polymers in nitrogen dioxide. In comparison to this, the sensitivity factors of about 100 and 40 were obtained, when these polymers were exposed to ammonia and methanol vapors. The very high selectivity towards the nitrogen dioxide was explained on the basis of charge transfer complex formed between, the phthalocyanine donor and nitrogen dioxide acceptor molecules. On the other hand, ammonia becomes a competing electron donor in CuPc containing conducting polymers. The very low response towards the methanol may be explained on the basis very little charge transfer / interaction between CuPc containing polymers and methanol. Thus, CuPc incorporated conducting polymers have much higher selectivity than their original homopolymer.

  4. N,N'-(Hexane-1,6-diylbis(4-methyl-N-(oxiran-2-ylmethylbenzenesulfonamide: Synthesis via cyclodextrin mediated N-alkylation in aqueous solution and further Prilezhaev epoxidation

    Directory of Open Access Journals (Sweden)

    Julian Fischer

    2013-12-01

    Full Text Available N-alkylation of N,N'-(hexane-1,6-diylbis(4-methylbenzenesulfonamide with allyl bromide and subsequent Prilezhaev reaction with m-chloroperbenzoic acid to give N,N'-(hexane-1,6-diylbis(4-methyl-N-(oxiran-2-ylmethylbenzenesulfonamide is described. This twofold alkylation was performed in aqueous solution, whereby α-, and randomly methylated β-cyclodextrin were used as adequate phase transfer catalysts and the cyclodextrin–guest complexes were characterized by 1H NMR and 2D NMR ROESY spectroscopy. Finally, the curing properties of the diepoxide with lysine-based α-amino-ε-caprolactam were analyzed by rheological measurements.

  5. Linear, first and second-order, unconditionally energy stable numerical schemes for the phase field model of homopolymer blends

    Science.gov (United States)

    Yang, Xiaofeng

    2016-12-01

    In this paper, we develop a series of efficient numerical schemes to solve the phase field model for homopolymer blends. The governing system is derived from the energetic variational approach of a total free energy, that consists of a nonlinear logarithmic Flory-Huggins potential, and a gradient entropy with a concentration-dependent de-Gennes type coefficient. The main challenging issue to solve this kind of models numerically is about the time marching problem, i.e., how to develop suitable temporal discretizations for the nonlinear terms in order to preserve the energy stability at the discrete level. We solve this issue in this paper, by developing the first and second order temporal approximation schemes based on the "Invariant Energy Quadratization" method, where all nonlinear terms are treated semi-explicitly. Consequently, the resulting numerical schemes lead to a symmetric positive definite linear system to be solved at each time step. The unconditional energy stabilities are further proved. Various numerical simulations of 2D and 3D are presented to demonstrate the stability and the accuracy of the proposed schemes.

  6. Molecular Weight and Crystallization Temperature Effects on Poly(ethylene terephthalate (PET Homopolymers, an Isothermal Crystallization Analysis

    Directory of Open Access Journals (Sweden)

    Leonardo A. Baldenegro-Perez

    2014-02-01

    Full Text Available The isothermal crystallization of poly(ethylene terephthalate (PET homopolymers with different molecular weight was studied in a wide temperature range (140–230 °C using different experimental techniques. Three different morphological regions, labeled r1, r2 and r3, were distinguished as a function of crystallization temperature (Tc. In r1 (low Tc crystallized samples were characterized by a low crystalline degree with a small spherulite texture containing thin crystals. In r2 (intermediate Tc samples showed medium size spherulites composed of two distinct crystalline families (thin and thick crystals. In this temperature range, the crystallization exhibited a maximum value and it was associated with a high content of secondary crystals. In r3 (high Tc, samples presented considerable amorphous zones and regions consisting of oversized spherulites containing only thick crystals. Time-resolved wide-angle X-ray diffraction measurements, using synchrotron radiation, indicated a rapid evolution of the crystalline degree within the second region, in contrast with the quite slow evolution observed in the third region. On the other hand, by small-angle X-ray scattering (SAXS and time-resolved SAXS experiment, it was found that the long period (L as well as the lamellar thickness (lc increase as a function of Tc, corroborating the formation of the thickest crystals in the third region. From all these observations, a morphological model was proposed for each region.

  7. Polymers of intrinsic microporosity with dinaphthyl and thianthrene segments

    KAUST Repository

    Du, Naiying

    2010-10-26

    Novel intrinsically microporous homopolymers and copolymers derived from PIM-1 monomers (5,5,6,6-tetrahydroxy-3,3,3,3-tetramethylspirobisindane and 2,3,5,6-tetrafluoroterephthalonitrile) with two additional monomers- tetrahydroxydinaphthyl and tetrafluorotetraoxide thianthrene-are reported as potential materials for membrane-based gas separations. The resulting copolymers prevent efficient space packing of the stiff polymer chains and consequently exhibit analogous behavior to that of PIM-1, the most widely reported polymer in this class of materials. In addition, the copolymerization provides high molecular weight copolymers and low polydispersity if the polymerization reactions were conducted at elevated temperature for an extended period of time. Detailed structural characterization of the new monomers and polymers was determined by 1H and 19F nuclear magnetic resonance spectroscopy (NMR). The thermal properties were detected by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Polymer free volume was calculated from the polymer density and specific van der Waals volume. Under the same testing conditions, the homopolymer containing thianthrene units and most of the analogous copolymers have an excellent combination of properties with good film-forming characteristics. The gas transport properties show higher selectivity for gas pairs such as O 2/N2, CO2/N2, and H 2/N2 with a corresponding decrease in permeability compared to PIM-1. This work also demonstrates that significant improvements in properties may be obtained through copolymers of intrinsic microporosity (CoPIM)s. Furthermore, this work extends the spectrum of high molecular weight soluble PIMs beyond those reported previously. © 2010 American Chemical Society.

  8. Polymer fractionation

    Energy Technology Data Exchange (ETDEWEB)

    Hadermann, A. F.

    1985-04-09

    Soluble polymers are fractionated according to molecular weight by cryogenically comminuting the polymer and introducing the polymer particles, while still in the active state induced by cryogenic grinding, into a liquid having a solvent power selected to produce a coacervate fraction containing high molecular weight polymer species and a dilute polymer solution containing lower molecular weight polymer species. The coacervate may be physically separated from the solution and finds use in the production of antimisting jet fuels and the like.

  9. Biodegradable Polymers

    OpenAIRE

    Isabelle Vroman; Lan Tighzert

    2013-01-01

    Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources) or from biological resources (renewable resources). In general natural polymers offer fewer advantages than synthetic polymers. ...

  10. Amine-functionalized polypyrrole: Inherently cell adhesive conducting polymer.

    Science.gov (United States)

    Lee, Jae Y; Schmidt, Christine E

    2015-06-01

    Electrically conducting polymers (CPs) have been recognized as novel biomaterials that can electrically communicate with biological systems. For their tissue engineering applications, CPs have been modified to promote cell adhesion for improved interactions between biomaterials and cells/tissues. Conventional approaches to improve cell adhesion involve the surface modification of CPs with biomolecules, such as physical adsorption of cell adhesive proteins and polycationic polymers, or their chemical immobilization; however, these approaches require additional multiple modification steps with expensive biomolecules. In this study, as a simple and effective alternative to such additional biomolecule treatment, we synthesized amine-functionalized polypyrrole (APPy) that inherently presents cell adhesion-supporting positive charges under physiological conditions. The synthesized APPy provides electrical activity in a moderate range and a hydrophilic surface compared to regular polypyrrole (PPy) homopolymers. Under both serum and serum-free conditions, APPy exhibited superior attachment of human dermal fibroblasts and Schwann cells compared to PPy homopolymer controls. Moreover, Schwann cell adhesion onto the APPy copolymer was at least similar to that on poly-l-lysine treated PPy controls. Our results indicate that amine-functionalized CP substrates will be useful to achieve good cell adhesion and potentially electrically stimulate various cells. In addition, amine functionality present on CPs can further serve as a novel and flexible platform to chemically tether various bioactive molecules, such as growth factors, antibodies, and chemical drugs. © 2014 Wiley Periodicals, Inc.

  11. Designing of superporous cross-linked hydrogels containing acrylic-based polymer network

    Directory of Open Access Journals (Sweden)

    Ray Debajyoti

    2008-01-01

    Full Text Available Biodegradable cross-linked polymer, 2-hydroxyethyl methacrylate-co-acrylic acid was synthesized by free radical polymerization technique using N,N"-methylene-bis-acrylamide as cross-linker and benzoyl peroxide as reaction initiator. FT-IR, 1 H-NMR, scanning electron microscopy (SEM, and thermogravimetric analysis (TGA studies of the copolymer along with homopolymers were carried out. FT-IR studies showed no interactions on copolymerization. SEM studies of the copolymer were carried out and mean particle size was found to be 50 µm. TGA analysis indicated an increase in thermal stability by cross-linking the polymer network. Swelling behavior of the copolymer showed more swelling by increasing pH of the medum and the prepared polymer was found to be biodegradable. The prepared cross-linked polymer system holds good for further drug delivery studies in connection to its super swelling and biodegradability.

  12. Ab Initio MO study on the nucleophilic oxirane ring opening of exo and endo Aflatoxin B{sub 1} 8,9-Oxide; Ekiso oyobi endo Aflatoxin B{sub 1} 8,9-Oxide no kyukaku kaikan hanno ni taisuru Ab Initio ho ni yoru kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Okajima, Toshiya; Hashikawa, Akane [Saga University, Saga (Japan). Department of Chemistry

    1999-08-10

    The difference of the reactivity for S{sub N}2 type oxirane ring opening of exo and endo Aflatoxin B{sub 1} (AFB{sub 1}) 8,9-oxide (exo-1 and endo-1, respectively) was analyzed with ab initio molecular orbital theory. All stationary points including transition-state structures were optimized with no geometry constraint at the RHF/3-21G basis set, and energies were evaluate at Becke3LYP/3-21G level based on the RHF/3-21G geometries. The calculation clarified the following three points: (1) the activation energy ({delta}E{sup {ne}}) for endo attacking of NH{sub 3} molecule (the reaction with exo derivatives containing exo-1) is considerably smaller than those for exo attacking (the reaction with endo ones containing endo-1), (2) the reactivity for nucleophilic oxirane ring opening is controlled by the distortion of LUMO{sub C-O} of oxirane ring, which is probably caused by exo/endo relationship between oxirane ring and five-membered dihydrofurano ring (B) with respect to A ring, and (3) the remaining part (inclusing coumarin skeleton) of AFB{sub 1} oxid has little influence on the geometry around the reaction center and the activation energy. (author)

  13. Neutron and light scattering studies of polymers adsorbed on laponite

    CERN Document Server

    Nelson, A R J

    2002-01-01

    The adsorption of poly(ethylene oxide) (PEO) and various poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (Pluronic) copolymers onto the synthetic clay Laponite, was investigated using Small Angle Neutron Scattering (SANS) and Dynamic Light Scattering (DLS). The Laponite particles are anisotropic, with a relatively high aspect ratio; but are the same order of magnitude in size as the polymer radius of gyration. Consequently, the particles present a radically different adsorption geometry compared to a locally planar interface, that is assumed by the majority of adsorption studies. The PEO homo-polymer formed thin layers, with the layer thickness being much smaller on the face than on the edge of the particle. Furthermore, the face thickness remained constant with increasing molecular weight, unlike the edge thickness, which grew with a small power law dependence on the molecular weight. Although the hydrodynamic thicknesses (DLS) were larger than those observed with SANS, the layer thicknesses ...

  14. Tuning the critical solution temperature of polymers by copolymerization

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Bernhard; Chudoba, Richard; Dzubiella, Joachim, E-mail: joachim.dzubiella@helmholtz-berlin.de [Institut für Weiche Materie und Funktionale Materialien, Helmholtz-Zentrum Berlin, 14109 Berlin (Germany); Institut für Physik, Humboldt-Universität zu Berlin, 12489 Berlin (Germany); Heyda, Jan [Department of Physical Chemistry, University of Chemistry and Technology, Prague, 166 28 Praha 6 (Czech Republic)

    2015-12-28

    We study statistical copolymerization effects on the upper critical solution temperature (CST) of generic homopolymers by means of coarse-grained Langevin dynamics computer simulations and mean-field theory. Our systematic investigation reveals that the CST can change monotonically or non-monotonically with copolymerization, as observed in experimental studies, depending on the degree of non-additivity of the monomer (A-B) cross-interactions. The simulation findings are confirmed and qualitatively explained by a combination of a two-component Flory-de Gennes model for polymer collapse and a simple thermodynamic expansion approach. Our findings provide some rationale behind the effects of copolymerization and may be helpful for tuning CST behavior of polymers in soft material design.

  15. Biodegradable Polymers

    Directory of Open Access Journals (Sweden)

    Isabelle Vroman

    2009-04-01

    Full Text Available Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources or from biological resources (renewable resources. In general natural polymers offer fewer advantages than synthetic polymers. The following review presents an overview of the different biodegradable polymers that are currently being used and their properties, as well as new developments in their synthesis and applications.

  16. Polymer electronics

    CERN Document Server

    Hsin-Fei, Meng

    2013-01-01

    Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

  17. Applications of functional polymer brushes for nanoparticle uptake and prevention of protein adsorption

    Science.gov (United States)

    Arifuzzaman, Shafi M.

    The central theme of this Ph.D. dissertation is to develop novel multifunctional polymer coatings for understanding partition of proteins and nanoparticles on polymers grafted to flat surfaces (so-called brushes). Systematic investigation of the adsorption phenomena is accomplished by utilizing surface-anchored assemblies comprising grafted polymers with variation in physical properties (i.e., length or/and grafting density) and chemical functionality. The chemical composition of the brush is tailored by either "chemical coloring" of a parent homopolymer brush with selective chemical moieties or by sequential growth of two chemically dissimilar polymer blocks. We present preparation of two types of tailor-made, surface-grafted copolymers: (1) those composed of hydrophilic and hydrophobic blocks (so-called amphiphilic polymer brushes), and (2) those comprising of anionic and cationic polymer segments (so-called polyampholyte brushes). We describe the organization of functionality in the grafted polymer brushes and the partitioning of proteins and nanoparticles using a battery of complementary analytical probes. Specifically, we address how varying the molecular weight, grafting density, and chemical composition of the brush affects adsorbtion and desorbtion of model proteins and gold nanoparticles. Our observations indicate densely-populated responsive amphiphilic polymers are very efficient in suppressing protein adsorption. In addition, we have established that the length of poly(ethylene glycol) spacers attached to a parent homopolymer brush is a key factor governing uptake of gold nanoparticles. Both grafting density and molecular weight of the coating are important in controlling the kinetics and thermodynamics of protein adsorption on surfaces. Our findings and methodologies can lead to the development of next generation environmentally friendly antifouling surfaces and will find application in medical devices, antifouling coatings and anti reflection finishes.

  18. Charge photogeneration and transport in side-chain carbazole polymers and co-polymers

    KAUST Repository

    Li, Huawei

    2011-07-01

    The photoconductivity, hole mobility and charge photogeneration efficiency of a series of side-chain carbazole homopolymers and copolymers (with azo side-chains) have been investigated. Cyclic voltammetry measurement of frontier orbitals energies show that the HOMO energy is determined by the nature and the position of attachment of the linker between the main chain and the carbazole, the azo-moiety being not relevant in this respect. Hole mobility is not influenced by the HOMO energy but seems to depend on the degree of conformational mobility of the side-chains, reaching values of the order of 10-3cm2V-1s-1 in the best cases. The HOMO energy is instead extremely important when considering photogeneration efficiency, that can change by 10 orders of magnitude depending on the density of the carbazole side-chains in co-polymers and on the linker nature and attachment position. © 2011 Elsevier B.V. All rights reserved.

  19. Design and characterization of well-defined supramolecular polymers

    Science.gov (United States)

    Schaefer, Kathleen; Kade, Matthew; Hawker, Craig; Kramer, Edward

    2007-03-01

    Polymeric materials with well-defined and controllable temperature dependent properties are of interest both for technological applications and fundamental physical studies. Melt processing requires low viscosity, while resistance to fracture is desirable at material operating temperatures, and these two properties are often mutually exclusive. Through controlled radical polymerization (ATRP) we have synthesized tailor-made polymers with MHB groups specifically located at one or both chain ends or randomly along the backbone to provide thermal tunability, and by changing the nature of the MHB group (complementary or self-complementary) we can control the specificity and type of the polymer-polymer interaction. As a simple model system, we investigate the case of two end-functional MHB homopolymers that form a novel supramolecular diblock copolymer. Two energies are expected to be important in this system---χN, the Flory-Huggins interaction parameter times the degree of polymerization, which describes the polymer-polymer interaction, and ɛ, the binding energy of the MHB group. Using deuterium labeled polymers in various multilayer thin film structures, dynamic secondary ion mass spectrometry (dSIMS) allows each of these parameters to be measured independently and these values used to design technologically and physically interesting new materials.

  20. Structural characterization of synthetic polymers using thermal-assisted atmospheric pressure glow discharge mass spectrometry.

    Science.gov (United States)

    Zhang, Ning; Zhou, Yueming; Zhen, Cheng; Li, Yafeng; Xiong, Caiqiao; Wang, Jiyun; Li, Huayi; Nie, Zongxiu

    2012-11-07

    With the development of material science and the practical needs of the polymer industry, rapid characterization of synthetic polymers using mass spectrometry is of sustainable interest. Herein a new method for characterizing synthetic polymers using thermal-assisted atmospheric pressure glow discharge mass spectrometry (TA-APGD-MS) is established. After illustration of the mechanism of ion formation, typical polymer samples such as polystyrene (PS), polyoxymethylene (POM) and poly (butanediol succinate) (PBS) were directly characterized at the molecular level using TA-APGD-MS. The thermal degradation products of synthetic polymers including monomer units and/or other fragments were rapidly detected by tandem mass spectrometry, providing rich information about the chemical composition for the structural characterization of homo- and co-polymers. The result suggests that TA-APGD-MS allows direct and rapid analysis of both synthetic homo-polymers and co-polymers under ambient conditions without any sample pretreatment. This method features high throughput, high sensitivity and rich information, showing promising applications in polymer science.

  1. Versatile Approach to Access the Low Temperature Thermodynamics of Lattice Polymers and Proteins

    Science.gov (United States)

    Wüst, Thomas; Landau, David P.

    2009-05-01

    We show that Wang-Landau sampling, combined with suitable Monte Carlo trial moves, provides a powerful method for both the ground state search and the determination of the density of states for the hydrophobic-polar (HP) protein model and the interacting self-avoiding walk (ISAW) model for homopolymers. We obtain accurate estimates of thermodynamic quantities for HP sequences with >100 monomers and for ISAWs up to >500 monomers. Our procedure possesses an intrinsic simplicity and overcomes the limitations inherent in more tailored approaches making it interesting for a broad range of protein and polymer models.

  2. FOR STIMULI-RESPONSIVE POLYMERS WITH ENHANCED EFFICIENCY IN RESERVOIR RECOVERY PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    Charles McCormick; Roger Hester

    2002-04-29

    To date, our synthetic research efforts have been focused on the development of stimuli-responsive water-soluble polymers designed for use in enhanced oil recovery (EOR) applications. These model systems are structurally tailored for potential application as viscosifiers and/or mobility control agents for secondary and tertiary EOR methods. The following report discloses the progress of our ongoing research of polyzwitterions, polymers derived from monomers bearing both positive and negative charges, that show the ability to sustain or increase their hydrodynamic volume (and thus, solution viscosity) in the presence of electrolytes. Such polymers appear to be well-suited for use under conditions similar to those encountered in EOR operations. Additionally, we disclose the synthesis and characterization of a well-defined set of polyacrylamide (PAM) homopolymers that vary by MW. The MW of the PAM samples is controlled by addition of sodium formate to the polymerization medium as a conventional chain transfer agent. Data derived from polymer characterization is used to determine the kinetic parameter C{sub CT}, the chain transfer constant to sodium formate under the given polymerization conditions. The PAM homopolymer series will be employed in future set of experiments designed to test a simplified intrinsic viscosity equation. The flow resistance of a polymer solution through a porous medium is controlled by the polymer's hydrodynamic volume, which is strongly related to it's intrinsic viscosity. However, the hydrodynamic volume of a polymer molecule in an aqueous solution varies with fluid temperature, solvent composition, and polymer structure. This report on the theory of polymer solubility accentuates the importance of developing polymer solutions that increase in intrinsic viscosity when fluid temperatures are elevated above room conditions. The intrinsic viscosity response to temperature and molecular weight variations of three polymer solutions

  3. PHOTOREFRACTIVE POLYMERS

    NARCIS (Netherlands)

    Morichere, D; Malliaras, G.G; Krasnikov, V.V.; Bolink, H.J; Hadziioannou, G

    1995-01-01

    The use of polymers as photorefractive materials offers many advantages : flexibility in synthesis, doping, processing and low cost. The required functionalities responsible for photorefractivity, namely charge generation, transport, trapping and linear electrooptic effect are given in the polymer w

  4. PHOTOREFRACTIVE POLYMERS

    NARCIS (Netherlands)

    Morichere, D; Malliaras, G.G; Krasnikov, V.V.; Bolink, H.J; Hadziioannou, G

    1995-01-01

    The use of polymers as photorefractive materials offers many advantages : flexibility in synthesis, doping, processing and low cost. The required functionalities responsible for photorefractivity, namely charge generation, transport, trapping and linear electrooptic effect are given in the polymer w

  5. Influence of annealing and blending of photoactive polymers on their crystalline structure.

    Science.gov (United States)

    Ruderer, Matthias A; Prams, Stefan M; Rawolle, Monika; Zhong, Qi; Perlich, Jan; Roth, Stephan V; Müller-Buschbaum, Peter

    2010-12-02

    Thin photoactive polymer films of poly(3-octylthiophene-2,5-diyl) (P3OT) and poly(2,5-di(hexyloxy)cyanoterephthalylidene) (CN-PPV) are investigated. With X-ray reflectivity measurements, a linear concentration-thickness dependence is found for both polymers and the molecular weight of CN-PPV is determined from this concentration-thickness dependence. Based on the molecular weights, the critical blending ratio is determined. Grazing incidence wide-angle X-ray scattering (GIWAXS) is used to probe the crystallinity of thin films and to determine characteristic length scales of the crystalline structure. Moreover, the orientation of the crystalline parts regarding the substrate of both the homopolymer and the blended films is probed with GIWAXS. Temperature annealing is found to improve the crystallization for both homopolymers. In addition, reorientation of the predominant crystalline structures takes place. Blending both polymers reduces or even suppresses the crystallization during spin coating as well as temperature annealing. Absorption measurements complement the structural investigations.

  6. Polymer Brushes

    NARCIS (Netherlands)

    Vos, de W.M.; Kleijn, J.M.; Keizer, de A.; Cosgrove, T.; Cohen Stuart, M.A.

    2010-01-01

    A polymer brush can be defined as a dense array of polymers end-attached to an interface that stretch out into the surrounding medium. Polymer brushes have been investigated for the past 30 years and have shown to be an extremely useful tool to control interfacial properties. This review is intended

  7. 高凝析液页岩气处理集成环氧乙烷生产过程建模与模拟%Modeling and simulation of NGLs-rich shale gas processing integrated with oxirane production

    Institute of Scientific and Technical Information of China (English)

    郑洪昊; 邓春; 冯霄

    2015-01-01

    富含凝析液页岩气的化工利用能有效缓解我国当前资源和能源的短缺状况,提高我国化工产品的成本优势.本文提出高凝析液页岩气处理过程与环氧乙烷生产过程耦合的新型工艺流程,利用Aspen Hysys并结合严格的动力学模型对该过程进行建模和模拟.经初步的收益分析可知税后财务净现值相较集成前提高了36.76%.本文的工作可为高凝析液页岩气的化工利用提供一种新颖的方案和思路.%Preparing for the exploration, utilization and the development of NGLs-rich shale gas in advance and speeding up the research of related industries can effectively alleviate the shortage of current resources and energy and increase the cost advantage of domestic chemical product. Thus the investigating downstream utilization of shale gas as a profitable chemical industry feedstock has important significance. In this paper, on the basis of the proposed process via cracking gas recycling to dehydration in the literature, a novel process for NGLs-rich shale gas processing integrated with oxirane production is proposed and the process modeling and simulation is conducted by using Aspen Hysys. It is noteworthy that the one of the features of the proposed process design is the cracker reactor of ethane and the process of partial oxidation of ethane to ethylene oxide in microchannel reactors are modeled rigorously as plug flow reactors with rate kinetic equations. This process design has higher degrees of process integration and equipment sharing and thus its process utilities consumption and plant capital cost are relatively lower than those of other process designs without integrated with oxirane or ethylene production. This work can provide a novel and feasible method for the further utilization of NGLs-rich shale gas in the process of shale gas treatment. In addition, the most suitable range of the process operation conditions are determined by sensitivity analysis. In this

  8. Polymères Liquides Ioniques (PIL) Réactifs et Nanostructures à Partir de Copolymères à Blocs Composés d’un Bloc PIL

    OpenAIRE

    Coupillaud, Paul

    2014-01-01

    The aim of this PhD work is to expand the scope of engineered imidazolium-based poly(ionicliquid)s (PILs) and their related PIL-block copolymers (PIL BCPs).The use of the imidazolium-based PILs as true reactive polymers for organocatalysis and post-chemicalmodification is first described. Miscellaneous air-stable PIL derivatives featuring various counter-anions(e.g. bromides, hydrogen carbonates, carboxylates), including homopolymers, statistical copolymers ofstyrenic-type and crosslinked cop...

  9. HPLC analysis of synthetic polymers on short monolithic columns.

    Science.gov (United States)

    Maksimova, Elena; Vlakh, Evgenia; Sinitsyna, Ekaterina; Tennikova, Tatiana

    2013-12-01

    Ultrashort monolithic columns (disks) were thoroughly studied as efficient stationary phases for precipitation-dissolution chromatography of synthetic polymers. Gradient elution mode was applied in all chromatographic runs. The mixtures of different flexible chain homopolymers, such as polystyrenes, poly(methyl methacrylates), and poly(tert-butylmethacrylates) were separated according to their molecular weights on both commercial poly(styrene-co-divinylbenzene) disks (12 id × 3 mm and 5 × 5 mm) and lab-made monolithic columns (4.6 id × 50 mm) filled with supports of different hydrophobicity. The experimental conditions were optimized to reach fast and highly efficient separation. It was observed that, similar to the separation of monoliths of other classes of (macro)molecules (proteins, DNA, oligonucleotides), the length of column did not affect the peak resolution. A comparison of the retention properties of the poly(styrene-co-divinylbenzene) disk-shaped monoliths with those based on poly(lauryl methacrylate-co-ethylene dimethacrylate), poly(butyl methacrylate-co-ethylene dimethacrylate), and poly(glycidyl methacrylate-co-ethylene dimethacrylate) supports demonstrated the obvious effect of surface chemistry on the resolution factor. Additionally, the results of the discussed chromatographic mode on the fast determination of the molecular weights of homopolymers used in this study were compared to those established by SEC on columns packed with sorbent beads of a similar nature to the monoliths. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. On the polymer physics origins of protein folding thermodynamics

    Science.gov (United States)

    Taylor, Mark P.; Paul, Wolfgang; Binder, Kurt

    2016-11-01

    A remarkable feature of the spontaneous folding of many small proteins is the striking similarity in the thermodynamics of the folding process. This process is characterized by simple two-state thermodynamics with large and compensating changes in entropy and enthalpy and a funnel-like free energy landscape with a free-energy barrier that varies linearly with temperature. One might attribute the commonality of this two-state folding behavior to features particular to these proteins (e.g., chain length, hydrophobic/hydrophilic balance, attributes of the native state) or one might suspect that this similarity in behavior has a more general polymer-physics origin. Here we show that this behavior is also typical for flexible homopolymer chains with sufficiently short range interactions. Two-state behavior arises from the presence of a low entropy ground (folded) state separated from a set of high entropy disordered (unfolded) states by a free energy barrier. This homopolymer model exhibits a funneled free energy landscape that reveals a complex underlying dynamics involving competition between folding and non-folding pathways. Despite the presence of multiple pathways, this simple physics model gives the robust result of two-state thermodynamics for both the cases of folding from a basin of expanded coil states and from a basin of compact globule states.

  11. Correlation hole effect in comblike copolymer systems obtained by hydrogen bonding between homopolymers and end-functionalized oligomers

    NARCIS (Netherlands)

    Huh, J; Ikkala, O; tenBrinke, G

    1997-01-01

    This paper addresses concentration fluctuations in comblike copolymer systems obtained by hydrogen bonding between polymers and end-functionalized oligomers. Monodisperse block copolymer systems in the homogeneous melt exhibit small-angle X-ray scattering peaks at finite nonzero angle due to

  12. Polymérisation de l’éthylène : de l’homopolymérisation radicalaire à la copolymérisation hybride radicalaire / catalytique

    OpenAIRE

    2010-01-01

    This work aims to study ethylene polymerization from the free radical polymerization process to the copolymerization by a hybrid radical/catalytic mechanism. PE is synthesized by free radical polymerization under milder experimental conditions than industrial ones (P>1000 bar and T>100°C). Indeed free radical polymerization of ethylene is efficient even down to pressure of 5 bar and temperature of 10°C. Several unexpected behaviors are observed such as a high solvent activation effect. Beside...

  13. SYNTHESIS AND CHARACTERIZATION OF A METHACRYLATE POLYMER WITH SIDE CHAIN KETONE AND ITS DERIVATIVES

    Institute of Scientific and Technical Information of China (English)

    Ibrahim Erol; Cemal Cifci

    2011-01-01

    A new type of methacrylate monomer, 2-(4-benzoylphenoxy)-2-oxoethyl methylacrylate (BOEMA) was synthesized. The radical homopolymerization of BOEMA was performed at 65℃ in a 1,4-dioxane solution with benzoyl peroxide as an initiator. The oxime and thiosemicarbazone derivatives of poly[2-(4-benzoylphenoxy)-2-oxoethyl methylacrylate] poly(BOEMA) were prepared with hydroxylamine hydrochloride, and thiosemicarbazone hydrochloride,respectively. The monomer and its homopolymer were characterized with Fourier transform infrared and NMR techniques.The thermal stabilities of poly(BOEMA) and its derivatives were investigated with thermogravimetric analysis and differential scanning calorimetry. The ultraviolet stability of the polymers was compared. The antibacterial and antifungal effects of the monomer and the polymer and its derivatives were also investigated on various bacteria and fungi. The activation energies of the thermal degradation of the polymers were calculated with the Ozawa and Kissinger methods.

  14. Cylindrical polymer brushes with dendritic side chains by iterative anionic reactions

    KAUST Repository

    Zhang, Hefeng

    2015-05-01

    We report in this paper an easy method for the synthesis of cylindrical polymer brushes with dendritic side chains through anionic reaction. The synthesis is accomplished by iteratively grafting a living block copolymer, polyisoprene-. b-polystyrenyllithium (PI-. b-PSLi), to the main chain and subsequently to the branches in a divergent way. PI segment is short and serves as a precursor for multifunctional branching unit. The grafting reaction involves two successive steps: i) epoxidation of internal double bonds of PI segments, either in main chain or side chains; ii) ring-opening addition to the resulting epoxy group by the living PI-. b-PSLi. Repeating the two steps affords a series of cylindrical polymer brushes with up to 3rd generation and extremely high molecular weight. The branching multiplicity depends on the average number of oxirane groups per PI segment, usually ca. 8 in the present work. The high branching multiplicity leads to tremendous increase in molecular weights of the cylindrical products with generation growth. Several series of cylindrical polymer brushes with tunable aspect ratios are prepared using backbones and branches with controlled lengths. Shape anisotropy is investigated in dilute solution using light scattering technique. Worm-like single molecular morphology with large persistence length is observed on different substrates by atomic force microscopy.

  15. Novel reactions of quadricyclane: a new route to monomers for low-absorbing polymers in 157-nm photoresists

    Science.gov (United States)

    Marsella, John A.; Abdourazak, Atteye H.; Carr, Richard V. C.; Markley, Thomas J.; Robertson, Eric A., III

    2004-05-01

    Norbornene monomers with fluorinated substituents are often used in copolymers targeted for photoresist applications at 157 nm. Homopolymers of these norbornene monomers typically exhibit an absorption coefficient greater than 1.5 μm-1. Comonomers, which are often perfluoroolefins, are needed to meet the transparency requirement for 157 nm lithography, namely an absorption coefficient less than 1.0 μm-1. Clearly, a norbornene monomer that gives a homopolymer with an optical density less than 1.0 μm-1 would require less, if any, perfluoroolefin comonomer, providing a distinct advantage in the production of the base resin. Research in Air Products and Chemicals" labs has led to the discovery that fluorinated hydroxyalkyl ether derivatives of norbornene ring systems with suitable substitution patterns can give homopolymers with absorption coefficients of less than 1 μm-1. The monomers are produced via a novel reaction pathway involving quadricyclane. This pathway provides a versatile and rich synthetic chemistry, and the potential for eliminating, or at least substantially decreasing, perfluoroolefin incorporation into 157 nm photoresists. Specific examples of these reactions are discussed here, along with VUV-VASE and etch resistance data for a series of polymers derived from quadricyclane reactions.

  16. Solvation of polymers as mutual association. I. General theory

    Science.gov (United States)

    Dudowicz, Jacek; Freed, Karl F.; Douglas, Jack F.

    2013-04-01

    A Flory-Huggins (FH) type lattice theory of self-assembly is generalized to describe the equilibrium solvation of long polymer chains B by small solvent molecules A. Solvation is modeled as a thermally reversible mutual association between the polymer and a relatively low molar mass solvent. The FH Helmholtz free energy F is derived for a mixture composed of the A and B species and the various possible mutual association complexes AiB, and F is then used to generate expressions for basic thermodynamic properties of solvated polymer solutions, including the size distribution of the solvated clusters, the fraction of solvent molecules contained in solvated states (an order parameter for solvation), the specific heat (which exhibits a maximum at the solvation transition), the second and the third osmotic virial coefficients, and the boundaries for phase stability of the mixture. Special attention is devoted to the analysis of the "entropic" contribution χs to the FH interaction parameter χ of polymer solutions, both with and without associative interactions. The entropic χs parameter arises from correlations associated with polymer chain connectivity and disparities in molecular structure between the components of the mixture. Our analysis provides the first explanation of the longstanding enigma of why χs for polymer solutions significantly exceeds χs for binary polymer blends. Our calculations also reveal that χs becomes temperature dependent when interactions are strong, in sharp contrast to models currently being used for fitting thermodynamic data of associating polymer-solvent mixtures, where χs is simply assumed to be an adjustable constant based on experience with solutions of homopolymers in nonassociating solvents.

  17. Flory theory for polymers.

    Science.gov (United States)

    Bhattacharjee, Somendra M; Giacometti, Achille; Maritan, Amos

    2013-12-18

    We review various simple analytical theories for homopolymers within a unified framework. The common guideline of our approach is the Flory theory, and its various avatars, with the attempt at being reasonably self-contained. We expect this review to be useful as an introduction to the topic at the graduate student level.

  18. Synthesis and radiation degradation of vinyl polymers with fluorine: search for improved lithographic resists. [Gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Pittman, C.U. Jr. (Univ. of Alabama, University); Chen, C.Y.; Ueda, M.; Helbert, J.N.; Kwiatkowski, J.H.

    1980-12-01

    Homopolymers of methyl ..cap alpha..-fluoroacrylate (MFA), trifluoroethyl methacrylate (TFEM), and hexafluoroisopropyl methacrylate (HFIM) were prepared, as were their methyl methacrylate (MMA) copolymers. Copolymers of vinylidene fluoride (VDF) and chlorotrifluoroethylene (CTFE) with MMA were also prepared. The radiation susceptibilities of these polymers were measured by the /sup 60/Co ..gamma..-irradiation method, in which molecular weights were measured by membrane osmometry and gel permeation chromatography (GPC). All the copolymers degraded by predominant chain scission except poly(methyl ..cap alpha..-fluoroacrylate), (PMFA), which crosslinks even at low doses (ca. 1 Mrad). The G/sub s/-G/sub x/ and G/sub s/ values of the chain scissioning polymers and copolymers are higher than those of poly(methyl methacrylate) PMMA reference. The high susceptibility of PMFA homopolymer to crosslinking is in contrast to that of poly(methyl ..cap alpha..-chloroacrylate), as we reported earlier. This effect is interpreted as resulting from extensive hydrogen fluoride and polyenyl radical formation, which leads to facile crosslinking. However, incorporation of the MFA monomer unit causes the (22/78) MFA/MMA copolymer to degrade with a larger value of G/sub s/ that PMMA. Apparently a second-order process leads to crosslinking in PMFA and this is retarded in the copolymer. In the homopolymers of HFIM and TFEM and in the HFIM-MMA and TFEM-MMA copolymers the HFIM and TFEM components facilitate degradation with negligible crosslinking. The increased degradation susceptibility of VDF and CTFE copolymers with MMA over that of PMMA is attributed to processes at the VDF or CTFE components (present in smaller concentrations (3 to 5 mole %) than the threshold levels (25 to 50% necessary for significant crosslinking).

  19. STAR POLYMERS

    OpenAIRE

    Ch. von Ferber; Yu.Holovatch

    2002-01-01

    It is our great pleasure to present a collection of papers devoted to theoretical, numerical, and experimental studies in the field of star polymers. Since its introduction in the early 80-ies, this field has attracted increasing interest and has become an important part of contemporary polymer physics. While research papers in this field appear regularly in different physical and chemical journals, the present collection is an attempt to join together the studies of star polymers showing the...

  20. Polymer Chemistry

    Science.gov (United States)

    Williams, Martha; Roberson, Luke; Caraccio, Anne

    2010-01-01

    This viewgraph presentation describes new technologies in polymer and material chemistry that benefits NASA programs and missions. The topics include: 1) What are Polymers?; 2) History of Polymer Chemistry; 3) Composites/Materials Development at KSC; 4) Why Wiring; 5) Next Generation Wiring Materials; 6) Wire System Materials and Integration; 7) Self-Healing Wire Repair; 8) Smart Wiring Summary; 9) Fire and Polymers; 10) Aerogel Technology; 11) Aerogel Composites; 12) Aerogels for Oil Remediation; 13) KSC's Solution; 14) Chemochromic Hydrogen Sensors; 15) STS-130 and 131 Operations; 16) HyperPigment; 17) Antimicrobial Materials; 18) Conductive Inks Formulations for Multiple Applications; and 19) Testing and Processing Equipment.

  1. Photochromism and diffraction grating in cyanoazobenzene polymer films

    Science.gov (United States)

    Serwadczak, M.; Wübbenhorst, M.; Kucharski, S.

    2006-08-01

    Two series of photochromic copolymathacrylates containing cyanoazobenzene chromophores as side chains were described. The series with shorter ethylene spacer between mesogen and main polymethacrylate chain was amorphous, whereas the second one with longer ethoxyethylene spacer was liquid crystalline forming smectic C mesophase above Tg. The materials were deposited on glass substrates via spin coating and casting technique to provide thin transparent films. The reversible change of refractive index of the films on illumination with white light was determined by ellipsometry. The difference of real part of the refractive index of the sample was in the range 0.0067-0.0210 depending on the polymer. Formation of diffraction grating was achieved by two beam coupling arrangement using a 532 nm laser diode . The diffraction efficiency for the first order diffraction was in the range of 1.5-2.1% for the homopolymers.

  2. Wang-Landau simulations of polymer adsorption on diluted surfaces

    Science.gov (United States)

    Martins, Paulo; Vogel, Thomas; Landau, David

    2012-02-01

    We consider a single linear lattice homopolymer in three dimensions that interacts with a diluted planar surface. A fraction p of the total number of the sites on the substrate is attractive, while the remaining 1-p remains neutral. Our focus is on the conformational transitions the polymer can experience under different environmental conditions, for instance, the surface dilution and the strength of the substrate attraction, compared to the intensity of the monomer-monomer interactions. To get insights on the phase diagram we have performed extensive Monte Carlo simulations, by using the Wang-Landau sampling, for different values of the surface attraction ɛ and the concentration of attractive sites p, specially near the surface percolation threshold pc.

  3. Effect of homopolymer poly(vinyl acetate on compatibility and mechanical properties of poly(propylene carbonate/poly(lactic acid blends

    Directory of Open Access Journals (Sweden)

    J. Gao

    2012-11-01

    Full Text Available A small amount of homopolymer poly(vinyl acetate (PVAc is used to compatibilize the biodegradable blends of poly(propylene carbonate (PPC and poly(lactic acid (PLA. Scanning electron microscopy (SEM and differential scanning calorimetry (DSC results show that PVAc is selectively localized in the PLA phase and at the interface between PPC and PLA phases. As a result, these interface-localized PVAc layers act as not only a compatibilizer to improve the phase dispersion significantly but also a bridge to increase the interfacial adhesion between PPC and PLA phases dramatically. Both of them are believed to be responsible for the enhancement in mechanical properties. This work provides a simple avenue to fabricate eco-friendly PPC/PLA blends with high performance, and in some cases, reducing the demand for petroleumbased plastics such as polypropylene.

