WorldWideScience

Sample records for excited polymers polyvinyl

  1. Crosslinked poly(vinyl alcohol hydrogels for wound dressing applications: A review of remarkably blended polymers

    Directory of Open Access Journals (Sweden)

    Elbadawy A. Kamoun

    2015-01-01

    Full Text Available A series of excellent poly(vinyl alcohol (PVA/polymers blend hydrogel were reviewed using different crosslinking types to obtain proper polymeric dressing materials, which have satisfied biocompatibility and sufficient mechanical properties. The importance of biodegradable–biocompatible synthetic polymers such as PVA, natural polymers such as alginate, starch, and chitosan or their derivatives has grown significantly over the last two decades due to their renewable and desirable biological properties. The properties of these polymers for pharmaceutical and biomedical application needs have attracted much attention. Thus, a considered proportion of the population need those polymeric medical applications for drug delivery, wound dressing, artificial cartilage materials, and other medical purposes, where the pressure on alternative polymeric devices in all countries became substantial. The review explores different polymers which have been blended previously in the literature with PVA as wound dressing blended with other polymeric materials, showing the feasibility, property change, and purpose which are behind the blending process with PVA.

  2. Synthesis and dielectric studies of polyorthotoluidine-polyvinyl pyrrolidone conducting polymer composites

    Science.gov (United States)

    Himanshu, A. K.; Bahuguna, Rajni; Ray, D. K.; Bandyopadyayay, S. K.; Sinha, T. P.

    2013-02-01

    The intrinsically conducting polymer, polyorthotoluidine (POT) has been synthesized by chemical polymerization process with the help of water-soluble support polymer polyvinyl pyrrolidone (PVP)). The dielectric measurement of POT-PVP was measured in the temperature range from 308-398 K at frequency 10 kHz. The temperature dependent data has been analyzed in the framework of dielectric permittivity, loss tangent and ac conductivity. Above the temperature 345 K, conductivity shows weak temperature dependence. This is an important feature with respect to technological applications of POT-PVP as an electro-inactive material at high temperature.

  3. Reconstitution of cytochrome c oxidase in phospholipid vesicles containing polyvinylic polymers.

    Science.gov (United States)

    Sarti, P; Antonini, G; Malatesta, F; Vallone, B; Villaschi, S; Brunori, M; Hider, R C; Hamed, K

    1989-01-01

    Cytochrome c oxidase was reconstituted in phospholipid vesicles in the presence of highly hydrophobic poly(vinyl alkanoate) polymers. Electron-microscopy observations demonstrated that polymer interaction with the lipid phase induces vesicles to adopt smaller diameters than those typical of standard proteoliposomes. Functional characterization of these polymer-proteoliposome structures indicates that the reconstitution of the enzyme proceeds efficiently without causing either scrambling of the protein orientation in the membrane or loss of respiratory control. A clear dependence of respiratory control ratio on vesicle size was also demonstrated, which is in agreement with a previous model proposed for control of activity of cytochrome c oxidase vesicles [Brunori, Sarti, Colosimo, Antonini, Malatesta, Jones & Wilson (1985) EMBO J. 4, 2365-2368]. Images Fig. 2. PMID:2539096

  4. Identification of excited states in conjugated polymers

    CERN Document Server

    Hartwell, L J

    2003-01-01

    This thesis reports quasi steady state photoinduced absorption measurements from three conjugated polymers: polypyridine (PPy), polyfluorene (PFO) and the emeraldine base (EB) form of polyaniline. The aim of these experiments was to determine the nature of the photoexcited states existing in these materials in the millisecond time domain, as this has important consequences for the operation of real devices manufactured using these materials. The results from the photoinduced absorption experiments are closely compared with published results from pulse radiolysis experiments. In all cases there is very good correspondence between the two data sets, which has enabled the photoexcited states to be assigned with a high degree of confidence. Quasi steady-state photoinduced absorption involves the measurement of the change in absorption of a material in response to optical excitation with a laser beam. The changes in absorption are small, so a instrument was developed and optimised for each different sample. Lock-i...

  5. Self-supported fibrin-polyvinyl alcohol interpenetrating polymer networks: an easily handled and rehydratable biomaterial.

    Science.gov (United States)

    Bidault, Laurent; Deneufchatel, Marie; Vancaeyzeele, Cédric; Fichet, Odile; Larreta-Garde, Véronique

    2013-11-11

    A fibrin hydrogel at physiological concentration (5 mg/mL) was associated with polyvinyl alcohol (PVA) inside an interpenetrating polymer networks (IPN) architecture. Previously, PVA has been modified with methacrylate functions in order to cross-link it by free-radical polymerization. The fibrin network was synthesized by the enzymatic hydrolysis of fibrinogen by thrombin. The resulting self-supported materials simultaneously exhibit the properties of the fibrin hydrogel and those of the synthetic polymer network. Their storage modulus is 50-fold higher than that of the fibrin hydrogel and they are completely rehydratable. These materials are noncytotoxic toward human fibroblast and the fibrin present on the surface of PVAm-based IPNs favors cell development.

  6. Quaternized poly(vinyl alcohol)/alumina composite polymer membranes for alkaline direct methanol fuel cells

    Science.gov (United States)

    Yang, Chun-Chen; Chiu, Shwu-Jer; Chien, Wen-Chen; Chiu, Sheng-Shin

    The quaternized poly(vinyl alcohol)/alumina (designated as QPVA/Al 2O 3) nanocomposite polymer membrane was prepared by a solution casting method. The characteristic properties of the QPVA/Al 2O 3 nanocomposite polymer membranes were investigated using thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), micro-Raman spectroscopy, and AC impedance method. Alkaline direct methanol fuel cell (ADMFC) comprised of the QPVA/Al 2O 3 nanocomposite polymer membrane were assembled and examined. Experimental results indicate that the DMFC employing a cheap non-perfluorinated (QPVA/Al 2O 3) nanocomposite polymer membrane shows excellent electrochemical performances. The peak power densities of the DMFC with 4 M KOH + 1 M CH 3OH, 2 M CH 3OH, and 4 M CH 3OH solutions are 28.33, 32.40, and 36.15 mW cm -2, respectively, at room temperature and in ambient air. The QPVA/Al 2O 3 nanocomposite polymer membranes constitute a viable candidate for applications on alkaline DMFC.

  7. A new nanocomposite polymer electrolyte based on poly(vinyl alcohol) incorporating hypergrafted nano-silica

    KAUST Repository

    Hu, Xian-Lei

    2012-01-01

    Solid-state nanocomposite polymer electrolytes based on poly(vinyl alcohol)(PVA) incorporating hyperbranched poly(amine-ester) (HBPAE) grafted nano-silica (denoted as SiO2-g-HBPAE) have been prepared and investigated. Through surface pretreatment of nanoparticles, followed by Michael-addition and a self-condensation process, hyperbranched poly(amine-ester) was directly polymerized from the surface of nano-silica. Then the hypergrafted nanoparticles were added to PVA matrix, and blended with lithium perchlorate via mold casting method to fabricate nanocomposite polymer electrolytes. By introducing hypergrafted nanoparticles, ionic conductivity of solid composite is improved significantly at the testing temperature. Hypergrafted nano-silica may act as solid plasticizer, promoting lithium salt dissociation in the matrix as well as improving segmental motion of matrix. In addition, tensile testing shows that such materials are soft and tough even at room temperature. From the dielectric spectra of nanocomposite polymer electrolyte as the function of temperature, it can be deduced that Arrhenius behavior appears depending on the content of hypergrafted nano-silica and concentration of lithium perchlorate. At a loading of 15 wt% hypergrafted nano-silica and 54 wt% lithium perchlorate, promising ionic conductivities of PVA nanocomposite polymer electrolyte are achieved, about 1.51 × 10 -4 S cm-1 at 25 °C and 1.36 × 10-3 S cm-1 at 100 °C. © The Royal Society of Chemistry.

  8. Evaluation of polyvinyl alcohols as mucoadhesive polymers for mucoadhesive buccal tablets prepared by direct compression.

    Science.gov (United States)

    Ikeuchi-Takahashi, Yuri; Ishihara, Chizuko; Onishi, Hiraku

    2017-09-01

    The purpose of the present work was to evaluate polyvinyl alcohols (PVAs) as a mucoadhesive polymer for mucoadhesive buccal tablets prepared by direct compression. Various polymerization degree and particle diameter PVAs were investigated for their usability. The tensile strength, in vitro adhesive force, and water absorption properties of the tablets were determined to compare the various PVAs. The highest values of the tensile strength and the in vitro adhesive force were observed for PVAs with a medium viscosity and small particle size. The optimal PVA was identified by a factorial design analysis. Mucoadhesive tablets containing the optimal PVA were compared with carboxyvinyl polymer and hydroxypropyl cellulose formulations. The optimal PVA gives a high adhesive force, has a low viscosity, and resulted in relatively rapid drug release. Formulations containing carboxyvinyl polymer had high tensile strengths but short disintegration times. Higher hydroxypropyl cellulose concentration formulations had good adhesion forces and very long disintegration times. We identified the optimal characteristics of PVA, and the usefulness of mucoadhesive buccal tablets containing this PVA was suggested from their formulation properties.

  9. Energy transfer (In3+ → Eu3+) based Polyvinyl Alcohol polymer composites for bright red luminescence

    Science.gov (United States)

    Kumar, K. Naveen; Vijayalakshmi, L.; Kim, Jong Su; Shim, Jaesool; Cho, Migyung; Kang, Misook; Gupta, Bipin Kumar

    2017-08-01

    A prominent sensitization effect of In3+ ions is observed in In3++Eu3+: PVA polymer composites under UV excitation. Consequently, it enhances the red emission performance of Eu3+ ions in PVA system. We have successfully synthesized Eu3+: PVA, In3+: PVA and In3++Eu3+: PVA polymer films by traditional solution casting method. The structural and ion-polymer interaction studies have been analyzed from XRD and FTIR spectral profiles. Eu3+ doped PVA polymer composites are exhibited a red emission at 619 nm (5D0→7F2) under 396 nm (7F0→5L6) of excitation. Upon co-doping with In3+ ions in different concentrations to the Eu3+: PVA polymer film, it exhibits predominant red emission than singly doped Eu3+: PVA under 396 nm of excitation due to energy migration from In3+ to Eu3+. Successful emission photons of In3+ ions are collectively absorbed by the Eu3+ ions which lead the improvement of red emission. Optimized sensitization concentration of the In3+ ions has been found to be 0.01 wt%. Possible energy migration phenomenon is elucidated by several fluorescent dynamics. The energy transfer process is substantiated by lifetime decay analysis and overlapped spectral studies. The Commission International de I-Eclairage chromaticity coordinates were calculated. The quantum efficiencies of the Eu3+ ions and In3+ ions in singly doped and co-doped polymer systems have been evaluated. From these results, these co-doped In3++Eu3+: PVA composite polymer films might be proposed as encouraging candidates for bright red fluorescent materials for several photonic applications.

  10. Radiation preparation of drug carriers based polyacrylic acid (PAAc) using poly(vinyl pyrrolidone) (PVP) as a template polymer

    Science.gov (United States)

    Abd El-Rehim, H. A.; Hegazy, E. A.; Khalil, F. H.; Hamed, N. A.

    2007-01-01

    The present study deals with the radiation synthesis of stimuli response hydrophilic polymers from polyacrylic acid (PAAc). To maintain the property of PAAc and control the water swellibility for its application as a drug delivery system, radiation polymerization of AAc in the presence of poly(vinyl pyrrolidone) (PVP) as a template polymer was carried out. Characterization of the prepared PAA/PVP inter-polymer complex was investigated by determining gel content, swelling property, hydrogel microstructure and the release rate of caffeine as a model drug. The release rate of caffeine from the PAA/PVP inter-polymer complexes showed pH-dependency, and seemed to be mainly controlled by the dissolution rate of the complex above a p Ka of PAAc. The prepared inter-polymer complex could be used for application as drug carriers.

  11. Radiation preparation of drug carriers based polyacrylic acid (PAAc) using poly(vinyl pyrrolidone) (PVP) as a template polymer

    Energy Technology Data Exchange (ETDEWEB)

    Abd El-Rehim, H.A. [National Center for Radiation Research and Technology, Poymer, 3-Ahmed El-Zomor, P.O. Box 29, Cairo, Naser City (Egypt)]. E-mail: ha_rehim@hotmail.com; Hegazy, E.A. [National Center for Radiation Research and Technology, Poymer, 3-Ahmed El-Zomor, P.O. Box 29, Cairo, Naser City (Egypt); Khalil, F.H. [National Center for Radiation Research and Technology, Poymer, 3-Ahmed El-Zomor, P.O. Box 29, Cairo, Naser City (Egypt); Hamed, N.A. [National Center for Radiation Research and Technology, Poymer, 3-Ahmed El-Zomor, P.O. Box 29, Cairo, Naser City (Egypt)

    2007-01-15

    The present study deals with the radiation synthesis of stimuli response hydrophilic polymers from polyacrylic acid (PAAc). To maintain the property of PAAc and control the water swellibility for its application as a drug delivery system, radiation polymerization of AAc in the presence of poly(vinyl pyrrolidone) (PVP) as a template polymer was carried out. Characterization of the prepared PAA/PVP inter-polymer complex was investigated by determining gel content, swelling property, hydrogel microstructure and the release rate of caffeine as a model drug. The release rate of caffeine from the PAA/PVP inter-polymer complexes showed pH-dependency, and seemed to be mainly controlled by the dissolution rate of the complex above a pK {sub a} of PAAc. The prepared inter-polymer complex could be used for application as drug carriers.

  12. Poly(vinyl alcohol)-based polymer electrolyte membranes for direct methanol fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Higa, Mitsuru, E-mail: mhiga@yamaguchi-u.ac.j [Graduate School of Science and Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube-city, Yamaguchi 755-8611 (Japan); Sugita, Mikinori; Maesowa, Shin-ichi; Endo, Nobutaka [Graduate School of Science and Engineering, Yamaguchi University, 2-16-1 Tokiwadai, Ube-city, Yamaguchi 755-8611 (Japan)

    2010-01-25

    We have prepared polymer electrolyte membranes (PEMs) from poly(vinyl alcohol) (PVA) and modified PVA polyanion containing 2 or 4 mol% of 2-methyl-1-propanesulfonic acid (AMPS) groups as a copolymer. The PEMs of various AMPS content and cross-linking conditions were prepared to determine the effect of AMPS content and cross-linking conditions on PEM properties. Proton conductivity and permeability of methanol through the PEMs increased with increasing AMPS content, C{sub AMPS}, and with decreasing cross-linker concentration, C{sub GA}, because of the increase in the water content. The permeability coefficient of methanol through the PEM prepared under the conditions of C{sub AMPS} = 2.7 mol% and C{sub GA} = 0.35 vol% was about 30 times lower than that of Nafion 117 under the same measurement conditions. The proton permselectivity of the PEM, which is defined as the ratio of the proton conductivity to the permeability coefficient of methanol, gave a maximum value of 66 x 10{sup 3} S cm{sup -3} s. The value is about three times higher than that of Nafion 117.

  13. Safety of the proposed amendment of the specifications for the food additive polyvinyl alcohol‐polyethylene glycol‐graft‐co‐polymer (E 1209)

    National Research Council Canada - National Science Library

    Mortensen, Alicja; Aguilar, Fernando; Crebelli, Riccardo; Di Domenico, Alessandro; Dusemund, Birgit; Frutos, Maria Jose; Galtier, Pierre; Gundert‐Remy, Ursula; Lambré, Claude; Leblanc, Jean‐Charles; Lindtner, Oliver; Moldeus, Peter; Mosesso, Pasquale; Parent‐Massin, Dominique; Oskarsson, Agneta; Stankovic, Ivan; Waalkens‐Berendsen, Ine; Woutersen, Rudolf Antonius; Wright, Matthew; Younes, Maged; Rincon, Ana Maria; Tard, Alexandra; Gott, David

    2017-01-01

    The European Commission asked EFSA to provide a scientific opinion on the request for a modification of the EU specifications for polyvinyl alcohol‐polyethylene glycol‐ graft ‐co‐polymer ( PVA ‐ PEG graft ‐co‐polymer) (E 1209...

  14. Synthesis and characterization of polyvinyl alcohol copolymer/phosphomolybdic acid-based crosslinked composite polymer electrolyte membranes

    Science.gov (United States)

    Anis, Arfat; Banthia, A. K.; Bandyopadhyay, S.

    Polymer electrolyte membrane fuel cells (PEMFCs) are very promising as future energy source due to their high-energy conversion efficiency and will help to solve the environmental concerns of energy production. Polymer electrolyte membrane (PEM) is recognised as the key element for an efficient PEMFC. Chemically crosslinked composite membranes consisting of a poly(vinyl alcohol-co-vinyl acetate-co-itaconic acid) (PVACO) and phosphomolybdic acid (PMA) have been prepared by solution casting and evaluated as proton conducting polymer electrolytes. The proton conductivity of the membranes is investigated as a function of PMA composition, crosslinking density and temperature. The membranes have also been characterized by FTIR spectroscopy, TGA, AFM and TEM. The proton conductivity of the composite membranes is of the order of 10 -3 S cm -1 and shows better resistance to methanol permeability than Nafion 117 under similar measurement conditions.

  15. Polymer filters for ultraviolet-excited integrated fluorescence sensing

    Science.gov (United States)

    Dandin, Marc; Abshire, Pamela; Smela, Elisabeth

    2012-09-01

    Optical filters for blocking ultraviolet (UV) light were fabricated by doping various polymer hosts with a UV absorbing chromophore. The polymers were polydimethylsiloxane (PDMS), a silicone elastomer frequently used in microfluidics, SU-8, a photopatternable epoxy, and Humiseal 1B66, an acrylic coating used for moisture protection of integrated circuits. The chromophore was 2-(2‧-hydroxy-5‧-methylphenyl) benzotriazole (BTA), which has a high extinction coefficient between 300 nm and 400 nm. We demonstrate filters 5 µm thick that exhibit high ultraviolet rejection (nearly -40 dB at 342 nm) yet pass visible light (near 0 dB above 400 nm), making them ideal for ultraviolet-excited fluorescence sensing within microsystems. The absorbance of the BTA depended on the host polymer. These filters are promising for integrated fluorescence spectroscopy in bioanalytical platforms because they can be patterned by dry etching, molding or exposure to ultraviolet light.

  16. A direct borohydride fuel cell based on poly(vinyl alcohol)/hydroxyapatite composite polymer electrolyte membrane

    Science.gov (United States)

    Yang, Chun-Chen; Li, Yingjeng James; Chiu, Shwu-Jer; Lee, Kuo-Tong; Chien, Wen-Chen; Huang, Ching-An

    A new poly(vinyl alcohol)/hydroxyapatite (PVA/HAP) composite polymer membrane was synthesized using a solution casting method. Alkaline direct borohydride fuel cells (DBFCs), consisting of an air cathode based on MnO 2/C inks on Ni-foam, anodes based on PtRu black and Au catalysts on Ni-foam, and the PVA/HAP composite polymer membrane, were assembled and investigated for the first time. It was demonstrated that the alkaline direct borohydride fuel cell comprised of this low-cost PVA/HAP composite polymer membrane showed good electrochemical performance. As a result, the maximum power density of the alkaline DBFC based on the PtRu anode (45 mW cm -2) proved higher than that of the DBFC based on the Au anode (33 mW cm -2) in a 4 M KOH + 1 M KBH 4 solution at ambient conditions. This novel PVA/HAP composite polymer electrolyte membrane with high ionic conductivity at the order of 10 -2 S cm -1 has great potential for alkaline DBFC applications.

  17. Thermal and transport properties of the polymer electrolyte based on poly(vinyl alcohol)-KOH-H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, I. [Universidad del Valle, Cali (Colombia). Departamento de Mat. y Fisica; Castillo, R.; Vargas, R.A. [Universidad Tec. del Choco, Quibdo (Colombia). Departamento de Fisica

    2003-06-30

    In this work we report the preparation of a series of alkaline solid electrolyte membranes, based on poly(vinyl alcohol) (PVOH), potassium hydroxide (KOH) and water (PVOH-KOH-H{sub 2}O). They were characterized by electrical conductivity measurements using impedance spectroscopy (EIS), by thermal measurements, using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The most conducting membranes were composed of 45% PVOH, 15% of KOH and 40% wt. of water whose conductivity reaches the value of 2.3x10{sup -3} S cm{sup -1} at room temperature. Temperature dependence of conductivity was found to follow an Arrhenius type behavior rather than the free volume type behavior associated with ion transport mechanism on polymer motion. The conducting phases are established between the observed glass transition of the blends at about 190 K up to where the water content in the sample is completely dehydrated, that is to say, 450 K. The effect of the humidity on the electrolytic characteristics of a cell M / Polymer / M (where M is stainless steel, silver) is quite remarkable. Changes in the conductivity of the polymer at room temperature between 1x10{sup -5} and 2.3x10{sup -3} S cm{sup -1} when the relative humidity changes between the 25 and 85%, respectively, have been observed. The results are explained in terms of the plastification effects of water on the polymer and the presence of a (KOH/H{sub 2}O) separated phase in the polymer. This new alkaline solid electrolyte is interesting from the point of view of its potential application as humidity sensor or electrolytic separator in alkaline batteries. (author)

  18. Inference of polymer adsorption from electrical double layer measurements : the silver iodide-polyvinyl alcohol system

    NARCIS (Netherlands)

    Koopal, L.K.

    1978-01-01

    The purpose of this study was to investigate how the double layer properties of charged particles are modified by the presence of adsorbed polymer molecules and to obtain information on the conformation of the polymer layer from the observed alterations in the double layer

  19. Development of an anti-insect sachet using a polyvinyl alcohol-cinnamon oil polymer strip against Plodia interpunctella.

    Science.gov (United States)

    Jo, Heon-Joo; Park, Ki-Moon; Min, Sea C; Na, Ja Hyun; Park, Ki Hwan; Han, Jaejoon

    2013-11-01

    Plodia interpunctella is a major storage pest that penetrates into food packaging and causes serious economic losses, as well as posing health risks. The goal of this study was to develop effective anti-insect polymer strips against P. interpunctella by using plant essential oil (EO) and polyvinyl alcohol (PVA). The EO of cinnamon (Cinnamomum zeylanicum, CO) bark was used as an insect repellent, and fumigant mortality and the repellent activity of CO were measured to evaluate subsistent anti-insect properties through newly designed traps. Repellent activity was also examined with several foods to simulate the storage environment. The mortality rate with CO after fumigation for 120 h was 63%. In the repellent assay, CO-treated strips, but not control strips, effectively repelled P. interpunctella in both "with foods" and "without foods" groups. A PVA-CO strip sachet (PCO sachet) was developed to control the volatility of CO, and the PCO sachet demonstrated robust repellent activity. The loading contents of CO at the center and edges of strips were 39.41% and 39.59%, respectively, and through the results of FT-IR, it inferred that CO was physically diffused in the PVA polymer matrix, not forming chemical bonds. In a release test using a gas chromatography, the PCO sachet showed remarkable controlled release of CO. These results demonstrate that the anti-insect effects of CO can be maintained throughout the distribution and storage periods of foods using PCO sachets. © 2013 Institute of Food Technologists®

  20. Chromo- and fluorophoric water-soluble polymers and silica particles by nucleophilic substitution reaction of poly(vinyl amine

    Directory of Open Access Journals (Sweden)

    Katja Hofmann

    2010-07-01

    Full Text Available Novel chromophoric and fluorescent carbonitrile-functionalized poly(vinyl amine (PVAm and PVAm/silica particles were synthesized by means of nucleophilic aromatic substitution of 8-oxo-8H-acenaphtho[1,2-b]pyrrol-9-carbonitrile (1 with PVAm in water. The water solubility of 1 has been mediated by 2,6-O-β-dimethylcyclodextrin or by pre-adsorption onto silica particles. Furthermore, 1 was converted with isopropylamine into the model compound 1-M. All new compounds were characterized by NMR, FTIR, UV–vis and fluorescence spectroscopy. The solvent-dependent UV–vis absorption and fluorescence emission band positions of the model compound and the carbonitrile-functionalized PVAm were studied and interpreted using the empirical Kamlet–Taft solvent parameters π* (dipolarity/polarizability, α (hydrogen-bond donating capacity and β (hydrogen-accepting ability in terms of the linear solvation energy relationship (LSER. The solvent-independent regression coefficients a, b and s were determined using multiple linear correlation analysis. It is shown, that the chains of the polymer have a significant influence on the solvatochromic behavior of 1-P. The structure of the carbonitrile 1-Si bound to polymer-modified silica particles was studied by means of X-ray photoelectron spectroscopy (XPS and Brunauer–Emmett–Teller (BET measurements. Fluorescent silica particles were obtained as shown by fluorescence spectroscopy with a diffuse reflectance technique.

  1. Polymer and Water Dynamics in Poly(vinyl alcohol/Poly(methacrylate Networks. A Molecular Dynamics Simulation and Incoherent Neutron Scattering Investigation

    Directory of Open Access Journals (Sweden)

    Ester Chiessi

    2011-10-01

    Full Text Available Chemically cross-linked polymer networks of poly(vinyl alcohol/poly(methacrylate form monolitic hydrogels and microgels suitable for biomedical applications, such as in situ tissue replacement and drug delivery. In this work, molecular dynamics (MD simulation and incoherent neutron scattering methods are used to study the local polymer dynamics and the polymer induced modification of water properties in poly(vinyl alcohol/poly(methacrylate hydrogels. This information is particularly relevant when the diffusion of metabolites and drugs is a requirement for the polymer microgel functionality. MD simulations of an atomic detailed model of the junction domain at the experimental hydration degree were carried out at 283, 293 and 313 K. The polymer-water interaction, the polymer connectivity and the water dynamics were investigated as a function of temperature. Simulation results are compared with findings of elastic and quasi-elastic incoherent neutron scattering measurements, experimental approaches which sample the same space-time window of MD simulations. This combined analysis shows a supercooled water component and an increase of hydrophilicity and mobility with temperature of these amphiphilic polymer networks.

  2. Fluorescence and picosecond induced absorption from the lowest singlet excited states of quercetin in solutions and polymer films

    Science.gov (United States)

    Bondarev, S. L.; Tikhomirov, S. A.; Buganov, O. V.; Knyukshto, V. N.; Raichenok, T. F.

    2017-03-01

    The spectroscopic and photophysical properties of the biologically important plant antioxidant quercetin in organic solvents, polymer films of polyvinyl alcohol, and a buffer solution at pH 7.0 are studied by stationary luminescence and femtosecond laser spectroscopy at room temperature and 77 K. The large magnitude of the dipole moment of the quercetin molecule in the excited Franck-Condon state μ e FC = 52.8 C m indicates the dipolar nature of quercetin in this excited state. The transient induced absorption spectra S 1→ S n in all solvents are characterized by a short-wave band at λ abs max = 460 nm with exponential decay times in the range of 10.0-20.0 ps. In the entire spectral range at times of >100 ps, no residual induced absorption was observed that could be attributed to the triplet-triplet transitions T 1 → T k in quercetin. In polar solvents, two-band fluorescence was also recorded at room temperature, which is due to the luminescence of the initial enol form of quercetin ( 415 nm) and its keto form with a transferred proton (550 nm). The short-wave band is absent in nonpolar 2-methyltetrahydrofuran (2-MTHF). The spectra of fluorescence and fluorescence excitation exhibit a low dependence on the wavelength of excitation and detection, which may be related to the solvation and conformational changes in the quercetin molecule. Decreasing the temperature of a glassy-like freezing quercetin solution in ethanol and 2-MTHF to 77 K leads to a strong increase in the intensity (by a factor of 100) of both bands. The energy circuits for the proton transfer process are proposed depending on the polarity of the medium. The main channel for the exchange of electronic excitation energy in the quercetin molecule at room temperature is the internal conversion S 1 ⇝ S 0, induced by the state with a proton transfer.

  3. Ultrasonic-assisted preparation of graphene oxide carboxylic acid polyvinyl alcohol polymer film and studies of thermal stability and surface resistivity.

    Science.gov (United States)

    Li, Yongshen; Li, Jihui; Li, Yuehai; Li, Yali; Song, Yunan; Niu, Shuai; Li, Ning

    2018-01-01

    In this paper, flake graphite, nitric acid and acetic anhydride are used to prepare graphene oxide carboxylic acid (GO-COOH) via an ultrasonic-assisted method, and GO-COOH and polyvinyl alcohol polymer (PVA) are used to synthesize graphene oxide carboxylic acid polyvinyl alcohol polymer (GO-COOPVA) via the ultrasonic-assisted method, and GO-COOPVA is used to manufacture graphene oxide carboxylic acid polyvinyl alcohol polymer film (GO-COOPVA film) via a solidification method, and the structure and morphology of GO-COOH, GO-COOPVA and GO-COOPVA film are characterized, and the thermal stability and surface resistivity are measured in the case of the different amount of GO-COOH. Based on the characterization and measurement, it has been successively confirmed and attested that carboxyl groups implant on 2D lattice of GO to form GO-COOH, and GO-COOH and PVA have the esterification reaction to produce GO-COOPVA, and GO-COOPVA consists of 2D lattice of GO-COOH and the chain of PVA connected in the form of carboxylic ester, and GO-COOPVA film is composed of GO-COOPVA, and the thermal stability of GO-COOPVA film obviously improves in comparison with PVA film, and the surface resistivity of GO-COOPVA film clearly decreases. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Improvement of Chromium(VI) Extraction from Acidic Solutions Using a Poly(vinyl chloride)-based Polymer Inclusion Membrane with Aliquat 336 as the Carrier.

    Science.gov (United States)

    Kagaya, Shigehiro; Maeno, Tomonori; Ito, Kazuma; Gemmei-Ide, Makoto; Cattrall, Robert W; Kolev, Spas D

    2017-01-01

    An important reason for the inefficient extraction of Cr(VI) from its acidic solutions into polymer inclusion membranes (PIMs), consisting of poly(vinyl chloride) as the base-polymer and Aliquat 336 as the carrier, was found to be associated with the leaching of Aliquat 336 from the PIMs into the solutions, where it subsequently reduced the anionic Cr(VI) species to cationic Cr(III) species. The PIM extraction efficiency for Cr(VI) was significantly improved by the addition of NaNO3 to the solutions, which suppressed the leaching of Aliquat 336 and the reduction of Cr(VI) to Cr(III).

  5. Poly(vinyl alcohol) as a water protecting agent for silver nanoparticles: the role of polymer size and structure.

    Science.gov (United States)

    Kyrychenko, Alexander; Pasko, Dmitry A; Kalugin, Oleg N

    2017-03-29

    Chemical modification of silver nanoparticles (AgNPs) with a stabilizing agent, such as poly(vinyl alcohol) (PVA), plays an important role in shape-controlled seeded-growth and colloidal stability. However, theoretical aspects of the stabilizing mechanism of PVA are still poorly understood. To gain a better understanding of the role of PVA in water protecting effects for silver nanoparticles, we developed an atomistic model of a AgNP grafted with single-chain PVA of various lengths. Our model, designed for classical molecular dynamics (MD) simulations, approximates the AgNP as a quasi-spherical silver nanocrystal with 3.9 nm diameter and uses a united-atom representation for PVA with its polymer chain length varying from 220 up to 1540 repeating units. We found that PVA adsorbs onto the AgNP surface through multiple non-covalent interactions, among which non-covalent bonding of the hydroxyl groups plays a key role. The analysis of adsorption isotherms by using the Hill, Scatchard, and McGhee & von Hippel models exhibits evidence for positive binding cooperativity with the cooperativity parameter varying from 1.55 to 2.12. Our results indicate that the size of the PVA polymer rather than its structure plays a crucial role in providing water protecting effects for the AgNP core, varying from 40% up to 91%. The water-protecting efficiency was well approximated by the Langmuir-Freundlich equation, allowing us to predict that the saturated coverage of the nanoparticle of a given diameter of 3.9 nm should occur when the PVA molecular weight approaches 115 kDa, which corresponds to the number of vinyl alcohol monomers being equal to 3100 units.

  6. A reference electrode based on polyvinyl butyral (PVB) polymer for decentralized chemical measurements

    Energy Technology Data Exchange (ETDEWEB)

    Guinovart, Tomàs [Departament de Química Orgànica i Química Analítica, Universitat Rovira i Virgili, Carrer Marcellí Domingo s/n 43007 Tarragona (Spain); Crespo, Gastón A. [Department of Inorganic and Analytical Chemistry, University of Geneva, Quai Ernest-Ansermet 30, CH-1211 Geneva (Switzerland); Rius, F. Xavier [Departament de Química Orgànica i Química Analítica, Universitat Rovira i Virgili, Carrer Marcellí Domingo s/n 43007 Tarragona (Spain); Andrade, Francisco J., E-mail: franciscojavier.andrade@urv.cat [Departament de Química Orgànica i Química Analítica, Universitat Rovira i Virgili, Carrer Marcellí Domingo s/n 43007 Tarragona (Spain)

    2014-04-01

    Highlights: • A disposable solid-contact reference electrode for potentiometry is presented. • The device shows unsensitivity to most ions, redox potential and light. • Low-cost and good stability, ideal to build disposable potentiometric sensors. • Nanopores formed in the membrane control the flux of ions with the solution. Abstract: A new solid-state reference electrode using a polymeric membrane of polyvinyl butyral (PVB), Ag/AgCl and NaCl to be used in decentralized chemical measurements is presented. The electrode is made by drop-casting the membrane cocktail onto a glassy carbon (GC) substrate. A stable potential (less than 1 mV dec⁻¹ over a wide range of concentrations for the several chemical species tested is obtained. No significant influence to changes in redox potential, light and pH are observed. The response of this novel electrode shows good correlation when compared with a conventional double-junction reference electrode. Also good long-term stability (90 ± 33 μV/h) and a lifetime of approximately 4 months are obtained. Aspects related to the working mechanisms are discussed. Atomic Force Microscopy (AFM) studies reveal the presence of nanopores and channels on the surface, and electrochemical impedance spectroscopy (EIS) of optimized electrodes show low bulk resistances, usually in the kΩ range, suggesting that a nanoporous polymeric structure is formed in the interface with the solution. Future applications of this electrode as a disposable device for decentralized measurements are discussed. Examples of the utilization on wearable substrates (tattoos, fabrics, etc) are provided.

  7. Radiation-crosslinking of shape memory polymers based on poly(vinyl alcohol) in the presence of carbon nanotubes

    Science.gov (United States)

    Basfar, A. A.; Lotfy, S.

    2015-01-01

    Shape memory polymers based on poly(vinyl alcohol) (SM-PVA) in the presence of 2-carboxyethyl acrylate oligomers (CEA) and multi-wall carbon nanotubes (MWCNTs) crosslinked by ionizing radiation were investigated. Chemical-crosslinking of PVA by glutaraldehyde in the presence of CEA and MWCNTs was also studied. The swelling and gel fraction of the radiation-crosslinked SM-PVA and chemically crosslinked systems were evaluated. Analysis of the swelling and gel fraction revealed a significant reduction in swelling and an increase in the gel fraction of the material that was chemically crosslinked with glutaraldehyde. The radiation-crosslinked SM-PVA demonstrated 100% gelation at an irradiation dose of 50 kGy. In addition, radiation-crosslinked SM-PVA exhibited good temperature responsive shape-memory behavior. A scanning electron microscopy (SEM) analysis was performed. The thermal properties of radiation-crosslinked SM-PVA were investigated by a thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). The ability of the material to return or store energy (E‧), to its ability to lose energy (E″), and the ratio of these effects (Tanδ), which is called damping were examined via DMA. The temperature of Tanδ in the radiation-crosslinked SM-PVA decreased significantly by 6 and 13 °C as a result of the addition of MWCNTs. In addition, the temperature of Tanδ for SM-PVA increased as the irradiation dose increased. These radiation-crosslinked SM-PVA materials show promising shape-memory behavior based on the range of temperatures at which Tanδ appears.

  8. Hydrogenation induced deviation of temperature and concentration dependences of polymer-solvent interactions in poly(vinyl chloride) and a new eco-friendly plasticizer

    Science.gov (United States)

    Liu, Yang; Zhang, Rongchun; Wang, Xiaoliang; Sun, Pingchuan; Chen, Wei; Shen, Jianyi; Xue, Gi

    2015-06-01

    As a substitute for di-2-ethylhexyl phthalate (DOP), a new eco-friendly plasticizer, di(2-ethylhexyl) cyclohexane-1,2-dicarboxylate (DEHHP), was systematically studied in this work, mainly focusing on its interaction with poly(vinyl chloride) (PVC). The temperature and concentration dependences of polymer-solvent interactions in PVC/DEHHP were systematically investigated by rheology, low-field NMR and molecular dynamics simulations, and the results were quite different from those in PVC/DOP. With temperature increasing or PVC concentration decreasing, rheology experiments revealed that polymer-solvent interactions in PVC/DEHHP were weaker than that in PVC/DOP. Low-field 1H NMR results showed that the number of polymer-solvent complexes decreased as temperature increased. A faster decreasing rate of this number made the polymer-solvent interactions weaker in PVC/DEHHP than in PVC/DOP. Molecular dynamics simulations were further performed to study the role of polymer-solvent hydrogen bonding interactions in the systems. The radial distribution function showed that heating and dilution both resulted in faster molecular motions, and disassociation of the hydrogen bonds in the simplex hydrogen bonding system. Therefore, heating and dilution had an equivalent effect on the polymer-solvent interactions.

  9. Charge-discharge characteristics of LiCoO 2/mesocarbon microbeads battery with poly(vinyl chloride)-based composite polymer electrolyte

    Science.gov (United States)

    Subban, R. H. Y.; Arof, A. K.

    Polyvinyl chloride (PVC)-based composite polymer electrolyte films consisting of PVC-LiCF 3SO 3-SiO 2 are prepared by the solution-casting method. The electrical properties of the electrolyte are investigated for ionic conductivity and its dependence on temperature. The electrolyte with the highest ionic conductivity is used to fabricate a LiCoO 2/PVC-LiCF 3SO 3-SiO 2/mesocarbon microbeads (MCMB) battery. The charge-discharge characteristics and performance of the battery at room temperature are evaluated to ascertain the effective viability, of these solid electrolytes in lithium-polymer batteries. Battery performances is also investigated at 313, 323 and 333 K.

  10. Study of poly(vinyl alcohol)/titanium oxide composite polymer membranes and their application on alkaline direct alcohol fuel cell

    Science.gov (United States)

    Yang, Chun-Chen; Chiu, Shwu-Jer; Lee, Kuo-Tong; Chien, Wen-Chen; Lin, Che-Tseng; Huang, Ching-An

    The novel poly(vinyl alcohol)/titanium oxide (PVA/TiO 2) composite polymer membrane was prepared using a solution casting method. The characteristic properties of the PVA/TiO 2 composite polymer membrane were investigated by thermal gravimetric analysis (TGA), a scanning electron microscopy (SEM), a micro-Raman spectroscopy, a methanol permeability measurement and the AC impedance method. An alkaline direct alcohol (methanol, ethanol and isopropanol) fuel cell (DAFC), consisting of an air cathode based on MnO 2/C inks, an anode based on PtRu (1:1) black and a PVA/TiO 2 composite polymer membrane, was assembled and examined for the first time. The results indicate that the alkaline DAFC comprised of a cheap, non-perfluorinated PVA/TiO 2 composite polymer membrane shows an improved electrochemical performances. The maximum power densities of alkaline DAFCs with 4 M KOH + 2 M CH 3OH, 2 M C 2H 5OH and 2 M isopropanol (IPA) solutions at room temperature and ambient air are 9.25, 8.00, and 5.45 mW cm -2, respectively. As a result, methanol shows the highest maximum power density among three alcohols. The PVA/TiO 2 composite polymer membrane with the permeability values in the order of 10 -7 to 10 -8 cm 2 s -1 is a potential candidate for use on alkaline DAFCs.

  11. Investigating the effects of polymer molecular weight and non-solvent content on the phase separation, surface morphology and hydrophobicity of polyvinyl chloride films

    Science.gov (United States)

    Khoryani, Zahra; Seyfi, Javad; Nekoei, Mehdi

    2018-01-01

    The main aim of this research is to study the effects of polymer molecular weight as well as non-solvent concentration on the phase separation, surface morphology and wettability of polyvinyl chloride (PVC) films. Gel permeation chromatography (GPC) results showed that the Mn of the used PVC grades is 6 × 104, 8.7 × 104 and 1.26 × 105 g/mol. It was found that a proper combination of polymer molecular weight and non-solvent content could result in superhydrophobic and self-cleaning behaviors. Scanning electron microscopy (SEM) results demonstrated that addition of ethanol causes the polymer chains to be severely aggregated at the films' surface forming strand-like structures decorated by nano-scale polymer spheres. The polymer molecular weight was found to affect the degree of porosity which is highly influential on the hydrophobicity of the films. The mechanism of phase separation process was also discussed and it was found that the instantaneous demixing is the dominant mechanism once higher contents of non-solvent were used. However, a delayed demixing mechanism was detected when the lower molecular weight PVC has been used which resulted in a pore-less and dense skin layer. Differential scanning calorimetry was also utilized to study the crystallization and glass transition behavior of samples.

  12. Polymer-filler interactions in poly(vinyl chloride) filled with glass beads : effect of grafted poly(methyl methacrylate)

    NARCIS (Netherlands)

    Boven, Gert; Folkersma, Rudy; Challa, Ger; Schouten, Arend Jan; Bosma, Martin

    1992-01-01

    Adhesion between filler and matrix has been studied using a model system composed of glass bead filled poly(vinyl chloride) (PVC). Stress-strain and volume-strain tests and scanning electron microscopy revealed that adhesion is improved by grafting poly(methyl methacrylate) (PMMA), which is known to

  13. Chemical treatment of membranes of a polymer blend: mechanism of the reaction of hypochlorite with poly(vinyl pyrrolidone)

    NARCIS (Netherlands)

    Wienk, I.M.; Wienk, I.M.; Meuleman, E.E.B.; Meuleman, E.E.B.; Borneman, Zandrie; van den Boomgaard, Anthonie; Smolders, C.A.; Smolders, C.A.

    1995-01-01

    Sodium hypochlorite solutions are used to treat membranes prepared from a polymeric blend containing poly(vinyl pyrrolidone) (PVP) to increase their water permeability. Sodium hypochlorite affects the membrane material in such a way that PVP is selectively removed from the membrane matrix. The

  14. Excited-State Interaction of Semiconducting Single-Walled Carbon Nanotubes with Their Wrapping Polymers.

    Science.gov (United States)

    Kahmann, Simon; Salazar Rios, Jorge M; Zink, Matthias; Allard, Sybille; Scherf, Ullrich; Dos Santos, Maria C; Brabec, Christoph J; Loi, Maria A

    2017-11-16

    We employ photoluminescence and pump-probe spectroscopy on films of semiconducting single-walled carbon nanotubes (CNTs) of different chirality wrapped with either a wide band gap polyfluorene derivative (PF12) or a polythiophene with narrower gap (P3DDT) to elucidate the excited states' interplay between the two materials. Excitation above the polymer band gap gives way to an ultrafast electron transfer from both polymers toward the CNTs. By monitoring the hole polaron on the polymer via its mid infrared signature, we show that also illumination below the polymer band gap leads to the formation of this fingerprint and infer that holes are also transferred toward the polymer. As this contradicts the standard way of discussing the involved energy levels, we propose that polymer-wrapped CNTs should be considered as a single hybrid system, exhibiting states shared between the two components. This proposition is validated through quantum chemical calculations that show hybridization of the first excited states, especially for the thiophene-CNT sample.

  15. Modifying Poly(Vinyl Alcohol) (PVA) from Insulator to Small-Bandgap Polymer: A Novel Approach for Organic Solar Cells and Optoelectronic Devices

    Science.gov (United States)

    Aziz, Shujahadeen B.

    2016-01-01

    An innovative method has been used to reduce the bandgap of poly(vinyl alcohol) (PVA) polymer by addition of a nontoxic, inexpensive, and environmentally friendly material. The resulting materials are small-bandgap polymers, hence opening new frontiers in green chemistry. The doped PVA films showed a wide range of light absorption of the solar spectrum from 200 nm to above 800 nm. Nonsharp absorption behavior versus wavelength was observed for the samples. The refractive index exhibited a wide range of dispersion. Shift of the absorption edge from 6.2 eV to 1.5 eV was observed. The energy bandgap of PVA was diminished to 1.85 eV upon addition of black tea extract solution, lying in the range of small-bandgap polymers. Increase of the optical dielectric constant was observed with increasing tea solution addition. The results indicate that small-bandgap PVA with good film-forming ability could be useful in terms of cost-performance tradeoff, solving problems of short lifetime, cost, and flexibility associated with conjugated polymers. The decrease of the Urbach energy upon addition of black tea extract solution indicates modification of PVA from a disordered to ordered material. X-ray diffraction results confirm an increase of the crystalline fraction in the doped samples.

  16. Electrochemical performance of an air-breathing direct methanol fuel cell using poly(vinyl alcohol)/hydroxyapatite composite polymer membrane

    Science.gov (United States)

    Yang, Chun-Chen; Chiu, Shwu-Jer; Lin, Che-Tseng

    A novel composite polymer membrane based on poly(vinyl alcohol)/hydroxyapatite (PVA/HAP) was successfully prepared by a solution casting method. The characteristic properties of the PVA/HAP composite polymer membranes were examined by thermal gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), micro-Raman spectroscopy and AC impedance method. An air-breathing DMFC, comprised of an air cathode electrode with MnO 2/BP2000 carbon inks on Ni-foam, an anode electrode with PtRu black on Ti-mesh, and the PVA/HAP composite polymer membrane, was assembled and studied. It was found that this alkaline DMFC showed an improved electrochemical performance at ambient temperature and pressure; the maximum peak power density of an air-breathing DMFC in 8 M KOH + 2 M CH 3OH solution is about 11.48 mW cm -2. From the application point of view, these composite polymer membranes show a high potential for the DMFC applications.

  17. Response surface method (RSM) for optimization of ionic conductivity of membranes polymer electrolyte poly (vinylidene fluoride) (PVDF) with polyvinyl pyrrolidone (PVP) as pore forming agent

    Science.gov (United States)

    Dyartanti, E. R.; Susanto, H.; Widiasa, I. N.; Purwanto, A.

    2017-06-01

    The Membranes Polymer Gel Electrolyte (MPGEs) based poly (vinylidene fluoride) (PVDF) was prepared by a phase inversion method using polyvinyl pyrrolidone (PVP) as a pore-forming agent and N, N-dimethyl acetamide (DMAc) as a solvent and water as non solvet. The membranes were then soaked in 1 M lithium hexafluorophosphate (LiPF6) in ethylene carbonate (EC) / dimethyl carbonate (DMC) / Diethyl carbonate (DEC) (4:2:4 %vol) solution in order to prepare polymer electrolyte membranes. The MPEGs PVDF/PVP/Nanoclay was applied using central composite design (CCD) experimental design to obtain a quantitative relationship between selected membranes prepared parameters namely (PVDF, PVP as pore forming agent and nanoclay filler concentration) and Ionic conductivity MPEGs. The model was used to find the optimum ionic conductivity from polymer electrolyte membranes. The polymer electrolyte membranes show good ionic conductivity on the order of 6.3 - 8.7 x 10-3 S cm-1 at the ambient temperatures. The ionic conductivity tended to increase with PVP and nanoclay concentration and decrease with PVDF composition. The model predicted the maximum ionic conductivity of 8.47 x 10-3 S cm-1 when the PVDF, PVP and nanoclay concentration were set at 8.01 %, 8.04 % and 10.12%, respectively. The first section in your paper.

  18. Synthesis and character investigation of new collagen Hydrolysate/polyvinyl alcohol/hydroxyapatite Polymer-Nano-Porous Membranes: I. Experimental design optimization in thermal and structural properties.

    Science.gov (United States)

    Imanieh, Hossein; Aghahosseini, Hamideh

    2013-12-01

    Development of bioorganic-inorganic composites has drawn eyes to extensive attention in biomedical fields and tissue engineering. So many attempts to prepare hydroxyapatite (HA), in conjunction with various binders including polyvinyl alcohol (PVA), and collagen has performed for late 20 years. We applied a method based on the phase separation for making of polymer porous membranes. This procedure is induced through the addition of a small quantity of water (polymer-rich phase) to a solution with HA precursors (polymer-poor phase). Thermal and structural composite properties of collagen Hydrolysate (CH)-PVA/HA Polymer-Nano-Porous Membranes were analyzed by Design of experiment that was undertaken using D-optimal approach, to select the optimal combination of nano composites precursor. The resulted composite characters were investigated by Fourier transform infrared, scanning electron microscopy (SEM) and thermal gravimetric analysis. Based on the SEM images, this new method could be clearly concluded to porous CH-PVA/HA hybrid materials. Finally the hemocompatibility of nanocomposite membranes were evaluated by the hemolysis study.

  19. Sensitized green emission of terbium with dibenzoylmethane and 1, 10 phenanthroline in polyvinyl alcohol and polyvinyl pyrrolidone blends

    Science.gov (United States)

    Kumar, Brijesh; Kaur, Gagandeep; Rai, S. B.

    2017-12-01

    Tb doped polyvinyl alcohol: polyvinyl pyrrolidone blends with dibenzoylmethane (DBM) and 1, 10 Phenanthroline (Phen) have been prepared by solution cast technique. Bond formation amongst the ligands and Tb3 + ions in the doped polymer has been confirmed employing Fourier Transform Infrared (FTIR) techniques. Optical properties of the Tb3 + ions have been investigated using UV-Vis absorption, excitation and fluorescence studies excited by different radiations. Addition of dimethylbenzoate and 1, 10 Phenanthroline to the polymer blend increases the luminescence from Tb3 + ions along with energy transfer from the polymer blend itself. Luminescence decay curve analysis affirms the non-radiative energy transfer from DBM and Phen to Tb3 + ions, which is identified as the reason behind this enhancement. The fluorescence decay time of PVA-PVP host decreases from 6.02 ns to 2.31 ns showing an evidence of energy transfer from the host blend to the complexed Tb ions. Similarly the lifetime of DBM and Phen and both in the blend reduces in the complexed system showing the feasibility of energy transfer from these excited DBM and Phen to Tb3 + and is proposed as the cause of the above observations. These entire phenomena have been explained by the energy level diagram.

  20. Surface-enhanced fluorescence in metal nanoparticle-doped polymer nanofibers via waveguiding excitation

    Science.gov (United States)

    Yu, Jiaxin; Liao, Feng; Liu, Fang; Gu, Fuxing; Zeng, Heping

    2017-04-01

    We report a waveguiding excitation-based approach for surface-enhanced fluorescence. As high as 17-fold enhanced fluorescence intensity of Rhodamine 6G molecules is realized by gold nanoparticles embedded in polymer nanofibers. The enhancement results not only from the spatial confinement of light by the nanofibers but also from the wavelength match among the excitation laser, the localized surface plasmon resonance of nanoparticles, and the absorption band of dyes. On the basis of the enhancement and high-efficient waveguiding regime, the required excitation power for detectable fluorescence is decreased to the 20 nW level, which is about 50 times lower than that by free-space excitation. These fluorophore/nanoparticle-doped nanofibers may find applications in compact and energy-efficient optical devices of chemical analysis and biosensing.

  1. Dielectric relaxation, structural and thermal studies of 95 MeV O6+ ion irradiated conducting polymer polyaniline-polyvinyl alcohol

    Science.gov (United States)

    Himanshu, A. K.; Ray, Rajyavardhan; El-Sayed, S.; Hassen, A.; Bandyopadhayay, S. K.; Sinha, T. P.

    2014-01-01

    Polyaniline (PANI) film prepared from using water-soluble support polymer polyvinyl alcohol (PVA) has been irradiated with 95 MeV oxygen (O6+) ions at the fluences from 1011 to 1012 ions/cm2. The thermal, dielectric, structural and microstructural properties of the samples are investigated by differential scanning calorimeter and thermogravimetric analysis, LCR meter, X-ray diffraction and scanning electron microscope. The structural studies reveal that amorphization on irradiation which may be due to the scission of polymer bonds as there is a signature of columnar tracts and the appearance of voids in the sample increases with increasing O6+ ions irradiation-dose. Frequency-dependent spectra of the imaginary electric modulus suggest that long-range conduction in pristine sample changes to short-range, i.e. localized conduction in 95 MeV O6+ ion-irradiation PANI-PVA. The behaviour of the ac conductivity reveals that the conduction mechanism in both pristine and irradiated sample is correlated to the barrier hopping model.

  2. Light-induced switching of the wettability of novel asymmetrical poly(vinyl alcohol)-co-ethylene membranes blended with azobenzene polymers.

    Science.gov (United States)

    Tylkowski, Bartosz; Peris, Sergio; Giamberini, Marta; Garcia-Valls, Ricard; Reina, José A; Ronda, Joan C

    2010-09-21

    Novel composite asymmetrical membranes based on poly(vinyl alcohol)-co-ethylene (EVAL) as the host material and new polyethers that contain azobenzene moieties in the side chain were prepared by dry-cast phase inversion after dissolving the azo polymers in tetrahydrofuran and EVAL in dimethylsulfoxide and subsequently mixing the resulting solutions. By taking advantage of the proper temperature variation in the oven used for solvent evaporation, asymmetrical membranes that exhibited a dense, crystalline layer on the bottom and a porous, mainly amorphous layer on the top were obtained. Remarkable changes in the surface morphology and the contact angle with water were observed on the top surfaces of the composite membranes. This was ascribed not only to the enhanced concentration of azo polymer on the top surface but mostly to a conformational change in EVAL induced by the photoisomerization of the guest azo groups, as shown by HRMAS (1)H NMR. The morphological and structural changes in EVAL could be reversed on exposing the membrane to visible light for 24 h.

  3. Viscometric Studies of Poly(ethylene glycol), Poly(vinyl alcohol) and Poly(vinyl chloride) and Their Mixtures in Water and Chlorobenzene

    OpenAIRE

    Ur Rashid, Harun

    1989-01-01

    Absolute viscosities of semi-dilute solutions of polytethylene. glycol) and poly(vinyl alcohol) and their mixtures in water and of poly(ethylene glycol) and poly(vinyl chloride) and the ir mixtures in chlorobenzene have been measured at 30 C C. The viscosities of poly(vinyl alcohol) and poly(vinyl chloride) increase sharply with concentration. The plots of viscosity of polymer mixtures against composition deviate from linearity. The effect of total polymer content on the ...

  4. Boronate-containing polymers form affinity complexes with mucin and enable tight and reversible occlusion of mucosal lumen by poly(vinyl alcohol) gel.