  4. Unraveling Structure-Property Relationships in Polymer Blends for Intelligent Materials Design

    Science.gov (United States)

    Irwin, Matthew Tyler

    Block polymers provide an accessible route to structured, composite materials by combining two or more components with disparate mechanical, chemical, and electrical properties into a single bulk material with nanoscale domains. However, the characteristic lengthscale of these systems is limited, and the choice of components is restricted to those that are able to undergo microstructural ordering at accessible temperatures. This thesis details routes to overcoming these limitations through the addition of a lithium salt, a blend of homopolymers, or both. Chapter 2 describes a study wherein complex sphere phases such as the Frank-Kasper sigma phase can be observed in otherwise disordered asymmetric block polymers through the addition of a lithium salt. Chapter 3 discusses the development and characterization of a ternary polymer blend of an AB diblock copolymer and A and B homopolymers doped with a lithium salt. Detailed characterization showed that doping blends that are otherwise disordered with lithium salt induced microstructural ordering and largely recovers the phase behavior of traditional ternary polymer blends. A systematic study of the ionic conductivity of the blends at a fixed salt concentration demonstrates that, at a given composition, disordered, yet highly structured blends consistently exhibit better conductivity than polycrystalline morphologies with long range order. Chapter 4 extends the methodology of Chapter 3 and details a systematic study of the effects of cross-linker concentration on the performance of polymer electrolyte membranes produced via polymerization-induced microphase separation that exhibit a highly structured, globally disordered microstructure. Finally, Chapter 5 details efforts to develop a water filtration membrane using a polyethylene template derived from a polymeric bicontinuous microemulsion. Throughout all of this work, the goal is to better understand structure-property relationships at the molecular level in order to

  5. Polymer-mediated formation of polyoxomolybdate nanomaterials

    Science.gov (United States)

    Wan, Quan

    A polymer-mediated synthetic pathway to a polyoxomolybdate nanomaterial is investigated in this work. Block copolymers or homopolymers containing poly(ethylene oxide) (PEO) are mixed with a MoO2(OH)(OOH) aqueous solution to form a golden gel or viscous solution. As revealed by synchrotron X-ray scattering measurements, electron microscopy, and other characterization techniques, the final dark blue polyoxomolybdate product is a highly ordered simple cubic network similar to certain zeolite structure but with a much larger lattice constant of ˜5.2 nm. The average size of the cube-like single crystals is close to 1 mum. Based on its relatively low density (˜2.2 g/cm3), the nanomaterial can be highly porous if the amount of the residual polymer can be substantially reduced. The valence of molybdenum is ˜5.7 based on cerimetric titration, representing the mixed-valence nature of the polyoxomolybdate structure. The self-assembled structures (if any) of the polymer gel do not have any correlation with the final polyoxomolybdate nanostructure, excluding the possible role of polymers being a structure-directing template. On the other hand, the PEO polymer stabilizes the precursor molybdenum compound through coordination between its ether oxygen atoms and molybdenum atoms, and reduces the molybdenum (VI) precursor compound with its hydroxyl group being a reducing agent. The rare simple cubic ordering necessitates the existence of special affinities among the polyoxomolybdate nanosphere units resulted from the reduction reaction. Our mechanism study shows that the acidified condition is necessary for the synthesis of the mixed-valence polyoxomolybdate clusters, while H2O2 content modulates the rate of the reduction reaction. The polymer degradation is evidenced by the observation of a huge viscosity change, and is likely through a hydrolysis process catalyzed by molybdenum compounds. Cube-like polyoxomolybdate nanocrystals with size of ˜40 nm are obtained by means of

  6. Polymers & People

    Science.gov (United States)

    Lentz, Linda; Robinson, Thomas; Martin, Elizabeth; Miller, Mary; Ashburn, Norma

    2004-01-01

    Each Tuesday during the fall of 2002, teams of high school students from three South Carolina counties conducted a four-hour polymer institute for their peers. In less than two months, over 300 students visited the Charleston County Public Library in Charleston, South Carolina, to explore DNA, nylon, rubber, gluep, and other polymers. Teams of…

  7. The Effect of Elongational Flow on the Placement and Orientation of Nanorods in Polymer: Modeling and Experiments

    Science.gov (United States)

    Park, Jay; Kalra, Vibha; Joo, Yong

    2012-02-01

    Nanorods are often incorporated into a polymer to enhance its functionality. Gaining control over the placement of nanorods in polymer is important to improve the desired nanocomposite material property and for application like solar cell. First, we used coarse-grained molecular dynamics (CGMD) simulation to quantitatively examine the effect of elongational flow on the placement of model nanorods in homopolymer matrix. We have investigated how flow strength, concentration, interaction, and aspect ratio of nanorods affect its placement in homopolymer. As an analogous experiment, we have electrospun polyvinyl alcohol (PVA) in water with Au nanorods. The experimental result showed dispersion and alignment of Au nanorods, as predicted by the simulation. We also demonstrated selective placement of nanorods along the outer layer of fiber by co-axially electrospinning PVA/Au nanorods and pure PVA as shell and core, respectively. The material properties of the PVA/Au nanocomposite fiber are tested to show its potential application such as electromagnetic interference (EMI) shielding. The good agreements between simulation and experiment suggest that CGMD simulation can be used as a predictive tool for controlling nanorod placement in a polymer under extensional flow.

  8. Synthesis and characterization of poly(2,5-dimethoxyaniline) and poly(aniline-Co-2,5-dimethoxyaniline): The processable conducting polymers

    Indian Academy of Sciences (India)

    Bidhan C Roy; Maya Dutta Gupta; Leena Bhowmik; Jayanta K Ray

    2001-08-01

    Poly(2,5-dimethoxyaniline) (PDMOA) and its copolymers with aniline (PADMOA), which exhibit remarkably improved solubility in common organic solvents, were obtained by chemical polymerization, and characterized by a host of physical techniques. The lowering of the quinoid absorption in the IR spectra and the upshifting of the 1s envelope in the XPS spectra indicate residual doping in the XPS polymers and thermal characteristic of the polymers provide evidence for hydrogen bonding, which appear to enhance the thermal stability of the homopolymer. These polymers are highly planar and conjugated, with well-developed polaronic features, shown by the XRD, ESR and UV-spectral data. The conductivity, however, is not high and apparently may be due to localization of polaronic charges at the hydrogen-bonding sites and the increased proportion of the insulating methoxy component in the polymer matrix.

  9. Communication: One size fits all: Equilibrating chemically different polymer liquids through universal long-wavelength description

    Science.gov (United States)

    Zhang, Guojie; Stuehn, Torsten; Daoulas, Kostas Ch.; Kremer, Kurt

    2015-06-01

    Mesoscale behavior of polymers is frequently described by universal laws. This physical property motivates us to propose a new modeling concept, grouping polymers into classes with a common long-wavelength representation. In the same class, samples of different materials can be generated from this representation, encoded in a single library system. We focus on homopolymer melts, grouped according to the invariant degree of polymerization. They are described with a bead-spring model, varying chain stiffness and density to mimic chemical diversity. In a renormalization group-like fashion, library samples provide a universal blob-based description, hierarchically backmapped to create configurations of other class-members. Thus, large systems with experimentally relevant invariant degree of polymerizations (so far accessible only on very coarse-grained level) can be microscopically described. Equilibration is verified comparing conformations and melt structure with smaller scale conventional simulations.

  10. Arabidopsis dynamin-related protein 1A polymers bind, but do not tubulate, liposomes

    Energy Technology Data Exchange (ETDEWEB)

    Backues, Steven K. [Department of Biochemistry, University of Wisconsin - Madison, 433 Babcock Dr., Madison, WI 53706 (United States); Bednarek, Sebastian Y., E-mail: sybednar@wisc.edu [Department of Biochemistry, University of Wisconsin - Madison, 433 Babcock Dr., Madison, WI 53706 (United States)

    2010-03-19

    The Arabidopsis dynamin-related protein 1A (AtDRP1A) is involved in endocytosis and cell plate maturation in Arabidopsis. Unlike dynamin, AtDRP1A does not have any recognized membrane binding or protein-protein interaction domains. We report that GTPase active AtDRP1A purified from Escherichia coli as a fusion to maltose binding protein forms homopolymers visible by negative staining electron microscopy. These polymers interact with protein-free liposomes whose lipid composition mimics that of the inner leaflet of the Arabidopsis plasma membrane, suggesting that lipid-binding may play a role in AtDRP1A function. However, AtDRP1A polymers do not appear to assemble and disassemble in a dynamic fashion and do not have the ability to tubulate liposomes in vitro, suggesting that additional factors or modifications are necessary for AtDRP1A's in vivo function.

  11. Polymer masks for structured surface and plasma etching

    Energy Technology Data Exchange (ETDEWEB)

    Vital, Alexane [Centre de Recherche sur la Matière Divisée (CRMD), 1b rue de la Férollerie, F45071 Orléans Cedex (France); Groupe de Recherches sur l’Énergétique des Milieux Ionisés (GREMI), Polytech’Orléans, 14 rue d’Issoudun, B.P. 6744, F45067 Orléans Cedex 2 (France); Vayer, Marylène, E-mail: marylene.vayer@univ-orleans.fr [Centre de Recherche sur la Matière Divisée (CRMD), 1b rue de la Férollerie, F45071 Orléans Cedex (France); Sinturel, Christophe [Centre de Recherche sur la Matière Divisée (CRMD), 1b rue de la Férollerie, F45071 Orléans Cedex (France); Tillocher, Thomas; Lefaucheux, Philippe; Dussart, Rémi [Groupe de Recherches sur l’Énergétique des Milieux Ionisés (GREMI), Polytech’Orléans, 14 rue d’Issoudun, B.P. 6744, F45067 Orléans Cedex 2 (France)

    2015-03-30

    Graphical abstract: - Highlights: • Sub-micrometric silicon structures were prepared by cryogenic plasma etching. • Polymer templates based on phase-separated films of PS/PLA were used. • Silica structured masks were prepared by filling the polymer templates. • Etching of underlying silicon through silica templates gave original structures. - Abstract: Silica and silicon structures have been prepared at the sub-micrometer length-scale, using laterally phase-separated thin films of poly(styrene) (PS) and poly(lactic acid) (PLA) homopolymer blends. The selective removal of one polymer and the filling of the released space by silica precursor solution led, after calcination, to silica structures on silicon such as arrays of bowl-shape features or pillars, layers with through or non-through cylindrical holes, which has not been observed for some of them. The control of the morphology of the initial polymer film was a key point to achieve such type of structures. Particularly relevant was the use of solvent vapor annealing (vs thermal annealing) of the initial spin-coated films that favored and stabilized laterally phase-separated morphologies. Characteristic dimension of the domains were shown to be coupled with the thickness of the film, thinner films giving smaller domain sizes. Despite a relatively high incompatibility of the two polymers, a macro-phase separation was prevented in all the studied conditions. Sub-micrometric domains were formed, and for the thinner films, nanometric domains as small as 74 nm in size can be obtained. The silica structures formed by the infiltration of the polymer templates were used as hard masks for the cryogenic etching of underlying silicon. New structured surfaces, arrays of silicon pillars which can be plain or hollow at the upper part or arrays of cylindrical holes were formed. A selectivity as high as 21 was obtained using this type of mask for 1.5 μm deep holes having a typical diameter of 200 nm.

  12. Organometallic Polymers.

    Science.gov (United States)

    Carraher, Charles E., Jr.

    1981-01-01

    Reactions utilized to incorporate a metal-containing moiety into a polymer chain (addition, condensation, and coordination) are considered, emphasizing that these reactions also apply to smaller molecules. (JN)

  13. Polymers All Around You!

    Science.gov (United States)

    Gertz, Susan

    Background information on natural polymers, synthetic polymers, and the properties of polymers is presented as an introduction to this curriculum guide. Details are provided on the use of polymer products in consumer goods, polymer recycling, polymer densities, the making of a polymer such as GLUEP, polyvinyl alcohol, dissolving plastics, polymers…

  14. Structure, scattering patterns and phase behavior of polymer nanocomposites with nonspherical fillers

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Lisa M [ORNL; Schweizer, Kenneth S [ORNL

    2010-01-01

    Polymer nanocomposites made with carbon nanotubes, clay platelets, laponite disks and other novel nonspherical fillers have been the focus of many recent experiments. However, the effects of nanoparticle shape on statistical structure, polymer-mediated effective interactions, scattering patterns, and phase diagrams are not well understood. We extend and apply the polymer reference interaction site model liquid state theory to study the equilibrium properties of pseudo one-, two- and threedimensional particles (rod, disk, cube) of modest steric anisotropy and fixed space-filling volume in a dense adsorbing homopolymer melt up to relatively high volume fractions. The second virial coefficient, nanoparticle potential-of-mean force, osmotic compressibilities, and isotropic spinodal demixing boundaries have been determined. The entropic depletion attraction between nanoparticles is dominant for weakly adsorbing polymer, while strongly adsorbing chains induce a bridging attraction. Intermediate interfacial cohesion results in the formation of a steric stabilizing adsorbed polymer layer around each nanoparticle, which can partially damp inter-filler collective order on various length scales and increase order on an averaged length scale. The details of depletion, stabilization, or bridging behavior are shape-dependent and often, but not always, trends are monotonic with increasing filler dimensionality. Distinctive nanoparticle shape-dependent low angle features are predicted for the collective polymer structure factor associated with competing macrophase fluctuations and microphase-like ordering. The influence of nonzero mixture compressibility on the scattering profiles is established.

  15. Medium effects on minimum inhibitory concentrations of nylon-3 polymers against E. coli.

    Science.gov (United States)

    Choi, Heejun; Chakraborty, Saswata; Liu, Runhui; Gellman, Samuel H; Weisshaar, James C

    2014-01-01

    Minimum inhibitory concentrations (MICs) against E. coli were measured for three nylon-3 polymers using Luria-Bertani broth (LB), brain-heart infusion broth (BHI), and a chemically defined complete medium (EZRDM). The polymers differ in the ratio of hydrophobic to cationic subunits. The cationic homopolymer is inert against E. coli in BHI and LB, but becomes highly potent in EZRDM. A mixed hydrophobic/cationic polymer with a hydrophobic t-butylbenzoyl group at its N-terminus is effective in BHI, but becomes more effective in EZRDM. Supplementation of EZRDM with the tryptic digest of casein (often found in LB) recapitulates the LB and BHI behavior. Additional evidence suggests that polyanionic peptides present in LB and BHI may form electrostatic complexes with cationic polymers, decreasing activity by diminishing binding to the anionic lipopolysaccharide layer of E. coli. In contrast, two natural antimicrobial peptides show no medium effects. Thus, the use of a chemically defined medium helps to reveal factors that influence antimicrobial potency of cationic polymers and functional differences between these polymers and evolved antimicrobial peptides.

  16. Intrinsically Hierarchical Nanoporous Polymers via Polymerization-Induced Microphase Separation

    Energy Technology Data Exchange (ETDEWEB)

    Larsen, Michael B.; Van Horn, J. David; Wu, Fei; Hillmyer, Marc A.

    2017-05-17

    The synthesis of microporous polymers generally requires postpolymerization modification via hyper-cross-linking to trap the polymeric network in a state with high void volume. An alternative approach utilizes rigid, sterically demanding monomers to inhibit efficient packing, thus leading to a high degree of free volume between polymer side groups and main chains. Herein we combine polymers of intrinsic microporosity with polymerization-induced microphase separation (PIMS), a versatile methodology for the synthesis of nanostructured materials that can be rendered mesoporous. Copolymerization of various styrenic monomers with divinylbenzene in the presence of a poly(lactide) terminated with a chain-transfer agent (PLA-CTA) results in kinetic trapping of a microphase-separated state. Subsequent etching of PLA provides a bicontinuous mesoporous network. Using equilibrium and kinetic nitrogen sorption experiments as well as positron annihilation lifetime spectroscopy (PALS), we demonstrate that variations in the steric characteristics of the styrenic monomer impart the network with microporosity, resulting in hierarchically (meso and micro) porous materials. Additionally, structure–property relationships of the styrenic monomer with total surface area and pore volume indicate that the glass transition temperature (Tg) of the corresponding styrenic homopolymers provides a reasonable measure of the steric interactions and resultant microporosity in these systems. Finally, PALS provides insight into micro- and mesoscopic void volume differences between porous monoliths containing either tert-butyl or TMS-modified styrenic monomers compared to the parent, unmodified styrene.

  17. Degradable Polycaprolactone and Polylactide Homopolymer and Block Copolymer Brushes Prepared by Surface-Initiated Polymerization with Triazabicyclodecene and Zirconium Catalysts.

    Science.gov (United States)

    Grubbs, Joe B; Arnold, Rachelle M; Roy, Anandi; Brooks, Karson; Bilbrey, Jenna A; Gao, Jing; Locklin, Jason

    2015-09-22

    Surface-initiated ring-opening polymerization (SI-ROP) of polycaprolactone (PCL) and polylactide (PLA) polymer brushes with controlled degradation rates were prepared on oxide substrates. PCL brushes were polymerized from hydroxyl-terminated monolayers utilizing triazabicyclodecene (TBD) as the polymerization catalyst. A consistent brush thickness of 40 nm could be achieved with a reproducible unique crystalline morphology. The organocatalyzed PCL brushes were chain extended using lactide in the presence of zirconium n-butoxide to successfully grow PCL/PLA block copolymer (PCL-b-PLA) brushes with a final thickness of 55 nm. The degradation properties of "grafted from" PCL brush and the PCL-b-PLA brush were compared to "grafted to" PCL brushes, and we observed that the brush density plays a major role in degradation kinetics. Solutions of methanol/water at pH 14 were used to better solvate the brushes and increase the kinetics of degradation. This framework enables a control of degradation that allows for the precise removal of these coatings.

  18. Optimization of Organotin Polymers for Dielectric Applications.

    Science.gov (United States)

    Treich, Gregory M; Nasreen, Shamima; Mannodi Kanakkithodi, Arun; Ma, Rui; Tefferi, Mattewos; Flynn, James; Cao, Yang; Ramprasad, Rampi; Sotzing, Gregory A

    2016-08-24

    Recently, there has been a growing interest in developing wide band gap dielectric materials as the next generation insulators for capacitors, photovoltaic devices, and transistors. Organotin polyesters have shown promise as high dielectric constant, low loss, and high band gap materials. Guided by first-principles calculations from density functional theory (DFT), in line with the emerging codesign concept, the polymer poly(dimethyltin 3,3-dimethylglutarate), p(DMTDMG), was identified as a promising candidate for dielectric applications. Blends and copolymers of poly(dimethyltin suberate), p(DMTSub), and p(DMTDMG) were compared using increasing amounts of p(DMTSub) from 10% to 50% to find a balance between electronic properties and film morphology. DFT calculations were used to gain further insight into the structural and electronic differences between p(DMTSub) and p(DMTDMG). Both blend and copolymer systems showed improved results over the homopolymers with the films having dielectric constants of 6.8 and 6.7 at 10 kHz with losses of 1% and 2% for the blend and copolymer systems, respectively. The energy density of the film measured as a D-E hysteresis loop was 6 J/cc for the copolymer, showing an improvement compared to 4 J/cc for the blend. This improvement is hypothesized to come from a more uniform distribution of diacid repeat units in the copolymer compared to the blend, leading toward improved film quality and subsequently higher energy density.

  19. "Smart" Multifunctional Polymers for Enhanced Oil Recovery

    Energy Technology Data Exchange (ETDEWEB)

    Charles McCormick; Andrew Lowe

    2005-10-15

    Herein we report the synthesis and solution characterization of a novel series of AB diblock copolymers with neutral, water-soluble A blocks comprised of N,N-dimethylacrylamide (DMA) and pH-responsive B blocks of N,N-dimethylvinylbenzylamine (DMVBA). To our knowledge, this represents the first example of an acrylamido-styrenic block copolymer prepared directly in homogeneous aqueous solution. The best blocking order (using polyDMA as a macro-CTA) was shown to yield well-defined block copolymers with minimal homopolymer impurity. Reversible aggregation of these block copolymers in aqueous media was studied by {sup 1}H NMR spectroscopy and dynamic light scattering. Finally, an example of core-crosslinked micelles was demonstrated by the addition of a difunctional crosslinking agent to a micellar solution of the parent block copolymer. Our ability to form micelles directly in water that are responsive to pH represents an important milestone in developing ''smart'' multifunctional polymers that have potential for oil mobilization in Enhanced Oil Recovery Processes.

  20. Morphologies of A_2B Simple Graft Copolymer Blends: Copolymer/Copolymer and Copolymer/Homopolymer Systems to Further Elucidate the Stability of Simple Graft Phase Behavior

    Science.gov (United States)

    Lee, Chin; Pochan, Darrin; Gido, Samuel P.; Pispas, Stergios; Mays, Jimmy; Tan, Nora Beck; Trevino, Samuel

    1997-03-01

    The morphological behavior of two series of binary blends of A_2B simple graft block copolymers (A is polyisoprene and B is polystyrene) was characterized via transmission electron microscopy (TEM) and small-angle neutron scattering (SANS). Binary blends of A_2B samples with other A_2B samples of similar relative volume fractions were composed to map out the volume fraction window of stability of the randomly oriented worm phase, or ROW. This novel equilibrium phase behavior was found to occur in a neat A_2B sample with a B volume fraction of 0.81. At this unique composition the single B graft chain first becomes large enough to force the two A chains to the concave side of the AB interface in the microphase separated state. Another set of binary blends of A_2B samples was composed with the respective homopolymers in order to more rigorously determine the phase boundaries relative to volume fraction of the respective microphase separated morphologies in the A_2B systems.

  1. Antimocrobial Polymer

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, William F. (Utica, OH); Huang, Zhi-Heng (Walnut Creek, CA); Wright, Stacy C. (Columbus, GA)

    2005-09-06

    A polymeric composition having antimicrobial properties and a process for rendering the surface of a substrate antimicrobial are disclosed. The composition comprises a crosslinked chemical combination of (i) a polymer having amino group-containing side chains along a backbone forming the polymer, (ii) an antimicrobial agent selected from quaternary ammonium compounds, gentian violet compounds, substituted or unsubstituted phenols, biguanide compounds, iodine compounds, and mixtures thereof, and (iii) a crosslinking agent containing functional groups capable of reacting with the amino groups. In one embodiment, the polymer is a polyamide formed from a maleic anhydride or maleic acid ester monomer and alkylamines thereby producing a polyamide having amino substituted alkyl chains on one side of the polyamide backbone; the crosslinking agent is a phosphine having the general formula (A)3P wherein A is hydroxyalkyl; and the antimicrobial agent is chlorhexidine, dimethylchlorophenol, cetyl pyridinium chloride, gentian violet, triclosan, thymol, iodine, and mixtures thereof.

  2. Polymer inflation

    CERN Document Server

    Hassan, Syed Moeez; Seahra, Sanjeev S

    2014-01-01

    We consider the semi-classical dynamics of a free massive scalar field in a homogeneous and isotropic cosmological spacetime. The scalar field is quantized using the polymer quantization method assuming that it is described by a gaussian coherent state. For quadratic potentials, the semi-classical equations of motion yield a universe that has an early "polymer inflation" phase which is generic and almost exactly de Sitter, followed by a epoch of slow-roll inflation. We compute polymer corrections to the slow roll formalism, and discuss the probability of inflation in this model using a physical Hamiltonian arising from time gauge fixing. These results show the extent to which a quantum gravity motivated quantization method affects early universe dynamics.

  3. Healing of polymer interfaces: Interfacial dynamics, entanglements, and strength.

    Science.gov (United States)

    Ge, Ting; Robbins, Mark O; Perahia, Dvora; Grest, Gary S

    2014-07-01

    Self-healing of polymer films often takes place as the molecules diffuse across a damaged region, above their melting temperature. Using molecular dynamics simulations we probe the healing of polymer films and compare the results with those obtained for thermal welding of homopolymer slabs. These two processes differ from each other in their interfacial structure since damage leads to increased polydispersity and more short chains. A polymer sample was cut into two separate films that were then held together in the melt state. The recovery of the damaged film was followed as time elapsed and polymer molecules diffused across the interface. The mass uptake and formation of entanglements, as obtained from primitive path analysis, are extracted and correlated with the interfacial strength obtained from shear simulations. We find that the diffusion across the interface is significantly faster in the damaged film compared to welding because of the presence of short chains. Though interfacial entanglements increase more rapidly for the damaged films, a large fraction of these entanglements are near chain ends. As a result, the interfacial strength of the healing film increases more slowly than for welding. For both healing and welding, the interfacial strength saturates as the bulk entanglement density is recovered across the interface. However, the saturation strength of the damaged film is below the bulk strength for the polymer sample. At saturation, cut chains remain near the healing interface. They are less entangled and as a result they mechanically weaken the interface. Chain stiffness increases the density of entanglements, which increases the strength of the interface. Our results show that a few entanglements across the interface are sufficient to resist interfacial chain pullout and enhance the mechanical strength.

  4. Polymer electronics

    CERN Document Server

    Geoghegan, Mark

    2013-01-01

    Polymer electronics is the science behind many important new developments in technology, such as the flexible electronic display (e-ink) and many new developments in transistor technology. Solar cells, light-emitting diodes, and transistors are all areas where plastic electronics is likely to, or is already having, a serious impact on our daily lives. With polymer transistors and light-emitting diodes now being commercialised, there is a clear need for a pedagogic text thatdiscusses the subject in a clear and concise fashion suitable for senior undergraduate and graduate students. The content

  5. Temperature Dependence of Rheology and Polymer Diffusion in Silica/Polystyrene Nanocomposites

    Science.gov (United States)

    Tung, Wei-Shao; Clarke, Nigel; Composto, Russell; Meth, Jeffrey; Winey, Karen

    2015-03-01

    Time-temperature superposition using the WLF equation is well-established for both the zero shear viscosity and the polymer diffusion coefficient in homopolymer melts. This talk will present the temperature-dependence of polymer dynamics in polymer nanocomposites comprised of polystyrene and phenyl-capped silica nanoparticles (0 - 50 vol%). The WLF equation fits the temperature dependence of the tracer polymer diffusion coefficient and the fitting parameter (B/fo) decreases smoothly with nanoparticle concentration suggesting an increase in the thermal expansion coefficient for the free volume. The WLF equation also fits the temperature dependence of the zero shear viscosity from oscillatory shear experiments, although the fitting parameter (B/fo) increases substantially with nanoparticle concentration. This discrepancy between the diffusion and rheology will be discussed with respect to the reptation model, which predicts that the temperature dependence of polymer diffusion depends predominately on the temperature dependence of local viscosity, and the elastic response in nanocomposites. National Science Foundation DMR-12-10379.

  6. Antimicrobial polymers.

    Science.gov (United States)

    Jain, Anjali; Duvvuri, L Sailaja; Farah, Shady; Beyth, Nurit; Domb, Abraham J; Khan, Wahid

    2014-12-01

    Better health is basic requirement of human being, but the rapid growth of harmful pathogens and their serious health effects pose a significant challenge to modern science. Infections by pathogenic microorganisms are of great concern in many fields such as medical devices, drugs, hospital surfaces/furniture, dental restoration, surgery equipment, health care products, and hygienic applications (e.g., water purification systems, textiles, food packaging and storage, major or domestic appliances etc.) Antimicrobial polymers are the materials having the capability to kill/inhibit the growth of microbes on their surface or surrounding environment. Recently, they gained considerable interest for both academic research and industry and were found to be better than their small molecular counterparts in terms of enhanced efficacy, reduced toxicity, minimized environmental problems, resistance, and prolonged lifetime. Hence, efforts have focused on the development of antimicrobial polymers with all desired characters for optimum activity. In this Review, an overview of different antimicrobial polymers, their mechanism of action, factors affecting antimicrobial activity, and application in various fields are given. Recent advances and the current clinical status of these polymers are also discussed.

  7. Polymer physics

    CERN Document Server

    Gedde, Ulf W

    1999-01-01

    This book is the result of my teaching efforts during the last ten years at the Royal Institute of Technology. The purpose is to present the subject of polymer physics for undergraduate and graduate students, to focus the fundamental aspects of the subject and to show the link between experiments and theory. The intention is not to present a compilation of the currently available literature on the subject. Very few reference citations have thus been made. Each chapter has essentially the same structure: starling with an introduction, continuing with the actual subject, summarizing the chapter in 30D-500 words, and finally presenting problems and a list of relevant references for the reader. The solutions to the problems presented in Chapters 1-12 are given in Chapter 13. The theme of the book is essentially polymer science, with the exclusion of that part dealing directly with chemical reactions. The fundamentals in polymer science, including some basic polymer chemistry, are presented as an introduction in t...

  8. Structure-activity relationships among antifungal nylon-3 polymers: identification of materials active against drug-resistant strains of Candida albicans.

    Science.gov (United States)

    Liu, Runhui; Chen, Xinyu; Falk, Shaun P; Mowery, Brendan P; Karlsson, Amy J; Weisblum, Bernard; Palecek, Sean P; Masters, Kristyn S; Gellman, Samuel H

    2014-03-19

    Fungal infections are a major challenge to human health that is heightened by pathogen resistance to current therapeutic agents. Previously, we were inspired by host-defense peptides to develop nylon-3 polymers (poly-β-peptides) that are toxic toward the fungal pathogen Candida albicans but exert little effect on mammalian cells. Based on subsequent analysis of structure-activity relationships among antifungal nylon-3 polymers, we have now identified readily prepared cationic homopolymers active against strains of C. albicans that are resistant to the antifungal drugs fluconazole and amphotericin B. These nylon-3 polymers are nonhemolytic. In addition, we have identified cationic-hydrophobic copolymers that are highly active against a second fungal pathogen, Cryptococcus neoformans, and moderately active against a third pathogen, Aspergillus fumigatus.

  9. Ubiquitin C-terminal hydrolases cleave isopeptide- and peptide-linked ubiquitin from structured proteins but do not edit ubiquitin homopolymers

    Science.gov (United States)

    Bett, John S.; Ritorto, Maria Stella; Ewan, Richard; Jaffray, Ellis G.; Virdee, Satpal; Chin, Jason W.; Knebel, Axel; Kurz, Thimo; Trost, Matthias; Tatham, Michael H.; Hay, Ronald T.

    2014-01-01

    Modification of proteins with ubiquitin (Ub) occurs through a variety of topologically distinct Ub linkages, including Ube2W-mediated monoubiquitylation of N-terminal alpha amines to generate peptide-linked linear mono-Ub fusions. Protein ubiquitylation can be reversed by the action of deubiquitylating enzymes (DUBs), many of which show striking preference for particular Ub linkage types. Here, we have screened for DUBs that preferentially cleave N-terminal Ub from protein substrates but do not act on Ub homopolymers. We show that members of the Ub C-terminal hydrolase (UCH) family of DUBs demonstrate this preference for N-terminal deubiquitylating activity as they are capable of cleaving N-terminal Ub from SUMO2 and Ube2W, while displaying no activity against any of the eight Ub linkage types. Surprisingly, this ability to cleave Ub from SUMO2 was 100 times more efficient for UCH-L3 when we deleted the unstructured N-terminus of SUMO2, demonstrating that UCH enzymes can cleave Ub from structured proteins. However, UCH-L3 could also cleave chemically synthesized isopeptide-linked Ub from lysine 11 (K11) of SUMO2 with similar efficiency, demonstrating that UCH DUB activity is not limited to peptide-linked Ub. These findings advance our understanding of the specificity of the UCH family of DUBs, which are strongly implicated in cancer and neurodegeneration but whose substrate preference has remained unclear. In addition, our findings suggest that the reversal of Ube2W-mediated N-terminal ubiquitylation may be one physiological role of UCH DUBs in vivo. PMID:25489924

  10. Synthesis and Properties of Micron-size Magnetic Polymer Spheres with Epoxy Groups

    Institute of Scientific and Technical Information of China (English)

    刘先桥; 官月平; 邢建民; 马志亚; 刘会洲

    2003-01-01

    Micron-size superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (PSt-DVB-GMA)spheres were prepared via a modified suspension copolymerization method. Oleic acid coated magnetite (Fe3O4) nanoparticles made by co-precipitation were first mixed with monomers of St, DVB, GMA, and benzoyl peroxide (BPO) to form oil in water suspension with the presence of poly(vinyl pyrrolidone) (PVP-K30) as a stabilizer.Then the temperature of mixture was increased at a controlled rate to obtain small and relatively uniform droplets.Finally, the copolymerization reaction was initiated by the decomposition of BPO. The morphology and properties of magnetic PSt-DVB-GMA microspheres were examined by SEM, TEM, VSM, XRD and FT-IR. The magnetic microspheres obtained have very small size (about 4-7 μm) in diameter with narrow size distribution and superparamagnetic characteristics. Powder X-ray diffraction measurements show the inverse cubic spinel structure for the magnetite dispersed in polymer microspheres. FT-IR spectroscopy indicates extensive oxirane groups existed on the surface of magnetic PSt-DVB-GMA microspheres.

  11. 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.

  12. Probing the self-assembled nanostructures of functional polymers with synchrotron grazing incidence X-ray scattering.

    Science.gov (United States)

    Ree, Moonhor

    2014-05-01

    For advanced functional polymers such as biopolymers, biomimic polymers, brush polymers, star polymers, dendritic polymers, and block copolymers, information about their surface structures, morphologies, and atomic structures is essential for understanding their properties and investigating their potential applications. Grazing incidence X-ray scattering (GIXS) is established for the last 15 years as the most powerful, versatile, and nondestructive tool for determining these structural details when performed with the aid of an advanced third-generation synchrotron radiation source with high flux, high energy resolution, energy tunability, and small beam size. One particular merit of this technique is that GIXS data can be obtained facilely for material specimens of any size, type, or shape. However, GIXS data analysis requires an understanding of GIXS theory and of refraction and reflection effects, and for any given material specimen, the best methods for extracting the form factor and the structure factor from the data need to be established. GIXS theory is reviewed here from the perspective of practical GIXS measurements and quantitative data analysis. In addition, schemes are discussed for the detailed analysis of GIXS data for the various self-assembled nanostructures of functional homopolymers, brush, star, and dendritic polymers, and block copolymers. Moreover, enhancements to the GIXS technique are discussed that can significantly improve its structure analysis by using the new synchrotron radiation sources such as third-generation X-ray sources with picosecond pulses and partial coherence and fourth-generation X-ray laser sources with femtosecond pulses and full coherence.

  13. Radiation Effects on Polymers - XII

    DEFF Research Database (Denmark)

    El-Awady, N. I.; Ghanem, N. A.; Pedersen, Walther Batsberg

    1979-01-01

    Calibration of gel permeation chromatography was carried out to determine molecular weight and molecular weight distribution of the side-chains and homopolymer formed during grafting of cellulose acetate with acrylamide monomer using accelerated electrons. Polyacrylamide in side-chains and in hom...

  14. Polymer blends

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Scott D.; Naik, Sanjeev

    2017-08-22

    The present invention provides, among other things, extruded blends of aliphatic polycarbonates and polyolefins. In one aspect, provided blends comprise aliphatic polycarbonates such as poly(propylene carbonate) and a lesser amount of a crystalline or semicrystalline polymer. In certain embodiments, provided blends are characterized in that they exhibit unexpected improvements in their elongation properties. In another aspect, the invention provides methods of making such materials and applications of the materials in applications such as the manufacture of consumer packaging materials.

  15. Polymer/Solvent and Polymer/Polymer Interaction Studies

    Science.gov (United States)

    1980-09-01

    DCM and ATS are completely miscible. The sorption data described 1 2Jones, E. G., Pedrick , D. L., and Benadum, P. A., Polymer Characteri- zation Using...Encyclopedia of Polymer Science and Technology, Vol. 11, Wiley-Interscience, N.Y. (1969), p. 447. 12. Jones, E.G., Pedrick , D.L., and Benadum, P.A., Polymer

  16. Coarse-graining polymer solutions: A critical appraisal of single- and multi-site models

    Science.gov (United States)

    D'Adamo, G.; Menichetti, R.; Pelissetto, A.; Pierleoni, C.

    2015-09-01

    We critically discuss and review the general ideas behind single- and multi-site coarse-grained (CG) models as applied to macromolecular solutions in the dilute and semi-dilute regime. We first consider single-site models with zero-density and density-dependent pair potentials. We highlight advantages and limitations of each option in reproducing the thermodynamic behavior and the large-scale structure of the underlying reference model. As a case study we consider solutions of linear homopolymers in a solvent of variable quality. Secondly, we extend the discussion to multi-component systems presenting, as a test case, results for mixtures of colloids and polymers. Specifically, we found the CG model with zero-density potentials to be unable to predict fluid-fluid demixing in a reasonable range of densities for mixtures of colloids and polymers of equal size. For larger colloids, the polymer volume fractions at which phase separation occurs are largely overestimated. CG models with density-dependent potentials are somewhat less accurate than models with zero-density potentials in reproducing the thermodynamics of the system and, although they present a phase separation, they significantly underestimate the polymer volume fractions along the binodal. Finally, we discuss a general multi-site strategy, which is thermodynamically consistent and fully transferable with the number of sites, and that allows us to overcome most of the limitations discussed for single-site models.

  17. STUDY ON CASTOR OIL POLYURETHANE/POLY (METHYL METHACRYLATE) AB CROSSLINKED POLYMERS

    Institute of Scientific and Technical Information of China (English)

    DU Ying; HAN Xiaozu; LIU Wenzhong

    1991-01-01

    Castor oil polyurethane/poly(methyl methacrylate) AB crosslinked polymers (ABCP) were synthesized by free radical copolymerization of MMA and vinyl-terminated castor oil polyurethane which was obtained from isocyanate-terminated castor oil polyurethane and hydroxyethyl methacrylate.The mechanical properties, transition and relaxation, as well as compatibility and morphology of the ABCP were investigated by changing the component. The results show that the ABCP is a semicompatible system and the compatibility of the two components decreases with increasing content of the hard segment. The mechanical and damping properties of the ABCP are obviously superior to that of their homopolymers. The damping value is mainly controlled by crosslink density of the ABCP but the Tg value by component.

  18. Polymer-Chlorambucil Drug Conjugates: A Dynamic Platform of Anticancer Drug Delivery.

    Science.gov (United States)

    Saha, Biswajit; Haldar, Ujjal; De, Priyadarsi

    2016-07-01

    Recently, polymer drug conjugates (PDCs) have attracted considerable attention in the treatment of cancer. In this work, a simple strategy has been developed to make PDCs of an antitumor alkylating agent, chlorambucil, using a biocompatible disulphide linker. Chlorambucil-based chain transfer agent was used to prepare various homopolymers and block copolymers in a controlled fashion via reversible addition-fragmentation chain transfer polymerization. Chlorambucil conjugated block copolymer, poly(polyethylene glycol monomethyl ether methacrylate)-b-poly(methyl methacrylate), formed nanoaggregates in aqueous solutions, which are characterized by dynamic light scattering and field emission-scanning electron microscopy. Finally, the simplicity of the design is exemplified by performing a release study of chlorambucil under reducing condition by using D,L-dithiothreitol. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Relative stability of the FCC and HCP polymorphs with interacting polymers.

    Science.gov (United States)

    Mahynski, Nathan A; Kumar, Sanat K; Panagiotopoulos, Athanassios Z

    2015-01-14

    Recent work [Mahynski et al., Nat. Commun., 2014, 5, 4472] has demonstrated that the addition of long linear homopolymers thermodynamically biases crystallizing hard-sphere colloids to produce the hexagonal close-packed (HCP) polymorph over the closely related face-centered cubic (FCC) structure when the polymers and colloids are purely repulsive. In this report, we investigate the effects of thermal interactions on each crystal polymorph to explore the possibility of stabilizing the FCC crystal structure over the HCP. We find that the HCP polymorph remains at least as stable as its FCC counterpart across the entire range of interactions we explored, where interactions were quantified by the reduced second virial coefficient, -1.50 0, its tetrahedral voids produce a similar effect when B FCC crystals are elusive in these binary mixtures.

  20. Silicone Polymer Composites for Thermal Protection System: Fiber Reinforcements and Microstructures

    Science.gov (United States)

    2010-01-01

    R1 R3 R2 O Si R1 R2 O Si R1 R2 R3 n Homopolymer n=10,000 R1=R2= methyl , ethyl or vinyl Si R4 R4 HO O Si R5 R5 O Si R6 R6 O H n n=10,000 R4=R5=R6... methyl , ethyl , vinyl or phenyl Copolymer Figure 1. Chemical structures of ‘SM8000’ silicone polymer. 4 Journal of Composite Materials 0(0) A resin...and has been used extensively in our previous studies.29–31,34–37,41–44 The SSRM is a small-scale, liquid-fueled rocket motor burning kerosene oxygen

  1. Using surface interactions to tune adhesion and morphology in polymer systems

    Science.gov (United States)

    Asoo, Beverly Yoshiko

    Surface interactions govern physical behavior at polymer interfaces. The first part of this dissertation focuses on surface interactions and the adhesion between PET and gelatin, two surfaces that would not normally adhere with each other. However, by plasma-treating the PET, the two materials can be joined. The fracture energy of this PET/gelatin interface was measured using the asymmetric double cantilever beam (ACDB) technique and it was determined that increasing the treatment time and power of the plasma on PET increased the fracture energy of the interface. Additionally, due to the hydroscopic nature of gelatin, higher relative humidity during testing also increased the interfacial fracture energy. The second part of the dissertation examines surface interactions in polymer blends. Thermoplastic blends enjoy large-scale commercial appeal for both engineering and economic reasons. Blends can be tuned to improve various materials properties, such as elastic modulus or impact resistance. Although blends offer many advantageous benefits, the thermodynamics of these blends are not fully understood, since each particular blend has its own behavior and morphology based on processing conditions. Even more complicated morphologies could be obtained by adding filler particles. The main interest of this area of research is the formation of co-continuous morphologies by adding particles in a blend of two homopolymers. In our system, one of the homopolymers coated the particles. At very high particle concentrations, the colloidal particles facilitated the transport of aqueous solutions. This research explored the role of particle concentration in the blends, as well as the role of concentration of the homopolymer that wets the particles. In order to study the morphology and determine the percolation threshold, the resulting microstructures were imaged in real space using techniques such as transmission electron microscopy, scanning electron microscopy, and confocal

  2. "Giant surfactants" created by the fast and efficient functionalization of a DNA tetrahedron with a temperature-responsive polymer.

    Science.gov (United States)

    Wilks, Thomas R; Bath, Jonathan; de Vries, Jan Willem; Raymond, Jeffery E; Herrmann, Andreas; Turberfield, Andrew J; O'Reilly, Rachel K

    2013-10-22

    Copper catalyzed azide-alkyne cycloaddition (CuAAC) was employed to synthesize DNA block copolymers (DBCs) with a range of polymer blocks including temperature-responsive poly(N-isoproylacrylamide) (poly(NIPAM)) and highly hydrophobic poly(styrene). Exceptionally high yields were achieved at low DNA concentrations, in organic solvents, and in the absence of any solid support. The DNA segment of the DBC remained capable of sequence-specific hybridization: it was used to assemble a precisely defined nanostructure, a DNA tetrahedron, with pendant poly(NIPAM) segments. In the presence of an excess of poly(NIPAM) homopolymer, the tetrahedron-poly(NIPAM) conjugate nucleated the formation of large, well-defined nanoparticles at 40 °C, a temperature at which the homopolymer precipitated from solution. These composite nanoparticles were observed by dynamic light scattering and cryoTEM, and their hybrid nature was confirmed by AFM imaging. As a result of the large effective surface area of the tetrahedron, only very low concentrations of the conjugate were required in order for this surfactant-like behavior to be observed.

  3. Near-edge X-ray absorption fine-structure spectroscopy of naphthalene diimide-thiophene co-polymers

    Energy Technology Data Exchange (ETDEWEB)

    Gann, Eliot; McNeill, Christopher R., E-mail: christopher.mcneill@monash.edu [Department of Materials Engineering, Monash University, Wellington Road, Clayton, Victoria 3800 (Australia); Szumilo, Monika; Sirringhaus, Henning [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Sommer, Michael [Institute of Macromolecular Chemistry, University of Freiburg, Stefan-Meier-Str. 31, 79104 Freiburg (Germany); Maniam, Subashani; Langford, Steven J. [School of Chemistry, Monash University, Wellington Road, Clayton, Victoria 3800 (Australia); Thomsen, Lars [Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168 (Australia)

    2014-04-28

    Near-edge X-ray absorption fine-structure (NEXAFS) spectroscopy is an important tool for probing the structure of conjugated polymer films used in organic electronic devices. High-performance conjugated polymers are often donor-acceptor co-polymers which feature a repeat unit with multiple functional groups. To facilitate better application of NEXAFS spectroscopy to the study of such materials, improved understanding of the observed NEXAFS spectral features is required. In order to examine how the NEXAFS spectrum of a donor-acceptor co-polymer relates to the properties of the sub-units, a series of naphthalene diimide-thiophene-based co-polymers have been studied where the nature and length of the donor co-monomer has been systematically varied. The spectra of these materials are compared with that of a thiophene homopolymer and naphthalene diimide monomer enabling peak assignment and the influence of inter-unit electronic coupling to be assessed. We find that while it is possible to attribute peaks within the π* manifold as arising primarily due to the naphthalene diimide or thiophene sub-units, very similar dichroism of these peaks is observed indicating that it may not be possible to separately probe the molecular orientation of the separate sub-units with carbon K-edge NEXAFS spectroscopy.

  4. Solubilities of crystalline drugs in polymers: an improved analytical method and comparison of solubilities of indomethacin and nifedipine in PVP, PVP/VA, and PVAc.

    Science.gov (United States)

    Sun, Ye; Tao, Jing; Zhang, Geoff G Z; Yu, Lian

    2010-09-01

    A previous method for measuring solubilities of crystalline drugs in polymers has been improved to enable longer equilibration and used to survey the solubilities of indomethacin (IMC) and nifedipine (NIF) in two homo-polymers [polyvinyl pyrrolidone (PVP) and polyvinyl acetate (PVAc)] and their co-polymer (PVP/VA). These data are important for understanding the stability of amorphous drug-polymer dispersions, a strategy actively explored for delivering poorly soluble drugs. Measuring solubilities in polymers is difficult because their high viscosities impede the attainment of solubility equilibrium. In this method, a drug-polymer mixture prepared by cryo-milling is annealed at different temperatures and analyzed by differential scanning calorimetry to determine whether undissolved crystals remain and thus the upper and lower bounds of the equilibrium solution temperature. The new annealing method yielded results consistent with those obtained with the previous scanning method at relatively high temperatures, but revised slightly the previous results at lower temperatures. It also lowered the temperature of measurement closer to the glass transition temperature. For D-mannitol and IMC dissolving in PVP, the polymer's molecular weight has little effect on the weight-based solubility. For IMC and NIF, the dissolving powers of the polymers follow the order PVP > PVP/VA > PVAc. In each polymer studied, NIF is less soluble than IMC. The activities of IMC and NIF dissolved in various polymers are reasonably well fitted to the Flory-Huggins model, yielding the relevant drug-polymer interaction parameters. The new annealing method yields more accurate data than the previous scanning method when solubility equilibrium is slow to achieve. In practice, these two methods can be combined for efficiency. The measured solubilities are not readily anticipated, which underscores the importance of accurate experimental data for developing predictive models.

  5. Electrospraying and Electrospinning of Polymers for Biomedical Applications. Poly(Lactic-Co-Glycolic Acid) and Poly(Ethylene-Co-Vinylacetate). Appendix 2

    Science.gov (United States)

    Stitzel, Joel D.; Bowlin, Gary L.; Mansfield, Kevin; Wnek, Gary E.; Simpson, David G.

    2000-01-01

    Significant opportunities exist for the processing of polymers (homopolymers and blends) using electric fields. Specific attention is given here to electrospinning, but we note that electroaerosol formation and field-modulated film casting represent additional processing options. Of particular interest is the ability to generate polymer fibers of sub-micron dimensions using electrospinning, down to about 0.05 microns (50 nm), a size range that has been traditionally difficult to access. In our work, poly(lactic-co-glycolic acid), PLA/PGA, poly(lactic acid) PLA, and poly(ethylene-co-vinylacetate) (PEVA) have been deposited from solutions in methylene chloride or chloroform by electrospraying or electrospinning to afford morphologically tailored materials for tissue engineering and related applications. Low solution concentrations tend to favor electrostatic spraying ('electro-aerosolization') while higher concentrations lead to spinning on fibrous mats. Preliminary observations of muscle cell growth on PLA electrospun mats are reported.

  6. Shape memory polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Thomas S.; Bearinger, Jane P.

    2017-08-29

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  7. Shape memory polymers

    Science.gov (United States)

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  8. Polymer compatibility in two dimensions. Modeling of phase behavior of mixed polymethacrylate Langmuir films.

    Science.gov (United States)

    Bernardini, C; Stuart, M A Cohen; Stoyanov, S D; Arnaudov, L N; Leermakers, F A M

    2012-04-03

    We analyze the possibility of polymer blends undergoing phase separation in two dimensions. To this end, we investigate a model system consisting of water-supported Langmuir monolayers, obtained from binary polyalkyl-methacrylate mixtures (PXMA, where X stands for any of the type of ester side groups used: M, methyl-; E, ethyl-; B, butyl-; H, hexyl-; O, octyl-; L, lauryl-methacrylate), by means of self consistent field (SCF) calculations. In particular, we address the conditions which determine demixing and phase separation in the two-dimensional system, showing that a sufficient chain length mismatch in the ester side group moieties is able to drive the polymer demixing. When the difference in length of the alkyl chain of the ester moieties on the two types of polymers is progressively reduced, from 11 carbon atoms (PMMA/PLMA) to 4 carbons only (POMA/PLMA), the demixing tendency is also reduced. The polymer/subphase interactions affect more the distribution of the polymer coils in the POMA/PLMA blend monolayer. Mixing of the two polymers is observed, but also a partial layering along the vertical direction. We also add, to a PMMA/PLMA blended monolayer, a third component, namely, a symmetrical diblock copolymer of the type PLMA-b-PMMA. We observe adsorption of the diblock copolymer exclusively at the contact line between the two homopolymer domains, and a concomitant lowering of the line tension. The line tension varies with the chemical potential of the diblock copolymer according to Gibbs' law, which demonstrates that PLMA-b-PMMA can act as a "lineactant" (the equivalent of a surfactant in two-dimensional systems) in the binary demixed PMMA/PLMA Langmuir monolayer.

  9. Effects of molecular architecture on fluid ingress behavior of glassy polymer networks

    Science.gov (United States)

    Jaskson, Matthew Blaine

    This manuscript demonstrates the synthesis of glassy polymer network isomers to control morphological variations and study solvent ingress behavior independent of chemical affinity. Well-controlled network architectures with varying free volume average hole-sizes have been shown to substantially influence solvent ingress within glassy polymer networks. Bisphenol-A diglycidyl ether (DGEBA), bisphenol-F diglycidyl ether (DGEBF), Triglycidyl p-aminophenol (pAP, MY0510), Triglycidyl maminophenol (mAP, MY0610), and tetraglydicyl-4,4'-diamino-diphenyl methane (TGDDM, MY721) were cured with 3,3'- and 4,4'-diaminodiphenyl sulfone (DDS) at a stoichiometric ratio of 1:1 oxirane to amine active hydrogen to generate a series of network architectures with an average free volume hole-size (Vh) ranging between 54-82 A3. Polymer networks were exposed to water and a broad range of organic solvents ranging in van der Waals (vdW) volumes from 18-88 A3 for up to 10,000h time. A clear relationship between glassy polymer network Vh and fluid penetration has been established. As penetrant vdW volume approached Vh, uptake kinetics significantly decreased, and as penetrant vdW volume exceeded Vh, a blocking mechanism dominated ingress and prevented penetrant transport. These results suggest that reducing the free volume hole-size is a reasonable approach to control solvent properties for glassy polymer networks. New techniques to monitor and predict the diffusion behavior of liquids through glassy networks are also presented. Digital Image Correlation (DIC) was employed to accurately measure the strain developed during case II diffusion. This technique also presented a new theory for a relationship between sample topology and irreversible macroscopic brittle failure induced by solvent absorption. A new modeling technique has been developed which can accurately predict the chemical and physical interactions a solvent may have with a glassy network. This new model can be used as a

  10. Enzyme-catalyzed degradation of biodegradable polymers derived from trimethylene carbonate and glycolide by lipases from Candida antarctica and Hog pancreas.

    Science.gov (United States)

    Liu, Feng; Yang, Jian; Fan, Zhongyong; Li, Suming; Kasperczyk, Janusz; Dobrzynski, Piotr

    2012-01-01

    Enzyme-catalyzed degradation of poly(trimethylene carbonate) homo-polymer (PTMC) and poly(trimethylene carbonate-co-glycolide) co-polymer (PTGA) was investigated in the presence of lipases from Candida antarctica and Hog pancreas. Degradation was monitored by gravimetry, size-exclusion chromatography (SEC), nuclear magnetic resonance (NMR), tensiometry and environmental scanning electron microscopy (ESEM). PTMC can be rapidly degraded by Candida antarctica lipase with 98% mass loss after 9 days, while degradation by Hog pancreas lipase leads to 27% mass loss. Introduction of 16% glycolide units in PTMC chains strongly affects the enzymatic degradation. Hog pancreas lipase becomes more effective to PTGA co-polymer with a mass loss of 58% after 9 days, while Candida antarctica lipase seems not able to degrade PTGA. Bimodal molecular weight distributions are observed during enzymatic degradation of both PTMC and PTGA, which can be assigned to the fact that the surface is largely degraded while the internal part remains intact. The composition of the PTGA co-polymer remains constant, and ESEM shows that the polymers are homogeneously eroded during enzymatic degradation. Contact angle measurements confirm the enzymatic degradation mechanism, i.e., enzyme adsorption on the polymer surface followed by enzyme-catalyzed chain cleavage.

  11. Polymer nanocomposites: polymer and particle dynamics

    KAUST Repository

    Kim, Daniel

    2012-01-01

    Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has been hypothesized that these unusual properties result from fast diffusion of the nanostructures in the host polymer, which facilitates polymer chain relaxation by constraint release and other processes. In this study, the effects of addition of sterically stabilized inorganic nanoparticles to entangled cis-1,4-polyisoprene and polydimethylsiloxane on the overall rheology of nanocomposites are discussed. In addition, insights about the relaxation of the host polymer chains and transport properties of nanoparticles in entangled polymer nanocomposites are presented. The nanoparticles are found to act as effective plasticizers for their entangled linear hosts, and below a critical, chemistry and molecular-weight dependent particle volume fraction, lead to reduced viscosity, glass transition temperature, number of entanglements, and polymer relaxation time. We also find that the particle motions in the polymer host are hyperdiffusive and at the nanoparticle length scale, the polymer host acts like a simple, ideal fluid and the composites\\' viscosity rises with increasing particle concentration. © 2012 The Royal Society of Chemistry.

  12. New polyoxometalates containing hybrid polymers and their potential for nano-patterning.

    Science.gov (United States)

    Kalyani, Vishwanath; Satyanarayana, V S V; Singh, Vikram; Pradeep, Chullikkattil P; Ghosh, Subrata; Sharma, Satinder K; Gonsalves, Kenneth E

    2015-01-26

    Two new polyoxometalate (POM)-based hybrid monomers (Bu4 N)5 (H)[P2 V3 W15 O59 {(OCH2 )3 CNHCO(CH3 )CCH2 }] (2) and (S(CH3 )2 C6 H4 OCOC(CH3 )=CH2 )6 [PV  2Mo10 O40 ] (5) were developed by grafting polymerizable organic units covalently or electrostatically onto Wells-Dawson and Keggin-type clusters and were characterized by analytical and spectroscopic techniques including ESI-MS and/or single-crystal X-ray diffraction analyses. Radical initiated polymerization of 2 and 5 with organic monomers (methacryloyloxy)phenyldimethylsulfonium triflate (MAPDST) and/or methylmethacrylate (MMA) yielded a new series of POM/polymer hybrids that were characterized by (1) H, (31) P NMR and IR spectroscopic techniques, gel-permeation chromatography as well as thermal analyses. Preliminary tests were conducted on these POM/polymer hybrids to evaluate their properties as photoresists using electron beam (E-beam)/extreme ultraviolet (EUV) lithographic techniques. It was observed that the POM/polymer hybrid of 2 with MAPDST exhibited improved sensitivity under EUV lithographic conditions in comparison to the MAPDST homopolymer resist possibly due to the efficient photon harvesting by the POM clusters from the EUV source.

  13. Demixing by a Nematic Mean Field: Coarse-Grained Simulations of Liquid Crystalline Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Ramírez-Hernández, Abelardo; Hur, Su-Mi; Armas-Pérez, Julio; Cruz, Monica; de Pablo, Juan

    2017-03-01

    Liquid crystalline polymers exhibit a particular richness of behaviors that stems from their rigidity and their macromolecular nature. On the one hand, the orientational interaction between liquid-crystalline motifs promotes their alignment, thereby leading to the emergence of nematic phases. On the other hand, the large number of configurations associated with polymer chains favors formation of isotropic phases, with chain stiffness becoming the factor that tips the balance. In this work, a soft coarse-grained model is introduced to explore the interplay of chain stiffness, molecular weight and orientational coupling, and their role on the isotropic-nematic transition in homopolymer melts. We also study the structure of polymer mixtures composed of stiff and flexible polymeric molecules. We consider the effects of blend composition, persistence length, molecular weight and orientational coupling strength on the melt structure at the nano-and mesoscopic levels. Conditions are found where the systems separate into two phases, one isotropic and the other nematic. We confirm the existence of non-equilibrium states that exhibit sought-after percolating nematic domains, which are of interest for applications in organic photovoltaic and electronic devices.

  14. Polymer-mediated nanorod self-assembly predicted by dissipative particle dynamics simulations.

    Science.gov (United States)

    Khani, Shaghayegh; Jamali, Safa; Boromand, Arman; Hore, Michael J A; Maia, Joao

    2015-09-14

    Self-assembly of nanoparticles in polymer matrices is an interesting and growing subject in the field of nanoscience and technology. We report herein on modelling studies of the self-assembly and phase behavior of nanorods in a homopolymer matrix, with the specific goal of evaluating the role of deterministic entropic and enthalpic factors that control the aggregation/dispersion in such systems. Grafting polymer brushes from the nanorods is one approach to control/impact their self-assembly capabilities within a polymer matrix. From an energetic point of view, miscible interactions between the brush and the matrix are required for achieving a better dispersibility; however, grafting density and brush length are the two important parameters in dictating the morphology. Unlike in previous computational studies, the present Dissipative Particle Dynamics (DPD) simulation framework is able to both predict dispersion or aggregation of nanorods and determine the self-assembled structure, allowing for the determination of a phase diagram, which takes all of these factors into account. Three types of morphologies are predicted: dispersion, aggregation and partial aggregation. Moreover, favorable enthalpic interactions between the brush and the matrix are found to be essential for expanding the window for achieving a well-dispersed morphology. A three-dimensional phase diagram is mapped on which all the afore-mentioned parameters are taken into account. Additionally, in the case of immiscibility between brushes and the matrix, simulations predict the formation of some new and tunable structures.

  15. Structural correlations in the generation of polaron pairs in low-bandgap polymers for photovoltaics

    Science.gov (United States)

    Tautz, Raphael; da Como, Enrico; Limmer, Thomas; Feldmann, Jochen; Egelhaaf, Hans-Joachim; von Hauff, Elizabeth; Lemaur, Vincent; Beljonne, David; Yilmaz, Seyfullah; Dumsch, Ines; Allard, Sybille; Scherf, Ullrich

    2012-07-01

    Polymeric semiconductors are materials where unique optical and electronic properties often originate from a tailored chemical structure. This allows for synthesizing conjugated macromolecules with ad hoc functionalities for organic electronics. In photovoltaics, donor-acceptor co-polymers, with moieties of different electron affinity alternating on the chain, have attracted considerable interest. The low bandgap offers optimal light-harvesting characteristics and has inspired work towards record power conversion efficiencies. Here we show for the first time how the chemical structure of donor and acceptor moieties controls the photogeneration of polaron pairs. We show that co-polymers with strong acceptors show large yields of polaron pair formation up to 24% of the initial photoexcitations as compared with a homopolymer (η=8%). π-conjugated spacers, separating the donor and acceptor centre of masses, have the beneficial role of increasing the recombination time. The results provide useful input into the understanding of polaron pair photogeneration in low-bandgap co-polymers for photovoltaics.

  16. ROMP- and RAFT-Based Guanidinium-Containing Polymers as Scaffolds for Protein Mimic Synthesis.

    Science.gov (United States)

    Sarapas, Joel M; Backlund, Coralie M; deRonde, Brittany M; Minter, Lisa M; Tew, Gregory N

    2017-05-17

    Cell-penetrating peptides are an important class of molecules with promising applications in bioactive cargo delivery. A diverse series of guanidinium-containing polymeric cell-penetrating peptide mimics (CPPMs) with varying backbone chemistries was synthesized and assessed for delivery of both GFP and fluorescently tagged siRNA. Specifically, we examined CPPMs based on norbornene, methacrylate, and styrene backbones to determine how backbone structure impacted internalization of these two cargoes. Either charge content or degree of polymerization was held constant at 20, with diguanidinium norbornene molecules being polymerized to both 10 and 20 repeat units. Generally, homopolymer CPPMs delivered low amounts of siRNA into Jurkat T cells, with no apparent backbone dependence; however, by adding a short hydrophobic methyl methacrylate block to the guanidinium-rich methacrylate polymer, siRNA delivery to nearly the entire cell population was achieved. Protein internalization yielded similar results for most of the CPPMs, though the block polymer was unable to deliver proteins. In contrast, the styrene-based CPPM yielded the highest internalization for GFP (≈40 % of cells affected), showing that indeed backbone chemistry impacts protein delivery, specifically through the incorporation of an aromatic group. These results demonstrate that an understanding of how polymer structure affects cargo-dependent internalization is critical to designing new, more effective CPPMs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Methacrylate-based monolithic layers for planar chromatography of polymers.

    Science.gov (United States)

    Maksimova, E F; Vlakh, E G; Tennikova, T B

    2011-04-29

    A series of macroporous monolithic methacrylate-based materials was synthesized by in situ free radical UV-initiated copolymerization of functional monomers, such as glycidyl methacrylate (GMA), butyl methacrylate (BuMA), 2-aminoethyl methacrylate (AEMA), 2-hydroxyethyl methacrylate (HEMA) and 2-cyanoethyl methacrylate (CEMA), with crosslinking agent, namely, ethylene glycol dimethacrylate (EDMA). The materials obtained were applied as the stationary phases in simple and robust technique - planar chromatography (PLC). The method of separation layer fabrication representing macroporous polymer monolith bound to the specially prepared glass surface was developed and optimized. The GMA-EDMA and BuMA-EDMA matrixes were successfully applied for the separation of low molecular weight compounds (the mixture of several dies), as well as poly(vinylpyrrolidone) and polystyrene homopolymers of different molecular weights using reversed-phase mechanism. The materials based on copolymers AEMA-HEMA-EDMA and CEMA-HEMA-EDMA were used for normal-phase PLC separation of 2,4-dinitrophenyl amino acids and polystyrene standards.

  18. Using artificial intelligence methods to design new conducting polymers

    Directory of Open Access Journals (Sweden)

    Ronaldo Giro

    2003-12-01

    Full Text Available In the last years the possibility of creating new conducting polymers exploring the concept of copolymerization (different structural monomeric units has attracted much attention from experimental and theoretical points of view. Due to the rich carbon reactivity an almost infinite number of new structures is possible and the procedure of trial and error has been the rule. In this work we have used a methodology able of generating new structures with pre-specified properties. It combines the use of negative factor counting (NFC technique with artificial intelligence methods (genetic algorithms - GAs. We present the results for a case study for poly(phenylenesulfide phenyleneamine (PPSA, a copolymer formed by combination of homopolymers: polyaniline (PANI and polyphenylenesulfide (PPS. The methodology was successfully applied to the problem of obtaining binary up to quinternary disordered polymeric alloys with a pre-specific gap value or exhibiting metallic properties. It is completely general and can be in principle adapted to the design of new classes of materials with pre-specified properties.

  19. Tailoring the color of electrochromic polymer devices by stoichiometric control of blends and copolymers

    Science.gov (United States)

    Meeker, David Lloyd

    A systematic study of the color and optical properties of electrochromic devices using stoichiometric combinations of polymer blends and copolymers is presented. Monomers of N-phenyl-2-(5/sp /prime-vinyl-2/sp /prime- thienyl)-5-(2/prime'-thienyl)-pyrrole (SNPhS) and N-vinyl carbazole (NVC) are combined into two forms: homopolymer blends, and copolymers. The homopolymers poly N-phenyl-2-(5 /sp /prime-vinyl-2 /sp/prime-thienyl)- 5-(2 /prime'-thienyl)-pyrrole (PSNPhS) and poly (N-vinylcarbazole) (PVK) were blended together according to the stoichiometric mass ratios (1:4), (3:2) and (4:1) of (PSNPhS:PVK) respectively. Copolymers were prepared using feed stock ratios identical to the polymer blends, which produced the respective stoichiometric ratios (3:7), (3:2) and (7:3) of (PSNPhS:PVK). Photoluminescence (PL) and photoluminescence excitation spectroscopy (PLE) allowed the identification of excimer formation in dilute solutions of the blends and copolymers. Two excimer emission bands at 373 nm and 420 nm in were attributed to poly(N-vinyl carbazole), in the partial overlap and sandwich configuration. Analysis of the PL data indicated that the effects of these excimers on the color of the electrochromic devices was minimized by avoiding (1:1) stoichiometric combinations of PVK and PSNPhS. Films of the polymeric materials were characterized by optical absorption, and spectroelectrochemistry. Solid state devices were assembled and their spectrocolorimetery measurements correlated with the stoichiometric ratios of copolymers and polymer blends. Analysis using Commission International de l'Eclairage (CIE) L*a*b* color coordinates determined that stoichiometric adjustment of polymer blends and copolymers yields a strong correlation (R2 = 0.99) with the amount of SNPhS present in the device. It was found that blends access the widest range of color adjustments, while copolymers provide the most precise means of tailoring color over a narrow range.

  20. MOLECULAR IMPRINTED POLYMERS--Novel Polymer Adsorbents

    Institute of Scientific and Technical Information of China (English)

    LI Haitao; XU Mancai; SHI Zuoqing; HE Binglin

    2001-01-01

    Molecular imprinted polymers (MIPs) are novel functional polymer materials and known as specific adsorbents for the template molecules. These novel functional polymers have promised potential applications in racemic resolution, sensor, chromatography, adsorptive separation and other fields. This review exhibits the approach for preparing MIPs, the features of MIPs obtained by different routes and the characteristics of adsorptive separations with MIPs. The molecular recognition mechanism and the idea of the present possibilities and limitations of molecular imprinting polymerization are discussed as well.

  1. Conducting polymer materials

    Directory of Open Access Journals (Sweden)

    Jovanović Slobodan M.

    2003-01-01

    Full Text Available Conducting polymers represent a very interesting group of polymer materials Investigation of the synthesis, structure and properties of these materials has been the subject of considerable research efforts in the last twenty years. A short presentating of newer results obtained by investigating of the synthesis, structure and properties of two basic groups of conducting polymers: a conducting polymers the conductivity of which is the result of their molecular structure, and b conducting polymer composites (EPC, is given in this paper. The applications and future development of this group of polymer materials is also discussed.

  2. In Vitro and in Vivo Evaluation of Novel Cross-Linked Saccharide Based Polymers as Bile Acid Sequestrants

    Directory of Open Access Journals (Sweden)

    Francisco Javier Lopez-Jaramillo

    2015-02-01

    Full Text Available Bile acid sequestrants (BAS represent a therapeutic approach for the management of hypercholesterolemia that relies on the cationic polymeric nature of BAS to selectively bind negatively charged bile acids. We hypothesized that the cross-linking of β-cyclodextrin (β-CD and saccharides such as starch or dextrin with divinyl sulfone (DVS yields homo- and hetero-polymeric materials with the ability to trap sterols. Our hypothesis was put to test by synthesizing a library of 22 polymers that were screened to evaluate their capability to sequester both cholesterol (CHOL and cholic and deoxycholic acids (CA and DCA. Three polymers synthesized in high yield were identified as promising. Two were neutral hetero-polymers of β-CD and starch or dextrin and the third was a weakly cationic homo-polymer of starch, highlighting the importance of the cavity effect. They were tested in hypercholesterolemic male Wistar rats and their ability to regulate hypercholesterolemia was similar to that for the reference BAS cholestyramine, but with two additional advantages: (i they normalized the TG level and (ii they did not increase the creatinine level. Neither hepatotoxicity nor kidney injury was detected, further supporting them as therapeutical candidates to manage hypercholesterolemia.

  3. Tuning the Mechanical Properties of Polymer Nanocomposites Filled with Grafted Nanoparticles by Varying the Grafted Chain Length and Flexibility

    Directory of Open Access Journals (Sweden)

    Zixuan Wang

    2016-08-01

    Full Text Available By employing coarse-grained molecular dynamics simulation, we simulate the spatial organization of the polymer-grafted nanoparticles (NPs in homopolymer matrix and the resulting mechanical performance, by particularly regulating the grafted chain length and flexibility. The morphologies ranging from the agglomerate, cylinder, sheet, and string to full dispersion are observed, by gradually increasing the grafted chain length. The radial distribution function and the total interaction energy between NPs are calculated. Meanwhile, the stress–strain behavior of each morphology and the morphological evolution during the uniaxial tension are simulated. In particular, the sheet structure exhibits the best mechanical reinforcement compared to other morphologies. In addition, the change of the grafted chain flexibility to semi-flexibility leads to the variation of the morphology. We also find that at long grafted chain length, the stress–strain behavior of the system with the semi-flexible grafted chain begins to exceed that of the system with the flexible grafted chain, attributed to the physical inter-locking interaction between the matrix and grafted polymer chains. A similar transition trend is as well found in the presence of the interfacial chemical couplings between grafted and matrix polymer chains. In general, this work is expected to help to design and fabricate high performance polymer nanocomposites filled with grafted NPs with excellent and controllable mechanical properties.

  4. Poly(cyclohexadiene)-Based Polymer Electrolyte Membranes for Fuel Cell Applications

    Energy Technology Data Exchange (ETDEWEB)

    Mays, Jimmy W.

    2011-03-07

    The goal of this research project was to create and develop fuel cell membranes having high proton conductivity at high temperatures and high chemical and mechanical durability. Poly(1,3-cyclohexadiene) (PCHD) is of interest as an alternative polymer electrolyte membrane (PEM) material due to its ring-like structure which is expected to impart superior mechanical and thermal properties, and due to the fact that PCHD can readily be incorporated into a range of homopolymer and copolymer structures. PCHD can be aromatized, sulfonated, or fluorinated, allowing for tuning of key performance structure and properties. These factors include good proton transport, hydrophilicity, permeability (including fuel gas impermeability), good mechanical properties, morphology, thermal stability, crystallinity, and cost. The basic building block, 1,3-cyclohexadiene, is a hydrocarbon monomer that could be inexpensively produced on a commercial scale (pricing typical of other hydrocarbon monomers). Optimal material properties will result in novel low cost PEM membranes engineered for high conductivity at elevated temperatures and low relative humidities, as well as good performance and durability. The primary objectives of this project were: (1) To design, synthesize and characterize new non-Nafion PEM materials that conduct protons at low (25-50%) RH and at temperatures ranging from room temperature to 120 C; and (2) To achieve these objectives, a range of homopolymer and copolymer materials incorporating poly(cyclohexadiene) (PCHD) will be synthesized, derivatized, and characterized. These two objectives have been achieved. Sulfonated and crosslinked PCHD homopolymer membranes exhibit proton conductivities similar to Nafion in the mid-RH range, are superior to Nafion at higher RH, but are poorer than Nafion at RH < 50%. Thus to further improve proton conductivity, particularly at low RH, poly(ethylene glycol) (PEG) was incorporated into the membrane by blending and by

  5. Phosphorylcholine substituted polyolefins: New syntheses, solution assemblies, and polymer vesicles

    Science.gov (United States)

    Kratz, Katrina A.

    This thesis describes the synthesis and applications of a new series of amphiphilic homopolymers and copolymers consisting of hydrophobic polyolefin backbone and hydrophilic phosphorylcholine (PC) pendant groups. These polymers are synthesized by ring opening metathesis polymerization (ROMP) of a novel PC- cyclooctene monomer, and copolymerization of various functionalized cyclooctene comonomers. Incorporation of different comonomers into the PC-polyolefin backbone affords copolymers with different functionalities, including crosslinkers, fluorophores, and other reactive groups, that tune the range of applications of these polymers, and their hydrophobic/hydrophilic balance. The amphiphilic nature of PC-polyolefins was exploited in oil-water interfacial assembly, providing robust polymer capsules to encapsulate and deliver nanoparticles to damaged regions of a substrate in a project termed `repair-and-go.' In repair-and-go, a flexible microcapsule filled with a solution of nanoparticles probes an imperfection-riddled substrate as it rolls over the surface. The thin capsule wall allows the nanoparticles to escape the capsules and enter into the cracks, driven in part by favorable interactions between the nanoparticle ligands and the cracked surface (i.e., hydrophobic-hydrophobic interactions). The capsules then continue their transport along the surface, filling more cracks and depositing particles into them. The amphiphilic nature of PC-polyolefins was also exploited in aqueous assembly, forming novel polymer vesicles in water. PC-polyolefin vesicles ranged in size from 50 nm to 30 µm. The mechanical properties of PC-polyolefin vesicles were measured by micropipette aspiration techniques, and found to be more robust than conventional liposomes or polymersomes prepared from block copolymers. PC-polyolefin vesicles have potential use in drug delivery; it was found that the cancer drug doxorubicin could be encapsulated efficiently in PC-polyolefin vesicles. In

  6. 40 CFR 721.5600 - Substituted oxirane.

    Science.gov (United States)

    2010-07-01

    ... when the written program and MSDS are not required under § 721.72 (a) and (c), respectively. The provisions of § 721.72(g) requiring placement of specific information on a label and MSDS do not apply when a label and MSDS are not required under § 721.72 (b) and (c), respectively. (iii) Industrial, commercial...

  7. Phosphoric acid-doped poly(1-vinyl-1,2,4-triazole) as water-free proton conducting polymer electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Celik, Sevim Ue.; Aslan, Ayse; Bozkurt, Ayhan [Department of Chemistry, Fatih University, 34500 Bueyuekcekmece-Istanbul (Turkey)

    2008-08-15

    The development of anhydrous proton conducting membrane is important for the operation of polymer electrolyte membrane fuel cell (PEMFC) at intermediate temperature (100-200 C). In the present work, poly(1-vinyl-1,2,4-triazole), PVTri was produced by free radical polymerization of 1-vinyl-1,2,4-triazole with a high yield. The molecular weight of the homopolymer was measured via gel permeation chromatography (GPC) and M{sub w} was found to be 104,216 g/mol. The structure of the homopolymer was proved by solid state {sup 13}C CP-MAS NMR spectroscopy. The polymer was doped with phosphoric acid at various molar ratios x = 1 and x = 2. The proton transfer from H{sub 3}PO{sub 4} to the triazole rings was proved with Fourier-transform infrared spectroscopy (FT-IR). Thermogravimetry (TG) analysis showed that the samples are thermally stable up to approximately 250 C. Differential scanning calorimetry (DSC) results illustrated the homogeneity of the materials as well as the plasticizing effect of the dopant. The electrochemical stability of the materials was studied by cyclic voltammetry (CV). The proton conductivity of these materials increased with dopant concentration and the temperature. In the anhydrous state, the proton conductivity of PVTri 1 H{sub 3}PO{sub 4} is 5 x 10{sup -} {sup 3} S/cm at 150 C and the conductivity of PVTri 2 H{sub 3}PO{sub 4} was 4 x 10{sup -} {sup 3} S/cm at 140 C. (author)

  8. 4',6-diamidino-2-phenylindole (DAPI) interacts with rare structures of GC polymers.

    Science.gov (United States)

    Barcellona, M L; Chen, Y; Müller, J D; Gratton, E

    2001-01-01

    The binding of 4',6-diamidino-2-phenylindole (DAPI) to double-stranded GC polymers either in the alternating or in homopolymer sequence was investigated using fluorescence techniques. We employed fluctuation correlation spectroscopy, which measures the diffusion coefficient of fluorescent particles, to demonstrate that the fluorescence was originating from relatively slowly diffusing entities. These entities display a very large heterogeneity of diffusing coefficients, indicating that molecular aggregation is extensive in our samples. We used frequency domain fluorometry to characterize the fluorescence lifetime of the species, while varying the GC polymer-dye coverage systematically. At very low coverage we observed a relatively bright fluorescent component with a lifetime value of approximately 4 ns. The stoichiometry of binding of this bright species was such that it can only arise from rare molecular structures, either unusual loops or large molecular aggregates. The amount and characteristics of this bright fluorescent component were different between the homo and the alternating polymer, indicating that the difference in sequence of the two polymers is responsible for the different aggregates which are then detected in the fluorescence experiment. At large GC polymer coverage we observed a relatively wide distribution of fluorescent species with short lifetime values, in the range between 0.12 and 0.2 ns. Given the stoichiometry of binding of this fluorescent component, we concluded that it could arise either from intercalative and/or non-specific binding to the DNA double-stranded molecules. We comment on the origin of the rare but brightly fluorescent binding sites and discuss the potential to detect such unusual DNA structures.

  9. Polymer Fluid Dynamics.

    Science.gov (United States)

    Bird, R. Byron

    1980-01-01

    Problems in polymer fluid dynamics are described, including development of constitutive equations, rheometry, kinetic theory, flow visualization, heat transfer studies, flows with phase change, two-phase flow, polymer unit operations, and drag reduction. (JN)

  10. Polymer composites containing nanotubes

    Science.gov (United States)

    Bley, Richard A. (Inventor)

    2008-01-01

    The present invention relates to polymer composite materials containing carbon nanotubes, particularly to those containing singled-walled nanotubes. The invention provides a polymer composite comprising one or more base polymers, one or more functionalized m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers and carbon nanotubes. The invention also relates to functionalized m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers, particularly to m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers having side chain functionalization, and more particularly to m-phenylenevinylene-2,5-disubstituted-p-phenylenevinylene polymers having olefin side chains and alkyl epoxy side chains. The invention further relates to methods of making polymer composites comprising carbon nanotubes.

  11. Introduction to Polymer Chemistry.

    Science.gov (United States)

    Harris, Frank W.

    1981-01-01

    Reviews the physical and chemical properties of polymers and the two major methods of polymer synthesis: addition (chain, chain-growth, or chain-reaction), and condensation (step-growth or step-reaction) polymerization. (JN)

  12. Dendritic polyurea polymers.

    Science.gov (United States)

    Tuerp, David; Bruchmann, Bernd

    2015-01-01

    Dendritic polymers, subsuming dendrimers as well as hyperbranched or highly branched polymers are well established in the field of polymer chemistry. This review article focuses on urea based dendritic polymers and summarizes their synthetic routes through both isocyanate and isocyanate-free processes. Furthermore, this article highlights applications where dendritic polyureas show their specific chemical and physical potential. For these purposes scientific publications as well as patent literature are investigated to generate a comprehensive overview on this topic.

  13. Antimicrobial Modifications of Polymers

    OpenAIRE

    Sedlarik, Vladimir

    2013-01-01

    This chapter is focused on antimicrobial modifications of polymer materials intended for medical devices production. Firstly, a brief introduction into the field of medical application of polymers is presented. Considering the fact that polymer medical devices are often connected with occurrence of nosocomial infections, the next part refers to this phenomenon and its causes. One of the possibilities of reducing of the infection occurrence is aimed at polymer modification. It is a key topic o...

  14. Engineered Protein Polymers

    Science.gov (United States)

    2010-05-31

    of each pure polymer, we plan to combine the various polymer solutions in different ratios to tune the composition and physico-chemical properties...protein materials as vehicles for storage and delivery of small molecules. Each protein polymer under concentrations for particle formation ( vida

  15. Dynamic covalent polymers

    NARCIS (Netherlands)

    Garcia Melo, Fatima; Smulders, Maarten M.J.

    2016-01-01

    This Highlight presents an overview of the rapidly growing field of dynamic covalent polymers. This class of polymers combines intrinsic reversibility with the robustness of covalent bonds, thus enabling formation of mechanically stable, polymer-based materials that are responsive to external

  16. Going beyond the classical amphiphilicity paradigm: the self-assembly of completely hydrophobic polymers into free-standing sheets and hollow nanostructures in solvents of variable quality.

    Science.gov (United States)

    Huang, Huanting; Liao, Yin; Bu, Weifeng; Wang, Wenjie; Sun, Jing Zhi

    2016-06-14

    Self-assembly is well-known to occur in amphiphiles, and the totally hydrophobic ones are never reported to self-assemble. In this work we report for the first time that the latter can self-assemble into free-standing sheets and hollow spheres in toluene/methanol mixed solvents by modulating the solvent quality. The homopolymers studied in this work are polystyrene (PS), polyphenylacetylene (PPA), and poly(3-hexyl thiophene) (P3HT), representing polymers with different rigidity. All the three form a homogenous solution in toluene, but self-assembly occurs in the toluene/methanol mixed solvents. Micrometer sized free-standing sheets were formed for PS, PPA, and P3HT at methanol volume fractions being 43%, 50%, and 67%, respectively, and hollow spheres were observed for PPA at higher methanol fractions of 75 and 90%. Under the latter solvent conditions, PS forms solid spheres, yet ill-defined aggregates and free-standing sheets coexist in the case of P3HT. This non-solvent induced self-assembly was explained by a delicate balance of two "opposing forces": van der Waals attractive and entropic repulsive forces generated between the segments of these homopolymers within a single chain, between two chains, and among more chains in the solvents of worsened quality.

  17. 一种新型高吸水性树脂的合成及吸液性能%SYNTHESIS AND SWELLING PROPERTIES OF NOVEL SUPERABSORBENT POLYMER

    Institute of Scientific and Technical Information of China (English)

    刘洋; 谢建军; 张新颖

    2003-01-01

    @@ 1 INTRODUCTION Superabsorbent polymers(SAPs)are new functional materials,which can absorb and retain an unusually large amount of water and body fluid.They have a variety of valuable applications[1,2] because of their unique characteristics,and they can be divided into two classes:nonionic and ionic polymers.The majority of present-day SAPs are prepared from acrylic acid[1-4],as ionic polymers, whose absorbing rate is slow and resistance to metal ion is weak[5]. However, as a nonionic polymer, the absorption capacity of the homopolymer of acrylamide (AM) is low, but it has quick swelling rate and strong resistance to metal ion.Recently researchers were focused on polymerizing acrylamide with ionic monomers to improve its resistance to metal ion[6,7].Some superabsorbent polymers that can absorb both water and pure alcohol were also reported in recent years[8], but their absorbency in pure alcohol is less than 100 g*g-1,much smaller than their water-absorbency.

  18. The Influence of Polymer Sequence on the Formation of Bulk-Heterojunctions in Organic Solar Cells

    Science.gov (United States)

    Gao, Dong

    This thesis summarizes my work on organic solar cells during my graduate studies. Chapter 1 serves as an introduction to organic solar cells. I will briefly discuss the working mechanism, and describe the device fabrication processes and testing set up that I designed at the beginning of my graduate studies. Chapter 2 describes the size-dependent behavior of polymer solar cells measured under partial illumination. We found that ITO resistance is a significant source of power loss because sheet resistance (Rs) increases with area. The non-illuminated part of a partially illuminated device introduces some interesting effects related to the physics of device operation. Specifically, this contributes additional "dark diodes" that connect in parallel with an illuminated cell, giving rise to an apparent decrease in VOC and increase in FF as the illuminated portion of the cell is decreased. Chapter 3 is a study of a P3HS-b-P3HT block copolymer as a donor material in organic solar cells. Fiber-like nanostructures are formed spontaneously in P3HS-b-P3HT:PCBM devices, and their thermal stability exceeds homopolymer:PCBM devices or ternary mixtures. Although P3HS-b-P3HT contains two distinct electron donor materials, the EQE spectra, hole mobility, Jsc, and PCE exceed that of a physical mixture of the two homopolymers and PCBM. Chapter 4 compares the photovoltaic properties of two conjugated copolymers with the same composition, P3HS-b-P3HT and P3HS- s-P3HT. The block polymer spontaneously undergoes intrinsic phase separation and the statistical polymer does not. P3HS-b-P3HT devices perform best when the native self-assembled structure is most perturbed, which is accomplished using PC71BM. P3HS-s-P3HT is a polymer that does not form a native phase separated structure. Here vapor annealing can be used to more predictably optimize the polymer:fullerene morphology. Chapter 5 studies the evolution of the electron mobility of two different acceptors with different crystallinity

  19. Fire-safe polymers and polymer composites

    Science.gov (United States)

    Zhang, Huiqing

    The intrinsic relationships between polymer structure, composition and fire behavior have been explored to develop new fire-safe polymeric materials. Different experimental techniques, especially three milligram-scale methods---pyrolysis-combustion flow calorimetry (PCFC), simultaneous thermal analysis (STA) and pyrolysis GC/MS---have been combined to fully characterize the thermal decomposition and flammability of polymers and polymer composites. Thermal stability, mass loss rate, char yield and properties of decomposition volatiles were found to be the most important parameters in determining polymer flammability. Most polymers decompose by either an unzipping or a random chain scission mechanism with an endothermic decomposition of 100--900 J/g. Aromatic or heteroaromatic rings, conjugated double or triple bonds and heteroatoms such as halogens, N, O, S, P and Si are the basic structural units for fire-resistant polymers. The flammability of polymers can also be successfully estimated by combining pyrolysis GC/MS results or chemical structures with TGA results. The thermal decomposition and flammability of two groups of inherently fire-resistant polymers---poly(hydroxyamide) (PHA) and its derivatives, and bisphenol C (BPC II) polyarylates---have been systematically studied. PHA and most of its derivatives have extremely low heat release rates and very high char yields upon combustion. PHA and its halogen derivatives can completely cyclize into quasi-polybenzoxazole (PBO) structures at low temperatures. However, the methoxy and phosphate derivatives show a very different behavior during decomposition and combustion. Molecular modeling shows that the formation of an enol intermediate is the rate-determining step in the thermal cyclization of PHA. BPC II-polyarylate is another extremely flame-resistant polymer. It can be used as an efficient flame-retardant agent in copolymers and blends. From PCFC results, the total heat of combustion of these copolymers or blends

  20. Nanoporous polymer electrolyte

    Science.gov (United States)

    Elliott, Brian [Wheat Ridge, CO; Nguyen, Vinh [Wheat Ridge, CO

    2012-04-24

    A nanoporous polymer electrolyte and methods for making the polymer electrolyte are disclosed. The polymer electrolyte comprises a crosslinked self-assembly of a polymerizable salt surfactant, wherein the crosslinked self-assembly includes nanopores and wherein the crosslinked self-assembly has a conductivity of at least 1.0.times.10.sup.-6 S/cm at 25.degree. C. The method of making a polymer electrolyte comprises providing a polymerizable salt surfactant. The method further comprises crosslinking the polymerizable salt surfactant to form a nanoporous polymer electrolyte.