    Science.gov (United States)

    Ivanov, Alexander E; Nilsson, Lars; Galaev, Igor Yu; Mattiasson, Bo

    2008-06-24

    Copolymers of N-acryloyl-m-aminophenylboronic acid (NAAPBA) with N,N-dimethylacrylamide (DMAA) formed insoluble interpolymer complexes with mucin from porcine stomach at pH 9.0. The complex formation based on boronate-sugar interactions took place between the similarly charged macromolecules and resulted in coacervate particles formation, which depended both on pH and ionic strength of the solution. The coacervation rate displayed a maximum at the intermediate DMAA-NAAPBA copolymer: mucin weight ratio, that is a pattern typical of interpolymer complex formation. The effective hydrodynamic particle diameter of the coacervates monotonously grew from 155+/-20 nm up to 730+/-120 nm in 2 days in 0.1M sodium bicarbonate buffer solution, pH 9.0. Electrophoretic mobility of the resultant nanoparticles was intermediate between those of individual polymers, whereas the particles zeta-potential was -7.5+/-0.4 mV in the above buffer solution. Pre-treatment of the inner mucosal epithelium of excised male pig urethras with 5% (w/v) solutions of acrylamide-NAAPBA or DMAA-NAAPBA copolymers at pH 8.8 allowed for tight occlusion of the lumen by poly(vinyl alcohol)-borax gel injected via a two-way catheter. Leakage of 0.15M NaCl solution through the thus occluded organs could be prevented, while the leakage through the organs occluded by the gel without the pre-treatment was unavoidable. The gel plug could be quickly dissolved on demand after injection of 5% (w/v) aqueous fructose solution into the lumen. The described technique may be useful for temporal occlusion of mucosal lumens in living organisms. In contrast to the conventional mucoadhesive polymers like polyacrylic acid or chitosan, the boronate-containing copolymers display their mucoadhesivity at weakly alkaline pH of 8-9 and physiological ionic strength.

  5. Influence of matrix rigidity on the internal twisting of electronically excited thioflavin T in polymer nanostructures

    Science.gov (United States)

    Lee, Youmin; Kim, Yu Lim; Kim, Myung Hwa; Lee, Minyung

    2013-11-01

    Thioflavin T (ThT) exhibits an enormous increase in fluorescence intensity (or lifetime) upon binding to β-sheet rich protein aggregates. In this letter, we measured the fluorescence lifetimes of ThT in poly (ethylene oxide) (PEO) and poly (acrylic acid) (PAA) polymer films and nanofibers and observed that the excited-state motion of ThT is slowed down as the mechanical rigidity of medium increases. Using ThT as a rigidity sensor, we first demonstrate that the fluorescence lifetime imaging microscopy (FLIM) can easily distinguish the PEO and PAA nanofiber structures, which were not discernable by electron microscopy.

  6. Optimization of Environmentally Benign Polymers Based on Thymine and Polyvinyl Sulfonate Using Plackett-Burman Design and Surface Response

    Directory of Open Access Journals (Sweden)

    Julieta Ledesma

    2013-01-01

    Full Text Available Traditional approaches to the development of integrated circuits involve the use and/or manufacture of toxic materials that have a potential environmental impact. An extensive research has been done to design environmentally benign synthetic polymers containing nucleic acid bases, which can be used to enhance the photoresistor technologies. Water soluble, environmentally benign photopolymers of 1-(4-vinylbenzyl thymine (VBT and vinylphenyl sufonate (VPS undergo a photodimerization reaction when exposed to low levels of ultraviolet irradiation leading to an immobilization of the copolymer on a variety of substrates. Plackett-Burman design (PBD and central composite design (CCD were applied to identify the significant factors influencing the polymer crosslinking and dye adsorption processes, which are relevant in the fabrication of copolymer films for potential photoresist use. The PBD results assigned a maximum absorption signal of 0.67, while optimal conditions obtained in this experiment following the CCD method predictions provided a response of 0.83 ± 0.03, being a solid foundation for further use of this methodology in the production of potential photoresistors. The pH effect was relevant for low concentrations but not significant for higher concentrations. To the best of our knowledge, this was the first report applying statistical experimental designs to optimize the crosslinking of thymine-based polymers.

  7. Second harmonic generation in NLO polymers excited by Surface Plasmon enhanced electric field induced by femtosecond optical pulses

    Directory of Open Access Journals (Sweden)

    Kawata Y.

    2013-03-01

    Full Text Available We will report second harmonic generation (SHG in nonlinear optical (NLO polymers excited by surface plasmon enhanced optical fields. The surface plasmon (SP polariton was excited in an attenuated total reflection geometry having the Kretchmann configuration. The NLO polymers, consisting of Disperse Red1 as guest chromophores and poly (methyl methacrylate as host materials, were coated upon the Ag layers. Our experimental results indicated that the SHG signal intensity from the polymer coated Ag films was more than 10 times higher than that from the non-coated Ag films. The SHG autocorrelation traces excited by SP-enhanced fields were also studied and the correlation time was shorter than 150 fs, the temporal resolutions of the present spectrometer.

  8. A novel organic/inorganic polymer membrane based on poly(vinyl alcohol)/poly(2-acrylamido-2-methyl-1-propanesulfonic acid/3-glycidyloxypropyl trimethoxysilane polymer electrolyte membrane for direct methanol fuel cells

    Science.gov (United States)

    Yang, Chun-Chen; Lue, Shingjiang Jessie; Shih, Jeng-Ywan

    2011-05-01

    Poly(vinyl alcohol)/poly(2-acrylamido-2-methyl-1-propanesulfonic acid (PAMPS)/3-glycidyloxypropyl)trimethoxysilane (PVA/PAMPS/GPTMS) organic/inorganic proton-conducting polymer membranes are prepared by a solution casting method. PAMPS is a polymeric acid commonly used as a primary proton donor, while 3-(glycidyloxypropyl)trimethoxysilane (GPTMS) is an inorganic precursor forming a semi-interpenetrating network (SIPN). Varying amounts of sulfosuccinic acid (SSA) are used as the cross-linker and secondary proton source. The characteristic properties of PVA/PAMPS/GPTMS composite membranes are investigated by thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), micro-Raman spectroscopy and the AC impedance method. Direct methanol fuel cells (DMFCs) made of PVA/PAMPS/GPTMS composite membranes are assembled and examined. Experimental results indicate that DMFCs employing an inexpensive, non-perfluorinated, organic/inorganic SIPN membrane achieve good electrochemical performance. The highest peak power density of a DMFC using PVA/PAMPS/GPTMS composite membrane with 2 M CH3OH solution fuel at ambient temperature is 23.63 mW cm-2. The proposed organic/inorganic proton-conducting membrane based on PVA/PAMPS/GPTMS appears to be a viable candidate for future DMFC applications.

  9. Spectromicroscopy of Polymers: Comparison of Radiation Damage with Electron and Photon Core Excitation Spectroscopy Techniques

    Science.gov (United States)

    Ade, H.; Smith, A. P.; Rightor, E. G.; Hitchcock, A. P.; Urquhart, S.; Leapman, R.

    1997-03-01

    Core excitation microspectroscopy has become a powerful tool for the characterization of polymeric materials due to its sensitivity to chemical functionality. However, the excitations utilized in electron energy loss spectroscopy performed in a scanning transmission electron microscope (TEM-EELS) and near edge x-ray absorption fine structure (NEXAFS) spectroscopy can introduce radiation damage and chemically modify the sample. In order to understand the radiation damage associated with TEM-EELS and NEXAFS spectroscopy we have studied the radiation damage of the common polymer poly(ethylene terephthalate) (PET) as exhibited by changes in the acquired C K-edge excitation spectra. By fitting gaussian functions to the spectral intensity changes as a function of dose, we have determined the critical radiation dose of PET for both NEXAFS spectroscopy and TEM-EELS under typical operating conditions. This critical radiation dose for TEM-EELS is found to be 1.7 ± 0.2 x 10^8 grey (1.7 ± 0.2 x 10^4 Mrad) compared to a critical radiation dose for NEXAFS spectroscopy of 1.4 ± 0.7 x 10^9 grey (1.4 ± 0.7 x 10^5 Mrad). By considering the G factors of the two techniques and the critical radiation dose, a rule of thumb was derived that indicates that with typical present operating conditions, NEXAFS spectroscopy can analyze areas 500 times smaller than TEM-EELS given the same amount of radiation damage. Work supported by: NSF Young Investigator Award (DMR-9458060) and Dow Chemical

  10. Below-Gap Excitation of π-Conjugated Polymer-Fullerene Blends: Implications for Bulk Organic Heterojunction Solar Cells

    Science.gov (United States)

    Drori, T.; Sheng, C.-X.; Ndobe, A.; Singh, S.; Holt, J.; Vardeny, Z. V.

    2008-07-01

    We used a variety of optoelectronic techniques such as broadband fs transient and cw photomodulation spectroscopies, electroabsorption, and short-circuit photocurrent in bulk heterojunctions organic solar cells for studying the photophysics in π-conjugated polymer-fullerene blends with below-gap excitation. In contrast to the traditional view, we found that below-gap excitation, which is incapable of generating intrachain excitons, nevertheless efficiently generates polarons on the polymer chains and fullerene molecules. The polaron action spectrum extends deep inside the gap as a result of a charge-transfer complex state formed between the polymer chain and fullerene molecule. With appropriate design engineering the long-lived polarons might be harvested in solar cell devices.

  11. Geometrical relaxation of excitations in one-dimensional conjugated polymers; Giichijigen kyoeki kobunshi reiki jotai no shusa kozo kanwa

    Energy Technology Data Exchange (ETDEWEB)

    Yoshizawa, M. [Tohoku University, Sendai (Japan). Faculty of Engineering

    1995-12-15

    Large ultrafast optical nonlinearities in conjugated polymers have attracted much attention because of possible applications to nonlinear optical devices. One-dimensional systems such as conjugated polymers have localized excited states with geometrical relaxation. In this study, photoexcited states in polydiacetylene has been investigated by femtosecond Raman gain spectroscopy with 300-fs resolution. A new photoinduced Raman peak with lifetime of 1.5 ps has been observed at 1200cm{sup -1} for the first time. This peak indicates acetylene-like structure of the main chain relaxes to butatriene-like structure due to the formation of self-trapped exciting with the geometrical relaxation. The formation and decay kinetics of the Raman signals is consistent with the relaxation processes of exciting observed by femtosecond absorption spectroscopy. 8 refs., 5 figs.

  12. MECHANICAL PROPERTIES OF BLENDS OF PAMAM DENDRIMERS WITH POLY(VINYL CHLORIDE) AND POLY(VINYL ACETATE)

    Science.gov (United States)

    Hybrid blends of poly(amidoamine) PAMAM dendrimers with two linear high polymers, poly(vinyl chloride), PVC, and poly(vinyl acetate), PVAc, are reported. The interaction between the blend components was studied using dynamic mechanical analysis, xenon nuclear magnetic resonacne ...

  13. The surface structure and thermal properties of novel polymer composite films based on partially phosphorylated poly(vinyl alcohol) with aluminum phosphate.

    Science.gov (United States)

    Mohamed Saat, Asmalina; Johan, Mohd Rafie

    2014-01-01

    Partially phosphorylated polyvinyl alcohol (PPVA) with aluminum phosphate (ALPO4) composites was synthesized by solution casting technique to produce (PPVA)(100-y) - (ALPO4)(y) (y = 0, 1, and 2). The surface structure and thermal properties of the films were characterized using Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The results showed that the films have higher thermal stability with strong bonding between PPVA and ALPO4.

  14. The Surface Structure and Thermal Properties of Novel Polymer Composite Films Based on Partially Phosphorylated Poly(vinyl alcohol with Aluminum Phosphate

    Directory of Open Access Journals (Sweden)

    Asmalina Mohamed Saat

    2014-01-01

    Full Text Available Partially phosphorylated polyvinyl alcohol (PPVA with aluminum phosphate (ALPO4 composites was synthesized by solution casting technique to produce (PPVA100-y-(ALPO4y (y = 0, 1, and 2. The surface structure and thermal properties of the films were characterized using Fourier transform infrared (FTIR spectroscopy and thermogravimetric analysis (TGA. The results showed that the films have higher thermal stability with strong bonding between PPVA and ALPO4.

  15. Effects of Molecular Stresses on Energy Transfer Pathways in Opto- and Electro-Excited Conjugated Polymers for High-Efficiency Optoelectronic Devices

    Science.gov (United States)

    2014-10-20

    effects of stretching the conjugated polymer of MEH-PPV (Mw = 55kg/mole) on the photoluminescence behavior was further studied in the experiment of...in Opto- and Electro-Excitated Conjugated Polymers for High- Efficiency Optoelectronic Devices 5a. CONTRACT NUMBER FA2386-12-1-4064 5b. GRANT...The role of mechanical stresses in the optoelectronic behavior and exciton formation of conjugated polymers was explored in order to understand and to

  16. Adsorption of poly(vinyl formamide-co-vinyl amine) (PVFA-co-PVAm) polymers on zinc, zinc oxide, iron, and iron oxide surfaces.

    Science.gov (United States)

    Seifert, Susan; Simon, Frank; Baumann, Giesela; Hietschold, Michael; Seifert, Andreas; Spange, Stefan

    2011-12-06

    The adsorption of poly(vinyl formamide) (PVFA) and the statistic copolymers poly(vinyl formamide-co-vinyl amine) (PVFA-co-PVAm) onto zinc and iron metal particles as well as their oxides was investigated. The adsorbates were characterized by means of XPS, DRIFT spectroscopy, wet chemical analysis, and solvatochromic probes. Dicyano-bis-(1,10-phenanthroline)-iron(II) (1), 3-(4-amino-3-methylphenyl)-7-phenyl-benzo-[1,2-b:4,5-b']difuran-2,6-dione (2), and 4-tert-butyl-2-(dicyano-methylene)-5-[4-(diethylamino)-benzylidene]-Δ(3)-thiazoline (3) as solvatochromic probes were coadsorbed onto zinc oxide to measure various effects of surface polarity. The experimental findings showed that the adsorption mechanism of PVFA and PVFA-co-PVAm strongly depends on the degree of hydrolysis of PVFA and pH values and also on the kind of metal or metal oxide surfaces that were employed as adsorbents. The adsorption mechanism of PVFA/PVFA-co-PVAm onto zinc oxide and iron oxide surfaces is mainly affected by electrostatic interactions. Particularly in the region of pH 5, the adsorption of PVFA/PVFA-co-PVAm onto zinc and iron metal particles is additionally influenced by redox processes, dissolution, and complexation reactions. © 2011 American Chemical Society

  17. In situ generation of silver nanoparticles in poly(vinyl alcohol)/poly(acrylic acid) polymer membranes in the absence of reducing agent and their effect on pervaporation of a water/acetic acid mixture

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhard, Shvshankar; Kwon, Yong Sung; Moon, MyungJun; Shon, Min Young [Dept. of Industrial Chemistry, Pukyong National University, Busan (Korea, Republic of); Park, You In; Nam, Seung Eun [Center for membranes, Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of)

    2016-12-15

    The in situ generation of silver nanoparticles in a poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) polymer matrix in the absence of any additional reducing agent is reported and tends to the membrane fabrication using solution-casting. Its effect on the separation of a water/acetic acid mixture by pervaporation is described. The results of UV spectroscopy, scanning electron microscopy, and scanning electron microscopy/energy-dispersive X-ray spectroscopy analyses showed that the silver nanoparticles were successfully prepared and well dispersed in the polymer matrix. The increased hydrophilicity of the PVA/PAA membrane due to the presence of silver nanoparticles was confirmed by Fourier transform infrared spectroscopy, contact angle measurements, and membrane absorption studies. Pervaporation data for composite membranes showed a three-fold increase in the flux value, while the initially decreased separation factor subsequently showed a constant value. Overall, the pervaporation data suggested that the presence of silver nanoparticles benefited the dehydration process.

  18. Isolation of polyvinyl chloride degrading bacterial strains from ...

    African Journals Online (AJOL)

    In the present investigation, potent microbial strains degrading plastic constituting polymer polyvinyl chloride (PVC) were isolated using enrichment culture technique. To increase the chances of isolating such strain which could have adapted to metabolize plastic constituting polymers, samples were collected from different ...

  19. Electron beam immobilization of functionalized poly(vinyl methyl ether thin films on polymer surfaces – Towards stimuli responsive coatings for biomedical purposes

    Directory of Open Access Journals (Sweden)

    2011-11-01

    Full Text Available Thin films of poly(vinyl methyl ether (PVME were immobilized on polystyrene surfaces by low energy electron beam cross-linking. Structure retention as well as the thermo-responsive swelling behavior in aqueous media were studied by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR and spectroscopic ellipsometry respectively. The physical properties of the thermo-responsive coatings can be controlled in a wide range by adjusting the irradiation parameters. To allow for a variety of biomolecular functionalization strategies, the concept was extended by adding reactive sites to the system. For that purpose a mixture of PVME and the copolymer of PVME and maleic acid was applied, that possesses a similar stimuli-responsive behavior.

  20. In Situ Cross-Linking of Polyvinyl Alcohol Films

    Science.gov (United States)

    Philipp, W. H.; Shu, L. C.; May, C. E.

    1984-01-01

    Films or impregnated matrices readily made from aqueous polyvinyl alcohol solution. Controlled thickness films made by casting precise quantities of aqueous polymer solution on smooth surface, allowing water to evaporate and then removing film. Composite separators formed in similar fashion by impregnating cloth matrix with polyvinyl alcohol solution and drying composite. Insoluble thin hydrophilic membranes made from aqueous systems, and use of undesirable organic solvents not required.

  1. Direct methanol fuel cell based on poly(vinyl alcohol)/titanium oxide nanotubes/poly(styrene sulfonic acid) (PVA/nt-TiO 2/PSSA) composite polymer membrane

    Science.gov (United States)

    Yang, Chun-Chen; Chien, Wen-Chen; Li, Yingjeng James

    The high performance poly(vinyl alcohol)/titanium oxide nanotubes/poly(styrene sulfonic acid) (PVA/nt-TiO 2/PSSA) proton-conducting composite membrane is prepared by a solution casting method. The characteristic properties of these blend composite membranes are investigated by thermal gravimetric analysis (TGA), scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDX), micro-Raman spectroscopy, dynamic mechanical analysis (DMA), methanol permeability measurement and AC impedance method. It is found that the peak power densities of the DMFC with 1, 2, and 4 M CH 3OH fuels are 12.85, 23.72, and 10.99 mW cm -2, respectively, at room temperature and ambient air. Especially, among three methanol concentrations, the 2 M methanol shows the highest peak power density among three methanol concentrations. The results indicate that the air-breathing direct methanol fuel cell comprised of a novel PVA/nt-TiO 2/PSSA composite polymer membrane has excellent electrochemical performance and stands out as a viable candidate for applications in DMFC.

  2. Solid-phase extraction of cobalt(II) from lithium chloride solutions using a poly(vinyl chloride)-based polymer inclusion membrane with Aliquat 336 as the carrier.

    Science.gov (United States)

    Kagaya, Shigehiro; Cattrall, Robert W; Kolev, Spas D

    2011-01-01

    The extraction of cobalt(II) from solutions containing various concentrations of lithium chloride, hydrochloric acid, and mixtures of lithium chloride plus hydrochloric acid is reported using a poly(vinyl chloride) (PVC)-based polymer inclusion membrane (PIM) containing 40% (w/w) Aliquat 336 as a carrier. The extraction from lithium chloride solutions and mixtures with hydrochloric acid is shown to be more effective than extraction from hydrochloric acid solutions alone. The solution concentrations giving the highest amounts of extraction are 7 mol L(-1) for lithium chloride and 8 mol L(-1) lithium chloride plus 1 mol L(-1) hydrochloric acid for mixed solutions. Cobalt(II) is easily stripped from the membrane using deionized water. The cobalt(II) species extracted into the membrane are CoCl(4)(2-) for lithium chloride solutions and HCoCl(4)(-) for mixed solutions; these form ion-pairs with Aliquat 336. It is also shown that both lithium chloride and hydrochloric acid are extracted by the PIM and suppress the extraction of cobalt(II) by forming ion-pairs in the membrane (i.e. R(3)MeN(+)·HCl(2)(-) for hydrochloric acid and R(3)MeN(+)·LiCl(2)(-) for lithium chloride). 2011 © The Japan Society for Analytical Chemistry

  3. Photonics of a conjugated organometallic Pt-Ir polymer and its model compounds exhibiting hybrid CT excited states.

    Science.gov (United States)

    Soliman, Ahmed M; Fortin, Daniel; Zysman-Colman, Eli; Harvey, Pierre D

    2012-04-13

    Trans- dichlorobis(tri-n-butylphosphine)platinum(II) reacts with bis(2- phenylpyridinato)-(5,5'-diethynyl-2,2'-bipyridine)iridium(III) hexafluorophosphate to form the luminescent conjugated polymer poly[trans-[(5,5'-ethynyl-2,2'-bipyridine)bis(2- phenylpyridinato)-iridium(III)]bis(tri-n-butylphosphine)platinum(II)] hexafluorophosphate ([Pt]-[Ir])n. Gel permeation chromatography indicates a degree of polymerization of 9 inferring the presence of an oligomer. Comparison of the absorption and emission band positions and their temperature dependence, emission quantum yields, and lifetimes with those for models containing only the [Pt] or the [Ir] units indicates hybrid excited states including features from both chromophores. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Cross-linked polyvinyl alcohol and method of making same

    Science.gov (United States)

    Hsu, L. C.; Sheibley, D. W.; Philipp, W. H. (Inventor)

    1981-01-01

    A film-forming polyvinyl alcohol polymer is mixed with a polyaldehyde-polysaccharide cross-linking agent having at least two monosaccharide units and a plurality of aldehyde groups per molecule, perferably an average of at least one aldehyde group per monosaccharide units. The cross-linking agent, such as a polydialdehyde starch, is used in an amount of about 2.5 to 20% of the theoretical amount required to cross-link all of the available hydroxyl groups of the polyvinyl alcohol polymer. Reaction between the polymer and cross-linking agent is effected in aqueous acidic solution to produce the cross-linked polymer. The polymer product has low electrical resistivity and other properties rendering it suitable for making separators for alkaline batteries.

  5. Polyvinyl alcohol/starch composite nanofibers by bubble electrospinning

    Directory of Open Access Journals (Sweden)

    Liu Zhi

    2014-01-01

    Full Text Available Bubble electrospinning exhibits profound prospect of industrialization of macro/ nano materials. Starch is the most abundant and inexpensive biopolymer. With the drawbacks of poor strength, water resistibility, thermal stability and processability of pure starch, some biodegradable synthetic polymers such as poly (lactic acid, polyvinyl alcohol were composited to electrospinning. To the best of our knowledge, composite nanofibers of polyvinyl alcohol/starch from bubble electrospinning have never been investigated. In the present study, nanofibers of polyvinyl alcohol/starch were prepared from bubble electrospinning. The processability and the morphology were affected by the weight ratio of polyvinyl alcohol and starchy. The rheological studies were in agreement with the spinnability of the electrospinning solutions.

  6. Strategic modulation of the photonic properties of conjugated organometallic Pt-Ir polymers exhibiting hybrid CT-excited states.

    Science.gov (United States)

    Soliman, Ahmed M; Zysman-Colman, Eli; Harvey, Pierre D

    2015-04-01

    Polymer 6, ([trans-Pt(PBu3 )2 (C≡C)2 ]-[Ir(dFMeppy)2 (N^N)](PF6 ))n , (([Pt]-[Ir](PF6 ))n ; N^N = 5,5'-disubstituted-2,2'-bipyridyl; dFMeppy = 2-(2,4-difluoro-phenyl)-5-methylpyridine) is prepared along with model compounds. These complexes are investigated by absorption and emission spectroscopy and their photophysical and electrochemical properties are measured and compared with their corresponding non fluorinated complexes. Density functional theory (DFT) and time-dependent DFT computations corroborate the nature of the excited state as being a hybrid between the metal-to-ligand charge transfer ((1,3) MLCT) for the trans-Pt(PBu3 )2 (C≡CAr)2 unit, [Pt] and the metal-to-ligand/ligand-to-ligand' charge transfer ((1,3) ML'CT/LL'CT) for [Ir] with L = dFMeppy. Overall, the fluorination of the phenylpyridine group expectedly does not change the nature of the excited state but desirably induces a small blue shift of the absorption and emission bands along a slight decrease in emission quantum yields and lifetimes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Discoloration of Polyvinyl Butyral

    Science.gov (United States)

    Kim, Q.; Shumka, A.

    1986-01-01

    Report presents results of study of discoloration in polyvinyl butyral (PVB). Clear PVB gradually turns yellowish brown in simulated-aging tests and outdoor environmental tests. Discoloration severely reduces solar-cell output. Using methods of modern analytical chemistry - transmission absorption, Fourier transform infrared absorption, atomic absorption spectroscopy, and scanning-electron microscopy - study uncovered major cause of yellowing.

  8. Neutron scattering studies of bio-polymer-water systems: solvent mobility and collective excitations

    Energy Technology Data Exchange (ETDEWEB)

    Middendorf, H.D. [Oxford Univ. (United Kingdom). Clarendon Lab.

    1995-12-31

    The understanding of bio-polymer-water interactions at the molecular level depends crucially on a good characterization of dissipative processes and on accurate model parameters derived from experiments. The fundamental interest of this study is the coupling between hard and soft degrees of freedom, the dynamics of hydrogen-bonded molecular components and the effect of hydration on collective modes. The experiments and results discussed in this paper demonstrate how neutron scattering provides new insights into the dynamics of hydrated biomolecules. The ability to do diffraction-cum-spectroscopy over a large Q,{omega}-range corresponding to the space and time scales of bio-polymer-water interactions opens new ways which can be exploited for testing and refining theoretical models and simulations. Outstanding assets of neutron techniques in this context are the capability to probe diffusive as well as cooperative processes over scale lengths from about 1 to a few angstroms, together with the possibility of varying scattering contrast between the constituents of a heterogeneous system. Two systems are considered: a globular, slightly hydrated protein (phycocyanin) and a highly hydrated network of polysaccharide fibers. The phycocyanin results draw attention to the fact that the energy landscape of a hydrated biomolecule is very complex. Some of the concepts and models used in theoretical work will need to be refined substantially in order to accommodate data from experimental techniques capable of providing genuine spatio-temporal information. The characterization of hydration phenomena by two or three discrete relaxation times is too simplistic and the two-state models are inadequate to describe protein hydration. (J.S.). 39 refs., 10 figs.

  9. Fast field-induced dissociation and recombination of optical excitations in a pi-conjugated polymer

    CERN Document Server

    Lupton, J M; Baessler, H

    2003-01-01

    We present time resolved photoluminescence measurements on thin films of a phenyl-substituted poly(phenylene-vinylene) incorporated in a diode structure. Under reverse bias conditions rapid exciton dissociation is observed leading to luminescence quenching by up to 30%. In contrast, under forward bias conditions the initial quenching is substantially reduced due to shielding by space charges. At longer times thermally activated exciton quenching by injected polarons dominates the quenching process. At 3 ns after excitation, the external field is found to enhance the delayed luminescence. We attribute this to increased recombination of spatially correlated charge carrier pairs in the presence of the electric field, which are generated by exciton dissociation by bimolecular annihilation or on defect states.

  10. Role of polyvinyl alcohol in the conductivity behaviour of ...

    Indian Academy of Sciences (India)

    An attempt has been made in the present work to combine gel and composite polymer electrolyte routes together to form a composite polymeric gel electrolyte that is expected to possess high ionic conductivity with good mechanical integrity. Polyethylene glycol (PEG) based composite gel electrolytes using polyvinyl ...

  11. suitability of polyvinyl waste powder as partial replacement

    African Journals Online (AJOL)

    eobe

    from polymers of vinyl compound subsequently used to manufacture buil. Nigerian Journal of Techno ... (roofing sheets, windows, vinyl siding), consumer products, disposable packaging, and many every day products [15]. ..... [16] Thornton, J. (2002) “Environmental Impacts of. Polyvinyl Chloride Building Materials”. Healthy.

  12. Role of polyvinyl alcohol in the conductivity behaviour of ...

    Indian Academy of Sciences (India)

    poly(MMA–VC), poly(styrene–AN) and poly(styrene–butadiene) [8–11]. Within this framework, an attempt has been made in the present work to develop a polyethylene glycol-based polymer composite gel electrolyte, namely, polyethylene glycol–polyvinyl alcohol–NH4SCN system. This system has been studied on ac-.

  13. Synthesis and biocidal activity of modified poly(vinyl alcohol)

    OpenAIRE

    El-Refaie Kenawy; Mohamed H. El-Newehy; Fouad I. Abdel-Hay; Abd El-Raheem R. El-Shanshoury

    2014-01-01

    Functionalized polymers and their polymer nature give them more advantages than the corresponding small molecules. In this respect, polymeric ammonium and phosphonium salts were prepared by chemical modifications of poly(vinyl alcohol) (PVA) aiming to explore their antimicrobial activities against pathogenic bacteria and fungi. The modifications were performed by chloroacetylation with chloroacetyl chloride. Incorporation of the ammonium and phosphonium salts was conducted by the reaction of ...

  14. Synthesis and biocidal activity of modified poly(vinyl alcohol

    Directory of Open Access Journals (Sweden)

    El-Refaie Kenawy

    2014-07-01

    Full Text Available Functionalized polymers and their polymer nature give them more advantages than the corresponding small molecules. In this respect, polymeric ammonium and phosphonium salts were prepared by chemical modifications of poly(vinyl alcohol (PVA aiming to explore their antimicrobial activities against pathogenic bacteria and fungi. The modifications were performed by chloroacetylation with chloroacetyl chloride. Incorporation of the ammonium and phosphonium salts was conducted by the reaction of chloroacetylated poly(vinyl alcohol (CPVA with triethylamine (TEA, triphenylphosphine (TPP, and tributylphosphine (TBP. The antimicrobial activity of the polymers against variety of test microorganisms was examined by the cut plug and viable cell counting methods of shake cultures of 10 times dilute nutrient broth and Sabouraud’s media, seeded with the test microorganisms. It was found that the immobilized polymers exhibited antimicrobial activity against the Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Shigella sp. and Salmonella typhi and Gram positive bacteria (Bacillus subtilis and B. cereus and the dermatophyte fungus (Trichophyton rubrum. The growth inhibition of the test microorganisms (ratio of surviving cell number, M/C varied according to the composition of the active group in the polymer and the test organism. It increased by increasing the concentration of the polymer. Triphenyl phosphonium salt of the modified poly(vinyl alcohol exhibited the most biocidal activity against both Gram-negative and Gram-positive bacteria after 24 h.

  15. Polymers in cell encapsulation from an enveloped cell perspective

    NARCIS (Netherlands)

    de Vos, Paul; Lazarjani, Hamideh Aghajani; Poncelet, Denis; Faas, Marijke M.

    2014-01-01

    In the past two decades, many polymers have been proposed for producing immunoprotective capsules. Examples include the natural polymers alginate, agarose, chitosan, cellulose, collagen, and xanthan and synthetic polymers poly(ethylene glycol), polyvinyl alcohol, polyurethane, poly(ether-sulfone),

  16. Inkjet-printed Polyvinyl Alcohol Multilayers.

    Science.gov (United States)

    Salaoru, Iulia; Zhou, Zuoxin; Morris, Peter; Gibbons, Gregory J

    2017-05-11

    Inkjet printing is a modern method for polymer processing, and in this work, we demonstrate that this technology is capable of producing polyvinyl alcohol (PVOH) multilayer structures. A polyvinyl alcohol aqueous solution was formulated. The intrinsic properties of the ink, such as surface tension, viscosity, pH, and time stability, were investigated. The PVOH-based ink was a neutral solution (pH 6.7) with a surface tension of 39.3 mN/m and a viscosity of 7.5 cP. The ink displayed pseudoplastic (non-Newtonian shear thinning) behavior at low shear rates, and overall, it demonstrated good time stability. The wettability of the ink on different substrates was investigated, and glass was identified as the most suitable substrate in this particular case. A proprietary 3D inkjet printer was employed to manufacture polymer multilayer structures. The morphology, surface profile, and thickness uniformity of inkjet-printed multilayers were evaluated via optical microscopy.

  17. Research on ultrasonic excitation for the removal of drilling fluid plug, paraffin deposition plug, polymer plug and inorganic scale plug for near-well ultrasonic processing technology.

    Science.gov (United States)

    Wang, Zhenjun; Zeng, Jing; Song, Hao; Li, Feng

    2017-05-01

    Near-well ultrasonic processing technology attracts more attention due to its simple operation, high adaptability, low cost and no pollution to the formation. Although this technology has been investigated in detail through laboratory experiments and field tests, systematic and intensive researches are absent for certain major aspects, such as whether ultrasonic excitation is better than chemical agent for any plugs removal; whether ultrasound-chemical combination plug removal technology has the best plugs removal effect. In this paper, the comparison of removing drilling fluid plug, paraffin deposition plug, polymer plug and inorganic scale plug using ultrasonic excitation, chemical agent and ultrasound-chemical combination plug removal technology is investigated. Results show that the initial core permeability and ultrasonic frequency play a significant role in plug removal. Ultrasonic excitation and chemical agent have different impact on different plugs. The comparison results show that the effect of removing any plugs using ultrasound-chemicals composite plug removal technology is obviously better than that using ultrasonic excitation or chemical agent alone. Such conclusion proves that ultrasonic excitation and chemical agent can cause synergetic effects. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Structure and Electrical Study of New Chemically Modified Poly(vinyl chloride

    Directory of Open Access Journals (Sweden)

    F. Ammari

    2015-01-01

    Full Text Available The aim of this work was to study the structural and electrical properties of a new polymer obtained by functionalization of a commercial poly(vinyl chloride (PVC (Mw = 48000 by grafting aminoalkyl and aminoaryl groups. Modified poly(vinyl chloride was prepared in two steps. The structural properties of the polymer were systematically investigated by varieties of techniques as differential scanning calorimetric (DSC, thermogravimetry analysis (TG, X-ray diffraction (XRD, and Fourier transform infrared (FTIR spectroscopy. The electrical properties of the polymer were studied by electrochemical impedance spectroscopy (EIS.

  19. Incorporation of a Cationic Conjugated Polyelectrolyte CPE within an Aqueous Poly(vinyl alcohol) Sol

    DEFF Research Database (Denmark)

    Knaapila, Matti; Stewart, Beverly; Costa, Telma

    2016-01-01

    We report on a multiscale polymer-within-polymer structure of the cationic conjugated polyelectrolyte poly{[9,9-bis(6-N,N,N-trimethylammonium)hexyl]fluorene phenylene} (HTMAPFP) in aqueous poly(vinyl alcohol).(PVA) sol. Molecular dynamics simulations and small-angle neutron scattering (SANS) data...

  20. Charge and excitation dynamics in semiconducting polymer layers doped with emitters and charge carrier traps; Ladungstraeger- und Anregungsdynamik in halbleitenden Polymerschichten mit eingemischten Emittern und Ladungstraegerfallen

    Energy Technology Data Exchange (ETDEWEB)

    Jaiser, F.

    2006-06-15

    blend, the nature of the excited states as well as the method of the charge transport through the layer are of great importance to the transfer. Again, the charge carrier balance influences the emission. To characterize the trapping of charges in trap states, a method based on the measurement of transient photocurrents is enhanced. The results show that models developed for ordered systems can not simply be transferred to polymer systems with a high degree of disorder. Finally, time-resolved measurements of the phosphorescence decay in blends of polymers with organo-metallic compounds are shown. Usually, these systems contain more components that facilitate charge transport. Thus, triplets may be transferred from the phosphorescent dye other components of the film. Knowing the underlying interactions, unwanted processes can be suppressed. (orig.)

  1. Photo-Fries rearrangements of 1-naphthyl (R-2-phenylpropanoate in poly(vinyl acetate and ethyl acetate: influence of medium polarity and polymer relaxation on motions of singlet radical pairs

    Directory of Open Access Journals (Sweden)

    Xu Jinqi

    2006-01-01

    Full Text Available Both the regio- and stereo-chemistries of the photoreactions of 1-naphthyl (R-2-phenylpropanoate have been investigated in poly(vinyl acetate films in their glassy (at 5masculineC and melted (at 50masculineC states and in ethyl acetate. These results are compared with those from irradiations in polyethylene films and in n-hexane. The regioselectivity of the intermediate 1-naphthoxy/(R-2-phenylpropanoyl radical pair combinations is much higher in both the melt and glassy states of poly(vinyl acetate films than that in the melt state of completely amorphous polyethylene films, but the stereoselectivity of intermediate prochiral 1-naphthoxy/1-phenylethyl radical pair combinations is much lower in poly(vinyl acetate. The results emphasize the need to control the ratio between the rates of radical tumbling and translation, as well as the ratio between the rates of in-cage motions and cage-escape, if high stereo- and regio-selectivities of combination products are to be achieved. A mechanistic picture of how the radicals of the intermediate pairs are affected by and interact with the various media is advanced.

  2. Lithium ion conducting solid polymer blend electrolyte based on bio ...

    Indian Academy of Sciences (India)

    Lithium ion conducting polymer blend electrolyte films based on poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) with different Mwt% of lithium nitrate (LiNO3) salt, using a solution cast technique, have been prepared. The polymer blend electrolyte has been characterized by XRD, FTIR, DSC and impedance ...

  3. Electrospun polyvinyl alcohol-honey nanofibers

    OpenAIRE

    Wang Ping; He Ji-Huan

    2013-01-01

    This paper sugeests a method for fabrication of polyvinyl alcohol-honey nanofibers by electrospinning. Polyvinyl alcohol and honey are all biocompatible and environmentally friendly materials. This combination will lead to wide potential applications in various engineering fields.

  4. 75 FR 61175 - Polyvinyl Alcohol From Taiwan

    Science.gov (United States)

    2010-10-04

    ... COMMISSION Polyvinyl Alcohol From Taiwan AGENCY: United States International Trade Commission. ACTION... of polyvinyl alcohol, provided for in subheading 3905.30.00 of the Harmonized Tariff Schedule of the... of polyvinyl alcohol from Taiwan are being sold in the United States at less than fair value within...

  5. Polyvinyl acetate-based film coatings.

    Science.gov (United States)

    Kolter, K; Dashevsky, A; Irfan, Muhamad; Bodmeier, R

    2013-12-05

    Polyvinyl acetate-based colloidal aqueous polymer dispersion Kollicoat(®) SR 30 D results in coatings characterized by moderate swelling behaviour, lipophilicity, pH-independent permeability for actives and high flexibility to withstand mechanical stress and is therefore used for controlled release coating. The colloidal aqueous polymer dispersion of Kollicoat(®) SR 30 D can be easily processed due to an optimal low minimum film forming temperature (MFT) of 18 °C without plasticizer addition and a thermal after-treatment (curing) of coated pellets. The drug release from Kollicoat(®) SR 30 D coated pellets was almost pH independent. Drug release could be easily adjusted by coating level or addition of soluble pore forming polymers. Physically stable Kollicoat(®) SR 30 D dispersions were obtained with the water-soluble polymers Kollidon(®) 30 and Kollicoat(®) IR up to 50% w/w. The addition of only 10% w/w triethyl citrate as plasticizer improved the flexibility of the films significantly and allowed compaction of the pellets. The drug release was almost independent of the compression force and the pellet content of the tablets. The inclusion of various tableting excipients slightly affected the drug release, primarily because of a different disintegration rate of the tablets. A combination of Kollicoat(®) SR 30 D and Kollicoat(®) IR with higher coating levels>10 mg/cm(2) is a relatively new alternative to OROS system which does not require drilling. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Controlled Morphology of Porous Polyvinyl Butyral Nanofibers

    Directory of Open Access Journals (Sweden)

    Daniela Lubasova

    2011-01-01

    Full Text Available A simple and effective method for the fabrication of porous nanofibers based on the solvent evaporation methods in one-step electrospinning process from the commercial polyvinyl butyral (PVB is presented. The obtained nanofibers are prevalently amorphous with diameters ranging from 150 to 4350 nm and specific surface area of approximately 2–20 m2/g. Pore size with irregular shape of the porous PVB fibers ranged approximately from 50 to 200 nm. The effects of polymer solution concentration, composition of the solvents mixture, and applied voltage on fiber diameter and morphology were investigated. The theoretical approach for the choice of poor and good solvents for PVB was explained by the application Hansen solubility parameter (HSP and two-dimensional graph. Three basic conditions for the production of porous PVB nanofibers were defined: (i application of good/poor solvent mixture for spinning solution, (ii differences of the evaporation rate between good/poor solvent, and (iii correct ratios of good/poor solvent (v/v. The diameter of prepared porous PVB fibers decreased as the polymer concentration was lowered and with higher applied voltage. These nanofiber sheets with porous PVB fibers could be a good candidate for high-efficiency filter materials in comparison to smooth fibers without pores.

  7. Synergy effects of electric and magnetic fields on locally excited-state fluorescence of photoinduced electron transfer systems in a polymer film.

    Science.gov (United States)

    Awasthi, Kamlesh; Iimori, Toshifumi; Ohta, Nobuhiro

    2009-10-08

    Photoluminescence of electron donor-acceptor pairs that show photoinduced electron transfer (PIET) has been measured in a polymer film under simultaneous application of electric field and magnetic field. Fluorescence emitted from the locally excited state (LE fluorescence) of 9-methylanthracene (MAnt) and pyrene (Py) is quenched by an electric field in a mixture of 1,3-dicyanobenzene (DCB) with MAnt or Py, indicating that PIET from the excited state of MAnt or Py to DCB is enhanced by an electric field. Simultaneous application of electric and magnetic fields enhances the reverse process from the radical-ion pair produced by PIET to the LE fluorescent state of MAnt or Py. As a result, the electric-field-induced quenching of the LE fluorescence is reduced by application of the magnetic fields. Thus, the synergy effect of electric and magnetic fields is observed on the LE fluorescence of MAnt or Py. Exciplex fluorescence spectra resulting from PIET can be obtained by analyzing the field effects on photoluminescence spectra, even when the exciplex fluorescence is too weak to be determined from the steady-state or time-resolved photoluminescence spectra at zero field.

  8. Poly(vinyl alcohol)-heparin hydrogels as sensor catheter membranes

    NARCIS (Netherlands)

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

    1991-01-01

    Poly(vinyl alcohol)-heparin hydrogels with varying water content were synthesized for use as sensor catheter membranes. Films were cast from aqueous mixtures of poly(viny) alcohol) (PVA), a photosensitive cross-linker p-diazonium diphenyl amine polymer (PA), glutaraldehyde (GA) and heparin. After

  9. Preparation and Characterization of Atactic Poly(vinyl alcohol)/Platinum Nanocomposites by Electrospinning

    Science.gov (United States)

    Seok Lyoo, Won; Jae Lee, Young; Wook Cha, Jin; Jae Kim, Min; Woo Joo, Sang; Soon Gal, Yeong; Hwan Oh, Tae; Soo Han, Sung

    2010-06-01

    Poly(vinyl alcohol) (PVA)/platinum composite nanofibers were successfully prepared by the electrospinning method. Water-based colloidal platinum in a PVA solution was directly mixed without any chemical or structural modifications into PVA polymer fibers to form organic-inorganic composite nanofibers. The PVA/platinum composite nanofibers were characterized by field emission scanning electron microscopy (SEM).

  10. Raman Spectra and Dynamics of Thiocyanate Ion in Poly(Vinyl Alcohol)-KSCN Films

    Science.gov (United States)

    Gafurov, M. M.; Rabadanov, K. Sh.; Shabanov, N. S.; Tretinnikov, O. N.; Amirov, A. M.; Gadjimagomedov, S. Kh.

    2017-11-01

    Raman spectra of poly(vinyl alcohol)-potassium-thiocyanate films are studied. Parameters of vibrational and orientational relaxation of thiocyanate ion in the polymer matrix are determined. The character and rate of vibrational dephasing become identical to SCN- vibrations in aqueous solution at salt concentrations ≥0.3 M.

  11. Optical behaviour of swift heavy ions irradiated poly(vinyl alcohol) films

    Science.gov (United States)

    Sharma, Kalpana; Pal Chahal, Rishi; Mahendia, Suman; Tomar, Anil Kumar; Kumar, Shyam

    2013-05-01

    Polyvinyl alcohol films were irradiated to 90 MeV O 6+ and 150 MeV Si 14+ ions at fluence ranging from 1010 to 1012 ions/cm2. The observed changes in optical energy gap of this polymer have been investigated and results are tried to be explained in terms of energy transferred by the incident ions. It has been noticed that the value of optical energy gap decreases with increasing energy loss during the ion-polymer interaction process.

  12. Composition analysis and characterization of waste polyvinyl chloride (PVC) recovered from data cables.

    Science.gov (United States)

    Suresh, Sunil S; Mohanty, Smita; Nayak, Sanjay K

    2017-02-01

    Cables and wires are the indispensable parts of electronic equipments for transmission of both information and electricity. Nowadays, data cables are widely used in the computer equipments for sending information and they become waste once its life cycle is completed. However, recycling of cables and wires are mainly concentrating into the recovery of metals such as aluminium and copper, rather than other polymer present. Polymeric materials from the waste data cables are often disposed into landfills or incinerated, since they have only lower value in recycling yard. From the data cables collected, it has been estimated that the major constituents are copper (58.3%), polyvinyl chloride (19.9%) and polyethylene (16%). Similarly, polycarbonate (2.9%), silicon rubber (1.6%), steel (1.4%) and other material (0.4%) such as cotton cord were also present as minor components. Out of these, polyvinyl chloride is the dominant polymer present in data cables. Hence, the present work investigates the reprocessability of the polyvinyl chloride recovered from the data cables and deals with issues such as premature degradation during life cycle, assessment of plasticizers and degradation after reprocessing. Torque measurement studies using torque rheometer revealed further mechanical recycling possibilites of the recovered polyvinyl chloride. Besides, the applicability of melt blending technique for processing recovered polyvinyl chloride can be found out by analysing thermal behaviour by using thermogravimetric analysis, differential scanning calorimetry and heat distortion temperature. Copyright © 2016. Published by Elsevier Ltd.

  13. Chemical Modification of Poly(Vinyl Alcohol in Water

    Directory of Open Access Journals (Sweden)

    Houssein Awada

    2015-10-01

    Full Text Available Partial chemical modification of poly(vinyl alcohol (PVA was performed through tosylation followed by azidation. Amine functional PVA was also prepared by grafting propargylamine using click chemistry reaction. Through this approach, a tosyl group (a good leaving group, azide group (a group used in click chemistry and amine group (a group used for amidation were attached to PVA polymer chains. The three chemical modifications were performed in water. FTIR and XPS analysis confirmed the chemical modification after each step. Thermogravimetric analysis (TGA was used to study the thermal stability of the modified PVA.

  14. Stability of polyvinyl alcohol-coated biochar nanoparticles in brine

    Science.gov (United States)

    Griffith, Christopher; Daigle, Hugh

    2017-01-01

    This paper reports on the dispersion stability of 150 nm polyvinyl alcohol coated biochar nanoparticles in brine water. Biochar is a renewable, carbon based material that is of significant interest for enhanced oil recovery operations primarily due to its wide ranging surface properties, low cost of synthesis, and low environmental toxicity. Nanoparticles used as stabilizing agents for foams (and emulsions) or in nanofluids have emerged as potential alternatives to surfactants for subsurface applications due to their improved stability at reservoir conditions. If, however, the particles are not properly designed, they are susceptible to aggregation because of the high salinity brines typical of oil and gas reservoirs. Attachment of polymers to the nanoparticle surface, through covalent bonds, provides steric stabilization, and is a necessary step. Our results show that as the graft density of polyvinyl alcohol increases, so too does the stability of nanoparticles in brine solutions. A maximum of 34 wt% of 50,000 Da polyvinyl alcohol was grafted to the particle surface, and the size of the particles was reduced from 3500 nm (no coating) to 350 nm in brine. After 24 h, the particles had a size of 500 nm, and after 48 h completely aggregated. 100,000 Da PVA coated at 24 wt% on the biochar particles were stable in brine for over 1 month with no change in mean particle size of 330 nm.

  15. Stability of polyvinyl alcohol-coated biochar nanoparticles in brine

    Energy Technology Data Exchange (ETDEWEB)

    Griffith, Christopher, E-mail: cgriffith@utexas.edu; Daigle, Hugh [University of Texas at Austin, Department of Petroleum and Geosystems Engineering (United States)

    2017-01-15

    This paper reports on the dispersion stability of 150 nm polyvinyl alcohol coated biochar nanoparticles in brine water. Biochar is a renewable, carbon based material that is of significant interest for enhanced oil recovery operations primarily due to its wide ranging surface properties, low cost of synthesis, and low environmental toxicity. Nanoparticles used as stabilizing agents for foams (and emulsions) or in nanofluids have emerged as potential alternatives to surfactants for subsurface applications due to their improved stability at reservoir conditions. If, however, the particles are not properly designed, they are susceptible to aggregation because of the high salinity brines typical of oil and gas reservoirs. Attachment of polymers to the nanoparticle surface, through covalent bonds, provides steric stabilization, and is a necessary step. Our results show that as the graft density of polyvinyl alcohol increases, so too does the stability of nanoparticles in brine solutions. A maximum of 34 wt% of 50,000 Da polyvinyl alcohol was grafted to the particle surface, and the size of the particles was reduced from ~3500 nm (no coating) to 350 nm in brine. After 24 h, the particles had a size of ~500 nm, and after 48 h completely aggregated. 100,000 Da PVA coated at 24 wt% on the biochar particles were stable in brine for over 1 month with no change in mean particle size of ~330 nm.

  16. Controllable synthesis of Zn/Cd(ii) coordination polymers: dual-emissive luminescent properties, and tailoring emission tendency under varying excitation energies.

    Science.gov (United States)

    Xing, Kai; Fan, Ruiqing; Gao, Song; Wang, Xinming; Du, Xi; Wang, Ping; Fang, Ru; Yang, Yulin

    2016-03-21

    Based on a new asymmetric semi-rigid V-shaped tricarboxylate ligand 3-(2',3'-dicarboxylphenoxy)benzoic acid (H3dpob), a series of zinc/cadmium(ii) coordination polymers, {[Cd(Hdpob)(H2O)3]·H2O}n (1), [Cd(Hdpob)(bib)]n (2), [Zn(Hdpob)(bib)0.5]n (3), {[Cd1.5(dpob)(2,2'-bipy)]·0.5H2O}2n (4) and {[Cd3(dpob)2(4,4'-bipy)2]·3H2O}n (5) [bib = 1,4-bis(1-imidazolyl)benzene; 2,2'-bipy = 2,2'-bipyridine; 4,4'-bipy = 4,4'-bipyridine], have been successfully synthesized via hydro(solvo)thermal reactions. 1 forms a three dimensional (3D) supramolecular structure linked by two types of intermolecular hydrogen bonds based on zig-zag 1D chains, whereas 2 and 3 are obtained with a similar 2D layer structure by the same ligands and further connected into a 3D structure through hydrogen bonds. 4 displays a homochiral 2D structure though two achiral ligands 2,2'-bipy and H3dpob, which contains right-handed helical infinite chains. 5 is a 3D structure containing 2D metal-pyridine layer motifs, which are further pillared by beaded dpob(3-) ligands to complete the structure and form a 6-connected pcu (primitive cubic) net. In DMSO solvent, 1-5 illustrate dual-emission properties but have different low-energy emission (LE) intensities relatively. Extraordinarily, the difference resulting from central metals between 2 and 3 makes the intensity of LE dramatically enhanced and quenched. In this regard, the luminescence of 2 and 3 can be tuned between blue and green regions by varying the excitation light, and the tuning tendency can be tailored with inverse directions. Comparing their tunable-sensitivity to energy quantitatively, the theoretical calculation displays that 3 (4.29%) is little higher than 2 (3.59%) in a relative lower excitation wavelength zone. Meanwhile, five coordination polymers show distinct luminescence thermochromism in the solid state. When the temperature decreases from 298 K to 77 K, the red-shift from blue/green to the pure yellow light region is highlighted. The

  17. Eeonomer 200F®: A High-Performance Nanofiller for Polymer Reinforcement—Investigation of the Structure, Morphology and Dielectric Properties of Polyvinyl Alcohol/Eeonomer-200F® Nanocomposites for Embedded Capacitor Applications

    Science.gov (United States)

    Deshmukh, Kalim; Ahamed, M. Basheer; Deshmukh, Rajendra R.; Sadasivuni, Kishor Kumar; Ponnamma, Deepalekshmi; Pasha, S. K. Khadheer; AlMaadeed, Mariam Al-Ali; Polu, Anji Reddy; Chidambaram, K.

    2017-04-01

    In the present study, Eeonomer 200F® was used as a high-performance nanofiller to prepare polyvinyl alcohol (PVA)-based nanocomposite films using a simple and eco-friendly solution casting technique. The prepared PVA/Eeonomer nanocomposite films were further investigated using various techniques including Fourier transform infrared spectroscopy, x-ray diffraction, thermogravimetric analysis, polarized optical microscopy, scanning electron microscopy and mechanical testing. The dielectric behavior of the nanocomposites was examined over a broad frequency range from 50 Hz to 20 MHz and temperatures ranging from 40°C to 150°C. A notable improvement in the thermal stability of the PVA was observed with the incorporation of Eeonomer. The nanocomposites also demonstrated improved mechanical properties due to the fine dispersion of the Eeonomer, and good compatibility and strong interaction between the Eeonomer and the PVA matrix. A significant improvement was observed in the dielectric properties of the PVA upon the addition of Eeonomer. The nanocomposites containing 5 wt.% Eeonomer exhibited a dielectric constant of about 222.65 (50 Hz, 150°C), which was 18 times that of the dielectric constant (12.33) of neat PVA film under the same experimental conditions. These results thus indicate that PVA/Eeonomer nanocomposites can be used as a flexible high-k dielectric material for embedded capacitor applications.

  18. Solid polymer electrolyte lithium batteries

    Science.gov (United States)

    Alamgir, Mohamed; Abraham, Kuzhikalail M.

    1993-01-01

    This invention pertains to Lithium batteries using Li ion (Li.sup.+) conductive solid polymer electrolytes composed of solvates of Li salts immobilized in a solid organic polymer matrix. In particular, this invention relates to Li batteries using solid polymer electrolytes derived by immobilizing solvates formed between a Li salt and an aprotic organic solvent (or mixture of such solvents) in poly(vinyl chloride).

  19. Neutron attenuation characteristics of polyethylene, polyvinyl chloride, and heavy aggregate concrete and mortars.

    Science.gov (United States)

    Abdul-Majid, S; Othman, F

    1994-03-01

    Polyethylene and polyvinyl chloride pellets were introduced into concrete to improve its neutron attenuation characteristics while several types of heavy coarse aggregates were used to improve its gamma ray attenuation properties. Neutron and gamma ray attenuation were studied in concrete samples containing coarse aggregates of barite, pyrite, basalt, hematite, and marble as well as polyethylene and polyvinyl chloride pellets in narrow-beam geometry. The highest neutron attenuation was shown by polyethylene mortar, followed by polyvinyl chloride mortar; barite and pyrite concrete showed higher gamma ray attenuation than ordinary concrete. Broad-beam and continuous (infinite) medium geometries were used to study the neutron attenuation of samples containing polymers at different concentrations with and without heavy aggregates, the fitting equations were established, and from these the neutron removal coefficients were deduced. In a radiation field of neutrons and gamma rays, the appropriate concentration of polymer and heavy aggregate can be selected to give the optimum total dose attenuation depending on the relative intensities of each type of radiation. This would give much better design flexibility over ordinary concrete. The compressive strength tests performed on mortar and concrete samples showed that their value, in general, decreases as polymer concentration increases and that the polyvinyl chloride mortar showed higher values than the polyethylene mortar. For general construction purposes, the compression strength was considered acceptable in these samples.

  20. Catechol-derivatized poly(vinyl alcohol) as a coating molecule for magnetic nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Burnand, David [Adolphe Merkle Institute, University of Fribourg, Route de l' Ancienne Papéterie CP209, 1723 Marly 1 (Switzerland); Chemistry Department, University of Fribourg, Chemin du Musée 9, 1700 Fribourg (Switzerland); Monnier, Christophe A.; Redjem, Anthony [Adolphe Merkle Institute, University of Fribourg, Route de l' Ancienne Papéterie CP209, 1723 Marly 1 (Switzerland); Schaefer, Mark [Chemistry Department, University of Fribourg, Chemin du Musée 9, 1700 Fribourg (Switzerland); Rothen-Rutishauser, Barbara [Adolphe Merkle Institute, University of Fribourg, Route de l' Ancienne Papéterie CP209, 1723 Marly 1 (Switzerland); Kilbinger, Andreas, E-mail: andreas.kilbinger@unifr.ch [Chemistry Department, University of Fribourg, Chemin du Musée 9, 1700 Fribourg (Switzerland); Petri-Fink, Alke, E-mail: alke.fink@unifr.ch [Adolphe Merkle Institute, University of Fribourg, Route de l' Ancienne Papéterie CP209, 1723 Marly 1 (Switzerland); Chemistry Department, University of Fribourg, Chemin du Musée 9, 1700 Fribourg (Switzerland)

    2015-04-15

    Surface functionalization of superparamagnetic iron oxide nanoparticles (SPIONs) remains indispensable in promoting colloidal stability and biocompatibility. We propose a well-defined and characterized synthesis of a new catechol-functionalized RAFT (reversible addition–fragmentation chain transfer) poly(vinyl alcohol) polymer, which can be anchored onto hydrophobic SPIONs via a one-pot emulsion ligand exchange process. Both single and clustered nanoparticles are obtained and can be separated from each other. As clustered SPIONs are receiving increasing attention, this new macroligand might be of considerable interest for both basic and applied sciences. - Highlights: • We prepared well-defined polymer coated magnetic nanoparticles. • We used polyvinyl alcohol (PVA) as an alternative to commonly used plyethylene glycol (PEG). • We strongly anchored the polymer on the magnetic nanoparticles' surfaces. • We developed a one-pot emulsion ligand exchange process. • We obtained single coated particles and well defined magnetic clusters, which we successfully separated.

  1. Dancing on coke: smuggling cocaine dispersed in polyvinyl alcohol.

    Science.gov (United States)

    van Nuijs, Alexander L N; Maudens, Kristof E; Lambert, Willy E; Van Calenbergh, Serge; Risseeuw, Martijn D P; Van hee, Paul; Covaci, Adrian; Neels, Hugo

    2012-01-01

    Recent trends suggest that cocaine smugglers have become more and more inventive to avoid seizures of large amounts of cocaine transported between countries. We report a case of a mail parcel containing a dance pad which was seized at the Customs Department of Brussels Airport, Belgium. After investigation, the inside of the dance pad was found to contain a thick polymer, which tested positive for cocaine. Analysis was performed using a routine colorimetric swipe test, gas chromatography coupled with mass spectrometry and nuclear magnetic resonance spectroscopy. The polymer was identified as polyvinyl alcohol (PVA) and contained 18% cocaine, corresponding to a street value of € 20,000. Laboratory experiments showed that cocaine could be easily extracted from the PVA matrix. This case report reveals a new smuggling technique for the transportation of large amounts of cocaine from one country to another. © 2011 American Academy of Forensic Sciences.

  2. Contribution of Charges in Polyvinyl Alcohol Networks to Marine Antifouling.

    Science.gov (United States)

    Yang, Wufang; Lin, Peng; Cheng, Daocang; Zhang, Longzhou; Wu, Yang; Liu, Yupeng; Pei, Xiaowei; Zhou, Feng

    2017-05-31

    Semi-interpenetrated polyvinyl alcohol polymer networks (SIPNs) were prepared by integrating various charged components into polyvinyl alcohol polymer. Contact angle measurement, attenuated total reflection Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and tensile tests were used to characterize the physicochemical properties of the prepared SIPNs. To investigate the contribution of charges to marine antifouling, the adhesion behaviors of green algae Dunaliella tertiolecta and diatoms Navicula sp. in the laboratory and of the actual marine animals in field test were studied for biofouling assays. The results suggest that less algae accumulation densities are observed for neutral-, anionic-, and zwitterionic-component-integrated SIPNs. However, for the cationic SIPNs, despite the hydration shell induced by the ion-dipole interaction, the resistance to biofouling largely depends on the amount of cationic component because of the possible favorable electrostatic attraction between the cationic groups in SIPNs and the negatively charged algae. Considering that the preparation of novel nontoxic antifouling coating is a long-standing and cosmopolitan industrial challenge, the SIPNs may provide a useful reference for marine antifouling and some other relevant fields.

  3. Microwave synthesis of homogeneous and highly luminescent BCNO nanoparticles for the light emitting polymer materials

    Energy Technology Data Exchange (ETDEWEB)

    Iwasaki, Hideharu [Battery Materials Laboratory, Kurashiki Research Center, Kuraray Co., Ltd., 2045-1, Sakazu, Kurashiki, Okayama 710-0801 (Japan); Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima 739 8527 (Japan); Ogi, Takashi, E-mail: ogit@hiroshima-u.ac.jp [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima 739 8527 (Japan); Iskandar, Ferry [Department of Physics, Institute of Technology Bandung, Ganesha 10, Bandung 40132, West Java (Indonesia); Aishima, Kana; Okuyama, Kikuo [Department of Chemical Engineering, Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi Hiroshima 739 8527 (Japan)

    2015-10-15

    Nano-sized boron carbon oxynitride (BCNO) phosphors around 50 nm containing no rare earth metal and free from color heterogeneity were synthesized from mixtures of boric acid, urea, and citric acid by microwave heating with substantially shorter reaction times and lower temperatures than in the conventional BCNO preparation method such as electric-furnace heating. The emission wavelength of the phosphors varied with the mixing ratio of raw materials and it was found that lowering the proportion of urea to boric acid or citric acid tended to increase the internal quantum yield and shorten the emission wavelength under excitation at 365 nm. It was also found for the first time that a light-emitting polymer could be synthesized from a mixture of the prepared BCNO nanoparticles and a polyvinyl alcohol. This polymer composite exhibited uniform dispersion and stabilization of the luminescence and had a high internal quantum yield of 54%, which was higher than that of the phosphor alone. - Highlights: • Nano-sized BCNO phosphor was synthesized via microwave heating. • BCNO nanophosphor has homogeneous and high luminescence. • Emission wavelength was tunable by changing the ratio of precursor components. • BCNO nanophosphor can be easily dispersed in a polyvinyl alcohol. • BCNO–polymer composite exhibited uniform high internal quantum yield.

  4. Pilot plants for polymers: Safety considerations

    Energy Technology Data Exchange (ETDEWEB)

    Cordeiro, C.F.; Zvanut, C.W.

    1986-01-01

    Air Products and Chemicals is a major manufacturer of polyvinyl alcohol, vinyl acetate-ethylene emulsions and suspension PVC. Polyvinyl alcohol is a water soluble polymer and its primary end-uses are as a textile sizing agent and in adhesives. The emulsion products are used primarily in adhesives, paper, paints, and non-wovens. In order to support these business areas and to expand into new product lines, Air Products operates several polymer pilot plants. The safe operation of these pilot plants mandates careful attention to both design and operating procedures. Often, more care is needed in operating a polymer pilot plant than in other pilot plants or manufacturing facilities.

  5. Colloidal titration of aqueous zirconium solutions with poly(vinyl sulfate) by potentiometric endpoint detection using a toluidine blue selective electrode.

    Science.gov (United States)

    Sakurada, Osamu; Kato, Yasutake; Kito, Noriyoshi; Kameyama, Keiichi; Hattori, Toshiaki; Hashiba, Minoru

    2004-02-01

    Zirconium oxy-salts were hydrolyzed to form positively charged polymer or cluster species in acidic solutions. The zirconium hydrolyzed polymer was found to react with a negatively charged polyelectrolyte, such as poly(vinyl sulfate), and to form a stoichiometric polyion complex. Thus, colloidal titration with poly(vinyl sulfate) was applied to measure the zirconium concentration in an acidic solution by using a Toluidine Blue selective plasticized poly(vinyl chloride) membrane electrode as a potentiometric end-point detecting device. The determination could be performed with 1% of the relative standard deviation. The colloidal titration stoichiometry at pH < or = 2 was one mol of zirconium per equivalent mol of poly(vinyl sulfate).

  6. Influence of poly(vinyl alcohol) degree of hydrolysis in the production of quantum dots for bioconjugation; Influencia do grau de hidrolise do poli(alcool vinilico) na obtencao de pontos quanticos para bioconjugacao

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    Quantum dots, also known as semiconducting nanoparticle, are promising zero-dimensional advanced materials because of their nanoscale size and their quantum confinement properties. One of the fastest moving and most exciting interfaces of nanotechnology is the use of QDs in medicine, cell, and molecular biology, especially as biological detectors. In the case of these applications, it is crucial QDs synthesis based on aqueous routes and biocompatible stabilizers. In this sense, the main goal of this study was to obtain cadmium sulfide quantum dots from aqueous route using poly(vinyl alcohol), PVA, as capping agent, evaluating the influence of polymer degree of hydrolysis in nanoparticle formation and stabilization. UV-Vis spectroscopy was used to detect quantum dots production and size. The results have shown that PVA degree of hydrolysis is a crucial parameter to be controlled in order to obtain semiconducting nanoparticles in aqueous media for conjugation with biomolecules such as immunoglobulins, proteins, DNS, and oligonucleotides. (author)

  7. Study of Memory Alignment of Nematic Liquid Crystals on Polyvinyl Alcohol Coatings

    Science.gov (United States)

    Vetter, Peter; Ohmura, Yoshinori; Uchida, Tatsuo

    1993-09-01

    Polymer layers can cause memory alignment of nematic liquid crystals. We describe an experimental method to characterize this effect. We studied the temperature dependence of the memory alignment on polyvinyl alcohol coatings. We also investigated the influence of the time span during which the memory alignment is generated. We propose an adsorption-desorption mechanism by which we can explain our observations in a reasonable way.

  8. Solid polymer electrolytes

    Science.gov (United States)

    Abraham, Kuzhikalail M.; Alamgir, Mohamed; Choe, Hyoun S.

    1995-01-01

    This invention relates to Li ion (Li.sup.+) conductive solid polymer electrolytes composed of poly(vinyl sulfone) and lithium salts, and their use in all-solid-state rechargeable lithium ion batteries. The lithium salts comprise low lattice energy lithium salts such as LiN(CF.sub.3 SO.sub.2).sub.2, LiAsF.sub.6, and LiClO.sub.4.

  9. High spatial frequency periodic structures induced on ferric ion-doped Polyvinyl Pyrrolidone film by femtosecond laser pulses

    CERN Document Server

    Lai, Chen; Wang, Yunxia; Li, Qiang; Wu, Lijun

    2016-01-01

    Utilizing continues-wave or pulsed laser to induce nano-structures on various material surfaces is one significant method in nano-fabrication technology. In this report, we investigate the formation of high spatial frequency periodic structures on Polyvinyl Pyrrolidone (PVP) film by a linearly polarized femtosecond laser. Ferric (Fe) ions are introduced into the film to improve the photosensitivity. Regular nano-gratings with spatial periods at the range of 60-100nm, which are about one tenth of the irradiating wavelength, can be induced. The period direction of the nano-gratings is perpendicular to the polarization of the femtosecond laser. By tuning the laser energy and scanning speed, we find that the nano-gratings can be formed in a wide range of experimental parameters. As high laser energy can excite not only metals, but also semiconductors and polymers, we believe the formation of the nano-gratings is due to the interaction between the incident femtosecond laser and surface plasmons. The laser processa...

  10. Investigation of Polyvinyl Chloride and Thermoplastic Polyurethane Waste Blend Miscibility

    Directory of Open Access Journals (Sweden)

    Agnė LAUKAITIENĖ

    2013-12-01

    Full Text Available In this study the miscibility of polyvinyl chloride (PVC and poly-e-caprolactone based thermoplastic polyurethanes (TPU waste blends were investigated by dilute solution viscometry. The miscibility criteria a, Db, DB, and D[h] were used to assess the degree of miscibility of polymers in tetrahydrofuran solution. Also, to assess the miscibility and microstructure of PVC/TPU blends obtained by solution casting have been characterized by X-ray diffraction. The tensile strength and deformability properties varying on the blend composition were determined. It was found that PVC and TPU are partially miscible, their blend is amorphous and show two-phase structure. TPU changes the mechanical behaviour of PVC the blends. Increase of TPU content causes PVC elongation at break increase and tensile strength decreases. DOI: http://dx.doi.org/10.5755/j01.ms.19.4.3145

  11. Stimuli Responsive Poly(Vinyl Caprolactam Gels for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Kummara Madhusudana Rao

    2016-01-01

    Full Text Available Poly(vinyl caprolactam (PNVCL is one of the most important thermoresponsive polymers because it is similar to poly(N-isopropyl acrylamide. PNVCL precipitates from aqueous solutions in a physiological temperature range (32–34 °C. The use of PNVCL instead of PNIPAM is considered advantageous because of the assumed lower toxicity of PNVCL. PNVCL copolymer gels are sensitive to external stimuli, such as temperature and pH; which gives them a wide range of biomedical applications and consequently attracts considerable scientific interest. This review focuses on the recent studies on PNVCL-based stimuli responsive three dimensional hydrogels (macro, micro, and nano for biomedical applications. This review also covers the future outlooks of PNVCL-based gels for biomedical applications, particularly in the drug delivery field.

  12. Effect of Anionic Surfactant on the Thermo Acoustical Properties of Sodium Dodecyl Sulphate in Polyvinyl Alcohol Solution by Ultrasonic Method

    Directory of Open Access Journals (Sweden)

    S. Ravichandran

    2011-01-01

    Full Text Available The interaction of sodium dodecyl sulphate (SDS / poly(vinyl alcohol (PVA solution was studied by ultrasonic velocity measurements. Ultrasonic velocity, density, viscosity in mixtures of sodium dodecyl sulphate in polyvinyl alcohol was measured over the entire range of composition. From the experimental data, other related thermodynamic parameters, viz., adiabatic compressibility, intermolecular free length, surface tension, relative association, relaxation time, absorption coefficient and internal pressure were calculated. Formations of rods interfere with velocity of ultrasonic waves. Hence the ultrasonic velocity decreases with concentration. These results were interpreted in terms of polymer-surfactant complex reactions.

  13. Method of cross-linking polyvinyl alcohol and other water soluble resins

    Science.gov (United States)

    Phillipp, W. H.; May, C. E.; Hsu, L. C.; Sheibley, D. W. (Inventor)

    1980-01-01

    A self supporting sheet structure comprising a water soluble, noncrosslinked polymer such as polyvinyl alcohol which is capable of being crosslinked by reaction with hydrogen atom radicals and hydroxyl molecule radicals is contacted with an aqueous solution having a pH of less than 8 and containing a dissolved salt in an amount sufficient to prevent substantial dissolution of the noncrosslinked polymer in the aqueous solution. The aqueous solution is then irradiated with ionizing radiation to form hydrogen atom radicals and hydroxyl molecule radicals and the irradiation is continued for a time sufficient to effect crosslinking of the water soluble polymer to produce a water insoluble polymer sheet structure. The method has particular application in the production of battery separators and electrode envelopes for alkaline batteries.

  14. Chemical modification of poly(vinyl alcohol): evaluation of hydrophilic/lipophilic balance; Poli(alcool vinilico) modificado com cadeias hidrocarbonicas: avaliacao do balanco hidrofilo/lipofilo

    Energy Technology Data Exchange (ETDEWEB)

    Aranha, Isabele B.; Lucas, Elizabete F. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas Eloisa B. Mano]. E-mail: elucas@ima.ufrj.br

    2001-12-01

    Poly(vinyl alcohol) terpolymers have been obtained by reaction of partially hydrolized poly(vinyl alcohol) with different acid chlorides. The objective is the preparation of polymers with slight differences in their hydrophilic/lipophilic balance and in the interfacial activities of their solutions. The chemical modifications were characterized by means of {sup 1}H NMR and the polymer properties were evaluated in terms of changes in solubility and surface tension. By chemical modification, polymers with low percentage of hydrophobic group were obtained. The water-soluble polymers obtained did not have the surface tension of their solutions altered. The solubility of the modified polymers decreased markedly, even with low contents of hydrophobic groups. (author)

  15. 21 CFR 177.1670 - Polyvinyl alcohol film.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyvinyl alcohol film. 177.1670 Section 177.1670... Components of Single and Repeated Use Food Contact Surfaces § 177.1670 Polyvinyl alcohol film. Polyvinyl alcohol film may be safely used in contact with food of the types identified in § 176.170(c) of this...

  16. 75 FR 15726 - Polyvinyl Alcohol From Taiwan; Determination

    Science.gov (United States)

    2010-03-30

    ... COMMISSION Polyvinyl Alcohol From Taiwan; Determination On the basis of the record \\1\\ developed in the... Taiwan of polyvinyl alcohol provided for in subheading 3905.30.00 of the Harmonized Tariff Schedule of... threatened with material injury by reason of allegedly LTFV imports of polyvinyl alcohol from Taiwan...

  17. 76 FR 13982 - Antidumping Duty Order: Polyvinyl Alcohol From Taiwan

    Science.gov (United States)

    2011-03-15

    ... International Trade Administration Antidumping Duty Order: Polyvinyl Alcohol From Taiwan AGENCY: Import... Department is issuing an antidumping duty order on polyvinyl alcohol (PVA) from Taiwan. DATES: Effective Date... value in the antidumping duty investigation of PVA from Taiwan. See Polyvinyl Alcohol From Taiwan: Final...

  18. Two beam photoluminescence of PbS quantum dots in polyvinyl alcohol

    Science.gov (United States)

    Babu Pendyala, Naresh; Koteswara Rao, K. S. R.

    2010-11-01

    We report the effect of dual beam excitation on the photoluminescence (PL) from PbS quantum dots in polyvinyl alcohol by using two excitation lasers, namely Ar + (514.5 nm) and He-Ne laser (670 nm). Both sources of excitation gave similar PL spectra around 1.67 eV (related to shallow traps) and 1.1 eV (related to deep traps). When both lasers were used at the same time, we found that the PL induced by each of the lasers was partly quenched by the illumination of the other laser. The proposed mechanism of this quenching effect involves traps that are populated by one specific laser excitation, being photo-ionized by the presence of the other laser. Temperature, laser intensity and modulation frequency dependent quenching efficiencies are presented in this paper. This reversible modulation has potential for optical switching and memory device applications.

  19. In-situ cross linking of polyvinyl alcohol. [application to battery separator films

    Science.gov (United States)

    Philipp, W. H.; Hsu, L. C.; Sheibley, D. W. (Inventor)

    1981-01-01

    A method of producing a crosslinked polyvinyl alcohol structure, such as a battery separator membrane or electrode envelope is described. An aqueous solution of a film-forming polyvinyl alcohol is admixed with an aldehyde crosslinking agent a basic pH to inhibit crosslinking. The crosslinking agent, perferably a dialdehyde such as glutaraldehyde, is used in an amount of from about 1/2 to about 20% of the theoretical amount required to crosslink all of the hydroxyl groups of the polymer. The aqueous admixture is formed into a desired physical shape, such as by casting a sheet of the solution. The sheet is then dried to form a self-supporting film. Crosslinking is then effected by immersing the film in aqueous acid solution. The resultant product has excellent properties for use as a battery separator.

  20. Intramolecular crosslinking of poly(vinyl alcohol)

    NARCIS (Netherlands)

    Gebben, Bert; van den Berg, J.W.A.; Bargeman, Dick; Smolders, C.A.

    1985-01-01

    Poly(vinyl alcohol) is crosslinked in dilute solution (c=0.1 wt%) with glutaraldehyde. The reaction product is characterized by viscometry and gel permeation chromatography (g.p.c.). The intrinsic viscosity decreases with increasing degree of crosslinking and does not depend on temperature. G.p.c.

  1. Polyvinyl alcohol biodegradation under denitrifying conditions

    Czech Academy of Sciences Publication Activity Database

    Marušincová, H.; Husárová, L.; Růžička, J.; Ingr, M.; Navrátil, Václav; Buňková, L.; Koutný, M.

    2013-01-01

    Roč. 84, October (2013), s. 21-28 ISSN 0964-8305 Grant - others:GA ČR(CZ) GAP108/10/0200 Institutional support: RVO:61388963 Keywords : polyvinyl alcohol * biodegradation * denitrification * waste - water treatment * anaerobic * Steroidobacter Subject RIV: EI - Biotechnology ; Bionics Impact factor: 2.235, year: 2013

  2. Electrical conduction mechanism of polyvinyl chloride (PVC ...

    Indian Academy of Sciences (India)

    Abstract. The electrical conduction mechanism in polyvinyl chloride (PVC)– polymethyl methacrylate (PMMA) blend film has been studied at various temperatures in the range 313 K to 353 K. The results are presented in the form of I–V characteristics. Analysis has been made in the light of Poole–Frenkel, Fowler–Nordheim, ...

  3. Modification of polyvinyl alcohol surface properties by ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Pukhova, I.V., E-mail: ivpuhova@mail.ru [National Research Tomsk State University, 36 Lenin Ave, Tomsk 634050 (Russian Federation); Institute of High Current Electronics, 2/3 Akademichesky Ave, Tomsk 634055 (Russian Federation); Kurzina, I.A. [National Research Tomsk State University, 36 Lenin Ave, Tomsk 634050 (Russian Federation); Savkin, K.P. [Institute of High Current Electronics, 2/3 Akademichesky Ave, Tomsk 634055 (Russian Federation); Laput, O.A. [National Research Tomsk Polytechnic University, 30 Lenin Ave, Tomsk 634050 (Russian Federation); Oks, E.M. [Institute of High Current Electronics, 2/3 Akademichesky Ave, Tomsk 634055 (Russian Federation)

    2017-05-15

    We describe our investigations of the surface physicochemical properties of polyvinyl alcohol modified by silver, argon and carbon ion implantation to doses of 1 × 10{sup 14}, 1 × 10{sup 15} and 1 × 10{sup 16} ion/cm{sup 2} and energies of 20 keV (for C and Ar) and 40 keV (for Ag). Infrared spectroscopy (IRS) indicates that destructive processes accompanied by chemical bond (−C=O) generation are induced by implantation, and X-ray photoelectron spectroscopy (XPS) analysis indicates that the implanted silver is in a metallic Ag3d state without stable chemical bond formation with polymer chains. Ion implantation is found to affect the surface energy: the polar component increases while the dispersion part decreases with increasing implantation dose. Surface roughness is greater after ion implantation and the hydrophobicity increases with increasing dose, for all ion species. We find that ion implantation of Ag, Ar and C leads to a reduction in the polymer microhardness by a factor of five, while the surface electrical resistivity declines modestly.

  4. Spinning of hollow fiber ultrafiltration membranes from a polymer blend

    NARCIS (Netherlands)

    Wienk, I.M.; Wienk, I.M.; Olde scholtenhuis, F.H.A.; van den Boomgaard, Anthonie; Smolders, C.A.; Smolders, C.A.

    1995-01-01

    In this study the dry-wet spinning technique is used for the preparation of hollow fiber membranes. In the polymer solution a blend of two polymers, poly(ether sulfone) and poly(vinyl pyrrolidone), is used. The morphology of the membranes obtained is related to rheological characteristics and phase

  5. Sliding friction at poly(vinyl alcohol)-modified carbon nanotube interfaces

    Science.gov (United States)

    Zhang, Xiaohua

    2018-01-01

    The sliding friction between adjacent carbon nanotubes (CNTs) determines greatly the mechanical property of CNT assembly materials. In order to enhance the intertube friction, polymer molecules are often introduced between CNTs. This paper reveals a new energy dissipation mechanism for the deformed CNT contacts by poly(vinyl alcohol) (PVA). When PVA is introduced into a CNT bundle, most segments of the polymer chain lay on the grooves of adjacent CNTs, while several short segments span over the contact CNTs by inducing a structural deformation on the tubular structure. During the tube sliding, the deformation is recovered and a new one is formed at the next position, contributing to new energy dissipation to prevent the tube sliding. As a result, the friction force can be enhanced by up to eight-fold. This study indicates that a network of transverse polymer chains and longitudinal CNTs is important towards high mechanical properties.

  6. Improved film morphology reduces charge carrier recombination into the triplet excited state in a small bandgap polymer-fullerene photovoltaic cell

    Energy Technology Data Exchange (ETDEWEB)

    Di Nuzzo, Daniele; Shahid, Munazza; Gevaerts, Veronique S. [Molecular Materials and Nanosystems, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands); Dutch Polymer Institute (DPI), P.O. Box 902, 5600 AX Eindhoven (Netherlands); Aguirre, Aranzazu; Meskers, Stefan C.J.; Janssen, Rene A.J. [Molecular Materials and Nanosystems, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)

    2010-10-08

    The use of diiodooctane as processing additive for construction of PCPDTBT:PCBM solar cells results in a profound change in photophysical behavior of this blend. In the improved morphology obtained with the additive, recombination of charge carriers to the lowest triplet excited state is suppressed. This contributes to the boost in solar power conversion efficiency induced by the use of the processing agent. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  7. Block copolymers of poly(vinyl ethers) and poly(ethylene glycol) by means of the living cationic polymerization of vinyl ethers

    NARCIS (Netherlands)

    Loontjens, Ton; Derks, Frank; Kleuskens, Engelien

    1992-01-01

    If living poly(vinyl ethers) are terminated with a large excess of methanol, containing aqueous ammonia, well-defined products are obtained. If only a slight excess of methanol is used, aldehydes and coupling products are formed. However, termination with an excess of a hydroxy terminated polymer is

  8. Characterization of energetic and non-energetic polymers for laser ablation propulsion applications

    Science.gov (United States)

    Paturi, Prem Kiran; Chelikani, Leela; Billa, Narasimha Rao; Guthikonda, Nagaraju; Jana, Tushar; Acrhem Team; School Of Chemistry Team

    2015-06-01

    Energetic Polymers, considered to be cleaner, environmental friendly materials are one of the primary candidates for future plasma thrusters. For e.g., energetic hydroxyl terminated polybutadiene (HTPB) is being used as a binder for high-performance composite propellants. Understanding the conversion of optical energy to kinetic energy is essential in evaluating these materials as thrusters. Spatio-temporal evolution of laser ablative (LA) and blow-off (BO) shock waves (SW) during laser excitation provide a valuable insight into the energy release of the polymers. LASW and LBOSW during 7 ns laser pulse (532 nm, 10Hz) interaction with ~ 200 micron thick HTPB and its variants with energetic additives taken in the form of a sheet were studied simultaneously using defocused shadowgraphic imaging over 0.2 - 30 μs time scales. The results were compared with non-energetic polyvinyl chloride (PVC) under same experimental conditions. The SW was observed to propagate faster through the HTPB variant compared to HTPB. Appearance of LBOSW at different time scales for the polymers revealed the shock propagation characteristics through the polymers. The work is supported by Defence Research and Developement Organization, India through Grants-in-Aid Program.

  9. Poly(vinyl alcohol) nanocomposite films containing chemically exfoliated molybdenum disulfide

    Energy Technology Data Exchange (ETDEWEB)

    Batista Mancinelli, Ketlin Cristine; Lisboa, Fabio da Silva [Centro de Pesquisa em Quimica Aplicada - CEPESQ, Laboratorio de Quimica de Materiais Avancados, Universidade Federal do Parana, Departamento de Quimica, Caixa Postal 19081, 81531-980 Curitiba, PR (Brazil); Soares, Jaisa Fernandes [Laboratorio de Quimica Bioinorganica, Universidade Federal do Parana, Departamento de Quimica, Caixa Postal 19081, 81531-980 Curitiba, PR (Brazil); Zawadzki, Sonia Faria [Laboratorio de Polimeros Sinteticos, Universidade Federal do Parana, Departamento de Quimica, Caixa Postal 19081, 81531-980 Curitiba, PR (Brazil); Wypych, Fernando, E-mail: wypych@ufpr.br [Centro de Pesquisa em Quimica Aplicada - CEPESQ, Laboratorio de Quimica de Materiais Avancados, Universidade Federal do Parana, Departamento de Quimica, Caixa Postal 19081, 81531-980 Curitiba, PR (Brazil)

    2013-01-15

    Molybdenum disulfide (2H-MoS{sub 2}) was exfoliated in water after reaction with n-butyl-lithium. Using either alkaline or neutral conditions, different amounts of the resulting single-layer suspension were employed as filler for the production of poly(vinyl alcohol) films containing distinct disulfide contents. These nanocomposite films were obtained by wet casting and were further characterized by powder X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) and Raman spectroscopies. The mechanical properties of the films were also evaluated. Characterization studies revealed the attainment of homogeneous nanocomposite films in both alkaline and neutral conditions, indicating good distribution and interaction of the hydrophilic filler with the polyhydroxylated polymer. Improved Young's (tensile) modulus (+57%) and tensile strength (+9%) as well as reduced elongation (-78%) were achieved only when the neutral suspension of single layers was utilized. Increased MoS{sub 2} content diminished the crystallinity of the polymer, while enhanced mechanical properties were obtained in the presence of intermediate filler content (around 1 wt%). Highlights: Black-Right-Pointing-Pointer Molybdenum disulfide (2H-MoS{sub 2}) was chemically exfoliated in water. Black-Right-Pointing-Pointer MoS{sub 2} single-layer suspension was used as filler for poly(vinyl alcohol) films. Black-Right-Pointing-Pointer Increased MoS{sub 2} content diminished the crystallinity of the polymer. Black-Right-Pointing-Pointer Enhanced mechanical properties were obtained with intermediate filler content.

  10. Electrospun polyvinyl-alcohol nanofibers as oral fast-dissolving delivery system of caffeine and riboflavin

    DEFF Research Database (Denmark)

    Li, Xiaoqiang; Kanjwal, Muzafar Ahmed; Lin, Lin

    2013-01-01

    Fast-dissolving drug delivery systems were prepared by electrospinning using polyvinyl alcohol (PVA) as the filament-forming polymer and drug carrier. Caffeine and riboflavin were used as the model drugs. Scanning electron microscopy (SEM), Fourier-transform infrared (FTIR) and X-ray diffraction...... that PVA/caffeine and PVA/riboflavin nanofibrous mats had almost the same dissolution time (about 1.5 s) and wetting time (about 4.5 s). The release measurements indicated that drugs can be released in a burst manner (caffeine to an extent of 100% and riboflavin to an extent of 40% within 60 s) from...

  11. Study on properties of poly(vinyl alcohol/polyacrylonitrile blend film

    Directory of Open Access Journals (Sweden)

    Guoquan Zhu

    2013-01-01

    Full Text Available In this work, a series of poly(vinyl alcohol (PVA/polyacrylonitrile (PAN blend films with different PAN mole contents were prepared by casting the polymer blend solution in dimethylsulfoxide (DMSO. Surface morphologies of PVA/PAN blend films were analyzed by Scanning Electronic Microscopy (SEM and Atomic Force Microscopy (AFM. Thermal, mechanical, and chemical properties of PVA/PAN blend films were investigated by Differential Scanning Calorimetry (DSC, Thermogravimetric Analysis (TGA, Tensile Tests, and Surface Contact Angle Tests. The results showed that the introduction of PAN could exert marked effects on the properties of PVA films.

  12. Surface Adsorption and Replacement of Acid-Oxidized Single-Walled Carbon Nanotubes and Poly(vinyl pyrrolidone Chains

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2007-01-01

    Full Text Available Quartz crystal microbalance (QCM was used to investigate the adsorption of acid-oxidized single-walled carbon nanotubes (Ox-SWNTs and poly(vinyl pyrrolidone, PVP. It was found for the first time that Ox-SWNTs adsorbed onto the QCM electrode can be effectively replaced by PVP chains in an aqueous solution. This replacement process was also investigated by atomic force miscroscopic (AFM imaging, which shows good agreement with the QCM measurements. This study provides powerful tools for fundamental investigation of polymer-nanotube interactions and for controlled design/fabrication of functional polymer-nanotube surfaces for potential applications.

  13. Continuous microcellular foaming of polyvinyl chloride and compatibilization of polyvinyl chloride and polylactide composites

    Science.gov (United States)

    Shah, Bhavesh

    This dissertation focuses on overcoming existing limitations of WPCs which prevent them from realizing their full market potential. These limitations include: (i) lack of a continuous extrusion process for microcellular foaming of polyvinyl chloride (PVC) and its composites using supercritical fluids to reduce the high density of the WPCs, (ii) need for an efficient coupling agent for WPCs to overcome the poor compatibility between wood and plastic, and (iii) unproven use of wood as a filler for the biopolymer polylactide (PLA) to make "green" composites. These limitations were addressed through experimentation to develop a continuous extrusion process for microcellular foaming, and through surface modification of wood flour using natural coupling agents. The effects of wood flour, acrylic modifier and plasticizer content on the rheological properties of PVC based WPCs were studied using an extrusion capillary rheometer and a two-level factorial design. Wood flour content and acrylic modifier content were the major factors affecting the die swell ratio. Addition of plasticizer decreased the true viscosity of unfilled and filled PVC, irrespective of the acrylic modifier content. However, the addition of acrylic modifier significantly increased the viscosity of unfilled PVC but decreased the composite viscosity. Results of the rheological study were used to set baseline conditions for the continuous extrusion foaming of PVC WPCs using supercritical CO 2. Effects of material composition and processing conditions on the morphology of foamed samples were investigated. Foamed samples were produced using various material compositions and processing conditions, but steady-state conditions could not be obtained for PVC. Thus the relationships could not be determined. Incompatibility between wood flour and PVC was the focus of another study. The natural polymers chitin and chitosan were used as novel coupling agents to improve interfacial adhesion between the polymer matrix

  14. UV-responsive polyvinyl alcohol nanofibers prepared by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Khatri, Zeeshan, E-mail: zeeshan.khatri@faculty.muet.edu.pk [Department of Textile Engineering, Mehran University of Engineering and Technology, Jamshoro 76062 (Pakistan); Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan); Ali, Shamshad [Department of Textile Engineering, Mehran University of Engineering and Technology, Jamshoro 76062 (Pakistan); Department of Organic and Nano Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Khatri, Imran [Department of Entomology, Sindh Agriculture University, Tandojam (Pakistan); Mayakrishnan, Gopiraman [Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan); Kim, Seong Hun [Department of Organic and Nano Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, Ick-Soo, E-mail: kim@shinshu-u.ac.jp [Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan)

    2015-07-01

    Graphical abstract: - Highlights: • UV responsive PVA nanofibers were prepared via electrospinning. • Quick response codes were recorded multiple times on UV responsive nanofibers. • The rate of photo-coloration was found faster than the rate of photo-reversibility. - Abstract: We report UV-responsive polyvinyl alcohol (PVA) nanofibers for potential application for recording and erasing quick response (QR) codes. We incorporate 1′-3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2′-(2H)-indole] (indole) and,3-dihydro-1,3,3-trimethylspiro [2H-indole-2,3′-[3H] phenanthr [9,10-b] (1,4) oxazine] (oxazine) into PVA polymer matrix via electrospinning technique. The resultant nanofibers were measured for recording–erasing, photo-coloration and thermal reversibility. The rate of photo-coloration of PVA–indole nanofibers was five times higher than the PVA–oxazine nanofibers, whereas the thermal reversibility found to be more than twice as fast as PVA–oxazine nanofibers. Results showed that the resultant nanofibers have very good capability of recording QR codes multiple times. The FTIR spectroscopy and SEM were employed to characterize the electrospun nanofibers. The UV-responsive PVA nanofibers have great potentials as a light-driven nanomaterials incorporated within sensors, sensitive displays and in optical devices such as erasable and rewritable optical storage.

  15. Self Nucleation and Crystallization of Poly(vinyl alcohol)

    Science.gov (United States)

    Thomas, David; Cebe, Peggy

    Polyvinyl alcohol (PVA) is a hydrophilic, biodegradable, semi-crystalline polymer with uses ranging from textiles to medicine. Film samples of PVA were investigated to assess crystallization and melting behavior during self-nucleation experiments, and thermal degradation, using differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis, respectively. TG results show that degradation occurred at temperatures close to the observed peak melting temperature of 223 C. Using conventional DSC, PVA was heated at a rate of 10 C/min to various self-nucleation temperatures, Ts, within its melting range, briefly annealed, cooled and reheated. Three distinct crystallization regimes were observed upon cooling, depending upon self nucleation temperature. At low values of Ts, below 227 C, PVA only partially melts; residual crystal anneals while new, less perfect crystals form during cooling. Between 228 C and 234 C, PVA was found to crystallize exclusively by self-nucleation. For Ts above 235 C the PVA melts completely. Fast scanning chip-based calorimetry was used to heat and cool at 2000 K/s, to prevent degradation. Results of self nucleation experiments using fast scanning and conventional DSC will be compared. NSF DMR-1206010.

  16. Excited states

    CERN Document Server

    Lim, Edward C

    1974-01-01

    Excited States, Volume I reviews radiationless transitions, phosphorescence microwave double resonance through optical spectra in molecular solids, dipole moments in excited states, luminescence of polar molecules, and the problem of interstate interaction in aromatic carbonyl compounds. The book discusses the molecular electronic radiationless transitions; the double resonance techniques and the relaxation mechanisms involving the lowest triplet state of aromatic compounds; as well as the optical spectra and relaxation in molecular solids. The text also describes dipole moments and polarizab

  17. KOMPARASI KUAT TEKAN KOMPOSIT BERBAHAN DASAR SERBUK LIMBAH KACA DENGAN PEREKAT POLIMER POLYURETHANE DAN POLYVINYL ACETATE

    Directory of Open Access Journals (Sweden)

    MP Aji

    2013-07-01

    Full Text Available Komposit berbahan dasar serbuk limbah kaca telah dihasilkan dengan perekat polimer polyurethane (PU dan polyvinyl acetate (PVAc. Komposit dengan perekat polimer PU memiliki kuat tekan 36 MPa dengan fraksi optimum perekat adalah 30% berat. Komposit dengan perekat polimer PVAc memiliki kuat tekan yang lebih rendah dari perekat polimer PU, yaitu 10 MPa pada fraksi perekat 10 persen berat. Gugus fungsi urethane yang terbentuk dari gugus fungsi isosianat yang reaktif dan hidroksil menjadi perekat yang baik untuk limbah kaca yang didominasi oleh bahan silika (SiO2. Daya rekat polimer pada serbuk kaca ditentukan banyaknya kontak perekat dengan silika. Hasil uji kuat tekan diestimasi dengan persamaan sederhana. Hasil estimasi menunjukan bahwa komposit dengan perekat polimer PU memiliki kontak dengan partikel limbah kaca lebih banyak dari perekat PVAc. Kontak perekat dengan serbuk kaca merepresentasi daya adhesif. Hasil ini didukung dari pengujian porositas komposit dimana perekat polimer PU dengan kontak partikel yang tinggi memiliki porositas yang jauh lebih rendah dari perekat polimer PVAc sehingga komposit dengan perekat polimer PU memiliki kuat tekan yang lebih baik. Composite made from waste glass powder has been produced with polymer adhesive polyurethane (PU and polyvinyl acetate (PVAC. Composites with a polymer adhesive PU has a compressive strength of 36 MPa with optimum adhesive fraction of 30% of weight. Meanwhile, polymer composite with PVAc adhesive has a lower compressive strength than PU adhesive polymer, that is 10 MPa at adhesive fraction of 10 percent of weight. Functional group of urethane formed from reactive isocyanate and hydroxyl is turning out to be a good adhesive for glass waste material dominated by silica (SiO2. Polymer adhesion on glass powder is determined by contact of adhesive with silica. Compressive strength test results are estimated with a simple equation. Estimation results show that composite with PU adhesive

  18. Biodesulphurization of gasoline by Rhodococcus erythropolis supported on polyvinyl alcohol.

    Science.gov (United States)

    Fatahi, A; Sadeghi, S

    2017-05-01

    A new biodesulphurization (BDS) method has been considered using Rhodococcus erythropolis supported on polyvinyl alcohol (PVA) for BDS of thiophene as a gasoline sulphur model compound in n-hexane as the solvent, subsequently this biocatalyst has been applied to BDS of gasoline samples. The obtained results according to UV-Spectrophotometer analysis at 240 nm showed that 97·41% of thiophene at the optimum condition of primary concentration 80 mg l-1 , pH = 7, by 0·1 g of biocatalyst in 30°C and after 20 h of contact time has been degraded. These optimum conditions have been applied to gasoline BDS and the biodegradation of gasoline thiophenic compounds have been investigated by gas chromatography-mass spectrometry (GC-MS). According to GC-MS, thiophene and its 2-methyl, 3-methyl and 2- ethyl derivatives had acceptable biodegradation efficiencies of about 26·67, 21·03, 23·62% respectively. Also, benzothiophene that has been detected in a gasoline sample had 38·89% biodegradation efficiency at optimum conditions, so biomodification of PVA by R. erythropolis produces biocatalysts with an active metabolism that facilitates the interaction of bacterial strain with gasoline thiophenic compounds. The morphology and surface functional groups of supported R. erythropolis on PVA have been investigated by scanning electron microscope (SEM) and FT-IR spectroscopy respectively. SEM images suggest some regular layered shape for the supported bacteria. FT-IR spectra indicate a desirable interaction between bacterial cells and polymer supports. Also, the recovery of biocatalyst has been investigated and after three times of using in BDS activity, its biocatalytic ability had no significant decreases. The biomodification of polyvinyl alcohol by Rhodococcus erythropolis described herein produces a new biocatalyst which can be used for significantly reducing the thiophenic compounds of gasoline and other fossil fuels. The immobilization process is to increase the

  19. Development and characterization of polyvinyl alcohol stabilized polylactic acid/ZnO nanocomposites

    Science.gov (United States)

    Restrepo, I.; Benito, N.; Medinam, C.; Mangalaraja, R. V.; Flores, P.; Rodriguez-Llamazares, S.

    2017-10-01

    The present work is focused on the development of polylactic acid/ZnO (PLA/ZnO) polymer nanocomposite through a melt blending route. Previously, the ZnO nanoparticles were coated with polyvinyl alcohol (PVA) via a solvothermal method. The morphology of PVA coated ZnO nanostructures and the formation of polymer nanocomposites were identified through transmission electron microscopy analysis. Thermogravimetric analysis showed that PVA coated ZnO(c) nanoparticles incorporated into the PLA matrix exhibited better thermal stability, suggesting that PVA could be acting as a strong stabilizing agent for ZnO nanoparticles. The tensile strength, elastic modulus, strain at maximum strength and the maximum strain were extracted through stress–strain relations.

  20. Interaction between vegetable oil based plasticizer molecules and polyvinyl chloride, and their plasticization effect

    Science.gov (United States)

    Haryono, Agus; Triwulandari, Evi; Jiang, Pingping

    2017-01-01

    Plasticizer molecules are low molecular weight compounds that are widely used in polymer industries especially in polyvinyl chloride (PVC) resin. As an additive in PVC resin, the important role of plasticizer molecules is to improve the flexibility and processability of PVC by lowering the glass transition temperature (Tg). However, the commercial plasticizer like di(2-ethylhexyl)phthalate (DEHP) is known to cause liver cancer, at least in laboratory rats. DEHP can leach out from PVC into blood, certain drug solutions and fatty foods, which has been detected in the bloodstream of patients undergoing transfusion. Vegetable oil based plasticizers have some attractive properties such as non-toxic, bio-degradable, good heat and light stability, renewable resources, and environmentally friendly. Here we discussed the main results and development of vegetable oil based plasticizer, and especially palm oil based plasticizer. The interaction between plasticizer and polymer was discussed from the properties of the plasticized polymeric material.

  1. Compatibilizing role of carbon nanotubes in poly(vinyl alcohol)/starch blend

    KAUST Repository

    Jose, Jobin Vinodh

    2014-10-03

    Polymer nanocomposites based on poly(vinyl alcohol)/starch blend and carbon nanotubes (CNT) were prepared by solution mixing, followed by casting. Glycerol was used as a plasticizer and added in the starch dispersion. The uniform dispersion of CNT in water before mixing with PVA/starch blend, was achieved by using an Ultrasonicator probe. The composites were characterized by measurement of tensile properties, thermal analysis, FE-SEM, TEM, XRD studies, and water uptake. It was observed that the decrease in tensile strength, modulus, and elongation at break on addition of starch into PVA can be arrested by incorporation of CNT. The strong physical bonding such as hydrogen bonding among the hydroxyl groups of polymer components and oxygen containing groups on CNT surface resulted in a more tortuous path for the water to follow, lowering of water uptake. Thermal analysis and spectroscopic images showed an increase in blend homogeneity in the presence of CNT.

  2. Effects of PVA(Polyvinyl Alcohol) on Supercooling Phenomena of Water

    Science.gov (United States)

    Kumano, Hiroyuki; Saito, Akio; Okawa, Seiji; Takizawa, Hiroshi

    In this paper, effects of polymer additive on supercooling of water were investigated experimentally. Poly-vinyl alcohol (PVA) were used as the polymer, and the samples were prepared by dissolving PVA in ultra pure water. Concentration, degree of polymerization and saponification of PVA were varied as the experimental parameters. The sample was cooled, and the temperature at the instant when ice appears was measured. Since freezing of supercooled water is statistical phenomenon, many experiments were carried out and average degrees of supercooling were obtained for each experimental condition. As the result, it was found that PVA affects nucleation of supercooling and the degree of supercooling increases by adding the PVA. Especially, it is found that the average degree of supercooling increases and the standard deviation of average degree of supercooling decreases with increase of degree of saponification of PVA. However, the average degree of supercooling are independent of the degree of polymerization of PVA in the range of this study.

  3. Complex compound polyvinyl alcohol-titanic acid/titanium dioxide

    Science.gov (United States)

    Prosanov, I. Yu.

    2013-02-01

    A complex compound polyvinyl alcohol-titanic acid has been produced and investigated by means of IR and Raman spectroscopy, X-ray diffraction, and synchronous thermal analysis. It is claimed that it represents an interpolymeric complex of polyvinyl alcohol and hydrated titanium oxide.

  4. suitability of polyvinyl waste powder as partial replacement

    African Journals Online (AJOL)

    eobe

    SUITABILITY OF POLYVINYL WASTE P. OF POLYVINYL WASTE P. FOR CEMENT IN CON. E. Ikponmwosa. Ikponmwosa. 1, 3DEPARTMENT OF CIVIL AND E. 2DEPARTMENT OF. E-mail addresses: mail addresses: mail addresses: 1 eikponmwosa@unilag.edu.n. ABSTRACT. This work presents the results of investigation.

  5. The effects of shear and particle shape on the physical adsorption of polyvinyl pyrrolidone on carbon nanoparticles.

    Science.gov (United States)

    Vo, Minh D; Papavassiliou, Dimitrios V

    2016-08-12

    The effects of shear and particle shape on the physical adsorption of a polymer (polyvinyl pyrrolidone, PVP) on carbon nanoparticles (CNPs) were studied with dissipative particle dynamics (DPD) methods. It was found that the conformation of the polymer during adsorption and desorption from the nanoparticle can be classified into three possible types, i.e. adsorbed, shear-affected and separated, depending on the magnitude of the shear rate in the flow. Spherical and graphene sheet-shaped particles with adsorbed PVP were manipulated in a Couette flow to determine the threshold shear rates leading to changes in the polymer adsorption state. It was found that the polymer was stably adsorbed under higher shear conditions for graphene sheets. In addition, the end-to-end distance and the radius of gyration of the polymer adsorbate was clearly related to the adsorption state, as the polymer underwent a transition from adsorbed to the separated state when the shear rate increased. The critical shear rate at which the polymer desorbed from the surface could be useful in applications where nanoparticles can be used as a molecular delivery system. The physical adsorption and desorption of the same polymer molecules on a flat surface were also investigated. The desorption of the polymer from the flat surface occurred when the shearing force was stronger than the attraction between the PVP and the surface.

  6. The effect of bacterial cellulose on the shape memory behavior of polyvinyl alcohol nanocomposite hydrogel

    Science.gov (United States)

    Pirahmadi, Pegah; Kokabi, Mehrdad

    2018-01-01

    Most research on shape memory polymers has been confined to neat polymers in their dry state, while, some hydrogel networks are known for their shape memory properties. Hydrogels have low glass transition temperatures which are below 100°C depend on the content of water. But they are usually weak and brittle, and not suitable for structural applications due to their low mechanical strengths because of these materials have large amount of water (>50%), so they could not remember original shape perfectly. Bacterial cellulose nanofibers with perfect properties such as high water holding capacity, high crystallinity, high tensile strength and good biocompatibility can dismiss all the drawbacks. In the present study, polyvinyl alcohol/bacterial cellulose nanocomposite hydrogel prepared by repetitive freezing-thawing method. The bacterial cellulose was used as reinforcement to improve the mechanical properties and stimuli response. Differential scanning calorimetry was employed to obtain the glass transition temperature. Nanocomposite morphology was characterized by field-emission scanning electron microscopy and mechanical properties were investigated by standard tensile test. Finally, the effect of bacterial cellulose nanofiber on shape memory behavior of polyvinyl alcohol/bacterial cellulose nanocomposite hydrogel was investigated. It is found that switching temperature of this system is the glass transition temperature of the nano domains formed within the system. The results also show increase of shape recovery, and shape recovery speed due to presence of bacterial cellulose.

  7. Permanent hydrophilic modification of polypropylene and poly(vinyl alcohol) films by vacuum ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Belmonte, Guilherme Kretzmann [Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Charles, German [Centro de Química Aplicada (CEQUIMAP), Facultad de Ciencias Químicas, Unversidad Nacional de Córdoba, Haya de la Torre y Medina Allende, Edificio de Ciencias II, Ciudad Universitaria, Córdoba 5000 (Argentina); Strumia, Miriam Cristina [Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, IPQA-Conicet, Haya de la Torre y Medina Allende, Edificio de Ciencias II, Ciudad Universitaria, Córdoba 5000 (Argentina); Weibel, Daniel Eduardo, E-mail: danielw@iq.ufrgs.br [Instituto de Química, Universidade Federal do Rio Grande do Sul (UFRGS), Avenida Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil)

    2016-09-30

    Highlights: • Polypropylene and Poly(vinyl alcohol) were surface modified by vacuum ultraviolet (VUV) irradiation. • The hydrophilicity of the treated films was permanent and resisted aging for several months. • Grafting of styrene monomer was only observed in the VUV irradiated regions. • The obtained results showed the potential in the use of VUV treatment for surface modification and processing of polymers which lack chromophores in the UV region. - Abstract: Polypropylene (PP) and Poly(vinyl alcohol) (PVA) both synthetics polymers but one of them biodegradable, were surface modified by vacuum ultraviolet (VUV) irradiation. After VUV irradiation in an inert nitrogen atmosphere, the films were exposed to oxygen gas. The treated films were characterized by water contact angle measurements (WCA), optical profilometry, FTIR-ATR, XPS, UPS and NEXAFS techniques. PP and PVA VUV-treated films reached superhydrophilic conditions (WCAs <10°) in about 30 min of irradiation under our experimental conditions. It was observed that when the WCAs reached about 35–40° the hydrophilicity was permanent in both polymers. These results contrasted with typical plasma treatments were a rapid hydrophobic recovery with aging time is usually observed. UPS and XPS data showed the presence of new functionalities on the PP and PVA surfaces that were assigned to COO, C=O, C−O and C=C functional groups. Finally, grafting of styrene (ST) as a typical monomer was tested on PP films. It was confirmed that only in the VUV irradiated region an efficient grafting of ST or polymerized ST was found. Outside the irradiated regions no ST grafted was observed. Our results showed the potential use of VUV treatment for surface modification and processing of polymers which lack chromophores in the UV region.

  8. Polymer dots grafted TiO2 nanohybrids as high performance visible light photocatalysts.

    Science.gov (United States)

    Li, Gen; Wang, Feng; Liu, Peng; Chen, Zheming; Lei, Ping; Xu, Zhongshan; Li, Zengxi; Ding, Yanfen; Zhang, Shimin; Yang, Mingshu

    2018-01-18

    As a new member of carbon dots (CDs), Polymer dots (PDs) prepared by hydrothermal treatment of polymers, usually consist of the carbon core and the connected partially degraded polymer chains. This type of CDs might possess aqueous solubility, non-toxicity, excellent stability against photo-bleaching and high visible light activity. In this research, PDs were prepared by a moderate hydrothermal treatment of polyvinyl alcohol, and PDs grafted TiO2 (PDs-TiO2) nanohybrids with TiOC bonds were prepared by a facile in-situ hydrothermal treatment of PDs and Ti (SO4)2. Under visible light irradiation, the PDs-TiO2 demonstrate excellent photocatalytic activity for methyl orange degradation, and the photocatalytic rate constant of PDs-TiO2 is 3.6 and 9.5 times higher than that of pure TiO2 and commercial P25, respectively. In addition, the PDs-TiO2 exhibit good recycle stability under UV-Vis light irradiation. The interfacial TiOC bonds and the π-conjugated structures in PDs-TiO2 can act as the pathways to quickly transfer the excited electrons between PDs and TiO2, therefore contribute to the excellent photocatalytic activity. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Structure and physical properties of high amorphous polyvinyl alcohol/clay composites

    Science.gov (United States)

    Russo, P.; Speranza, V.; Vignali, A.; Tescione, F.; Buonocore, G. G.; Lavorgna, M.

    2015-12-01

    Recently a high amorphous polyvinyl alcohol (HAVOH) which can be easily melt processed has been patented and commercialized with the trade name G-Polymer. In this work, we report on the characterization of clay-G-Polymer composites obtained by melt processing of HAVOH with two commercial chemically-modified organoclays, Cloisite 15A and Cloisite 30B. Results show that the extent of polymer intercalation in the layered clay structure as well as the thermal and mechanical properties of the obtained composites depend on the nature of clay organo-modifier, i.e a quaternary ammonium salt of dimethyl dehydrogenated tallow for Cloisite 15A and an alkyl ammonium salt of bis-(2-hydroxyethyl)methyl tallow for Cloisite 30B. In particular Cloisite 15A, which is only slightly intercalated by the polymer during melt compounding, contributes to enhance glass transition temperature and mechanical properties of the resulting composites. On the contrary, Cloisite 30B which is significantly intercalated by the interacting polymer macromolecules, disturbs to some extent the H-bonding network established within the polymeric matrix thus showing a reduction of thermal and mechanical properties.

  10. Effect of side chain length and degree of polymerization on the decomposition and crystallization behaviour of chlorinated poly(vinyl ester) oligomers

    Energy Technology Data Exchange (ETDEWEB)

    Heinze, D.; Mang, Th. [Aachen University of Applied Sciences, Heinrich-Mussmann-Str. 1, 52428 Jülich (Germany); Popescu, C., E-mail: crisan.popescu@kao.com [KAO Germany GmbH, Pfungstädterstr. 98-100, 64297 Darmstadt (Germany); Weichold, O., E-mail: weichold@ibac.rwth-aachen.de [Institute of Building Materials Research, Schinkelstr. 3, 52062 Aachen (Germany)

    2016-08-10

    Highlights: • Thermal behaviour of telomerized polyvinyl esters is investigated. • Thermal stability relies mainly on the contribution of side chains. • At equal molecular weights thermal stability is dictated by length of side chain. • Increasing the length of side chains improves also the packing degree of polymer. - Abstract: Four members of a homologous series of chlorinated poly(vinyl ester) oligomers CCl{sub 3}–(CH{sub 2}CH (OCO(CH{sub 2}){sub m}CH{sub 3})){sub n}–Cl with degrees of polymerization of 10 and 20 were prepared by telomerisation using carbon tetrachloride. The number of side chain carbon atoms ranges from 2 (poly(vinyl acetate) to 18 (poly(vinyl stearate)). The effect of the n-alkyl side chain length and of the degree of polymerization on the thermal stability and crystallization behaviour of the synthesized compounds was investigated. All oligomers degrade in two major steps by first losing HCl and side chains with subsequent breakdown of the backbone. The members with short side chains, up to poly(vinyl octanoate), are amorphous and show internal plasticization, whereas those with high number of side chain carbon atoms are semi-crystalline due to side-chain crystallization. A better packing for poly(vinyl stearate) is also noticeable. The glass transition and melting temperatures as well as the onset temperature of decomposition are influenced to a larger extent by the side chain length than by the degree of polymerization. Thermal stability is improved if both the size and number of side chains increase, but only a long side chain causes a significant increase of the resistance to degradation. This results in a stabilization of PVAc so that oligomers from poly(vinyl octanoate) on are stable under atmospheric conditions. Thus, the way to design stable, chlorinated PVEs oligomers is to use a long n-alkyl side chain.