  1. Biostable glucose permeable polymer

    DEFF Research Database (Denmark)

    2017-01-01

    A new biostable glucose permeable polymer has been developed which is useful, for example, in implantable glucose sensors. This biostable glucose permeable polymer has a number of advantageous characteristics and, for example, does not undergo hydrolytic cleavage and degradation, thereby providing...... a composition that facilitates long term sensor stability in vivo. The versatile characteristics of this polymer allow it to be used in a variety of contexts, for example to form the body of an implantable glucose sensor. The invention includes the polymer composition, sensor systems formed from this polymer...

  2. Polymer material biodegradation

    Directory of Open Access Journals (Sweden)

    B. Grabowska

    2010-04-01

    Full Text Available Data from literature was used to discuss the impact of external factors (stress, radiation, temperature, ultrasounds, biological organisms on the course of polymer material degradation. Polymer materials, in widespread use for over a dozen years, constitute a serious environmental problem. This is why their susceptibility to biodegradation is researched. Work on biodegradable polymers concernsmodifying their structure to bring their physical and chemical properties closer to plastics in practical use or using biodegradable polymers as an alternative for the current conventional materials. In addition, the publication also presents the first results of work on the biodegradation of polymer foundry binders.

  3. Polymer friction Molecular Dynamics

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, Vladimir N.; Persson, Bo N. J.

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: a) polymer sliding against a hard substrate, and b) polymer sliding on polymer. In the first setup the shear stresses are relatively...... independent of molecular length. For polymer sliding on polymer the friction is significantly larger, and dependent on the molecular chain length. In both cases, the shear stresses are proportional to the squeezing pressure and finite at zero load, indicating an adhesional contribution to the friction force....

  4. Advanced polymers in medicine

    CERN Document Server

    Puoci, Francesco

    2014-01-01

    The book provides an up-to-date overview of the diverse medical applications of advanced polymers. The book opens by presenting important background information on polymer chemistry and physicochemical characterization of polymers. This serves as essential scientific support for the subsequent chapters, each of which is devoted to the applications of polymers in a particular medical specialty. The coverage is broad, encompassing orthopedics, ophthalmology, tissue engineering, surgery, dentistry, oncology, drug delivery, nephrology, wound dressing and healing, and cardiology. The development of polymers that enhance the biocompatibility of blood-contacting medical devices and the incorporation of polymers within biosensors are also addressed. This book is an excellent guide to the recent advances in polymeric biomaterials and bridges the gap between the research literature and standard textbooks on the applications of polymers in medicine.

  5. Dispersion of iron oxide particles in industrial waters. The influence of polymer structure, ionic charge, and molecular weight

    Energy Technology Data Exchange (ETDEWEB)

    Amjad, Z. [Goodrich (B.F.) Co., Brecksville, OH (United States)

    1999-01-01

    This paper deals with studies on the influence of polymeric and non-polymeric materials on the dispersion of iron oxide particles in aqueous system. The aim of the work was to evaluate the performance of a variety of additives as iron oxide dispersants. The polymers investigated include homopolymers of acrylamide, vinylpyrrolidone, actylic acid, maleic acid, 2-acrylamido-2-methylpropane sulfonic acid, and acrylic acid based copolymers containing a variety of functional groups. It has been found that the addition of low levels of copolymers to the iron oxide suspension has a marked effect in dispersing iron oxide particles. The dispersancy data of several polymers indicate that the performance of the polymer depends upon the functional group, molecular weight, composition, and the ionic charge of the polymer. The results on non-polymeric materials such as polyphosphates, phosphonates, and surfactants show that these additives, compared to copolymers are ineffective as iron oxide dispersants. (orig.) [Deutsch] In dieser Arbeit wird der Einfluss von polymeren und nichtpolymeren Stoffen auf die Dispergierung von Eisenoxidpartikeln in waessrigen Systemen untersucht. Ziel dieser Arbeit war es, die Wirkung verschiedener Additive als Eisenoxiddispergatoren zu bewerten. Die untersuchten Polymere waren homopolymeres Acrylamid, Vinylpyrrolidon, Acrylsaeure, Maleinsaeure, 2-Acrylamido-2-Methylpropansulfonsaeure und Copolymere auf Acrylsaeurebasis mit verschiedenen fuktionellen Gruppen. Die Zugabe von geringen Mengen Copolymeren zur Eisenoxidsuspension hat einen deutlichen Einfluss auf die Dispergierung dieser Partikel. Die Daten zum Dispergierverhalten einiger Polymere zeigen, dass die Wirkung eines Polymers von der fuktionellen Gruppe, dem Molgewicht, der Zusammensetzung und der Ionenladung des Polymers abhaengt. Ergebnisse, die mit nichtpolymeren Substanzen wie Polyphosphaten, Phosphonaten und Tensiden erhalten wurden, zeigen, dass sich diese Additive nicht so gut als

  6. POLYMER-CLAY NANOCOMPOSITES: CHEMICAL GRAFTING OF POLYSTYRENE ONTO CLOISITE 20A

    Institute of Scientific and Technical Information of China (English)

    Yagoub Mansoori; Khadijeh Roojaei; Mohammad Reza Zamanloo; Gholamhassan Imanzadeh

    2012-01-01

    An account of the experiments on preparing polystyrene (PS) nanocomposites through grafting the polymer onto organophilic montmorillonite is reported.Cloisite 20A was reacted with vinyltrichlorosilane to replace the edge hydroxyl groups of the clay with a vinyl moiety.Because the reaction may liberate HCl,it was performed in the presence of sodium hydrogencarbonate to prevent the exchange of quaternary alkylammonium cations with H+ ions.Only the silanol groups on the edge of the clay react with vinyltrichlorosilane.The radical polymerization of the product with styrene as a vinyl monomer leads to chemical grafting of PS onto the montmorillonite surface.The homopolymer formed during polymerization was separated from the grafted organoclay by Soxhlet extraction.Chemical grafting of the polymer onto Cloisite 20A was confirmed by infrared spectroscopy.The prepared nanocomposite materials and the grafted nano-particles were studied by XRD.Exfoliated nanocomposites may be obtained for 0.5 wt%-1 wt% clay content.The nanocomposites were studied by thermogravimertic analysis (TGA) dynamic thermal analysis (DTA) and dynamic mechanical analysis (DMTA).

  7. Phase transitions of a single polymer chain: A Wang-Landau simulation study.

    Science.gov (United States)

    Taylor, Mark P; Paul, Wolfgang; Binder, Kurt

    2009-09-21

    A single flexible homopolymer chain can assume a variety of conformations which can be broadly classified as expanded coil, collapsed globule, and compact crystallite. Here we study transitions between these conformational states for an interaction-site polymer chain comprised of N=128 square-well-sphere monomers with hard-sphere diameter sigma and square-well diameter lambdasigma. Wang-Landau sampling with bond-rebridging Monte Carlo moves is used to compute the density of states for this chain and both canonical and microcanonical analyses are used to identify and characterize phase transitions in this finite size system. The temperature-interaction range (i.e., T-lambda) phase diagram is constructed for lambda1.06 these two states are separated by an intervening collapsed globule phase and thus, with decreasing temperature a chain undergoes a continuous coil-globule (collapse) transition followed by a discontinuous globule-crystal (freezing) transition. For well diameters lambdamodel, that a collapsed globule state is unstable with respect to a solid phase for flexible polymers with sufficiently short-range monomer-monomer interactions.

  8. Preparation and characterization of branched polymers as postoperative anti-adhesion barriers

    Science.gov (United States)

    Way, Tzong-Der; Hsieh, Shih-Rong; Chang, Chi-Jung; Hung, Tsung-Wei; Chiu, Chun-Hwei

    2010-03-01

    Homopolymers and copolymers synthesized from biocompatible monomers with polyethylene glycol (PEG) and polycaprolactone side chains, were applied to separate healing tissues and prevent postsurgical adhesions. The results of the contact angle and the ESCA spectra reveal the presence of more PEG segments on the surface of the PEMC1 film than the P(EM) 3(EMC4) 1 film. The effects of the molecular structures on the surface properties, including the wetting properties and the anti-tissue adhesion behaviors, of the films were examined. Fluorescent polymer was fixed on the surface of the film to form the marking dot. The in vivo degradation behaviors of the surface-marked films were investigated non-invasively by monitoring the location of the fluorescent signal. The degradation behaviors of various films observed in the animal study were consistent with those observed by in vivo imaging. Proper arrangement of PEG segments on the polymer side chain helped to keep a large proportion of PEG segments close to the surface of the film. Such an arrangement represents an effective means of preventing postoperative tissue adhesion.

  9. How osmolytes influence hydrophobic polymer conformations: A unified view from experiment and theory.

    Science.gov (United States)

    Mondal, Jagannath; Halverson, Duncan; Li, Isaac T S; Stirnemann, Guillaume; Walker, Gilbert C; Berne, Bruce J

    2015-07-28

    It is currently the consensus belief that protective osmolytes such as trimethylamine N-oxide (TMAO) favor protein folding by being excluded from the vicinity of a protein, whereas denaturing osmolytes such as urea lead to protein unfolding by strongly binding to the surface. Despite there being consensus on how TMAO and urea affect proteins as a whole, very little is known as to their effects on the individual mechanisms responsible for protein structure formation, especially hydrophobic association. In the present study, we use single-molecule atomic force microscopy and molecular dynamics simulations to investigate the effects of TMAO and urea on the unfolding of the hydrophobic homopolymer polystyrene. Incorporated with interfacial energy measurements, our results show that TMAO and urea act on polystyrene as a protectant and a denaturant, respectively, while complying with Tanford-Wyman preferential binding theory. We provide a molecular explanation suggesting that TMAO molecules have a greater thermodynamic binding affinity with the collapsed conformation of polystyrene than with the extended conformation, while the reverse is true for urea molecules. Results presented here from both experiment and simulation are in line with earlier predictions on a model Lennard-Jones polymer while also demonstrating the distinction in the mechanism of osmolyte action between protein and hydrophobic polymer. This marks, to our knowledge, the first experimental observation of TMAO-induced hydrophobic collapse in a ternary aqueous system.

  10. Preparation and Chemical Properties of π-Conjugated Polymers Containing Indigo Unit in the Main Chain

    Directory of Open Access Journals (Sweden)

    Hiroki Fukumoto

    2014-03-01

    Full Text Available π-Conjugated polymers based on indigo unit were prepared. Dehalogenative polycondensation of N-hexyl-6,6'-dibromoindigo with a zerovalent nickel complex gave a homopolymer, P(HexI, in 77% yield. Copolymer of N-hexyl-indigo and pyridine, P(HexI-Py, was also prepared in 50% yield. P(HexI showed good solubility in organic solvents, whereas P(HexI-Py was only soluble in acids such as HCOOH. The weight-average molecular weights (Mw of P(HexI and P(HexI-Py were determined to be 10,000 and 40,000, respectively, by a light scattering method. Pd-catalyzed polycondensation between 6,6'-dibromoindigo with N-BOC (BOC = t-butoxycarbonyl substituents and a diboronic compound of 9,9-dioctylfluorene afforded the corresponding alternating copolymer, P(BOCI-Flu, as a deep red solid in 98% yield. P(BOCI-Flu was soluble in N-methyl-2-pyrroridone and showed an Mw of 29,000 in GPC analysis. Treatment of P(BOCI-Flu with CF3COOH smoothly led to a BOC-deprotection reaction to give an insoluble deep green polymer, P(I-Flu, in a quantitative yield. Diffuse reflectance spectra of powdery P(BOCI-Flu and P(I-Flu showed peaks at about 580 nm and 630 nm, respectively, which are thought to originate from the indigo unit.

  11. Modulation of graft architectures for enhancing hydrophobic interaction of biomolecules with thermoresponsive polymer-grafted surfaces.

    Science.gov (United States)

    Idota, Naokazu; Kikuchi, Akihiko; Kobayashi, Jun; Sakai, Kiyotaka; Okano, Teruo

    2012-11-01

    This paper describes the effects of graft architecture of poly(N-isopropylacrylamide) (PIPAAm) brush surfaces on thermoresponsive aqueous wettability changes and the temperature-dependent hydrophobic interaction of steroids in silica capillaries (I.D.: 50 μm). PIPAAm brushes were grafted onto glass substrates by surface-initiated atom transfer radical polymerization (ATRP) that is one of the living radical polymerization techniques. Increases in the graft density and chain length of PIPAAm brushes increased the hydration of polymer brushes, resulting in the increased hydrophilic properties of the surface below the transition temperature of PIPAAm at 32 °C. More hydrophobic surface properties were also observed on surfaces modified with the block copolymers of IPAAm and n-butyl methacrylate (BMA) than that with IPAAm homopolymer-grafted surfaces over the transition temperature. Using PBMA-b-PIPAAm-grafted silica capillaries, the baseline separation of steroids was successfully achieved by only changing temperature. The incorporation of hydrophobic PBMA chains in grafted PIPAAm enhanced the hydrophobic interaction with testosterone above the transition temperature. The surface modification of hydrophobicity-enhanced thermoresponsive polymers is a promising method for the preparation of thermoresponsive biointerfaces that can effectively modulated their biomolecule and cell adsorption with the wide dynamic range of hydrophilic/hydrophobic property change across the transition temperature.

  12. Synthesis and characterization of hydrogels from 1-vinylimidazole. Highly resistant co-polymers with synergistic effect

    Energy Technology Data Exchange (ETDEWEB)

    Primo, Gastón A.; Garcia Manzano, María F.; Romero, Marcelo R.; Alvarez Igarzabal, Cecilia I., E-mail: cia@fcq.unc.edu.ar

    2015-03-01

    Monomers N, N-(dimethyl) amine ethyl methacrylate (DMAEMT) and N-[3 - (dimethylamine) propyl] methacrylamide (DMAPMD) were co-polymerized with 1-vinylimidazole (VI) in different proportions and crosslinked with N,N′-methylenebisacrylamide (BIS) in aqueous phase, to yield highly resistant hydrogels. The polymeric products were studied by swelling kinetics, solvent diffusion within the crosslinked network, thermal decomposition, infrared spectroscopy (FTIR), variable pressure scanning electron microscopy (VP-SEM), and mechanical and rheological tests. The incorporation of VI in the polymerization reaction led to beneficial changes in the properties of the final materials such as improvement in the resistance of the materials and increase in the percentage of deformation capable of withstanding elongation before breaking. All VI-containing products were mechanically strong with respect to homo-polymers (DMAPMD 100% and DMAEMT 100%). The most resistant products were DMAPMD-co-VI 60% and DMAEMT-co-VI 60%. A synergistic effect with the addition of VI is revealed by Young’s modulus that increases 5 and 10 times regarding the hydrogels yielded from pure monomers, respectively. - Highlights: • Highly resistant materials with improved mechanical properties can be obtained by adding 1-vinylimidazole as co-polymer. • A synergistic effect can be observed by the combination of hydrophilic and hydrophobic monomers. • The mechanical and swelling properties of different materials obtained were determined.

  13. Structure of binary mixed polymer Langmuir layers

    NARCIS (Netherlands)

    Bernardini, C.

    2012-01-01

    The possibility of preparing 2D stable emulsions through mixing of homopolymers in a Langmuir monolayer is the core topic of this thesis. While colloid science has achieved well established results in the study of bulk dispersed systems, accounts on properties of mixed monomolecular films are fewer,

  14. Structure of binary mixed polymer Langmuir layers

    NARCIS (Netherlands)

    Bernardini, C.

    2012-01-01

    The possibility of preparing 2D stable emulsions through mixing of homopolymers in a Langmuir monolayer is the core topic of this thesis. While colloid science has achieved well established results in the study of bulk dispersed systems, accounts on properties of mixed monomolecular films are fewer,

  15. Polymer dynamics from synthetic polymers to proteins

    Indian Academy of Sciences (India)

    D Richter; R Biehl; M Monkenbush; B Hoffmann; R Merkel

    2008-10-01

    Starting from the standard model of polymer motion - the Rouse model - we briefly present some key experimental results on the mesoscopic dynamics of polymer systems. We touch the role of topological confinement as expressed in the reptation model and discuss in some more detail processes limiting the confinement. In the second part we relate to some new developments concerning the measurement of large-scale internal dynamics of proteins by neutron spin echo.

  16. Star-Branched Polymers (Star Polymers)

    KAUST Repository

    Hirao, Akira

    2015-09-01

    The synthesis of well-defined regular and asymmetric mixed arm (hereinafter miktoarm) star-branched polymers by the living anionic polymerization is reviewed in this chapter. In particular, much attention is being devoted to the synthetic development of miktoarm star polymers since 2000. At the present time, the almost all types of multiarmed and multicomponent miktoarm star polymers have become feasible by using recently developed iterative strategy. For example, the following well-defined stars have been successfully synthesized: 3-arm ABC, 4-arm ABCD, 5-arm ABCDE, 6-arm ABCDEF, 7-arm ABCDEFG, 6-arm ABC, 9-arm ABC, 12-arm ABC, 13-arm ABCD, 9-arm AB, 17-arm AB, 33-arm AB, 7-arm ABC, 15-arm ABCD, and 31-arm ABCDE miktoarm star polymers, most of which are quite new and difficult to synthesize by the end of the 1990s. Several new specialty functional star polymers composed of vinyl polymer segments and rigid rodlike poly(acetylene) arms, helical polypeptide, or helical poly(hexyl isocyanate) arms are introduced.

  17. Directed Self-Assembly of Block Copolymers for High Breakdown Strength Polymer Film Capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Samant, Saumil P.; Grabowski, Christopher A.; Kisslinger, Kim; Yager, Kevin G.; Yuan, Guangcui; Satija, Sushil K.; Durstock, Michael F.; Raghavan, Dharmaraj; Karim, Alamgir

    2016-03-04

    Emerging needs for fast charge/discharge yet high-power, lightweight, and flexible electronics requires the use of polymer-film-based solid-state capacitors with high energy densities. Fast charge/discharge rates of film capacitors on the order of microseconds are not achievable with slower charging conventional batteries, supercapacitors and related hybrid technologies. However, the current energy densities of polymer film capacitors fall short of rising demand, and could be significantly enhanced by increasing the breakdown strength (EBD) and dielectric permittivity (εr) of the polymer films. Co-extruded two-homopolymer component multilayered films have demonstrated much promise in this regard showing higher EBD over that of component polymers. Multilayered films can also help incorporate functional features besides energy storage, such as enhanced optical, mechanical, thermal and barrier properties. In this work, we report accomplishing multilayer, multicomponent block copolymer dielectric films (BCDF) with soft-shear driven highly oriented self-assembled lamellar diblock copolymers (BCP) as a novel application of this important class of self-assembling materials. Results of a model PS-b-PMMA system show ~50% enhancement in EBD of self-assembled multilayer lamellar BCP films compared to unordered as-cast films, indicating that the breakdown is highly sensitive to the nanostructure of the BCP. The enhancement in EBD is attributed to the “barrier effect”, where the multiple interfaces between the lamellae block components act as barriers to the dielectric breakdown through the film. The increase in EBD corresponds to more than doubling the energy storage capacity using a straightforward directed self-assembly strategy. This approach opens a new nanomaterial paradigm for designing high energy density dielectric materials.

  18. CO2 -Responsive polymers.

    Science.gov (United States)

    Lin, Shaojian; Theato, Patrick

    2013-07-25

    This Review focuses on the recent progress in the area of CO2 -responsive polymers and provides detailed descriptions of these existing examples. CO2 -responsive polymers can be categorized into three types based on their CO2 -responsive groups: amidine, amine, and carboxyl groups. Compared with traditional temperature, pH, or light stimuli-responsive polymers, CO2 -responsive polymers provide the advantage to use CO2 as a "green" trigger as well as to capture CO2 directly from air. In addition, the current challenges of CO2 -responsive polymers are discussed and the different solution methods are compared. Noteworthy, CO2 -responsive polymers are considered to have a prosperous future in various scientific areas.

  19. BSA Hybrid Synthesized Polymer

    Institute of Scientific and Technical Information of China (English)

    Zong Bin LIU; Xiao Pei DENG; Chang Sheng ZHAO

    2006-01-01

    Bovine serum albumin (BSA), a naturally occurring biopolymer, was regarded as a polymeric material to graft to an acrylic acid (AA)-N-vinyl pyrrolidone (NVP) copolymer to form a biomacromolecular hybrid polymer. The hybrid polymer can be blended with polyethersulfone (PES) to increase the hydrophilicity of the PES membrane, which suggested that the hybrid polymer might have a wide application in the modification of biomaterials.

  20. Triclosan antimicrobial polymers

    OpenAIRE

    Petersen, Richard C.

    2016-01-01

    Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are ...

  1. Thermally conductive polymers

    Science.gov (United States)

    Byrd, N. R.; Jenkins, R. K.; Lister, J. L. (Inventor)

    1971-01-01

    A thermally conductive polymer is provided having physical and chemical properties suited to use as a medium for potting electrical components. The polymer is prepared from hydroquinone, phenol, and formaldehyde, by conventional procedures employed for the preparation of phenol-formaldehyde resins. While the proportions of the monomers can be varied, a preferred polymer is formed from the monomers in a 1:1:2.4 molar or ratio of hydroquinone:phenol:formaldehyde.

  2. Polymer material biodegradation

    OpenAIRE

    B. Grabowska

    2010-01-01

    Data from literature was used to discuss the impact of external factors (stress, radiation, temperature, ultrasounds, biological organisms) on the course of polymer material degradation. Polymer materials, in widespread use for over a dozen years, constitute a serious environmental problem. This is why their susceptibility to biodegradation is researched. Work on biodegradable polymers concernsmodifying their structure to bring their physical and chemical properties closer to plastics in prac...

  3. Characterisation of polymers, 1

    CERN Document Server

    Crompton, Roy

    2008-01-01

    This essential guide to Polymer Characterisation is a complete compendium of methodologies that have evolved for the determination of the chemical composition of polymers. This 478-page book gives an up-to-date and thorough exposition of the state-of-the-art theories and availability of instrumentation needed to effect chemical and physical analysis of polymers. This is supported by approximately 1200 references. Volume 1 covers the methodology used for the determination of metals, non-metals and organic functional groups in polymers, and for the determination of the ratio in which different m

  4. Biopolymers Versus Synthetic Polymers

    Directory of Open Access Journals (Sweden)

    Florentina Adriana Cziple

    2008-10-01

    Full Text Available This paper present an overview of important synthetic and natural polymers with emphasis on polymer structure, the chemistry of polymer formation. an introduction to polymer characterization. The biodegradation process can take place aerobically and anaerobically with or without the presence of light. These factors allow for biodegradation even in landfill conditions which are normally inconducive to any degradation. The sheeting used to make these packages differs significantly from other “degradable plastics” in the market as it does not attempt to replace the current popular materials but instead enhances them by rendering them biodegradable.

  5. The importance of chain connectivity in the formation of non-covalent interactions between polymers and single-walled carbon nanotubes and its impact on dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Sumpter, Bobby G [ORNL; Dadmun, Mark D [ORNL; Driva, Paraskevi [ORNL; Ivanov, Ilia N [ORNL; Geohegan, David B [ORNL; Linton, Dias [ORNL; Feigerle, Charles S [ORNL

    2010-01-01

    In this study we investigate the formation of non-covalent electron donor acceptor (EDA) interactions between polymers and single-walled carbon nanotubes (SWNTs) with the goal of optimizing interfacial adhesion and homogeneity of nanocomposites without modifying the SWNT native surface. Nanocomposites of SWNTs and three sets of polymer matrices with varying composition of electron donating 2-(dimethylamino)ethyl methacrylate (DMAEMA) or electron accepting acrylonitrile (AN) and cyanostyrene (CNSt) were prepared, quantitatively characterized by optical microscopy and Raman spectroscopy (Raman mapping, Raman D* peak shifts) and qualitatively compared through thick film composite visualization. The experimental data show that copolymers with 30 mol% DMAEMA, 45 mol% AN, 23 mol% CNSt and polyacrylonitrile homopolymer have the highest extent of intermolecular interaction, which translates to an optimum SWNT spatial dispersion among the series. These results are found to correlate very well with the intermolecular interaction energies obtained from quantum density functional theory calculations. Both experimental and computational results also illustrate that chain connectivity is critical in controlling the accessibility of the functional groups to form intermolecular interactions. This means that an adequate distance between interacting functional groups on a polymer chain is needed in order to allow efficient intermolecular contact. Thus, controlling the amount of electron donating or withdrawing moieties throughout the polymer chain will direct the extent of EDA interaction, which enables tuning the SWNT dispersion.

  6. The importance of chain connectivity in the formation of non-covalent interactions between polymers and single-walled carbon nanotubes and its impact on dispersion

    Energy Technology Data Exchange (ETDEWEB)

    Linton, Dias [ORNL; Driva, Paraskevi [ORNL; Ivanov, Ilia N [ORNL; Geohegan, David B [ORNL; Feigerle, Charles S [ORNL; Dadmun, Mark D [ORNL

    2010-05-01

    In this study we investigate the formation of non-covalent electron donor acceptor (EDA) interactions between polymers and single-walled carbon nanotubes (SWNTs) with the goal of optimizing interfacial adhesion and homogeneity of nanocomposites without modifying the SWNT native surface. Nanocomposites of SWNTs and three sets of polymer matrices with varying composition of electron donating 2-(dimethylamino)ethyl methacrylate (DMAEMA) or electron accepting acrylonitrile (AN) and cyanostyrene (CNSt) were prepared, quantitatively characterized by optical microscopy and Raman spectroscopy (Raman mapping, Raman D* peak shifts) and qualitatively compared through thick film composite visualization. The experimental data show that copolymers with 30 mol% DMAEMA, 45 mol% AN, 23 mol% CNSt and polyacrylonitrile homopolymer have the highest extent of intermolecular interaction, which translates to an optimum SWNT spatial dispersion among the series. These results are found to correlate very well with the intermolecular interaction energies obtained from quantum density functional theory calculations. Both experimental and computational results also illustrate that chain connectivity is critical in controlling the accessibility of the functional groups to form intermolecular interactions. This means that an adequate distance between interacting functional groups on a polymer chain is needed in order to allow efficient intermolecular contact. Thus, controlling the amount of electron donating or withdrawing moieties throughout the polymer chain will direct the extent of EDA interaction, which enables tuning the SWNT dispersion.

  7. Supramolecular polymers in inhomogeneous systems

    NARCIS (Netherlands)

    Zweistra, H.J.A.

    2007-01-01

    This thesis describes theoretical results of supramolecular polymers in inhomogeneous systems. Supramolecular polymers are linear assemblies of which the monomers are joined by reversible bonds. Many types of supramolecular polymers have been synthesized in recent years. Moreover, there are numerous

  8. Binary Polymer Brushes of Strongly Immiscible Polymers.

    Science.gov (United States)

    Chu, Elza; Babar, Tashnia; Bruist, Michael F; Sidorenko, Alexander

    2015-06-17

    The phenomenon of microphase separation is an example of self-assembly in soft matter and has been observed in block copolymers (BCPs) and similar materials (i.e., supramolecular assemblies (SMAs) and homo/block copolymer blends (HBCs)). In this study, we use microphase separation to construct responsive polymer brushes that collapse to generate periodic surfaces. This is achieved by a chemical reaction between the minor block (10%, poly(4-vinylpyridine)) of the block copolymer and a substrate. The major block of polystyrene (PS) forms mosaic-like arrays of grafted patches that are 10-20 nm in size. Depending on the nature of the assembly (SMA, HBC, or neat BCP) and annealing method (exposure to vapors of different solvents or heating above the glass transition temperature), a range of "mosaic" brushes with different parameters can be obtained. Successive grafting of a secondary polymer (polyacrylamide, PAAm) results in the fabrication of binary polymer brushes (BPBs). Upon being exposed to specific selective solvents, BPBs may adopt different conformations. The surface tension and adhesion of the binary brush are governed by the polymer occupying the top stratum. The "mosaic" brush approach allows for a combination of strongly immiscible polymers in one brush. This facilitates substantial contrast in the surface properties upon switching, previously only possible for substrates composed of predetermined nanostructures. We also demonstrate a possible application of such PS/PAAm brushes in a tunable bioadhesion-bioadhesive (PS on top) or nonbioadhesive (PAAm on top) surface as revealed by Escherichia coli bacterial seeding.

  9. Triclosan antimicrobial polymers

    Directory of Open Access Journals (Sweden)

    Richard C. Petersen

    2016-03-01

    Full Text Available Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are enhanced even better through secondary bonding relationships. Further, polymer blend compatibilization is considered due to similar molecular relationships and polarities. With compatibilization of triclosan in polymers a more uniform stability for nonpolar triclosan in the polymer solid state is retained by the antimicrobial for extremely low release with minimum solubility into aqueous solution. As a result, triclosan is projected for long extended lifetimes as an antimicrobial polymer additive. Further, triclosan rapid alternating ether bond rotations disrupt secondary bonding between chain monomers in the resin state to reduce viscosity and enhance polymer blending. Thus, triclosan is considered for a polymer additive with multiple properties to be an antimicrobial with additional benefits as a nonpolar toughening agent and a hydrophobic wetting agent. The triclosan material relationships with alternating ether bond rotations are described through a complete different form of medium by comparisons with known antimicrobial properties that upset bacterial cell membranes through rapid fluctuating mechanomolecular energies. Also, triclosan bond entanglements with secondary bonding can produce structural defects in weak bacterial lipid membranes requiring pliability that can then interfere with cell division. Regarding applications with polymers, triclosan can be incorporated by mixing into a resin system before cure, melt mixed with thermoplastic polymers

  10. Triclosan antimicrobial polymers

    Science.gov (United States)

    Petersen, Richard C.

    2016-01-01

    Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are enhanced even better through secondary bonding relationships. Further, polymer blend compatibilization is considered due to similar molecular relationships and polarities. With compatibilization of triclosan in polymers a more uniform stability for nonpolar triclosan in the polymer solid state is retained by the antimicrobial for extremely low release with minimum solubility into aqueous solution. As a result, triclosan is projected for long extended lifetimes as an antimicrobial polymer additive. Further, triclosan rapid alternating ether bond rotations disrupt secondary bonding between chain monomers in the resin state to reduce viscosity and enhance polymer blending. Thus, triclosan is considered for a polymer additive with multiple properties to be an antimicrobial with additional benefits as a nonpolar toughening agent and a hydrophobic wetting agent. The triclosan material relationships with alternating ether bond rotations are described through a complete different form of medium by comparisons with known antimicrobial properties that upset bacterial cell membranes through rapid fluctuating mechanomolecular energies. Also, triclosan bond entanglements with secondary bonding can produce structural defects in weak bacterial lipid membranes requiring pliability that can then interfere with cell division. Regarding applications with polymers, triclosan can be incorporated by mixing into a resin system before cure, melt mixed with thermoplastic polymers that set on cooling

  11. Doped Chiral Polymer Metamaterials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Doped Chiral Polymer Metamaterials (DCPM) with tunable resonance frequencies have been developed by adding plasmonic inclusions into chiral polymers with variable...

  12. Aliphatic polyester block polymers: renewable, degradable, and sustainable.

    Science.gov (United States)

    Hillmyer, Marc A; Tolman, William B

    2014-08-19

    Nearly all polymers are derived from nonrenewable fossil resources, and their disposal at their end of use presents significant environmental problems. Nonetheless, polymers are ubiquitous, key components in myriad technologies and are simply indispensible for modern society. An important overarching goal in contemporary polymer research is to develop sustainable alternatives to "petro-polymers" that have competitive performance properties and price, are derived from renewable resources, and may be easily and safely recycled or degraded. Aliphatic polyesters are particularly attractive targets that may be prepared in highly controlled fashion by ring-opening polymerization of bioderived lactones. However, property profiles of polyesters derived from single monomers (homopolymers) can limit their applications, thus demanding alternative strategies. One such strategy is to link distinct polymeric segments in an A-B-A fashion, with A and B chosen to be thermodynamically incompatible so that they can self-organize on a nanometer-length scale and adopt morphologies that endow them with tunable properties. For example, such triblock copolymers can be useful as thermoplastic elastomers, in pressure sensitive adhesive formulations, and as toughening modifiers. Inspired by the tremendous utility of petroleum-derived styrenic triblock copolymers, we aimed to develop syntheses and understand the structure-property profiles of sustainable alternatives, focusing on all renewable and all readily degradable aliphatic polyester triblocks as targets. Building upon oxidation chemistry reported more than a century ago, a constituent of the peppermint plant, (-)-menthol, was converted to the ε-caprolactone derivative menthide. Using a diol initiator and controlled catalysis, menthide was polymerized to yield a low glass transition temperature telechelic polymer (PM) that was then further functionalized using the biomass-derived monomer lactide (LA) to yield fully renewable PLA

  13. Mechanically Invisible Polymer Coatings

    DEFF Research Database (Denmark)

    2014-01-01

    phase comprises particles, said particles comprising a filler material and an encapsulating coating of a second polymeric material, wherein the backbones of the first and second polymeric materials are the same. The composition may be used in electroactive polymers (EAPs) in order to obtain mechanically...... invisible polymer coatings....

  14. Tunable Optical Polymer Systems

    Science.gov (United States)

    2007-11-02

    outperforms almost all other organic polymer systems reported thus far, the introduction of the first multiple color LBL electrochrome , and development...thin films outperform previously reported LBL assembled films and approach integration capability for a number of electrochromic , sensing and...Zacharia, N; Hammond, P. T. “ Electrochromism of LBL assembled thin polymer films containing metal oxide nanoparticles,” American Chemical Society

  15. Polymer Electronics, Quo Vadis?

    NARCIS (Netherlands)

    Chiechi, Ryan C.; Hummelen, Jan C.

    2012-01-01

    At the heart of polymer electronics lies more than three decades of research into conjugated polymers. The future of these materials is intimately tied to the development of organic photovoltaic (OPV) devices that can compete with traditional, inorganic devices in efficiency and cost. In addition to

  16. Polymer Electronics, Quo Vadis?

    NARCIS (Netherlands)

    Chiechi, Ryan C.; Hummelen, Jan C.

    2012-01-01

    At the heart of polymer electronics lies more than three decades of research into conjugated polymers. The future of these materials is intimately tied to the development of organic photovoltaic (OPV) devices that can compete with traditional, inorganic devices in efficiency and cost. In addition to

  17. Stiff Quantum Polymers

    OpenAIRE

    Kleinert, H

    2007-01-01

    At ultralow temperatures, polymers exhibit quantum behavior, which is calculated here for the second and fourth moments of the end-to-end distribution in the large-stiffness regime. The result should be measurable for polymers in wide optical traps.

  18. Melons are branched polymers

    CERN Document Server

    Gurau, Razvan

    2013-01-01

    Melonic graphs constitute the family of graphs arising at leading order in the 1/N expansion of tensor models. They were shown to lead to a continuum phase, reminiscent of branched polymers. We show here that they are in fact precisely branched polymers, that is, they possess Hausdorff dimension 2 and spectral dimension 4/3.

  19. Radioluminescent polymer lights

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, G.A.; Nelson, D.A.; Molton, P.M.

    1990-09-01

    The preparation of radioluminescent light sources where the tritium is located on the aryl-ring in a polymer has been demonstrated with deuterium/tritium substitution. This report discusses tests, results, and future applications of radioluminescent polymers. 10 refs. (FI)

  20. Polymers in Waveguide Packaging

    Institute of Scientific and Technical Information of China (English)

    Zhiyi Zhang; G. Z.Xiao; Jiaren Liu; C. P. Grover

    2003-01-01

    Polymers were successfully used in the packaging of waveguide-based photonic components in the area of fiber-to-waveguide coupling, waveguide die attachment, strain relief, and waveguide encapsulation. The application results of these polymers were described in this paper.

  1. Semiconducting polymer LEDs

    Directory of Open Access Journals (Sweden)

    David Braun

    2002-06-01

    The field of semiconducting polymers has its root in the 1977 discovery of the semiconducting properties of polyacetylene1. This breakthrough earned Alan Heeger, Alan MacDiarmid, and Hideki Shirakawa the 2000 Nobel Prize in Chemistry for ‘the discovery and development of conductive polymers’2–5. Other review articles capture how more than two decades of developments in the physical and chemical understanding of these novel materials has led to new device applications as active and passive electronic and optoelectronic devices ranging from diodes and transistors to polymer LEDs, photodiodes, lasers, and solar cells6–11. Much interest in plastic devices derives from the opportunities to use clever control of polymer structure combined with relatively economical polymer synthesis and processing techniques to obtain simultaneous control over electronic, optical, chemical, and mechanical features5. This article focuses on the advances leading to polymer LEDs12–14.

  2. Polymer wear evaluation

    DEFF Research Database (Denmark)

    Lagerbon, Mikkel; Sivebæk, Ion Marius

    2012-01-01

    the safety of the patients. Prediction of the wear of polymers is complicated by the low thermal conductivity of this kind of material. It implies that any acceleration of testing conditions by increased contact pressure and/or sliding velocity will make the polymer fail due to exaggerated heat buildup......Polymer wear plays an increasing role in manufacturing of machine parts for e.g. medical devices. Some of these have an expected lifetime of five to eight years during which very little wear of the components is acceptable. Too much wear compromises the dosage accuracy of the device and thereby....... This is not the kind of wear observed in medical devices. In the present work a method was developed capable of evaluating the wear progression in polymer-polymer contacts. The configuration of the setup is injection moulded specimens consisting of an upper part having a toroid shape and a lower flat part. The sliding...

  3. Polymer electrolyte reviews. 1

    Energy Technology Data Exchange (ETDEWEB)

    Mac Callum, J.R.; Vincent, C.A.

    1987-01-01

    The development of polymer electrolytes which have potential applications in battery technology has resulted in an escalation of research into the synthesis of new macromolecular supports and the mechanisms of ionic transport within the solid matrix. Investigation of the properties of polymer electrolytes has brought together polymer chemists and electrochemists, and the understanding of the solubility and transport of electrolytes in organic polymers is now developing from this pooled experience. This book deals with experimental, theoretical and applied aspects of solid solutions of electrolytes used in coordinating polymer matrices. Attention is focused on the synthesis and properties of these new materials, the mechanisms of conduction processes and practical applications, especially with regard to battery technology.

  4. Polymer wear evaluation

    DEFF Research Database (Denmark)

    Lagerbon, Mikkel; Sivebæk, Ion Marius

    2012-01-01

    Polymer wear plays an increasing role in manufacturing of machine parts for e.g. medical devices. Some of these have an expected lifetime of five to eight years during which very little wear of the components is acceptable. Too much wear compromises the dosage accuracy of the device and thereby...... the safety of the patients. Prediction of the wear of polymers is complicated by the low thermal conductivity of this kind of material. It implies that any acceleration of testing conditions by increased contact pressure and/or sliding velocity will make the polymer fail due to exaggerated heat buildup....... This is not the kind of wear observed in medical devices. In the present work a method was developed capable of evaluating the wear progression in polymer-polymer contacts. The configuration of the setup is injection moulded specimens consisting of an upper part having a toroid shape and a lower flat part. The sliding...

  5. H-Bonded Liquid Crystalline Polymer Network Materials

    Institute of Scientific and Technical Information of China (English)

    LIN Hong-Cheu; HENDRIANTO Jemmy

    2001-01-01

    @@Side-chain copolymers, poly(mOBA-co-mStilb)s, composed of proton acceptors (stilbazoles) and proton donors (benzoic acids) connected to polyacrylate backbone with different methylene spacer lengths (m = 6 and 10) were prepared in different donor/acceptor molar ratios. The H-bonded copolymeric networks were formed once they were synthesized, and showed more homogenous phase than the physical-blended supramolecular networks consisting of donor and acceptor homopolymers, i.e.H-bonded blends of PmOBA and PmStilb. In order to compare the effects of the backbone connection of these H-bonded copolymers and blends, we also built monomer-monomer and polymer-monomer H-bonded complexes of similar structures (shown in Fig. 1). DSC, POM, and powder XRD studies reveal that the copolymers (m = 10)with mole fractions of benzoic acids between 0.33-0.83 show the smectic A (SMA) phase with layer spacing values between 42.22A-50.47A (increases with higher H-bonded crosslinking density between benzoic acids and stilbazoles), while for m = 6, liquid crystalline behavior still can be observed at 0.89 molar fraction of benzoic acids. However, on the basis of powder XRD study it is found that the d spacing values of H-bonded copolymers with m = 6 in the SmA phase increase with higher molar ratios of benzoic acids, which is agreed with the formation of microphase separation due to the hydrogen bonds of benzoic acids connected themselves from the same backbone. The isotropization temperatures of the H-bonded copolymers and blends increase as the molar ratios of benzoic acids increase, while the higher crosslinking density of the H-bonded copolymeric networks and blends can stabilize the liquid crystalline phase.

  6. H-Bonded Liquid Crystalline Polymer Network Materials

    Institute of Scientific and Technical Information of China (English)

    LIN; Hong-Cheu

    2001-01-01

    Side-chain copolymers, poly(mOBA-co-mStilb)s, composed of proton acceptors (stilbazoles) and proton donors (benzoic acids) connected to polyacrylate backbone with different methylene spacer lengths (m = 6 and 10) were prepared in different donor/acceptor molar ratios. The H-bonded copolymeric networks were formed once they were synthesized, and showed more homogenous phase than the physical-blended supramolecular networks consisting of donor and acceptor homopolymers, i.e.H-bonded blends of PmOBA and PmStilb. In order to compare the effects of the backbone connection of these H-bonded copolymers and blends, we also built monomer-monomer and polymer-monomer H-bonded complexes of similar structures (shown in Fig. 1). DSC, POM, and powder XRD studies reveal that the copolymers (m = 10)with mole fractions of benzoic acids between 0.33-0.83 show the smectic A (SMA) phase with layer spacing values between 42.22A-50.47A (increases with higher H-bonded crosslinking density between benzoic acids and stilbazoles), while for m = 6, liquid crystalline behavior still can be observed at 0.89 molar fraction of benzoic acids. However, on the basis of powder XRD study it is found that the d spacing values of H-bonded copolymers with m = 6 in the SmA phase increase with higher molar ratios of benzoic acids, which is agreed with the formation of microphase separation due to the hydrogen bonds of benzoic acids connected themselves from the same backbone. The isotropization temperatures of the H-bonded copolymers and blends increase as the molar ratios of benzoic acids increase, while the higher crosslinking density of the H-bonded copolymeric networks and blends can stabilize the liquid crystalline phase.……

  7. LH-PP/Nano-clay共混挤出的发泡成型%Extrusion Foaming of Linear Polypropylene Homopolymer/Nano-Clay Blends

    Institute of Scientific and Technical Information of China (English)

    王明义; 纪莲清; 马军; 周南桥

    2011-01-01

    Foaming process of linear polypropylene homopolymer(LH-PP)/nano-clay blends was investigated using a single extruder foaming system,with supercritical carbon dioxide as the foaming agent and maleic anhydride grafted polypropylene(PP-g-MAH) as the coupling agent.Influences of die temperature and blending formulation on foam expansion ratio,cell-population density and die pressure were analyzed.Result shows the addition of nano-clay and PP-g-MAH increases the maximum expansion ratio of foamed samples obtained.Compared with pure LH-PP,the addition of nano-clay and PP-g-MAH decreases the foaming temperature of LH-PP/nano-clay/PP-g-MAH blends as maximum expansion ratio is achieved.In addition,we found the curve of the final expansion ratio of PP foam vs.temperature shows a typical mountain shape for each formulation,indicating that gas loss and crystallization stiffening of the melt at low temperature are the two governing factors influencing foam expansion ratio of semi-crystalline polymers.%以超临界CO2为发泡剂,马来酸酐接枝改性聚丙烯(PP-g-MAH)为相容剂,使用单螺杆挤出发泡系统研究了线性均聚聚丙烯(LH-PP)/纳米粘土(Nano-clay)共混物的发泡成型过程,研究了口模温度和共混配方对发泡样品膨胀率、泡孔密度以及口模压力的影响。研究发现,Nano-clay和PP-g-MAH的加入提高了LH-PP/Nano-clay/PP-g-MAH共混物发泡样品的最大膨胀率,与纯LH-PP获得最大膨胀率的发泡温度相比,Nano-clay和PP-g-MAH的加入使得共混体系获得最大膨胀率的发泡温度向低温迁移。此外,研究发现发泡样品的最终膨胀率对温度的关系呈现一种山峰状分布,说明高温下的气体散失及低温下熔体的硬化结晶是影响半结晶聚合物发泡样品膨胀率的两个因素。

  8. Ion implantation in polymers

    Science.gov (United States)

    Wintersgill, M. C.

    1984-02-01

    An introductory overview will be given of the effects of ion implantation on polymers, and certain areas will be examined in more detail. Radiation effects in general and ion implantation in particular, in the field of polymers, present a number of contrasts with those in ionic crystals, the most obvious difference being that the chemical effects of both the implanted species and the energy transfer to the host may profoundly change the nature of the target material. Common effects include crosslinking and scission of polymer chains, gas evolution, double bond formation and the formation of additional free radicals. Research has spanned the chemical processes involved, including polymerization reactions achievable only with the use of radiation, to applied research dealing both with the effects of radiation on polymers already in commercial use and the tailoring of new materials to specific applications. Polymers are commonly divided into two groups, in describing their behavior under irradiation. Group I includes materials which form crosslinks between molecules, whereas Group II materials tend to degrade. In basic research, interest has centered on Group I materials and of these polyethylene has been studied most intensively. Applied materials research has investigated a variety of polymers, particularly those used in cable insulation, and those utilized in ion beam lithography of etch masks. Currently there is also great interest in enhancing the conducting properties of polymers, and these uses would tend to involve the doping capabilities of ion implantation, rather than the energy deposition.

  9. Polymer Science Pilot Program

    Science.gov (United States)

    Maier, Mary L.

    1996-07-01

    Natural polymers such as cellulose, proteins, and DNA have been part of earth's store of chemicals long before chemists existed. However, polymers synthesized by chemists first appeared on this planet only sixty years ago. A veritable explosion of materials first known as plastics, later polymers, followed. Today polymers, natural and synthetic, are everywhere, and it is appropriate to include an introduction to polymers in the education of future scientists. The Polymer Science Pilot Program consists of a sequence of experiences with polymers, designed to focus upon the ways in which these materials resemble and/or compare with nonpolymers in physical properties, versatility, and function. The modular format makes it possible for educators to select specific sections of the program for integration into other college chemistry courses. The team learning aspect of he program can also be recommended to educators who select a specific module. When this program was presented at a Middle Atlantic Regional Meeting of the American Chemical Society, some attendees were concerned about the limited number of participants as compared with the seemingly large number of college instructors. It was explained that the concentrated format of the four day program necessitates this instructor-to-student ratio; one class consisting of eighteen participants was tried and it was found that some aspects of the program, especially the research paper preparation, were not as thoroughly moderated.

  10. Biomedical applications of polymers

    CERN Document Server

    Gebelein, C G

    1991-01-01

    The biomedical applications of polymers span an extremely wide spectrum of uses, including artificial organs, skin and soft tissue replacements, orthopaedic applications, dental applications, and controlled release of medications. No single, short review can possibly cover all these items in detail, and dozens of books andhundreds of reviews exist on biomedical polymers. Only a few relatively recent examples will be cited here;additional reviews are listed under most of the major topics in this book. We will consider each of the majorclassifications of biomedical polymers to some extent, inclu

  11. Soluble porphyrin polymers

    Science.gov (United States)

    Gust, Jr., John Devens; Liddell, Paul Anthony

    2015-07-07

    Porphyrin polymers of Structure 1, where n is an integer (e.g., 1, 2, 3, 4, 5, or greater) ##STR00001## are synthesized by the method shown in FIGS. 2A and 2B. The porphyrin polymers of Structure 1 are soluble in organic solvents such as 2-MeTHF and the like, and can be synthesized in bulk (i.e., in processes other than electropolymerization). These porphyrin polymers have long excited state lifetimes, making the material suitable as an organic semiconductor for organic electronic devices including transistors and memories, as well as solar cells, sensors, light-emitting devices, and other opto-electronic devices.

  12. Polymer artificial muscles

    Directory of Open Access Journals (Sweden)

    Tissaphern Mirfakhrai

    2007-04-01

    Full Text Available The various types of natural muscle are incredible material systems that enable the production of large deformations by repetitive molecular motions. Polymer artificial muscle technologies are being developed that produce similar strains and higher stresses using electrostatic forces, electrostriction, ion insertion, and molecular conformational changes. Materials used include elastomers, conducting polymers, ionically conducting polymers, and carbon nanotubes. The mechanisms, performance, and remaining challenges associated with these technologies are described. Initial applications are being developed, but further work by the materials community should help make these technologies applicable in a wide range of devices where muscle-like motion is desirable.

  13. Microstructured polymer optical fibres

    CERN Document Server

    Large, Maryanne; Barton, Geoff; van Eijkelenborg, Martijn A

    2008-01-01

    Microstructured Polymer Optical Fibres describes the optical properties of microstructured fibres, how they are made and modelled, and outlines some potential applications. These applications include areas where polymer fibres are already used, such as high-data rate transmission for Fibre-to-the Home or within cars, as well as completely new areas such as the photonic bandgap transmission of ""difficult"" wavelengths. Emphasising a conceptual understanding of the underlying physics, Microstructured Polymer Optical Fibres is clearly written, and includes numerous illustrations. It provides an

  14. Development of Silicate Polymers

    DEFF Research Database (Denmark)

    Søgaard, Erik Gydesen; Simonsen, Morten Enggrob

      The development of inorganic polymers is a new promising technology that may be used in many applications. The syntheses of inorganic polymers are normally carried out either by mixing an amorphous material for example silicium dioxide with a mineral base or dissolving metal oxids or metal...... hydroxide in acid and increase pH to saturation of the metal hydroxide. It is assumed that the syntheses of the inorganic polymer are carried out through polymerisation of oligomers (dimer, trimer) which provide the actual unit structures of the three dimensional macromolecular structure. In this work...

  15. The influence of surface curvature on polymer behavior at inorganic surfaces

    Science.gov (United States)

    Nunnery, Grady A.

    Nanoscale surfaces were examined in order to determine the influence of surface curvature on polymer behavior at polymer-ceramic interfaces, as well as the influence of nanoparticles in cellulosic media. Poly(methyl methacrylate) and block copolymers thereof were adsorbed onto porous alumina substrates of various pore sizes in order to determine how polymer and copolymer adsorption behavior at nanoscale surfaces differs from adsorption onto flat surfaces. It was determined that chain density on concave surfaces dramatically decreases as curvature increases in much the same way that it does on convex surfaces (e.g. on the surface of nanoparticles), and physical models are provided to explain this similarity. Diblock copolymer adsorption is observed to vary dramatically with solvent quality and block asymmetry and can be correlated with the surface curvature very similarly to the adsorptive behavior of homopolymers on those same surfaces. The addition of nanoparticles to cellulosic media was investigated as a means to significantly modify the properties of cellulosic composites with minimal additions of nanoparticles. Although cellulose is among the most abundant polymers on earth, its primary uses are limited to bulk commodity goods, such as paper and textiles. This work demonstrates a simple means to control cellulosic fluid viscosity, thereby increasing the versatility of these biopolymers in additional applications with higher value-added potential. The formation of iron-cellulosic nanocomposites by the in-situ thermolysis of metal carbonyls to form metallic nanoparticles was performed and was analyzed by viscometry among other techniques. It was determined that the nanocomposites that were formed exhibited significantly increased viscosity, up to the point of gelation. Additionally, an introduction to the expansive field of nanocomposites is provided, including how and why composite properties change abruptly as filler size approaches the nanoscale. An extensive

  16. Reactive polymer fused deposition manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Kunc, Vlastimil; Rios, Orlando; Love, Lonnie J.; Duty, Chad E.; Johs, Alexander

    2017-05-16

    Methods and compositions for additive manufacturing that include reactive or thermosetting polymers, such as urethanes and epoxies. The polymers are melted, partially cross-linked prior to the depositing, deposited to form a component object, solidified, and fully cross-linked. These polymers form networks of chemical bonds that span the deposited layers. Application of a directional electromagnetic field can be applied to aromatic polymers after deposition to align the polymers for improved bonding between the deposited layers.

  17. Polymers Best Paper Award 2015

    Directory of Open Access Journals (Sweden)

    Alexander Böker

    2015-01-01

    Full Text Available Polymers is instituting an annual award to recognize the outstanding papers in the area of polymer science published in Polymers. We are pleased to announce the second “Polymers Best Paper Award” for 2015 [1]. Nominations were selected by the Editor-in-Chief and Editorial Board members of Polymers from all papers published in 2011. The awards are issued to reviews and articles respectively. We are pleased to announce that the following five papers were chosen:[...

  18. Edible Polymers: Challenges and Opportunities

    OpenAIRE

    Shit, Subhas C.; Pathik M. Shah

    2014-01-01

    Edible polymers have established substantial deliberation in modern eons because of their benefits comprising use as edible materials over synthetic polymers. This could contribute to the reduction of environmental contamination. Edible polymers can practically diminish the complexity and thus improve the recyclability of materials, compared to the more traditional non-environmentally friendly materials and may be able to substitute such synthetic polymers. A synthetic hydrogel polymer unlock...

  19. Synthesis of polymer nano-brushes by self-seeding method and study of various morphologies by AFM

    Science.gov (United States)

    Agbolaghi, S.; Abbaspoor, S.; Abbasi, F.

    2016-11-01

    Polymer brushes due to their high sensitivity to environmental changes are the best and newest means for developing the responsive materials. Polymer nano-brushes consisting various surface morphologies and uniformly distributed amorphous grafted chains were synthesized via single-crystal growth procedure. Poly(ethylene glycol)- b-polystyrene (PEG- b-PS) and poly(ethylene glycol)- b-poly(methyl methacrylate) (PEG- b-PMMA) block copolymers were prepared by atom transfer radical polymerization (ATRP). On the basis of various height differences, phase regions were detectable through atomic force microscopy (AFM NanoscopeIII). The novelty of this work is developing and characterizing the random and intermediate single-co-crystals. Besides, some other sorts of brush-covered single crystals like homo-brush and matrix-dispersed mixed-brushes were involved just for comparing the distinct morphologies. The intermediate (neither matrix-dispersed nor random) single-co-crystals were detectable through their thickness fluctuations in AFM height profiles. On the contrary, the random single-co-crystals were verified through comparing with their corresponding homopolymer and homo-brush single crystals. The growth fronts of (120), (240), (200) and (040) were detected by electron diffraction of transmission electron microscope.

  20. Conductive Polymer Binder for High-Tap-Density Nanosilicon Material for Lithium-Ion Battery Negative Electrode Application.

    Science.gov (United States)

    Zhao, Hui; Wei, Yang; Qiao, Ruimin; Zhu, Chenhui; Zheng, Ziyan; Ling, Min; Jia, Zhe; Bai, Ying; Fu, Yanbao; Lei, Jinglei; Song, Xiangyun; Battaglia, Vincent S; Yang, Wanli; Messersmith, Phillip B; Liu, Gao

    2015-12-09

    High-tap-density silicon nanomaterials are highly desirable as anodes for lithium ion batteries, due to their small surface area and minimum first-cycle loss. However, this material poses formidable challenges to polymeric binder design. Binders adhere on to the small surface area to sustain the drastic volume changes during cycling; also the low porosities and small pore size resulting from this material are detrimental to lithium ion transport. This study introduces a new binder, poly(1-pyrenemethyl methacrylate-co-methacrylic acid) (PPyMAA), for a high-tap-density nanosilicon electrode cycled in a stable manner with a first cycle efficiency of 82%-a value that is further improved to 87% when combined with graphite material. Incorporating the MAA acid functionalities does not change the lowest unoccupied molecular orbital (LUMO) features or lower the adhesion performance of the PPy homopolymer. Our single-molecule force microscopy measurement of PPyMAA reveals similar adhesion strength between polymer binder and anode surface when compared with conventional polymer such as homopolyacrylic acid (PAA), while being electronically conductive. The combined conductivity and adhesion afforded by the MAA and pyrene copolymer results in good cycling performance for the high-tap-density Si electrode.

  1. Thermodynamics of a Compressible Maier-Saupe Model Based on the Self-Consistent Field Theory of Wormlike Polymer

    Directory of Open Access Journals (Sweden)

    Ying Jiang

    2017-02-01

    Full Text Available This paper presents a theoretical formalism for describing systems of semiflexible polymers, which can have density variations due to finite compressibility and exhibit an isotropic-nematic transition. The molecular architecture of the semiflexible polymers is described by a continuum wormlike-chain model. The non-bonded interactions are described through a functional of two collective variables, the local density and local segmental orientation tensor. In particular, the functional depends quadratically on local density-variations and includes a Maier–Saupe-type term to deal with the orientational ordering. The specified density-dependence stems from a free energy expansion, where the free energy of an isotropic and homogeneous homopolymer melt at some fixed density serves as a reference state. Using this framework, a self-consistent field theory is developed, which produces a Helmholtz free energy that can be used for the calculation of the thermodynamics of the system. The thermodynamic properties are analysed as functions of the compressibility of the model, for values of the compressibility realizable in mesoscopic simulations with soft interactions and in actual polymeric materials.

  2. Special Concrete with Polymers

    National Research Council Canada - National Science Library

    Nicolae Angelescu; Ioana Ion; Darius Stanciu; José Barroso Aguiar; Elena Valentina Stoian; Vasile Bratu

    2016-01-01

    .... They were prepared epoxy resin polymer concrete, Portland cement, coarse and fine aggregate and to evaluate the influence of resin dosage on microstructures and density of such structures reinforced concrete mixtures...

  3. Polymer semiconductor crystals

    Directory of Open Access Journals (Sweden)

    Jung Ah Lim

    2010-05-01

    Full Text Available One of the long-standing challenges in the field of polymer semiconductors is to figure out how long interpenetrating and entangled polymer chains self-assemble into single crystals from the solution phase or melt. The ability to produce these crystalline solids has fascinated scientists from a broad range of backgrounds including physicists, chemists, and engineers. Scientists are still on the hunt for determining the mechanism of crystallization in these information-rich materials. Understanding the theory and concept of crystallization of polymer semiconductors will undoubtedly transform this area from an art to an area that will host a bandwagon of scientists and engineers. In this article we describe the basic concept of crystallization and highlight some of the advances in polymer crystallization from crystals to nanocrystalline fibers.

  4. Electroactive polymers for sensing

    Science.gov (United States)

    2016-01-01

    Electromechanical coupling in electroactive polymers (EAPs) has been widely applied for actuation and is also being increasingly investigated for sensing chemical and mechanical stimuli. EAPs are a unique class of materials, with low-moduli high-strain capabilities and the ability to conform to surfaces of different shapes. These features make them attractive for applications such as wearable sensors and interfacing with soft tissues. Here, we review the major types of EAPs and their sensing mechanisms. These are divided into two classes depending on the main type of charge carrier: ionic EAPs (such as conducting polymers and ionic polymer–metal composites) and electronic EAPs (such as dielectric elastomers, liquid-crystal polymers and piezoelectric polymers). This review is intended to serve as an introduction to the mechanisms of these materials and as a first step in material selection for both researchers and designers of flexible/bendable devices, biocompatible sensors or even robotic tactile sensing units. PMID:27499846

  5. Analysis of Synthetic Polymers.

    Science.gov (United States)

    Smith, Charles G.; And Others

    1989-01-01

    Reviews techniques for the characterization and analysis of synthetic polymers, copolymers, and blends. Includes techniques for structure determination, separation, and quantitation of additives and residual monomers; determination of molecular weight; and the study of thermal properties including degradation mechanisms. (MVL)

  6. THERMOCHROMIC POLYMER MATERIALS

    Institute of Scientific and Technical Information of China (English)

    A.Seeboth; A.Klukowska; R.Ruhmann; D.L(o)tzsch

    2007-01-01

    Thermochromic polymers will play an extremely important role in the next future.The physical background of thermochromism and the state of development of thermochromic polymers based on light absorption effects are reported.In detail.the interactions between the polymer matrix and the thermochromic composite-composed of leuco or indicator dyes-are discussed on a molecular level.Thermochromic hydrogels with extremely high transparency,an outstanding switching behavior from colorless to colored or between different colors is presented.Preparation of thermosetting and thermoplastic polymers,including the resulting optical,and,for the first time,the mechanical properties are discussed in relation to matrix tuned high-resistant microcapsules.

  7. Shape-memory polymers

    Directory of Open Access Journals (Sweden)

    Marc Behl

    2007-04-01

    Full Text Available Shape-memory polymers are an emerging class of active polymers that have dual-shape capability. They can change their shape in a predefined way from shape A to shape B when exposed to an appropriate stimulus. While shape B is given by the initial processing step, shape A is determined by applying a process called programming. We review fundamental aspects of the molecular design of suitable polymer architectures, tailored programming and recovery processes, and the quantification of the shape-memory effect. Shape-memory research was initially founded on the thermally induced dual-shape effect. This concept has been extended to other stimuli by either indirect thermal actuation or direct actuation by addressing stimuli-sensitive groups on the molecular level. Finally, polymers are introduced that can be multifunctional. Besides their dual-shape capability, these active materials are biofunctional or biodegradable. Potential applications for such materials as active medical devices are highlighted.

  8. Polymers for Protein Conjugation

    Directory of Open Access Journals (Sweden)

    Gianfranco Pasut

    2014-01-01

    Full Text Available Polyethylene glycol (PEG at the moment is considered the leading polymer for protein conjugation in view of its unique properties, as well as to its low toxicity in humans, qualities which have been confirmed by its extensive use in clinical practice. Other polymers that are safe, biodegradable and custom-designed have, nevertheless, also been investigated as potential candidates for protein conjugation. This review will focus on natural polymers and synthetic linear polymers that have been used for protein delivery and the results associated with their use. Genetic fusion approaches for the preparation of protein-polypeptide conjugates will be also reviewed and compared with the best known chemical conjugation ones.

  9. Synthesis and Properties of Micron-size Magnetic Polymer Spheres with Epoxy Groups%带环氧基的超顺磁性高分子微球的制备及其性能表征

    Institute of Scientific and Technical Information of China (English)

    刘先桥; 官月平; 邢建民; 马志亚; 刘会洲

    2003-01-01

    Micron-size superparamagnetic poly(styrene-divinylbenzene-glycidyl methacrylate) (PSt-DVB-GMA)spheres were prepared via a modified suspension copolymerization method. Oleic acid coated magnetite (Fe3O4)nanoparticles made by co-precipitation were first mixed with monomers of St, DVB, GMA, and benzoyl peroxide (BPO) to form oil in water suspension with the presence of poly(vinyl pyrrolidone) (PVP-K30) as a stabilizer.Then the temperature of mixture was increased at a controlled rate to obtain small and relatively uniform droplets.Finally, the copolymerization reaction was initiated by the decomposition of BPO. The morphology and properties of magnetic PSt-DVB-GMA microspheres were examined by SEM, TEM, VSM, XRD and FT-IR. The magnetic microspheres obtained have very small size (about 4-7μm) in diameter with narrow size distribution and superparamagnetic characteristics. Powder X-ray diffraction measurements show the inverse cubic spinel structure for the magnetite dispersed in polymer microspheres. FT-IR spectroscopy indicates extensive oxirane groups existed on the surface of magnetic PSt-DVB-GMA microspheres.

  10. Branched Polymer Revisited

    CERN Document Server

    Aoki, H; Kawai, H; Kitazawa, Y; Aoki, Hajime; Iso, Satoshi; Kawai, Hikaru; Kitazawa, Yoshihisa

    2000-01-01

    We show that correlation functions for branched polymers correspond to those for $\\phi^3$ theory with a single mass insertion, not those for the $\\phi^3$ theory themselves, as has been widely believed. In particular, the two-point function behaves as 1/p^4, not as 1/p^2. This behavior is consistent with the fact that the Hausdorff dimension of the branched polymer is four.

  11. Transferases in Polymer Chemistry

    Science.gov (United States)

    van der Vlist, Jeroen; Loos, Katja

    Transferases are enzymes that catalyze reactions in which a group is transferred from one compound to another. This makes these enzymes ideal catalysts for polymerization reactions. In nature, transferases are responsible for the synthesis of many important natural macromolecules. In synthetic polymer chemistry, various transferases are used to synthesize polymers in vitro. This chapter reviews some of these approaches, such as the enzymatic polymerization of polyesters, polysaccharides, and polyisoprene.

  12. Voltammetry of conducting polymers

    OpenAIRE

    Gulaboski, Rubin

    2014-01-01

    The search for new materials for enhancing electrical conductivity of various materials is one of the most active research areas today. Conducting polymers represent a unique class of organic materials that have been used in many applications such as bioelectronics, sensors, corrosion protection, electrocatalysis, and energy storage devices. Application of the conductive polymers in electrochemistry is almost inevitable in order to get better features of the voltammetric systems ...

  13. Polymer optical motherboard technology

    Science.gov (United States)

    Keil, N.; Yao, H.; Zawadzki, C.; Grote, N.; Schell, M.

    2008-02-01

    In this paper, different hybridly integrated optical devices including optical multiplexer/ demultiplexer and optical transceivers are described. The devices were made using polymer planar light wave circuit (P2LC) technology. Laser diodes, photodiodes, and thin-film filters have been integrated. Key issues involved in this technology, in particular the coupling between laser diodes and polymer waveguides, and between waveguides and photodiodes and also fibers are discussed.

  14. Active Polymer Gel Actuators

    OpenAIRE

    Shuji Hashimoto; Ryo Yoshida; Yusuke Hara; Shingo Maeda

    2010-01-01

    Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of he...

  15. Polymer-Based Therapeutics

    OpenAIRE

    Liu, Shuang; Maheshwari, Ronak; Kiick, Kristi L.

    2009-01-01

    Polymeric materials have been applied in therapeutic applications, such as drug delivery and tissue regeneration, for decades owing to their biocompatibility and suitable mechanical properties. In addition, select polymer–drug conjugates have been used as bioactive pharmaceuticals owing to their increased drug efficacy, solubility, and target specificity compared with small-molecule drugs. Increased synthetic control of polymer properties has permitted the production of polymer assemblies for...

  16. New ferrocene polymers

    Energy Technology Data Exchange (ETDEWEB)

    Tataru, L.; Vata, M.; Mazilu, I.; Lixandru, T.; Simionescu, C.

    1981-12-28

    New poly(ferroccenylene azomethines) were synthesized by polycondensation of 1,1'-diacetylferrocene and 1,1'-bis(..beta..-(2-furyl)-acryloyl) ferrocene with several aromatic diamines of the benzidine type and sulphynyl derivatives with ether, thioether or disulphide bridges between the benzene rings. The obtained polymers were stable up to 200/sup 0/C and showed semiconducting properties. The oxygen or sulphur atoms in the diamine component did not modify significantly the polymer properties.

  17. Natural polymers: an overview

    CSIR Research Space (South Africa)

    John, MJ

    2012-08-01

    Full Text Available bioplastics. There are two main types of natural polymers: those that come from living organisms (these include carbohydrates and proteins); and, those which need to be polymerized but come from renewable resources (lactic acid and triglycerides). Both... types are used in the production of bio-plastics. Among the different types of natural polymers, the best known resources capable of making biodegradable plastics are starch and cellulose. Cellulose is the most abundant carbohydrate in the world ? 40...

  18. Conductivity behaviour of polymer gel electrolytes: Role of polymer

    Indian Academy of Sciences (India)

    S S Sekhon

    2003-04-01

    Polymer is an important constituent of polymer gel electrolytes along with salt and solvent. The salt provides ions for conduction and the solvent helps in the dissolution of the salt and also provides the medium for ion conduction. Although the polymer added provides mechanical stability to the electrolytes yet its effect on the conductivity behaviour of gel electrolytes as well as the interaction of polymer with salt and solvent has not been conclusively established. The conductivity of lithium ion conducting polymer gel electrolytes decreases with the addition of polymer whereas in the case of proton conducting polymer gel electrolytes an increase in conductivity has been observed with polymer addition. This has been explained to be due to the role of polymer in increasing viscosity and carrier concentration in these gel electrolytes.

  19. Nanoimprinted polymer solar cell.

    Science.gov (United States)

    Yang, Yi; Mielczarek, Kamil; Aryal, Mukti; Zakhidov, Anvar; Hu, Walter

    2012-04-24

    Among the various organic photovoltaic devices, the conjugated polymer/fullerene approach has drawn the most research interest. The performance of these types of solar cells is greatly determined by the nanoscale morphology of the two components (donor/acceptor) and the molecular orientation/crystallinity in the photoactive layer. A vertically bicontinuous and interdigitized heterojunction between donor and acceptor has been regarded as one of the ideal structures to enable both efficient charge separation and transport. Synergistic control of polymer orientation in the nanostructured heterojunction is also critical to improve the performance of polymer solar cells. Nanoimprint lithography has emerged as a new approach to simultaneously control both the heterojunction morphology and polymer chains in organic photovoltaics. Currently, in the area of nanoimprinted polymer solar cells, much progress has been achieved in the fabrication of nanostructured morphology, control of molecular orientation/crystallinity, deposition of acceptor materials, patterned electrodes, understanding of structure-property correlations, and device performance. This review article summarizes the recent studies on nanoimprinted polymer solar cells and discusses the outstanding challenges and opportunities for future work.

  20. Rapid Polymer Sequencer

    Science.gov (United States)

    Stolc, Viktor (Inventor); Brock, Matthew W (Inventor)

    2013-01-01

    Method and system for rapid and accurate determination of each of a sequence of unknown polymer components, such as nucleic acid components. A self-assembling monolayer of a selected substance is optionally provided on an interior surface of a pipette tip, and the interior surface is immersed in a selected liquid. A selected electrical field is impressed in a longitudinal direction, or in a transverse direction, in the tip region, a polymer sequence is passed through the tip region, and a change in an electrical current signal is measured as each polymer component passes through the tip region. Each of the measured changes in electrical current signals is compared with a database of reference electrical change signals, with each reference signal corresponding to an identified polymer component, to identify the unknown polymer component with a reference polymer component. The nanopore preferably has a pore inner diameter of no more than about 40 nm and is prepared by heating and pulling a very small section of a glass tubing.

  1. Comparative Study of Structure-Property Relationships in Polymer Networks Based on Bis-GMA, TEGDMA and Various Urethane-Dimethacrylates

    Directory of Open Access Journals (Sweden)

    Izabela Barszczewska-Rybarek

    2015-03-01

    Full Text Available The effect of various dimethacrylates on the structure and properties of homo- and copolymer networks was studied. The 2,2-bis-[4-(2-hydroxy-3- methacryloyloxypropoxyphenyl]-propane (Bis-GMA, triethylene glycol dimethacrylate (TEGDMA and 1,6-bis-(methacryloyloxy-2-ethoxycarbonylamino-2,4,4-trimethylhexane (HEMA/TMDI, all popular in dentistry, as well as five urethane-dimethacrylate (UDMA alternatives of HEMA/TMDI were used as monomers. UDMAs were obtained from mono-, di- and tri(ethylene glycol monomethacrylates and various commercial diisocyanates. The chemical structure, degree of conversion (DC and scanning electron microscopy (SEM fracture morphology were related to the mechanical properties of the polymers: flexural strength and modulus, hardness, as well as impact strength. Impact resistance was widely discussed, being lower than expected in the case of poly(UDMAs. It was caused by the heterogeneous morphology of these polymers and only moderate strength of hydrogen bonds between urethane groups, which was not high enough to withstand high impact energy. Bis-GMA, despite having the highest polymer morphological heterogeneity, ensured fair impact resistance, due to having the strongest hydrogen bonds between hydroxyl groups. The TEGDMA homopolymer, despite being heterogeneous, produced the smoothest morphology, which resulted in the lowest brittleness. The UDMA monomer, having diethylene glycol monomethacrylate wings and the isophorone core, could be the most suitable HEMA/TMDI alternative. Its copolymer with Bis-GMA and TEGDMA had improved DC as well as all the mechanical properties.

  2. Structures of two O-chain polysaccharides of Citrobacter gillenii O9a,9b lipopolysaccharide. A new homopolymer of 4-amino-4,6-dideoxy-D-mannose (perosamine).

    Science.gov (United States)

    Lipiński, Tomasz; Zatonsky, George V; Kocharova, Nina A; Jaquinod, Michel; Forest, Eric; Shashkov, Alexander S; Gamian, Andrzej; Knirel, Yuriy A

    2002-01-01

    Mild acid degradation of the lipopolysaccharide of Citro- bacter gillenii O9a,9b released a polysaccharide (PS), which was found to consist of a single monosaccharide, 4- acetamido-4,6-dideoxy-d-mannose (d-Rha4NAc, N-acetyl-d-perosamine). PS was studied by methylation analysis and (1)H-NMR and (13)C-NMR spectroscopy, using two-dimensional (1)H,(1)H COSY, TOCSY, NOESY, and H-detected (1)H,(13)C heteronuclear correlation experiments. It was found that PS includes two structurally different polysaccharides: an alpha1-->2-linked homopolymer of N-acetyl-d-perosamine [-->2)-alpha-d-Rhap4NAc-(1-->, PS2] and a polysaccharide composed of tetrasaccharide repeating units (PS1) with the following structure: -->3)-alpha-d-Rhap4NAc-(1-->2)-alpha-d-Rhap4NAc-(1-->2)-alpha-d-Rhap4NAc-(1-->3)-alpha-d-Rhap4 N Ac2Ac-(1--> where the degree of O-acetylation of a 3-substituted Rha4NAc residue at position 2 is approximately 70%. PS could be fractionated into PS1 and PS2 by gel-permeation chromatography on TSK HW-50S. Matrix-assisted laser desorption ionization MS data indicate sequential chain elongation of both PS1 and PS2 by a single sugar unit, with O-acetylation in PS1 beginning at a certain chain length. Anti-(C. gillenii O9a,9b) serum reacted with PS1 in double immunodiffusion and immunoblotting, whereas neither PS2 nor the lipopolysaccharide of Vibrio cholerae O1 with a structurally related O-chain polysaccharide were reactive.

  3. East Coalinga polymer project: polymer comparisons. [California

    Energy Technology Data Exchange (ETDEWEB)

    Snell, G.

    1976-01-01

    Shell Oil Co. conducted a series of injection and filtration tests in the E. Colainga field, California, to determine the injection characteristics of biopolymer and polyacrylamides. The choice of Xanflood biopolymer was made in order to evaluate the relative merits of polymer flooding and waterflooding in the Temblor Zone II reservoir. Conclusions to the field injection tests were (1) Xanflood biopolymers maintain their mobility properties during these tests; (2) it is possible to remove unhydrated Xanflood biopolymer or unhydrated biopolymer and bacterial debris with DE Filtration without significant loss in biopolymer viscosity; (3) the introduction of an optimum level of shear in the biopolymer mixing process increases the mobility control available for a given concentration of polymer; (4) currently available commercial biopolymers cause well-bore impairment so that effective filtration of the polymer solution is required to maintain injectivity; (5) at test injection rates (33 bpd/ft), polyacrylamide loses most of its mobility control by shear degradation at the injection well perforations; (6) polyacrylamide can be delivered to the sand face without severe loss of viscosity; and (7) polyacrylamide will not impair the formation. (12 refs.)

  4. Chaperone driven polymer translocation through Nanopore: spatial distribution and binding energy

    CERN Document Server

    Abdolvahab, Rouhollah Haji

    2016-01-01

    Chaperones are binding proteins which work as a driving force to bias the biopolymer translocation by binding to it near the pore and preventing its backsliding. Chaperones may have different spatial distribution. Recently we show the importance of their spatial distribution in translocation and how it effects on sequence dependency of the translocation time. Here we focus on homopolymers and exponential distribution. As a result of the exponential distribution of chaperones, energy dependency of the translocation time will changed and one see a minimum in translocation time versus effective energy curve. The same trend can be seen in scaling exponent of time versus polymer length, $\\beta$ ($T\\sim\\beta$). Interestingly in some special cases e.g. chaperones of size $\\lambda=6$ and with exponential distribution rate of $\\alpha=5$, the minimum reaches even to amount of less than $1$ ($\\beta<1$). We explain the possibility of this rare result and base on a theoretical discussion we show that by taking into acc...

  5. Diffusion behaviour of additives in polypropylene in correlation with polymer properties.

    Science.gov (United States)

    Begley, T H; Brandsch, J; Limm, W; Siebert, H; Piringer, O

    2008-11-01

    The migration behaviour of polymer additives in 17 polypropylene (PP) samples is described. These samples cover the major types of PP used in food packaging. The diffusion coefficients of additives with relatively small molecular masses, M(r) = 136 (limonene), as well as the migration of typical antioxidants used in PP up to M(r) = 1178 (IRGANOX 1010), were measured at different temperatures. In addition, the diffusion data and percentages of xylene-soluble fractions were correlated. This enables a prediction of the migration behaviour of a PP sample by testing its 'isotactic index' with xylene. The results clearly indicate that PP can be subdivided, from the migration point of view, into the monophasic homopolymer (h-PP), the monophasic random copolymer (r-PP), and the heterophasic copolymer (heco-PP). The diffusion coefficients for r-PP are at least one order of magnitude higher than those of h-PP and comparable with the values for heco-PP. Upper limits for the diffusion values can be calculated based on the safety margin required by consumer protection laws.

  6. Precursor polymer compositions comprising polybenzimidazole

    Energy Technology Data Exchange (ETDEWEB)

    Klaehn, John R.; Peterson, Eric S.; Orme, Christopher J.

    2015-07-14

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  7. Precursor polymer compositions comprising polybenzimidazole

    Science.gov (United States)

    Klaehn, John R.; Peterson, Eric S.; Orme, Christopher J.

    2015-07-14

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  8. Surface tension of polymer melts - experimental investigations of its effect on polymer-polymer adhesion

    DEFF Research Database (Denmark)

    Jankova Atanasova, Katja; Islam, Mohammad Aminul; Hansen, Hans Nørgaard

    The surface tension of polymer melts is important for the bond strength of two component polymer parts through their roles in the process of wetting, adsorption and adhesion. This investigation deals with the influence of the melt surface tension and substrate surface energy on the polymer......-polymer bond strength during two component polymer processing. Polymer materials PS, POM, ABS, PEl, PEEK and PC are chosen for the investigation. Pendant drop method showed that in case of PS and POM, the melt surface tension was decreased with increasing temperature. The substrate surface energies....... The results and discussion presented in this paper reflect the temperature dependent behaviours of the surface tension and surface energy of polymers and their effects on the polymer-polymer bond strength....

  9. Surface tension of polymer melts - experimental investigations of its effects on polymer-polymer adhesion

    DEFF Research Database (Denmark)

    Islam, Mohammad Aminul; Jankova Atanasova, Katja; Hansen, Hans Nørgaard

    The surface tension of polymer melts is important for the bond strength of two component polymer parts through their roles in the process of wetting, adsorption and adhesion. This investigation deals with the influence of the melt surface tension and substrate surface energy on the polymer......-polymer bond strength during two component polymer processing. Polymer materials PS, POM, ABS, PEI, PEEK and PC are chosen for the investigation. Pendant drop method showed that in case of PS and POM, the melt surface tension was decreased with increasing temperature. The substrate surface energies....... The results and discussion presented in this paper reflect the temperature dependent behaviours of the surface tension and surface energy of polymers and their effects on the polymer-polymer bond strength....

  10. Jamming of Semiflexible Polymers

    Science.gov (United States)

    Hoy, Robert S.

    2017-02-01

    We study jamming in model freely rotating polymers as a function of chain length N and bond angle θ0. The volume fraction at jamming ϕJ(θ0) is minimal for rigid-rodlike chains (θ0=0 ), and increases monotonically with increasing θ0≤π /2 . In contrast to flexible polymers, marginally jammed states of freely rotating polymers are highly hypostatic, even when bond and angle constraints are accounted for. Large-aspect-ratio (small θ0) chains behave comparably to stiff fibers: resistance to large-scale bending plays a major role in their jamming phenomenology. Low-aspect-ratio (large θ0) chains behave more like flexible polymers, but still jam at much lower densities due to the presence of frozen-in three-body correlations corresponding to the fixed bond angles. Long-chain systems jam at lower ϕ and are more hypostatic at jamming than short-chain systems. Implications of these findings for polymer solidification are discussed.

  11. Modelling polymer draft gears

    Science.gov (United States)

    Wu, Qing; Yang, Xiangjian; Cole, Colin; Luo, Shihui

    2016-09-01

    This paper developed a new and simple approach to model polymer draft gears. Two types of polymer draft gears were modelled and compared with experimental data. Impact characteristics, in-train characteristics and frequency responses of these polymer draft gears were studied and compared with those of a friction draft gear. The impact simulations show that polymer draft gears can withstand higher impact speeds than the friction draft gear. Longitudinal train dynamics simulations show that polymer draft gears have significantly longer deflections than friction draft gears in normal train operations. The maximum draft gear working velocities are lower than 0.2 m/s, which are significantly lower than the impact velocities during shunting operations. Draft gears' in-train characteristics are similar to their static characteristics but are very different from their impact characteristics; this conclusion has also been reached from frequency response simulations. An analysis of gangway bridge plate failures was also conducted and it was found that they were caused by coupler angling behaviour and long draft gear deflections.

  12. Introduction to Polymer Nomenclature

    Directory of Open Access Journals (Sweden)

    V. Jarm

    2011-04-01

    Full Text Available Presented is a condensed review of the current state of polymer nomenclature according to IUPAC recommendations. Two nomenclature systems, the source-based and the structurebased, differ on the viewpoint of how the structure of a polymer is represented and named. In the simpler and traditionally more popular source-based nomenclature, a polymer is named by attaching the prefix “poly” to the name of the starting monomer, e.g. polystyrene. This system suffers from the lack of clear definitions or rules. The more complex structure-based system consists of naming a polymer as poly(constitutional repeating unit, e.g. poly(1-phenyletane-1,2-diil. However, for the identification, orientation and naming of the preferred constitutional repeating unit, a number of principles and rules, according to the IUPAC recommended nomenclature of organic compounds, should be known and used. Application of both systems to certain polymer structures and their illustration with numerous examples are described.