  11. IMMOBILIZATION OF LYSOZYME IN POLYVINYL ALCOHOL CRYOGEL

    Directory of Open Access Journals (Sweden)

    S. S. Dekina

    2014-06-01

    Full Text Available The lysozyme immobilization in cryogel of polyvinyl alcohol and physico-chemical properties of obtained preparation was investigated. Hydrolytic activity of lysozyme was determined by bacteriolytic method, using Micrococcus lysodeikticus cells acetone powder as substrate. Protein content was determined by the Lowry–Hartree method. Immobilization of lysozyme was conducted by entrapment in polyvinyl alcohol gel with subsequent cycles of freezing-thawing. Antimicrobial activity was studied by standard disk-diffusional method. The hydrogel filmic coatings with antimicrobial action, insoluble at physiological conditions, with quantitative retaining of protein and hydrolytic activity of lysozyme were obtained. The product is characterized by the widened pH-profile of activity at acidic pH values, stability in acidic medium (pH 5.5 and at storage. Its antimicrobial action against Staphylococcus aureus ATCC 25923 F-49, Pseudomonas aeruginosa 415, Escherichia coli 055 K 59912/4 and Candida albicans ATCC 885-653 was noted. The proposed method of lysozyme immobilization allows to obtain stable, highly effective product with antimicrobial activity, prospective for usage in biomedical investigations.

  12. Effects of Molecular Weight upon Irradiation-Cross-Linked Poly(vinyl alcohol)/Clay Aerogel Properties.

    Science.gov (United States)

    Chen, Hong-Bing; Zhao, Yan; Shen, Peng; Wang, Jun-Sheng; Huang, Wei; Schiraldi, David A

    2015-09-16

    Facile fabrication of mechanically strong poly(vinyl alcohol) (PVOH)/clay aerogel composites through a combination of increasing polymer molecular weights and gamma irradiation-cross-linking is reported herein. The aerogels produced from high polymer molecular weights exhibit significantly increased compressive moduli, similar to the effect of irradiation-induced cross-linking. The required irradiation dose for fabricating strong PVOH composite aerogels with dense microstructure decreased with increasing polymer molecular weight. Neither thermal stability nor flammability was significantly changed by altering the polymer molecular weight or by modest gamma irradiation, but they were highly dependent upon the polymer/clay ratio in the aerogel. Optimization of the mechanical, thermal, and flammability properties of these composite aerogels could therefore be obtained by using relatively low levels of polymer, with very high polymer molecular weight, or lower molecular weight coupled with moderate gamma irradiation. The facile preparation of strong, low flammability aerogels is an alternative to traditional polymer foams in applications where fire safety is important.

  13. Irradiation of polyvinyl alcohol and polyvinyl pyrrolidone blended hydrogel for wound dressing

    Energy Technology Data Exchange (ETDEWEB)

    Razzak, Mirzan T.; Darwis, Darmawan; Zainuddin; Sukirno

    2001-07-01

    Polyvinyl alcohol and polyvinyl pyrrolidone (PVA-PVP) blended hydrogel for wound dressing has been prepared by using gamma rays irradiation technique. The gel fraction, mechanical properties, the water content and water absorption performance of the hydrogels were measured. It was found that the gel fraction increases with increasing irradiation dose but never reaches 100% of gel. The PVA/PVP blended hydrogel has a water content in the range between 60% and 80% and water absorption between 40% and 250%. The water vapor transmission rate value (WVTR) of the PVA/PVP blended hydrogel varies between 50 and 200 g/m{sup 2}/h. The hydrogel could be considered as good barrier against microbes. According to in vitro assessment it was found that the PVA/PVP blended hydrogel was very useful material that can meet the efficacy requirement and its healing rate was comparable with sterilized gauze and sofratulle.

  14. Investigation Of Laser-Polymer Interaction By Time Resolved Emission Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Urech, L.; Lippert, T.; Wokaun, A.

    2005-03-01

    The plasma emission properties of poly(vinyl chloride) (PVC), glycidyl azide polymer (GAP) and poly(vinyl nitrate) (PVN) have been investigated. The plasma temperature and electron density were calculated from the recorded spectra. For the energetic polymers (GAP and PVN) the plasma temperature decreased faster and had a higher maximum value. The fastest rate of decrease in the electron density was observed for GAP, whereas PVN and PVC had similar, but slower density reduction. For all polymers an increase in the plasma temperature within the first {mu}s was observed. (author)

  15. Experimental studies of the dynamic mechanical response of a single polymer chain

    DEFF Research Database (Denmark)

    Thormann, Esben; Evans, Drew R.; Craig, Vincent S. J.

    2006-01-01

    The high-frequency and low-amplitude dynamic mechanical response from a single poly(vinyl alcohol) chain was investigated. Modification of a commercial atomic force microscope enabled high-frequency and low-amplitude periodic deformations of polymer chains during extension to be performed....... Such an experiment has previously been considered untenable due to hydrodynamic and viscous effects, but we introduce here a method to isolate the response of the polymer from the hydrodynamic response. For periodic deformations with frequencies of 400-2000 Hz and amplitudes of 0.55-16.9 nm, we find that the dynamic...... mechanical response from poly(vinyl alcohol) does not differ from its static response. This result is not unexpected as poly(vinyl alcohol) is a highly flexible polymer with intramolecular relaxation processes taking place on a short time scale. The choice of a polymer with a fast relaxation allows its...

  16. Excited Delirium

    Directory of Open Access Journals (Sweden)

    Takeuchi, Asia

    2011-02-01

    Full Text Available Excited (or agitated delirium is characterized by agitation, aggression, acute distress and sudden death, often in the pre-hospital care setting. It is typically associated with the use of drugs that alter dopamine processing, hyperthermia, and, most notably, sometimes with death of the affected person in the custody of law enforcement. Subjects typically die from cardiopulmonary arrest, although the cause is debated. Unfortunately an adequate treatment plan has yet to be established, in part due to the fact that most patients die before hospital arrival. While there is still much to be discovered about the pathophysiology and treatment, it is hoped that this extensive review will provide both police and medical personnel with the information necessary to recognize and respond appropriately to excited delirium. [West J Emerg Med. 2011;12(1:77-83.

  17. Effect of gamma radiation on the poly(vinyl alcohol); Efeito da radiacao gama no poli(vinil alcool)

    Energy Technology Data Exchange (ETDEWEB)

    Terence, M.C. [Universidade Presbiteriana Mackenzie, Sao Paulo, SP (Brazil). Dept. de Engenharia de Materiais; Guedes, S.M.L. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes], e-mail: mterence@usp.br

    2000-07-01

    The poly(vinyl alcohol) (PVAL) is a polymer used as bio material. The PVAL was used as ocular insert and may be used as a drug delivery system (DDS) for pair PVAL/gancyclovir, where the last one is used for treatment of people with retinitis caused by cytomegalovirus. These inserts are crosslinked systems. The crosslink was induced by gamma radiation applied in polymer. The samples of PVAL was irradiated by gamma rays with doses in the range 0 to 100 kGy. On irradiated PVAL samples was observed a low yellowness, attributed to the formation of polymeric radicals that are stable in the structure of the polymer, from radiolysis of PVAL. (author)

  18. Strong stokes and upconversion luminescence from ultrasmall Ln(3+)-doped BiF3 (Ln=Eu3+, Yb3+/Er3+) nanoparticles confined in a polymer matrix.

    Science.gov (United States)

    Sarkar, Shyam; Dash, Armita; Mahalingam, Venkataramanan

    2014-02-01

    Heavy metal fluorides like BiF3 as a host for lanthanide ions are of interest as bismuth is the only heavy metal that is nontoxic. In this work, we report the synthesis of highly water-dispersible ultrasmall BiF3 nanoparticles about 6 nm in size within a poly(vinyl pyrrolidone) matrix by a hydrothermal method. Microscopy analysis reveals that the nanoparticles are well separated and confined within the polymer network. These nanoparticles were found to be excellent hosts for lanthanide (Ln(3+)) ions. Through suitable Ln(3+) doping, BiF3 exhibits strong emissions in the visible region upon both UV and near infrared (NIR) excitations. The non-toxicity of both bismuth and PVP can be advantageous for the potential use of BiF3 nanoparticles in drug delivery and bioimaging. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Lithium ion conducting solid polymer blend electrolyte based on bio ...

    Indian Academy of Sciences (India)

    vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) with different Mwt% of lithium nitrate (LiNO3) salt, using a solution cast technique, have been prepared. The polymer blend electrolyte has been characterized by XRD, FTIR, DSC and ...

  20. Polyvinyl alcohol cross-linked with two aldehydes

    Science.gov (United States)

    Sheibley, D. W.; Rieker, L. L.; Hsu, L. C.; Manzo, M. A. (Inventor)

    1982-01-01

    A film forming polyvinyl alcohol resin is admixed, in aqueous solution, with a dialdehyde crosslinking agent which is capable of crosslinking the polyvinyl alcohol resin and a water soluble acid aldehyde containing a reactive aldehyde group capable of reacting with hydroxyl groups in the polyvinyl alcohol resin and an ionizable acid hydrogen atom. The dialdehyde is present in an amount sufficient to react with from 1 to 20% by weight of the theoretical amount required to react with all of the hydroxyl groups of the polyvinyl alcohol. The amount of acid aldehyde is from 1 to 50% by weight, same basis, and is sufficient to reduce the pH of the aqueous admixture to 5 or less. The admixture is then formed into a desired physical shape, such as by casting a sheet or film, and the shaped material is then heated to simultaneously dry and crosslink the article.

  1. Relative toxicity of pyrolysis products of some synthetic polymers

    Science.gov (United States)

    Hilado, C. J.; Slattengren, C. L.; Furst, A.; Kourtides, D. A.; Parker, J. A.

    1976-01-01

    Nineteen samples of synthetic polymers were evaluated for relative toxicity in the course of characterizing materials intended for aircraft interior applications. The generic polymers included ABS, chlorinated PVC, polycarbonate, polyphenylene oxide, polyphenylene sulfide, polysulfone, polyaryl sulfone, polyether sulfone, polybismaleimide, and polyvinyl fluoride. Test results are presented, and compared in relative rankings with similar results on cellulosic materials and other synthetic polymers. Under these test conditions, the samples of synthetic polymers were either comparable to or significantly less toxic than the samples of commercial cellulosic materials.

  2. 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.

  3. Bacterial sunscreen: layer-by-layer deposition of UV-absorbing polymers on whole-cell biosensors.

    Science.gov (United States)

    Eby, D Matthew; Harbaugh, Svetlana; Tatum, Randi N; Farrington, Karen E; Kelley-Loughnane, Nancy; Johnson, Glenn R

    2012-07-17

    UV-protective coatings on live bacterial cells were created from the assembly of cationic and UV-absorbing anionic polyelectrolytes using layer-by-layer (LbL) methodology. A cationic polymer (polyallylamine) and three different anionic polymers with varying absorbance in the UV range (poly(vinyl sulfate), poly(4-styrenesulfonic acid), and humic acid) were used to encapsulate Escherichia coli cells with two different green fluorescent protein (GFP) expression systems: constitutive expression of a UV-excitable GFP (GFPuv) and regulated expression of the intensely fluorescent GFP from amphioxus (GFPa1) through a theophylline-inducible riboswitch. Riboswitches activate protein expression after specific ligand-RNA binding events. Hence, they operate as a cellular biosensor that will activate reporter protein synthesis after exposure to a ligand target. E. coli cells coated with UV-absorbing polymers demonstrated enhanced protection of GFP stability, metabolic activity, and viability after prolonged exposure to radiation from a germicidal lamp. The results show the effectiveness of LbL coatings to provide UV protection to living cells for biotechnological applications.

  4. Analysis of Distribution of Polyvinyl Alcohol Hydrogel Nanocrystalline by using SAXS Synchrotron

    Science.gov (United States)

    Sunaryono; Taufiq, A.; Mufti, N.; Hidayat, N.; Rugmai, S.; Soontaranon, S.; Putra, E. G. R.; Darminto

    2017-05-01

    Polyvinyl alcohol (PVA) hydrogel has been successfully synthesized through freezing-thawing (F-T) process by using time-variation. This work is aimed to investigate the distribution of nanocrystalline from the hydrogel. Fourier Transform Infrared (FTIR) Spectroscopy, Differential Thermal Analysis/Thermogravimetric (DTA/TG), and Synchrotron Small-Angle X-ray Scattering (SAXS) were used as the instruments in characterizing the PVA hydrogel, respectively to observe the frequency of absorption, thermal degradation, and structural dimensions. The functional groups which represent the PVA polymer chains were verified on the wavenumber of 1450-1480 cm-1 and 850-870 cm-1 which is in accordance with the stretching of -CH2 vibration mode. The absorption band of PVA polymer chains was also found on the wavenumber of 1090-1150 cm-1 which is in accordance with the stretching of carboxyl vibration mode (CO), and this wavenumber gave a contribution towards the crystallinity of PVA polymer. Furthermore, the PVA polymer only interacted with the distilled water in the sample of PVA hydrogel without experiencing any chemical interactions between the PVA polymer and other substances. Meanwhile, the graphic of PVA hydrogel thermal degradation shows three thermal decompositions which are indicated by three areas in which there was sample weight loss. The second decomposition with sample weight loss was equivalent to 61.62%-73.04% occurred at the temperature of 282-376 °C which became the highest sample weight loss due to polymer chain degradation. Teubner-Strey and Beaucage models were used to analyze the characterization of structural dimension and distribution of PVA Hydrogel nanocrystalline with SAXS Synchrotron. With a high compatibility between the model data and the experiment, the average structural dimension of PVA hydrogel nanocrystalline is the equivalent of 3.96 nm, with an inter-crystalline average distance of 16.9 nm. These results indicate that PVA hydrogel is very

  5. Water resistance and thermal properties of polyvinyl alcohol-starch fiber blend film

    Science.gov (United States)

    Salleh, M. S. N.; Nor, N. N. Mohamed; Mohd, N.; Draman, S. F. Syed

    2017-02-01

    The growing attention of starch fiber (SF) has led to the innovation of Polyvinyl Alcohol-SF (PVA-SF) blends. This blend is regarded as the biodegradable material which aims to reduce the accumulation of synthetic polymer solid waste derived from petroleum. In this study, the thermal blending characterizations of PVA-SF were investigated by differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The water resistance of the blend was also evaluated to study the polarity of the blends. The blend was prepared by plasticizing the polyvinyl alcohol with glycerol and distilled water with the addition of starch fiber. The incorporation of SF to the blends was at 10 wt% to 50 wt% composition. Based on the thermal analysis, PVA-SF blends were suitable for processing at high temperatures, which can be seen by the shifted onset degradation temperature to a higher temperature. This is because cyclic hemiacetals which were provided by SF can act to prevent the thermal attacks. Conversely, increasing the starch fiber proportion to the film blend reduce the endothermic peak amplitude in the DSC thermogram. It was found that PVA-SF blend at the higher composition of SF had the highest water resistance. This may be attributed to the content of fibre in SF which is hydrophilic.

  6. Utilization of Cellulose from Pineapple Leaf Fibers as Nanofiller in Polyvinyl Alcohol-Based Film

    Directory of Open Access Journals (Sweden)

    Kendri Wahyuningsih

    2016-08-01

    Full Text Available Cellulose from pineapple leaf fibers as one of the natural polymer which has biodegradable property in a nanometer’s scale, can be formed as a filler in composite of Poly(vinyl Alcohol/PVA is expected to increase the physical, thermal, and barrier properties of composite films similar to conventional plastic. The aim of this study was to examine the effect of fibrillation of cellulose fibers from pineapple leaf fibers using a combined technique of chemical-mechanical treatments, to investigate the reinforcing effect of concentration of nanocellulose fibrils in the polyvinyl alcohol (PVA matrix on physical properties, thermal properties, water vapor transmission rate, light transmittance and morphological with and without addition of glycerol. Nanocellulose was made from cellulose of pineapple leaf fiber using wet milling (Ultra Fine Grinder. The composite film production was carried out by using casting solution method by mixing PVA solution with nanocellulose (10-50% and glycerol (0-1%. The characterization of film covered physical properties (thickness, moisture content and density, thermal properties, permeability (WVTR, light transmittance, morphology, and crystallinity. Nanocellulose from pineapple leaf fibers was produced by Ultra Fine Grinder shows that the size reduction process was accurate. Nanocellulose addition on PVA composite film was affected to increasing the physical, thermal, and barrier properties. Meanwhile, decreasing the percentage of composite film transmittance, thus the transparency decrease (opaque. Water vapor transmission rate (WVTR the film was increased with increasing glycerol concentration, but the physical and thermal properties was decreased.

  7. Radiation damage of polymers in ultrasonic fields

    Energy Technology Data Exchange (ETDEWEB)

    Anbalagan, Poornnima

    2008-07-01

    Radiation damage has always been a topic of great interest in various fields of sciences. In this work, an attempt is made to probe into the effect of subthreshold ultrasonic waves on the radiation damage created by irradiation of deuterons in polymer samples wherein the polymer samples act as model systems. Two equal volumes of radiation damage were produced in a single polymer sample wherein a standing wave of ultrasound was introduced into one. Three polymers namely, Polycarbonate, Polymethylmethacrylate and Polyvinyl chloride were used in this work. Four independent techniques were used to analyze the irradiated samples and visualize the radiation damage. Interferometric measurements give a measure of the refractive index modulation in the irradiated sample. Polymers, being transparent, do not absorb in the visible region of the electromagnetic spectrum. UV-Vis absorption spectroscopy shows absorption peaks in the visible region in irradiated polymer samples. Ion irradiation causes coloration of polymers. The light microscope is used to measure the absorption of white light by the irradiated polymers. Positron annihilation spectroscopy is used to obtain a measure of the open volume created by irradiation in polymers. A comparison between the irradiated region and the region exposed to ultrasonic waves simultaneously with irradiation in a polymer sample shows the polymer specific influence of the ultrasonic standing wave. (orig.)

  8. Thermodynamic characteristics of the interaction between methanol and Keplerate-type poly(vinyl alcohol)-polyoxomolybdate composites

    Science.gov (United States)

    Ostroushko, A. A.; Adamova, L. V.; Eremina, E. V.

    2017-08-01

    The interaction between methanol vapors and composite film samples of polyvinyl alcohol-porous keplerate nanocluster polyoxomolybdate Mo132 is studied by means of equilibrium interval sorption performed gravimetrically and using thermodynamic cycle calculations. Isotherms of methanol sorption by the films are obtained, and the concentration dependences of the average Gibbs energies of the interaction between methanol and films are calculated, along with the Gibbs energy and entropy of the interaction between polyoxometalate and the polymer. Micrographs of the studied composite films are presented.

  9. A solid state NMR investigation of char forming processes in polymer degradation

    CERN Document Server

    Dick, C M

    2002-01-01

    A detailed knowledge of the condensed phase chemistry occurring in polymers exposed to elevated temperatures is crucial to understanding the behaviour of polymers exposed to fire. This is particularly true when trying to reduce polymer flammability by means of promoting char-forming reactions. Until recently, however, structural information on highly crosslinked chars and their precursors has been difficult to obtain, and as a consequence many degradation workers have merely labelled degradation residues as 'intractable'. However, the application of solid state NMR techniques developed in our laboratories for the structural characterisation of coals has provided a considerable insight into the structure and chemistry of polymer chars formed under both oxidative and non-oxidative conditions. A series of polymers including poly(vinyl chloride), poly(vinyl acetate), polyurethanes, polychloropene, cis and trans polyisoprene have been studied. These polymers have been used to describe the application of quantitati...

  10. Effects of poly-vinyl alcohol on supercooling phenomena of water

    Energy Technology Data Exchange (ETDEWEB)

    Kumano, Hiroyuki; Hirata, Tetsuo; Kudoh, Tomoya [Department of Mechanical Systems Engineering, Shinshu University, 4-17-1, Wakasato, Nagano City, 380-8553 (Japan)

    2009-05-15

    The effects of a polymer additive on the supercooling of water were investigated experimentally. Poly-vinyl alcohols (PVAs) were used as the additives, and samples were prepared by dissolving the PVA in water. Since the characteristics of PVA are decided by its degrees of polymerization and saponification, these were varied along with the concentration as the experimental parameters. Moreover, the effect of purity of the water was also considered. Each sample was cooled and the temperature at the instant when ice appeared was measured. Since the freezing of supercooled water is a statistical phenomenon, many experiments were carried out and the average degree of supercooling was obtained. It was found that PVA affects the nucleation of ice in supercooled water and the degree of supercooling increases with the addition of PVA even for water with low purity. The average degree of supercooling increases with an increase in the degree of saponification of PVA. (author)

  11. Tuning optical and three photon absorption properties in graphene oxide-polyvinyl alcohol free standing films

    Energy Technology Data Exchange (ETDEWEB)

    Karthikeyan, B., E-mail: bkarthik@nitt.edu; Hariharan, S. [Department of Physics, National Institute of Technology, Tiruchirappalli 620 015 (India); Udayabhaskar, R. [Department of Physics, National Institute of Technology, Tiruchirappalli 620 015 (India); Advanced Ceramics and Nanotechnology Laboratory, Department of Materials Engineering, University of Concepcion, Concepcion 4070386 (Chile)

    2016-07-11

    We report the optical and nonlinear optical properties of graphene oxide (GO)-polyvinyl alcohol (PVA) free standing films. The composite polymer films were prepared in ex-situ method. The variation in optical absorption spectra and optical constants with the amount of GO loading was noteworthy from the optical absorption spectroscopic studies. Nonlinear optical studies done at 532 nm using 5 ns laser pulses show three photon absorption like behaviour. Both steady state and time resolved fluorescence studies reveal that the GO was functioning as a pathway for the decay of fluorescence from PVA. This is attributed to the energy level modifications of GO through hydroxyl groups with PVA. Raman spectroscopy also supports the interaction between GO and PVA ions through OH radicals.

  12. The use of polyvinyl alcohol glutaraldehyde as solid-phase in ELISA for plague

    Directory of Open Access Journals (Sweden)

    Aureci Maria Araujo

    1996-04-01

    Full Text Available Discs of polyvinyl alcohol cross-linked with glutaraldehyde were synthesized under acid catalysis (H2SO4. Then, the antigen F1 purified from Yersinia pestis was covalently linked to this modified polymer. Afterwards, an enzyme-linked immunosorbent assay (ELISA was established for the diagnosis of plague in rabbit and human. The best conditions for the method were achieved by using 1.3 ¼g of F1 prepared in 0.067 M phosphate buffer, pH 7.2, containing 1 M NaCl (PBS; anti-IgG peroxidase conjugate diluted 6,000 times and as a blocking agent 3% w/v skim milk in PBS. The titration of positive rabbit serum according to this procedure detected antibody concentrations up to 1:12,800 times. The present method, the conventional ELISA and passive haemagglutination assay are compared.

  13. Voltage Effect in Holograms of Polyvinyl Alcohol with FeCl3

    Directory of Open Access Journals (Sweden)

    Arturo Olivares-Pérez

    2014-03-01

    Full Text Available We show experimentally that the metallic salt, FeCl3, at different concentrations, provides photosensitivity and conductivity characteristics with poly(vinyl alcohol material. The holographic recording in this photosensitive material was made in real time. The effect of applied voltage on holographic diffraction gratings in the recording process and the changes in their diffraction efficiency, depending on their composition, are shown. In addition, we describe the photo-mechanism, physicochemical processes, and water condensations involved in changes of the formation of images due to applied voltage. The results suggest that polymers doped with metallic salts may have potential as inexpensive photosensitive materials that are easy to work under normal laboratory condition.

  14. Poly(vinyl chloride-grafted multi-walled carbon nanotubes via Friedel-Crafts alkylation

    Directory of Open Access Journals (Sweden)

    2010-11-01

    Full Text Available A novel approach was developed for the surface modification of the multi-walled carbon nanotubes (MWCNTs with high percentage of grafting (PG% by the grafting of polymer via the Friedel-Crafts alkylation. The graft reaction conditions, such as the amount of catalyst added, the reaction temperature, and the reaction time were optimized for the Friedel-Crafts alkylation of the MWCNTs with poly(vinyl chloride (PVC with anhydrous aluminum chloride (AlCl3 as catalyst in chloroform (CHCl3. The Fourier Transform Infrared (FT-IR, Raman, and thermogravimetric (TGA analysis showed that PVC had been successfully grafted onto MWCNTs both at the ends and on the sidewalls by the proposed Friedel-Crafts alkylation. The PVC grafted MWCNTs (PVC-MWCNTs could be dispersed well in organic solvent and the dispersion was more stable.

  15. Effects of sterilization on Poly(Vinyl Alcohol) (PVAl) hydrogels matrices

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Maria Jose A.; Rodrigues, Kiriaki M.S.; Parra, Duclerc F.; Lugao, Ademar B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], E-mail: mariajhho@yahoo.com.br

    2007-07-01

    The poly(vinyl alcohol) (PVAl) is a polymer of great interest for new materials development due to its specific characteristics particularly for biomedical applications. PVAl with polyethylene glycol (PEG) 300 was processed using freezing-thawing sequence of thermal cycles for hydrogel preparation. The samples were evaluated by gel fraction (%), water uptake (%) and thermogravimetry analysis (TGA). The hydrogel was sterilized under ionizing radiation from Cobalt-60 source at 25 kGy dose and the effects of the radiation on the hydrogel properties was discussed in this work. The results of swelling, gel fraction and thermal stability are in part influenced by the sterilization method. The presence of PEG in PVAl hydrogels forms less dense hydrogels under freeze/thawing cycles. The swelling in the sterilized hydrogels is higher than the not sterilized hydrogel in consequence of chain scissions in the polymeric structure due to the radiation process. (author)

  16. Investigations on electrostatic dissipative materials derived from Poly(vinyl alcohol/ferrofluid composites

    Directory of Open Access Journals (Sweden)

    Winatthakan Phuchaduek

    2013-10-01

    Full Text Available Biodegradable polymer composites based on polyvinyl alcohol (PVA and ferrofluid (FF were prepared by solutioncasting method. Such composites were characterized by various methods in order to evaluate their potential for use as elec-trostatic dissipative (ESD materials. Effects of ferrofluid content on mechanical, thermal, and electrical properties of thecomposites were investigated. The morphology of the composites was examined by SEM and the water contact angle on thecomposite surface was also measured. Experimental results showed that surface resistivity of the composites can be reducedby the addition of FF. The abrupt transition of such resistivity occurred in the concentration range 20-30 wt.% FF. Theconductive mechanism of the proposed composites is a complex manner, including contact conduction and tunnelingconduction.

  17. Antibacterial surfaces by adsorptive binding of polyvinyl-sulphonate-stabilized silver nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Vasilev, Krasimir; Sah, Vasu R; Goreham, Renee V; Short, Robert D [Mawson Institute, University of South Australia, Mawson Lakes Campus, Mawson Lakes, Adelaide, SA 5095 (Australia); Ndi, Chi; Griesser, Hans J, E-mail: Krasimir.vasilev@unisa.edu.au [Ian Wark Research Institute, University of South Australia, Mawson Lakes, Adelaide, SA 5095 (Australia)

    2010-05-28

    This paper presents a novel and facile method for the generation of efficient antibacterial coatings which can be applied to practically any type of substrate. Silver nanoparticles were stabilized with an adsorbed surface layer of polyvinyl sulphonate (PVS). This steric layer provided excellent colloidal stability, preventing aggregation over periods of months. PVS-coated silver nanoparticles were bound onto amine-containing surfaces, here produced by deposition of an allylamine plasma polymer thin film onto various substrates. SEM imaging showed no aggregation upon surface binding of the nanoparticles; they were well dispersed on amine surfaces. Such nanoparticle-coated surfaces were found to be effective in preventing attachment of Staphylococcus epidermidis bacteria and also in preventing biofilm formation. Combined with the ability of plasma polymerization to apply the thin polymeric binding layer onto a wide range of materials, this method appears promising for the fabrication of a wide range of infection-resistant biomedical devices.

  18. 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.

  19. Novel thermally stable poly(vinyl chloride) composites for sulfate removal

    Energy Technology Data Exchange (ETDEWEB)

    Nadagouda, Mallikarjuna N., E-mail: Nadagouda.mallikarjuna@epa.gov [Water Supply and Water Resources Division, National Risk Management Research Laboratory U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive Cincinnati, Ohio 45268 (United States); Pressman, Jonathan; White, Colin; Speth, Thomas F.; McCurry, Daniel L. [Water Supply and Water Resources Division, National Risk Management Research Laboratory U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive Cincinnati, Ohio 45268 (United States)

    2011-04-15

    Graphical abstract: Barium carbonate and/or barium carbonate-loaded silica aero-gels dispersed polyvinyl chloride (PVC) composites were prepared by dissolving PVC in tetrahydrofuran (THF), dispersing BaCO{sub 3} and/or BaCO{sub 3}-loaded silica aero-gels, re-precipitating the PVC with water at room temperature. The PVC composites were then characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray mapping, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and inductively coupled plasma mass spectrometry (ICP-MS) analysis. The obtained composites had better thermal properties than the control PVC. The composites were tested for sulfate removal and found to significantly reduce sulfate when compared with control PVC. - Abstract: BaCO{sub 3} dispersed PVC composites were prepared through a polymer re-precipitation method. The composites were tested for sulfate removal using rapid small scale column test (RSSCT) and found to significantly reduce sulfate concentration. The method was extended to synthesize barium carbonate-loaded silica aero-gels-polyvinyl chloride (PVC) polymer composites. The PVC composites were characterized using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray mapping, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and inductively coupled plasma mass spectrometry (ICP-MS) analysis. The method has advantages over conventional sulfate precipitation (sulfate removal process) using BaCO{sub 3} wherein clogging of the filter can be avoided. The method is environmentally friendly and does not interfere with natural organic matter as the conventional resin does. Some of the composites were thermally more stable as compared with the pure PVC discussed in the literature.

  20. Properties and Applications of Polyvinyl Alcohol, Halloysite Nanotubes and Their Nanocomposites

    Directory of Open Access Journals (Sweden)

    Tayser Sumer Gaaz

    2015-12-01

    Full Text Available The aim of this review was to analyze/investigate the synthesis, properties, and applications of polyvinyl alcohol–halloysite nanotubes (PVA–HNT, and their nanocomposites. Different polymers with versatile properties are attractive because of their introduction and potential uses in many fields. Synthetic polymers, such as PVA, natural polymers like alginate, starch, chitosan, or any material with these components have prominent status as important and degradable materials with biocompatibility properties. These materials have been developed in the 1980s and are remarkable because of their recyclability and consideration of the natural continuation of their physical and chemical properties. The fabrication of PVA–HNT nanocomposites can be a potential way to address some of PVA’s limitations. Such nanocomposites have excellent mechanical properties and thermal stability. PVA–HNT nanocomposites have been reported earlier, but without proper HNT individualization and PVA modifications. The properties of PVA–HNT for medicinal and biomedical use are attracting an increasing amount of attention for medical applications, such as wound dressings, drug delivery, targeted-tissue transportation systems, and soft biomaterial implants. The demand for alternative polymeric medical devices has also increased substantially around the world. This paper reviews individualized HNT addition along with crosslinking of PVA for various biomedical applications that have been previously reported in literature, thereby showing the attainability, modification of characteristics, and goals underlying the blending process with PVA.

  1. Gamma irradiation induced in situ synthesis of lead sulfide nanoparticles in poly(vinyl alcohol) hydrogel

    Science.gov (United States)

    Kuljanin-Jakovljević, Jadranka Ž.; Radosavljević, Aleksandra N.; Spasojević, Jelena P.; Carević, Milica V.; Mitrić, Miodrag N.; Kačarević-Popović, Zorica M.

    2017-01-01

    In this study, the nanocomposites based on semiconductor lead sulfide (PbS) nanoparticles and poly(vinyl alcohol) (PVA) were investigated. The gamma irradiation induced in situ incorporation of PbS nanoparticles in crosslinked polymer network i.e. PVA hydrogel was performed. PVA hydrogel was previously obtained also under the influence of gamma irradiation. UV-Vis absorption and X-ray diffraction measurements were employed to investigate optical and structural properties of PbS nanoparticles, respectively, and obtained results indicates the presence of nanoparticles with approximately 6 nm in diameter and face centered cubic rock-salt crystal structure. The porous morphology was confirmed by scanning electron microscopy. Swelling data revealed that investigated hydrogels (PVA and PbS-PVA nanocomposite) shows non-Fickian diffusion, indicating that both diffusion and polymer relaxation processes controlled the fluid transport. The values of diffusion coefficients have an order of magnitude 10-9 cm2/s (typical values for water diffusion in polymers) and the best fit with the experimental results showed the Etters approximation. Comparing the thermal properties of PbS-PVA xerogel nanocomposite with PVA xerogel it was observed that incorporation of PbS nanoparticles in crosslinked PVA matrix just slightly enhanced the thermal stability of nanocomposite.

  2. Chemically Modified Polyvinyl Chloride for Removal of Thionine Dye (Lauth’s Violet

    Directory of Open Access Journals (Sweden)

    Helena Ma A. M. M. S. Ali

    2017-11-01

    Full Text Available The chemical modification of hydrophobic polymer matrices is an alternative way to elchange their surface properties. The introduction of sulfonic groups in the polymer changes the surface properties such as adhesion, wettability, catalytic ability, and adsorption capacity. This work describes the production and application of chemically modified polyvinyl chloride (PVC as adsorbent for dyes removal. Chemical modification of PVC was evaluated by infrared spectroscopy and elemental analysis, which indicated the presence of sulfonic groups on PVC. The chemically modified PVC (PVCDS showed an ion exchange capacity of 1.03 mmol−1, and efficiently removed the thionine dye (Lauth’s violet from aqueous solutions, reaching equilibrium in 30 min. The adsorption kinetics was better adjusted for a pseudo second order model. This result indicates that the adsorption of thionine onto PVCDS occurs by chemisorption. Among the models for the state of equilibrium, SIPS and Langmuir exhibited the best fit to the experimental results and PVCDS showed high adsorption capacities (370 mg−1. Thus, it is assumed that the system presents homogeneous characteristics to the distribution of active sites. The modification promoted the formation of surface characteristics favorable to the dye adsorption by the polymer.

  3. Properties and Applications of Polyvinyl Alcohol, Halloysite Nanotubes and Their Nanocomposites.

    Science.gov (United States)

    Gaaz, Tayser Sumer; Sulong, Abu Bakar; Akhtar, Majid Niaz; Kadhum, Abdul Amir H; Mohamad, Abu Bakar; Al-Amiery, Ahmed A

    2015-12-19

    The aim of this review was to analyze/investigate the synthesis, properties, and applications of polyvinyl alcohol-halloysite nanotubes (PVA-HNT), and their nanocomposites. Different polymers with versatile properties are attractive because of their introduction and potential uses in many fields. Synthetic polymers, such as PVA, natural polymers like alginate, starch, chitosan, or any material with these components have prominent status as important and degradable materials with biocompatibility properties. These materials have been developed in the 1980s and are remarkable because of their recyclability and consideration of the natural continuation of their physical and chemical properties. The fabrication of PVA-HNT nanocomposites can be a potential way to address some of PVA's limitations. Such nanocomposites have excellent mechanical properties and thermal stability. PVA-HNT nanocomposites have been reported earlier, but without proper HNT individualization and PVA modifications. The properties of PVA-HNT for medicinal and biomedical use are attracting an increasing amount of attention for medical applications, such as wound dressings, drug delivery, targeted-tissue transportation systems, and soft biomaterial implants. The demand for alternative polymeric medical devices has also increased substantially around the world. This paper reviews individualized HNT addition along with crosslinking of PVA for various biomedical applications that have been previously reported in literature, thereby showing the attainability, modification of characteristics, and goals underlying the blending process with PVA.

  4. Photochromic properties of the N-Salicylideneaniline in Polyvinyl Butyral matrix: Experimental and theoretical investigations

    Science.gov (United States)

    Shahab, Siyamak; Filippovich, Liudmila; Aharodnikova, M.; Almodarresiyeh, Hora A.; Hajikolaee, Fatemeh Haji; Kumar, Rakesh; Mashayekhi, Mahsa

    2017-04-01

    In the present work, isomerization, photophysical properties, thermal conductivity (λ) and spectral study of the N-Salicylideneaniline: 2-[(E)-(phenylimino)methyl]phenol (SA) under the action of UV radiation in the Polyvinyl Butyral (PVB) matrix were studied using the Indicator method and Density Functional Theory (DFT). The electronic absorption spectra of SA and its isomers (SA1 and SA2) in dimethylformamide (DMF) solutions were also calculated. The nature of absorption bands of SA, SA1 and SA2 in the visible and near ultraviolet spectral regions was interpreted. The excitation energies, electronic transitions and oscillator strengths for SA, SA1 and SA2 have also been calculated. Thermal Conductivity of PVB-films containing SA before and after UV radiation was also measured. A Photochromic PVB - film on the basis of SA for application in optical devices and display technologies was made.

  5. Evaluation of cementitious repair mortars modified with polymers

    Directory of Open Access Journals (Sweden)

    Tsai-Lung Weng

    2017-01-01

    Full Text Available The aim of this study was to evaluate the effects of added polymers on the properties of repair mortars. Two types of polymers, ethylene vinyl acetate and polyvinyl acetate–vinyl carboxylate, were used as a replacement for 3%, 5%, and 8% of the cement (by weight. All tests were conducted using two water–cement ratios of 0.5 and 0.6. The effectiveness of the repair materials was evaluated according to setting time, drying shrinkage, thermal expansion, compressive strength, and bond strength. Specimens containing polyvinyl acetate–vinyl carboxylate at a water–cement ratio of 0.5 presented the highest compressive and bond strength. Specimens containing ethylene vinyl acetate presented strength characteristics exceeding those of the control at 28 days. The drying shrinkage of polyvinyl acetate–vinyl carboxylate specimens was similar to that of the control. At a water–cement ratio of 0.5, the thermal expansion of polyvinyl acetate–vinyl carboxylate specimens was lower than that of ethylene vinyl acetate specimens; however, at a water–cement ratio of 0.6, the thermal expansion was independent of the type of polymer.

  6. One-Step Dipping Method for Covalently Grafting Polymer Films onto a Si Surface from Aqueous Media.

    Science.gov (United States)

    Zhang, Junhong; Li, Ming; Zhang, Wenqi; Cao, Liqiang

    2016-08-30

    A facile and one-pot dipping method was proposed in this article for the first time to prepare vinylic polymer films on a silicon (Si) surface. This novel process was conducted in acidic aqueous media containing 4-nitrobenzene diazonium (NBD) tetrafluoroborate, hydrofluoric acid (HF), and vinylic monomers at room temperature in the open air and without any apparatus requirement. The formation of the polyvinyl film was confirmed by corroborating evidence from ellipsometry, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and atomic force microscope (AFM) analysis. The results revealed that both polymers of poorly water soluble methyl methacrylate (MMA) and water-soluble acrylic acid (AA) monomers were covalently grafted onto the Si surface via this simple process. The polyvinyl film was composed of polynitrophenyl (PNP) and polyvinyl, where PNP was doped into polyvinyl chains throughout the entire film. From a mechanistic point of view, the simple dipping method took advantage of the ability of the NBD cation to be spontaneously reduced at the Si surface at open circuit potential, providing aryl radicals. These radicals can be covalently bonded to the Si surface to form the PNP primer layer. Although the PNP sublayer was thinner and difficult to detect, it was necessary to graft polyvinyl chains. Furthermore, the aryl radicals were used to initiate the polymerization of vinylic monomers. The radical-terminated polyvinyl chains formed in the solution were then added to the aromatic rings of the primer layer to form the expected polyvinyl film.

  7. Photodegradation of polymers physical characteristics and applications

    CERN Document Server

    Rabek, Jan F

    1996-01-01

    In this book on physical characteristics and practical aspects of polymer photodegradation Rabek emphasizes the experimental work on the subject. The most important feature of the book is the physical interpretation of polymer degradation, e.g. mechanism of UV/light absorption, formation of excited states, energy transfer mechanism, kinetics, dependence on physical properties of macromolecules and polymer matrices, formation of mechanical defects, practics during environmental ageing. He includes also some aspects of polymer photodegradation in environmental and space condition.

  8. Polarization, excited states, trans-cis properties and anisotropy of thermal and electrical conductivity of the 4-(phenyldiazenyl)aniline in PVA matrix

    Science.gov (United States)

    Shahab, Siyamak; Filippovich, Liudmila; Sheikhi, Masoome; Kumar, Rakesh; Dikusar, Evgenij; Yahyaei, Hooriye; Muravsky, Alexander

    2017-08-01

    In the present work, Polarization, Excited States, Trans-Cis (E → Z) Isomerization Properties and Anisotropy of Thermal and Electrical Conductivity of the 4-(phenyldiazenyl)aniline in the presence of polyvinyl alcohol (PVA) matrix were studied. DFT, UV/Vis, IR-Spectroscopies and Indicator Method were used for Determination of Thermal Conductivity of polymer films. The absorption spectra of the 4-(phenyldiazenyl)aniline in dimethylformamide (DMF) solvent and in aqueous medium were calculated. The nature of absorption peaks of the 4-(phenyldiazenyl)aniline in the UV/Vis spectral regions were interpreted. The solvent effect on the absorption spectrum of the 4-(phenyldiazenyl)aniline has established. The molecular HOMO-LUMO, excitation energies and oscillator strengths for E and Z isomers of the 4-(phenyldiazenyl)aniline have also been calculated and presented. Optical Properties of the PVA-films containing 4-(phenyldiazenyl)aniline have been also investigated. Polarizing Efficiency (PE) of obtained PVA-film is 98-99% at Stretching Degree (Rs) 3.5. Anisotropy of thermal and electrical conductivity of PVA-films containing E and Z isomers of the 4-(phenyldiazenyl)aniline was also measured and discussed.

  9. Research on morphologies of polyvinyl alcohol/milk nanofibers

    Directory of Open Access Journals (Sweden)

    Zhang Yan

    2016-01-01

    Full Text Available In this paper, the surface morphologies of polyvinyl alcohol/milk nanofibers produced via electrospinning technique were investigated. The electrospinning process was performed at various processing parameters (flow rate, applied voltage and different polyvinyl acetate to milk ratios (100/0, 90/10, 80/20, 70/30, and 60/40. The scanning electron microscopy and Image J software were used to characterize the surface morphologies, especially the diameter distribution of electro spun nanofibers. The results of scanning electron microscopy show that the diameter of polyvinyl acetate/milk nanofibers increases with the increase of the spinning speed and spinning voltage but decreases with the increase of the weight percentage of milk in the spinning solution. The potential applications of this bicomponent nanofibers are numerous and diverse. The research results in present paper can contribute to better control of the electrospinning process and thus expanding the applicabilities, such as dressings for wound healing in sports.

  10. Cellulose nanofibers reinforced sodium alginate-polyvinyl alcohol hydrogels: Core-shell structure formation and property characterization.

    Science.gov (United States)

    Yue, Yiying; Han, Jingquan; Han, Guangping; French, Alfred D; Qi, Yadong; Wu, Qinglin

    2016-08-20

    Core-shell structured hydrogels consisting of a flexible interpenetrating polymer network (IPN) core and a rigid semi-IPN shell were prepared through chemical crosslinking of polyvinyl alcohol (PVA) and sodium alginate (SA) with Ca(2+) and glutaraldehyde. Short cellulose nanofibers (CNFs) extracted from energycane bagasse were incorporated in the hydrogel. The shell was micro-porous and the core was macro-porous. The hydrogels could be used in multiple adsorption-desorption cycles for dyes, and the maximum methyl blue adsorption capacity had a 10% increase after incorporating CNFs. The homogeneous distribution of CNFs in PVA-SA matrix generated additional hydrogen bonds among the polymer molecular chains, resulting in enhanced density, viscoelasticity, and mechanical strength for the hydrogel. Specifically, the compressive strength of the hydrogel reached 79.5kPa, 3.2 times higher than that of the neat hydrogel. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Acrylonitrile-grafted poly(vinyl alcohol) copolymer as effective binder for high-voltage spinel positive electrode

    Science.gov (United States)

    Tanaka, Shinichi; Narutomi, Takuya; Suzuki, Shigeru; Nakao, Aiko; Oji, Hiroshi; Yabuuchi, Naoaki

    2017-08-01

    Acrylonitrile-grafted poly(vinyl alcohol) copolymer with a branched structure is synthesized and used as binder for a LiNi1/2Mn3/2O4 composite electrode. Electrode performances of composite electrodes with different binders are compared in Li cells at 50 °C. The branched copolymer has better coatability to active materials in comparison to a simple mixture of linear polymers and conventional PVdF as evidenced by hard X-ray photoelectron spectroscopy. Cyclability is effectively improved by using the branched copolymer at elevated temperatures because of high chemical stability of the coated polymer layer and formation of a protective layer on cycles. Moreover, excellent rate-capability is realized by applying the branched copolymer with high adhesive strength, and the composite electrode delivers 70 mAh g-1 of discharge capacity at a rate of 1280 mA g-1.

  12. Comparison of the Poly(vinyl alcohol Adsorption Behaviour on the Mixed Oxides with Different Surface Structure

    Directory of Open Access Journals (Sweden)

    Małgorzata WIŚNIEWSKA

    2016-05-01

    Full Text Available The adsorption and electrokinetic properties, as well as the stability of the mixed oxide suspensions in the absence and presence of poly(vinyl alcohol – PVA were studied. Two alumina-silica-titania (AST oxides were used: AST50 (TiO2 : 50 %, SiO2 : 28 %, Al2O3 : 22 % and AST71 (TiO2 : 71 %, SiO2 : 8 %, Al2O3 : 21 %. All measurements were carried out in the pH range 3 – 9 as a function of the polymer molecular weight (72 000 and 100 000 Da and degree of PVA hydrolysis (86 % and 98 %. The obtained results indicated that the PVA adsorption strongly depends on the solution pH – for AST50 it decreases and for AST71 increases with the pH rise. This is caused by various PVA chains conformation on the solid surfaces with different structures. The adsorption of poly(vinyl alcohol influences on the stability of the mixed oxides suspension. The greatest effects were observed in the presence of PVA 100 000 at pH 3 for AST50 suspension and at pH 9 for AST71 system. In these cases, polymer addition leads to significant improvement of stability conditions of examined systems.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.7778

  13. Efficient etching-free transfer of high quality, large-area CVD grown graphene onto polyvinyl alcohol films

    Energy Technology Data Exchange (ETDEWEB)

    Marta, Bogdan; Leordean, Cosmin [Babes-Bolyai University, Interdisciplinary Research Institute in Bio-Nano-Sciences, Nanobiophotonics and Laser Microspectroscopy Center, Treboniu Laurian Str. 42, Cluj-Napoca 400271 (Romania); Istvan, Todor [Babes-Bolyai University, Faculty of Physics, Biomolecular Physics Department, M Kogalniceanu Str. 1, Cluj-Napoca 400084 (Romania); Botiz, Ioan [Babes-Bolyai University, Interdisciplinary Research Institute in Bio-Nano-Sciences, Nanobiophotonics and Laser Microspectroscopy Center, Treboniu Laurian Str. 42, Cluj-Napoca 400271 (Romania); Astilean, Simion, E-mail: simion.astilean@phys.ubbcluj.ro [Babes-Bolyai University, Interdisciplinary Research Institute in Bio-Nano-Sciences, Nanobiophotonics and Laser Microspectroscopy Center, Treboniu Laurian Str. 42, Cluj-Napoca 400271 (Romania); Babes-Bolyai University, Faculty of Physics, Biomolecular Physics Department, M Kogalniceanu Str. 1, Cluj-Napoca 400084 (Romania)

    2016-02-15

    Graphical abstract: - Highlights: • One-step dry transfer method of CVD grown graphene onto PVA films. • Investigation of graphene quality and number of layers of the synthesized and transferred graphene. • Promising scalability and good quality of transferred graphene onto flexible transparent polymers. - Abstract: Graphene transfer is a procedure of paramount importance for the production of graphene-based electronic devices. The transfer procedure can affect the electronic properties of the transferred graphene and can be detrimental for possible applications both due to procedure induced defects which can appear and due to scalability of the method. Hence, it is important to investigate new transfer methods for graphene that are less time consuming and show great promise. In the present study we propose an efficient, etching-free transfer method that consists in applying a thin polyvinyl alcohol layer on top of the CVD grown graphene on Cu and then peeling-off the graphene onto the polyvinyl alcohol film. We investigate the quality of the transferred graphene before and after the transfer, using Raman spectroscopy and imaging as well as optical and atomic force microscopy techniques. This simple transfer method is scalable and can lead to complete transfer of graphene onto flexible and transparent polymer support films without affecting the quality of the graphene during the transfer procedure.

  14. Effect of Wrapped Carbon Nanotubes on Optical Properties, Morphology, and Thermal Stability of Electrospun Poly(vinyl alcohol Composite Nanofibers

    Directory of Open Access Journals (Sweden)

    Naoual Diouri

    2013-01-01

    Full Text Available Electrospinning was used to elaborate poly(vinyl alcohol (PVA nanofibers in the presence of embedded multiwall carbon nanotubes (MWCNTs in surfactant and polymer. MWCNTs were dispersed in aqueous solution using both sodium dodecyl sulfate (SDS as surfactant and Poly(vinyl pyrrolidone (PVP. Changing the surfactant and polymer concentration reveals that the maximum dispersion achievable is corresponding to the mass ratios MWCNTs : SDS—1 : 5 and MWCNTs : SDS : PVP—1 : 5 : 0.6 in the presence of the PVP. After the optimization of the dispersion process, the SEM image of the PVA/PVP/SDS/MWCNTs electrospun fibers presents high stability of the fibers with diameter around 224 nm. Infrared spectroscopy and thermal gravimetric analysis elucidate the type of interaction between the PVA and the coated carbon nanotube. The presence of PVP wrapped carbon nanotubes reduced slightly the onset of the degradation temperature of the electrospun nanofibers.

  15. Polyvinyl pyrrolidone-assisted synthesis of crystalline manganese vanadate microtubes

    Directory of Open Access Journals (Sweden)

    Li-Zhai Pei

    2013-02-01

    Full Text Available Manganese vanadate microtubes have been synthesized by a facile polyvinyl pyrrolidone-assisted hydrothermal route. X-ray diffraction pattern confirms that the microtubes are composed of monoclinic MnV2O6, tetragonal V2O5 and orthorhombic MnO2 phases. The outer diameter and inner diameter of the microtubes are about 300 nm-3 µm and 200 nm-1 µm, respectively. The tube wall thickness of the microtubes is about 50 nm-1 µm. The possible formation process of the manganese vanadate microtubes has been proposed as a polyvinyl pyrrolidone-assisted growth mechanism.

  16. Polyvinyl pyrrolidone-assisted synthesis of crystalline manganese vanadate microtubes

    Directory of Open Access Journals (Sweden)

    Li-Zhai Pei

    2012-01-01

    Full Text Available Manganese vanadate microtubes have been synthesized by a facile polyvinyl pyrrolidone-assisted hydrothermal route. X-ray diffraction pattern confirms that the microtubes are composed of monoclinic MnV2O6, tetragonal V2O5 and orthorhombic MnO2 phases. The outer diameter and inner diameter of the microtubes are about 300 nm-3 µm and 200 nm-1 µm, respectively. The tube wall thickness of the microtubes is about 50 nm-1 µm. The possible formation process of the manganese vanadate microtubes has been proposed as a polyvinyl pyrrolidone-assisted growth mechanism.

  17. Polyvinyl alcohol battery separator containing inert filler. [alkaline batteries

    Science.gov (United States)

    Sheibley, D. W.; Hsu, L. C.; Manzo, M. A. (Inventor)

    1981-01-01

    A cross-linked polyvinyl alcohol battery separator is disclosed. A particulate filler, inert to alkaline electrolyte of an alkaline battery, is incorporated in the separator in an amount of 1-20% by weight, based on the weight of the polyvinyl alcohol, and is dispersed throughout the product. Incorporation of the filler enhances performance and increases cycle life of alkaline batteries when compared with batteries containing a similar separator not containing filler. Suitable fillers include titanates, silicates, zirconates, aluminates, wood floor, lignin, and titania. Particle size is not greater than about 50 microns.

  18. 78 FR 20890 - Polyvinyl Alcohol From Taiwan: Preliminary Results of Antidumping Duty Administrative Review...

    Science.gov (United States)

    2013-04-08

    ... International Trade Administration Polyvinyl Alcohol From Taiwan: Preliminary Results of Antidumping Duty... the antidumping duty order on polyvinyl alcohol (PVA) from Taiwan. The period of review (POR) is... Memorandum for Preliminary Results of Antidumping Duty Administrative Review: Polyvinyl Alcohol from Taiwan...

  19. 76 FR 30604 - National Emission Standards for Hazardous Air Pollutants for Polyvinyl Chloride and Copolymers...

    Science.gov (United States)

    2011-05-26

    ... Polyvinyl Chloride and Copolymers Production AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed..., the proposed rule, National Emission Standards for Hazardous Air Pollutants for Polyvinyl Chloride and... Polyvinyl Chloride and Copolymers Production, under Docket ID No. EPA-HQ-OAR-2002-0037 (available at http...

  20. 76 FR 42613 - National Emission Standards for Hazardous Air Pollutants for Polyvinyl Chloride and Copolymers...

    Science.gov (United States)

    2011-07-19

    ... Polyvinyl Chloride and Copolymers Production; Extension of Comment Period AGENCY: Environmental Protection... for Hazardous Air Pollutants for Polyvinyl Chloride and Copolymers Production is being extended for 14... extend the public comment period for the May 20, 2011, Proposed Polyvinyl Chloride and Copolymers...

  1. 78 FR 39256 - Polyvinyl Alcohol From Taiwan: Rescission of Antidumping Duty Administrative Review; 2012-2013

    Science.gov (United States)

    2013-07-01

    ...] Polyvinyl Alcohol From Taiwan: Rescission of Antidumping Duty Administrative Review; 2012-2013 AGENCY... on polyvinyl alcohol (PVA) from Taiwan for the period March 1, 2012, through February 28, 2013. DATES... administrative review.\\3\\ \\3\\ See letter from CCPC to the Department, ``Polyvinyl Alcohol from Taiwan: Withdrawal...

  2. 75 FR 38079 - Postponement of Preliminary Determination of Antidumping Duty Investigation: Polyvinyl Alcohol...