  13. Polymer Directed Protein Assemblies

    Directory of Open Access Journals (Sweden)

    Patrick van Rijn

    2013-05-01

    Full Text Available Protein aggregation and protein self-assembly is an important occurrence in natural systems, and is in some form or other dictated by biopolymers. Very obvious influences of biopolymers on protein assemblies are, e.g., virus particles. Viruses are a multi-protein assembly of which the morphology is dictated by poly-nucleotides namely RNA or DNA. This “biopolymer” directs the proteins and imposes limitations on the structure like the length or diameter of the particle. Not only do these bionanoparticles use polymer-directed self-assembly, also processes like amyloid formation are in a way a result of directed protein assembly by partial unfolded/misfolded biopolymers namely, polypeptides. The combination of proteins and synthetic polymers, inspired by the natural processes, are therefore regarded as a highly promising area of research. Directed protein assembly is versatile with respect to the possible interactions which brings together the protein and polymer, e.g., electrostatic, v.d. Waals forces or covalent conjugation, and possible combinations are numerous due to the large amounts of different polymers and proteins available. The protein-polymer interacting behavior and overall morphology is envisioned to aid in clarifying protein-protein interactions and are thought to entail some interesting new functions and properties which will ultimately lead to novel bio-hybrid materials.

  14. Enhancement of Polymer Cytocompatibility by Nanostructuring of Polymer Surface

    OpenAIRE

    Petr Slepička; Nikola Slepičková Kasálková; Lucie Bačáková; Zdeňka Kolská; Václav Švorčík

    2012-01-01

    Polymers with their advantageous physical, chemical, mechanical, and electrical properties and easy manufacturing are widely used in biology, tissue engineering, and medicine, for example, as prosthetic materials. In some cases the polymer usage may be impeded by low biocompatibility of common synthetic polymers. The biocompatibility can be improved by modification of polymer surface, for example, by plasma discharge, irradiation with ionizing radiation, and sometime subsequent grafting with ...

  15. 'Stuffed' conducting polymers

    DEFF Research Database (Denmark)

    Winther-Jensen, Bjørn; Chen, Jun; West, Keld

    2005-01-01

    Conducting polymers (CP) obtained by oxidative polymerization using iron(III) salts shrink when Fe(II) and the excess counter ions are washed out after polymerization. This phenomenon can be used to incorporate active molecules into the CP matrix via their addition to the wash liquid. In the pres......Conducting polymers (CP) obtained by oxidative polymerization using iron(III) salts shrink when Fe(II) and the excess counter ions are washed out after polymerization. This phenomenon can be used to incorporate active molecules into the CP matrix via their addition to the wash liquid....... In the present work we demonstrate this principle on three different CP's: polypyrrole (PPy), poly-terthiophene (PTTh) and poly(3,4-ethylenedioxy thiophene) (PEDT), using ferrocene as a model molecule to be trapped in the polymer films. (c) 2005 Elsevier Ltd. All rights reserved....

  16. Polymer Photovoltaic Cells

    Institute of Scientific and Technical Information of China (English)

    Jianhui Hou; Chunhe Yang; Erjun Zhou; Chang He; Zhan'ao Tan; Youjun He; Yongfang Li

    2005-01-01

    @@ 1Introduction Polymer photovoltaic cells (PPVCs) have attracted much attention recently because of its easy fabrication, low cost and possibility to make flexible devices[1]. PPVC is composed of a conjugated polymer/C60blend layer (photosensitive layer) sandwiched between a transparent ITO electrode and a metal electrode.When a light through ITO electrode irradiates on the photosensitive layer, the photons with appropriate energy will be absorbed by the conjugated polymer (CP) and excitons (electron-hole pair) are produced. The excitons move to the interface of CP/C60 where the electrons transfer to the LUMO of C60 and holes leave on the HOMO of the CP. The separated electrons migrate through the C60 network to and are collected by the metal electrode, and the holes migrate through the CP network to and are collected by the ITO electrode, so that the photocurrent and photovoltage are attained.

  17. Doped Chiral Polymer Metamaterials

    Science.gov (United States)

    Park, Cheol (Inventor); Kang, Jin Ho (Inventor); Gordon, Keith L. (Inventor); Sauti, Godfrey (Inventor); Lowther, Sharon E. (Inventor); Bryant, Robert G. (Inventor)

    2017-01-01

    Some implementations provide a composite material that includes a first material and a second material. In some implementations, the composite material is a metamaterial. The first material includes a chiral polymer (e.g., crystalline chiral helical polymer, poly-.gamma.-benzyl-L-glutamate (PBLG), poly-L-lactic acid (PLA), polypeptide, and/or polyacetylene). The second material is within the chiral polymer. The first material and the second material are configured to provide an effective index of refraction value for the composite material of 1 or less. In some implementations, the effective index of refraction value for the composite material is negative. In some implementations, the effective index of refraction value for the composite material of 1 or less is at least in a wavelength of one of at least a visible spectrum, an infrared spectrum, a microwave spectrum, and/or an ultraviolet spectrum.

  18. Antiviral Polymer Therapeutics

    DEFF Research Database (Denmark)

    Smith, Anton Allen Abbotsford

    2014-01-01

    The field of drug delivery is in essence an exercise in engineered pharmacokinetics. Methods of doing so have been developed through the introduction of a vehicle carrying the drug, either by encapsulation or covalent attachment. The emergence of polymer therapeutics in anticancer therapy has...... the examples of polymer therapeutics being applied as an antiviral treatment are few and far in-between. This work aims to explore antiviral therapeutics, specifically in context of hepatitis virus C (HCV) and HIV. The current treatment of hepatitis C consists of a combination of drugs, of which ribavirin....... Curiously, the therapeutic window of ribavirin was vastly improved in several of these polymers suggesting altered pharmacodynamics. The applicability of liver-targeting sugar moieties is likewise tested in a similarly methodical approach. The same technique of synthesis was applied with zidovudine to make...

  19. Nanostructured silicate polymer concrete

    Directory of Open Access Journals (Sweden)

    Figovskiy Oleg L'vovich

    2014-03-01

    Full Text Available It has been known that acid-resistant concretes on the liquid glass basis have high porosity (up to 18~20 %, low strength and insufficient water resistance. Significant increasing of silicate matrix strength and density was carried out by incorporation of special liquid organic alkali-soluble silicate additives, which block superficial pores and reduce concrete shrinkage deformation. It was demonstrated that introduction of tetrafurfuryloxisilane additive sharply increases strength, durability and shock resistance of silicate polymer concrete in aggressive media. The experiments showed, that the strength and density of silicate polymer concrete increase in case of decreasing liquid glass content. The authors obtained optimal content of silicate polymer concrete, which possesses increased strength, durability, density and crack-resistance. Diffusive permeability of concrete and its chemical resistance has been investigated in various corroding media.

  20. Active Polymer Gel Actuators

    Directory of Open Access Journals (Sweden)

    Shuji Hashimoto

    2010-01-01

    Full Text Available Many kinds of stimuli-responsive polymer and gels have been developed and applied to biomimetic actuators or artificial muscles. Electroactive polymers that change shape when stimulated electrically seem to be particularly promising. In all cases, however, the mechanical motion is driven by external stimuli, for example, reversing the direction of electric field. On the other hand, many living organisms can generate an autonomous motion without external driving stimuli like self-beating of heart muscles. Here we show a novel biomimetic gel actuator that can walk spontaneously with a wormlike motion without switching of external stimuli. The self-oscillating motion is produced by dissipating chemical energy of oscillating reaction. Although the gel is completely composed of synthetic polymer, it shows autonomous motion as if it were alive.

  1. Effect of intrachain sulfonic acid dopants on the solid-state charge mobility of a model radical polymer

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Holly; Wang, Yucheng; Boudouris, Bryan W., E-mail: boudouris@purdue.edu

    2015-02-27

    Radical polymers are an emerging class of non-conjugated, charge-conducting macromolecules that are capable of transporting charge through localized oxidation–reduction (redox) reactions that occur at the stable radical groups present as the pendant groups of the macromolecular chains. The chemical nature and oxidation state of these pendant radical groups are critical to the charge transporting abilities of radical polymers in the solid state. To date, however, the control of this chemistry has been limited to external oxidizing agents, and the concept of intramolecular dopants has not been explored fully. To this end, we have synthesized poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate)-co-poly(vinylsulfonic acid sodium salt) (PTMA-co-PVS). Then, electron paramagnetic resonance spectroscopy and attenuated total reflectance-Fourier transform infrared spectroscopy are implemented to evaluate the exact chemical nature of the pendant groups as a function of the PVS intramolecular dopants and exposure of the materials to external oxidation reactions. We correlate these changes in pendant group chemistry to charge transport ability, and we establish that the inclusion of a moderate amount of PVS dopants can improve the solid-state hole mobility of the material. Conversely, a large amount of sulfonic acidic dopants can be detrimental to the transport of the polymer relative to the homopolymer PTMA. Therefore, refinement of pendant group chemistry and careful addition of intramolecular dopants can enhance the solid-state transport ability of a radical polymer system. These fundamental principles, in turn, provide a vital foothold by which to optimize the solid-state charge transporting ability of current and next-generation radical polymer designs. - Highlights: • Sulfonic acid groups are copolymerized within the backbone of radical polymer chain. • Addition of the sulfonic acid groups alters the pendant group oxidation state. • Exact oxidation states are

  2. Conducting polymer 3D microelectrodes

    DEFF Research Database (Denmark)

    Sasso, Luigi; Vazquez, Patricia; Vedarethinam, Indumathi

    2010-01-01

    Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained...

  3. Composite solid polymer electrolyte membranes

    Energy Technology Data Exchange (ETDEWEB)

    Formato, Richard M. (Shrewsbury, MA); Kovar, Robert F. (Wrentham, MA); Osenar, Paul (Watertown, MA); Landrau, Nelson (Marlborough, MA); Rubin, Leslie S. (Newton, MA)

    2001-06-19

    The present invention relates to composite solid polymer electrolyte membranes (SPEMs) which include a porous polymer substrate interpenetrated with an ion-conducting material. SPEMs of the present invention are useful in electrochemical applications, including fuel cells and electrodialysis.

  4. Polymer Chemistry in High School.

    Science.gov (United States)

    Stucki, Roger

    1984-01-01

    Discusses why polymer chemistry should be added to the general chemistry curriculum and what topics are appropriate (listing traditional with related polymer topics). Also discusses when and how these topics should be taught. (JN)

  5. Polymers at cryogenic temperatures

    CERN Document Server

    Fu, Shao-Yun

    2013-01-01

    Kalia and Fu's novel monograph covers cryogenic treatment, properties and applications of cryo-treated polymer materials. Written by numerous international experts, the twelve chapters in this book offer the reader a comprehensive picture of the latest findings and developments, as well as an outlook on the field. Cryogenic technology has seen remarkable progress in the past few years and especially cryogenic properties of polymers are attracting attention through new breakthroughs in space, superconducting, magnetic and electronic techniques. This book is a valuable resource for researchers, educators, engineers and graduate students in the field and at technical institutions.

  6. Polymers and colloids

    Energy Technology Data Exchange (ETDEWEB)

    Schurtenberger, P. [ETH Zurich, Inst. fuer Polymere, Zurich (Switzerland)

    1996-11-01

    A wealth of structural information from colloid and polymer solutions on a large range of length scales can be obtained using small angle neutron scattering (SANS) experiments. After a general introduction to the field of soft condensed matter, I shall give a few selected examples on how SANS combined with suitable contrast variation schemes can be used to extract information on the size and conformation of polymer coils in solution and in the melt, and on the local structure and flexibility of polymerlike micelles and microemulsions. (author) 8 figs., tabs., 44 refs.

  7. Electrically Conducting Polymers.

    Science.gov (United States)

    1983-04-07

    polypyrrole, the oxidized polythiophene is also unstable in air. A rather different class of conducting polymers lies outside the scope of this review but...AD-A129 488 ELECTRICALLY CONDUCTING POLYNERS(U) IBM RESEARCH LAB / SAN JOSE CA W D GILL ET RL. 97 APR 83 TR-B UNCLASSIFIED F/G 7/3 N I Ihhhhhhhhhhhhl...00 Contract N00014-80-C-0779 Technical Report No. 8 *Electrically Conducting Polymers by W. D. Gill, T. C. Clarke, and G. B. Street Prepared for

  8. Delocalization in polymer models

    CERN Document Server

    Jitomirskaya, S Yu; Stolz, G

    2003-01-01

    A polymer model is a one-dimensional Schroedinger operator composed of two finite building blocks. If the two associated transfer matrices commute, the corresponding energy is called critical. Such critical energies appear in physical models, an example being the widely studied random dimer model. Although the random models are known to have pure-point spectrum with exponentially localized eigenstates for almost every configuration of the polymers, the spreading of an initially localized wave packet is here proven to be at least diffusive for every configuration.

  9. Shape memory polymer foams

    Science.gov (United States)

    Santo, Loredana

    2016-02-01

    Recent advances in shape memory polymer (SMP) foam research are reviewed. The SMPs belong to a new class of smart polymers which can have interesting applications in microelectromechanical systems, actuators and biomedical devices. They can respond to specific external stimulus changing their configuration and then remember the original shape. In the form of foams, the shape memory behaviour can be enhanced because they generally have higher compressibility. Considering also the low weight, and recovery force, the SMP foams are expected to have great potential applications primarily in aerospace. This review highlights the recent progress in characterization, evaluation, and proposed applications of SMP foams mainly for aerospace applications.

  10. Antibacterial polymer coatings.

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Mollye C.; Allen, Ashley N.; Barnhart, Meghan; Tucker, Mark David; Hibbs, Michael R.

    2009-09-01

    A series of poly(sulfone)s with quaternary ammonium groups and another series with aldehyde groups are synthesized and tested for biocidal activity against vegetative bacteria and spores, respectively. The polymers are sprayed onto substrates as coatings which are then exposed to aqueous suspensions of organisms. The coatings are inherently biocidal and do not release any agents into the environment. The coatings adhere well to both glass and CARC-coated coupons and they exhibit significant biotoxicity. The most effective quaternary ammonium polymers kills 99.9% of both gram negative and gram positive bacteria and the best aldehyde coating kills 81% of the spores on its surface.

  11. Nanoparticles from Renewable Polymers

    Science.gov (United States)

    Wurm, Frederik; Weiss, Clemens

    2014-07-01

    The use of polymers from natural resources can bring many benefits for novel polymeric nanoparticle systems. Such polymers have a variety of beneficial properties such as biodegradability and biocompatibility, they are readily available on large scale and at low cost. As the amount of fossil fuels decrease, their application becomes more interesting even if characterization is in many cases more challenging due to structural complexity, either by broad distribution of their molecular weights polysaccharides, polyesters, lignin) or by complex structure (proteins, lignin). This review summarizes different sources and methods for the preparation of biopolymer-based nanoparticle systems for various applications.

  12. Diagrammatic analysis of correlations in polymer fluids: Cluster diagrams via Edwards’ field theory

    Science.gov (United States)

    Morse, David C.

    2006-10-01

    Edwards' functional integral approach to the statistical mechanics of polymer liquids is amenable to a diagrammatic analysis in which free energies and correlation functions are expanded as infinite sums of Feynman diagrams. This analysis is shown to lead naturally to a perturbative cluster expansion that is closely related to the Mayer cluster expansion developed for molecular liquids by Chandler and co-workers. Expansion of the functional integral representation of the grand-canonical partition function yields a perturbation theory in which all quantities of interest are expressed as functionals of a monomer-monomer pair potential, as functionals of intramolecular correlation functions of non-interacting molecules, and as functions of molecular activities. In different variants of the theory, the pair potential may be either a bare or a screened potential. A series of topological reductions yields a renormalized diagrammatic expansion in which collective correlation functions are instead expressed diagrammatically as functionals of the true single-molecule correlation functions in the interacting fluid, and as functions of molecular number density. Similar renormalized expansions are also obtained for a collective Ornstein-Zernicke direct correlation function, and for intramolecular correlation functions. A concise discussion is given of the corresponding Mayer cluster expansion, and of the relationship between the Mayer and perturbative cluster expansions for liquids of flexible molecules. The application of the perturbative cluster expansion to coarse-grained models of dense multi-component polymer liquids is discussed, and a justification is given for the use of a loop expansion. As an example, the formalism is used to derive a new expression for the wave-number dependent direct correlation function and recover known expressions for the intramolecular two-point correlation function to first-order in a renormalized loop expansion for coarse-grained models of

  13. Polymer-solvent molecular compounds

    CERN Document Server

    Guenet, Jean-Michel

    2010-01-01

    Crystallisable polymers represent a large share of the polymers used for manufacturing a wide variety of objects, and consequently have received continuous attention from scientists these past 60 years. Molecular compounds from crystallisable polymers, particularly from synthetic polymers, are receiving growing interest due to their potential application in the making of new materials such as multiporous membranes capable of capturing large particles as well as small pollutant molecules. The present book gives a detailed description of these promising systems. The first chapter

  14. Turbulent drag reduction by polymers

    Energy Technology Data Exchange (ETDEWEB)

    Bonn, Daniel [Van der Waals-Zeeman Instituut, University of Amsterdam, Valckenierstraat 65 1018, XE Amsterdam (Netherlands); Amarouchene, Yacine [CPMOH, Universite Bordeaux 1, 351 Cours de la Liberation, 33405 Talence cedex (France); Wagner, Christian [Institut fuer Experimentalphysik, Universitaet des Saarlandes, Saarbruecken (Germany); Douady, Stephane [Laboratoire de Physique Statistique de l' ENS, 24 rue Lhomond, 75231 Paris cedex 05 (France); Cadot, Olivier [ENSTA, Chemin de la Huniere, 91761 Palaiseau cedex (France)

    2005-04-13

    The reduction of turbulent energy dissipation by addition of polymers is studied experimentally. We first address the question of where the action of the polymers is taking place. Subsequently, we show that there is a direct correlation of drag reduction with the elongational viscosity of the polymers. For this, the reduction of turbulent energy dissipation by addition of the biopolymer DNA is studied. These results open the way for a direct visualization study of the polymer conformation in a turbulent boundary layer.

  15. Shape memory polymer medical device

    Science.gov (United States)

    Maitland, Duncan; Benett, William J.; Bearinger, Jane P.; Wilson, Thomas S.; Small, IV, Ward; Schumann, Daniel L.; Jensen, Wayne A.; Ortega, Jason M.; Marion, III, John E.; Loge, Jeffrey M.

    2010-06-29

    A system for removing matter from a conduit. The system includes the steps of passing a transport vehicle and a shape memory polymer material through the conduit, transmitting energy to the shape memory polymer material for moving the shape memory polymer material from a first shape to a second and different shape, and withdrawing the transport vehicle and the shape memory polymer material through the conduit carrying the matter.

  16. Nonlinear microstructured polymer optical fibres

    DEFF Research Database (Denmark)

    Frosz, Michael Henoch

    is potentially the case for microstructured polymer optical fibres (mPOFs). Another advantage is that polymer materials have a higher biocompatibility than silica, meaning that it is easier to bond certain types of biosensor materials to a polymer surface than to silica. As with silica PCFs, it is difficult...

  17. Conjugated Polymer Zwitterions: Efficient Interlayer Materials in Organic Electronics.

    Science.gov (United States)

    Liu, Yao; Duzhko, Volodimyr V; Page, Zachariah A; Emrick, Todd; Russell, Thomas P

    2016-11-15

    quenching, possess optimal electron affinity that neither limits the work function reduction nor impedes the charge extraction, transport electrons selectively, and exhibit long-term stability. Our recent discoveries show that CPZs achieve many of these attributes, and are poised for further expansion and development in the interfacial science of organic electronics. This Account reviews a recent collaboration that began with the synthesis of CPZs and a study of their structural and electronic properties on metals, then extended to their application as interlayer materials for OPVs. We discuss CPZ structure-property relationships based on several material platforms, ranging from homopolymers to copolymers, and from materials with intrinsic p-type conjugated backbones to those with intrinsic n-type conjugated backbones. We discuss key components of such interlayers, including (i) the origin of work function reduction of CPZ interlayers on metals; (ii) the role of the frontier molecular orbital energy levels and their trade-offs in optimizing electronic and device properties; and (iii) the role of polymer conductivity type and the magnitude of charge carrier mobility. Our motivation is to present our prior use and current understanding of CPZs as interlayer materials in organic electronics, and describe outstanding issues and future potential directions.

  18. Polymers – A New Open Access Scientific Journal on Polymer Science

    OpenAIRE

    Shu-Kun Lin

    2009-01-01

    Polymers is a new interdisciplinary, Open Access scientific journal on polymer science, published by Molecular Diversity Preservation International (MDPI). This journal welcomes manuscript submissions on polymer chemistry, macromolecular chemistry, polymer physics, polymer characterization and all related topics. Both synthetic polymers and natural polymers, including biopolymers, are considered. Manuscripts will be thoroughly peer-reviewed in a timely fashion, and papers will be published, i...

  19. Dynamics of Polaron at Polymer/Polymer Interface

    Institute of Scientific and Technical Information of China (English)

    DI Bing; MENG Yan; AN Zhong; LI You-Cheng

    2008-01-01

    The migration of a polaron at polymer/polymer interface is believed to be of fundamental importance for the transport and light-emitting properties of conjugated polymer-based light emitting diodes.Based on the onedimensional tight-binding Su-Schrieffer-Heeger(SSH)model,we have investigated polaron dynamics in a onedimensional polymer/polymer system by using a nonadiabatic evolution method.In particular,we focus on how a polaron migrates through the conjugated polymer/polymer interface in the presence of external electric field.The results show that the migration of polaron at the interface depends sensitively on the hopping integrals,the potential barrier induced by the energy mismatch,and the strength of applied electric field which increases the polaron kinetic energy.

  20. Segmented conjugated polymers

    Indian Academy of Sciences (India)

    G Padmanaban; S Ramakrishnan

    2003-08-01

    Segmented conjugated polymers, wherein the conjugation is randomly truncated by varying lengths of non-conjugated segments, form an interesting class of polymers as they not only represent systems of varying stiffness, but also ones where the backbone can be construed as being made up of chromophores of varying excitation energies. The latter feature, especially when the chromophores are fluorescent, like in MEHPPV, makes these systems particularly interesting from the photophysics point of view. Segmented MEHPPV- samples, where x represents the mole fraction of conjugated segments, were prepared by a novel approach that utilizes a suitable precursor wherein selective elimination of one of the two eliminatable groups is affected; the uneliminated units serve as conjugation truncations. Control of the composition x of the precursor therefore permits one to prepare segmented MEHPPV- samples with varying levels of conjugation (elimination). Using fluorescence spectroscopy, we have seen that even in single isolated polymer chains, energy migration from the shorter (higher energy) chromophores to longer (lower energy) ones occurs – the extent of which depends on the level of conjugation. Further, by varying the solvent composition, it is seen that the extent of energy transfer and the formation of poorly emissive inter-chromophore excitons are greatly enhanced with increasing amounts of non-solvent. A typical S-shaped curve represents the variation of emission yields as a function of composition suggestive of a cooperative collapse of the polymer coil, reminiscent of conformational transitions seen in biological macromolecules.

  1. Primordial polymer perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Seahra, Sanjeev S.; Husain, Viqar [Department of Mathematics and Statistics, University of New Brunswick, Fredericton, NB, E3B 5A3 (Canada); Brown, Iain A. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315 Oslo (Norway); Hossain, Golam Mortuza, E-mail: sseahra@unb.ca, E-mail: ibrown@astro.uio.no, E-mail: ghossain@iiserkol.ac.in, E-mail: vhusain@unb.ca [Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur Campus, P.O. Krishi Viswavidyalaya, Nadia 741 252, WB (India)

    2012-10-01

    We study the generation of primordial fluctuations in pure de Sitter inflation where the quantum scalar field dynamics are governed by polymer (not Schroedinger) quantization. This quantization scheme is related to, but distinct from, the structures employed in Loop Quantum Gravity; and it modifies standard results above a polymer energy scale M{sub *}. We recover the scale invariant Harrison Zel'dovich spectrum for modes that have wavelengths bigger than M{sub *}{sup −1} at the start of inflation. The primordial spectrum for modes with initial wavelengths smaller than M{sub *}{sup −1} exhibits oscillations superimposed on the standard result. The amplitude of these oscillations is proportional to the ratio of the inflationary Hubble parameter H to the polymer energy scale. For reasonable choices of M{sub *}, we find that polymer effects are likely unobservable in CMB angular power spectra due to cosmic variance uncertainty, but future probes of baryon acoustic oscillations may be able to directly constrain the ratio H/M{sub *}.

  2. Glass Fibre Reinforced Polymers

    NARCIS (Netherlands)

    Nikolaou, N.; Karagianni, L.; Sarakiniatti, M.V.

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0533 Innovation & Sustainability. Fibre reinforced polymers (FRPs) have been used in many applications over the years, from new construction to retrofitting. They are lightweight, no-corrosive, exhibit high specific strength and specific

  3. Cyclic polymers from alkynes

    Science.gov (United States)

    Roland, Christopher D.; Li, Hong; Abboud, Khalil A.; Wagener, Kenneth B.; Veige, Adam S.

    2016-08-01

    Cyclic polymers have dramatically different physical properties compared with those of their equivalent linear counterparts. However, the exploration of cyclic polymers is limited because of the inherent challenges associated with their synthesis. Conjugated linear polyacetylenes are important materials for electrical conductivity, paramagnetic susceptibility, optical nonlinearity, photoconductivity, gas permeability, liquid crystallinity and chain helicity. However, their cyclic analogues are unknown, and therefore the ability to examine how a cyclic topology influences their properties is currently not possible. We have solved this challenge and now report a tungsten catalyst supported by a tetraanionic pincer ligand that can rapidly polymerize alkynes to form conjugated macrocycles in high yield. The catalyst works by tethering the ends of the polymer to the metal centre to overcome the inherent entropic penalty of cyclization. Gel-permeation chromatography, dynamic and static light scattering, viscometry and chemical tests are all consistent with theoretical predictions and provide unambiguous confirmation of a cyclic topology. Access to a wide variety of new cyclic polymers is now possible by simply choosing the appropriate alkyne monomer.

  4. Polymer concrete patching materials

    Energy Technology Data Exchange (ETDEWEB)

    Fontana, J.J.

    1977-09-01

    The increased use of deicing salts is causing rapid deterioration of portland cement concrete bridge decks. Soluble chlorides cause corrosion of the steel reinforcing rods with a corresponding increase in volume of the rods. This expansion causes stresses in the concrete which result in delaminations and surface spalling. The repair of surface spalls with portland cement concrete can only be made if traffic can be avoided for several days. A patching material which would allow traffic to resume over the repaired area in a few hours was needed. Polymer concrete (PC) was developed to repair deteriorated portland cement concrete. Polymer concrete is defined as a composite material in which the aggregate is bound together in a dense matrix with a polymer binder. The aggregate is mixed with a monomer mixture and subsequently cured in place. Polymer concrete combines the premix characteristics of portland cement concrete with high strength, long term durability properties and fast cure times. PC placed at temperatures between 35/sup 0/F and 95/sup 0/F attains strengths greater than 5000 psi in 2 hours. The high early strength of PC is suitable for use in the repair of highway structures where traffic conditions allow closing of the area for only a few hours.

  5. Transferases in Polymer Chemistry

    NARCIS (Netherlands)

    van der Vlist, Jeroen; Loos, Katja; Palmans, ARA; Heise, A

    2010-01-01

    Transferases are enzymes that catalyze reactions in which a group is transferred from one compound to another. This makes these enzymes ideal catalysts for polymerization reactions. In nature, transferases are responsible for the synthesis of many important natural macromolecules. In synthetic polym

  6. Glass Fibre Reinforced Polymers

    NARCIS (Netherlands)

    Nikolaou, N.; Karagianni, L.; Sarakiniatti, M.V.

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0533 Innovation & Sustainability. Fibre reinforced polymers (FRPs) have been used in many applications over the years, from new construction to retrofitting. They are lightweight, no-corrosive, exhibit high specific strength and specific sti

  7. Ion Implantation of Polymers

    DEFF Research Database (Denmark)

    Popok, Vladimir

    2012-01-01

    are discussed. Related to that, the effects of radiothermolysis, degassing and carbonisation are considered. Specificity of depth distributions of implanted into polymers impurities is analysed and the case of high-fluence implantation is emphasised. Within rather broad topic of ion bombardment, the focus...

  8. Conformational properties of polymers

    Indian Academy of Sciences (India)

    A R Singh; D Giri; S Kumar

    2008-08-01

    We discuss exact enumeration technique and its application to polymers and biopolymers. Using this method one can obtain phase diagram in thermodynamic limit. The method works quite well in describing the outcomes of single molecule force spectroscopy results where finite size effects play a crucial role.

  9. Simulating polymer liquid crystals

    NARCIS (Netherlands)

    Bladon, P.; Frenkel, D.

    1996-01-01

    A model suitable for simulating lyotropic polymer liquid crystals (PLCs) is described. By varying the persistence length between infinity and 25, the effect of increasing flexibility on the nematic - smectic transition of a PLC with a length-to-width ratio L/D = 6 is investigated. It is found that

  10. Surface tension of polymer melts - experimental investigations of its effect on polymer-polymer adhesion

    DEFF Research Database (Denmark)

    Jankova Atanasova, Katja; Islam, Mohammad Aminul; Hansen, Hans Nørgaard

    The surface tension of polymer melts is important for the bond strength of two component polymer parts through their roles in the process of wetting, adsorption and adhesion. This investigation deals with the influence of the melt surface tension and substrate surface energy on the polymer...

  11. Interpenetrating polymer network (IPN) nanogels based on gelatin and poly(acrylic acid) by inverse miniemulsion technique: synthesis and characterization.

    Science.gov (United States)

    Koul, Veena; Mohamed, Raja; Kuckling, Dirk; Adler, Hans-Jürgen P; Choudhary, Veena

    2011-04-01

    Novel interpenetrating polymer network (IPN) nanogels composed of poly(acrylic acid) and gelatin were synthesised by one pot inverse miniemulsion (IME) technique. This is based on the concept of nanoreactor and cross-checked from template polymerization technique. Acrylic acid (AA) monomer stabilized around the gelatin macromolecules in each droplet was polymerized using ammonium persulfate (APS) and tetramethyl ethylene diamine (TEMED) in 1:5 molar ratio and cross-linked with N,N-methylene bisacrylamide (BIS) to form semi-IPN (sIPN) nanogels, which were sequentially cross-linked using glutaraldehyde (Glu) to form IPNs. Span 20, an FDA approved surfactant was employed for the formation of homopolymer, sIPN and IPN nanogels. Formation of stable gelatin-AA droplets were observed at 2% surfactant concentration. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) studies of purified nanogels showed small, spherical IPN nanogels with an average diameter of 255 nm. In contrast, sIPN prepared using the same method gave nanogels of larger size. Fourier-transform infrared (FT-IR) spectroscopy, SEM, DLS, X-ray photoelectron spectroscopy (XPS) and zeta potential studies confirm the interpenetration of the two networks. Leaching of free PAA chains in sIPN upon dialysis against distilled water leads to porous nanogels. The non-uniform surface of IPN nanogels seen in transmission electron microscopy (TEM) images suggests the phase separation of two polymer networks. An increase of N/C ratio from 0.07 to 0.17 (from PAA gel to IPN) and O/C ratio from 0.22 to 0.37 (from gelatin gel to IPN) of the nanogels by XPS measurements showed that both polymer components at the nanogel surface are interpenetrated. These nanogels have tailoring properties in order to use them as high potential drug delivery vehicles for cancer targeting.

  12. Gel polymer electrolytes for batteries

    Science.gov (United States)

    Balsara, Nitash Pervez; Eitouni, Hany Basam; Gur, Ilan; Singh, Mohit; Hudson, William

    2014-11-18

    Nanostructured gel polymer electrolytes that have both high ionic conductivity and high mechanical strength are disclosed. The electrolytes have at least two domains--one domain contains an ionically-conductive gel polymer and the other domain contains a rigid polymer that provides structure for the electrolyte. The domains are formed by block copolymers. The first block provides a polymer matrix that may or may not be conductive on by itself, but that can soak up a liquid electrolyte, thereby making a gel. An exemplary nanostructured gel polymer electrolyte has an ionic conductivity of at least 1.times.10.sup.-4 S cm.sup.-1 at 25.degree. C.

  13. Frictional properties of confined polymers

    DEFF Research Database (Denmark)

    Sivebæk, Ion Marius; Samoilov, Vladimir N; Persson, Bo N J

    2008-01-01

    We present molecular dynamics friction calculations for confined hydrocarbon solids with molecular lengths from 20 to 1400 carbon atoms. Two cases are considered: a) polymer sliding against a hard substrate, and b) polymer sliding on polymer. In the first setup the shear stresses are relatively...... independent of molecular length. For polymer sliding on polymer the friction is significantly larger, and dependent on the molecular chain length. In both cases, the shear stresses are proportional to the squeezing pressure and finite at zero load, indicating an adhesional contribution to the friction force...

  14. Conjugated polymers based on benzo[2,1-b:3,4-b']dithiophene with low-lying highest occupied molecular orbital energy levels for organic photovoltaics.

    Science.gov (United States)

    Xiao, Shengqiang; Stuart, Andrew C; Liu, Shubin; You, Wei

    2009-07-01

    Fusing bithiophene units with a benzo moiety, benzo[2,1-b:3,4-b']dithiophene (BDT), was projected by theoretical calculations to lower the highest occupied molecular orbital (HOMO) energy level of the resulting polymers compared with that of the bithiophene unit, which would enhance the open circuit voltage of bulk heterojunction photovoltaic cells fabricated from BDT-based polymers blended with PCBM. The homopolymer of BDT (HMPBDT) and alternating copolymer of BDT with 2,1,3-benzothiadiazole (PBDT-BT) were therefore synthesized and fully characterized. Both the homopolymer (HMPBDT) and the copolymer (PBDT-BT) were experimentally confirmed to have low HOMO energy levels (-5.70 eV for HMPBDT and -5.34 eV for PBDT-BT). Introducing the acceptor moiety (2,1,3-benzothiadiazole) successfully lowered the optical band gap of the copolymer from 2.31 eV (HMPBDT) to 1.78 eV (PBDT-BT). Bulk heterojunction photovoltaic devices were fabricated from blends of these structurally related polymers with PBCM to investigate the photovoltaic performances. The optimized device of HMPBDT:PCBM (1:3, 180 nm) exhibited an improved open circuit voltage (V(oc)) of 0.76 V, a short circuit current (J(sc)) of 0.34 mA/cm(2), and a fill factor (FF) of 0.40, offering an overall efficiency of 0.10%. The observed large phase separation of the thin film by AFM and the large band gap were accountable for the small current. The optimized device of PBDT-BT:PCBM (1:3, 55 nm) demonstrated a better efficiency of 0.6%, with V(oc) = 0.72 V, J(sc) = 2.06 mA/cm(2), and FF = 0.42. The much improved current was attributed to the lower bandgap and better film morphology. However, the low hole mobility limited the thickness of the PBDT-BT:PCBM film, making inaccessible the thicker film which would utilize more light and enhance the current. Further improvements are expected if the mobility and film morphology can be improved by the new materials design, together with low band gap and low HOMO energy level.

  15. POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

    DEFF Research Database (Denmark)

    2001-01-01

    A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various...... thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes....... With the thermally resistant polymer, e.g., polybenzimidazole or a mixture of polybenzimidazole and other thermoplastics as binder, the carbon-supported noble metal catalyst is tape-cast onto a hydrophobic supporting substrate. When doped with an acid mixture, electrodes are assembled with an acid doped solid...

  16. Probing the causes of thermal hysteresis using tunable N agg micelles with linear and brush-like thermoresponsive coronas† †Electronic supplementary information (ESI) available: NMR spectra of small molecules and polymers, SEC chromatograms of the polymers, DLS, SLS and turbidimetry data for the micelles, a discussion of the chain density of micelles 11–15, additional calculations regarding the core composition of polymers 1–5 and definitions and calculations related to the light scattering data. See DOI: 10.1039/c6py01191h Click here for additional data file.

    Science.gov (United States)

    Blackman, L. D.

    2017-01-01

    Self-assembled thermoresponsive polymers in aqueous solution have great potential as smart, switchable materials for use in biomedical applications. In recent years, attention has turned to the reversibility of these polymers’ thermal transitions, which has led to debate over what factors influence discrepancies in the transition temperature when heating the system compared to the temperature obtained when cooling the system, known as the thermal hysteresis. Herein, we synthesize micelles with tunable aggregation numbers (N agg) whose cores contain poly(n-butyl acrylate-co-N,N-dimethylacrylamide) (p(nBA-co-DMA)) and four different thermoresponsive corona blocks, namely poly(N-isopropylacrylamide) (pNIPAM), poly(N,N-diethylacrylamide) (pDEAm), poly(diethylene glycol monomethyl ether methacrylate) (pDEGMA) and poly(oligo(ethylene glycol) monomethyl ether methacrylate) (pOEGMA). By studying their thermoresponsive behavior, we elucidate the effects of changing numerous important characteristics both in the thermoresponsive chain chemistry and architecture, and in the structure of their self-assemblies. Our findings demonstrate large deviations in the reversibility between the self-assemblies and the corresponding thermoresponsive homopolymers; specifically we find that micelles whose corona consist of polymers with a brush-like architecture (pDEGMA and pOEGMA) exhibit irreversible phase transitions at a critical chain density. These results lead to a deeper understanding of stimuli-responsive self-assemblies and demonstrate the potential of tunable N agg micelles for uncovering structure–property relationships in responsive polymer systems. PMID:28496523

  17. Adsorption and flocculation by polymers and polymer mixtures.

    Science.gov (United States)

    Gregory, John; Barany, Sandor

    2011-11-14

    Polymers of various types are in widespread use as flocculants in several industries. In most cases, polymer adsorption is an essential prerequisite for flocculation and kinetic aspects are very important. The rates of polymer adsorption and of re-conformation (relaxation) of adsorbed chains are key factors that influence the performance of flocculants and their mode of action. Polyelectrolytes often tend to adopt a rather flat adsorbed configuration and in this state their action is mainly through charge effects, including 'electrostatic patch' attraction. When the relaxation rate is quite low, particle collisions may occur while the adsorbed chains are still in an extended state and flocculation by polymer bridging may occur. These effects are now well understood and supported by much experimental evidence. In recent years there has been considerable interest in the use of multi-component flocculants, especially dual-polymer systems. In the latter case, there can be significant advantages over the use of single polymers. Despite some complications, there is a broad understanding of the action of dual polymer systems. In many cases the sequence of addition of the polymers is important and the pre-adsorbed polymer can have two important effects: providing adsorption sites for the second polymer or causing a more extended adsorbed conformation as a result of 'site blocking'. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. Synthesis of Stable and Soluble One-Handed Helical Homopoly(substituted acetylenes without the Coexistence of Any Other Chiral Moieties via Two-Step Polymer Reactions in Membrane State: Molecular Design of the Starting Monomer

    Directory of Open Access Journals (Sweden)

    Takashi Kaneko

    2012-01-01

    Full Text Available A soluble and stable one-handed helical poly(substituted phenylacetylene without the coexistence of any other chiral moieties was successfully synthesized by asymmetric-induced polymerization of a chiral monomer followed by two-step polymer reactions in membrane state: (1 removing the chiral groups (desubstitution; and (2 introduction of achiral long alkyl groups at the same position as the desubstitution to enhance the solubility of the resulting one-handed helical polymer (resubstitution. The starting chiral monomer should have four characteristic substituents: (i a chiral group bonded to an easily hydrolyzed spacer group; (ii two hydroxyl groups; (iii a long rigid hydrophobic spacer between the chiral group and the polymerizing group; (iv a long achiral group near the chiral group. As spacer group a carbonate ester was selected. The two hydroxyl groups formed intramolecular hydrogen bonds stabilizing a one-handed helical structure in solution before and after the two-step polymer reactions in membrane state. The rigid long hydrophobic spacer, a phenylethynylphenyl group, enhanced the solubility of the starting polymer, and realized effective chiral induction from the chiral side groups to the main chain in the asymmetric-induced polymerization. The long alkyl group near the chiral group avoided shrinkage of the membrane and kept the reactivity of resubstitution in membrane state after removing the chiral groups. The g value (g = ([θ]/3,300/ε for the CD signal assigned to the main chain in the obtained final polymer was almost the same as that of the starting polymer in spite of the absence of any other chiral moieties. Moreover, since the one-handed helical structure was maintained by the intramolecular hydrogen bonds in a solution, direct observation of the one-handed helicity of the final homopolymer has been realized in CD for the solution for the first time.

  19. Synthesis of stable and soluble one-handed helical homopoly(substituted acetylene)s without the coexistence of any other chiral moieties via two-step polymer reactions in membrane state: molecular design of the starting monomer.

    Science.gov (United States)

    Abe, Yunosuke; Aoki, Toshiki; Jia, Hongge; Hadano, Shingo; Namikoshi, Takeshi; Kakihana, Yuriko; Liu, Lijia; Zang, Yu; Teraguchi, Masahiro; Kaneko, Takashi

    2012-01-04

    A soluble and stable one-handed helical poly(substituted phenylacetylene) without the coexistence of any other chiral moieties was successfully synthesized by asymmetric-induced polymerization of a chiral monomer followed by two-step polymer reactions in membrane state: (1) removing the chiral groups (desubstitution); and (2) introduction of achiral long alkyl groups at the same position as the desubstitution to enhance the solubility of the resulting one-handed helical polymer (resubstitution). The starting chiral monomer should have four characteristic substituents: (i) a chiral group bonded to an easily hydrolyzed spacer group; (ii) two hydroxyl groups; (iii) a long rigid hydrophobic spacer between the chiral group and the polymerizing group; (iv) a long achiral group near the chiral group. As spacer group a carbonate ester was selected. The two hydroxyl groups formed intramolecular hydrogen bonds stabilizing a one-handed helical structure in solution before and after the two-step polymer reactions in membrane state. The rigid long hydrophobic spacer, a phenylethynylphenyl group, enhanced the solubility of the starting polymer, and realized effective chiral induction from the chiral side groups to the main chain in the asymmetric-induced polymerization. The long alkyl group near the chiral group avoided shrinkage of the membrane and kept the reactivity of resubstitution in membrane state after removing the chiral groups. The g value (g = ([θ]/3,300)/ε) for the CD signal assigned to the main chain in the obtained final polymer was almost the same as that of the starting polymer in spite of the absence of any other chiral moieties. Moreover, since the one-handed helical structure was maintained by the intramolecular hydrogen bonds in a solution, direct observation of the one-handed helicity of the final homopolymer has been realized in CD for the solution for the first time.