    Science.gov (United States)

    2010-07-01

    ...: Polyvinyl Alcohol From Taiwan AGENCY: Import Administration, International Trade Administration, Department...) initiated the antidumping duty investigation on polyvinyl alcohol from Taiwan. See Initiation of Anti-Dumping Duty Investigation: Polyvinyl Alcohol From Taiwan, 69 FR 59204 (October 4, 2004). On October 22...

  3. 40 CFR 61.64 - Emission standard for polyvinyl chloride plants.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Emission standard for polyvinyl... Standard for Vinyl Chloride § 61.64 Emission standard for polyvinyl chloride plants. An owner or operator of a polyvinyl chloride plant shall comply with the requirements of this section and § 61.65. (a...

  4. 40 CFR 61.65 - Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants.

    Science.gov (United States)

    2010-07-01

    ... dichloride, vinyl chloride and polyvinyl chloride plants. 61.65 Section 61.65 Protection of Environment... dichloride, vinyl chloride and polyvinyl chloride plants. An owner or operator of an ethylene dichloride, vinyl chloride, and/or polyvinyl chloride plant shall comply with the requirements of this section. (a...

  5. Effect of Polymer Matrix on the Structure and Electric Properties of Piezoelectric Lead Zirconatetitanate/Polymer Composites

    Directory of Open Access Journals (Sweden)

    Rui Li

    2017-08-01

    Full Text Available Piezoelectric lead zirconatetitanate (PZT/polymer composites were prepared by two typical polymer matrixes using the hot-press method. The micromorphology, microstructure, dielectric properties, and piezoelectric properties of the PZT/polymer composites were characterized and investigated. The results showed that when the condition of frequency is 103 Hz, the dielectric and piezoelectric properties of PZT/poly(vinylidene fluoride were both better than that of PZT/polyvinyl chloride (PVC. When the volume fraction of PZT was 50%, PZT/PVDF prepared by the hot-press method had better comprehensive electric property.

  6. Rheology and structure of aqueous bentonite–polyvinyl alcohol ...

    Indian Academy of Sciences (India)

    (Cameron 1977; Heath and Tadros 1982; Tadros 1987;. Lagaly 1989; Güven 1992; Ece et al 1999; Luckham and. Rossi 1999; Alemdar et al 2000; Neaman and Singer. 2000). ... tate groups [–(CH2CHOH)n. &+2CHOCOCH3)m–]. Chemi- cal and physical properties of commercial polyvinyl alcohol. (PVA) varied depending ...

  7. Size variation of polyaniline nanoparticles dispersed in polyvinyl ...

    Indian Academy of Sciences (India)

    We report the preparation of polyaniline (PANI) nanoparticles dispersed in polyvinyl alcohol (PVA) matrix. From SEM picture it is seen that the particle sizes vary from 100–20 nm. Also with increase in PVA content the stability of dispersion is found to increase. Apart from SEM, spin cast films of PANI in PVA are also ...

  8. The study of epoxy polyamide and polyvinyl resins as corrosion ...

    African Journals Online (AJOL)

    The corrosion resistance of two commonly used protective coatings (epoxy polyamide and polyvinyl resins) in the Niger Delta area of Nigeria has been assessed. The coatings on low carbon steel were subjected to varying conditions of pH, temperature and exposure time and the corrosion rates calculated. At a pH of 2, 3, 4, ...

  9. Short cellulose nanofribrils as reinforcement in polyvinyl alcohol fiber

    Science.gov (United States)

    Jun Peng; Thomas Ellingham; Ron Sabo; Lih-Sheng Turng; Craig M. Clemons

    2014-01-01

    Short cellulose nanofibrils (SCNF) were investigated as reinforcement for polyvinyl alcohol (PVA) fibers. SCNF were mechanically isolated from hard wood pulp after enzymatic pretreatment. Various levels of SCNF were added to an aqueous PVA solution, which was gel-spun into continuous fibers. The molecular orientation of PVA was affected by a combination of wet drawing...

  10. Ultraviolet sensing properties of polyvinyl alcohol-coated aluminium ...

    Indian Academy of Sciences (India)

    Undoped and aluminium (Al)-doped zinc oxide (ZnO) nanorods have been synthesized by electrochemical route. The synthesized materials have been characterized by X-ray diffraction, UV–visible spectrometer and scanning electron microscope. The Al-doped ZnO nanorods have been coated with polyvinyl alcohol.

  11. Rheology and structure of aqueous bentonite–polyvinyl alcohol ...

    Indian Academy of Sciences (India)

    Keywords. Bentonite–polyvinyl alcohol dispersions; rheology; zeta potential; particle size analysis; SEM; FTIR studies. ... Ünlü2 O Atici2 N Güngör1. Department of Physics, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey; Department of Chemistry, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey ...

  12. Poly(vinyl alcohol) gels as photoacoustic breast phantoms revisited

    NARCIS (Netherlands)

    Xia, W.; Piras, D.; Heijblom, M.; Steenbergen, Wiendelt; van Leeuwen, Ton; Manohar, Srirang

    2011-01-01

    A popular phantom in photoacoustic imaging is poly(vinyl alcohol) (PVA) hydrogel fabricated by freezing and thawing (F–T) aqueous solutions of PVA. The material possesses acoustic and optical properties similar to those of tissue. Earlier work characterized PVA gels in small test specimens where

  13. Poly(vinyl alcohol) gels as photoacoustic breast phantoms revisited

    NARCIS (Netherlands)

    Xia, Wenfeng; Piras, Daniele; Heijblom, Michelle; Steenbergen, Wiendelt; van Leeuwen, Ton G.; Manohar, Srirang

    2011-01-01

    A popular phantom in photoacoustic imaging is poly(vinyl alcohol) (PVA) hydrogel fabricated by freezing and thawing (F-T) aqueous solutions of PVA. The material possesses acoustic and optical properties similar to those of tissue. Earlier work characterized PVA gels in small test specimens where

  14. Analysis of the properties of dehydrochlorinated polyvinyl chloride films

    Science.gov (United States)

    Kryshtob, V. I.; Rasmagin, S. I.

    2017-11-01

    The effect of the time of thermolysis (thermal degradation) on the absorption spectra, specific resistivity, and concentration of holes of partially dehydrochlorinated polyvinyl chloride films has been studied. The number of conjugated carbon double bonds in films has been determined as a function of the time of thermolysis.

  15. Improved chlorine tolerance of a polyvinyl pyrrolidone-polysulfone membrane enabled by carboxylated carbon nanotubes.

    Science.gov (United States)

    Xie, Pengchao; de Lannoy, Charles-François; Ma, Jun; Wang, Zongping; Wang, Songlin; Li, Jingjing; Wiesner, Mark R

    2016-11-01

    Chemical cleaning of membranes may be limited by the tolerance of some polymeric membranes to chlorine. In this work we show that modification of a polyvinyl pyrrolidone-polysulfone (PVP-PSF) membrane with carboxylated carbon nanotubes (CNTs) leads to greater chlorine tolerance of the membrane along with smoothing the surface roughness and improving some membrane properties including permeability, hydrophilicity and antifouling ability. In comparison with PVP-PSF membrane, incorporating carboxylated CNTs reduced the release of organic matter from the membrane and caused less decrease in hydrophilicity, permeability and BSA rejection. After chlorine treatment of a conventional PVP-PSF membrane, an infrared absorbance peak around 1670 cm-1, representing the vibration of the amide bond in the PVP, decreased significantly and two smaller peaks at around 1725 and 1775 cm-1 were observed. The percentage of C-Cl (2p) in the PVP-PSF membrane was about 2.8 times greater than that of the carboxylated CNT-composite PVP-PSF (CNT-PVP-PSF) membrane after chlorine exposure, suggesting greater chlorine tolerance of CNT-PVP-PSF membrane. In comparison with PVP-PSF membrane, the formation of toxic chlorinated byproducts during chlorination of organic matter released from CNT-PVP-PSF membrane was much lower. The improvement of tolerance to chlorine is attributed to stabilization of the polymer through hydrogen bonding between polymer and carboxylated CNTs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. A polyvinyl alcohol/ p-sulfonate phenolic resin composite proton conducting membrane

    Science.gov (United States)

    Wu, Chien-Shun; Lin, Fan-Yen; Chen, Chih-Yuan; Chu, Peter P.

    Membranes composed of poly(vinyl alcohol) (PVA) and a proton source polymer, sulfonated phenolic resin (s-Ph) displayed good proton conductivity of the order of 10 -2 S cm -1 at ambient temperatures. Upon cross-linking above 110 °C, covalent links between the sulfonate groups of the phenolic resin and the hydroxyl groups of the PVA were established. Although this sacrificed certain sulfonate groups, the conductivity value was still preserved at the 10 -2 S cm -1 level. In sharp contrast to Nafion, the current membrane (both before and after cross-linking) was also effective in reducing the methanol uptake where the swelling ratio decreased with increase of methanol concentration. Although both the methanol permeation and the proton conductivity were lower compared to Nafion, the conductivity/permeability ratio of 0.97 for the PVA/s-Ph is higher than that determined for Nafion. The results suggested the effectiveness of proton transport in the polymer-complex structure and the possibility that a high proton conductivity can be realized with less water.

  17. Synthesis of poly(vinyl alcohol)-magnetite ferrogel obtained by freezing-thawing technique

    Science.gov (United States)

    Reséndiz-Hernández, P. J.; Rodríguez-Fernández, O. S.; García-Cerda, L. A.

    Polymer gels are crosslinked polymer networks swollen by a fluid. If magnetic particles either as powder or dispersed in a magnetic fluid are introduced into the gel then the system becomes sensitive to external magnetic fields and the resulting material is called ferrogel. The polyvinyl alcohol (PVA)-magnetite ferrogels system has properties that are attractive for artificial muscles and drug delivery systems for biomedical applications. This work investigates the synthesis and characterization of a ferrogel obtained by freezing-thawing cycles. PVA ( MW=89,000-98,000, degree of hydrolyzation: 99 mol%) and magnetite nanoparticles (˜12 nm) obtained by chemical coprecipitation were used as raw materials. The PVA-magnetite ferrogels were prepared by subjecting a PVA/DMSO/magnetite solution (2 g/30 ml/0.2 g) to freeze (-25 °C)/thaw (+25 °C) cycles. The resulting ferrogel was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), differential scanning calorimetry (DSC) and vibration sample magnetometry (VSM). The magnetic particles inside the PVA matrix formed agglomerates with average size ˜58 nm. All the ferrogels showed superparamagnetic behavior with maximum magnetization of 0.6 emu/g.

  18. 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. ...

  19. Investigating the properties and interaction mechanism of nano-silica in polyvinyl alcohol/polyacrylamide blends at an atomic level.

    Science.gov (United States)

    Wei, Qinghua; Wang, Yanen; Wang, Shuzhi; Zhang, Yingfeng; Chen, Xiongbiao

    2017-11-01

    The nano-silica can be incorporated into polymers for improved mechanical properties. Notably, the interaction between nano-silica and polymer is of a microscopic phenomenon and thus, hard to observe and study by using experimental methods. Based on molecular dynamics, this paper presents a study on the properties and the interaction mechanism of nano-silica in the polyvinyl alcohol (PVA)/polyacrylamide (PAM) blends at an atomic level. Specifically, six blends of PVA/PAM with varying concentrations of nano-silica (0-13wt%) and two interfacial interaction models of polymers on the silica surface were designed and analyzed at an atomic level in terms of concentration profile, mechanical properties, fractional free volume (FFV), dynamic properties of polymers and X-ray diffraction patterns. The concentration profile results and micromorphologies of equilibrium models suggest PAM molecular chains are easier to be adsorbed on the silica surface than PVA molecular chains in blends. The incorporation of nano-silica into the PVA/PAM blends can increase the blend mechanical properties, densities, and semicrystalline character. Meanwhile, the FFV and the mobility of polymer chain decrease with the silica concentration, which agrees with the results of mechanical properties, densities, and semicrystalline character. Our results also illustrate that an analysis of binding energies and pair correlation functions (PCF) allows for the discovery of the interaction mechanism of nano-silica in PVA/PAM blends; and that hydrogen bond interactions between polar functional groups of polymer molecular chains and the hydroxyl groups of the silica surface are involved in adsorption of the polymers on the silica surface, thus affecting the interaction mechanism of nano-silica in PVA/PAM blend systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Orientational photorefractive properties in polymer-dispersed liquid crystals with different polymer matrixes

    Science.gov (United States)

    Ono, Hiroshi; Saito, Isao; Kawatsuki, Nobuhiro

    1998-10-01

    We report orientational photorefractive effects observed in photoconductive liquid crystals (LCs) contained with three kinds of polymer, i.e., poly(methyl methacrylate) (PMMA), poly(vinyl alcohol) (PVA) and a side-chain liquid crystalline polymer (SLCP1). The morphology of the photorefractive composites depended on the kind of polymer strongly. In both PMMA and PVA cases, LC and polymer were phase-separated and the composite showed memory effects. In SLCP1 case, the phase-separation in the composite dose not occur and the high resolution could be achieved. In this case, the photorefractive Bragg gratings were generated and a high two-beam coupling gain coefficient with a low applied field of 4 V/micrometers was observed.

  1. Liquid Crystal Alignment Control Using Polymer Filament and Polymer Layers Coated on Substrates

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2005-04-01

    We investigated liquid crystal (LC) alignment in LC cells containing an aligned cellulose filament sandwiched by thin polymer layers coated on substrates. Three types of polymer material, namely polystyrene (PS), polyvinyl alcohol (PVA) and polyimide (PI), were used as polymer layers. LC alignment areas induced on both sides of the filament were large in the order of PS, PVA and PI. In the case of the PS layer, the average LC alignment area reached approximately 100 μm in the direction perpendicular to the polymer filament. The molecular interaction between the LC and the PS layer is thought to be weak and it does not disturb the LC alignment due to the polymer filament. On the other hand, rubbed PS layers were used as polymer layers of the LC cell, where the LC alignment direction induced by the rubbed PS layer was perpendicular to the polymer filament. It was found that the LC alignment near the polymer filament gradually bent in the cell plane. The result suggests that various three-dimensional LC alignments can be realized by the combination of the polymer filament and substrate surface.

  2. Atomistic modeling of interfacial interaction between polyvinyl chloride and polypropylene with Boron-Nitride monolayer sheet: A density functional theory study

    Science.gov (United States)

    Hamed Mashhadzadeh, A.; Fereidoon, A.; Ghorbanzadeh Ahangari, M.

    2017-11-01

    In present work, we performed Density Functional Theory calculation (DFT) to prepare polypropylene (PP) and polyvinyl chloride (PVC) nanocomposite. For mentioned purpose, we chose Boron-Nitride graphene (BN-graphene) sheet as nano reinforcement. Next, we calculated adsorbed energy between these two polymeric matrixes with BN-monolayer sheet. Our DFT results demonstrated that interaction energy between PP/BN-graphene and PVC/BN-graphene are equal, approximately, because in mentioned two nanocomposite systems, polymer matrix approached to nano reinforcement from hydrogen atom in optimized structure. Then, the adsorbed energy and equilibrium distance between mentioned polymeric matrixes and BN-graphene sheet in nanocomposite with increasing the number of polymer monomers onto surface of BN-graphene were calculated. Finally, we modeled van der Waals interfacial interaction between polymer matrixes and nano reinforcement with linear classical spring by using lennard-jones parameters.

  3. Effects of the gamma radiation on the molecular structure of the poly(vinyl alcohol); Efeitos da radiacao gama na estrutura molecular do poli(alcool vinilico)

    Energy Technology Data Exchange (ETDEWEB)

    Terence, Mauro C. [Universidade Presbiteriana Mackenzie, Sao Paulo, SP (Brazil). Dept. de Engenharia de Materiais]. E-mail: mterence@usp.br; Guedes, Selma M.L. [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes

    2002-07-01

    The poly(vinyl alcohol) (PVAL) is a polymer used as biomaterial. The PVAL was used as ocular insert and may be used as a drug delivery system for pair PVAL/dihidroxipropoxymethyl guanine, where the last one is used for treatment of people with retinite caused by cytomegalovirus. These inserts are crosslinked systems. The crosslink was induced by gamma radiation applied in polymer. The samples of PVAL was irradiated by gamma rays with doses in the range 0 to 200 kGy. On irradiated PVAL samples was observed a low yellowness, attributed to the formation of polymeric radicals that are stable in the structure of the polymer, from radiolysis of PVAL. (author)

  4. Polymer Nanocomposites

    Indian Academy of Sciences (India)

    The synthesis of polymer nanocomposites is an integral aspect of polymer nanotechnology. By inserting the nano- metric inorganic compounds, the properties of polymers improve and hence this has a lot of applications depending upon the inorganic material present in the polymers. Sol- vent casting is one of the easiest ...

  5. Ferrocene bound poly(vinyl chloride) as ion to electron transducer in electrochemical ion sensors.

    Science.gov (United States)

    Pawlak, Marcin; Grygolowicz-Pawlak, Ewa; Bakker, Eric

    2010-08-15

    We report here on the synthesis of poly(vinyl chloride) (PVC) covalently modified with ferrocene groups (FcPVC) and the electrochemical behavior of the resulting polymeric membranes in view of designing all solid state voltammetric ion sensors. The Huisgen cycloaddition ("click chemistry") was found to be a simple and efficient method for ferrocene attachment. A degree of PVC modification with ferrocene groups between 1.9 and 6.1 mol % was achieved. The chemical modification of the PVC backbone does not significantly affect the ion-selective properties (selectivity, mobility, and solvent casting ability) of potentiometric sensing membranes applying this polymer. Importantly, the presence of such ferrocene groups may eliminate the need for an additional redox-active layer between the membrane and the inner electric contact in all solid state sensor designs. Electrochemical doping of this system was studied in a symmetrical sandwich configuration: glassy carbon electrode |FcPVC| glassy carbon electrode. Prior electrochemical doping from aqueous solution, resulting in a partial oxidation of the ferrocene groups, was confirmed to be necessary for the sandwich configuration to pass current effectively. The results suggest that only approximately 2.3 mol % of the ferrocene groups are electrochemically accessible, likely due to surface confined electrochemical behavior in the polymer. Indeed, cyclic voltammetry of aqueous hexacyanoferrate (III) remains featureless at cathodic potentials (down to -0.5 V). This indicates that the modified membrane is not responsive to redox-active species in the sample solution, making it possible to apply this polymer as a traditional, single membrane. Yet, the redox capacity of the electrode modified with this type of membrane was more than 520 microC considering a 20 mm(2) active electrode area, which appears to be sufficient for numerous practical ion voltammetric applications. The electrode was observed to operate reproducibly, with 1

  6. 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.

  7. 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

  8. Comparison of the performances of four hydrophilic polymers as supports for lipase immobilisation

    OpenAIRE

    Toscano, Lydia; Montero, Gisela; Stoytcheva, Margarita; Cervantes, Lourdes; Gochev, Velizar

    2014-01-01

    Four hydrophilic polymers in the form of beads ? chitosan, alginate, alginate/polyvinyl alcohol (PVA), and chitosan-coated alginate ? were used as supports for lipase immobilisation. Hydrogel beads were characterised by bead-size-distribution estimation, surface morphology studies, and polymer interactions assessment. Matrix performances ? loading efficiency, immobilisation yield, enzyme activity, and stability retention ? were evaluated and compared. Although the loading efficiency of the ch...

  9. Poly(vinyl methyl ether) hydrogels at temperatures below the freezing point of water-molecular interactions and states of water.

    Science.gov (United States)

    Pastorczak, Marcin; Dominguez-Espinosa, Gustavo; Okrasa, Lidia; Pyda, Marek; Kozanecki, Marcin; Kadlubowski, Slawomir; Rosiak, Janusz M; Ulanski, Jacek

    2014-01-01

    Water interacting with a polymer reveals a number of properties very different to bulk water. These interactions lead to the redistribution of hydrogen bonds in water. It results in modification of thermodynamic properties of water and the molecular dynamics of water. That kind of water is particularly well observable at temperatures below the freezing point of water, when the bulk water crystallizes. In this work, we determine the amount of water bound to the polymer and of the so-called pre-melting water in poly(vinyl methyl ether) hydrogels with the use of Raman spectroscopy, dielectric spectroscopy, and calorimetry. This analysis allows us to compare various physical properties of the bulk and the pre-melting water. We also postulate the molecular mechanism responsible for the pre-melting of part of water in poly(vinyl methyl ether) hydrogels. We suggest that above -60 °C, the first segmental motions of the polymer chain are activated, which trigger the process of the pre-melting.

  10. Post-electrospinning crosslinking of guar/polyvinyl alcohol membrane

    Directory of Open Access Journals (Sweden)

    Shi Jingjing

    2016-01-01

    Full Text Available College of Material and Textile Engineering, Jiaxing University, Jiaxing, China The present study reports post-electrospinning crosslinking of guar/polyvinyl alcohol (PVA/citric acid nanofiber membranes by heat treatment. Porous, interconnected nonwoven nanofiber membranes (average diameter 194±23 nm were electrospun from a homogeneous blend of 1wt% guar gum and 8wt% polyvinyl alcohol solution (3:7 weight ratio containing 5 wt% (by the total weight of the solution citric acid. The electrospun nanofiber membranes were then cured at 140 oC for 2 h. The crosslinked nanofiber membranes were insoluble in water, while the non-crosslinked membranes dissolved instantaneously. FT-IR spectrum investigates that crosslinking of guar/PVA occurred through esterfication reaction during heat treatment.

  11. Multiple High Voltage Pulse Stressing of Polymer Thick Film Resistors

    Directory of Open Access Journals (Sweden)

    Busi Rambabu

    2014-01-01

    Full Text Available The purpose of this paper is to study high voltage interactions in polymer thick film resistors, namely, polyvinyl chloride- (PVC- graphite thick film resistors, and their applications in universal trimming of these resistors. High voltages in the form of impulses for various pulse durations and with different amplitudes have been applied to polymer thick film resistors and we observed the variation of resistance of these resistors with high voltages. It has been found that the resistance of polymer thick film resistors decreases in the case of higher resistivity materials and the resistance of polymer thick film resistor increases in the case of lower resistivity materials when high voltage impulses are applied to them. It has been also found that multiple high voltage pulse (MHVP stressing can be used to trim the polymer thick film resistors either upwards or downwards.

  12. Poly(vinyl alcohol) acetoacetate-based tissue adhesives are non-cytotoxic and non-inflammatory.

    Science.gov (United States)

    Bhatia, Sujata K; Arthur, Samuel D

    2008-08-01

    Polymer-based tissue adhesives composed of poly(vinyl alcohol) acetoacetate (PVOH acac) and cross-linking amines were investigated for their effects on cell survival and inflammatory cell activation using in vitro mouse cell cultures. Cytotoxicity of tissue adhesives was evaluated by placing adhesives in direct contact with 3T3 fibroblast cells. Tissue adhesives formulated from PVOH acac and 3-aminopropyltrialkoxysilane (APS) were non-cytotoxic to fibroblasts; adhesives formulated from PVOH acac and aminated poly(vinyl alcohol) (PVOH amine) were also non-cytotoxic to fibroblasts. In contrast, a commercial adhesive composed of 2-octyl cyanoacrylate was highly cytotoxic to fibroblasts. The inflammatory potential of tissue adhesives was evaluated by exposing J774 macrophage cells to adhesives, and measuring TNF-alpha release from macrophages. PVOH acac-based tissue adhesives did not elicit inflammatory TNF-alpha release from macrophages. These results suggest that PVOH acac-based tissue adhesives are non-cytotoxic and non-inflammatory. Such tissue adhesives represent a promising technology for a variety of medical applications, including surgical wound closure and tissue engineering, and the results are also significant in the design of in vitro cell culture systems to study biomaterials.

  13. Studies of Degradation of Plasticized Polyvinyl Chloride (PPVC)

    OpenAIRE

    Doina Elena Gavrilă

    2016-01-01

    Commercial plasticizers are introduced in Polyvinyl Chloride (PVC) to obtain flexibility, high elongation to break, durability, resistance to heat and chemicals. Very used plasticizers are phthalates, most commonly phthalate being di-2-ethyl hexyl phthalate (DEHP). The phthalates are not chemically bound to PVC and can migrate from different devices and objects due to the influence of temperature, or to other types of degradation. In article are presented the harm effects of phtha...

  14. Lost bits: particle shedding with polyvinyl chloride intravenous administration sets.

    Science.gov (United States)

    Subramanian, Peter; Ainsworth, Paul; Cassey, John; Phelan, David

    2002-12-01

    Silicone particles have been demonstrated in the effluent from silicone intravenous (IV) tubing. It has been widely suspected that polyvinyl chloride (PVC) particles are also lost. We sought to clarify the situation in a carefully controlled laboratory setting using the apparatus and flow rates common in a paediatric setting, using scanning electron microscope techniques (SEM), we found that particles were indeed shed from IV tubing during use, but they were not PVC.

  15. Production and Characterization of 3-Methacryloxypropyltrimethoxysilane Modified Polyvinyl Acetate Dispersion

    Directory of Open Access Journals (Sweden)

    Mindaugas Dubininkas

    2016-03-01

    Full Text Available Semi-continuous vinyl acetate (VAc radical emulsion polymerization in water with 3-methacryloxypropyltrimethoxysilane (GF31 co-monomer was performed using protective colloid PVA and surface-active compound. The impact of GF31 on polyvinyl acetate (PVAc dispersion physicochemical and production parameters were determined. Even low quantities of GF31 (up to 1.5 % of VAc mass had crucial impact on PVAc dispersion and dispersion film’s parameters.

  16. Physical Properties and Effect in a Battery of Safety Pharmacology Models for Three Structurally Distinct Enteric Polymers Employed as Spray-dried Dispersion Carriers

    Directory of Open Access Journals (Sweden)

    Ryan M Fryer

    2016-10-01

    Full Text Available Establishing a wide therapeutic index (TI for pre-clinical safety is important during lead optimization (LO in research, prior to clinical development, although is often limited by a molecules physiochemical characteristics. Recent advances in the application of the innovative vibrating mesh spray-drying technology to prepare amorphous solid dispersions may offer an opportunity to achieve high plasma concentrations of poorly soluble NCEs to enable testing and establishment of a wide TI in safety pharmacology studies. While some of the amorphous solid dispersion carriers are generally recognized as safe for clinical use, whether they are sufficiently benign to enable in vivo pharmacology studies has not been sufficiently demonstrated. Thus, the physical properties, and effect in a battery of in vivo safety pharmacology models, were assessed in three classes of polymers employed as spray-dried dispersion carriers. The polymers (HPMC-AS, Eudragit, PVAP displayed low affinity with acetone/methanol, suitable for solvent-based spray drying. The water sorption of the polymers was moderate, and the degree of hysteresis of HPMC-AS was smaller than Eudragit and PVAP indicating the intermolecular interaction of water-cellulose molecules is weaker than water-acrylate or water-polyvinyl molecules. The polymer particles were well-suspended without aggregation with a mean particle size less than 3 µm in an aqueous vehicle. When tested in conscious Wistar Han rats in safety pharmacology models (n=6-8/dose/polymer investigating effects on CNS, gastrointestinal, and cardiovascular function, no liabilities were identified at any dose tested (30-300 mg/kg PO, suspension. In brief, the polymers had no effect in a modified Irwin test that included observational and evoked endpoints related to stereotypies, excitation, sedation, pain/anesthesia, autonomic balance, reflexes, and others. No effect of the polymers on gastric emptying or intestinal transit was observed

  17. The Mediterranean Plastic Soup: synthetic polymers in Mediterranean surface waters

    Science.gov (United States)

    Suaria, Giuseppe; Avio, Carlo G.; Mineo, Annabella; Lattin, Gwendolyn L.; Magaldi, Marcello G.; Belmonte, Genuario; Moore, Charles J.; Regoli, Francesco; Aliani, Stefano

    2016-01-01

    The Mediterranean Sea has been recently proposed as one of the most impacted regions of the world with regards to microplastics, however the polymeric composition of these floating particles is still largely unknown. Here we present the results of a large-scale survey of neustonic micro- and meso-plastics floating in Mediterranean waters, providing the first extensive characterization of their chemical identity as well as detailed information on their abundance and geographical distribution. All particles >700 μm collected in our samples were identified through FT-IR analysis (n = 4050 particles), shedding for the first time light on the polymeric diversity of this emerging pollutant. Sixteen different classes of synthetic materials were identified. Low-density polymers such as polyethylene and polypropylene were the most abundant compounds, followed by polyamides, plastic-based paints, polyvinyl chloride, polystyrene and polyvinyl alcohol. Less frequent polymers included polyethylene terephthalate, polyisoprene, poly(vinyl stearate), ethylene-vinyl acetate, polyepoxide, paraffin wax and polycaprolactone, a biodegradable polyester reported for the first time floating in off-shore waters. Geographical differences in sample composition were also observed, demonstrating sub-basin scale heterogeneity in plastics distribution and likely reflecting a complex interplay between pollution sources, sinks and residence times of different polymers at sea. PMID:27876837

  18. The Mediterranean Plastic Soup: synthetic polymers in Mediterranean surface waters

    Science.gov (United States)

    Suaria, Giuseppe; Avio, Carlo G.; Mineo, Annabella; Lattin, Gwendolyn L.; Magaldi, Marcello G.; Belmonte, Genuario; Moore, Charles J.; Regoli, Francesco; Aliani, Stefano

    2016-11-01

    The Mediterranean Sea has been recently proposed as one of the most impacted regions of the world with regards to microplastics, however the polymeric composition of these floating particles is still largely unknown. Here we present the results of a large-scale survey of neustonic micro- and meso-plastics floating in Mediterranean waters, providing the first extensive characterization of their chemical identity as well as detailed information on their abundance and geographical distribution. All particles >700 μm collected in our samples were identified through FT-IR analysis (n = 4050 particles), shedding for the first time light on the polymeric diversity of this emerging pollutant. Sixteen different classes of synthetic materials were identified. Low-density polymers such as polyethylene and polypropylene were the most abundant compounds, followed by polyamides, plastic-based paints, polyvinyl chloride, polystyrene and polyvinyl alcohol. Less frequent polymers included polyethylene terephthalate, polyisoprene, poly(vinyl stearate), ethylene-vinyl acetate, polyepoxide, paraffin wax and polycaprolactone, a biodegradable polyester reported for the first time floating in off-shore waters. Geographical differences in sample composition were also observed, demonstrating sub-basin scale heterogeneity in plastics distribution and likely reflecting a complex interplay between pollution sources, sinks and residence times of different polymers at sea.

  19. Isovector monopole excitation energies

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, J.D.; Lipparini, E.; Stringary, S.

    1987-11-05

    Using a hydrodynamical model whose parameters have been adjusted to fit the polarizability and excitation energy of the giant dipole nuclear resonance we predict excitation energies of the isovector monopole resonance. The predicted values are in good agreement with experimental data. The mass dependence of the excitation energy is strongly influenced by nuclear geometry.

  20. Surface Properties of a Novel Poly(vinyl alcohol Film Prepared by Heterogeneous Saponification of Poly(vinyl acetate Film

    Directory of Open Access Journals (Sweden)

    Seong Baek Yang

    2017-10-01

    Full Text Available Almost general poly(vinyl alcohol (PVA films were prepared by the processing of a PVA solution. For the first time, a novel poly(vinyl alcohol (PVA film was prepared by the saponification of a poly(vinyl acetate (PVAc film in a heterogenous medium. Under the same saponification conditions, the influence of saponification time on the degree of saponification (DS was studied for the preparation of the saponified PVA film, and it was found that the DS varied with time. Optical microscopy was used to confirm the characteristics and surface morphology of the saponified PVA film, revealing unusual black globules in the film structure. The contact angle of the films was measured to study the surface properties, and the results showed that the saponified PVA film had a higher contact angle than the general PVA film. To confirm the transformation of the PVAc film to the PVA film, 1H nuclear magnetic resonance spectroscopy, X-ray diffraction measurements, differential scanning calorimetry, and Fourier-transform infrared spectroscopy were employed.

  1. Gum tragacanth-polyvinyl alcohol cryogel and xerogel blends for oral delivery of silymarin: Structural characterization and mucoadhesive property.

    Science.gov (United States)

    Niknia, Nushin; Kadkhodaee, Rassoul

    2017-12-01

    In this study silymarin (SM) loaded cryo- and xerogels of gum tragacanth-polyvinyl alcohol (GT-PVA) were prepared and their physico-mechanical, microstructural and release properties were investigated. The results showed that unlike cryogels, which were highly porous, xerogels exhibited a densely packed agglomerated microstructure with a continuous network of cracks. The bulk density, mechanical strength and SM retention of xerogels were also much higher than those of cryogels. Furthermore, it was revealed that increasing the ratio of GT adversely influenced both physico-mechanical and structural features of the dried gels, but improved the release profile of SM. Incorporation of SM into the gels led to a distinct enhancement in their porosity, microstructure and physical properties. Rheological measurements indicated that rising the ratio of GT and inclusion of SM increased the viscosity of mucin-polymers blend and improved mucoadhesive property of the gels. Copyright © 2017. Published by Elsevier Ltd.

  2. Synthesis of Luminescent Ink from Europium-Doped Y2O3 Dispersed in Polyvinyl Alcohol Solution

    Directory of Open Access Journals (Sweden)

    Astuti

    2009-01-01

    Full Text Available Luminescent ink from europium-doped Y2O3 ( Y2O3:Eu has been synthesized by two steps method: first, synthesis of luminescent powder of Y2O3:Eu by simple heating of metallic nitrates in a polymer solution and second, dispersing the powder in a polyvinyl alcohol (PVA solution. The stability of the ink (luminescent colloid was strongly affected by mixing process of the powder and the solution. Mixing process must be performed for a long time (about 8 hours at above room temperature to product stable colloids. We observed that mixing at 30–40∘C resulted in a stable and highly dispersed colloid. The writing test was performed on a white paper to show the potential use of the colloid for making security codes.

  3. PHOTOREFRACTIVE POLYMERS

    NARCIS (Netherlands)

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

    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

  4. 'One-component' ultrathin multilayer films based on poly(vinyl alcohol) as stabilizing coating for phenytoin-loaded liposomes.

    Science.gov (United States)

    Zasada, Katarzyna; Łukasiewicz-Atanasov, Magdalena; Kłysik, Katarzyna; Lewandowska-Łańcucka, Joanna; Gzyl-Malcher, Barbara; Puciul-Malinowska, Agnieszka; Karewicz, Anna; Nowakowska, Maria

    2015-11-01

    Ultrathin "one-component" multilayer polymeric films for potential biomedical applications were designed based on polyvinyl alcohol,-a non-toxic, fully degradable synthetic polymer. Good uniformity of the obtained film and adequate adsorption properties of the polymeric layers were achieved by functional modification of the polymer, which involved synthesis of cationic and anionic derivatives. Synthesized polymers were characterized by FTIR, NMR spectroscopy, dynamic light scattering measurements and elemental analysis. The layer by layer assembly technique was used to build up a multilayer film and this process was followed using UV-Vis spectroscopy and ellipsometry. The morphology and thickness of the obtained multilayered film material was evaluated by atomic force microscopy (AFM). Preliminary studies on the application of the obtained multilayer film for coating of liposomal nanocarriers containing phenytoin, an antiarrhythmic drug, were performed. The coating effectively stabilizes liposomes and the effect increases with an increasing number of deposited layers until the polymeric film reaches the optimal thickness. The obtained release profiles suggest that bilayer-coated liposomes release phenytoin less rapidly than uncoated ones. The cytotoxicity studies performed for all obtained nanocarriers confirmed that none of them has negative effect on cell viability. All of the performed experiments suggest that liposomes coated with ultrathin film obtained from PVA derivatives can be attractive drug nanocarriers. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. High efficiency chlorine removal from polyvinyl chloride (PVC) pyrolysis with a gas-liquid fluidized bed reactor.

    Science.gov (United States)

    Yuan, G; Chen, D; Yin, L; Wang, Z; Zhao, L; Wang, J Y

    2014-06-01

    In this research a gas-liquid fluidized bed reactor was developed for removing chlorine (Cl) from polyvinyl chloride (PVC) to favor its pyrolysis treatment. In order to efficiently remove Cl within a limited time before extensive generation of hydrocarbon products, the gas-liquid fluidized bed reactor was running at 280-320 °C, where hot N2 was used as fluidizing gas to fluidize the molten polymer, letting the molten polymer contact well with N2 to release Cl in form of HCl. Experimental results showed that dechlorination efficiency is mainly temperature dependent and 300 °C is a proper reaction temperature for efficient dechlorination within a limited time duration and for prevention of extensive pyrolysis; under this temperature 99.5% of Cl removal efficiency can be obtained within reaction time around 1 min after melting is completed as the flow rate of N2 gas was set around 0.47-0.85 Nm(3) kg(-1) for the molten PVC. Larger N2 flow rate and additives in PVC would enhance HCl release but did not change the final dechlorination efficiency; and excessive N2 flow rate should be avoided for prevention of polymer entrainment. HCl is emitted from PVC granules or scraps at the mean time they started to melt and the melting stage should be taken into consideration when design the gas-liquid fluidized bed reactor for dechlorination. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Enhancement of the thermal and mechanical properties of polyurethane/polyvinyl chloride blend by loading single walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    A.M. Hezma

    2017-06-01

    Full Text Available Structural, thermal, and mechanical properties of pure blend and nanocomposites based on polyurethane (PU and polyvinyl chloride (PVC doped with low different content of single walled-carbon nanotubes (SWCNTs were studied. The nanocomposites at different concentration were prepared via casting technique. The interaction between PU/PVC and CNTs were examined via FT-IR studies. The changes in the structures of the nanocomposites were examined using X- Ray Diffraction (XRD, and the results indicated that the amorphous domains of nanocomposites increased with increasing SWCNTs content. Transmission electron microscope (TEM observation indicated that SWCNTs surface was wrapped with the polymer with the thermal properties of nanocomposites improved. The mechanical behavior of the nanocomposites was evaluated as a function of SWCNTs content. The main enhancement in tensile properties was observed, e.g., the tensile strength and elastic modulus increased compared with the pure blend, which may be attributed to the interaction and adhesion between CNTs and the polymer matrices due to the hydrogen bonding between carbonyl groups (C=O of polymer blend chains and carboxylic acid (COOH groups of CNTs.

  7. Influence of the Polyvinyl Pyrrolidone Concentration on Particle Size and Dispersion of ZnS Nanoparticles Synthesized by Microwave Irradiation

    Directory of Open Access Journals (Sweden)

    Nayereh Soltani

    2012-09-01

    Full Text Available Zinc sulfide semiconductor nanoparticles were synthesized in an aqueous solution of polyvinyl pyrrolidone via a simple microwave irradiation method. The effect of the polymer concentration and the type of sulfur source on the particle size and dispersion of the final ZnS nanoparticle product was carefully examined. Microwave heating generally occurs by two main mechanisms: dipolar polarization of water and ionic conduction of precursors. The introduction of the polymer affects the heating rate by restriction of the rotational motion of dipole molecules and immobilization of ions. Consequently, our results show that the presence of the polymer strongly affects the nucleation and growth rates of the ZnS nanoparticles and therefore determines the average particle size and the dispersion. Moreover, we found that PVP adsorbed on the surface of the ZnS nanoparticles by interaction of the C–N and C=O with the nanoparticle’s surface, thereby affording protection from agglomeration by steric hindrance. Generally, with increasing PVP concentration, mono-dispersed colloidal solutions were obtained and at the optimal PVP concentration (5%, sufficiently small size and narrow size distributions were obtained from both sodium sulfide and thioacetamide sulfur sources. Finally, the sulfur source directly influences the reaction mechanism and the final particle morphology, as well as the average size.

  8. Influence of the polyvinyl pyrrolidone concentration on particle size and dispersion of ZnS nanoparticles sythesized by mcrowave iradiation.

    Science.gov (United States)

    Soltani, Nayereh; Saion, Elias; Erfani, Maryam; Rezaee, Khadijeh; Bahmanrokh, Ghazaleh; Drummen, Gregor P C; Bahrami, Afarin; Hussein, Mohd Zobir

    2012-09-27

    Zinc sulfide semiconductor nanoparticles were synthesized in an aqueous solution of polyvinyl pyrrolidone via a simple microwave irradiation method. The effect of the polymer concentration and the type of sulfur source on the particle size and dispersion of the final ZnS nanoparticle product was carefully examined. Microwave heating generally occurs by two main mechanisms: dipolar polarization of water and ionic conduction of precursors. The introduction of the polymer affects the heating rate by restriction of the rotational motion of dipole molecules and immobilization of ions. Consequently, our results show that the presence of the polymer strongly affects the nucleation and growth rates of the ZnS nanoparticles and therefore determines the average particle size and the dispersion. Moreover, we found that PVP adsorbed on the surface of the ZnS nanoparticles by interaction of the C-N and C=O with the nanoparticle's surface, thereby affording protection from agglomeration by steric hindrance. Generally, with increasing PVP concentration, mono-dispersed colloidal solutions were obtained and at the optimal PVP concentration (5%), sufficiently small size and narrow size distributions were obtained from both sodium sulfide and thioacetamide sulfur sources. Finally, the sulfur source directly influences the reaction mechanism and the final particle morphology, as well as the average size.

  9. Multi-frequency excitation

    KAUST Repository

    Younis, Mohammad I.

    2016-03-10

    Embodiments of multi-frequency excitation are described. In various embodiments, a natural frequency of a device may be determined. In turn, a first voltage amplitude and first fixed frequency of a first source of excitation can be selected for the device based on the natural frequency. Additionally, a second voltage amplitude of a second source of excitation can be selected for the device, and the first and second sources of excitation can be applied to the device. After applying the first and second sources of excitation, a frequency of the second source of excitation can be swept. Using the methods of multi- frequency excitation described herein, new operating frequencies, operating frequency ranges, resonance frequencies, resonance frequency ranges, and/or resonance responses can be achieved for devices and systems.

  10. Extraction of microcrystalline cellulose from rice straw and its effect on polyvinyl alcohol biocomposites film

    Science.gov (United States)

    Chin, Kwok-Mern; Ting, Sam Sung; Lin, Ong Hui; Owi, Wei Tieng

    2017-07-01

    The poor management and underutilization of agricultural wastes had proliferated interest of researchers around the world to find alternatives to utilize them as potential value-added products. One of the green alternatives is by extracting cellulose from these waste materials and incorporating them in polymer as reinforcement fillers. The surging amount of plastic waste also posed major issues to the environment due to its recalcitrance to degrade. Microcrystalline cellulose (MCC-RS) was extracted from rice straw through cyclic alkaline and bleaching treatment to remove hemicellulose and lignin respectively. Polyvinyl alcohol (PVOH) was chosen as the matrix and different ratios of PVOH / MCC-RS films were prepared (2.5, 5.0, 7.5 and 10.0wt% of MCC) through solution casting method and its tensile, thermal and morphological properties were studied. X-ray powder diffraction (XRD) results showed increased crystallinity of MCC-RS after chemical treatment (from 44.5% to 60.8%) due to the successful removal of lignin and hemicellulose, which was then confirmed with Fourier transform infrared spectroscopy (FTIR) results. For the biocomposites, both tensile strength and Young's modulus of the films increased with increasing MCC-RS content up until 7.5wt%, supported with scanning electron microscopy (SEM) results which depicted improvement in the interfacial adhesion between MCC-RS and PVOH. From the overall results, the improvement in properties of biocomposite from cellulose-based microfiller had shown promising future in application of the water soluble plastic packaging industry.

  11. Physical and chemical basics of modification of poly(vinyl chloride) by means of polyisocyanate

    Science.gov (United States)

    Islamov, Anvar; Fakhrutdinova, Venera; Abdrakhmanova, Lyailya

    2016-01-01

    This research presents data relating to polyvinyl chloride (PVC) modification by means of reactive oligomer and measures technological, physical and mechanical properties of the modified composites. Polyisocyanate (PIC) has been chosen as the modifying reactive oligomer. It has been shown that insertion of the oligomer has a double effect on PVC. Primarily, PIC produces a plasticizing effect on PVC and in particular leads to an increase in thermal stability and melt flow index at the stage of processing. In addition, the molded PVC composites possess higher strength properties and lower deformability when exposed to temperature because of chemical transformations of PIC in polymer matrix and, as the result, the formation of cross-linked systems takes place. In this case, semi-interpenetrating structures are formed based on cross-linked products of PIC chemical transformations homogeneously distributed in the PVC matrix. It has been determined by means of IR-spectroscopy that the basic products of PIC curing are compounds with urea and biuret groups which leads to modifying effect on PVC especially: increase in strength, thermal and mechanical properties, and chemical resistance.

  12. Hierarchial coassembly of a cyanine dye in poly(vinyl alcohol) fibrous films by electrospinning.

    Science.gov (United States)

    Demir, Mustafa M; Horzum, Nesrin; Özen, Bengisu; Özçelik, Serdar

    2013-09-19

    We report molecular aggregate formation of TTBC (1,1',3,3'-tetraethyl-5,5',6,6'-tetrachlorobenzimidazolocarbocyanine) in submicrometer-sized PVA (poly(vinyl alcohol)) fibers by electrospinning. The formation of the molecular aggregate is examined by solution and instrumental parameters of electrospinning. The precursor solution of PVA/TTBC, in the range of 0.016-0.065 wt % is subjected to electrospinning under an electrical field ranging from 0.95 to 1.81 kV cm(-1). Both randomly deposited and uniaxially aligned fibers are achieved by using two parallel-positioned metal strips as counter electrode. Photoluminescence and polarized Fourier transform infrared spectroscopies are employed to determine spectral properties of the fibers. H-aggregates are formed within the electrospun fibers, regardless of their alignment, and H- and J-type aggregates coexist in the alternative spin-coated and the cast films. A strongly polarized photoluminescence emission is observed in the direction of uniaxially aligned fibers as a result of the orientation of the H-aggregates along the fiber axis. We demonstrate that electrospinning is a process capable of forming and orienting TTBC aggregates during the structural development of the polymer/dye nanofibers. These fibrous films may potentially find applications in optics and electronics.

  13. Toward "strong" green nanocomposites: polyvinyl alcohol reinforced with extremely oriented cellulose whiskers.

    Science.gov (United States)

    Jalal Uddin, Ahmed; Araki, Jun; Gotoh, Yasuo

    2011-03-14

    To exploit the maximum potential of cellulose whiskers (CWs), we report here for the first time the successful fabrication of nanocomposites reinforced with highly oriented CWs in a polymer matrix. The nanocomposites were prepared using polyvinyl alcohol (PVA) and a colloidal suspension of cotton-derived CWs. The macroscopically homogeneous PVA-CW suspensions were extruded into cold methanol to form gel fibers followed by a hot drawing. Compared to the neat PVA fiber, the as-spun fiber containing a small amount of CWs (5 wt % of solid PVA) showed higher drawability, leading to an extremely high orientation of CWs with the matrix PVA. The stress-transfer mechanism, a prime determining factor for high mechanical properties of nanocomposites, was studied by X-ray diffraction. The stress on the incorporated CWs was monitored by applying an in situ nondestructive load to the composite fibers. The applied stress to the whole sample was found to be effectively transferred to the CWs inside the composites, suggesting strong interfacial bonding between the filler and the matrix. Effective stress transfer to the oriented whiskers resulted in outstanding enhancement in mechanical properties of the nanocomposites.

  14. Short Oligonucleotides Aligned in Stretched Humid Matrix: Secondary DNA Structure in Poly(vinyl alcohol) Environment

    KAUST Repository

    Hanczyc, Piotr

    2012-04-24

    We report that short, synthetic, double- as well as single-stranded DNA can be aligned in stretched humid poly(vinyl alcohol) (PVA) matrix, and the secondary structure (nucleobase orientation) can be characterized with linear dichroism (LD) spectroscopy. Oligonucleotides of lengths varying between 10 (3.4 nm) and 60 bases (20.4 nm) were investigated with respect to structural properties in the gel-like polymer environment. The DNA conformation as a function of relative humidity reveals a strong dependence of helical structure of DNA on PVA hydration level, results of relevance for nanotechnical studies of DNA-based supramolecular systems. Also, the PVA gel could provide possibilities to test models for nucleic acid interactions and distribution in cell contexts, including structural stability of genetic material in the cell and PVA-packaging for gene delivery. A method by which duplex oligonucleotides, with sequences designed to provide specific binding sites, become amenable to polarized-light spectroscopy opens up new possibilities for studying structure in DNA complexes with small adduct molecules as well as proteins. © 2012 American Chemical Society.

  15. Heat Capacity, Crystallization, and Nucleation in Poly(vinyl alcohol) Thin Films

    Science.gov (United States)

    Thomas, David; Wurm, Andreas; Zhuravlev, Evgeny; Schick, Christoph; Cebe, Peggy

    Polyvinyl alcohol (PVA) is hydrophilic, biodegradable, semi-crystalline polymer with a wide array of applications ranging from textiles and packaging to medicine. Despite possessing favorable properties, PVA thermally degrades at temperatures just in excess of 200 °C which occurs slightly below the observed peak endothermic melting peak at 203 °C. Utilizing fast scanning calorimetry it is possible to minimize sample degradation allowing measurements of the liquid phase heat capacity as well as study nucleation and crystallization from the amorphous melt state. Samples cut from parent films 2-3 μm thick were placed on UFSC1 sensors and brought between -80 and 270 °C at rates of 2000 °C/s under a nitrogen atmosphere. After five complete cycles samples did not show any signs of degradation. By fitting the symmetry corrected glassy phase heat capacity with literature values for the specific heat capacity from the ATHAS databank sample masses were determined to vary between 15-50 ng. Homogeneous nucleation was observed for all samples cooled from the melt with peak temperature 123 °C. Fitting linear heat capacity baselines in the melt and glassy states it was possible to obtain an experimental measurement of the heat capacity increment 44.5 J/mol K at the glass transition 85 °C. NSF DMR-1206010.

  16. Amphiphilic conjunct of methyl cellulose and well-defined polyvinyl acetate.

    Science.gov (United States)

    Xiao, Congming; Xia, Cunping

    2013-01-01

    Tailor-made conjunct of methyl cellulose (MC) and polyvinyl acetate (PVAc) was synthesized through the combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and thiol-ene click reaction. MC was firstly transferred into unsaturated MC (UMC), and then covalently connected with well-defined PVAc obtained by RAFT polymerization of vinyl acetate. The structure of the conjunct polymer (MCV) was confirmed with Fourier transform infrared spectra (FTIR) and proton nuclear magnetic resonance ((1)H NMR). Well-defined MCV was amphiphilic and able to self-assemble into size controllable micelles, which was verified with transmission electron microscopy (TEM) and size distribution analysis. It was found that the mean diameters of the micelles in aqueous solution were 105.6, 96.0 and 75.9 nm when the number average molecular weights of PVAc segments of MCV were 49,300, 32,500 and 18,200, respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Ultrasonic assisted microwave synthesis of poly (Chitosan-co-gelatin)/polyvinyl pyrrolidone IPN hydrogel.

    Science.gov (United States)

    Wang, Yajuan; Zhang, Xin; Qiu, Dan; Li, Ya; Yao, Lihui; Duan, Jingkuan

    2018-01-01

    The hydrogels based on gelatin cross-linked with chitosan (CS) and polyvinyl pyrrolidone (PVP) were synthesized using microwave and ultrasonic coupling technique in this study. This interpenetrating polymer network (IPN) hydrogels were cross-linked by glutaraldehyde and 1,2-Epoxy-4-vinylcyclohexane. The presence of function groups in the structure of hydrogel films were confirmed using Fourier transform infrared spectroscopy (FT-IR), thermal stability was measured by DSC, and the swelling behaviors were measured gravimetrically in distilled water at the temperature of 27°C. At last, the mechanical properties were tested. The results showed that the hydrogel prepared with microwave and ultrasonic exhibited the highest tensile strength (86.68MPa), comparing with the hydrogel prepared with traditional method and only microwave reactive field. The FT-IR and XRD results showed that the chemical reactions occurred between the NH2 of chitosan and the COOH of gelatin, and the introduction of ultrasound can improve the reaction rate. The hydrogel film gained in microwave and ultrasonic coupling field has the best combination properties. Therefore, the new microwave-ultrasonic coupling technique is the potential technology to prepare the new hydrogel due to less synthesis time. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Thermal effects on the electrical properties of (methyl orange)/ (polyvinyl alcohol) composites

    Science.gov (United States)

    de Oliveira, Helinando P.; de Melo, Celso P.

    2007-04-01

    We have used electrical impedance spectroscopy to determine the dielectric characteristics of polymeric films prepared by incorporating varying amounts of methyl orange (MO), an azobenzene dye, into solid films of polyvinyl alcohol (PVA), an insulating polymer. By mapping the variation of relevant parameters such as the dielectric relaxation time, we have analyzed how thermal effects would affect the charge transport and polarization processes in the MO/PVA composite samples as the frequency of an applied external field and the temperature were varied in a controlled manner. We interpret the results in terms of number and size of the dye aggregates in the polymeric matrix, by correlating thermal and polarization effects to the temperature and the relative amount of MO in the composite films. Finally, we show that the electrical characteristics of the MO/PVA samples can be modified by light incidence, a fact that confirms the possibility of using these composites in (light written)-(electrically read) solid-state memory devices.

  19. 1H NMR Self-Diffusion Study of Morphology and Structure of Polyvinyl Alcohol Cryogels.

    Science.gov (United States)

    Shapiro

    1999-04-15

    The multicomponent self-diffusion of the polyvinyl alcohol (PVA) cryogels prepared by a freezing-thawing treatment of aqueous and water-DMSO solutions of PVA has been studied with the NMR FT-PGSE method. The temperature dependencies of the self-diffusion coefficients, Ds, for the PVA chains have a maximum at 45 degrees C due to the syneresis of cryogels. They are quite different from the monotonous increase of Ds for the aqueous solutions of PVA. Evaluated apparent activation energies, Ea, of the self-diffusion for the PVA chains in the PVA solutions and cryogels in D2O are practically the same and equal 22-24 kJ/mol below the crucial point. The proton spin-lattice relaxation times, T1, of the PVA chain also coincide with one another for solutions and cryogels. This means that molecular packing in cryogels depends mainly on the dimensions of the ice and polymer microcrystallites formed by freezing the solution. Above the crucial point polymer compartments become firmer, and the chain mobility somewhat reduces. The strength of cryogels also increases along with growing the DMSO contents and decreases by the BSA addition. For estimation of the cryogel morphology, effects of the restricted diffusion of both the water and PVA in a q-space have been taken into account. By the introduction of DMSO to cryogels the solvent filled pores become smaller, and channels become much shorter. The diameter of the PVA filaments is similar to those for all the cryogels, but the length of filaments with D2O is twice that for cryogels with a mixed solvent. Entrapment of BSA in the cryogel matrix by preparation leads to the increase of an average diameter of the water filled pores and destroys molecular packing the cryogel. Copyright 1999 Academic Press.

  20. An intensive study on the optical, rheological, and electrokinetic properties of polyvinyl alcohol-capped nanogold

    Science.gov (United States)

    Behera, Manoranjan

    2015-05-01

    Low-temperature-assisted wet chemical synthesis of nanogold (NG) using gold hydroxide, a new precursor salt in the presence of a macroscopic ligand poly(vinyl alcohol) PVA in water in the form of nanofluid, is reported for the first time in this article. In the absorption spectra, the surface Plasmon resonance absorption band in the range of 520-545 nm signifies the formation of NG via a controlled Au3+ + 3e → Au reaction grafted in small assemblies with polymer. Absorption maximum increases nonlinearly with Au-contents up to 100 µM Au in Au-PVA charge-transfer complex. Marked enhancement in the peak intensity of some of the vibration bands of PVA polymer such as C-H stretching, C=O stretching, CH2 bending, and C-C in-plane bending in the presence of NG reveals an interfacial interaction between NG and oxidized PVA via C=O group. Execution of shear thinning behavior regardless of the Au-content strongly suggests that crosslinking exists between NG and PVA in Au-PVA rheo-optical nanofluids. Hydrodynamic diameter and polydispersity index draw a nonlinear path with the Au doping with 30.0 g/L PVA in water over a wide region of 5-100 μM Au covered in this study. Enhancement in the zetapotential of Au-PVA nanofluid over bare PVA in water is ascribed to buildup of nonbonding electrons of "-C=O" moieties from the oxidized PVA on the NG surface. Displaying of lattice fringes in the microscopic image of core-shell Au-PVA nanostructure confirms that crystalline nature of NG core with inter planar spacing 0.235 nm corresponds to Au (111) plane.

  1. Fittings of unplasticized polyvinyl chloride (PVC-U), chlorinated polyvinyl chloride (PVC-C) or acrylonitrile/butadiene/styrene (ABS) with plain sockets for pipes under pressure - Dimensions of sockets - Metric series

    CERN Document Server

    International Organization for Standardization. Geneva

    1985-01-01

    Fittings of unplasticized polyvinyl chloride (PVC-U), chlorinated polyvinyl chloride (PVC-C) or acrylonitrile/butadiene/styrene (ABS) with plain sockets for pipes under pressure - Dimensions of sockets - Metric series

  2. Plastics piping systems for industrial applications : acrylonitrile-butadiene- styrene (ABS), unplasticized poly(vinyl chloride) (PVC-U) and chlorinated poly(vinyl chloride) (PVC-C) : specifications for components and the system : metric series

    CERN Document Server

    International Organization for Standardization. Geneva

    2003-01-01

    Plastics piping systems for industrial applications : acrylonitrile-butadiene- styrene (ABS), unplasticized poly(vinyl chloride) (PVC-U) and chlorinated poly(vinyl chloride) (PVC-C) : specifications for components and the system : metric series

  3. Supramolecular Polymers

    Science.gov (United States)

    Stupp, S. I.; Keser, M.; Huggins, K. E.; Tew, G.; Li, L. S.; Whitaker, C.

    1997-03-01

    An interesting target in polymer science is to find pathways to highly regular supramolecular units with dimensions similar to those of high molar mass linear or hyperbranched polymers. These units lack a polymeric backbone but could serve as precursors to shape invariant covalent polymers analogous to folded proteins. We are pursuing access to these polymers with designed molecules programmed to assemble into nanostructures of regular shape and dimension. We have discovered systems of miniaturized triblock copolymers that yield supramolecular polymers. These supramolecular polymers are shaped as mushroom nanostructures, and form materials with interesting surface and optical properties. Molecular modeling indicates that a balance of aggregation and hard core repulsive forces among structural units may be responsible for the formation of these supramolecular polymers.

  4. Optical Properties Of Hybrid Composites Based On Highly Luminescent CdS and ZnS Nanocrystals In Different Polymer Matrices

    Science.gov (United States)

    Pandey, Shipra; Pandey, Avinash C.

    2009-06-01

    The luminescent CdS and ZnS nanocystals embedded in different polymer matrices like polyvinyl alcohol (PVA), poly-vinyl pyridine (PVP) polymer matrices have been prepared by simple wet chemical precipitation method. The thin films of nanocomposites are deposited on glass substrate by spin-coating. The optical absorption spectra show a clear blue shift in absorption edge, such that the band gap calculated from the absorption spectra are higher than those calculated for the bulk. Photoluminescence spectra show defect related emission at different wavelength in visible range.

  5. Polymer adsorption and its effect on the Stability of hydrophobic colloids. III. Kinetics of th Flocculation of silver iodide sols

    NARCIS (Netherlands)

    Fleer, G.J.; Lyklema, J.

    1976-01-01

    In a previous study on the flocculation of silver iodide sols by polyvinyl alcohol (PVA) it was demonstrated that the extent of flocculation depends critically on the way in which sol particles and polymer are mixed. Optimal flocculation was shown to occur if a two-portion method of mixing is

  6. Preparation and characterization of electrically conductive composites of poly(vinyl alcohol–g–poly(acrylic acid hydrogels impregnated with polyaniline (PANI

    Directory of Open Access Journals (Sweden)

    2008-01-01

    Full Text Available Novel electrically conducting composite materials consisting of poly(aniline (PANI nanoparticles dispersed in a poly(vinyl alcohol (PVA-g-poly(acrylic acid (PAA hydrogels were prepared within the polymer matrix by in situ polymerization of aniline. The conversion yield of aniline into PANI particles was determined gravimetrically while structural confirmation of the synthesized polymer was sought by Fourier Transform Infrared (FTIR, UV-visible analysis and X-ray diffraction (XRD technique. Morphology and dimension of PANI particles embedded into the colored optically semi-transparent hydrogels were evaluated by Scanning Electron Microscopy (SEM analysis. Electrical conductivity of composite hydrogels of different composition was determined by LCR meter while electroactive behavior of composite hydrogels swollen in electrolyte solution was investigated by Effective Bend Angle (EBA measurements.

  7. The influence of polyvinyl chloride (P.V.C.) tubing on the isolated perfused rat heart

    NARCIS (Netherlands)

    Meijler, F.L.; Willebrands, A.F.; Durrer, D.

    1960-01-01

    Some brands of polyvinyl chlorides interfere with cardiac contraction, whereas other brands do not. Chemical investigation showed that the stabilizer is most probably responsibie for the cardiotoxic effect. It is suggested that all types of polyvinyl chloride used for medical and biological

  8. De invloed van plastic (polyvinyl-chloride) op het geïsoleerde overlevende rattehart

    NARCIS (Netherlands)

    Meijler, F.L.; Willebrands, A.F.; Durrer, D.

    1959-01-01

    Sommige soorten plastic(polyvinyl-chloride)slang doen de mechanische activiteit van het overlevende, geïsoleerde rattehart verminderen, of verdwijnen. Dit polyvinyl-chloride wordt verkocht en gebruikt voor medische en biologische doeleinden. Chemische analyses toonden een duidelijk verschil tussen

  9. PVC-PBMA nanocomposite polymer electrolytes for lithium battery applications

    Science.gov (United States)

    Arunkumar, R.; Rani, M. Usha; Babu, Ravishanker

    2017-05-01

    Polyvinyl chloride (PVC)-Poly (butyl methacrylate) (PBMA) composite polymer electrolytes with incorporation of different ratio of ZrO2 doped was prepared by solution casting technique. The ionic conductivity, dielectric behavior, ionic transference number and surface morphology of the composite polymer electrolytes were characterized by using ac impedance, dielectric, DC polarization method and SEM studies respectively. The best room temperature ionic conductivity (0.520mScm-1 at 303 K), high dielectric constant (27340 ± 10 at 50 Hz) and high pore size obtained for 10 wt% of ZrO2 doped composite polymer electrolytes. DC polarization method confirms the occurrences of conduction in composite PVC-PBMA blend polymer electrolytes predominantly due to ions.

  10. Excited states 2

    CERN Document Server

    Lim, Edward C

    2013-01-01

    Excited States, Volume 2 is a collection of papers that deals with molecules in the excited states. The book describes the geometries of molecules in the excited electronic states. One paper describes the geometries of a diatomic molecule and of polyatomic molecules; it also discusses the determination of the many excited state geometries of molecules with two, three, or four atoms by techniques similar to diatomic spectroscopy. Another paper introduces an ordered theory related to excitons in pure and mixed molecular crystals. This paper also presents some experimental data such as those invo

  11. 78 FR 37794 - Polyvinyl Alcohol from Taiwan: Final Results of Antidumping Duty Administrative Review; 2010-2012

    Science.gov (United States)

    2013-06-24

    ... International Trade Administration Polyvinyl Alcohol from Taiwan: Final Results of Antidumping Duty... results of the administrative review of the antidumping duty order on polyvinyl alcohol (PVA) from Taiwan... February 29, 2012. \\1\\ See Polyvinyl Alcohol From Taiwan: Preliminary Results of Antidumping Duty...

  12. Polymer hydrogels as optimized delivery systems

    Energy Technology Data Exchange (ETDEWEB)

    Batista, Jorge G.S.; Varca, Gustavo H.C.; Ferraz, Caroline C.; Garrido, Gabriela P.; Diniz, Bruna M.; Carvalho, Vinicius S.; Lugao, Ademar B., E-mail: jorgegabriel@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Hydrogels are formed by polymers capable of absorbing large quantities of water. They consist of one or more three-dimensionally structured polymer networks formed by macromolecular chains linked by covalent bonds-crosslinks - and physical interactions. The application of hydrogels, has been widely studied. Biodegradable synthetic or natural polymers such as chitosan, starch and poly-lactic-co-glycolic acid, have properties that allow the development of biodegradable systems for drug and nutraceutics delivery. This study aimed to develop polymeric hydrogels based on polyvinyl alcohol, polyacrylamide and polyvinylpyrrolidone using ionizing radiation in order to develop hydrogels for improved loading and release of compounds. Polymer solutions were solubilized in water and poured into thermoformed packages. After sealing, the material was subjected to γ-irradiation at 25kGy. The samples were assayed by means of mechanical properties, gel fraction and swelling degree. Nanostructure characterization was performed using Flory's equation to determine crosslinking density. The systems developed showed swelling degree and adequate mechanical resistance. The nanostructure evaluation showed different results for each system demonstrating the need of choosing the polymer based on the specific properties of each material. (author)

  13. Polymer Electrolytes

    Science.gov (United States)

    Hallinan, Daniel T.; Balsara, Nitash P.

    2013-07-01

    This review article covers applications in which polymer electrolytes are used: lithium batteries, fuel cells, and water desalination. The ideas of electrochemical potential, salt activity, and ion transport are presented in the context of these applications. Potential is defined, and we show how a cell potential measurement can be used to ascertain salt activity. The transport parameters needed to fully specify a binary electrolyte (salt + solvent) are presented. We define five fundamentally different types of homogeneous electrolytes: type I (classical liquid electrolytes), type II (gel electrolytes), type III (dry polymer electrolytes), type IV (dry single-ion-conducting polymer electrolytes), and type V (solvated single-ion-conducting polymer electrolytes). Typical values of transport parameters are provided for all types of electrolytes. Comparison among the values provides insight into the transport mechanisms occurring in polymer electrolytes. It is desirable to decouple the mechanical properties of polymer electrolyte membranes from the ionic conductivity. One way to accomplish this is through the development of microphase-separated polymers, wherein one of the microphases conducts ions while the other enhances the mechanical rigidity of the heterogeneous polymer electrolyte. We cover all three types of conducting polymer electrolyte phases (types III, IV, and V). We present a simple framework that relates the transport parameters of heterogeneous electrolytes to homogeneous analogs. We conclude by discussing electrochemical stability of electrolytes and the effects of water contamination because of their relevance to applications such as lithium ion batteries.

  14. Star Polymers.

    Science.gov (United States)

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  15. 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.

  16. A Model Approach for Finding Cleaning Solutions for Plasticized Poly(Vinyl Chloride) Surfaces of Collections Objects

    DEFF Research Database (Denmark)

    Sanz Landaluze, Jon; Egsgaard, Helge; Morales Munoz, Clara

    2014-01-01

    This study focused on developing a surface cleaning treatment for one type of commercially available plasticized poly(vinyl chloride). The effects of cleaning solutions on samples of plasticized poly(vinyl chloride) were examined by several methods. The sample surface, prior to and after artificial...... solutions for the plasticized poly(vinyl chloride) used in the study was found. In addition, a specific method to tailor cleaning mixtures for plasticized poly(vinyl chloride) objects was developed by means of Hildebrand solubility parameters and the formulation of a Plasticizer Index calculated...... cleaning methods for plasticized poly(vinyl chloride) objects....

  17. Flexible polymers at a solid-liquid interface : the adsorption of polyvinyl pyrrolidone onto silica

    NARCIS (Netherlands)

    Cohen Stuart, M.A.

    1980-01-01

    We undertook the present study in order to evaluate techniques which are devised to assess the comformations of adsorbed macromolecules. Since recent theories deal with these conformations, we also wanted to investigate to what extent these theories are supported by experimental data.
    In

  18. Development and evaluation of polyvinyl-alcohol blend polymer films as battery separators

    Science.gov (United States)

    Manzo, M. A.

    1982-01-01

    Several dialdehydes and epoxies were evaluated for their suitability as cross-linkers. Optium concentrations of several cross-linking reagents were determined. A two-step method of cross-linking, which involves treatment of the film in an acid or acid periodate bath, was investigated and dropped in favor of a one-step method in which the acid catalyst, which initiates cross-linking, is added to the PVA - cross-linker solution before casting. The cross-linking was thus achieved during the drying step. This one-step method was much more adaptable to commercial processing. Cross-linked films were characterized as alkaline battery separators. Films were prepared in the lab and tested in cells in order to evaluate the effect of film composition and a number of processing parameters on cell performance. These tests were conducted in order to provide a broader data base from which to select optimum processing parameters. Results of the separator screening tests and the cell tests are discussed.

  19. Polyaniline - Carrageenan - Polyvinyl Alcohol Composite Material Synthesized Via Interfacial Polymerization, its Morphological Characteristics and Enhanced Solubility in Water

    Science.gov (United States)

    Montalbo, R. C. K.; Marquez, M. C.

    2017-09-01

    In recent years, conducting polyaniline (PAni) has been a popular interest of research in the field of conducting polymers due to its relatively low cost, ease of production, good conductivity, and environmental stability. Many studies however, have focused on improving its short-comings such as its limited processability and solubility in common solvents. In this study, PAni, soluble in water was produced via interfacial polymerization with chloroform as the organic solvent. Poly(vinyl alcohol) (PVA) and kappa(κ), iota(ι) and lambda(λ) - carrageenan (κCGN, ιCGN, λCGN) were added to the aqueous layer to stabilize PAni in the medium. FTIR and UV-Vis absorption spectra of the solutions as well as the fabricated film confirmed the existence of PAni emeraldine salt (PAni-ES). FTIR spectrum also confirmed the peaks corresponding to the interaction of PAni with the CGNs. Moreover, PVA-CGN played a very large role on the stability of the PAni nanofibers integrated on the PVA-CGN matrix. The morphologies of the products were further investigated using SEM and TEM. Polymer electrolyte for supercapacitor or an interfacial layer for organic solar cell is being targeted as potential application of the synthesized water soluble PAni.

  20. Synthesis and characterization of polyvinyl alcohol/cellulose cryogels and their testing as carriers for a bioactive component

    Energy Technology Data Exchange (ETDEWEB)

    Paduraru, Oana Maria; Ciolacu, Diana; Darie, Raluca Nicoleta; Vasile, Cornelia, E-mail: cvasile@icmpp.ro

    2012-12-01

    Novel physically cross-linked cryogels containing polyvinyl alcohol (PVA) and various amounts of microcrystalline cellulose were obtained by freezing/thawing technique. The main goal of this study was to improve the properties and the performances of the pure PVA cryogels. The morphological aspects of the cryogels were studied by scanning electron microscopy (SEM). The Fourier transform infrared spectroscopy (FT-IR) was used to reveal the presence of the interactions between the two polymers. Changes in crystallinity of the samples were confirmed by X-ray diffraction (XRD) and by FT-IR spectroscopy. The modification of the thermal behavior induced by cellulose was studied by thermogravimetry. Rheological analysis revealed higher values of storage modulus (G Prime ) for the cryogels containing higher amounts of cellulose. The degree and rate of swelling were controlled by the presence of the natural polymer in the network. The potential application as bioactive compound carriers was tested, using vanillin as an active agent. Highlights: Black-Right-Pointing-Pointer Novel PVA/microcrystalline cellulose cryogels were obtained by freezing/thawing. Black-Right-Pointing-Pointer The main advantage of this technique is that no chemical crosslinker is being used. Black-Right-Pointing-Pointer The presence of cellulose improves the swelling properties and the cryogels' strength. Black-Right-Pointing-Pointer The potential application as carriers for bioactive components was tested.

  1. A novel approach for fabricating highly tunable and fluffy bioinspired 3D poly(vinyl alcohol) (PVA) fiber scaffolds.

    Science.gov (United States)

    Roy, Sunanda; Kuddannaya, Shreyas; Das, Tanya; Lee, Heng Yeong; Lim, Jacob; Hu, Xiao 'Matthew'; Chee Yoon, Yue; Kim, Jaehwan

    2017-06-01

    The excellent biocompatibility, biodegradability and chemo-thermal stability of poly(vinyl alcohol) (PVA) have been harnessed in diverse practical applications. These properties have motivated the fabrication of high performance PVA based nanofibers with adequate control over the micro and nano-architectures and surface chemical interactions. However, the high water solubility and hydrophilicity of the PVA polymer limits the application of the electrospun PVA nanofibers in aqueous environments owing to instantaneous dissolution. In this work, we report a novel yet facile concept for fabricating extremely light, fluffy, insoluble and stable three dimensional (3D) PVA fibrous scaffolds with/without coating for multifunctional purposes. While the solubility, morphology, fiber density and mechanical properties of nanofibers could be tuned by optimizing the cross-linking conditions, the surface chemical reactivity could be readily enhanced by coating with a polydopamine (pDA) bioinspired polymer without compromising the stability and innate properties of the native PVA fiber. The 3D pDA-PVA scaffolds exhibited super dye adsorption and constructive synergistic cell-material interactions by promoting healthy adhesion and viability of the human mesenchymal stem cells (hMSCs) within 3D micro-niches. We foresee the application of tunable PVA 3D as a highly adsorbent material and a scaffold material for tissue regeneration and drug delivery with close consideration of realistic in vivo parameters.

  2. Fabrication of a biodegradable calcium polyphosphate/polyvinyl-urethane carbonate composite for high load bearing osteosynthesis applications.

    Science.gov (United States)

    Ramsay, Scott D; Pilliar, Robert M; Santerre, J Paul

    2010-07-01

    The formation of biodegradable implants for use in osteosynthesis has been a major goal of biomaterials research for the past 2-3 decades. Self-reinforced polylactide systems represent the most significant success of this research to date, however, with elastic constants up to 12-15 GPa at best, they fail to provide the initial stiffness required of devices for stabilizing fractures of major load-bearing bones. Our research has investigated the use of calcium polyphosphate (CPP), an inorganic polymer in combination with polyvinyl-urethane carbonate (PVUC) organic polymers for such applications. Initial studies indicated that composite samples formed as interpenetrating phase composites (IPC) exhibited suitable as-made strength and stiffness, however, they displayed a rapid loss of properties when exposed to in vitro aging. An investigation to determine the mechanism of this accelerated in vitro degradation for the IPCs as well as to identify possible design changes to overcome this drawback was undertaken using a model IPC system. It was found that strong interfacial strength and minimal swelling of the PVUC are very important for obtaining and maintaining appropriate mechanical properties in vitro. (c) 2010 Wiley Periodicals, Inc.

  3. Branched polymers on branched polymers

    OpenAIRE

    Durhuus, Bergfinnur; Jonsson, Thordur

    1996-01-01

    We study an ensemble of branched polymers which are embedded on other branched polymers. This is a toy model which allows us to study explicitly the reaction of a statistical system on an underlying geometrical structure, a problem of interest in the study of the interaction of matter and quantized gravity. We find a phase transition at which the embedded polymers begin to cover the basis polymers. At the phase transition point the susceptibility exponent $\\gamma$ takes the value 3/4 and the ...

  4. Conducting Polymers

    Indian Academy of Sciences (India)

    potential of the monomer would be less than that of the dimer, which would in turn be less than that of the polymer. Hence, the polymer generated by this oxidative .... glucose and galactose biosensors based on a silicon chip employing polypyrrole have in fact been developed by several companies. These types of sensors ...

  5. Conducting Polymers

    Indian Academy of Sciences (India)

    polymer backbone), exhibit semiconducting behavior. The discovery of dopingl led to a further dramatic increase in the conductivity of such conjugated polymers to values as ..... CERF's Comments on Modem Science. • If it's incomprehensible, it's mathematics. • If it doesn't make sense, it's either economics or psychology.

  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. Recycling of polymers: a review.

    Science.gov (United States)

    Ignatyev, Igor A; Thielemans, Wim; Vander Beke, Bob

    2014-06-01

    Plastics are inexpensive, easy to mold, and lightweight. These and many other advantages make them very promising candidates for commercial applications. In many areas, they have substantially suppressed traditional materials. However, the problem of recycling still is a major challenge. There are both technological and economic issues that restrain the progress in this field. Herein, a state-of-art overview of recycling is provided together with an outlook for the future by using popular polymers such as polyolefins, poly(vinyl chloride), polyurethane, and poly(ethylene terephthalate) as examples. Different types of recycling, primary, secondary, tertiary, quaternary, and biological recycling, are discussed together with related issues, such as compatibilization and cross-linking. There are various projects in the European Union on research and application of these recycling approaches; selected examples are provided in this article. Their progress is mirrored by granted patents, most of which have a very limited scope and narrowly cover certain technologies. Global introduction of waste utilization techniques to the polymer market is currently not fully developed, but has an enormous potential. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Excited states 4

    CERN Document Server

    Lim, Edward C

    2013-01-01

    Excited States, Volume 4 is a collection of papers that deals with the excited states of molecular activity. One paper investigates the resonance Raman spectroscopy as the key to vibrational-electronic coupling. This paper reviews the basic theory of Raman scattering; it also explains the derivation of the Raman spectra, excitation profiles, and depolarization ratios for simple resonance systems. Another paper reviews the magnetic properties of triplet states, including the zero-field resonance techniques, the high-field experiments, and the spin Hamiltonian. This paper focuses on the magnetic

  9. Nuclear expansion with excitation

    Energy Technology Data Exchange (ETDEWEB)

    De, J.N. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Departament d' Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain); Samaddar, S.K. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Vinas, X. [Departament d' Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain); Centelles, M. [Departament d' Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona (Spain)]. E-mail: mario@ecm.ub.es

    2006-07-06

    The expansion of an isolated hot spherical nucleus with excitation energy and its caloric curve are studied in a thermodynamic model with the SkM{sup *} force as the nuclear effective two-body interaction. The calted results are shown to compare well with the recent experimental data from energetic nuclear collisions. The fluctuations in temperature and density are also studied. They are seen to build up very rapidly beyond an excitation energy of {approx}9 MeV/u. Volume-conserving quadrupole deformation in addition to expansion indicates, however, nuclear disassembly above an excitation energy of {approx}4 MeV/u.

  10. Excitation energy transfer processes in condensed matter theory and applications

    CERN Document Server

    Singh, Jai

    1994-01-01

    Applying a unified quantum approach, contributors offer fresh insights into the theoretical developments in the excitation energy transfer processes in condensed matter This comprehensive volume examines Frenkel and Wannier excitonic processes; rates of excitonic processes; theory of laser sputter and polymer ablation; and polarons, excitonic polarons and self-trapping

  11. "One-Pot" Fabrication of Highly Versatile and Biocompatible Poly(vinyl alcohol)-porphyrin-based Nanotheranostics.

    Science.gov (United States)

    Luo, Yan; Wu, Hao; Feng, Caihong; Xiao, Kai; Yang, Xixiao; Liu, Qiangqiang; Lin, Tzu-Yin; Zhang, Hongyong; Walton, Jeffrey H; Ajena, Yousif; Hu, Yide; Lam, Kit S; Li, Yuanpei

    2017-01-01

    Nanoparticle-based theranostic agents have emerged as a new paradigm in nanomedicine field for integration of multimodal imaging and therapeutic functions within a single platform. However, the clinical translation of these agents is severely limited by the complexity of fabrication, long-term toxicity of the materials, and unfavorable biodistributions. Here we report an extremely simple and robust approach to develop highly versatile and biocompatible theranostic poly(vinyl alcohol)-porphyrin nanoparticles (PPNs). Through a "one-pot" fabrication process, including the chelation of metal ions and encapsulation of hydrophobic drugs, monodispersenanoparticle could be formed by self-assembly of a very simple and biocompatible building block (poly(vinyl alcohol)-porphyrin conjugate). Using this approach, we could conveniently produce multifunctional PPNs that integrate optical imaging, positron emission tomography (PET), photodynamic therapy (PDT), photothermal therapy (PTT) and drug delivery functions in one formulation. PPNs exhibited unique architecture-dependent fluorescence self-quenching, as well as photodynamic- and photothermal- properties. Near-infrared fluorescence could be amplified upon PPN dissociation, providing feasibility of low-background fluorescence imaging. Doxorubicin (DOX)-loaded PPNs achieved 53 times longer half-life in blood circulation than free DOX. Upon irradiation by near infrared light at a single excitation wavelength, PPNs could be activated to release reactive oxygen species, heat and drugs simultaneously at the tumor sites in mice bearing tumor xenograft, resulting in complete eradication of tumors. Due to their organic compositions, PPNs showed no obvious cytotoxicity in mice via intravenous administration during therapeutic studies. This highly versatile and multifunctional PPN theranostic nanoplatform showed great potential for the integration of multimodal imaging and therapeutic functions towards personalized nanomedicine against

  12. Myoglobin entrapment in poly(vinyl alcohol dense membranes

    Directory of Open Access Journals (Sweden)

    K. C. S. Figueiredo

    2014-09-01

    Full Text Available Our goal in this study was the immobilization of myoglobin in poly(vinyl alcohol dense membranes. Glutaraldehyde was investigated both as the crosslinking agent, aiming to increase the membrane stability in aqueous medium, and as the vehicle to bind myoglobin and PVA. Reaction and membrane synthesis were carried simultaneously in mild operating conditions in order to maintain the native protein folding. Membrane characterization comprised the water swelling degree, DSC, TGA, UV-visible spectroscopy, FTIR analysis and oxygen transport in a dialysis cell. The incorporation of myoglobin in the film decreased the water swelling degree and improved the membrane thermal properties compared to unmodified PVA membrane. The reduction of ferric iron in the prosthetic group of the protein to the ferrous form was observed. The increased affinity between oxygen and the immobilized myoglobin did not favor the release of this solute from the biocarrier.

  13. Preparation and characterization of bioglass/polyvinyl alcohol composite hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Xu Hong [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Wang Yingjun [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Zheng Yudong [College of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Chen Xiaofeng [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Ren Li [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Wu Gang [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 (China); Huang Xiaoshan [College of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2007-06-01

    In order to form firm active fixation with the adjacent bone, a new kind of bioactive composite hydrogel was prepared with polyvinyl alcohol (PVA) and bioglass (BG) through ultrasonic dispersion, heat-high-pressure and freeze/thawed technique. A digital speckle correlation method (DSCM) was utilized to characterize the mechanical properties of the series of BG/PVA composites. Results showed that at different load pressures, the composite hydrogel displayed different displacement and deformation in the V field. Results also showed that an increase of PVA percentage (15-30 wt%) or of bioglass percentage (2-10 wt%) in composite hydrogel could lead to an increase in the elastic compression modulus. Scanning electron microscope results indicated that bioglass was uniformly dispersed in the BG/PVA composite hydrogel. The BG/PVA composite hydrogel shows a promising prospect as a new bionic cartilage implantation material.

  14. Reentrant behaviour in polyvinyl alcohol–borax hydrogels

    Science.gov (United States)

    Lawrence, Mathias B.; Desa, J. A. E.; Aswal, V. K.

    2018-01-01

    Polyvinyl alcohol (PVA) hydrogels, cross-linked with varying concentrations of borax, were studied with small angle neutron scattering (SANS), x-ray diffraction (XRD) and differential thermal analysis (DTA). The SANS data satisfy the Ornstein–Zernike approximation. The hydrogels are modelled as PVA chains bound by borate cross-links. Water occupies the spaces within the three-dimensional hydrogel network. The mesh size ξ indicates reentrant behaviour i.e. at first, ξ increases and later decreases as a function of borax concentration. The behaviour is explained on the basis of the balance between the charged di-diol cross-links and the shielding by free ions in the solvent. XRD and DTA show the molecular size of water in the solvent and the glass transition temperature commensurate with reentrant behaviour.

  15. Synthesis and morphology of polyvinyl alcohol /zinc sulfide nanocomposite

    Science.gov (United States)

    Sirait, M.; Motlan

    2017-07-01

    Polyvinyl alcohol (PVA) nanocomposites have been synthesized. The nanocomposites which prepared by sol-gel method were mixed to various concentrations of PVA using magnetic stirrer bar of 500 rpm at 80°C. After the solvent evaporates, the white suspensions were casted on to a flat metal and the film-like composites formed. Those samples were characterized including tensile for mechanical test follow ISO-527-2 and melting points for thermal analysis using DSC operated at 20°C/min with the temperature range of 30-300°C. The most homogeny and Young modulus samples were obtained at ratio 98:2 w/w % of PVA/ZnS, and the highest melting point were found at ratio 97:3% of PVA/ZnS.

  16. Rheological Properties of Compositions Based on Modified Polyvinyl Alcohol

    Directory of Open Access Journals (Sweden)

    Volodymyr Krasinskyi

    2017-09-01

    By experimental studies have been established that the montmorillonite- polyvinylpyrrolidone mixture significantly affects on viscosity the characteristics of the solution polyvinyl alcohol provided their mixing in the ultrasonic field. Composition of traces of sodium tetraborate in the aqueous solution eminent by the highest rates of viscosity. Also, designed compositions considerable influence pH at the viscosity, particularly compositions obtained in weakly alkaline environment with higher values of relative viscosity than compositions obtained in neutral and acidic environments. Simultaneously, is the best water resistance and mechanical properties of films obtained in an acidic environment. The optimum from the standpoint of durability and water resistance is a composition of PVA:MPM = 12:1 and because, depending on the contents of the MPM and pH characteristics films based on PVA can be adjusted over a wide range, which would expand the scope.

  17. Polyphosphates as Inhibitors for Poly(vinyl Chloride Photodegradation

    Directory of Open Access Journals (Sweden)

    Dina S. Ahmed

    2017-10-01

    Full Text Available Three polyphosphates were used as inhibitors for poly(vinyl chloride (PVC photodegradation. The polyphosphates were added to PVC at a concentration of 0.5% by weight. The PVC films (40 µm thickness were irradiated at room temperature with ultraviolet (UV light for up to 300 h. The changes in PVC films after irradiation were monitored by Fourier transform infrared spectroscopy, weight loss, viscosity-average molecular weight determination, and atomic force microscopy. These changes were very noticeable in the blank PVC films compared to the ones obtained when additives were used. The polyphosphates can inhibit the PVC photodegradation through direct absorption of UV light, interactions with PVC chains, and acting as radical scavengers.

  18. Incidence of cancer among vinyl chloride and polyvinyl chloride workers.

    Science.gov (United States)

    Heldaas, S S; Langård, S L; Andersen, A

    1984-01-01

    The results of a follow up study of the incidence of cancer and the mortality in a cohort of 454 male workers producing vinyl chloride and polyvinyl chloride are presented. The study population was restricted to employees with more than one year's work experience in the study plant between 1950 and 1969 and the cohort was followed up from 1953 to the end of 1979. Twenty three new cases of cancer were observed compared with 20.2 expected; one case of liver angiosarcoma was found. Five cases of lung cancer were found (2.8 expected) and four cases of malignant melanoma of the skin were observed (0.8 expected). The possibility of a causal relationship between exposure to vinyl chloride and the development of malignant melanomas is discussed. PMID:6691932

  19. Polyvinyl alcohol coating of polystyrene inertial confinement fusion targets

    Science.gov (United States)

    Annamalai, P.; Lee, M. C.; Crawley, R. L.; Downs, R. L.

    1985-01-01

    An inertial confinement fusion (ICF) target made of polystyrene is first levitated in an acoustic field. The surface of the target is then etched using an appropriate solution (e.g., cyclohexane) to enhance the wetting characteristics. A specially prepared polyvinyl alcohol solution is atomized using an acoustic atomizer and deposited on the surface of the target. The solution is air dried to form a thin coating (2 microns) on the target (outside diameter of about 350-850 microns). Thicker coatings are obtained by repeated applications of the coating solutions. Preliminary results indicate that uniform coatings may be achievable on the targets with a background surface smoothness in the order of 1000 A.

  20. Cross-linked polyvinyl alcohol films as alkaline battery separators

    Science.gov (United States)

    Sheibley, D. W.; Manzo, M. A.; Gonzalez-Sanabria, O. D.

    1983-01-01

    Cross-linking methods have been investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: (1) PVA-dialdehyde blends post-treated with an acid or acid periodate solution (two-step method) and (2) PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid functionality (one-step method). Laboratory samples of each cross-linked type of film were prepared and evaluated in standard separator screening tests. Then pilot-plant batches of films were prepared and compared to measure differences due to the cross-linking method. The pilot-plant materials were then tested in nickel oxide-zinc cells to compare the two methods with respect to performance characteristics and cycle life. Cell test results are compared with those from tests with Celgard.

  1. Conjugated polymer fluorescence: Interplay of correlations and alternation

    Energy Technology Data Exchange (ETDEWEB)

    Soos, Z.G. [Princeton Univ., NJ (United States). Dept. of Chemistry; Galvao, D.S. [Bell Communications Research, Inc., Red Bank, NJ (United States)]|[Universidade Estadual de Campinas, SP (Brazil). Dept. de Fisica Aplicada; Etemad, S. [Bell Communications Research, Inc., Red Bank, NJ (United States); Kepler, R.G. [Sandia National Labs., Albuquerque, NM (United States)

    1993-12-31

    Conjugated polymers can have high conductivity on doping, large nonlinear optical response in semiconducting state, and be used as LEDs. These polymers include polyactylene, polydiacetylenes, polysilanes, polythiophene, poly-p-phenylenevinylene. Polymer fluorescence is related to the lowest singlet excited state S{sub 1}. Polymer and oligomer data are shown for the excitation energy ratio of the two-photon and one-photon gaps. There is a ratio crossover with increasing e-e correlations in any centrosymmetri chain with an insulating ground state. The {pi}-conjugated polymers present various band gaps at constant correlations, and single-particle gaps can be related to the structure. The nature of the lowest singlet excited state depends sensitively on both correlations and alternation. 22 refs, 2 figs.

  2. Combination effect of melamine polyphosphate and graphene on flame retardant properties of poly(vinyl alcohol)

    Energy Technology Data Exchange (ETDEWEB)

    Huang Guobo, E-mail: huangguobo@tzc.edu.cn [School of Pharmaceutical and Chemical Engineering, Taizhou University, Linhai 317000 (China); Liang Huading; Wang Yong [School of Pharmaceutical and Chemical Engineering, Taizhou University, Linhai 317000 (China); Wang Xu; Gao Jianrong; Fei Zhengdong [State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Zhejiang University of Technology, Hangzhou 310014 (China)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer PVA/graphene/MPP composites were prepared by solvent blending. Black-Right-Pointing-Pointer PVA/graphene systems improved the flame retardancy of the nanocomposites. Black-Right-Pointing-Pointer Flame retardation mechanism was explained by SEM, FT-IR and XPS. - Abstract: A novel flame retardant poly(vinyl alcohol) (PVA)/melamine polyphosphate (MPP)-graphene nanocomposite has been prepared by solvent blending. Results from X-ray diffraction (XRD) and transmission electron microscopy (TEM) suggest that an excellent dispersion of exfoliated graphene and MPP in the PVA matrix was achieved. The thermal and flammability properties of the nanocomposite were investigated using thermogravimetry, cone calorimetry, and flammability tests (UL 94 and LOI). The presence of both MPP and graphene in the polymer matrix led to an enhanced thermal stability and significantly reduced flammability for the nanocomposite. PVA composites filled with 10 wt% MPP and 1 wt% graphene (PVA/G1/MPP10) achieved the LOI value of 29.6 and UL-94 V0 grade. Compared to pure PVA, the peak heat release rate (PHRR) of PVA/G1/MPP10 is reduced by about 60%. Meanwhile, the mechanical properties of PVA/G1/MPP10 composites exhibit almost no deterioration compared with pure PVA. The morphology and composition of residues generated after cone calorimeter tests were investigated by scanning electronic microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The SEM images showed the compact and dense intumescent char jammed with graphene sheets was formed for PVA/G1/MPP10 during combustion. The results of XPS confirmed that carbon content of the char for PVA/G1/MPP10 is increased obviously by the combination effect of the flame retardant MPP and graphene.

  3. Fabrication and properties of irradiation-cross-linked poly(vinyl alcohol)/clay aerogel composites.

    Science.gov (United States)

    Chen, Hong-Bing; Liu, Bo; Huang, Wei; Wang, Jun-Sheng; Zeng, Guang; Wu, Wen-Hao; Schiraldi, David A

    2014-09-24

    Poly(vinyl alcohol) (PVOH)/clay aerogel composites were fabricated by an environmentally friendly freeze-drying of the aqueous precursor suspensions, followed by cross-linking induced by gamma irradiation without chemical additives. The influences of cross-linking conditions, i.e., absorbed dose and polymer loading as well as density on the aerogel structure and properties, were investigated. The absorbed dose of 30 kGy was found to be the optimum dose for fabricating strong PVOH composites; the compressive modulus of an aerogel prepared from an aqueous suspension containing 2 wt % PVOH/8 wt % clay increased 10-fold, and that containing 1 wt % PVOH/9 wt % clay increased 12 times upon cross-linking with a dose of 30 kGy. Increasing the solids concentration led to an increase in the mechanical strength, in accordance with the changes in microstructure from layered structure to network structure. The increase of absorbed dose also led to decreased porous size of the network structure. Cross-linking and the increase of the PVOH lead to decreased thermal stability. The strengthened PVOH/clay aerogels possess very low flammability, as measured by cone calorimetry, with heat, smoke, and volatile products release value decreasing as increasing clay content. The mechanism of flame retardation in these materials was investigated with weight loss, FTIR, WAXD, and SEM of the burned residues. The proposed mechanism is that with decreasing fuel content (increasing clay content), increased heat and mass transport barriers are developed; simultaneously low levels of thermal conductivity are maintained during the burning.

  4. Morphology and thermal studies of zinc sulfide and cadmium sulfide nanoparticles in polyvinyl alcohol matrix

    Energy Technology Data Exchange (ETDEWEB)

    Osuntokun, Jejenija; Ajibade, Peter A., E-mail: pajibade@ufh.ac.za

    2016-09-01

    Zn(II) and Cd(II) metal complexes of 1-cyano-1-carboethoxyethylene-2,2-dithiolato–κS,S’–bis (N,N-dimethylthiourea–κS) have been synthesized and characterized with analytical and spectroscopic techniques. The complexes were thermolysed in hexadecylamine at 200 °C to prepare ZnS and CdS nanoparticles. The nanoparticles were characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), and powder X-ray diffraction (p-XRD). TEM images showed spherically shaped nanoparticles, whose sizes are in the range 4.33–7.21 nm for ZnS and 4.95–7.7 nm CdS respectively and XRD confirmed cubic crystalline phases for the nanoparticles. The optical band gap energy evaluated from the absorption spectra are 2.88 eV (430 nm) and 2.81 eV (440 nm) for the ZnS and CdS nanoparticles respectively. The as-prepared metal sulfide nanoparticles were further incorporated into polyvinyl alcohol (PVA) to give ZnS/PVA and CdS/PVA composites. The polymer nanocomposites were studied to investigate their morphology and thermal properties relative to the pure PVA. XRD diffractions indicated that the crystalline phases of the nanoparticles and the sizes in PVA matrices remained unaltered. Infra-red spectra studies revealed interactions between the PVA and the metal sulfide nanoparticles and TGA studies show that the ZnS/PVA and CdS/PVA nanocomposites exhibit better thermal stability than the pure PVA.

  5. Reorientation of Magnetic Graphene Oxide Nanosheets in Crosslinked Quaternized Polyvinyl Alcohol as Effective Solid Electrolyte

    Directory of Open Access Journals (Sweden)

    Jia-Shuin Lin

    2016-11-01

    Full Text Available This work aims to clarify the effect of magnetic graphene oxide (GO reorientation in a polymer matrix on the ionic conduction and methanol barrier properties of nanocomposite membrane electrolytes. Magnetic iron oxide (Fe3O4 nanoparticles were prepared and dispersed on GO nanosheets (GO-Fe3O4. The magnetic GO-Fe3O4 was imbedded into a quaternized polyvinyl alcohol (QPVA matrix and crosslinked (CL- with glutaraldehyde (GA to obtain a polymeric nanocomposite. A magnetic field was applied in the through-plane direction during the drying and film formation steps. The CL-QPVA/GO-Fe3O4 nanocomposite membranes were doped with an alkali to obtain hydroxide-conducting electrolytes for direct methanol alkaline fuel cell (DMAFC applications. The magnetic field-reoriented CL-QPVA/GO-Fe3O4 electrolyte demonstrated higher conductivity and lower methanol permeability than the unoriented CL-QPVA/GO-Fe3O4 membrane or the CL-QPVA film. The reoriented CL-QPVA/GO-Fe3O4 nanocomposite was used as the electrolyte in a DMAFC and resulted in a maximum power density of 55.4 mW·cm−2 at 60 °C, which is 73.7% higher than that of the composite without the magnetic field treatment (31.9 mW·cm−2. In contrast, the DMAFC using the CL-QPVA electrolyte generated only 22.4 mW·cm−2. This research proved the surprising benefits of magnetic-field-assisted orientation of GO-Fe3O4 in facilitating the ion conduction of a polymeric electrolyte.

  6. Broader Understanding of Multiple Component Dynamic Processes in Miscible Polymer/Polymer Blends

    Science.gov (United States)

    Sharma, Ravi; Yang, Hengxi; Green, Peter

    Utilizing two different experimental techniques, isothermal frequency sweeps and isochronal temperature sweeps, in broadband dielectric spectroscopy can allow for the identification of multiple processes derived from the same relaxation mechanism in certain polymer/polymer blends. A study of poly(vinyl methyl ether) (PVME) in bulk, miscible blends with polystyrene (PS) gives evidence of two separate relaxation processes associated exclusively with the segmental dynamics of PVME; the α0 process from the temperature sweep, related to average segmental dynamics, and the α' process from the frequency sweep, related to relaxations confined within ``frozen'' domains. The appearance of multiple processes is driven by compositional heterogeneity, mainly chain connectivity and concentration fluctuation effects. Analysis of the breadth and intensity of the dielectric loss curves gives insight into the structure and thermodynamics of the blend, which in turn can explain temperature and composition dependent dynamic trends. These results are contrasted with other miscible blend systems, polyisoprene (PI)/poly(4-tert-butylstyrene) (P4tBS) and polyisoprene (PI)/polyvinyl ether (PVE).

  7. Electrooptic Kerr effect of porphyrin H-aggregates in polymer films: Polymer specific spectral blue shift

    Science.gov (United States)

    Suzuki, Masaya; Nakata, Kazuaki; Kuroda, Reiko; Kobayashi, Takayoshi; Tokunaga, Eiji

    2016-05-01

    J- and H-aggregates of porphyrin molecules (TPPS4) in spin-coated polymer films have been studied by electroabsorption and circular dichroism (CD) spectroscopy. A spectral blue shift of the H-band due to the electrooptic Kerr effect was observed for the first time. This occurs only for a polyvinylpyrrolidone (PVP) film, with negligibly small spectral shift observed in polyvinyl alcohol (PVA), polyvinyl sulfate (PVS), and polyacrylic acid (PAA) films, in contrast to the red shift of the J-band which is commonly observed for any host polymers. Accordingly, the CD activity in both of J- and H-bands is more enhanced in PVP films than in PVA films. The mechanism of the blue and red shifts of the respective H- and J-bands is discussed by invoking a helical structure in micro-aggregates, which is compatible with the CD spectra, based on the molecular rearrangement model. It is proved that blue- and red-shifts occur evenly to cancel each other in the H-band if a simple helical structure is assumed, in good agreement with no spectral shifts in the H-band in PVA, PVS, and PAA films.

  8. Polymers for delivering peptides and proteins.

    Science.gov (United States)

    Burnham, N L

    1994-01-15

    The use of polymers for delivering peptide and protein drugs is described. Soluble-polymer technology attempts to bind a polymer to all sites on therapeutic protein molecules that cause the body to recognize the molecules as foreign. Goals include a stable linkage, water solubility, low immunogenicity, prolonged half-life, and intact biological activity. Polyethylene glycol (PEG)-adenosine deaminase (ADA), or pegademase bovine, has FDA-approved labeling as replacement therapy for ADA deficiency in patients with severe combined immunodeficiency disease who are not suitable candidates for bone marrow transplantation. Pegademase bovine reverses the toxic accumulation of adenosine and deoxyadenosine in adenosine deaminase-deficient cells, restoring the immune system. PEG-asparaginase (pegaspargase) has shown promise in patients with acute lymphocytic leukemia; allergic reactions have been minimal. Animal studies suggest that superoxide dismutase has potential use in conditions in which the body's ability to remove oxygen free radicals is reduced, such as burns and myocardial infarction; coupling with PEG may greatly increase the protein's half-life. Other PEG-conjugated proteins under investigation include PEG-catalase, PEG-uricase, PEG-honeybee venom, PEG-hemoglobin, and PEG-modified ragweed pollen extract. Dextran, albumin, DL-amino acids, and polyvinyl pyrrolidone have also been studied as protein carriers; most of the products created thus far have not shown much promise. The coupling of polymers to proteins has yielded protein drugs with intact biological activity and reduced immunogenicity, but much remains to be learned about this technology.

  9. A scalable fabrication process of polymer microneedles.

    Science.gov (United States)

    Yang, Sixing; Feng, Yan; Zhang, Lijun; Chen, Nixiang; Yuan, Weien; Jin, Tuo

    2012-01-01

    While polymer microneedles may easily be fabricated by casting a solution in a mold, either centrifugation or vacuumizing is needed to pull the viscous polymer solution into the microholes of the mold. We report a novel process to fabricate polymer microneedles with a one-sided vacuum using a ceramic mold that is breathable but water impermeable. A polymer solution containing polyvinyl alcohol and polysaccharide was cast in a ceramic mold and then pulled into the microholes by a vacuum applied to the opposite side of the mold. After cross-linking and solidification through freeze-thawing, the microneedle patch was detached from the mold and transferred with a specially designed instrument for the drying process, during which the patch shrank evenly to form an array of regular and uniform needles without deformation. Moreover, the shrinkage of the patches helped to reduce the needles' size to ease microfabrication of the male mold. The dried microneedle patches were finally punched to the desired sizes to achieve various properties, including sufficient strength to penetrate skin, microneedles-absorbed water-swelling ratios, and drug-release kinetics. The results showed that the microneedles were strong enough to penetrate pigskin and that their performance was satisfactory in terms of swelling and drug release.

  10. Mediating conducting polymer growth within hydrogels by controlling nucleation

    Directory of Open Access Journals (Sweden)

    A. J. Patton

    2015-01-01

    Full Text Available This study examines the efficacy of primary and secondary nucleation for electrochemical polymerisation of conductive polymers within poly(vinyl alcohol methacrylate hydrogels. The two methods of nucleation investigated were a primary heterogeneous mechanism via introduction of conductive bulk metallic glass (Mg64Zn30Ca5Na1 particles and a secondary mechanism via introduction of “pre-polymerised” conducting polymer within the hydrogel (PEDOT:PSS. Evidence of nucleation was not seen in the bulk metallic glass loaded gels, however, the PEDOT:PSS loaded gels produced charge storage capacities over 15 mC/cm2 when sufficient polymer was loaded. These studies support the hypothesis that secondary nucleation is an efficient approach to producing stand-alone conducting hydrogels.

  11. Polymer brushes on planar TiO2 substrates.

    Science.gov (United States)

    Yang, Jiming; Hou, Liman; Xu, Bin; Zhang, Ning; Liang, Yongjiu; Tian, Wenjing; Dong, Dewen

    2014-07-01

    A facile and universal method is presented for the preparation of polymer brushes on amorphous TiO2 film. Homogeneous and stable poly(methyl methacrylate), polystyrene, poly(4-vinylpyridine), and poly(N-vinyl imidazole) (PNVI) brushes up to 550 nm are directly created onto TiO2 via UV-induced photopolymerization of corresponding monomers. Kinetic studies reveal a linear increase in thickness with the polymerization time. Characterization of the resulting polymer brushes by FTIR spectroscopy, X-ray photoelectron spectroscopy, contact angle, and atomic force microscopy (AFM) indicates an efficient UV-grafting reaction. Finally, we have demonstrated the possibility in converting the PNVI brushes to poly(vinyl imidazolium bromide), i.e., poly(ionic liquid) brushes by polymer-analogous reactions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Synthesis and study of conjugated polymers containing Di- or Triphenylamine

    Energy Technology Data Exchange (ETDEWEB)

    Sukwattanasinitt, M.

    1996-06-21

    This thesis consists of two separate parts. The first part addresses the synthesis and study of conjugated polymers containing di- or triphenylamine. Two types of polymers: linear polymers and dendrimers, were synthesized. The polymers were characterized by NMR, IR, UV, GPC, TGA and DSC. Electronic and optical properties of the polymers were studied through the conductivity measurements and excitation- emission spectra. the second part of this thesis deals with a reaction of electron-rich acetylenes with TCNE. The discovery of the reaction from charge transfer complex studies and the investigation of this reaction on various electron-rich acetylenes are presented.

  13. Polyvinyl chloride as a multimodal tissue-mimicking material with tuned mechanical and medical imaging properties.

    Science.gov (United States)

    Li, Weisi; Belmont, Barry; Greve, Joan M; Manders, Adam B; Downey, Brian C; Zhang, Xi; Xu, Zhen; Guo, Dongming; Shih, Albert

    2016-10-01

    The mechanical and imaging properties of polyvinyl chloride (PVC) can be adjusted to meet the needs of researchers as a tissue-mimicking material. For instance, the hardness can be adjusted by changing the ratio of softener to PVC polymer, mineral oil can be added for lubrication in needle insertion, and glass beads can be added to scatter acoustic energy similar to biological tissue. Through this research, the authors sought to develop a regression model to design formulations of PVC with targeted mechanical and multimodal medical imaging properties. The design of experiment was conducted by varying three factors-(1) the ratio of softener to PVC polymer, (2) the mass fraction of mineral oil, and (3) the mass fraction of glass beads-and measuring the mechanical properties (elastic modulus, hardness, viscoelastic relaxation time constant, and needle insertion friction force) and the medical imaging properties [speed of sound, acoustic attenuation coefficient, magnetic resonance imaging time constants T1 and T2, and the transmittance of the visible light at wavelengths of 695 nm (Tλ695) and 532 nm (Tλ532)] on twelve soft PVC samples. A regression model was built to describe the relationship between the mechanical and medical imaging properties and the values of the three composition factors of PVC. The model was validated by testing the properties of a PVC sample with a formulation distinct from the twelve samples. The tested soft PVC had elastic moduli from 6 to 45 kPa, hardnesses from 5 to 50 Shore OOO-S, viscoelastic stress relaxation time constants from 114.1 to 191.9 s, friction forces of 18 gauge needle insertion from 0.005 to 0.086 N/mm, speeds of sound from 1393 to 1407 m/s, acoustic attenuation coefficients from 0.38 to 0.61 (dB/cm)/MHz, T1 relaxation times from 426.3 to 450.2 ms, T2 relaxation times from 21.5 to 28.4 ms, Tλ695 from 46.8% to 92.6%, and Tλ532 from 41.1% to 86.3%. Statistically significant factors of each property were identified. The

  14. Determination of gelation doses of gamma-irradiated hydrophilic polymers by different methods

    Energy Technology Data Exchange (ETDEWEB)

    Yigit, Fatma; Tekin, Niket; Erkan, Sevin; Gueven, Olgun (Hacettepe Univ., Ankara (Turkey). Dept. of Chemistry)

    1994-04-01

    Poly(acrylic acid) and poly(vinyl pyrrolidone) are hydrophilic polymers. Poly(acrylic acid) is a polyelectrolyte which ionizes in water to produce an electrically conducting medium. In this study, it has been shown that the gelation dose of poly(acrylic acid) can be determined by conductimetric and titrimetric methods with NaOH and measuring pH of aqueous solution of [gamma]-irradiated polymer. In order to develop new, simpler and rapid methods for the determination of gelation dose of PVP, its complexation with gallic acid in dilute aqueous solution has been used. The complex formation between gallic acid and irradiated PVP in aqueous solutions is followed by UV-vis spectroscopy. The reliability of the dose value found, 120 kGy for poly(acrylic acid) and 140 kGy for poly(vinyl pyrrolidone), are also verified by viscometric and solubility measurements. (author).

  15. Strength and deformation characteristics of polymer blend films obtained from water systems

    Science.gov (United States)

    Jelinska, N.; Kalnins, M.

    2011-11-01

    The relationship between the tensile strength and deformation characteristics, composition, and structural organization of films obtained by casting of two-component water-based system blends — a solution of the rigid partly crystalline polymer polyvinyl alcohol (PVA) and an emulsion of the compliant amorphous polymer polyvinyl acetate (PVAc) — has been investigated. The aim of this investigation was to ascertain the possibility of obtaining film materials with increased deformability based on the biodegradable PVA. The composition dependences of the initial modulus of elasticity, the maximum stress, yield stress, the ultimate strength, the ultimate strain, and of the unit work of fracture and other characteristics of films have been analyzed. An analysis of the tensile true stress-strain curves of systems with volume fractions of PVA less than 0.5 points to their considerable orientation strengthening upon tension.

  16. Polymer flooding

    Energy Technology Data Exchange (ETDEWEB)

    Littmann, W.

    1988-01-01

    This book covers all aspects of polymer flooding, an enhanced oil recovery method using water soluble polymers to increase the viscosity of flood water, for the displacement of crude oil from porous reservoir rocks. Although this method is becoming increasingly important, there is very little literature available for the engineer wishing to embark on such a project. In the past, polymer flooding was mainly the subject of research. The results of this research are spread over a vast number of single publications, making it difficult for someone who has not kept up-to-date with developments during the last 10-15 years to judge the suitability of polymer flooding to a particular field case. This book tries to fill that gap. An indispensable book for reservoir engineers, production engineers and lab. technicians within the petroleum industry.

  17. 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)

  18. Effects of Preparation Methods of Organoclays with Polyvinyl Alcohol in their Compatibility with HDPE. Thermal Stability

    OpenAIRE

    Carrera, María Celeste; Erdmann, Eleonora; Destefanis, Hugo Alberto

    2016-01-01

    In this paper, the effect of polyvinyl alcohol addition on organoclay obtained by in situ polymerization and subsequent alcoholysis of polyvinyl acetate is studied. The incorporation of the monomer is carried out following two procedures. The first is the incorporation of the monomer by direct contact between the monomer and the organoclay. The second procedure involves a first step of impregnating the organoclay with propyl alcohol and the subsequent incorporation of the monomer. Both proced...

  19. Sorption of ions Pb2+ by cryogels on the basis of polyvinyl alcohol and bentonite clay

    Directory of Open Access Journals (Sweden)

    А. Seralin

    2012-03-01

    Full Text Available Cryogels on the basis of polyvinyl alcohol and bentonite clay were synthesized. Influences of factors of environment (pH, temperature on properties of composites and them sorption ability were considered. In given article it is resulted sorption kinetics of lead ions on bentonite clay, and also composite cryogel on the basis of polyvinyl alcohol and bentonite clay. It was established that composite cryogels shows much bigger sorption ability.