  20. Conjugated polymer nanoparticles, methods of using, and methods of making

    KAUST Repository

    Habuchi, Satoshi

    2017-03-16

    Embodiments of the present disclosure provide for conjugated polymer nanoparticle, method of making conjugated polymer nanoparticles, method of using conjugated polymer nanoparticle, polymers, and the like.

  1. Polymer Electrolyte Through Enzyme Catalysis for High Performance Lithium-Ion Batteries

    Science.gov (United States)

    2007-11-02

    copolymers where the comonomer is p-ethoxyphenol and p- phenylphenol known to undergo polymerization individually as described in references 3 and 4. Because...the homopolymer and its two copolymers. Conductivity decreases in the following order: homopolymer > ethoxyphenol copolymer > phenylphenol copolymer...interaction between the PEG segments in the copolymers. The difference between the ethoxyphenol copolymer and the phenylphenol copolymer can be explained by

  2. Microphase separation in hydrogen bonding polymer/surfactant melts

    NARCIS (Netherlands)

    Dormidontova, Elena; Brinke, Gerrit ten

    1999-01-01

    Phase behavior of solvent free mixtures of homopolymers and amphiphiles capable of hydrogen bonding is analyzed in weak segregation limit applying a theoretical model describing the main features of the system as a function of composition, temperature and strength of hydrogen bonding. Phase diagrams

  3. How do polymers degrade?

    Science.gov (United States)

    Lyu, Suping

    2011-03-01

    Materials derived from agricultural products such as cellulose, starch, polylactide, etc. are more sustainable and environmentally benign than those derived from petroleum. However, applications of these polymers are limited by their processing properties, chemical and thermal stabilities. For example, polyethylene terephthalate fabrics last for many years under normal use conditions, but polylactide fabrics cannot due to chemical degradation. There are two primary mechanisms through which these polymers degrade: via hydrolysis and via oxidation. Both of these two mechanisms are related to combined factors such as monomer chemistry, chain configuration, chain mobility, crystallinity, and permeation to water and oxygen, and product geometry. In this talk, we will discuss how these materials degrade and how the degradation depends on these factors under application conditions. Both experimental studies and mathematical modeling will be presented.

  4. Semi-metallic polymers

    DEFF Research Database (Denmark)

    Bubnova, Olga; Khan, Zia Ullah; Wang, Hui

    2014-01-01

    Polymers are lightweight, flexible, solution-processable materials that are promising for low-cost printed electronics as well as for mass-produced and large-area applications. Previous studies demonstrated that they can possess insulating, semiconducting or metallic properties; here we report...... suitable for thermoelectric applications. We measure the thermoelectric properties of various poly( 3,4-ethylenedioxythiophene) samples, and observe a marked increase in the Seebeck coefficient when the electrical conductivity is enhanced through molecular organization. This initiates the transition from...... that polymers can also be semi-metallic. Semi-metals, exemplified by bismuth, graphite and telluride alloys, have no energy bandgap and a very low density of states at the Fermi level. Furthermore, they typically have a higher Seebeck coefficient and lower thermal conductivities compared with metals, thus being...

  5. Photogenerating work from polymers

    Directory of Open Access Journals (Sweden)

    Hilmar Koerner

    2008-07-01

    Full Text Available The ability to control the creation of mechanical work remotely, with high speed and spatial precision, over long distances, offers many intriguing possibilities. Recent developments in photoresponsive polymers and nanocomposite concepts are at the heart of these future devices. Whether driving direct conformational changes, initiating reversible chemical reactions to release stored strain, or converting a photon to a local temperature increase, combinations of photoactive units, nanoparticles, ordered mesophases, and polymeric networks are providing an expansive array of photoresponsive polymer options for mechanical devices. Framing the typically geometry-specific observations into an applied engineering vocabulary will ultimately define the role of these materials in future actuator applications, ranging from microfluidic valves in medical devices to optically controlled mirrors in displays.

  6. Semiconducting polymers: the Third Generation.

    Science.gov (United States)

    Heeger, Alan J

    2010-07-01

    There has been remarkable progress in the science and technology of semiconducting polymers during the past decade. The field has evolved from the early work on polyacetylene (the First Generation material) to a proper focus on soluble and processible polymers and co-polymers. The soluble poly(alkylthiophenes) and the soluble PPVs are perhaps the most important examples of the Second Generation of semiconducting polymers. Third Generation semiconducting polymers have more complex molecular structures with more atoms in the repeat unit. Important examples include the highly ordered and crystalline PDTTT and the ever-growing class of donor-acceptor co-polymers that has emerged in the past few years. Examples of the latter include the bithiophene-acceptor co-polymers pioneered by Konarka and the polycarbazole-acceptor co-polymers pioneered by Leclerc and colleagues. In this tutorial review, I will summarize progress in the basic physics, the materials science, the device science and the device performance with emphasis on the following recent studies of Third Generation semiconducting polymers: stable semiconducting polymers; self-assembly of bulk heterojunction (BHJ) materials by spontaneous phase separation; bulk heterojunction solar cells with internal quantum efficiency approaching 100%; high detectivity photodetectors fabricated from BHJ materials.

  7. Polymer Stretching by Turbulence

    CERN Document Server

    Chertkov, M

    2000-01-01

    The stretching of a polymer chain by a large scale chaotic flow is considered. The steady state which emerges as a balance of the turbulent stretching and anharmonic resistance of the chain is quantitatively described, i.e. the dependency on the flow parameters (Lyapunov exponent statistics) and the chain characteristics (the number of beads and the inter-bead elastic potential) is made explicit. Implications for the drag reduction theory are discussed.

  8. Absorbable and biodegradable polymers

    CERN Document Server

    Shalaby, Shalaby W

    2003-01-01

    INTRODUCTION NOTES: Absorbable/Biodegradable Polymers: Technology Evolution. DEVELOPMENT AND APPLICATIONOF NEW SYSTEMS: Segmented Copolyesters with Prolonged Strength Retention Profiles. Polyaxial Crystalline Fiber-Forming Copolyester. Polyethylene Glycol-Based Copolyesters. Cyanoacrylate-Based Systems as Tissue Adhesives. Chitosan-Based Systems. Hyaluronic Acid-Based Systems. DEVELOPMENTS IN PREPARATIVE, PROCESSING, AND EVALUATION METHODS: New Approaches to the Synthesis of Crystalline. Fiber-Forming Aliphatic Copolyesters. Advances in Morphological Development to Tailor the Performance of Me

  9. Dynamics of polymers

    Energy Technology Data Exchange (ETDEWEB)

    Buchenau, U. [Forschungszentrum Juelich GmbH (Germany). Inst. fuer Energieverfahrenstechnik

    1996-11-01

    Neutron scattering from amorphous polymers allows to switch from incoherent to coherent scattering in the same substance. The power of the tool for the study of the picosecond dynamics of disordered matter is illustrated for polybutadiene, polycarbonate and polystyrene. The results suggest a mixture of sound waves and localized modes, strongly interacting with each other, in the picosecond range. (author) 8 figs., tabs., 39 refs.

  10. Electrochemical polymer electrolyte membranes

    CERN Document Server

    Fang, Jianhua; Wilkinson, David P

    2015-01-01

    Electrochemical Polymer Electrolyte Membranes covers PEMs from fundamentals to applications, describing their structure, properties, characterization, synthesis, and use in electrochemical energy storage and solar energy conversion technologies. Featuring chapters authored by leading experts from academia and industry, this authoritative text: Discusses cutting-edge methodologies in PEM material selection and fabricationPoints out important challenges in developing PEMs and recommends mitigation strategies to improve PEM performanceAnalyzes the cur

  11. Optimized Electroactive Polymer Supercapacitors

    Science.gov (United States)

    2014-09-08

    electrochromic device (ECD). ECDs were chosen for this demonstration for three reasons. First, ECDs have low operational power requirements and can be switched...switching an electrochromic device . Osterholm A.M.; Shen, D. E.; Dyer, A. L.; Reynolds, J. R. Optimization ofPEDOT Films in Ionic Liquid Supercapacitors...Demonstration as a Power Source for Polymer Electrochromic Devices ", ACS Appl. Mater. Interf. , 2013, 5, 13432. Enhancing Aqueous Compatability The

  12. Solution Processing - Rodlike Polymers

    Science.gov (United States)

    1979-08-01

    side it necessary and identify by block number) Para-ordered Polymers High Modulus Fibers and Films Polybenzobisoxazoles Polybenzobisthiazoles 20...considerations important in solution processing are considered, with special emphasis on the dry-jet wet spinning process used to form fibers . Pertinent...Company, Summit, N.J. iii TABLE OF CONTENTS 1. INTRODUCTION ................ .......................... .. 1 2. REMARKS ON DRY-JET WET SPUN FIBER

  13. Conjugated Polymer Solar Cells

    Science.gov (United States)

    2006-05-01

    oxygen since their EPR and conductivity data indicated the presence of unpaired charges. On the other hand, intramolecular CT complexes have recently...been reported for polythiophene [2], where weak CT occurs from a polymer unit cell to the covalently bonded acceptor molecule. Nevertheless, it was...intracavity optical doubler (532 nm), diode lasers (670, 810 nm) and light emitting diodes (490, 630 nm). Measurements were conducted for pump intensity 0.1

  14. Synthesis of Energetic Polymers.

    Science.gov (United States)

    1981-10-15

    50 system is a flowable oil at room temperature. The 75/25 mol% BAMO/THF is comparable in melting point to PEG 4000 (mp 550C). Although THF is a...conversion whereas THF reached a steady state of 85% after 38 hours. Based on the amount of monomers remaining, the final polymer composition was...elastomeric binders for use in propellant and explosive compositions . The copolymerization of 3,3-bis(azidomethyl) oxetane (BAMO) with tetrahydrofuran

  15. Conducting Thermoset Polymers.

    Science.gov (United States)

    2007-11-02

    polymers conducting. The acetylene-terminated Schiff base and acetylene-terminated polythiophene monomers were first cured, then doped with iodine... Schiff base thermoset was implanted with high energy argon ions using a commercial ion implanter. Electron spin resonance, photoluminescence, and...photoabsorption data suggest that polarons can form in the doped and undoped forms of the acetylene-terminated Schiff base and polythiophene thermoset

  16. Advanced Polymer Network Structures

    Science.gov (United States)

    2016-02-01

    Std. Z39.18 Approved for public release; distribution is unlimited. iii Contents List of Figures iv List of Tables v 1. Introduction 1 2...unlimited. v black and blue lines correspond to the single network composed of the first (system 10) and second networks (system 11), respectively...aggregation also contributes significantly to the tensile behavior, where the H- and comb - polymers with long spikes have a considerably higher

  17. CLASSIFICATION OF BIODEGRADABLE POLYMERS

    Directory of Open Access Journals (Sweden)

    I. I. Karpunin

    2015-01-01

    Full Text Available The executed investigations have made it possible to ascertain that a morphological structure of starch granules mainly determine technological peculiarities of starch isolation from raw material, its modification and its later use. Morphological structure of starch granules primarily depends on type of plant starch-containing raw material which has been used for its isolation. Class of raw material exerts a strong impact on the shape and size of the granules. Linear “light” amylose chains and “heavy” amylopectin branch chains form a starch granule ultrastructure. X-ray research has proved that starch granules are characterized by presence of interlacing amorphous and crystalline regions. In this case polymer orientation using stretching of the obtained end product influences on its physical and mechanical  indices which are increasing due to polymer orientation. For the purpose of packaging orientation of polymer films can solve such important problems as significant improvement of operational properties, creation of  thermosetting film materials, improvement of qualitative indices of the recycled film.Results of the conducted research have proved the fact that it is necessary to make changes in technology in order to increase biological degradability of the recycled packaging made from polymers and improve physical and mechanical indices. In this regard film production technology presupposes usage of such substances as stark and others which are characterized by rather large presence of branch chains of molecules and interlacing amorphous and crystalline regions. Such approach makes it possible to obtain after-use package which is strong and quickly degradable by micro-organisms.

  18. Photogenerating work from polymers

    OpenAIRE

    Hilmar Koerner; White, Timothy J.; Nelson V. Tabiryan; Timothy J. Bunning; Vaia, Richard A.

    2008-01-01

    The ability to control the creation of mechanical work remotely, with high speed and spatial precision, over long distances, offers many intriguing possibilities. Recent developments in photoresponsive polymers and nanocomposite concepts are at the heart of these future devices. Whether driving direct conformational changes, initiating reversible chemical reactions to release stored strain, or converting a photon to a local temperature increase, combinations of photoactive units, nanoparticle...

  19. Knots in polymers

    Indian Academy of Sciences (India)

    Yacov Kantov

    2005-06-01

    Knots and topological entanglements play an important role in the statistical mechanics of polymers. While topological entanglement is a global property, it is possible to study the size of a knotted region both numerically and analytically. It can be shown that long-range repulsive interactions, as well as entropy favor small knots in dilute systems. However, in dense systems and at the -point in two dimensions the uncontracted knot configuration is the most likely.

  20. Scratch behaviors in polymers

    Science.gov (United States)

    Xiang, Chen

    2000-10-01

    As part of a large effort toward the fundamental understanding of scratch behaviors in polymeric materials, studies were carried out on a broad range of polymers, with an emphasis on automotive thermoplastic olefins (TPOs). Two types of scratch tests were performed in this research, i.e., Ford constant load and instrumented progressive load scratch tests. A scratch model proposed by Hamilton and Goodman was applied to understand the fundamental mechanics of the scratch process. Several characterization techniques were used to investigate the scratch damage mechanisms in polymers. Both testing results and the scratch model analysis indicate that certain rigidity in polymers is essential to give good scratch resistance. Fundamental understanding of the scratching process in terms of basic material characteristics such as Young's modulus, yield stress, tensile strength, friction coefficient, scratch hardness, penetration recovery and fracture toughness are discussed. Scratch damage investigation, on both surface and subsurface, shows that shear yielding is the main cause of the plastics flow scratch pattern, while tensile tear on the surface and shear induced fracture on the subsurface are the main damage mechanisms in the fracture scratch pattern. This study explains why automotive TPOs are susceptible to scratch under the current scratch test practiced in automotive industry. Shear deformation and fracture behavior in model TPOs are also studied using the Iosipescu shear test. Iosipescu shear deformation in terms of shear stress-strain curves of model TPOs is obtained experimentally. Shear fracture process and damage mechanisms in TPOs are also demonstrated and revealed. Further studies on the scratch damage in TPOs based on the roles of additives and fillers in the scratch behavior are addressed. The effects of phase morphology and toughening mechanisms on scratch behavior in TPOs are also discussed. This research has resulted in an increased understanding of the

  1. Multifunctional e-spun colloidal nanofiber structures from various dispersed blends of PVA/ODA-MMT with PVP/ODA-MMT, poly(VP-alt-MA and AgNPs incorporated polymer complexes as electro-active platforms

    Directory of Open Access Journals (Sweden)

    U. Bunyatova

    2016-07-01

    Full Text Available This work presented a new approach to fabricate polymer nanocomposites films with nanofiber structures from solution blends of poly(vinyl alcohol + octadecyl amine-montmorillonite (ODA-MMT (matrix with poly(N-vinylpyrrolidone + ODA-MMT (partner-1, poly(N-vinylpyrrolidone-alt-maleic anhydride ((poly(VP-alt-MA + (ODA-MMT (partner-2 and their silver (Ag-carrying polymer complexes by electrospinning. Chemical and physical structures, surface morphologies, thermal behaviors, electrical conductivity and thermal resistance parameters of nanofiber structures were investigated. Poly(VP-alt-MA was used both as a crosslinker and a donor of the hydrophilic groups such as ‒COOH and ‒NH–C=O amide from pyrrolidone ring. Reactive poly(VP-alt-MA, in situ generated Ag nanoparticles (AgNPs and original partner polymer had an significant effect on the morphology and diameter distribution of nanofibers. High and excellent conductive behaviors were observed for the homopolymer and copolymer of VP based fiber structures, respectively. Upon successive chemical cross-linking of the nanofiber structures by reactive partner copolymer, the conductivity of nanofiber films as electro-active platforms dramatically increased to 3.90·10–2 S·cm–1 at room temperature. Comparative analysis results also indicated that electrical properties strongly depended on the loaded reactive organoclay and in situ generated AgNPs.

  2. Frustrated polymer crystal structures

    Science.gov (United States)

    Lotz, B.; Strasbourg, 67083

    1997-03-01

    Several crystal structures or polymorphs of chiral or achiral polymers and biopolymers with three fold conformation of the helix have been found to conform to a common and -with one exception(Puterman, M. et al, J. Pol. Sci., Pol. Phys. Ed., 15, 805 (1977))- hitherto unsuspected packing scheme. The trigonal unit-cell contains three isochiral helices; the azimuthal setting of one helix differs significantly from that of the other two, leading to a so-called frustrated packing scheme, in which the environment of conformationally identical helices differs. Two variants of the frustrated scheme are analyzed. Similarities with frustrated two dimensional magnetic systems are underlined. Various examples of frustration in polymer crystallography are illustrated via the elucidation or reinterpretation of crystal phases or polymorphs of polyolefins, polyesters, cellulose derivatives and polypeptides. Structural manifestations (including AFM evidence) and morphological consequences of frustration are presented, which help diagnose the existence of this original packing of polymers.(Work done with L. Cartier, D. Dorset, S. Kopp, T. Okihara, M. Schumacher, W. Stocker.)

  3. Semi-metallic polymers

    Science.gov (United States)

    Bubnova, Olga; Khan, Zia Ullah; Wang, Hui; Braun, Slawomir; Evans, Drew R.; Fabretto, Manrico; Hojati-Talemi, Pejman; Dagnelund, Daniel; Arlin, Jean-Baptiste; Geerts, Yves H.; Desbief, Simon; Breiby, Dag W.; Andreasen, Jens W.; Lazzaroni, Roberto; Chen, Weimin M.; Zozoulenko, Igor; Fahlman, Mats; Murphy, Peter J.; Berggren, Magnus; Crispin, Xavier

    2014-02-01

    Polymers are lightweight, flexible, solution-processable materials that are promising for low-cost printed electronics as well as for mass-produced and large-area applications. Previous studies demonstrated that they can possess insulating, semiconducting or metallic properties; here we report that polymers can also be semi-metallic. Semi-metals, exemplified by bismuth, graphite and telluride alloys, have no energy bandgap and a very low density of states at the Fermi level. Furthermore, they typically have a higher Seebeck coefficient and lower thermal conductivities compared with metals, thus being suitable for thermoelectric applications. We measure the thermoelectric properties of various poly(3,4-ethylenedioxythiophene) samples, and observe a marked increase in the Seebeck coefficient when the electrical conductivity is enhanced through molecular organization. This initiates the transition from a Fermi glass to a semi-metal. The high Seebeck value, the metallic conductivity at room temperature and the absence of unpaired electron spins makes polymer semi-metals attractive for thermoelectrics and spintronics.

  4. Sedimentation of Knotted Polymers

    CERN Document Server

    Piili, Joonas; Kaski, Kimmo; Linna, Riku

    2012-01-01

    We investigate the sedimentation of knotted polymers by means of the stochastic rotation dynamics, a molecular dynamics algorithm which takes hydrodynamics fully into account. We show that the sedimentation coefficient s, related to the terminal velocity of the knotted polymers, increases linearly with the average crossing number n_c of the corresponding ideal knot. To the best of our knowledge, this provides the first direct computational confirmation of this relation, postulated on the basis of experiments in "The effect of ionic conditions on the conformations of supercoiled DNA. I. sedimentation analysis" by Rybenkov et al., for the case of sedimentation. Such a relation was previously shown to hold with simulations for knot electrophoresis. We also show that there is an accurate linear dependence of s on the inverse of the radius of gyration R_g^-1, more specifically with the inverse of the R_g component that is perpendicular to the direction along which the polymer sediments. Intriguingly, the linear de...

  5. BioArtificial polymers

    Science.gov (United States)

    Szałata, Kamila; Gumi, Tania

    2017-07-01

    Nowadays, the polymer science has impact in practically all life areas. Countless benefits coming from the usage of materials with high mechanical and chemical resistance, variety of functionalities and potentiality of modification drive to the development of new application fields. Novel approaches of combining these synthetic substances with biomolecules lead to obtain multifunctional hybrid conjugates which merge the bioactivity of natural component with outstanding properties of artificial polymer. Over the decades, an immense progress in bioartificial composites domain allowed to reach a high level of knowledge in terms of natural-like systems engineering, leading to diverse strategies of biomolecule immobilization. Together with different available options, including covalent and noncovalent attachment, come various challenges, related mainly with maintaining the biological activity of fixed molecules. Even though the amount of applications that achieve commercial status is still not substantial, and is expanding continuously in the disciplines like "smart materials," biosensors, delivery systems, nanoreactors and many others. A huge number of remarkable developments reported in the literature present a potential of bioartificial conjugates as a fabrics with highly controllable structure and multiple functionalities, serving as a powerful nanotechnological tool. This novel approach brings closer biologists, chemists and engineers, who sharing their effort and complementing the knowledge can revolutionize the field of bioartificial polymer science.

  6. Hyperbranched Polymer-Based Electrolyte for Lithium Polymer Batteries

    Institute of Scientific and Technical Information of China (English)

    Takahito Itoh

    2005-01-01

    @@ 1Introduction Solid polymer electrolytes have attracted much attention as electrolyte materials for all solid-state recharge able lithium batteries, and poly ( ethylene oxide) ( PEO)-based polymer electrolytes are among the most intensively studied systems[1-3]. Hyperbranched polymers have unique properties such as completely amorphous, highly soluble in common organic solvent and processible because of the highly branched nature[4,5].

  7. Polymer crowding and shape distributions in polymer-nanoparticle mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Wei Kang; Denton, Alan R., E-mail: alan.denton@ndsu.edu [Department of Physics, North Dakota State University, Fargo, North Dakota 58108-6050 (United States)

    2014-09-21

    Macromolecular crowding can influence polymer shapes, which is important for understanding the thermodynamic stability of polymer solutions and the structure and function of biopolymers (proteins, RNA, DNA) under confinement. We explore the influence of nanoparticle crowding on polymer shapes via Monte Carlo simulations and free-volume theory of a coarse-grained model of polymer-nanoparticle mixtures. Exploiting the geometry of random walks, we model polymer coils as effective penetrable ellipsoids, whose shapes fluctuate according to the probability distributions of the eigenvalues of the gyration tensor. Accounting for the entropic cost of a nanoparticle penetrating a larger polymer coil, we compute the crowding-induced shift in the shape distributions, radius of gyration, and asphericity of ideal polymers in a theta solvent. With increased nanoparticle crowding, we find that polymers become more compact (smaller, more spherical), in agreement with predictions of free-volume theory. Our approach can be easily extended to nonideal polymers in good solvents and used to model conformations of biopolymers in crowded environments.

  8. Dynamic Polymer Brush at Polymer/Water Interface

    Science.gov (United States)

    Yokoyama, Hideaki; Inoue, Kazuma; Ito, Kohzo; Inutsuka, Manabu; Tanaka, Keiji; Yamada, Norifumi

    2015-03-01

    A layer of polymer chains tethered by one end to a surface is called polymer brush and known to show various unique properties such as anti-fouling. The surface segregation phenomena of copolymers with surface-active blocks should be useful for preparing such a brush layer in spontaneous process. We report hydrophilic polymer brushes formed at the interface between water and polymer by the segregation of amphiphilic diblock copolymers blended in a crosslinked rubbery matrix and call it ``dynamic polymer brush.'' In this system, the hydrophilic block with high surface energy avoids air surface, but segregates to cover the interface between hydrophobic elastomer and water. The structures of the brush layers at D2O/polymer interfaces were measured by neutron reflectivity. The dynamic polymer brush layer surprisingly reached 75% of the contour length of the chain and 2.7 chains/nm2. The brush density was surprisingly comparable to the polymer brush fabricated by the ``grafting-from'' method. We will discuss the dependence of the brush structure on molecular weight and block fraction of amphiphilic block copolymers. Such a surprisingly thick and dense polymer brush were induced by the large enthalpy gain of hydration of hydrophilic block.

  9. Molecular Thermodynamic Model for Associated Polymers

    Institute of Scientific and Technical Information of China (English)

    PENG,Chang-Jun(彭昌军); LIU,Hong-Lai(刘洪来); HU,Ying(胡英)

    2001-01-01

    A molecular thermedynmnic model for homopolyrner and copolymer systems with association segments was establishedby adopting the molecular thermodynamic model for hard-sphere-chain fluid as a reference,a perturbation term contributed by the square-well potential and a contribution of as sociation terms.The latter considers the multi-associated-seg-ments in a chain-like molecule based on the shield-sticky model of chemical association.The model can be used to correlate the pVT of melten homopolymer and copolymer.Good agree-ments with experimental data have been obtained.

  10. Dynamics of Polymer Chains.

    Science.gov (United States)

    Hong, Tzay-Ming

    A major objective of this research is to establish at a more fundamental level some of the qualitative or semi-quantitative treatments in use at the present time, such as the Doi-Edwards tube picture, the switch from non -ideal to ideal behavior, and dynamical aspects of the reptation model. The main topics are: (I) An attempt was made to determine the order of magnitude of the elastic time interval of a viscoelastic polymer melt, defining it as the reciprocal of the average rate at which the total entanglement (clockwise plus anticlockwise) passes through zero due to thermal agitation. We calculated the case of a free chain winding about a straight rod both in friction-independent regime and in high friction regime. (II) By successively coarse -graining and rescaling the monomer-monomer interaction (using a modified Wilson recursion formula) we found that the interaction is driven to a very strong but short-ranged one. This verifies the observation that polymers in dilute solutions tend to curl up and behave like hard spheres. (III) We studied the case of chemical equilibrium of i-mers with their nucleating monomers and on the basis of a Flory-Huggins -type mean field theory find that in the dilute limit the swelling of the i-mers takes on the traditional N ^{3over5} law only for sufficiently small monomer chemical potential. When that potential is large enough, then, assuming a Flory law of chain propagation, the law seems to become N^{1over3 }. This is distinct from the problem of changeover from dilute to semidilute polymer system, which we also studied by imposing total polymer density as a constraint equation. (IV) Another item examined concerns the form of the space curve that a very long polymer must assume in order to minimize its free energy (we found that a family of helices with a definite functional relation between pitch and radius renders the free energy stationary). Because a chain is a one-dimensional object, this does not mean that helical shapes

  11. Application of Targeted Molecular and Material Property Optimization to Bacterial Attachment-Resistant (Meth)acrylate Polymers.

    Science.gov (United States)

    Adlington, Kevin; Nguyen, Nam T; Eaves, Elizabeth; Yang, Jing; Chang, Chien-Yi; Li, Jianing; Gower, Alexandra L; Stimpson, Amy; Anderson, Daniel G; Langer, Robert; Davies, Martyn C; Hook, Andrew L; Williams, Paul; Alexander, Morgan R; Irvine, Derek J

    2016-09-12

    Developing medical devices that resist bacterial attachment and subsequent biofilm formation is highly desirable. In this paper, we report the optimization of the molecular structure and thus material properties of a range of (meth)acrylate copolymers which contain monomers reported to deliver bacterial resistance to surfaces. This optimization allows such monomers to be employed within novel coatings to reduce bacterial attachment to silicone urinary catheters. We show that the flexibility of copolymers can be tuned to match that of the silicone catheter substrate, by copolymerizing these polymers with a lower Tg monomer such that it passes the flexing fatigue tests as coatings upon catheters, that the homopolymers failed. Furthermore, the Tg values of the copolymers are shown to be readily estimated by the Fox equation. The bacterial resistance performance of these copolymers were typically found to be better than the neat silicone or a commercial silver containing hydrogel surface, when the monomer feed contained only 25 v% of the "hit" monomer. The method of initiation (either photo or thermal) was shown not to affect the bacterial resistance of the copolymers. Optimized synthesis conditions to ensure that the correct copolymer composition and to prevent the onset of gelation are detailed.

  12. Synthesis of ciprofloxacin-conjugated poly (L-lactic acid) polymer for nanofiber fabrication and antibacterial evaluation

    Science.gov (United States)

    Parwe, Sharad P; Chaudhari, Priti N; Mohite, Kavita K; Selukar, Balaji S; Nande, Smita S; Garnaik, Baijayantimala

    2014-01-01

    Ciprofloxacin was conjugated with polylactide (PLA) via the secondary amine group of the piperazine ring using PLA and 7-(4-(2-Chloroacetyl) piperazin-1-yl)-1-cyclopropyl-6-fluoro-1, 4-dihydro-4-oxoquinoline-3-carboxylic acid. Zinc prolinate, a biocompatible catalyst was synthesized, characterized, and used in ring opening polymerization of L-lactide. Five different kinds of OH-terminated poly(L-lactide) (two-, three-, four-, six-arm, star-shaped) homopolymers were synthesized by ring opening polymerization of L-lactide in the presence of dodecanol, glycerol, pentaerythritol, dipentaerythritol as initiator and zinc prolinate as a catalyst. The structures of the polymers and conjugates were thoroughly characterized by means of gel permeation chromatography, matrix-assisted laser desorption/ionization – time of flight mass spectrometry, and nuclear magnetic resonance spectroscopy. PLA (molecular weight =100,000) and ciprofloxacin conjugated PLA were used for fabrication of nonwoven nanofiber mat (diameter ranges; 150–400 nm) having pore size (62–102 nm) using electrospinning. The microbiological assessment shows that the release of ciprofloxacin possesses antimicrobial activity. The drug-release behavior of the mat was studied to reveal potential application as a drug delivery system. The result shows that the ciprofloxacin release rates of the PLA conjugate nonwoven nanofiber mat could be controlled by the drug loading content and the release medium. The development of a biodegradable ciprofloxacin system, based on nonwoven nanofiber mat, should be of great interest in drug delivery systems. PMID:24741303

  13. Terminology of Polymers Containing Ionizable or Ionic Groups and of Polymers Containing Ions, VII.3

    Directory of Open Access Journals (Sweden)

    Jarm, V.

    2009-10-01

    Full Text Available The class of ionic polymers has widespread application in many areas of everyday life, in industrial production, and in the processes of living matter. The properties of ionic polymers depend on the polymer structure, and the nature, content, and location of the ionic groups. To clear differences among various ionic polymers, the IUPAC recommendations present 34 definitionsfor the ionomer, polyacid, polybase, polyampholytic polymer, ion-exchange polymer, polybetaine, polyelectrolyte, intrinsically conducting polymer, solid polymer electrolyte, etc

  14. Supramolecular control over thermoresponsive polymers

    Directory of Open Access Journals (Sweden)

    Victor R. de la Rosa

    2016-01-01

    Full Text Available Thermoresponsive polymers facilitate the development of a wide range of applications in multiple areas spanning from construction or water management to lab-on-a-chip technologies and biomedical sciences. The combination of thermoresponsive polymers with supramolecular chemistry, inspired by the molecular mechanisms behind natural systems, is resulting in adaptive and smart materials with unprecedented properties. This work reviews the past advances on the combination of this young field of research with polymer chemistry that is enabling a high level of control on polymer architecture and stimuli-responsiveness in solution. We will discuss how such polymer systems are able to store thermal information, respond to multiple stimuli in a reversible manner, or adapt their morphology on demand, all powered by the synergy between polymer chemistry and supramolecular chemistry.

  15. Biomolecule-functionalized polymer brushes.

    Science.gov (United States)

    Jiang, Hui; Xu, Fu-Jian

    2013-04-21

    Functional polymer brushes have been utilized extensively for the immobilization of biomolecules, which is of crucial importance for the development of biosensors and biotechnology. Recent progress in polymerization methods, in particular surface-initiated atom transfer radical polymerization (ATRP), has provided a unique means for the design and synthesis of new biomolecule-functionalized polymer brushes. This current review summarizes such recent research activities. The different preparation strategies for biomolecule immobilization through polymer brush spacers are described in detail. The functional groups of the polymer brushes used for biomolecule immobilization include epoxide, carboxylic acid, hydroxyl, aldehyde, and amine groups. The recent research activities indicate that functional polymer brushes become versatile and powerful spacers for immobilization of various biomolecules to maximize their functionalities. This review also demonstrates that surface-initiated ATRP is used more frequently than other polymerization methods in the designs of new biomolecule-functionalized polymer brushes.

  16. Polymer brushes under high load.

    Directory of Open Access Journals (Sweden)

    Suzanne M Balko

    Full Text Available Polymer coatings are frequently used to provide repulsive forces between surfaces in solution. After 25 years of design and study, a quantitative model to explain and predict repulsion under strong compression is still lacking. Here, we combine experiments, simulations, and theory to study polymer coatings under high loads and demonstrate a validated model for the repulsive forces, proposing that this universal behavior can be predicted from the polymer solution properties.

  17. Functional Coatings with Polymer Brushes

    OpenAIRE

    König, Meike

    2013-01-01

    The scope of this work is to fathom different possibilities to create functional coatings with polymer brushes. The immobilization of nanoparticles and enzymes is investigated, as well as the affection of their properties by the stimuli-responsiveness of the brushes. Another aspect is the coating of 3D-nanostructures by polymer brushes and the investigation of the resulting functional properties of the hybrid material. The polymer brush coatings are characterized by a variety of microscopic a...

  18. Small angle scattering and polymers

    Energy Technology Data Exchange (ETDEWEB)

    Cotton, J.P. [Laboratoire Leon Brillouin (LLB) - Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France)

    1996-12-31

    The determination of polymer structure is a problem of interest for both statistical physics and industrial applications. The average polymer structure is defined. Then, it is shown why small angle scattering, associated with isotopic substitution, is very well suited to the measurement of the chain conformation. The corresponding example is the old, but pedagogic, measurement of the chain form factor in the polymer melt. The powerful contrast variation method is illustrated by a recent determination of the concentration profile of a polymer interface. (author) 12 figs., 48 refs.

  19. Progress in polymer solar cell

    Institute of Scientific and Technical Information of China (English)

    LI LiGui; LU GuangHao; YANG XiaoNiu; ZHOU EnLe

    2007-01-01

    This review outlines current progresses in polymer solar cell. Compared to traditional silicon-based photovoltaic (PV) technology, the completely different principle of optoelectric response in the polymer cell results in a novel configuration of the device and more complicated photovoltaic generation process. The conception of bulk-heterojunction (BHJ) is introduced and its advantage in terms of morphology is addressed. The main aspects including the morphology of photoactive layer, which limit the efficiency and stability of polymer solar cell, are discussed in detail. The solutions to boosting up both the efficiency and stability (lifetime) of the polymer solar cell are highlighted at the end of this review.

  20. Sustainable polymers from renewable resources.

    Science.gov (United States)

    Zhu, Yunqing; Romain, Charles; Williams, Charlotte K

    2016-12-14

    Renewable resources are used increasingly in the production of polymers. In particular, monomers such as carbon dioxide, terpenes, vegetable oils and carbohydrates can be used as feedstocks for the manufacture of a variety of sustainable materials and products, including elastomers, plastics, hydrogels, flexible electronics, resins, engineering polymers and composites. Efficient catalysis is required to produce monomers, to facilitate selective polymerizations and to enable recycling or upcycling of waste materials. There are opportunities to use such sustainable polymers in both high-value areas and in basic applications such as packaging. Life-cycle assessment can be used to quantify the environmental benefits of sustainable polymers.

  1. POLYMER ELECTROLYTE MEMBRANE FUEL CELLS

    DEFF Research Database (Denmark)

    2001-01-01

    A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various thermopl......A method for preparing polybenzimidazole or polybenzimidazole blend membranes and fabricating gas diffusion electrodes and membrane-electrode assemblies is provided for a high temperature polymer electrolyte membrane fuel cell. Blend polymer electrolyte membranes based on PBI and various...... thermoplastic polymers for high temperature polymer electrolyte fuel cells have also been developed. Miscible blends are used for solution casting of polymer membranes (solid electrolytes). High conductivity and enhanced mechanical strength were obtained for the blend polymer solid electrolytes...... electrolyte membrane by hot-press. The fuel cell can operate at temperatures up to at least 200 °C with hydrogen-rich fuel containing high ratios of carbon monoxide such as 3 vol% carbon monoxide or more, compared to the carbon monoxide tolerance of 10-20 ppm level for Nafion$m(3)-based polymer electrolyte...

  2. Polymer-based solar cells

    Directory of Open Access Journals (Sweden)

    Alex C. Mayer

    2007-11-01

    Full Text Available A significant fraction of the cost of solar panels comes from the photoactive materials and sophisticated, energy-intensive processing technologies. Recently, it has been shown that the inorganic components can be replaced by semiconducting polymers capable of achieving reasonably high power conversion efficiencies. These polymers are inexpensive to synthesize and can be solution-processed in a roll-to-roll fashion with high throughput. Inherently poor polymer properties, such as low exciton diffusion lengths and low mobilities, can be overcome by nanoscale morphology. We discuss polymer-based solar cells, paying particular attention to device design and potential improvements.

  3. Wear of polymers and composites

    CERN Document Server

    Abdelbary, Ahmed

    2015-01-01

    In the field of tribology, the wear behaviour of polymers and composite materials is considered a highly non-linear phenomenon. Wear of Polymers and Composites introduces fundamentals of polymers and composites tribology. The book suggests a new approach to explore the effect of applied load and surface defects on the fatigue wear behaviour of polymers, using a new tribometer and thorough experiments. It discusses effects of surface cracks, under different static and cyclic loading parameters on wear, and presents an intelligent algorithm, in the form of a neural network, to map the relations

  4. Sustainable polymers from renewable resources

    Science.gov (United States)

    Zhu, Yunqing; Romain, Charles; Williams, Charlotte K.

    2016-12-01

    Renewable resources are used increasingly in the production of polymers. In particular, monomers such as carbon dioxide, terpenes, vegetable oils and carbohydrates can be used as feedstocks for the manufacture of a variety of sustainable materials and products, including elastomers, plastics, hydrogels, flexible electronics, resins, engineering polymers and composites. Efficient catalysis is required to produce monomers, to facilitate selective polymerizations and to enable recycling or upcycling of waste materials. There are opportunities to use such sustainable polymers in both high-value areas and in basic applications such as packaging. Life-cycle assessment can be used to quantify the environmental benefits of sustainable polymers.

  5. Polymer Processing and Characterization Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The purpose is to process and evaluate polymers for use in nonlinear optical, conductive and structural Air Force applications. Primary capabilities are extrusion of...

  6. Vegetable oil-derived epoxy monomers and polymer blends: A comparative study with review

    OpenAIRE

    T. P. Schuman; Wang, R.

    2013-01-01

    Glycidyl esters of epoxidized fatty acids derived from soybean oil (EGS) and linseed oil (EGL) have been synthesized to have higher oxirane content, more reactivity and lower viscosity than epoxidized soybean oil (ESO) or epoxidized linseed oil (ELO). The EGS and ESO, for comparison, were used neat and in blends with diglycidyl ether of bisphenol A (DGEBA). Thermosetting resins were fabricated with the epoxy monomers and either BF3 catalyst or anhydride. The curing behaviors, glass transition...

  7. ORGANOSILANE POLYMERS:OXIDATION-CROSSLINKABLE CYCLOTETRAMETHYLENESILYLENE POLYMER AND COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xinghua; Robert West

    1987-01-01

    Polysilane polymers containing cyclotetramethylenesilylene units were synthesized by sodium coupling of diorganodichlorosilanes in toluene. These polymers are soluble in common solvents, can be formed into a variety of shapes by molding, casting, coating or potting. They can be crosslinked by irradiation and oxidation at moderate or room temperature.

  8. Thermoresponsive Polymers for Nuclear Medicine: Which Polymer Is the Best?

    Science.gov (United States)

    Sedláček, Ondřej; Černoch, Peter; Kučka, Jan; Konefal, Rafał; Štěpánek, Petr; Vetrík, Miroslav; Lodge, Timothy P; Hrubý, Martin

    2016-06-21

    Thermoresponsive polymers showing cloud point temperatures (CPT) in aqueous solutions are very promising for the construction of various systems in biomedical field. In many of these applications these polymers get in contact with ionizing radiation, e.g., if they are used as carriers for radiopharmaceuticals or during radiation sterilization. Despite this fact, radiosensitivity of these polymers is largely overlooked to date. In this work, we describe the effect of electron beam ionizing radiation on the physicochemical and phase separation properties of selected thermoresponsive polymers with CPT between room and body temperature. Stability of the polymers to radiation (doses 0-20 kGy) in aqueous solutions increased in the order poly(N-vinylcaprolactam) (PVCL, the least stable) ≪ poly[N-(2,2-difluoroethyl)acrylamide] (DFP) polymer radiotherapeutics and sterilization of biomedical systems, cause significant increase in molecular weight due to cross-linking (except for POX, where this effect is weak). In the case of PVCL irradiated with low doses, the increase in molecular weight induced an increase in the CPT of the polymer. For PNIPAM and DFP, there is strong chain hydrophilization leading to an increase in CPT. From this perspective, POX is the most suitable polymer for the construction of delivery systems that experience exposure to radiation, while PVCL is the least suitable and PNIPAM and DFP are suitable only for low radiation demands.

  9. All Polymer Micropump

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen

    2008-01-01

    of the substrate, the PEDOT is integrated into the non-conductive polymer. The result is a material that retains the good conductivity of PEDOT, but gains the mechanical stability of the substrate. The best results were obtained for PEDOTjPMMA. The new mechanically stable PEDOTjPMMA was micro-patterned using clean...... (ACEO) micropump. The ACEO pump consists of an array of interdigitated small and large PEDOTjPMMA encapsulated in a polyurethane (PUR) channel system. The pumping velocity was detected using fluorescent microspheres and a confocal microscope. The pump characteristics resembled those of pumps based...