  20. Separation and analysis of low molecular weight plasticizers in poly(vinyl chloride) tubes

    DEFF Research Database (Denmark)

    Wang, Qian; Storm, Birgit Kjærside

    2005-01-01

    The separation of plasticizers in polyvinyl chloride (PVC) used in medical applications was carried out in different solvents and compared by studying the remaining PVC after separation using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravime......The separation of plasticizers in polyvinyl chloride (PVC) used in medical applications was carried out in different solvents and compared by studying the remaining PVC after separation using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC...

  1. Effect of host polymer blends to phosphorescence emission | Alias ...

    African Journals Online (AJOL)

    ... pulsed UV excitation source of Xenon lamp. The results shows that there were changing in the phosphorescence emission and life time with difference host polymer. The explanation of phosphorescence emission has been supported by ZINDO calculation. Keywords: luminescence; phosphorescence, polymer blend ...

  2. Electrically Conducting Polymer-Copper Sulphide Composite Films, Preparation by Treatment of Polymer-Copper (2) Acetate Composites with Hydrogen Sulfide

    Science.gov (United States)

    Yamamoto, Takakazu; Kamigaki, Takahira; Kubota, Etsuo

    1988-01-01

    Polymer copper sulfide composite films were prepared by treatment of polymer poly(vinyl chloride), poly(acrylonitrile), copolymer of vinyl chloride and vinyl acetate (90:10), and ABS resin copper (2) acetate composites with hydrogen sulfide. The films showed electrical conductivity higher than 0.015 S/cm when they contained more than 20 wt percent of copper sulfide. A poly(acrylonitrile)-copper sulfide composite film containing 40 to 50 wt percent of copper sulfide showed electrical conductivity of 10 to 150.0 S/cm and had relatively high mechanical strength to be used in practical purposes.

  3. Electrospun of polymer/bioceramic nanocomposite as a new soft tissue for biomedical applications

    OpenAIRE

    Heydary, Hamid Amiri; Karamian, Ebrahim; Poorazizi, Elahe; Heydaripour, Jalil; Khandan, Amirsalar

    2015-01-01

    Iranian Gum Tragacanth (IGT) is among the most natural polymers which has interesting properties such as nontoxic nature, biodegradability and high resistance to bacterial attacks making it applicable for tissue scaffolds, protective clothing, and wound healing. In the current work, polyvinyl alcohol (PVA)/IGT nanocomposite fibre is prepared by using the electrospinning (ELS) technique in an aqueous solution with different volume ratios of 60/40, 70/30, 80/20, and 90/10. To enhance the chemic...

  4. In-situ fabrication of polymer/metal nanocomposite films using a mid-infrared laser

    Science.gov (United States)

    Nakajima, Takashi

    2017-09-01

    We demonstrate a very rapid in-situ fabrication of polymer/metal nanocomposite films. Using a CO2 laser at 10.6 μm, Ag-PVA (polyvinyl alcohol) nanocomposite films are successfully fabricated on a glass substrate within 10 seconds, which is the most rapid method among any known fabrication methods. The fabricated films are characterized using the optical absorption, atomic force microscopy, and x-ray diffraction measurements.

  5. Interface profile studies in immiscible and partially miscible binary polymer blends from free volume measurement

    Science.gov (United States)

    Ramya, P.; Meghala, D.; Pasang, T.; Raj, J. M.; Ranganathaiah, C.; Williams, J. F.

    2013-06-01

    The diffused interface widths in an immiscible and a partially miscible polymer blend namely Polyvinyl chloride/Ethylene vinyl acetate (PVC/EVA) and Polystyrene/Polymethylmethacrylate (PS/PMMA) are experimentally measured and reported here. A new empirical relation found between hydrodynamic interaction parameter α derived from free volume data and the Flory-Huggins interaction parameter χ is used to construct density profile across the interface to derive the interface width in above two binary blends.

  6. Influence of humidity on the phase behavior of API/polymer formulations.

    Science.gov (United States)

    Prudic, Anke; Ji, Yuanhui; Luebbert, Christian; Sadowski, Gabriele

    2015-08-01

    Amorphous formulations of APIs in polymers tend to absorb water from the atmosphere. This absorption of water can induce API recrystallization, leading to reduced long-term stability during storage. In this work, the phase behavior of different formulations was investigated as a function of relative humidity. Indomethacin and naproxen were chosen as model APIs and poly(vinyl pyrrolidone) (PVP) and poly(vinyl pyrrolidone-co-vinyl acetate) (PVPVA64) as excipients. The formulations were prepared by spray drying. The water sorption in pure polymers and in formulations was measured at 25°C and at different values of relative humidity (RH=25%, 50% and 75%). Most water was absorbed in PVP-containing systems, and water sorption was decreasing with increasing API content. These trends could also be predicted in good agreement with the experimental data using the thermodynamic model PC-SAFT. Furthermore, the effect of absorbed water on API solubility in the polymer and on the glass-transition temperature of the formulations was predicted with PC-SAFT and the Gordon-Taylor equation, respectively. The absorbed water was found to significantly decrease the API solubility in the polymer as well as the glass-transition temperature of the formulation. Based on a quantitative modeling of the API/polymer phase diagrams as a function of relative humidity, appropriate API/polymer compositions can now be selected to ensure long-term stable amorphous formulations at given storage conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. The adsorption of methyl methacrylate and vinyl acetate polymers on α-quartz surface: A molecular dynamics study

    Science.gov (United States)

    Yan, Lijing; Yang, Yan; Jiang, Hui; Zhang, Bingjian; Zhang, Hui

    2016-01-01

    The molecular dynamics simulation was used to investigate the adsorption of polymethyl methacrylate (PMMA) and polyvinyl acetate (PVA), the commonly used surface coating materials, on α-quartz surface. The objective is to understand the interactions between quartz surface and polymers. The results clearly show adsorption of both polymers onto the quartz surface. Carbonyl group plays a significant role in the adsorption process. The adsorption energies of PMMA and PVA on α-quartz surface did not show significant difference, however, more hydrogen bonds were observed on the PVA/quartz system than PMMA/quartz. These observations might offer some insights on the polymer-quartz adhesion and its failure mechanism.

  8. Excitations in organic solids

    CERN Document Server

    Agranovich, Vladimir M

    2009-01-01

    During the last decade our expertise in nanotechnology has advanced considerably. The possibility of incorporating in the same nanostructure different organic and inorganic materials has opened up a promising field of research, and has greatly increased the interest in the study of properties of excitations in organic materials. In this book not only the fundamentals of Frenkel exciton and polariton theory are described, but also the electronic excitations and electronic energytransfers in quantum wells, quantum wires and quantum dots, at surfaces, at interfaces, in thin films, in multilayers,

  9. Excitation Methods for Bridge Structures

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, C.R.; Duffy, T.A.; Cornwell, P.J.; Doebling, S.W.

    1999-02-08

    This paper summarizes the various methods that have been used to excited bridge structures during dynamic testing. The excitation methods fall into the general categories of ambient excitation methods and measured-input excitation methods. During ambient excitation the input to the bridge is not directly measured. In contrast, as the category label implies, measured-input excitations are usually applied at a single location where the force input to the structure can be monitored. Issues associated with using these various types of measurements are discussed along with a general description of the various excitation methods.

  10. Procurement model for copper and polymer electrical products

    Directory of Open Access Journals (Sweden)

    S. Sremac

    2013-10-01

    Full Text Available Procurement model for copper and polymer electrical products. Electrical cable structure (wire, insulation, filling and mantle is in accordance with the technical specifications of individual cable components in terms of the incorporated materials. Materials used in cable manufacture are copper, aluminum, rubber and polyvinyl chloride. One of the key issues in managing the flow of goods pertains to the timing of procurement. The combination of the two concepts can take advantage of individual strengths of fuzzy logic and neural networks in hybrid systems of homogeneous structure. The model has high practical significance, as, with minor modifications, it can be applied in any enterprise responsible for managing the goods flows.

  11. The kinetics of photochemical processes in polymer-salt systems

    Science.gov (United States)

    Ostroushko, A. A.; Sennikov, M. Yu.

    2009-01-01

    The kinetics of photochemical reactions in aqueous polymer-salt systems containing ammonium heptamolybdate, dodecatungstate, or metavanadate and polyvinyl alcohol or polyvinylpyrrolidone was studied by measurements of photoinduced electrode potential difference. The rate of primary accumulation of reduced d metal forms was evaluated for different systems. Possible reasons for complex oscillatory processes in the systems were analyzed. Comparative data were obtained for compositions containing polyoxometallate shaped like buckyball:(NH4)42[Mo{72/VI}Mo{60/V}O372(HCOO)30(H2O)72] · 30HCOONH4 · 250H2O. UV irradiation of this system caused the oxidation of molybdenum(V).

  12. Positron excitation of neon

    Science.gov (United States)

    Parcell, L. A.; Mceachran, R. P.; Stauffer, A. D.

    1990-01-01

    The differential and total cross section for the excitation of the 3s1P10 and 3p1P1 states of neon by positron impact were calculated using a distorted-wave approximation. The results agree well with experimental conclusions.

  13. Hardness and excitation energy

    Indian Academy of Sciences (India)

    It is shown that the first excitation energy can be given by the Kohn-Sham hardness (i.e. the energy difference of the ground-state lowest unoccupied and highest occupied levels) plus an extra term coming from the partial derivative of the ensemble exchange-correlation energy with respect to the weighting factor in the ...

  14. Excitation of Stellar Pulsations

    DEFF Research Database (Denmark)

    Houdek, G.

    2012-01-01

    In this review I present an overview of our current understanding of the physical mechanisms that are responsible for the excitation of pulsations in stars with surface convection zones. These are typically cooler stars such as the δ Scuti stars, and stars supporting solar-like oscillations....

  15. Tuning the SERS Response with Ag-Au Nanoparticle-Embedded Polymer Thin Film Substrates.

    Science.gov (United States)

    Rao, V Kesava; Radhakrishnan, T P

    2015-06-17

    Development of facile routes to the fabrication of thin film substrates with tunable surface enhanced Raman scattering (SERS) efficiency and identification of the optimal conditions for maximizing the enhancement factor (EF) are significant in terms of both fundamental and application aspects of SERS. In the present work, polymer thin films with embedded bimetallic nanoparticles of Ag-Au are fabricated by a simple two-stage protocol. Ag nanoparticles are formed in the first stage, by the in situ reduction of silver nitrate by the poly(vinyl alcohol) (PVA) film through mild thermal annealing, without any additional reducing agent. In the second stage, aqueous solutions of chloroauric acid spread on the Ag-PVA thin film under ambient conditions, lead to the galvanic displacement of Ag by Au in situ inside the film, and the formation of Ag-Au particles. Evolution of the morphology of the bimetallic nanoparticles into hollow cage structures and the distribution of Au on the nanoparticles are revealed through electron microscopy and energy dispersive X-ray spectroscopy. The localized surface plasmon resonance (LSPR) extinction of the nanocomposite thin film evolves with the Ag-Au composition; theoretical simulation of the extinction spectra provides insight into the observed trends. The Ag-Au-PVA thin films are found to be efficient substrates for SERS. The EF follows the variation of the LSPR extinction vis-à-vis the excitation laser wavelength, but with an offset, and the maximum SERS effect is obtained at very low Au content; experiments with Rhodamine 6G showed EFs on the order of 10(8) and a limit of detection of 0.6 pmol. The present study describes a facile and simple fabrication of a nanocomposite thin film that can be conveniently deployed in SERS investigations, and the utility of the bimetallic system to tune and maximize the EF.

  16. Optical fiber ultrasound transmitter with electrospun carbon nanotube-polymer composite

    Science.gov (United States)

    Poduval, Radhika K.; Noimark, Sacha; Colchester, Richard J.; Macdonald, Thomas J.; Parkin, Ivan P.; Desjardins, Adrien E.; Papakonstantinou, Ioannis

    2017-05-01

    All-optical ultrasound transducers are promising for imaging applications in minimally invasive surgery. In these devices, ultrasound is transmitted and received through laser modulation, and they can be readily miniaturized using optical fibers for light delivery. Here, we report optical ultrasound transmitters fabricated by electrospinning an absorbing polymer composite directly onto the end-face of optical fibers. The composite coating consisting of an aqueous dispersion of multi-walled carbon nanotubes (MWCNTs) in polyvinyl alcohol was directly electrospun onto the cleaved surface of a multimode optical fiber and subsequently dip-coated with polydimethylsiloxane (PDMS). This formed a uniform nanofibrous absorbing mesh over the optical fiber end-face wherein the constituent MWCNTs were aligned preferentially along individual nanofibers. Infiltration of the PDMS through this nanofibrous mesh onto the underlying substrate was observed and the resulting composites exhibited high optical absorption (>97%). Thickness control from 2.3 μm to 41.4 μm was obtained by varying the electrospinning time. Under laser excitation with 11 μJ pulse energy, ultrasound pressures of 1.59 MPa were achieved at 1.5 mm from the coatings. On comparing the electrospun ultrasound transmitters with a dip-coated reference fabricated using the same constituent materials and possessing identical optical absorption, a five-fold increase in the generated pressure and wider bandwidth was observed. The electrospun transmitters exhibited high optical absorption, good elastomer infiltration, and ultrasound generation capability in the range of pressures used for clinical pulse-echo imaging. All-optical ultrasound probes with such transmitters fabricated by electrospinning could be well-suited for incorporation into catheters and needles for diagnostics and therapeutic applications.

  17. Photothermally excited force modulation microscopy for broadband nanomechanical property measurements

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Ryan, E-mail: ryan.wagner@nist.gov; Killgore, Jason P. [Material Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305 (United States)

    2015-11-16

    We demonstrate photothermally excited force modulation microscopy (PTE FMM) for mechanical property characterization across a broad frequency range with an atomic force microscope (AFM). Photothermal excitation allows for an AFM cantilever driving force that varies smoothly as a function of drive frequency, thus avoiding the problem of spurious resonant vibrations that hinder piezoelectric excitation schemes. A complication of PTE FMM is that the sub-resonance cantilever vibration shape is fundamentally different compared to piezoelectric excitation. By directly measuring the vibrational shape of the cantilever, we show that PTE FMM is an accurate nanomechanical characterization method. PTE FMM is a pathway towards the characterization of frequency sensitive specimens such as polymers and biomaterials with frequency range limited only by the resonance frequency of the cantilever and the low frequency limit of the AFM.

  18. Adsorption Characteristics of Polyvinyl Alcohols in Solution on Expanded Graphite

    Directory of Open Access Journals (Sweden)

    Xiu-Yan Pang

    2012-01-01

    Full Text Available Expanded graphite (EG adsorbent was prepared with 50 mesh graphite as raw materials, potassium permanganate as oxidant, and vitriol as intercalation compound. Three kinds of polyvinyl alcohol (PVA with different degree of polymerization (DP in aqueous solution were used as adsorbates. We have studied the influence of initial PVA concentration, temperature and ionic strength on adsorption capacity. Langmuir constants and Gibbs free energy change (⊿G° were calculated according to experimental data respectively. Thermodynamic analysis indicates the equilibrium adsorbance of PVA on EG increase with the rise of SO42– concentration. Adsorption isotherms of PVA with different degree of polymerization are all types and we deduce PVA molecules lie flat on EG surface. Adsorption processes are all spontaneous. Kinetic studies show that the kinetic data can be described by pseudo second-order kinetic model. Second-order rate constants and the initial adsorption rate rise with the increasing of temperature and half-adsorption time decreases with the increasing of temperature. The adsorption activation energy of each PVA is less than 20 kJ•mol−1, physical adsorption is the major mode of the overall adsorption process.

  19. Evaluation of Phenylephrine Stability in Polyvinyl Chloride Bags

    Science.gov (United States)

    Oldland, Alan R.; Kiser, Tyree H.

    2014-01-01

    Abstract Purpose: Phenylephrine hydrochloride (HCl) is commonly used to maintain adequate blood pressure during shock and shocklike states. Phenylephrine is prepared in concentrated stock vials that require further dilution prior to administration. This study evaluated the physical and chemical stability of phenylephrine in extemporaneously prepared polyvinyl chloride (PVC) bags. Methods: Phenylephrine HCl 10 mg/mL solution was diluted with 0.9% sodium chloride for injection to final concentrations of 200 µg/mL and 400 µg/mL and stored at room temperature (23°C-25°C) exposed to fluorescent light. Stability of phenylephrine HCl was evaluated by high-performance liquid chromatography on days 0, 7, 14, 21, 30, 45, and 60. Results: Phenylephrine HCl 200 and 400 µg/mL solutions in PVC bags were physically stable during the entire 60-day study period. Phenylephrine HCl retained > 95% of the original concentration. Conclusion: Phenylephrine HCl diluted to 200 or 400 µg/mL with 0.9% sodium chloride for injection is both physically and chemically stable for a period of 60 days with ≤5% degradation when stored at room temperature and exposed to fluorescent lighting. PMID:24958958

  20. Poly(vinyl alcohol) gels as photoacoustic breast phantoms revisited.

    Science.gov (United States)

    Xia, Wenfeng; Piras, Daniele; Heijblom, Michelle; Steenbergen, Wiendelt; van Leeuwen, Ton G; Manohar, Srirang

    2011-07-01

    A popular phantom in photoacoustic imaging is poly(vinyl alcohol) (PVA) hydrogel fabricated by freezing and thawing (F-T) aqueous solutions of PVA. The material possesses acoustic and optical properties similar to those of tissue. Earlier work characterized PVA gels in small test specimens where temperature distributions during F-T are relatively homogeneous. In this work, in breast-sized samples we observed substantial temperature differences between the shallow regions and the interior during the F-T procedure. We investigated whether spatial variations were also present in the acoustic and optical properties. The speed of sound, acoustic attenuation, and optical reduced scattering coefficients were measured on specimens sampled at various locations in a large phantom. In general, the properties matched values quoted for breast tissue. But while acoustic properties were relatively homogeneous, the reduced scattering was substantially different at the surface compared with the interior. We correlated these variations with gel microstructure inspected using scanning electron microscopy. Interestingly, the phantom's reduced scattering spatial distribution matches the optical properties of the standard two-layer breast model used in x ray dosimetry. We conclude that large PVA samples prepared using the standard recipe make excellent breast tissue phantoms.

  1. Poly(vinyl alcohol) gels as photoacoustic breast phantoms revisited

    Science.gov (United States)

    Xia, Wenfeng; Piras, Daniele; Heijblom, Michelle; Steenbergen, Wiendelt; van Leeuwen, Ton G.; Manohar, Srirang

    2011-07-01

    A popular phantom in photoacoustic imaging is poly(vinyl alcohol) (PVA) hydrogel fabricated by freezing and thawing (F-T) aqueous solutions of PVA. The material possesses acoustic and optical properties similar to those of tissue. Earlier work characterized PVA gels in small test specimens where temperature distributions during F-T are relatively homogeneous. In this work, in breast-sized samples we observed substantial temperature differences between the shallow regions and the interior during the F-T procedure. We investigated whether spatial variations were also present in the acoustic and optical properties. The speed of sound, acoustic attenuation, and optical reduced scattering coefficients were measured on specimens sampled at various locations in a large phantom. In general, the properties matched values quoted for breast tissue. But while acoustic properties were relatively homogeneous, the reduced scattering was substantially different at the surface compared with the interior. We correlated these variations with gel microstructure inspected using scanning electron microscopy. Interestingly, the phantom's reduced scattering spatial distribution matches the optical properties of the standard two-layer breast model used in x ray dosimetry. We conclude that large PVA samples prepared using the standard recipe make excellent breast tissue phantoms.

  2. Time domain NMR evaluation of poly(vinyl alcohol xerogels

    Directory of Open Access Journals (Sweden)

    Elton Jorge da Rocha Rodrigues

    Full Text Available Abstract Poly(vinyl alcohol (PVA-based chemically cross-linked xerogels, both neat and loaded with nanoparticulate hydrophilic silica (SiO2, were obtained and characterized mainly through time domain NMR experiments (TD-NMR. Fourier-transform infrared (FT-IR and wide angle X-ray diffraction (WAXD analyses were employed as secondary methods. TD-NMR, through the interpretation of the spin-lattice relaxation constant values and related information, showed both cross-linking and nanoparticle influences on PVA matrix. SiO2 does not interact chemically with the PVA chains, but has effect on its molecular mobility, as investigated via TD-NMR. Apparent energy of activation, spin-lattice time constant and size of spin domains in the sample have almost linear dependence with the degree of cross-linking of the PVA and are affected by the addition of SiO2. These three parameters were derived from a single set of TD-NMR experiments, which demonstrates the versatility of the technique for characterization of inorganic-organic hybrid xerogels, an important class of materials.

  3. Time domain NMR evaluation of poly(vinyl alcohol) xerogels

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Elton Jorge da Rocha; Cavalcante, Maxwell de Paula; Tavares, Maria Ines Bruno, E-mail: mibt@ima.ufrj.br [Universidade Federal do Rio de Janeiro (IMA/UFRJ), Rio de Janeiro, RJ (Brazil). Centro de Tecnologia. Instituto de Macromoleculas Professora Eloisa Mano

    2016-05-15

    Poly(vinyl alcohol) (PVA)-based chemically cross-linked xerogels, both neat and loaded with nanoparticulate hydrophilic silica (SiO{sub 2}), were obtained and characterized mainly through time domain NMR experiments (TD-NMR). Fourier-transform infrared (FT-IR) and wide angle X-ray diffraction (WAXD) analyses were employed as secondary methods. TD-NMR, through the interpretation of the spin-lattice relaxation constant values and related information, showed both cross-linking and nanoparticle influences on PVA matrix. SiO{sub 2} does not interact chemically with the PVA chains, but has effect on its molecular mobility, as investigated via TD-NMR. Apparent energy of activation, spin-lattice time constant and size of spin domains in the sample have almost linear dependence with the degree of cross-linking of the PVA and are affected by the addition of SiO{sub 2}. These three parameters were derived from a single set of TD-NMR experiments, which demonstrates the versatility of the technique for characterization of inorganic-organic hybrid xerogels, an important class of materials. (author)

  4. Crosslinked poly(vinyl alcohol)/sulfonated poly(ether ether ketone) blend membranes for fuel cell applications - Surface energy characteristics and proton conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Kanakasabai, P.; Vijay, P.; Deshpande, Abhijit P.; Varughese, Susy [Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India)

    2011-02-01

    Ionic polymers, their blends and composites are considered potential candidates for application as electrolytes in fuel cells. While developing new materials for membranes, it is important to understand the interactions of these electrolytic materials with electrodes/catalysts and with reactants/products. Some of these interactions can be understood by estimating the surface energy and wettability of the membrane materials. In this work, polyvinyl alcohol with varying degrees of sulfonation and its blend with sulfonated poly(ether ether ketone) are prepared and studied for their wettability characteristics using goniometry. The surface energy and its components are estimated using different approaches and compared. Properties such as the ion-exchange capacity, the proton conductivity and the water sorption/desorption behaviour are also investigated to understand the relationship with wettability and surface energy and its components. Among the different methods, the van Oss acid-base and the modified Berthelot approaches yield comparable estimates for the total surface energy. (author)

  5. Palladium Nanoparticles Immobilized on Poly(vinyl chloride-Supported Pyridinium as an Efficient and Recyclable Catalyst for Suzuki-Miyaura Cross-Coupling Reaction

    Directory of Open Access Journals (Sweden)

    Bo Zhou

    2011-01-01

    Full Text Available The palladium nanoparticles immobilized on the polymeric surface of poly(vinyl chloride-supported pyridinium (PVC-Py-Pd0 were achieved by a simple procedure by applying the corresponding functionalized polymer and palladium chloride in ethanol solution. The as-prepared catalyst (PVC-Py-Pd0 was found to be air and moisture stable and exhibits significant catalytic activity for Suzuki-Miyaura cross-coupling reaction of various aryl halides and phenylboronic acid under milder operating conditions. The procedure presented here showed several merits such as short reaction time, simple experimental and isolated procedure and excellent yields of products. Furthermore, the catalyst can be easily recovered and reused for at least six times with consistent activities.

  6. Crosslinked poly(vinyl alcohol)/sulfonated poly(ether ether ketone) blend membranes for fuel cell applications-Surface energy characteristics and proton conductivity

    Science.gov (United States)

    Kanakasabai, P.; Vijay, P.; Deshpande, Abhijit P.; Varughese, Susy

    Ionic polymers, their blends and composites are considered potential candidates for application as electrolytes in fuel cells. While developing new materials for membranes, it is important to understand the interactions of these electrolytic materials with electrodes/catalysts and with reactants/products. Some of these interactions can be understood by estimating the surface energy and wettability of the membrane materials. In this work, polyvinyl alcohol with varying degrees of sulfonation and its blend with sulfonated poly(ether ether ketone) are prepared and studied for their wettability characteristics using goniometry. The surface energy and its components are estimated using different approaches and compared. Properties such as the ion-exchange capacity, the proton conductivity and the water sorption/desorption behaviour are also investigated to understand the relationship with wettability and surface energy and its components. Among the different methods, the van Oss acid-base and the modified Berthelot approaches yield comparable estimates for the total surface energy.

  7. 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.

  8. Area Selective Polymer Brush Deposition.

    Science.gov (United States)

    Cummins, Cian; Shaw, Matthew T; Morris, Michael A

    2017-08-01

    Polymer brush films with chemical functionality to attach to site specific substrate areas are introduced for area selective deposition (ASD) application. It is demonstrated that polymer brushes with chemically defined end sites can be selectively bound to copper-specific regions of patterned copper/silica (Cu/SiO2 ) substrates. The process described overcomes various limitations of currently used technology including cost, complexity, and throughput, with potential implications for future electronic devices and nanomanufacturing. A comparative study of amine-terminated polystyrene and amine-terminated poly-2-vinyl pyridine polymer brushes (i.e., PS-NH2 and P2VP-NH2 ) with similar molecular weights display contrasting behavior on patterned Cu/SiO2 line features. Further, a thiol terminated poly-2-vinyl pyridine polymer brush (i.e., P2VP-SH) is investigated as a direct spin-on process to fabricate a metal oxide layer atop Cu areas only. The results presented here detail a novel methodology and open a new exciting process for ASD practices that can facilitate the precise deposition of dense metal, semiconductor, or dielectric films. We also discuss the applicability of polymer brushes to ASD uses going forward. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Application of polyvinyl alcohol hydrogel membrane as anti-adhesive interposition after spinal surgery.

    Science.gov (United States)

    Hiraizumi, Y; Transfeldt, E E; Fujimaki, E; Nambu, M

    1995-11-01

    Three inflammatory and adhesive changes inside the spinal canal were analyzed histopathologically in cats. To investigate the usefulness of a polyvinyl alcohol hydrogel sheet as an interposition over the dura to prevent inflammatory and adhesive reaction after laminectomy. A major concern after laminectomy is scar tissue formation that may result in extradural compression or make subsequent surgery to the same area difficult and hazardous. Wide laminectomy was performed at L5 in 30 adult cats. The dura was covered with a polyvinyl alcohol hydrogel sheet, free fat graft, or without interposition as a control. Animals were killed at 3 or 12 weeks. In the control group, adhesion of the exposed dura was apparent. Thick, fibrous connective tissue was observed between the dura and the paravertebral muscles. In the fat graft group, the dura was separated from the scar tissue by living grafted fat. However, the dura was adherent to the grafted fat and fibroblasts migrated into the interstitial space. In the polyvinyl alcohol hydrogel group, only a thin synovium-like layer was formed around the polyvinyl alcohol hydrogel sheet. Polyvinyl alcohol hydrogel is made of water and alcohol, and has been shown to be nontoxic to tissues. This is permeable to low molecular weight, but impermeable to large cells such as fibroblasts. Thus, the polyvinyl alcohol hydrogel sheet prevents migration of inflammatory cells and subsequently reduces intraspinal canal scar tissue formation and adhesive reaction. Other beneficial properties are extreme elasticity and low friction, which eliminate mechanical reaction to the spinal cord. The polyvinyl alcohol hydrogel sheet is believed to be useful in eliminating scar tissue formation and does not interfere with the dynamic gliding movement of the spinal cord and nerve roots.

  10. Microwave Measurements of Ferrite Polymer Composite Materials

    Directory of Open Access Journals (Sweden)

    Rastislav Dosoudil

    2004-01-01

    Full Text Available The article focuses on the microwave measurements performed on the nickel-zinc sintered ferrite with the chemical formula Ni0.3Zn0.7Fe2O4 produced by the ceramic technique and composite materials based on this ferrite and a non-magnetic polymer (polyvinyl chloride matrix. The prepared composite samples had the same particle size distribution 0-250um but different ferrite particle concentrations between 23 vol% and 80 vol%. The apparatus for measurement of the signal proportional to the absolute value of scattering parameter S11 (reflexion coefficient is described and the dependence of measured reflected signal on a bias magnetic field has been studied. By means of experiments, the resonances to be connected with the geometry of microwave experimental set-up were distinguished from ferromagnetic resonance arising in ferrite particles of composite structure. The role of local interaction fields of ferrite particles in composite material has been discussed.

  11. 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

  12. Investigation of the polyvinyl alcohol stabilization mechanism and adsorption properties on the surface of ternary mixed nanooxide AST 50 (Al2O3-SiO2-TiO2).

    Science.gov (United States)

    Wiśniewska, Małgorzata; Ostolska, Iwona; Szewczuk-Karpisz, Katarzyna; Chibowski, Stanisław; Terpiłowski, Konrad; Gun'ko, Vladimir Moiseevich; Zarko, Vladimir Iljich

    A new adsorbent consisting of fumed, mixed alumina, silica, and titania in various proportions (AST 50) was investigated. The studied material was prepared by chemical vapor deposition method. The diameter of AST 50 primary particles was equal to about 51 nm which denotes that it can be classified as a nanomaterial. In the presented paper, the adsorption properties of polyvinyl alcohol on the ternary oxide were investigated. The polymer macromolecules were characterized by two different molecular weights and degree of hydrolysis. The polymer adsorption reaches the maximum at pH 3 and decreases with the solution pH rise. The reduction of the adsorbed PVA macromolecules is related to the electrostatic repulsion forces occurring in the studied system. The AST 50 point of zero charge (pH pzc ) obtained from the potentiometric titration is equal to 4.7. Due to the nonionic character of the analyzed macromolecular compound, the polymer attendance has an insignificant effect on the AST 50 surface charge density. In the case of the adsorbent particles zeta potential, the obtained dependencies are different in the absence and presence of PVA. The shift of the slipping plane and displacement of the counter-ions from Stern layer by the adsorbed polymer chains have the greatest effect on the ζ potential value. The stability measurements indicate that the AST 50 suspensions in the presence of the background electrolyte at pH 3 and 6 are unstable. In turn, in an alkaline medium the mixed oxide suspensions exhibit the highest durability, which is a result of a large number of the negative charges on the AST 50 surface. The addition of PVA 100 significantly improves the suspension stability at pH 3 and 6; at higher pH value, the polymer presence does not influence the system durability. It is related to the steric and electrosteric stabilization of the colloidal particles by the adsorbed polyvinyl alcohol macromolecules.

  13. Investigation of the polyvinyl alcohol stabilization mechanism and adsorption properties on the surface of ternary mixed nanooxide AST 50 (Al{sub 2}O{sub 3}–SiO{sub 2}–TiO{sub 2})

    Energy Technology Data Exchange (ETDEWEB)

    Wiśniewska, Małgorzata; Ostolska, Iwona, E-mail: i-ostolska@wp.pl; Szewczuk-Karpisz, Katarzyna; Chibowski, Stanisław [Maria Curie-Sklodowska University, Department of Radiochemistry and Colloids Chemistry, Faculty of Chemistry (Poland); Terpiłowski, Konrad [Maria Curie-Sklodowska University, Department of Physical Chemistry – Interfacial Phenomena, Faculty of Chemistry (Poland); Gun’ko, Vladimir Moiseevich; Zarko, Vladimir Iljich [National Academy of Sciences in Ukraine, Institute of Surface Chemistry (Ukraine)

    2015-01-15

    A new adsorbent consisting of fumed, mixed alumina, silica, and titania in various proportions (AST 50) was investigated. The studied material was prepared by chemical vapor deposition method. The diameter of AST 50 primary particles was equal to about 51 nm which denotes that it can be classified as a nanomaterial. In the presented paper, the adsorption properties of polyvinyl alcohol on the ternary oxide were investigated. The polymer macromolecules were characterized by two different molecular weights and degree of hydrolysis. The polymer adsorption reaches the maximum at pH 3 and decreases with the solution pH rise. The reduction of the adsorbed PVA macromolecules is related to the electrostatic repulsion forces occurring in the studied system. The AST 50 point of zero charge (pH{sub pzc}) obtained from the potentiometric titration is equal to 4.7. Due to the nonionic character of the analyzed macromolecular compound, the polymer attendance has an insignificant effect on the AST 50 surface charge density. In the case of the adsorbent particles zeta potential, the obtained dependencies are different in the absence and presence of PVA. The shift of the slipping plane and displacement of the counter-ions from Stern layer by the adsorbed polymer chains have the greatest effect on the ζ potential value. The stability measurements indicate that the AST 50 suspensions in the presence of the background electrolyte at pH 3 and 6 are unstable. In turn, in an alkaline medium the mixed oxide suspensions exhibit the highest durability, which is a result of a large number of the negative charges on the AST 50 surface. The addition of PVA 100 significantly improves the suspension stability at pH 3 and 6; at higher pH value, the polymer presence does not influence the system durability. It is related to the steric and electrosteric stabilization of the colloidal particles by the adsorbed polyvinyl alcohol macromolecules.

  14. Gamma radiation grafted polymers for immobilization of Brucella antigen in diagnostic test studies

    Science.gov (United States)

    Docters, E. H.; Smolko, E. E.; Suarez, C. E.

    The radiation grafting process has a wide field of industrial applications, and in the recent years the immobilization of biocomponents in grafted polymeric materials obtained by means of ionizing radiations is a new and important contribution to biotechnology. In the present work, gamma preirradiation grafting method was employed to produce acrylics hydrogels onto polyethylene (PE), polyvinyl chloride (PVC) and polystyrene (PS). Two monomers were used to graft the previously mentioned polymers: methacrylic acid (MAAc) and acrylamide (AAm), and several working conditions were considered as influencing the degree of grafting. All this grafted polymers were used to study the possibility of a subsequent immobilization of Brucella antigen (BAg) in diagnostic test studies (ELISA).

  15. Thermal and IR studies on copper doped polyvinyl alcohol

    Indian Academy of Sciences (India)

    5 mol% PVA : mol% Cu2+ polymer films were prepared by casting process. Thermal transitions and thermal degradation of samples with respect to copper concentration were studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. Increase in glass transition temperature as ...

  16. Facile synthesis of thick films of poly(methyl methacrylate), poly(styrene), and poly(vinyl pyridine) from Au surfaces.

    Science.gov (United States)

    Saha, Sampa; Bruening, Merlin L; Baker, Gregory L

    2011-08-01

    Atom transfer radical polymerization (ATRP) is commonly used to grow polymer brushes from Au surfaces, but the resulting film thicknesses are usually significantly less than with ATRP from SiO(2) substrates. On Au, growth of poly(methyl methacrylate) (PMMA) blocks from poly(tert-butyl acrylate) brushes occurs more rapidly than growth of PMMA from initiator monolayers, suggesting that the disparity between growth rates from Au and SiO(2) stems from the Au surface. Radical quenching by electron transfer from Au is probably not the termination mechanism because polymerization from thin, cross-linked initiators gives film thicknesses that are essentially the same as the thicknesses of films grown from SiO(2) under the same polymerization conditions. However, this result is consistent with termination through desorption of thiols from noncross-linked films, and reaction of these thiols with growing polymer chains. The enhanced stability of cross-linked initiators allows ATRP at temperatures up to ∼100 °C and enables the growth of thick films of PMMA (350 nm), polystyrene (120 nm) and poly(vinyl pyridine) (200 nm) from Au surfaces in 1 h. At temperatures >100 °C, the polymer brush layers delaminate as large area films.

  17. Gamma radiation effect on molecular structure of poly(vinyl alcohol); Efeito da radiacao gama na estrutura molecular do poli (alcool vinilico)

    Energy Technology Data Exchange (ETDEWEB)

    Terence, Mauro Cesar [Universidade Presbiteriana Mackenzie, Sao Paulo, SP (Brazil). Dept. de Engenharia de Materiais]. E-mail: mterence@mackenzie.com.br; Guedes, Selma Matheus Loureiro [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil). Centro de Tecnologia das Radiacoes

    2005-07-01

    The poly(vinyl alcohol) (PVAL) is a polymer used as biomaterial. The PVAL was used as intra-ocular implant and can be used as a drug delivery system (DDS) for the pair PVAL/dihydroxy-propoximethyl guanine, where the last one is used for the treatment of people with retinite caused by cytomegalovirus. These implants are crosslinked systems. The crosslink was induced by gamma radiation applied in polymer. The samples of PVAL were irradiated with gamma rays with doses in the range from 0 up to 200 kGy. On irradiated PVAL samples was observed a light yellowness, attributed to the formation of polymeric radicals that are stable in the structure of polymer from radiolysis of PVAL. The tensile strength at break increase up to 200 kGy and the molecular weight increase up to 60 kGy, after that the PVAL is insoluble. The PVAL structural alteration was not observed up to 200 kGy, although crosslink occurred on PVAL. (author)

  18. Highly conductive quasi-coaxial electrospun quaternized polyvinyl alcohol nanofibers and composite as high-performance solid electrolytes

    Science.gov (United States)

    Liao, Guan-Ming; Li, Pin-Chieh; Lin, Jia-Shiun; Ma, Wei-Ting; Yu, Bor-Chern; Li, Hsieh-Yu; Liu, Ying-Ling; Yang, Chun-Chen; Shih, Chao-Ming; Lue, Shingjiang Jessie

    2016-02-01

    Electrospun quaternized polyvinyl alcohol (Q-PVA) nanofibers are prepared, and a potassium hydroxide (KOH)-doped nanofiber mat demonstrates enhanced ionic conductivity compared with a dense Q-PVA film with KOH doping. The Q-PVA composite containing 5.98% electrospun Q-PVA nanofibers exhibits suppressed methanol permeability. Both the high conductivity and suppressed methanol permeability are attributed to the quasi-coaxial structure of the electrospun nanofibers. The core of the fibers exhibits a more amorphous region that forms highly conductive paths, while the outer shell of the nanofibers contains more polymer crystals that serve as a hard sheath surrounding the soft core. This shell induces mass transfer resistance and creates a tortuous fuel pathway that suppresses methanol permeation. Such a Q-PVA composite is an effective solid electrolyte that makes the use of alkaline fuel cells viable. In a direct methanol alkaline fuel cell operated at 60 °C, a peak power density of 54 mW cm-2 is obtained using the electrospun Q-PVA composite, a 36.4% increase compared with a cell employing a pristine Q-PVA film. These results demonstrate that highly conductive coaxial electrospun nanofibers can be prepared through a single-opening spinneret and provide a possible approach for high-performance electrolyte fabrication.

  19. Enhanced performance of a direct methanol alkaline fuel cell (DMAFC) using a polyvinyl alcohol/fumed silica/KOH electrolyte

    Science.gov (United States)

    Lue, Shingjiang Jessie; Wang, Wei-Ting; Mahesh, K. P. O.; Yang, Chun-Chen

    A novel polymer-inorganic composite electrolyte for direct methanol alkaline fuel cells (DMAFCs) is prepared by physically blending fumed silica (FS) with polyvinyl alcohol (PVA) to suppress the methanol permeability of the resulting nano-composites. Methanol permeability is suppressed in the PVA/FS composite when comparing with the pristine PVA membrane. The PVA membrane and the PVA/FS composite are immersed in KOH solutions to prepare the hydroxide-conducting electrolytes. The ionic conductivity, cell voltage and power density are studied as a function of temperature, FS content, KOH concentration and methanol concentration. The PVA/FS/KOH electrolyte exhibits higher ionic conductivity and higher peak power density than the PVA/KOH electrolyte. In addition, the concentration of KOH in the PVA/FS/KOH electrolytes plays a major role in achieving higher ionic conductivity and improves fuel cell performance. An open-circuit voltage of 1.0 V and a maximum power density of 39 mW cm -2 are achieved using the PVA/(20%)FS/KOH electrolyte at 60 °C with 2 M methanol and 6 M KOH as the anode fuel feed and with humidified oxygen at the cathode. The resulting maximum power density is higher than the literature data reported for DMAFCs prepared with hydroxide-conducting electrolytes and anion-exchange membranes. The long-term cell performance is sustained during a 100-h continuous operation.

  20. Keratin/Polyvinyl Alcohol Blend Films Cross-Linked by Dialdehyde Starch and Their Potential Application for Drug Release

    Directory of Open Access Journals (Sweden)

    Yao Dou

    2015-03-01

    Full Text Available Feather keratin (FK extracted from feathers represents a valuable source of biodegradable and biocompatible polymer. The aim of this study was the development and characterization of blended films based on FK and polyvinyl alcohol (PVA cross-linked by dialdehyde starch (DAS for a potential drug release application. The compatibility of FK/PVA was improved when cross-linked by DAS: the relative crystallinity of the PVA/FK film slightly decreased, and the enthalpy value for the melting peak decreased by about 50% for the cross-linked films. The total soluble mass of all blend films in water was below 35% at 37 °C, indicating a good stability of the films in water. The results of the Rhodamine B dye (as a model drug release tests showed that the release rates decreased with increasing DAS content. DAS-induced cross-linking improves several important properties of the FK/PVA films, such as the compactness, the compatibility, and the stability in water. These improvements offer the potential to expand the application of FK films in the biomaterial field.

  1. Diffusion coefficient, porosity measurement, dynamic and equilibrium swelling studies of Acrylic acid/Polyvinyl alcohol (AA/PVA hydrogels

    Directory of Open Access Journals (Sweden)

    Nazar Mohammad Ranjha

    2015-06-01

    Full Text Available Objective of the present work was to synthesize hydrogels of acrylic acid/polyvinyl alcohol (AA/PVA by free radical polymerization by using glutaradehyde (GA as crosslinkers. The hydrogels were evaluated for swelling, diffusion coefficient and network parameters like the average molecular weight between crosslink’s, polymer volume fraction in swollen state, number of repeating units between crosslinks and crosslinking density by using Flory-Huggins theory. It was found that the degree of swelling of AA/PVA hydrogels increases greatly within the pH range 5-7. The gel fraction and porosity increased by increasing the concentration of AA or PVA. Increase in degree of crosslinking, decreased the porosity and inverse was observed in gel fraction. Selected samples were loaded with metoprolol tartrate. Drug release was studied in USP hydrochloric acid solution of pH 1.2 and phosphate buffer solutions of pH 5.5 and 7.5. Various kinetics models like zero order, first order, Higuchi and Peppas model were used for in vitro kinetic studies. The results showed that the drug release followed concentration dependent effect (First order kinetics with non-Fickian diffusion. FTIR and SEM used to study the structure, crystallinity, compatibility, thermal stability and morphology of prepared and drug loaded hydrogels respectively.

  2. Modification of structural and optical properties of polyvinyl alcohol/polyethylene glycol thin film by laser irradiation

    Science.gov (United States)

    Nouh, S. A.; Benthami, K.; Abutalib, M. M.

    2016-02-01

    The effect of infrared laser irradiation on the structural and the optical properties of polyvinyl alcohol/polyethylene glycol (PVA/PEG) co-polymer has been investigated. Thin films of PVA/PEG (nearly 50 µm thickness) were irradiated up to 15 J/cm2 of Ga-As laser pulses of 904 nm, 5 W power, and 200-ns pulse duration. The resultant effect of laser irradiation on the structural properties of PVA/PEG has been investigated using X-ray diffraction and Fourier transform infrared spectroscopy (FTIR). Further, the refractive index and the color difference between the exposed samples and the pristine have been studied. FTIR spectroscopy showed that the PVA/PEG samples exhibited degradation under the effect of laser irradiation up to 9 J/cm2, where crosslinking started and continued until 15 J/cm2. The refractive index had a minimum value of 1.5020 at 9 J/cm2, accompanied by a high degree of ordering and maximum value of 1.5640 at 15 J/cm2, with an increase in disordering character due to the degradation and crosslinking formation inside the sample, respectively. Moreover, the color intensity ΔE was greatly increased with increasing the laser fluence, accompanied by a significant increase in the yellow color component.

  3. Cold Spray Coating of Submicronic Ceramic Particles on Poly(vinyl alcohol) in Dry and Hydrogel States

    Science.gov (United States)

    Moreau, David; Borit, François; Corté, Laurent; Guipont, Vincent

    2017-06-01

    We report an approach using cold spray technology to coat poly(vinyl alcohol) (PVA) in polymer and hydrogel states with hydroxyapatite (HA). Using porous aggregated HA powder, we hypothesized that fragmentation of the powder upon cold spray could lead to formation of a ceramic coating on the surface of the PVA substrate. However, direct spraying of this powder led to complete destruction of the swollen PVA hydrogel substrate. As an alternative, HA coatings were successfully produced by spraying onto dry PVA substrates prior to swelling in water. Dense homogeneous HA coatings composed of submicron particles were obtained using rather low-energy spraying parameters (temperature 200-250 °C, pressure 1-3 MPa). Coated PVA substrates could swell in water without removal of the ceramic layer to form HA-coated hydrogels. Microscopic observations and in situ measurements were used to explain how local heating and impact of sprayed aggregates induced surface roughening and strong binding of HA particles to the molten PVA substrate. Such an approach could lead to design of ceramic coatings whose roughness and crystallinity can be finely adjusted to improve interfacing with biological tissues.

  4. Graphite oxide incorporated crosslinked polyvinyl alcohol and sulfonated styrene nanocomposite membrane as separating barrier in single chambered microbial fuel cell

    Science.gov (United States)

    Rudra, Ruchira; Kumar, Vikash; Pramanik, Nilkamal; Kundu, Patit Paban

    2017-02-01

    Different membranes with varied molar concentrations of graphite oxide (GO), 'in situ' polymerized sulfonated polystyrene (SS) and glutaraldehyde (GA) cross linked polyvinyl alcohol (PVA), have been analyzed as an effective and low cost nanocomposite barrier in single chambered microbial fuel cells (MFCs). The synthesized composite membranes, namely GO0.2, GO0.4 and GO0.6 exhibited comparatively better results with reduced water uptake (WU) and swelling ratios (SR) over the native PVA. The variation in properties is illustrated with membrane analyses, where GO0.4 showed an increased proton conductivity (PC) and ion exchange capacity (IEC) of 0.128 S cm-1 and 0.33 meq g-1 amongst all of the used membranes. In comparison, reduced oxygen diffusivity with lower water uptake showed a two-fold decrease in GO0.4 over pure PVA membrane (∼2.09 × 10-4 cm s-1). A maximum power density of 193.6 mW m-2 (773.33 mW m-3) with a current density of 803.33 mA m-2 were observed with GO0.4 fitted MFC, where ∼81.89% of chemical oxygen demand (COD) was removed using mixed firmicutes, as biocatalyst, in 25 days operation. In effect, the efficacy of GO incorporated crosslinked PVA and SS nanocomposite membrane has been evaluated as a polymer electrolyte membrane for harnessing bio-energy from single chambered MFCs.

  5. Reduction versus cross-linking: how to improve the tensile strength of graphene oxide/polyvinyl alcohol composite film

    Science.gov (United States)

    Tao, Cheng-an; Zhang, Hao; Huang, Jian; Zou, Xiaorong; Zhu, Hui; Wang, Jianfang

    2017-08-01

    Both reduction and cross-linking can improve the mechanical performance of graphene/polymer composites. However, few reports exist on the comparison and combination of both methods. Taking graphene oxide/polyvinyl alcohol composite film as its model, this study focuses on the effect of reduction and cross-linking (as well as their order) on the composite film’s tensile strength. GO/PVA composite films were prepared by a simple solution mixing method, then reduced with hydroiodic acid and cross-linked with glutaraldehyde. Both reduction and cross-linking can improve the tensile strength, but the effect of cross-linking is superior. The improvement of tensile strength is cumulative when reduction and cross-linking are used simultaneously or even successively. Moreover, the order in which these two methods are applied also plays a role; reduction first with cross-linking second shows superior results than the reverse. The tensile strength of the obtained composite film peaked at 112.8 MPa, which is over 7 times that of neat PVA.

  6. Dual-crosslinked poly(vinyl alcohol)/sodium alginate/silver nanocomposite beads - A promising antimicrobial material.

    Science.gov (United States)

    Narayanan, Kannan Badri; Han, Sung Soo

    2017-11-01

    In this paper, we report the immobilization of borate-stabilized silver nanoparticles (AgNPs) as nanofillers in dual-crosslinked polymers comprised of poly(vinyl alcohol) (PVA) and sodium alginate (SA) at different ratios. Ionic-crosslinking using Ca(2+) ions and physical-crosslinking by freeze-thawing were used to entrap silver nanoparticles in the prepared PVA/SA/AgNPs nanocomposite beads. These polymeric nanocomposites were characterized by UV-Vis, XRD, FE-SEM, FT-IR, TGA, and using rheological and swelling properties. The antibacterial activities of these PVA/SA/AgNPs nanocomposites were evaluated against Escherichia coli O157: H7, which causes escherichiosis through contaminated food and water. The results obtained indicated that PVA/SA/AgNPs nanocomposite formed with a ratio 10/90 of PVA to SA (formulation F5) exhibited high bactericidal activity, with entrapment of AgNPs and had excellent rheological and thermal stabilities. Due to the low cost and effectiveness of these antimicrobial nanocomposites, they have potential as an active food-packaging material for food safety and to extend shelf-life of packaged foods. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Enhanced mechanical, thermal and antimicrobial properties of poly(vinyl alcohol)/graphene oxide/starch/silver nanocomposites films.

    Science.gov (United States)

    Usman, Adil; Hussain, Zakir; Riaz, Asim; Khan, Ahmad Nawaz

    2016-11-20

    In the present work, synthesis of poly(vinyl alcohol)/graphene oxide/starch/silver (PVA/GO/Starch/Ag) nanocomposites films is reported. Such films have been characterized and investigated for their mechanical, thermal and antimicrobial properties. The exfoliation of GO in the PVA matrix occurs owing to the non-covalent interactions of the polymer chains of PVA and hydrophilic surface of the GO layers. Presence of GO in PVA and PVA/starch blends were found to enhance the tensile strength of the nanocomposites system. It was found that the thermal stability of PVA as well as PVA/starch blend systems increased by the incorporation of GO where strong physical bonding between GO layers and PVA/starch blends is assumed to cause thermal barrier effects. Antimicrobial properties of the prepared films were investigated against Escherichia coli and Staphylococcus aureus. Our results show enhanced antimicrobial properties of the prepared films where PVA-GO, PVA-Ag, PVA-GO-Ag and PVA-GO-Ag-Starch showed antimicrobial activity in ascending order. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Programmable Shape Recovery Process of Water-Responsive Shape-Memory Poly(vinyl alcohol) by Wettability Contrast Strategy.

    Science.gov (United States)

    Fang, Zhiqiang; Kuang, Yudi; Zhou, Panpan; Ming, Siyi; Zhu, Penghui; Liu, Yu; Ning, Honglong; Chen, Gang

    2017-02-15

    Water-responsive shape-memory polymers (SMPs) are desirable for biomedical applications, but their limited shape recovery process is problematic. Herein, we demonstrate a shape-memory poly(vinyl alcohol) (SM-PVA) with programmable multistep shape recovery processes in water via a wettability contrast strategy. A hexamethyldisilazane (HMDS)-treated SiO2 nanoparticle layer with varying loading weights was rationally deposited onto the surface of SM-PVA, aiming to create surface-wettability contrast. The varying wettability led to different water adsorption behaviors of SM-PVA that could be well-described by the pseudo-first-order kinetic model. The results calculated from the kinetic model showed that both the pseudo-first order-adsorption rate constant and the saturated water absorption of SM-PVA demonstrated a declining trend as the loading weight of SiO2 increased, which laid the foundation for the local regulation of the water-responsive rate of SM-PVA. Finally, two proof-of-concept drug-delivery devices with diverse three-dimensional structures and actuations are presented based on the water-responsive SM-PVA with preprogrammed multistep shape recovery processes. We believe the programmable shape-memory behavior of water-responsive SM-PVA could highly extend its use in drug delivery, tissue engineering scaffolds, and smart implantable devices, etc.

  9. Immobilization of phospholipase a1 using a polyvinyl alcohol-alginate matrix and evaluation of the effects of immobilization

    Directory of Open Access Journals (Sweden)

    J. F. Zhan

    2013-12-01

    Full Text Available The paper presents the synthesis and performance of an immobilized phospholipase A1 with practical application for oil degumming. The polyvinyl alcohol (PVA had a number of properties indicating this polymer as a good enzyme carrier. The combination with alginate made a macro-porous structure, evidenced by SEM analyses. When the process time in boric acid solution was 30 minutes, the results revealed that beads prepared with 10% (w/v PVA and 2% (w/v sodium alginate in 4% (w/v boric acid and 2% (w/v calcium chloride solution exhibited high immobilized enzyme activity, immobilization yield and stability. The pH and temperature optimum for the PVA-alginate immobilized phospholipase A1were 5.6 and 58 °C, respectively. The enzyme immobilized in the beads retained 50.37% of the initial activity in the eighth cycle. The enzyme biocatalyst immobilized in the beads retained 78.58% of the initial activity after storing 6 weeks at 4 °C.

  10. Physically crosslinked poly(vinyl alcohol-hydroxyethyl starch blend hydrogel membranes: Synthesis and characterization for biomedical applications

    Directory of Open Access Journals (Sweden)

    El-Refaie Kenawy

    2014-07-01

    Full Text Available Poly(vinyl alcohol, PVA is a polymer of great importance because of its many appealing characteristics specifically for various pharmaceutical and biomedical applications. Physically crosslinked hydrogel membranes composed of different amounts of hydroxyethyl starch (HES in (PVA and ampicillin were prepared by applying freeze–thawing method. This freezing–thawing cycle was repeated for three consecutive cycles. Physicochemical properties of PVA–HES membrane gel such as gel fraction, swelling, morphology, elongation, tensile strength, and protein adsorption were investigated. Introducing HES into freeze–thawed PVA structure affected crystal size distribution of PVA; and hence physicochemical properties and morphological structure have been affected. Increased HES concentration decreased the gel fraction %, maximum strength and break elongation. Indeed it resulted into a significant incrementing of the swelling ability, amount of protein adsorption, broader pore size, and pore distribution of membrane morphological structure. Furthermore, an increase in HES concentration resulted in better and still lower thermal stability compared to virgin PVA and freeze–thawed PVA. The maximum weight loss of PVA–HES hydrogel membranes ranged between 18% and 60% according to HES content, after two days of degradation in phosphate buffer saline (PBS, which indicates they are biodegradable. Thus, PVA–HES hydrogel membranes containing ampicillin could be a novel approach for biomedical application e.g. wound dressing purposes.