  10. Chiral conducting polymers.

    Science.gov (United States)

    Kane-Maguire, Leon A P; Wallace, Gordon G

    2010-07-01

    This critical review describes the preparation and properties of a relatively new class of chiral macromolecules, namely chiral conducting polymers. It focuses in particular on examples based on polypyrrole, polythiophene and polyaniline. They possess remarkable properties, combining not only chirality with electrical conductivity but also the ability to undergo facile redox and pH switching. These unique properties have opened up a range of exciting new potential applications, including as chiral sensors, as novel stationary phases for chiral separations, and as chiral electrodes for electrochemical asymmetric synthesis (153 references).

  11. Polymer Blends. Volume 1

    Science.gov (United States)

    1992-05-01

    PBI/ ULTEM NEAT RESIN MOLDING EVALUATIONS 18 2.1.3 85/15 PBI/ ULTEM COMPOSITE EVALUATIONS 22 2.1.4 FIRST GENERATION SUMMARY 26 2.2 IMPROVED PBI/"BEST...PBI 37 2.2.4 85/15 eCPBI-2/ ULTEM NEAT RESIN EVALUATIONS 42 2.2.5 SECOND GENERATION SUMMARY 45 2.3 IMPROVED PBI/6F POLYIMIDE BLENDS: THIRD GENERATION...PYROMELLITIC DIANHYDRIDE 100 A1.2 REVIEW AND RISK ANALYSIS 105 iv FIGURES FIGURE PAGE # I HIGH PERFORMANCE POLYMER BLENDS PLAN 6 2 PBI/ ULTEM SEPARATION

  12. POLYMERS BEYOND THE YEAR 2000

    Institute of Scientific and Technical Information of China (English)

    Ingolf Buethe

    2000-01-01

    At the turn of the century, the global polymer industry is undergoing the most rapid and dramatic changes in its history. Emerging markets, particularly in Asia, and their polymer consumption are catching up with other parts of the world,creating new business opportunities. Economy of scale, combined with optimized logistic concepts, is becoming a key economic success factor, thus forcing smaller suppliers out of business and creating a major hurdle for newcomers and the introduction of new products. Globalization of polymer customers and cost pressure lead to a consolidation of suppliers and products. Today standard thermoplastics have a dominant position in the market and they will retain this position in future.Engineering thermoplastics are facing growing competition due to the increased efficiency of standard polymers. This leads to a displacement process where standard polymers substitute engineering thermoplastics. Simultaneously engineering polymers are pushing into new markets or applications or displacing materials like glass, wood or metal. The recent history and future trends have a strong impact on R&D activity in the polymer industry. Competition on a global scale and increasing cost pressure are turning innovation into an essential precondition of commercial success, thus determining the objectives of industrial polymer research and development.

  13. Conductive Polymers via Reactive Aligomer.

    Science.gov (United States)

    1987-01-30

    properties are presumably due to the formation of dibenzothiophene units 7 .! 9 NADC-87038-60 and intermolecular crosslinking(1 6). Frommer and...2), 280, (1984). 17. J.E. Frommer and R.R. Chance, "Electrically Conductive Polymers", Encycoedia of Polymer Science and Engineering. V. 5, Second

  14. Homogeneous crystal nucleation in polymers.

    Science.gov (United States)

    Schick, Christoph; Androsch, R; Schmelzer, Juern W P

    2017-07-14

    The pathway of crystal nucleation significantly influences the structure and properties of semi-crystalline polymers. Crystal nucleation is normally heterogeneous at low supercooling, and homogeneous at high supercooling, of the polymer melt. Homogeneous nucleation in bulk polymers has been, so far, hardly accessible experimentally, and was even doubted to occur at all. This topical review summarizes experimental findings on homogeneous crystal nucleation in polymers. Recently developed fast scanning calorimetry, with cooling and heating rates up to 106 K s-1, allows for detailed investigations of nucleation near and even below the glass transition temperature, including analysis of nuclei stability. As for other materials, the maximum homogeneous nucleation rate for polymers is located close to the glass transition temperature. In the experiments discussed here, it is shown that polymer nucleation is homogeneous at such temperatures. Homogeneous nucleation in polymers is discussed in the framework of classical nucleation theory. The majority of our observations are consistent with the theory. The discrepancies may guide further research, particularly experiments to progress theoretical development. Progress in the understanding of homogeneous nucleation is much needed, since most of the modelling approaches dealing with polymer crystallization exclusively consider homogeneous nucleation. This is also the basis for advancing theoretical approaches to the much more complex phenomena governing heterogeneous nucleation. © 2017 IOP Publishing Ltd.

  15. Fifty years of polymer science

    NARCIS (Netherlands)

    Prez, Du Filip; Hoogenboom, Richard; Klumperman, Bert; Meier, Michael; Monteiro, Michael; Müller, Alejandro; Vancso, Julius

    2015-01-01

    The European Polymer Journal (EPJ) has been serving the scientific community for 50 years, which makes it one of the older macromolecular journals with a broad focus. Since its launch 50 years ago, EPJ has provided a distinguished forum for publications in polymer research, including chemistry, phys

  16. Ring closure in actin polymers

    Science.gov (United States)

    Sinha, Supurna; Chattopadhyay, Sebanti

    2017-03-01

    We present an analysis for the ring closure probability of semiflexible polymers within the pure bend Worm Like Chain (WLC) model. The ring closure probability predicted from our analysis can be tested against fluorescent actin cyclization experiments. We also discuss the effect of ring closure on bend angle fluctuations in actin polymers.

  17. Oil and fat absorbing polymers

    Science.gov (United States)

    Marsh, H. E., Jr. (Inventor)

    1977-01-01

    A method is described for forming a solid network polymer having a minimal amount of crosslinking for use in absorbing fats and oils. The polymer remains solid at a swelling ratio in oil or fat of at least ten and provides an oil absorption greater than 900 weight percent.

  18. Supramolecular networks of telechelic polymers

    NARCIS (Netherlands)

    Bohdan, M.A.

    2016-01-01

    This thesis focuses on the fundamental understanding of phenomena associated with the gelation of end-functionalized polymers and the dynamic processes occurring inside of the gel network. To address particular questions we use two types of telechelic polymers, in which the assembly occurs due to th

  19. HIGH TEMPERATURE POLYMER FUEL CELLS

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Qingfeng, Li; He, Ronghuan

    2003-01-01

    This paper will report recent results from our group on polymer fuel cells (PEMFC) based on the temperature resistant polymer polybenzimidazole (PBI), which allow working temperatures up to 200°C. The membrane has a water drag number near zero and need no water management at all. The high working...

  20. Direct Photopatterning of Electrochromic Polymers

    DEFF Research Database (Denmark)

    Jensen, Jacob; Dyer, Aubrey L.; Shen, D. Eric

    2013-01-01

    Propylenedioxythiophene (ProDOT) polymers are synthesized using an oxidative polymerization route that results in methacrylate substituted poly(ProDOTs) having a Mn of 10–20 kDa wherein the methacrylate functionality constitutes from 6 to 60% of the total monomer units. Solutions of these polymer...

  1. Photo-Healable Metallosupramolecular Polymers

    Science.gov (United States)

    2014-01-09

    Ohio Invited Lecture: Structurally Dynamic Polymers as a Route to Stimuli-Responsive Materials Apr. 2013 ACS PMSE /Chinese Chemical Society meeting...Mark Burnworth, Liming Tang, Stuart J. Rowan, Christoph Weder. Reinforcement of Self- Healing Polymer Films with Cellulose Nanowhiskers, ACS PMSE

  2. Polymer dye lasers

    DEFF Research Database (Denmark)

    Balslev, Søren

    2006-01-01

    , elektronstrålelithografi og Röntgenstrålelithografi. Andre polymerer er også blevet formgivet via ”nanoimprint” lithografi for at skabe laserresonatorer. En række lasere, både baseret på et flydende forstærkningsmedium og et faststof forstærkningsrmedium er blevet udviklet. Laserne giver både lys i flere ”modes” og i een......Formålet med dette Ph.D. arbejde har været at udvikle miniaturiserede polymer farvestoflasere, egnet til at blive integreret i mikrochips som også indeholder andre polymerstrukturer – som for eksempel kan findes i ”Laboratorie-på-en-chip” kredsløb. Lasernes funktion skal være at levere lys til...... meget følsomme sensorformål, og at undgå at skulle opliniere eksterne lyskilder til sensorer på polymerchips. En enkelt type gennemsigtig ”resist” (SU-8) er blevet brugt til at udvikle en række laserresonatorer i polymer. ”Resisten” er blevet formgivet via en række lithografiske teknikker: UV lithografi...

  3. Graphene/Polymer Nanocomposites

    Science.gov (United States)

    Macosko, Chris

    2010-03-01

    Graphite has attracted large attention as a reinforcement for polymers due to its ability to modify electrical conductivity, mechanical and gas barrier properties of host polymers and its potentially lower cost than carbon nanotubes. If graphite can be exfoliated into atomically thin graphene sheets, it is possible to achieve the highest property enhancements at the lowest loading. However, small spacing and strong van der Waals forces between graphene layers make exfoliation of graphite via conventional composite manufacturing strategies challenging. Recently, two different approaches to obtain exfoliated graphite prior to blending were reported: thermal treatment (Schniepp et al., JACS 2006) and chemical modification (Stankovich et al., J Mat Chem 2006). Both start from graphite oxide. We will describe and evaluate these exfoliation approaches and the methods used to produce graphene reinforced thermoplastics, particularly polyester, polycarbonate and polyurethane nanocomposites. Three different dispersion methods - melt blending, solution mixing and in-situ polymerization -- are compared. Characterization of dispersion quality is illustrated with TEM, rheology and in electrical conductivity, tensile modulus and gas barrier property improvement.

  4. Synthesis of ciprofloxacin-conjugated poly (L-lactic acid polymer for nanofiber fabrication and antibacterial evaluation

    Directory of Open Access Journals (Sweden)

    Parwe SP

    2014-03-01

    Full Text Available Sharad P Parwe, Priti N Chaudhari, Kavita K Mohite, Balaji S Selukar, Smita S Nande, Baijayantimala Garnaik Polymer Science and Engineering Division, National Chemical Laboratory, Pune, India Abstract: Ciprofloxacin was conjugated with polylactide (PLA via the secondary amine group of the piperazine ring using PLA and 7-(4-(2-Chloroacetyl piperazin-1-yl-1-cyclopropyl-6-fluoro-1, 4-dihydro-4-oxoquinoline-3-carboxylic acid. Zinc prolinate, a biocompatible catalyst was synthesized, characterized, and used in ring opening polymerization of L-lactide. Five different kinds of OH-terminated poly(L-lactide (two-, three-, four-, six-arm, star-shaped homopolymers were synthesized by ring opening polymerization of L-lactide in the presence of dodecanol, glycerol, pentaerythritol, dipentaerythritol as initiator and zinc prolinate as a catalyst. The structures of the polymers and conjugates were thoroughly characterized by means of gel permeation chromatography, matrix-assisted laser desorption/ionization – time of flight mass spectrometry, and nuclear magnetic resonance spectroscopy. PLA (molecular weight =100,000 and ciprofloxacin conjugated PLA were used for fabrication of nonwoven nanofiber mat (diameter ranges; 150–400 nm having pore size (62–102 nm using electrospinning. The microbiological assessment shows that the release of ciprofloxacin possesses antimicrobial activity. The drug-release behavior of the mat was studied to reveal potential application as a drug delivery system. The result shows that the ciprofloxacin release rates of the PLA conjugate nonwoven nanofiber mat could be controlled by the drug loading content and the release medium. The development of a biodegradable ciprofloxacin system, based on nonwoven nanofiber mat, should be of great interest in drug delivery systems. Keywords: zinc prolinate, ciprofloxacin conjugated polylactides, CP-PLA, electrospinning, nonwoven nanofibers, drug release, antibacterial activity, MDR

  5. Soft Confinement for Polymer Solutions

    CERN Document Server

    Oya, Yutaka

    2014-01-01

    As a model of soft confinement for polymers, we investigated equilibrium shapes of a flexible vesicle that contains a phase-separating polymer solution. To simulate such a system, we combined the phase field theory (PFT) for the vesicle and the self-consistent field theory (SCFT) for the polymer solution. We observed a transition from a symmetric prolate shape of the vesicle to an asymmetric pear shape induced by the domain structure of the enclosed polymer solution. Moreover, when a non-zero spontaneous curvature of the vesicle is introduced, a re-entrant transition between the prolate and the dumbbell shapes of the vesicle is observed. This re-entrant transition is explained by considering the competition between the loss of conformational entropy and that of translational entropy of polymer chains due to the confinement by the deformable vesicle. This finding is in accordance with the recent experimental result reported by Terasawa, et al.

  6. Accelerated Characterization of Polymer Properties

    Energy Technology Data Exchange (ETDEWEB)

    R. Wroczynski; l. Brewer; D. Buckley; M. Burrell; R. Potyrailo

    2003-07-30

    This report describes the efforts to develop a suite of microanalysis techniques that can rapidly measure a variety of polymer properties of industrial importance, including thermal, photo-oxidative, and color stability; as well as ductility, viscosity, and mechanical and antistatic properties. Additional goals of the project were to direct the development of these techniques toward simultaneous measurements of multiple polymer samples of small size in real time using non-destructive and/or parallel or rapid sequential measurements, to develop microcompounding techniques for preparing polymers with additives, and to demonstrate that samples prepared in the microcompounder could be analyzed directly or used in rapid off-line measurements. These enabling technologies are the crucial precursors to the development of high-throughput screening (HTS) methodologies for the polymer additives industry whereby the rate of development of new additives and polymer formulations can be greatly accelerated.

  7. Controlled release from recombinant polymers.

    Science.gov (United States)

    Price, Robert; Poursaid, Azadeh; Ghandehari, Hamidreza

    2014-09-28

    Recombinant polymers provide a high degree of molecular definition for correlating structure with function in controlled release. The wide array of amino acids available as building blocks for these materials lend many advantages including biorecognition, biodegradability, potential biocompatibility, and control over mechanical properties among other attributes. Genetic engineering and DNA manipulation techniques enable the optimization of structure for precise control over spatial and temporal release. Unlike the majority of chemical synthetic strategies used, recombinant DNA technology has allowed for the production of monodisperse polymers with specifically defined sequences. Several classes of recombinant polymers have been used for controlled drug delivery. These include, but are not limited to, elastin-like, silk-like, and silk-elastinlike proteins, as well as emerging cationic polymers for gene delivery. In this article, progress and prospects of recombinant polymers used in controlled release will be reviewed.

  8. Grafted polymer under shear flow

    Science.gov (United States)

    Kumar, Sanjiv; Foster, Damien P.; Giri, Debaprasad; Kumar, Sanjay

    2016-04-01

    A self-attracting-self-avoiding walk model of polymer chain on a square lattice has been used to gain an insight into the behaviour of a polymer chain under shear flow in a slit of width L. Using exact enumeration technique, we show that at high temperature, the polymer acquires the extended state continuously increasing with shear stress. However, at low temperature the polymer exhibits two transitions: a transition from the coiled to the globule state and a transition to a stem-flower like state. For a chain of finite length, we obtained the exact monomer density distributions across the layers at different temperatures. The change in density profile with shear stress suggests that the polymer under shear flow can be used as a molecular gate with potential application as a sensor.

  9. Polymer in Agriculture: a Review

    Directory of Open Access Journals (Sweden)

    Francesco Puoci

    2008-01-01

    Full Text Available In agricultural field, polymers are widely used for many applications. Although they were used, in the first time, just as structural materials (inhert polymers, in the last decades functionalized polymers revolutionized the agricultural and food industry with new tools for several applications. Smart polymeric materials and smart delivery systems helped the agricultural industryto combat viruses and other crop pathogens, functionalized polymers were used to increase the efficiency of pesticides and herbicides, allowing lower doses to be used and to indirectly protect the environment through filters or catalysts to reduce pollution and clean-up existing pollutants. This report will review the key aspects of used polymers in agricultural area, highlighting current research in this field and the future impacts they may have.

  10. Electrochemical synthesis of electroconducting polymers

    Directory of Open Access Journals (Sweden)

    Gvozdenović Milica M.

    2014-01-01

    Full Text Available Electroconducting polymers from the group of synthetic metals are extensively investigated due to numerous properties perspective in practical application. These materials may be synthesized by both chemical and electrochemical procedures. Chemical synthesis is suitable when bulk quantities of the polymer are needed and up to date it presents dominant commercial method of producing electroconducting polymers. Nevertheless, electrochemical synthesis has its advantages; it avoids usage of oxidants since conducting polymeric material is obtained at anode upon application of positive potential, leading to increased purity. On the other hand, since the polymer is deposited onto electrode, further electrochemical characterization is facilitated. Owing to actuality of the research in the field this texts aims to describe important aspects of electrochemical synthesis of electroconducting polymers, with special emphasis to polyaniline and polypyrrole. [Projekat Ministarstva nauke Republike Srbije, br. 172046

  11. Mechanisms of Morphology Development and Control in Polymer- Polymer Blends

    Science.gov (United States)

    Macosko, Christopher W.

    1998-03-01

    Polymer-polymer blends continue to be the most important method for achieving optimization of properties in plastics products. Over 30 percent of all plastics are blends. While miscible blends generally give average properties between the components, immiscible blends offer synergistic possibilities such as high modulus with high toughness; high flow with high impact strength or diffusion barriers with good mechanical properties and low cost. The key to performance of these immiscible blends is their morphology. There are several important types of morphology which can lead to valuable property improvement: emulsion - small polymer spheres well dispersed in a polymer matrix. double emulsion - spheres inside spheres which are dispersed in another matrix. microlayer - thin, parallel layers of one polymer in a matrix. cocontinuous - two (or more) continuous, interpenetrating polymer phases. To be economical it is desirable to create these morphologies via melt mixing of powder or pellets in conventional compounding equipment. The melting stage during compounding is very important for morphology development. This presentation will demonstrate the role of melting or softening of each phase as well as their viscosity, elasticity and interfacial tension in morphology development. Interfacial modification with premade block copolymers or reactively formed copolymers can greatly alter morphology formation and stability. Experimental results will be presented which quantify the role of these additives. References to recent work in this area by our group are listed below: DeBrule, M. B., L. Levitt and C.W. Macosko, "The Rheology and Morphology of Layered Polymer Melts in Shear," Soc. Plastics Eng. Tech Papers (ANTEC), 84-89 (1996). Guegan, P., C. W. Macosko, T. Ishizone, A. Hirao and S. Nakahama, "Kinetics of Chain Coupling at Melt Interfaces, Macromol. 27, 4993-4997 (1994). Lee, M. S., T.P. Lodge, and C. W. Macosko, "Can Random Copolymers Serve as Effective Polymeric

  12. Wetting behavior of oleophobic polymer coatings synthesized from fluorosurfactant-macromers.

    Science.gov (United States)

    Howarter, John A; Genson, Kirsten L; Youngblood, Jeffrey P

    2011-06-01

    Architecturally similar monomers were copolymerized with a water-oil discriminate fluorosurfactant to create hydrophilic-oleophobic coatings. Acrylic acid, hydroxyethyl methacrylate, and methyl methacrylate were used as comonomers with the fluorosurfactant macromer. The homopolymers of the selected comonomers are water-soluble, water-swellable, and water-insoluble, respectively, thus coupling the surfactant monomer in varying concentration within polymers of varying hydrophilicity. Wetting behavior of water and hexadecane were examined as a function of copolymer composition, thus revealing critical structure-property relationships for the surfactant-based system. Acrylic acid copolymers and hydroxyethyl methacrylate copolymers both exhibited a hexadecane contact angle which exceeded the water contact angle. This condition predicted an ability to "self-clean" oil-based foulants. The most oleophobic of the self-cleaning copolymers had an advancing hexadecane contact angle of 73° and an advancing water contact angle of 40°. It was determined that the advancing and receding water and hexadecane contact angle response varies montonically for each copolymer type as the surface concentration of the surfactant is varied. Comparing between copolymer types revealed large differences in wetting response. Methyl methacrylate copolymers with 2.8 mol % surfactant had advancing water contact angle 82° and advancing hexadecane contact angle 26°, which is neither oleophobic nor self-cleaning. In contrast, acrylic acid copolymers with 3.1 mol % surfactant had advancing water contact angle of 44° and advancing hexadecane contact angle of 52°, creating a self-cleaning coating. Thus, the nature of the comonomer exerts a greater influence than the surfactant content on the wetting behavior and self-cleaning ability of the final coating.

  13. Polymers – A New Open Access Scientific Journal on Polymer Science

    Directory of Open Access Journals (Sweden)

    Shu-Kun Lin

    2009-12-01

    Full Text Available Polymers is a new interdisciplinary, Open Access scientific journal on polymer science, published by Molecular Diversity Preservation International (MDPI. This journal welcomes manuscript submissions on polymer chemistry, macromolecular chemistry, polymer physics, polymer characterization and all related topics. Both synthetic polymers and natural polymers, including biopolymers, are considered. Manuscripts will be thoroughly peer-reviewed in a timely fashion, and papers will be published, if accepted, within 6 to 8 weeks after submission. [...

  14. Polymer nanoassemblies for cancer treatment and imaging.

    Science.gov (United States)

    Lee, Hyun Jin; Ponta, Andrei; Bae, Younsoo

    2010-12-01

    Amphiphilic polymers represented by block copolymers self-assemble into well-defined nanostructures capable of incorporating therapeutics. Polymer nanoassemblies currently developed for cancer treatment and imaging are reviewed in this article. Particular attention is paid to three representative polymer nanoassemblies: polymer micelles, polymer micellar aggregates and polymer vesicles. Rationales, design and performance of these polymer nanoassemblies are addressed, focusing on increasing the solubility and chemical stability of drugs. Also discussed are polymer nanoassembly formation, the distribution of polymer materials in the human body and applications of polymer nanoassemblies for combined therapy and imaging of cancer. Updates on tumor-targeting approaches, based on preclinical and clinical results are provided, as well as solutions for current issues that drug-delivery systems have, such as in vivo stability, tissue penetration and therapeutic efficacy. These are discussed to provide insights on the future development of more effective polymer nanoassemblies for the delivery of therapeutics in the body.

  15. EDITORIAL: Electroactive polymer materials

    Science.gov (United States)

    Bar-Cohen, Yoseph; Kim, Kwang J.; Ryeol Choi, Hyouk; Madden, John D. W.

    2007-04-01

    Imitating nature's mechanisms offers enormous potential for the improvement of our lives and the tools we use. This field of the study and imitation of, and inspiration from, nature's methods, designs and processes is known as biomimetics. Artificial muscles, i.e. electroactive polymers (EAPs), are one of the emerging technologies enabling biomimetics. Polymers that can be stimulated to change shape or size have been known for many years. The activation mechanisms of such polymers include electrical, chemical, pneumatic, optical and magnetic. Electrical excitation is one of the most attractive stimulators able to produce elastic deformation in polymers. The convenience and practicality of electrical stimulation and the continual improvement in capabilities make EAP materials some of the most attractive among activatable polymers (Bar-Cohen Y (ed) 2004 Electroactive Polymer (EAP) Actuators as Artificial Muscles—Reality, Potential and Challenges 2nd edn, vol PM136 (Bellingham, WA: SPIE Press) pp 1-765). As polymers, EAP materials offer many appealing characteristics that include low weight, fracture tolerance and pliability. Furthermore, they can be configured into almost any conceivable shape and their properties can be tailored to suit a broad range of requirements. These capabilities and the significant change of shape or size under electrical stimulation while being able to endure many cycles of actuation are inspiring many potential possibilities for EAP materials among engineers and scientists in many different disciplines. Practitioners in biomimetics are particularly excited about these materials since they can be used to mimic the movements of animals and insects. Potentially, mechanisms actuated by EAPs will enable engineers to create devices previously imaginable only in science fiction. For many years EAP materials received relatively little attention due to their poor actuation capability and the small number of available materials. In the last fifteen

  16. Conducting Polymer Based Nanobiosensors

    Directory of Open Access Journals (Sweden)

    Chul Soon Park

    2016-06-01

    Full Text Available In recent years, conducting polymer (CP nanomaterials have been used in a variety of fields, such as in energy, environmental, and biomedical applications, owing to their outstanding chemical and physical properties compared to conventional metal materials. In particular, nanobiosensors based on CP nanomaterials exhibit excellent performance sensing target molecules. The performance of CP nanobiosensors varies based on their size, shape, conductivity, and morphology, among other characteristics. Therefore, in this review, we provide an overview of the techniques commonly used to fabricate novel CP nanomaterials and their biosensor applications, including aptasensors, field-effect transistor (FET biosensors, human sense mimicking biosensors, and immunoassays. We also discuss prospects for state-of-the-art nanobiosensors using CP nanomaterials by focusing on strategies to overcome the current limitations.

  17. Protein Polymers and Amyloids

    DEFF Research Database (Denmark)

    Risør, Michael Wulff

    2014-01-01

    , underlining the importance of understanding this relationship. The monomeric C-36 peptide was investigated by liquid-state NMR spectroscopy and found to be intrinsically disordered with minor propensities towards β-sheet structure. The plasticity of such a peptide makes it suitable for a whole range......, is a general hallmark. They also include the α1-antitrypsin deficiency, where disease-causing mutations in the serine protease inhibitor, α1-antitrypsin (α1AT), leads to accumulation of the aberrant protein in the liver of these patients. The native metastable structure of α1AT constitutes a molecular trap...... of this mechanism were investigated through a series of interaction experiments. Despite a very buried location in the native structure, evidence here suggest that the C-terminal tail is labile under slightly destabilizing conditions, providing new detail to this matter. A small infectious polymer unit was also...

  18. Polymer Infiltration Studies

    Energy Technology Data Exchange (ETDEWEB)

    Marchello, J.M.

    1993-06-01

    Significant progress has been made on the preparation of carbon fiber composites using advanced polymer resins during the past three months. Current and ongoing research activities reported herein include: (1) Prepregger Hot Sled Operation; (2) Ribbonizing Powder-Impregnated Towpreg; (3) Textile Composites from Powder-Coated Towpreg: Role of Bulk Factor; and (4) Powder Curtain Prepreg Process. During the coming months research will be directed toward further development of the new powder curtain prepregging method and on ways to customize dry powder towpreg for textile and robotic applications in aircraft part fabrication. Studies of multi-tow powder prepregging and ribbon preparation will be conducted in conjunction with continued development of prepegging technology and the various aspects of composite part fabrication using customized towpreg. Also, work will continue on the analysis of the new solution prepegger.

  19. Protein Polymers and Amyloids

    DEFF Research Database (Denmark)

    Risør, Michael Wulff

    2014-01-01

    Several human disorders are caused by a common general disease mechanism arising from abnormal folding and aggregation of the underlying protein. These include the prevalent dementias like Alzheimer’s and Parkinson’s, where accumulation of protein fibrillar structures, known as amyloid fibrils......, is a general hallmark. They also include the α1-antitrypsin deficiency, where disease-causing mutations in the serine protease inhibitor, α1-antitrypsin (α1AT), leads to accumulation of the aberrant protein in the liver of these patients. The native metastable structure of α1AT constitutes a molecular trap...... that inhibits its target protease through a large conformational change but mutations compromise this function and cause premature structural collapse into hyperstable polymers. Understanding the conformational disorders at a molecular level is not only important for our general knowledge on protein folding...

  20. Polymer optical fiber fuse

    CERN Document Server

    Mizuno, Yosuke; Tanaka, Hiroki; Nakamura, Kentaro

    2013-01-01

    Although high-transmission-capacity optical fibers are in demand, the problem of the fiber fuse phenomenon needs to be resolved to prevent the destruction of fibers. As polymer optical fibers become more prevalent, clarifying their fuse properties has become important. Here, we experimentally demonstrate a fuse propagation velocity of 21.9 mm/s, which is 1 to 2 orders of magnitude slower than that in standard silica fibers. The achieved threshold power density and proportionality constant between the propagation velocity and the power density are respectively 1/186 of and 16.8 times the values for silica fibers. An oscillatory continuous curve instead of periodic voids is formed after the passage of the fuse. An easy fuse termination method is presented herein, along with its potential plasma applications.

  1. Polymer Parametrised Field Theory

    CERN Document Server

    Laddha, Alok

    2008-01-01

    Free scalar field theory on 2 dimensional flat spacetime, cast in diffeomorphism invariant guise by treating the inertial coordinates of the spacetime as dynamical variables, is quantized using LQG type `polymer' representations for the matter field and the inertial variables. The quantum constraints are solved via group averaging techniques and, analogous to the case of spatial geometry in LQG, the smooth (flat) spacetime geometry is replaced by a discrete quantum structure. An overcomplete set of Dirac observables, consisting of (a) (exponentials of) the standard free scalar field creation- annihilation modes and (b) canonical transformations corresponding to conformal isometries, are represented as operators on the physical Hilbert space. None of these constructions suffer from any of the `triangulation' dependent choices which arise in treatments of LQG. In contrast to the standard Fock quantization, the non- Fock nature of the representation ensures that the algebra of conformal isometries as well as tha...

  2. Polymers in Curved Boxes

    CERN Document Server

    Yaman, K; Solis, F J; Witten, T A

    1996-01-01

    We apply results derived in other contexts for the spectrum of the Laplace operator in curved geometries to the study of an ideal polymer chain confined to a spherical annulus in arbitrary space dimension D and conclude that the free energy compared to its value for an uncurved box of the same thickness and volume, is lower when $D < 3$, stays the same when $D = 3$, and is higher when lowers the effective bending elasticity of the walls, and might induce spontaneous symmetry breaking, i.e. bending. (Actually, the above mentioned results show that {\\em {any}} shell in $D = 3$ induces this effect, except for a spherical shell). We compute the contribution of this effect to the bending rigidities in the Helfrich free energy expression.

  3. Self-healing polymers

    Science.gov (United States)

    Klein, Daniel J. (Inventor)

    2011-01-01

    A three dimensional structure fabricated from a self-healing polymeric material, comprising poly(ester amides) obtained from ethylene glycol, azelaic acid and 1,1-aminoundecanoic acid, wherein polymeric material has a melt index above 2.5 g/10 min. as determined by ASTM D1238 at 190.degree. C. and 2.16kg, impact resistance and ductility sufficient to resist cracking and brittle fracture upon impact by a 9 mm bullet fired at a temperature of about 29.degree. C. at subsonic speed in a range from about 800 feet/sec to about 1000 feet/sec. It has been determined that the important factors necessary for self-healing behavior of polymers include sufficient impact strength, control of the degree of crystallinity, low melting point and the ability to instantly melt at impacted area.

  4. Elastic Behavior of Polymer Chains

    Institute of Scientific and Technical Information of China (English)

    Teng Lu; Tao Chen; Hao-jun Liang

    2008-01-01

    The elastic behavior of the polymer chain was investigated in a three-dimensional off-lattice model. We sample more than 109 conformations of each kind of polymer chain by using a Monte Carlo algorithm, then analyze them with the non-Gaussian theory of rubberlike elasticity, and end with a statistical study. Through observing the effect of the chain flexibility and the stretching ratio on the mean-square end-to-end distance,the average energy, the average Helmholtz free energy, the elastic force, the contribution of energy to the elastic force, and the entropy contribution to elastic force of the polymer chain, we find that a rigid polymer chain is much easier to stretch than a flexible polymer chain. Also, a rigid polymer chain will become difficult to stretch only at a quite high stretching ratio because of the effect of the entropy contribution.These results of our simulation calculation may explain some of the macroscopic phenomena of polymer and biomacromolecular elasticity.

  5. Synthetic polymers for solar harvesting.

    Science.gov (United States)

    Ghiggino, Kenneth P; Bell, Toby D M; Hooley, Emma N

    2012-01-01

    Synthetic polymers incorporating appropriate chromophores can act as light harvesting antennae for artificial photosynthetic systems. The photophysical processes occurring in a polymer based on phenylene vinylene have been investigated at the single chain level and in bulk solution to study energy transfer processes. Most single chains of an alternating copolymer of 2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene and 1,4-phenylene vinylene (alt-co-MEH-PPV) dispersed in a transparent polymer matrix act as single chromophore emitters demonstrating that energy transfer is an efficient process in these polymers. However for individual polymer chains there are fluctuations in emission intensity ('blinking') and shifts in emission spectra, decay lifetimes and emission dipole orientation occurring on a time-scale of tens of seconds. Fluorescence blinking also occurs on a sub-millisecond time-scale and follows exponential kinetics, whereas the longer blinking is better described by a power law. These observations can be interpreted as arising from environmental relaxation processes and/or changes in the emitter and demonstrate the wide distribution of photophysical behaviours that can be observed among the individual molecules of a polymer sample. The relevance of these studies to the application of polymer materials for solar harvesting is highlighted.

  6. Carbon dioxide foaming of glassy polymers

    NARCIS (Netherlands)

    Wessling, M.; Borneman, Z.; Boomgaard, van den Th.; Smolders, C.A.

    1994-01-01

    The mechanism of foaming a glassy polymer using sorbed carbon dioxide is studied in detail. A glassy polymer supersaturated with nitrogen forms a microcellular foam, if the polymer is quickly heated above its glass transition temperature. A glassy polymer supersaturated with CO2 forms this foam-like

  7. The Workshop on Conductive Polymers: Final Report

    Science.gov (United States)

    1985-10-01

    Reports are made by groups on: polyacetylene, polyphenylene, polyaniline, and related systems; molecular, crystallographic, and defect structures in conducting polymers; heterocyclic polymers; synthesis of new and improved conducting polymers; future applications possibilities for conducting polymers; and challenges for improved understanding of properties. (DLC)

  8. Migration and sensory evaluation of irradiated polymers

    NARCIS (Netherlands)

    Stoffers, N.H.; Linssen, J.P.H.; Franz, R.; Welle, F.

    2004-01-01

    The effects on ionising irradiation on polymer additives, monomers and polymers themselves have been investigated. Changes of initial concentrations of certain additives and monomers, a change in their specific migration as well as sensory changes of the polymers were examined. Polymer stabilizers s

  9. Carbon nanotube-polymer composite actuators

    Science.gov (United States)

    Gennett, Thomas; Raffaelle, Ryne P.; Landi, Brian J.; Heben, Michael J.

    2008-04-22

    The present invention discloses a carbon nanotube (SWNT)-polymer composite actuator and method to make such actuator. A series of uniform composites was prepared by dispersing purified single wall nanotubes with varying weight percents into a polymer matrix, followed by solution casting. The resulting nanotube-polymer composite was then successfully used to form a nanotube polymer actuator.

  10. Scaling Behaviors of Branched Polymers

    CERN Document Server

    Aoki, H; Kawai, H; Kitazawa, Y; Aoki, Hajime; Iso, Satoshi; Kawai, Hikaru; Kitazawa, Yoshihisa

    2000-01-01

    We study the thermodynamic behavior of branched polymers. We first study random walks in order to clarify the thermodynamic relation between the canonical ensemble and the grand canonical ensemble. We then show that correlation functions for branched polymers are given by those for $\\phi^3$ theory with a single mass insertion, not those for the $\\phi^3$ theory themselves. In particular, the two-point function behaves as $1/p^4$, not as $1/p^2$, in the scaling region. This behavior is consistent with the fact that the Hausdorff dimension of the branched polymer is four.

  11. Physical properties of polymers handbook

    CERN Document Server

    2007-01-01

    This book offers concise information on the properties of polymeric materials, particularly those most relevant to physical chemistry and chemical physics. Extensive updates and revisions to each chapter include eleven new chapters on novel polymeric structures, reinforcing phases in polymers, and experiments on single polymer chains. The study of complex materials is highly interdisciplinary, and new findings are scattered among a large selection of scientific and engineering journals. This book brings together data from experts in the different disciplines contributing to the rapidly growing area of polymers and complex materials.

  12. Turbulence in dilute polymer solutions

    Science.gov (United States)

    Liberzon, A.; Guala, M.; Lüthi, B.; Kinzelbach, W.; Tsinober, A.

    2005-03-01

    The work reported below is a comparative study of the properties of turbulence with weak mean flow in a Newtonian fluid and in a dilute polymer solution with an emphasis on the small scale phenomena. The main tool used is a three-dimensional particle tracking system allowing to measure and follow in a Lagrangian manner the field of velocities, as well as velocity derivatives, and thus vorticity, strain, and a variety of related and dynamically significant quantities. The comparison of data from the two flows allows to directly observe the influence of polymers on these quantities as well as the evolution of material elements in the presence of polymers.

  13. Thermoresponsive Polymers for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Theoni K. Georgiou

    2011-08-01

    Full Text Available Thermoresponsive polymers are a class of “smart” materials that have the ability to respond to a change in temperature; a property that makes them useful materials in a wide range of applications and consequently attracts much scientific interest. This review focuses mainly on the studies published over the last 10 years on the synthesis and use of thermoresponsive polymers for biomedical applications including drug delivery, tissue engineering and gene delivery. A summary of the main applications is given following the different studies on thermoresponsive polymers which are categorized based on their 3-dimensional structure; hydrogels, interpenetrating networks, micelles, crosslinked micelles, polymersomes, films and particles.

  14. Bioderadable Polymers in Food Packaging

    Directory of Open Access Journals (Sweden)

    P.A.Pawar

    2013-01-01

    Full Text Available In recent years, there has been a marked increase in the interest in use of biodegradable materials in packaging. The principal function of packaging is protection and preservation of food from external contamination. This function involves retardation of deterioration, extension of shelf life, and maintenance of quality and safety of packaged food. Biodegradable polymers are the one which fulfill all these functions without causing any threat to the environment. The belief is that biodegradable polymer materials will reduce the need for synthetic polymer production (thus reducing pollution at a low cost, thereby producing a positive effect both environmentally and economically.

  15. Physics of photorefraction in polymers

    CERN Document Server

    West, Dave

    2004-01-01

    Photorefractive polymer composites are an unusually sensitive class of photopolymers. Physics of Photorefraction in Polymers describes our current understanding of the physical processes that produce a photorefractive effect in key composite materials. Topics as diverse as charge generation, dispersive charge transport, charge compensation and trapping, molecular diffusion, organic composite structure, and nonlinear optical wave coupling are all developed from a physical perspective. Emphasis is placed on explaining how these physical processes lead to observable properties of the polymers, and the authors discuss various applications, including holographic archiving.

  16. Multilayer Electroactive Polymer Composite Material

    Science.gov (United States)

    Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Holloway, Nancy M. (Inventor); Draughon, Gregory K. (Inventor)

    2011-01-01

    An electroactive material comprises multiple layers of electroactive composite with each layer having unique dielectric, electrical and mechanical properties that define an electromechanical operation thereof when affected by an external stimulus. For example, each layer can be (i) a 2-phase composite made from a polymer with polarizable moieties and an effective amount of carbon nanotubes incorporated in the polymer for a predetermined electromechanical operation, or (ii) a 3-phase composite having the elements of the 2-phase composite and further including a third component of micro-sized to nano-sized particles of an electroactive ceramic incorporated in the polymer matrix.

  17. Statistical properties of curved polymer

    Indian Academy of Sciences (India)

    Surya Kanta Ghosh; Anirban Sain

    2008-08-01

    Intrinsic curvature of biopolymers is emerging as an essential feature in various biological phenomena. Examples of polymers with intrinsic curvature are microtubule in eukaryotic cells or FtsZ filaments in prokaryotic cells. We consider the general model for polymers with intrinsic curvature. We aim to study both equilibrium and dynamic properties of such polymers. Here we report preliminary results on the equilibrium distribution function $P({\\mathbf{R}})$ of the end-to-end distance ${\\mathbf{R}}$. We employ transfer matrix method for this study.

  18. Principles of polymer processing modelling

    Directory of Open Access Journals (Sweden)

    Agassant Jean-François

    2016-01-01

    Full Text Available Polymer processing involves three thermo-mechanical stages: Plastication of solid polymer granules or powder to an homogeneous fluid which is shaped under pressure in moulds or dies and finally cooled and eventually drawn to obtain the final plastic part. Physical properties of polymers (high viscosity, non-linear rheology, low thermal diffusivity as well as the complex shape of most plastic parts make modelling a challenge. Several examples (film blowing extrusion dies, injection moulding, blow moulding are presented and discussed.

  19. Method for bonding a thermoplastic polymer to a thermosetting polymer component

    NARCIS (Netherlands)

    Van Tooren, M.J.L.

    2012-01-01

    The invention relates to a method for bonding a thermoplastic polymer to a thermosetting polymer component, the thermoplastic polymer having a melting temperature that exceeds the curing temperature of the thermosetting polymer. The method comprises the steps of providing a cured thermosetting polym

  20. Crosslinked polymer nanoparticles containing single conjugated polymer chains.

    Science.gov (United States)

    Ponzio, Rodrigo A; Marcato, Yésica L; Gómez, María L; Waiman, Carolina V; Chesta, Carlos A; Palacios, Rodrigo E

    2017-03-29

    Conjugated polymer nanoparticles are widely used in fluorescent labeling and sensing, as they have mean radii between 5 and 100 nm, narrow size dispersion, high brightness, and are photochemically stable, allowing single particle detection with high spatial and temporal resolution. Highly crosslinked polymers formed by linking individual chains through covalent bonds yield high-strength rigid materials capable of withstanding dissolution by organic solvents. Hence, the combination of crosslinked polymers and conjugated polymers in a nanoparticulated material presents the possibility of interesting applications that require the combined properties of constituent polymers and nanosized dimension. In the present work, F8BT@pEGDMA nanoparticles composed of poly(ethylene glycol dimethacrylate) (pEGDMA; a crosslinked polymer) and containing the commercial conjugated polymer poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) were synthesized and characterized. Microemulsion polymerization was applied to produce F8BT@pEDGMA particles with nanosized dimensions in a ∼25% yield. Photophysical and size distribution properties of F8BT@pEDGMA nanoparticles were evaluated by various methods, in particular single particle fluorescence microscopy techniques. The results demonstrate that the crosslinking/polymerization process imparts structural rigidity to the F8BT@pEDGMA particles by providing resistance against dissolution/disintegration in organic solvents. The synthesized fluorescent crosslinked nanoparticles contain (for the most part) single F8BT chains and can be detected at the single particle level, using fluorescence microscopy, which bodes well for their potential application as molecularly imprinted polymer fluorescent nanosensors with high spatial and temporal resolution.