  11. Studies on soy protein isolate/polyvinyl alcohol hybrid nanofiber membranes as multi-functional eco-friendly filtration materials

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Qun; Zhu, Ming; Yu, Siruo; Sui, Gang, E-mail: suigang@mail.buct.edu.cn; Yang, Xiaoping

    2016-12-15

    Highlights: • Biodegradable filtration membranes were prepared. • Polar groups in the membrane surface helped capture fine particles. • Loading filtration efficiency can reach 99.99% in the case of small pressure drop. • Filtration membrane showed antimicrobial activity to Escherichia coli. - Abstract: A biodegradable and multifunctional air filtration membrane was prepared by electrospinning of soy protein isolate (SPI)/polyvinyl alcohol (PVA) system in this paper. The optimized SPI/PVA proportion in the spinning solution was determined according to the analyses of microstructure, surface chemical characteristic and mechanical property of the hybrid nanofiber membranes. Under the preferred preparation condition, two kinds of polymer materials displayed a good compatibility in the hybrid nanofibers, and a large number of polar groups existed in the membrane surface. The loading filtration efficiency of the nanofiber membrane with optimal material ratio and areal density can reach 99.99% after test of 30 min for fine particles smaller than 2.5 μm in the case of small pressure drop. Besides, this kind of filtration membrane showed an antimicrobial activity to Escherichia coli in the study. The SPI/PVA hybrid nanofiber membrane with proper material composition and microstructure can be used as a new type of high performance eco-friendly filtration materials.

  12. Fabrication, Characterization, and Antibacterial Properties of Electrospun Membrane Composed of Gum Karaya, Polyvinyl Alcohol, and Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Vinod Vellora Thekkae Padil

    2015-01-01

    Full Text Available Gum karaya (GK, a natural hydrocolloid, was mixed with polyvinyl alcohol (PVA at different weight ratios and electrospun to produce PVA/GK nanofibers. An 80 : 20 PVA/GK ratio produced the most suitable nanofiber for further testing. Silver nanoparticles (Ag-NPs were synthesised through chemical reduction of AgNO3 (at different concentrations in the PVA/GK solution, the GK hydroxyl groups being oxidised to carbonyl groups, and Ag+ cations reduced to metallic Ag-NPs. These PVA/GK/Ag solutions were then electrospun to produce nanofiber membranes containing Ag-NPs (Ag-MEMs. Membrane morphology and other characteristics were analysed using scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy, and UV-Vis and ATR-FTIR spectroscopy. The antibacterial activity of the Ag-NP solution and Ag-MEM was then investigated against Gram-negative Escherichia coli and Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus. Our results show that electrospun nanofiber membranes based on natural hydrocolloid, synthetic polymer, and Ag-NPs have many potential uses in medical applications, food packaging, and water treatment.

  13. 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...

  14. Conducting Polymers

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 12. Conducting Polymers - From a Laboratory Curiosity to the Market Place. S Ramakrishnan. Volume 16 Issue 12 December 2011 pp 1254-1265. Fulltext. Click here to view fulltext PDF. Permanent link:

  15. Polymer Microneedles

    NARCIS (Netherlands)

    Yeshurun, Yehoshua; Hefetz, Meir; Berenschot, Johan W.; de Boer, Meint J.; Altpeter, Dominique; Boom, Garrit; Boom, G.

    2003-01-01

    A method for producing microneedles. The method including disposing a first layer of a radiation sensitive polymer on to a working surface and selectively irradiating the first layer such that the first layer has at least one irradiated region and at least one non-irradiated region. The method also

  16. Exotic nuclear excitations

    CERN Document Server

    Pancholi, S C

    2011-01-01

    By providing the reader with a foundational background in high spin nuclear structure physics and exploring exciting current discoveries in the field, this book presents new phenomena in a clear and compelling way. The quest for achieving the highest spin states has resulted in some remarkable successes which this monograph will address in comprehensive detail. The text covers an array of pertinent subject matter, including the rotational alignment and bandcrossings, magnetic rotation, triaxial strong deformation and wobbling motion and chirality in nuclei. Dr. Pancholi offers his readers a clearly-written and up-to-date treatment of the topics covered. The prerequisites for a proper appreciation are courses in nuclear physics and nuclear models and measurement techniques of observables like gamma-ray energies, intensities, multi-fold coincidences, angular correlations or distributions, linear polarization, internal conversion coefficients, short lifetime (pico-second range) of excited states etc. and instrum...

  17. Hydrogels based on interpenetrating network of chitosan and polyvinyl pyrrolidone for pH-sensitive delivery of repaglinide.

    Science.gov (United States)

    Vaghani, Subhash S; Patel, Madhabhai M

    2011-06-01

    The aim of this study was to develop a pH-sensitive chitosan/polyvinyl pyrrolidone (PVP) based controlled drug release system for repaglinide. The hydrogels were synthesised by crosslinking chitosan and PVP blend with glutaraldehyde to form a semi-interpenetrating polymer network (semi-IPN). These semi-IPNs were studied for their content uniformity, swelling index (SI), mucoadhesion, wettability, in vitro release and their release kinetics. The hydrogels showed more than 95% loading of repaglinide. These hydrogels showed high swelling and mucoadhesion under acidic conditions. The swelling was found due to the protonation of a primary amino group on chitosan. In acidic condition chitosan was ionized, and adhesion occurred between the positively charged chitosan and the negatively charged mucus. In the physiological condition less swelling was noticed. In vitro release study revealed that formulation containing chitosan (2% w/v) and PVP (4% w/v) in the ratio of 14:6 w/w showed complete drug release after 12h. Release profile showed that all the formulations followed non-fickian diffusion mechanism (diffusion coupled with swelling). Fourier transform infrared (FTIR) spectroscopic analysis revealed proper crosslinking of polymer and formation of semi-IPN as well as presence of drug in the formulation. Differential scanning calorimetry (DSC) and powder x-ray diffraction (p-XRD) study revealed the presence of repaglinide in crystalline form in the formulations. The surface morphology of semi-IPN was studied before and after dissolution in simulated gastric fluid (SGF, pH 1.2) which indicated generation of open channel-like structure in hydrogel after dissolution. The results of study suggest that semi-IPNs of chitosan/PVP are potent candidates for delivery of repaglinide in acidic environment.

  18. Changes induced by UV radiation in the presence of sodium benzoate in films formulated with polyvinyl alcohol and carboxymethyl cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Villarruel, S. [Faculty of Exact Sciences, UNLP (Argentina); Giannuzzi, L.; Rivero, S. [Center for Research and Development in Food Cryotechnology (CCT-CONICET La Plata), 47 and 116 (Argentina); Pinotti, A., E-mail: acaimpronta@hotmail.com [Center for Research and Development in Food Cryotechnology (CCT-CONICET La Plata), 47 and 116 (Argentina); Faculty of Engineering, UNLP, La Plata 1900 (Argentina)

    2015-11-01

    This work was focused on: i) developing single and blend films based on carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVOH) studying their properties, ii) analyzing the interactions between CMC and PVOH and their modifications UV-induced in the presence of sodium benzoate (SB), and iii) evaluating the antimicrobial capacity of blend films containing SB with and without UV treatment. Once the blend films with SB were exposed to UV radiation, they exhibited lower moisture content as well as a greater elongation at break and rougher surfaces compared to those without treatment. Considering oxygen barrier properties, the low values obtained would allow their application as packaging with selective oxygen permeability. Moreover, the characteristics of the amorphous phase of the matrix prevailed with a rearrangement of the structure of the polymer chain, causing a decrease of the crystallinity degree. These results were supported by X-rays and DSC analysis. FT-IR spectra reflected some degree of polymer–polymer interaction at a molecular level in the amorphous regions. The incorporation of sodium benzoate combined with UV treatment in blend films was positive from the microbial point of view because of the growth inhibition of a wide spectrum of microorganisms. From a physicochemical perspective, the UV treatment of films also changed their morphology rendering them more insoluble in water, turning the functionalized blend films into a potential material to be applied as food packaging. - Highlights: • CMC:PVOH blend films were developed with the addition of sodium benzoate (SB). • Exposition to UV radiation was carried out with sodium benzoate as photoinitiator. • Blend films were exposed to UV radiation to modify their surface morphology. • Low O{sub 2} permeability of UV treated blends allow them to be used as selective packaging. • Efficacy of SB as an antimicrobial agent was examined with and without UV radiation.

  19. Excitable scale free networks

    Science.gov (United States)

    Copelli, M.; Campos, P. R. A.

    2007-04-01

    When a simple excitable system is continuously stimulated by a Poissonian external source, the response function (mean activity versus stimulus rate) generally shows a linear saturating shape. This is experimentally verified in some classes of sensory neurons, which accordingly present a small dynamic range (defined as the interval of stimulus intensity which can be appropriately coded by the mean activity of the excitable element), usually about one or two decades only. The brain, on the other hand, can handle a significantly broader range of stimulus intensity, and a collective phenomenon involving the interaction among excitable neurons has been suggested to account for the enhancement of the dynamic range. Since the role of the pattern of such interactions is still unclear, here we investigate the performance of a scale-free (SF) network topology in this dynamic range problem. Specifically, we study the transfer function of disordered SF networks of excitable Greenberg-Hastings cellular automata. We observe that the dynamic range is maximum when the coupling among the elements is critical, corroborating a general reasoning recently proposed. Although the maximum dynamic range yielded by general SF networks is slightly worse than that of random networks, for special SF networks which lack loops the enhancement of the dynamic range can be dramatic, reaching nearly five decades. In order to understand the role of loops on the transfer function we propose a simple model in which the density of loops in the network can be gradually increased, and show that this is accompanied by a gradual decrease of dynamic range.

  20. Polyvinyl chloride plastisol breast phantoms for ultrasound imaging.

    Science.gov (United States)

    de Carvalho, Isabela Miller; De Matheo, Lucas Lobianco; Costa Júnior, José Francisco Silva; Borba, Cecília de Melo; von Krüger, Marco Antonio; Infantosi, Antonio Fernando Catelli; Pereira, Wagner Coelho de Albuquerque

    2016-08-01

    Ultrasonic phantoms are objects that mimic some features of biological tissues, allowing the study of their interactions with ultrasound (US). In the diagnostic-imaging field, breast phantoms are an important tool for testing performance and optimizing US systems, as well as for training medical professionals. This paper describes the design and manufacture of breast lesions by using polyvinyl chloride plastisol (PVCP) as the base material. Among the materials available for this study, PVCP was shown to be stable, durable, and easy to handle. Furthermore, it is a nontoxic, nonpolluting, and low-cost material. The breast's glandular tissue (image background) was simulated by adding graphite powder with a concentration of 1% to the base material. Mixing PVCP and graphite powder in differing concentrations allows one to simulate lesions with different echogenicity patterns (anechoic, hypoechoic, and hyperechoic). From this mixture, phantom materials were obtained with speed of sound varying from 1379.3 to 1397.9ms(-1) and an attenuation coefficient having values between 0.29 and 0.94dBcm(-1) for a frequency of 1MHz at 24°C. A single layer of carnauba wax was added to the lesion surface in order to evaluate its applicability for imaging. The images of the phantoms were acquired using commercial ultrasound equipment; a specialist rated the images, elaborating diagnoses representative of both benign and malignant lesions. The results indicated that it was possible to easily create a phantom by using low-cost materials, readily available in the market and stable at room temperature, as the basis of ultrasonic phantoms that reproduce the image characteristics of fatty breast tissue and typical lesions of the breast. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. STABILITY AND CHARACTERIZATION OF CNT NANOFLUIDS USING POLYVINYL ALCOHOL DISPERSANT

    Directory of Open Access Journals (Sweden)

    S. W. TAM

    2016-02-01

    Full Text Available In this research, CNT-water nanofluids are synthesized using polyvinyl alcohol (PVA dispersant where each of the CNT concentration ranging from 0.01 to 0.1 wt% is tested with 0.25 to 3.00 wt% of PVA to optimize the dispersion and stability of nanofluids. The nanofluids are sonicated for 4 hours using ultrasonic water bath and the stability is analyzed using UV-Vis spectrophotometer. The dispersion state of the CNT-water nanofluid is further examined using optical microscope. The stable nanofluids of each CNT concentration identified were then tested for their thermo-physical properties such as thermal conductivity and viscosity with respect to temperature ranging from 25 to 70 °C. The results revealed that 0.5 to 1.5 wt% of PVA dispersant give the optimum stability to the entire range of CNT concentration studied. It was found that the thermal conductivity enhancement of CNT-water nanofluid stabilized by PVA increased non-linearly with temperature. Although PVA suppressed the thermal conductivity of water, the addition of CNT is able to surpass its effect and the results showed that there is approximately 1 to 44 % enhancement for the range of CNT concentration and temperature studied. It was also observed that the viscosity for 1.5 wt% of PVA aqueous solution at 25 °C is approximately 7.5 mPa.s, which is significantly greater than water. However, the presence of CNT nanoparticles is able to reduce the viscosity of its respective optimum PVA solution by 2 to 6% for the entire range of CNT concentrations investigated, showcasing self-lubrication effect of CNT. Moreover, the viscosity of the nanofluids decreases significantly with increasing temperature.

  2. A (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer)-dispersed sustained-release tablet for imperialine to simultaneously prolong the drug release and improve the oral bioavailability.

    Science.gov (United States)

    Lin, Qing; Fu, Yu; Li, Jia; Qu, Mengke; Deng, Li; Gong, Tao; Zhang, Zhirong

    2015-11-15

    Imperialine, extracted from Bulbus Fritillariae Cirrhosae, is an efficient antitussive and expectorant medicine. However, its short half-life and stomach degradation limited imperialine from further clinical use. The current study was conducted to develop a sustained-release tablet for imperialine both to prolong absorption time and to improve the oral bioavailability of the drug. The tablets were prepared by a direct compression method formulated on optimized solid dispersion (SD) for imperialine based on polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus(®)) with imperialine/Soluplus(®) ratio of 1:8 (w/w). In order to obtain the optimized formulation, factors that affected the drug release were investigated by in vitro dissolution studies in the media of pH1.2, 5.8, 7.0 and 7.4. Powder X-ray diffraction and scanning electron microscope confirmed that the imperialine in SD was amorphous instead of crystalline, and still stayed amorphous even after the direct compression. And besides, pharmacokinetic study in Beagle dogs was performed to inspect the in vivo sustained release. Plasma concentration-time curves and pharmacokinetic parameters were gained. As a result, the Cmax of imperialine was one-fold reduced and Tmax was two-fold prolonged, and the mean AUC0-24 was expressed as 89.581±21.243μgh/L, which showed that the oral bioavailability of imperialine was 2.46-fold improved. Moreover, the in vitro-in vivo correlation was recommended to carry out, demonstrating the percentages of drug release in vitro were well-correlated with the absorptive fraction in vivo with the correlation coefficients above 0.9900. By mathematically modeling and moment imaging of the drug release, Peppas equation was selected as the most fitted model for the sustained-release tablets with the diffusional coefficient in the range of 0.59-0.62, indicating the release of imperialine from the sustained-release tablets was an anomalous process involving

  3. Applications of polymers in intraocular drug delivery systems

    Directory of Open Access Journals (Sweden)

    Ali Mohammed Alhalafi

    2017-01-01

    Full Text Available We are entering a new era of ophthalmic pharmacology where new drugs are rapidly being developed for the treatment of anterior and posterior segment of the eye disease. The pharmacokinetics of drug delivery to the eye remains a very active area of ophthalmic research. Intraocular drug delivery systems allow the release of the drug, bypassing the blood–ocular barrier. The main advantage of these preparations is that they can release the drug over a long time with one single administration. These pharmaceutical systems are of great important in the treatment of the posterior segment diseases, and they can be prepared from biodegradable or nonbiodegradable polymers. Biodegradable polymers have the advantage of disappearing from the site of action after releasing the drug. The majority of intraocular devices are prepared from nonbiodegradable polymers, and they can release controlled amounts of drugs for months. Nonbiodegradable polymers include silicone, polyvinyl alcohol, and ethylene-vinyl acetate. The polymers usually employed to prepare nanoparticles for the topical ophthalmic route are poly (acrylic acid derivatives (polyalquilcyanocrylates, albumin, poly-μ-caprolactone, and chitosan. Dendrimers are a recent class of polymeric materials with unique nanostructure which has been studied to discover their role in the delivery of therapeutics and imaging agents. Hydrogels are polymers that can swell in aqueous solvent system, and they hold the solvents in a swollen cross-linked gel for delivery. This review exhibits the current literature regarding applications of polymers in ophthalmic drug delivery systems including pharmacokinetics, advantages, disadvantages, and indications aimed to obtain successful eye therapy. Method of Literature Search: A systematic literature review was performed using PubMed databases into two steps. The first step was oriented to classification of intraocular polymers implants focusing on their advantages and

  4. [Medical prophylaxis of occupational intoxication in polyvinyl chloride industry].

    Science.gov (United States)

    Maniashin, Iu A; Potrokhov, O I; Belik, G A; Bol'shedvorskiĭ, V V; Lokhov, M G

    1995-01-01

    The study covered clinical and laboratory findings, immunity parameters in 103 workers of polymer compounds production. The individuals exposed to chlorine organic chemicals: mercuric vapors, gaseous chlorine demonstrate specific changes of metabolic parameters. The data on protein synthesis, monooxygenases activity, lipid metabolism, state of membranes (lipoprotein complex, peroxidases, ALa-AT, Asp-AT), immune activity enabled to design prophylactic measures. To accomplish the therapeutic measures, the department for prevention of occupational intoxication is organized in local industrial medical center.

  5. High-flow priapism treated with superselective transcatheter embolization using polyvinyl alcohol particles

    Directory of Open Access Journals (Sweden)

    Sebastián Sánchez-López

    2017-02-01

    Full Text Available Objectives: Priapism is a persistent erection of the penis not associated with sexual stimulation. High-flow priapism is caused by unregulated arterial inflow, usually preceded by perineal or penile blunt trauma and formation of an arterial-lacunar fistula. We present a case of high-flow priapism in a 13-year-old patient managed with polyvinyl alcohol particles. Methods: After obtaining informed consent of the parents of the minor, diagnosis was made with penile Color Doppler Ultrasound and confirmed with flush angiography. Selective arterial embolization was performed with the use of polyvinyl alcohol particles. Results: Complete detumescence was achieved without compromising the patient’s erectile function. Conclusions: The use of permanent occlusive agents like polyvinyl alcohol particles for embolization shows good occlusion rates compared to temporary agents. More studies are needed to find the safer and better agent for the treatment of high flow priapism without compromising erectile function.

  6. Preparation and characterization of polyvinyl alcohol—chitosan biocompatible magnetic microparticles

    Science.gov (United States)

    Elena Udrea, Laura; Hritcu, Doina; Popa, Marcel Ionel; Rotariu, Ovidiu

    2011-01-01

    This work addresses the obtaining of biocompatible magnetic polyvinyl alcohol—chitosan microspheres, specifically tailored/functionalised to bind directly blood toxins using an emulsion crosslinking preparation method. The following synthesis parameters were studied: water to oil phase ratio, polyvinyl alcohol molecular weight, chitosan to polyvinyl alcohol weight ratio, surfactant composition and concentration of the crosslinking agent. These parameters were optimized for producing a high yield of colloidally stable and uniformly sized particles with significant magnetization of saturation, bearing surface amino groups that can be further used to bind blood toxins directly. The particles were characterized regarding their size distribution and surface charge (laser diffraction analysis), morphology (transmission electron microscopy), magnetic properties, chemical composition (Fourier transform infrared spectroscopy) and concentration of the surface amino groups (conductometric titration).

  7. Radiation processing of indigenous natural polymers. Properties of radiation modified blends from sago-starch for biodegradable composite

    Energy Technology Data Exchange (ETDEWEB)

    Ghazali, Z.; Dahlan, K.Z. [Malaysian Institute for Nuclear and Technology Research (MINT), Bangi, Kajang (Malaysia); Wongsuban, B.; Idris, S.; Muhammad, K. [Universiti Putra Malaysia, Faculty of Food Science and Biotechnology, Department of Food Science, Serdang (Malaysia)

    2001-03-01

    Research and development on biodegradable polymer blends and composites have gained wider interest to offer alternative eco-friendly products. Natural polysaccharide such as sago-starch offers the most promising raw material for the production of biodegradable composites. The potential of sago, which is so abundant in Malaysia, to produce blends for subsequent applications in composite material, was evaluated and explored. Blends with various formulations of sago starch and polyvinyl alcohol (PVA), and polyvinyl pyrrolidone (PVP) polymers were prepared and subjected to radiation modification using electron beam irradiation. The effect of irradiation on the sago and its blends was evaluated and their properties were characterized. The potential of producing composite from sago blends was explored. Foams from these blends were produced using microwave oven while films were produced through casting method. The properties such as mechanical, water absorption, expansion ratio, and biodegradability were characterized and reported in this paper. (author)

  8. Effect of Polymers (PEG and PVP on Sol-Gel Synthesis of Microsized Zinc Oxide

    Directory of Open Access Journals (Sweden)

    Thilagavathi Thirugnanam

    2013-01-01

    Full Text Available Fibers irregular and seed-like microcrystalline ZnO were synthesized by using a cost-effective and low temperature aqueous sol-gel method. Various polymers, namely, polyethylene glycol 6000 (PEG 6000 and polyvinyl pyrrolidone (PVP, were used as structure directing agents. The samples were characterized by X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR, and scanning electron microscopy (SEM. The X-ray diffraction pattern revealed the formation of phase-pure ZnO micropowders. It is observed that the polymers play an important role in modifying the surface morphology and the size of the crystallites. A compact granular morphology is observed for the ZnO samples without polymer. The samples exhibit microparticles of size 100 nm for PVP and for PEG-mediated growth, whereas microporous corrugated morphology is observed for added PEG-mediated micropowder. FTIR study is used to confirm the structural modifications occurring in the polymers.

  9. Structural and Thermal Studies of ZnS and CdS Nanoparticles in Polymer Matrices

    Directory of Open Access Journals (Sweden)

    Jejenija Osuntokun

    2016-01-01

    Full Text Available We report the synthesis and structural studies of ZnS and CdS nanoparticles in polyvinylpyrrolidone (PVP, poly(vinyl alcohol (PVA, and poly(methyl methacrylate (PMMA matrices. The metal sulfides/polymer nanocomposites were characterized by X-ray diffraction (XRD, Fourier transform infrared spectroscopy, electronic spectroscopy (UV-Vis, transmission electron microscopy (TEM, and thermogravimetric analysis (TGA. The particle sizes as calculated from the absorption spectra were in agreement with the results obtained from TEM and XRD data. They showed metal sulfides nanoparticles in the polymers matrices with average crystallite sizes of 1.5–6.9 nm. The TGA results indicate that incorporation of the nanoparticles significantly altered the thermal properties of the respective polymers with ZnS/PVA and CdS/PVA nanocomposites displaying higher thermal stability than the other polymer nanocomposites.

  10. Low-Ceiling-Temperature Polymer Microcapsules with Hydrophobic Payloads via Rapid Emulsion-Solvent Evaporation.

    Science.gov (United States)

    Tang, Shijia; Yourdkhani, Mostafa; Possanza Casey, Catherine M; Sottos, Nancy R; White, Scott R; Moore, Jeffrey S

    2017-06-14

    We report a microencapsulation procedure based on rapid solvent evaporation to prepare microcapsules with hydrophobic core materials and low-ceiling-temperature polymer shell wall of cyclic poly(phthalaldehyde) (cPPA). We use and compare microfluidic and bulk emulsions. In both methods, rapid solvent evaporation following emulsification resulted in kinetically trapped core-shell microcapsules, whereas slow evaporation resulted in acorn morphology. Through the systematic variation of encapsulation parameters, we found that polymer-to-core weight ratios higher than 1 and polymer concentrations higher than 4.5 wt % in the oil phase were required to obtain a core-shell structure. This microencapsulation procedure enabled the fabrication of microcapsules with high core loading, controlled size, morphology, and stability. This procedure is versatile, allowing for the encapsulation of other hydrophobic core materials, i.e., mineral oil and organotin catalyst, or using an alternative low-ceiling-temperature polymer shell wall, poly(vinyl tert-butyl carbonate sulfone).

  11. Impedance studies of a green blend polymer electrolyte based on PVA and Aloe-vera

    Science.gov (United States)

    Selvalakshmi, S.; Mathavan, T.; Vijaya, N.; Selvasekarapandian, Premalatha, M.; Monisha, S.

    2016-05-01

    The development of polymer electrolyte materials for energy generating and energy storage devices is a challenge today. A new type of blended green electrolyte based on Poly-vinyl alcohol (PVA) and Aloe-vera has been prepared by solution casting technique. The blending of polymers may lead to the increase in stability due to one polymer portraying itself as a mechanical stiffener and the other as a gelled matrix supported by the other. The prepared blend electrolytes were subjected to Ac impedance studies. It has been found out that the polymer film in which 1 gm of PVA was dissolved in 40 ml of Aloe-vera extract exhibits highest conductivity and its value is 3.08 × 10-4 S cm-1.

  12. The glass transition and interfacial dynamics of single strand fibers of polymers.

    Science.gov (United States)

    Cho, Hyun Woo; Sung, Bong June

    2017-02-08

    We investigate the glass transition and interfacial dynamics of single strand fibers of flexible polymers by employing molecular dynamics (MD) simulations along with a coarse grained model. While the polymer fiber has drawn significant attention due to its applicability in tissue engineering and stretchable electronics, its dynamic properties, especially the glass transition temperature (Tg), are yet to be understood at the molecular level. For example, there has been a controversy on the effect of the polymer fiber radius (R) on Tg: Tg decreased with a decrease in R for some polymer fibers, whereas Tg of other polymer fibers was not sensitive to R. In this article, we estimate the bond relaxation time of polymers and evaluate both Tg and fragility (m) as a function of R. We illustrate that Tg of the polymer fiber decreased with a decrease in R monotonically and also that the values of Tg follow faithfully the empirical equation proposed by Keddie et al. as a function of R, which was successfully employed to fit the values of Tg of both polyvinyl alcohol (PVA) fibers and polyethylene (PE) fibers. We also find that the dynamics of polymers at the interface between a polymer fiber and air is faster than that of polymers at the center. By employing Adam-Gibbs theory, we show that the fast interface dynamics of polymer fibers should influence the cooperative motion of monomers, which should be responsible for the decrease in Tg for smaller values of R. Near the interface there are more mobile monomers that participate in the cooperative motions of polymers. Interesting is that due to the curved surface (unlike flat polymer films) the cooperative motion of monomers is anisotropic in polymer fibers.

  13. Polymer fiber waveguides for terahertz radiation

    DEFF Research Database (Denmark)

    Nielsen, Kristian

    is taken from microstructured polymer optical fibers (mPOFs) used at optical wavelengths for sensing and communication. The fibers investigated can be divided into two groups, the solid core fibers and the hollow core fibers. The solid core fibers offer the broadest bandwidth with the best dispersion....... The polymer material with lowest loss is Topas and all the solid core fibers are manufactured using this material. The polymer PMMA however has higher refractive index along with higher loss, and this higher refractive index is utilized to achieve a large bandwidth hollow core fiber with a low air......Terahertz radiation offers many exciting applications noticeably in spectroscopy and it is showing promising results in imaging, mainly for security applications. In this project the study of using structured polymer fibers for THz waveguiding is presented. The inspiration for the THz fiber...

  14. Phthalocyanine polymers

    Science.gov (United States)

    Achar, B. N.; Fohlen, G. M.; Parker, J. A. (Inventor)

    1985-01-01

    A method of forming 4,4',4'',4''' -tetraamino phthalocyanines involves reducing 4,4',4'',4''' -tetranitro phthalocyanines, polymerizing the metal tetraamino phthalocyanines with a tetracarboxylic dianhydride (preferably aromatic) or copolymerizing with a tetracarboxylic dianhydride and a diamine (preferably also aromatic) to produce amic acids which are then dehydrocyclized to imides. Thermally and oxidatively stable polymers result which form tough, flexible films, varnishes, adhesives, and fibers.

  15. 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.

  16. Nanomodified polymer composites: Thermophysical and physico-mechanical properties

    Science.gov (United States)

    Shchegolkov, Alexander; Shchegolkov, Alexey; Dyachkova, Tatyana; Borovskikh, Pavel

    2017-11-01

    The paper presents the results of investigation of thermophysical and physicomechanical properties of polymer-based composites modified with paraffin and carbon nanotubes (CNTs) mixture. Thermal conductivity of composites based on polyethylene, fluoroplastic, polyvinyl chloride (PVC) is 0.48, 0.42 and 0.36 W/(m.°C), respectively, compared to thermal conductivity of pure paraffin - 0.25 W/(m.°C). It has been revealed that for materials heat capacity the polymer matrix determines the position of the maximum point on temperature dependence having extreme nature. Temperature changes in composites volume do not exceed 3% from the initial state to the phase transition, that allows them to be used in a combination with other materials.

  17. Preparation of graphene/polymer composite photocathode for QDSSC

    Science.gov (United States)

    Wang, Qiandi; Shen, Yue; Tan, Jie; Xu, Kai; Shen, Tan; Cao, Meng; Gu, Feng; Wang, Linjun

    2013-12-01

    Graphene (rGO) was fabricated by modified Hummers method and a reducing process. Conductive polymer/graphene films were obtained by scalpel technology and used as photocathode in CdS quantum dot-sensitized solar cell (QDSSC). Polymers used in this paper were ethyl cellulose (EC), polyphenyl vinyl (PPV) and polyvinyl butyral (PVB), respectively. The obtained composite films were investigated by X-ray diffraction, Raman spectroscopy technology and scanning electron microscope (SEM). The photoelectric properties of QDSSCs were tested under AM 1.5 irradiation. Test results show that the film performance of the EC/rGO and PPV/rGO photocathode have been improved effectively. Power conversion efficiency (PCE) of the relative QDSSCs under AM 1.5 irradiation were 0.81% and 0.86%, respectively.

  18. 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

    OpenAIRE

    U. Bunyatova; Z. M. O. Rzayev; M. Simsek

    2016-01-01

    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 ...

  19. Application of Polyelectrolyte Complex Nanoparticles in Increasing the Lifetime of Poly(Vinyl Sulfonate) Scale Inhibitor in Berea Sandstone Rock

    Science.gov (United States)

    Veisi, Masoumeh

    Water flooding is used extensively in oil fields to maintain reservoir pressure and displace oil. However, seawater containing high concentrations of sulfate ion may form scale precipitate when mixed with incompatible formation water containing barium and strontium ions. Formation of scales such as barium sulfate can pose costly operational problems by plugging the injection and production wells. Polymers such as poly(vinyl sulfonate) (PVS) are well-known scale inhibitors which can effectively prevent the formation of barium sulfate. Squeeze treatment is a common method which can be used to inject the PVS in the reservoir. In this process, PVS solution is injected into production wells and the inhibitor is adsorbed on reservoir rocks and released during subsequent production of reservoir fluids. Once inhibitor concentration decreases to its minimum effective concentration (MEC), the process needs to be repeated. However, the low adsorption of PVS onto the rock results in a very short squeeze lifetime rendering the treatment uneconomical. In this research, the application of polyelectrolyte complexes (PECs) to increase the squeeze treatment lifetime of PVS was examined. The objective of the project was to develop PEC nanoparticles (NPs) which would improve the PVS adsorption on the rock through charge alteration. The PECs entrapped the PVS in their structure and released the polymer gradually when pH or ionic strength of the surrounding brine increased. PVS adsorption followed by a slow release of the polymer can maintain the scale inhibitor concentration above MEC for longer, and therefore extend the squeeze treatment lifetime. Positively charged nanoparticles consisting of poly(ethyleneimine) and poly(vinyl sulfonate) (PEI-PVS) were prepared and optimized to maximize PVS entrapment in the PEC structure. The stability of the nanoparticles at different temperatures and over time was confirmed. Their stability in the presence of mono and divalent cations was also

  20. Synthesis and spectroscopic properties of a soluble semiconducting porphyrin polymer.

    Science.gov (United States)

    Schmitz, Robert A; Liddell, Paul A; Kodis, Gerdenis; Kenney, Michael J; Brennan, Bradley J; Oster, Nolan V; Moore, Thomas A; Moore, Ana L; Gust, Devens

    2014-09-07

    A semiconducting porphyrin polymer that is solution processable and soluble in organic solvents has been synthesized, and its spectroscopic and electrochemical properties have been investigated. The polymer consists of diarylporphyrin units that are linked at meso-positions by aminophenyl groups, thus making the porphyrin rings an integral part of the polymer backbone. Hexyl chains on two of the aryl groups impart solubility. The porphyrin units interact only weakly in the ground electronic state. Excitation produces a local excited state that rapidly evolves into a state with charge-transfer character (CT) involving the amino nitrogen and the porphyrin macrocycle. Singlet excitation energy is transferred between porphyrin units in the chain with a time constant of ca. 210 ps. The final CT state has a lifetime of several nanoseconds, and the first oxidation of the polymer occurs at ca. 0.58 V vs. SCE. These properties make the polymer a suitable potential excited state electron donor to a variety of fullerenes or other acceptor species, suggesting that the polymer may find use in organic photovoltaics, sensors, and similar applications.

  1. Composites based on cellulose fiber nonwovens and a water soluble polymer 1. Structure and strength-deformation characteristics of cellulose fiber nonwovens and structural characteristics of the composites

    Science.gov (United States)

    Cerpakovska, D.; Kalnins, M.

    2012-03-01

    The results of a study on the strength-deformation characteristics (tensile elastic modulus, ultimate strength, elongation at break, and punching and tearing strengths) of two kinds of cellulose fiber nonwovens (CFNs) with dissimilar void content and different geometrical parameters of cellulose fibers are discussed. The structural characteristics of composites prepared by impregnation with poly(vinyl alcohol) water solutions are analyzed, too. Composites with volume fractions of polymer up to 0.4% and volume fractions of voids up to 0.3% were prepared. Filling of voids by the polymer occurred without significant changes in the structure of CFNs. The fraction of closed voids increased with polymer content.

  2. Solid-state semiconducting polymer lasers

    Science.gov (United States)

    Hide, Fumitomo

    A comprehensive review of the recent emergence of semiconducting pi-conjugated polymers as solid-state laser materials is presented. With the notable exception of semiconducting polymer laser diodes, high performance photonic and electronic devices have been fabricated from semiconducting polymers, with their performance parameters approaching or even surpassing those of their inorganic counterparts in some cases. As the first step in exploring the feasibility of 'plastic' laser diodes, optically pumped stimulated emission, gain, and lasing have recently been observed in over a dozen different semiconducting polymers representing a variety of molecular structures with emission wavelengths spanning the visible spectrum. Resonant structures for providing the feedback required for lasing or gain narrowing in submicron thick films, neat and undiluted, of photoluminescent thin solid films of conjugated polymers include: planar waveguides, microcavities, distributed feedback (DFB) structures, and high-Q microresonators. Lasing and gain narrowing have been compared using two of these structures: waveguides and microcavities. In both cases, the gain narrowing or lasing threshold is at 0.05-0.1 muJ per 10 ns pulse focused to ˜1.5 mm. Single-mode microcavity lasers are obtained when a microcavity resonance occurs at the wavelength where the gain of the polymer is maximum. High efficiency Stokes-shifted photoluminescence (PL) and high gain are features that make undiluted semiconducting polymers uniquely attractive as solid-state laser materials. These features also make the same polymers attractive as active components in InGaN/semiconducting polymer hybrid LEDs, where the blue emission from the InGaN LED provides the blue component, and simultaneously, serves as the short wavelength pump source for exciting the PL of the polymer film(s). White, green, green-yellow, and yellow emitting InGaN/polymer hybrid LED prototypes have been demonstrated simply by dip-coating pre

  3. CINE: Comet INfrared Excitation

    Science.gov (United States)

    de Val-Borro, Miguel; Cordiner, Martin A.; Milam, Stefanie N.; Charnley, Steven B.

    2017-08-01

    CINE calculates infrared pumping efficiencies that can be applied to the most common molecules found in cometary comae such as water, hydrogen cyanide or methanol. One of the main mechanisms for molecular excitation in comets is the fluorescence by the solar radiation followed by radiative decay to the ground vibrational state. This command-line tool calculates the effective pumping rates for rotational levels in the ground vibrational state scaled by the heliocentric distance of the comet. Fluorescence coefficients are useful for modeling rotational emission lines observed in cometary spectra at sub-millimeter wavelengths. Combined with computational methods to solve the radiative transfer equations based, e.g., on the Monte Carlo algorithm, this model can retrieve production rates and rotational temperatures from the observed emission spectrum.

  4. Radiation crosslinking of starch/water-soluble polymer blends for hydrogel

    Energy Technology Data Exchange (ETDEWEB)

    Hashim, K.; Mohid, N.; Bahari, K.; Dahlan, K.Z. [Radiation Processing Technology Division, Malaysian Institute Nuclear Technology Research Malaysia (MINT), Bangi, 43000 Kajang (Malaysia)

    2000-03-01

    Water-soluble polymers such as PVP(polyvinyl pyrrolidone) and PVA(polyvinyl alcohol), in aqueous solution can form hydrogel easily upon gamma or electron beam irradiation. The properties of hydrogels, particularly for wound dressing application, can be further improved by adding sago starch to the blend. Results show improved gel strength and elongation properties of the hydrogel with increasing sago concentration. It was found that the PVA/sago hydrogel gives better gel strength and elongation than the PVP/sago hydrogel. The tackiness property of the PVA/sago hydrogel increased with increase amount of sago starch added. In case of PVP/sago hydrogel, the tackiness property shows significant increase with increasing amount of sago except for the 5%PVP composition. The swelling properties of PVP/sago and PVA/sago hydrogel decreased with increasing amount of sago but the crosslink density of the hydrogels also reduced. (author)

  5. Small nanosized poly(vinyl benzyl trimethylammonium chloride) based polyplexes for siRNA delivery

    NARCIS (Netherlands)

    Lou, Bo|info:eu-repo/dai/nl/37052537X; Beztsinna, Nataliia|info:eu-repo/dai/nl/411277928; Mountrichas, Grigoris; van den Dikkenberg, Joep B.|info:eu-repo/dai/nl/304841420; Pispas, Stergios; Hennink, Wim E.|info:eu-repo/dai/nl/070880409

    2017-01-01

    The success of siRNA gene therapy requires the availability of safe and efficient delivery systems. In the present study, we investigated poly(vinyl benzyl trimethylammonium chloride) (PVTC) and its block copolymer with poly(oligo(ethyleneglycol) methacrylate) (POEGMA) as delivery vector for siRNA.

  6. Structure of Hybrid Interpolymeric Complexes of Polyvinyl Alcohol and Halides of Second Group Elements

    Directory of Open Access Journals (Sweden)

    I. Yu. Prosanov

    2017-01-01

    Full Text Available Density functional theory was used to investigate structure and properties of polyvinyl alcohol complexes with halides of second group elements XHal2 (X = Be, Mg, Ca, Zn, Sr, Cd, Ba, and Hg; Hal = F, Cl, Br, and I. PVA can form hybrid interpolymeric complexes with some of them. These complexes show double spiral structure of two types.

  7. Linear Dichroism of Cyanine Dyes in Stretched Polyvinyl Alcohol Films: A Physical Chemistry Laboratory Experiment.

    Science.gov (United States)

    Natarajan, L. V.; And Others

    1983-01-01

    Provides background information, procedures, and results of an undergraduate physical chemistry experiment on the polarization of absorption spectra of cyanine dyes in stretched polyvinyl alcohol films. The experiment gives a simple demonstration of the concept of linear dichromism and the validity of the TEM method used in the analyses. (JN)

  8. Stabilization of individual tubular J-aggregates by poly(vinyl alcohol)

    NARCIS (Netherlands)

    von Berlepsch, H; Kirstein, S; Hania, R; Didraga, C; Pugzlys, A; Bottcher, C

    2003-01-01

    The changes in the optical properties and morphology of J-aggregates fonned by the 3,3'-bis(3-carboxypropyl)5,5',6,6'-tetrachloro-1,1'-dioctylbenzimidacarbocyanine dye (C8O3) in aqueous solution that are induced by the addition of poly(vinyl alcohol) (PVA) were investigated by optical spectroscopy

  9. The Rheological Properties of Poly(Vinyl Alcohol) Gels from Rotational Viscometry

    Science.gov (United States)

    Hurst, Glenn A.; Bella, Malika; Salzmann, Christoph G.

    2015-01-01

    A laboratory experiment was developed to follow the gelation of a polyvinyl alcohol (PVA) solution upon addition of borax by using rotational viscometry. The rheological properties of the gel were examined, measuring the dependence of viscosity and shear stress on the shear rate. Time-dependent studies were also conducted in which the viscosity of…

  10. Chain length effect on dynamical structure of poly(vinyl pyrrolidone ...

    Indian Academy of Sciences (India)

    Chain length effect on dynamical structure of poly(vinyl pyrrolidone)–polar solvent mixtures in dilute solution of dioxane studied by microwave dielectric relaxation measurement. R J SENGWA∗ and SONU SANKHLA. Microwave Research Laboratory, Department of Physics, J N V University,. Jodhpur 342 005, India.

  11. The influence of physical ageing on yielding and failure of unplasticised poly(vinyl chloride) pipes

    NARCIS (Netherlands)

    Visser, Roy; Bor, Teunis Cornelis; Wolters, Mannes; Govaert, Leon E.

    2009-01-01

    Physical ageing can cause significant changes of the mechanical properties of unplasticised poly(vinyl chloride) pipes during service life. A model is presented which incorporates these changes and can predict long-term failure times quantitatively, based on short term tests

  12. Templated diamond growth on porous carbon foam decorated with polyvinyl alcohol-nanodiamond composite

    Czech Academy of Sciences Publication Activity Database

    Varga, Marián; Stehlík, Štěpán; Kaman, Ondřej; Ižák, Tibor; Domonkos, Mária; Lee, D.S.; Kromka, Alexander

    2017-01-01

    Roč. 119, Aug (2017), s. 124-132 ISSN 0008-6223 R&D Projects: GA ČR GC15-22102J Institutional support: RVO:68378271 Keywords : nucleation * polyvinyl alcohol * nanodiamonds * carbon foam Subject RIV: JJ - Other Materials Impact factor: 6.337, year: 2016

  13. Film dosimeters based on methylene blue and methyl orange in polyvinyl alcohol

    DEFF Research Database (Denmark)

    Chung, W.H.; Miller, A.

    1994-01-01

    Polyvinyl alcohol (PVA) films containing methylene blue and methyl orange are useful as gamma and electron radiation dosimeters. Absorbed doses should not exceed 40 kGy for methylene blue and 500 kGy for methyl orange. Because PVA is water-soluble, the films may be made without toxic solvents...

  14. Properties of polyvinyl alcohol/xylan composite films with citric acid.

    Science.gov (United States)

    Wang, Shuaiyang; Ren, Junli; Li, Weiying; Sun, Runcang; Liu, Shijie

    2014-03-15

    Composite films of xylan and polyvinyl alcohol were produced with citric acid as a new plasticizer or a cross-linking agent. The effects of citric acid content and polyvinyl alcohol/xylan weight ratio on the mechanical properties, thermal stability, solubility, degree of swelling and water vapor permeability of the composite films were investigated. The intermolecular interactions and morphology of composite films were characterized by FTIR spectroscopy and SEM. The results indicated that polyvinyl alcohol/xylan composite films had good compatibility. With an increase in citric acid content from 10% to 50%, the tensile strength reduced from 35.1 to 11.6 MPa. However, the elongation at break increased sharply from 15.1% to 249.5%. The values of water vapor permeability ranged from 2.35 to 2.95 × 10(-7)g/(mm(2)h). Interactions between xylan and polyvinyl alcohol in the presence of citric acid become stronger, which were caused by hydrogen bond and ester bond formation among the components during film forming. Copyright © 2013. Published by Elsevier Ltd.

  15. Hydroxyapatite nanoparticles: electrospinning and calcination of hydroxyapatite/polyvinyl butyral nanofibers and growth kinetics

    NARCIS (Netherlands)

    Zakaria, S.M.; Zein, S.H. Sharif; Othman, M.R.; Jansen, J.A.

    2013-01-01

    Electrospinning of hydroxyapatite (HA)/polyvinyl butyral solution resulted in the formation of fibers with average diameter of 937-1440 nm. These fibers were converted into HA nanoparticles with size <100 nm after undergoing calcination treatment at 600 degrees C. The diameter of the fiber was

  16. Disk Refining and Ultrasonication Treated Sugarcane Bagasse Residues for Poly(Vinyl Alcohol) Bio-composites

    Science.gov (United States)

    Qingzheng Cheng; Zhaohui Tong; Luisa Dempere; Lonnie Ingram; Letian Wang; J.Y. Zhu

    2013-01-01

    Disk refining and ultrasonication treated sugarcane bagasse residues reclaimed from the waste stream of a simplified bioethanol process after fermentation were used to fabricate biobased composites with poly(vinyl alcohol) (PVA) by film casting. The morphologies and the size distributions of residue particles were characterized by scanning electronic microscopy and...

  17. Conversion of chlorinated waste streams from the production of polyvinyl chloride over La-based catalysts

    NARCIS (Netherlands)

    van der Heijden, A.W.A.M.|info:eu-repo/dai/nl/304841412

    2008-01-01

    Annually, more than one third of all chlorine consumption is used for the production of C2H3Cl. This is the monomer for the production of polyvinyl chloride (PVC). Even though the production process of C2H3Cl is rather selective, by-products are formed in large amounts due to the large scale of the

  18. Plasticizers increase adhesion of the deteriogenic fungus Aureobasidium pullulans to polyvinyl chloride

    NARCIS (Netherlands)

    Webb, JS; Van der Mei, HC; Nixon, M; Eastwood, IM; Greenhalgh, M; Read, SJ; Robson, GD; Handley, PS

    Initial adhesion of fungi to plasticized polyvinyl chloride (pPVC) may determine subsequent colonization and biodeterioration processes. The deteriogenic fungus Aureobasidium pullulans was used to investigate the physicochemical nature of adhesion to both unplasticized PVC (uPVC) and pPVC containing

  19. Modeling of the Migration of Glycerol Monoester Plasticizers in Highly Plasticized Poly(vinyl chloride)

    DEFF Research Database (Denmark)

    Lundsgaard, Rasmus; Kontogeorgis, Georgios; Kristiansen, Jørgen K.

    2009-01-01

    soybean oil (ESBO) with regard to their migration from three different types of poly(vinyl chloride) into isooctane at 20, 40, and 60 degrees C. Diffusion coefficients derived from the experimental migration data were evaluated against diffusion coefficients estimated from a model based solely...

  20. Synthesis of MoO3 and its polyvinyl alcohol nanostructured film

    Indian Academy of Sciences (India)

    The solvent casting method is adopted for the synthesis of MoO3 dispersed polyvinyl alcohol nanostructured film (MoO3–PVA). These synthesized MoO3 and their composite samples are characterized for their structure, morphology, bonding and thermal behaviour by XRD, SEM, IR and DSC techniques, respectively.

  1. Properties of poly(vinyl alcohol)–borax gel doped with neodymium ...

    Indian Academy of Sciences (India)

    Abstract. Neodymium and praseodymium ions, singly and in combination, have been doped into a poly(vinyl alcohol)–borax matrix. X-ray diffraction shows structural correlations from 2 to 6 Е and 15 Е, while small angle neutron scattering indicates that the rare-earth ions do not affect the nanoscale structures of the gels.

  2. Clinical Fit of Partial Removable Dental Prostheses Based on Alginate or Polyvinyl Siloxane Impressions.

    NARCIS (Netherlands)

    Fokkinga, W.A.; Witter, D.J.; Bronkhorst, E.M.; Creugers, N.H.J.

    2017-01-01

    PURPOSE: The aim of this study was to analyze the clinical fit of metal-frame partial removable dental prostheses (PRDPs) based on custom trays used with alginate or polyvinyl siloxane impression material. MATERIALS AND METHODS: Fifth-year students of the Nijmegen Dental School made 25 correct

  3. Oxidative mineralization and characterization of polyvinyl alcohol for compatibility with tank farm processing chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Oji, L.N.

    2000-01-04

    Polyvinyl alcohol (PVA) material has been evaluated for use as a cost-effective substitute for conventional cellulose-based disposal materials (decontamination mops and wipes), plastic bags, and disposable personal protection clothing, that are currently used at Savannah River Site. This study also provides process design criteria for ultraviolet/ultrasonic/hydrogen peroxide PVA reactor system.

  4. Nanofibrillated cellulose (NFC) reinforced polyvinyl alcohol (PVOH) nanocomposites: properties, solubility of carbon dioxide, and foaming

    Science.gov (United States)

    Yottha Srithep; Lih-Sheng Turng; Ronald Sabo; Craig Clemons

    2012-01-01

    Polyvinyl alcohol (PVOH) and its nanofibrillated cellulose (NFC) reinforced nanocomposites were produced and foamed and its properties-such as the dynamic mechanical properties, crystallization behavior, and solubility of carbon dioxide (CO2)were evaluated. PVOH was mixed with an NFC fiber suspension in water followed by casting. Transmission...

  5. Clinical Fit of Partial Removable Dental Prostheses Based on Alginate or Polyvinyl Siloxane Impressions.

    Science.gov (United States)

    Fokkinga, Wietske A; Witter, Dick J; Bronkhorst, Ewald M; Creugers, Nico H

    The aim of this study was to analyze the clinical fit of metal-frame partial removable dental prostheses (PRDPs) based on custom trays used with alginate or polyvinyl siloxane impression material. Fifth-year students of the Nijmegen Dental School made 25 correct impressions for 23 PRDPs for 21 patients using alginate, and 31 correct impressions for 30 PRDPs for 28 patients using polyvinyl siloxane. Clinical fit of the framework as a whole and of each retainer separately were evaluated by calibrated supervisors during framework try-in before (first evaluation) and after (second evaluation) possible adjustments (score 0 = poor fit, up to score 3 = good fit). Framework fit and fit of the denture base were evaluated at delivery (third evaluation). Finally, postinsertion sessions were evaluated and total number of sessions needed, sore spots, adjustments to the denture base, and reported food-impaction were recorded. No significant differences in clinical fit (of the framework as a whole, for the retainers, or for the denture base) were found between the groups in the three evaluation sessions. Differences were not found for postinsertion sessions with one exception: in the alginate group, four subjects reported food impaction, versus none in the polyvinyl siloxane group. Clinical fit of metal-frame PRDPs based on impressions with custom trays combined with alginate or polyvinyl siloxane was similar.

  6. Oxidative Mineralization and Characterization of Polyvinyl Alcohol Solutions for Wastewater Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Oji, L.N.

    1999-08-31

    The principal objectives of this study are to identify an appropriate polyvinyl alcohol (PVA) oxidative mineralization technique, perform compatibility and evaporation fate tests for neat and mineralized PVA, and determine potential for PVA chemical interferences which may affect ion exchange utilization for radioactive wastewater processing in the nuclear industry.

  7. Compatibility of Polyvinyl Alcohol with the 241-F/H Tank Farm Liquid Waste

    Energy Technology Data Exchange (ETDEWEB)

    Oji, L.N.

    1998-11-25

    This report describes results from laboratory-scale oxidative mineralization of polyvinyl alcohol (PVA), and the evaluation of the F/H Tank Farms as a storage/disposal option for PVA waste solution generated in the Canyons and B-line decontamination operations.

  8. Tunable Optical Polymer Systems

    National Research Council Canada - National Science Library

    Jenekhe, S. A; Bard, Allen J; Chen, S. H; Hammond, P. T; Rothberg, L. J

    2004-01-01

    .... The synthesis and properties of new electrochromic polymers are described. Electrochromic devices incorporating conjugated polymers have been fabricated and found to be durable past 100,000 cycles...

  9. Subsurface excitations in a metal

    DEFF Research Database (Denmark)

    Ray, M. P.; Lake, R. E.; Sosolik, C. E.

    2009-01-01

    We investigate internal hot carrier excitations in a Au thin film bombarded by hyperthermal and low energy alkali and noble gas ions. Excitations within the thin film of a metal-oxide-semiconductor device are measured revealing that ions whose velocities fall below the classical threshold given...... by the free-electron model of a metal still excite hot carriers. Excellent agreement between these results and a nonadiabatic model that accounts for the time-varying ion-surface interaction indicates that the measured excitations are due to semilocalized electrons near the metal surface....

  10. Surface characterization of poly(vinyl chloride) urinary catheters functionalized with acrylic acid and poly(ethylene glycol) methacrylate using gamma-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Islas, Luisa [Departamento de Química de Radiaciones y Radioquímica, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico D.F. 04510 (Mexico); Ruiz, Juan-Carlos [División de Ciencias Básicas e Ingeniería, Depto. de Ingeniería de Procesos e Hidráulica, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco No. 186, 09340 México D.F. (Mexico); Muñoz-Muñoz, Franklin [Facultad de Ingeniería, Arquitectura y Diseño, Universidad Autónoma de Baja California, Carretera Transpeninsular Ensenada-Tijuana 3917, Ensenada, B.C. C.P 22860 (Mexico); Isoshima, Takashi [Nano Medical Engineering Laboratory, RIKEN, 2-1Hirosawa, Wako, Saitama 351-0198 (Japan); Burillo, Guillermina, E-mail: burillo@nucleares.unam.mx [Departamento de Química de Radiaciones y Radioquímica, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico D.F. 04510 (Mexico)

    2016-10-30

    Highlights: • Polymer grafting using gamma-radiation allowed for acrylic acid and poly(ethylene glycol) methacrylate to graft on the inner and outer surface of poly(vinyl chloride) urinary catheters. • HR-XPS revealed the different compositional percentages of the compounds present on the surface of the catheter. • Catheters that were grafted with PEGMA had the roughest surface as observed using scanning electron microscopy (SEM) and confocal laser microscopy (CLM). - Abstract: Poly(vinyl chloride) (PVC) urinary catheters were modified with either a single or binary graft of acrylic acid (AAc) and/or poly(ethylene glycol) methacrylate (PEGMA) using gamma-radiation from {sup 60}Co to obtain PVC-g-AAc, PVC-g-PEGMA, [PVC-g-AAc]-g-PEGMA, and [PVC-g-PEGMA]-g-AAc copolymers. The outer and inner surfaces of the modified catheters were characterized using scanning electron microscopy (SEM), confocal laser microscopy (CLM) and X-ray photoelectron spectroscopy (XPS). The XPS analyses, by examining the correlation between the variation of the C{sub 1s} and O{sub 1s} content at the catheter’s surface, revealed that the catheter’s surfaces were successfully grafted with the chosen compounds, with those that were binary grafted showing a slightly more covered surface as was evidenced by the disappearance of PVC’s Cl peak. The SEM and CLM analyses revealed that catheters that had been grafted with PEGMA had a rougher outer surface as compared to those that had only been grafted with AAc. In addition, these imaging techniques showed that the inner surface of the singly grafted catheters, whether they had been grafted with AAc or PEGMA, retained some smoothness at the analyzed grafting percentages, while the binary grafted catheters showed many protuberances and greater roughness on both outer and inner surfaces.

  11. From Commodity Polymers to Functional Polymers

    OpenAIRE

    Tao Xiang,; Ling-Ren Wang; Lang Ma; Zhi-Yuan Han; Rui Wang; Chong Cheng; Yi Xia; Hui Qin; Chang-Sheng Zhao

    2014-01-01

    Functional polymers bear specified chemical groups, and have specified physical, chemical, biological, pharmacological, or other uses. To adjust the properties while keeping material usage low, a method for direct synthesis of functional polymers is indispensable. Here we show that various functional polymers can be synthesized by in situ cross-linked polymerization/copolymerization. We demonstrate that the polymers synthesized by the facile method using different functional monomers own outs...

  12. Photoluminescent supramolecular hyperbranched polymer without conventional chromophores based on inclusion complexation.

    Science.gov (United States)

    Li, Wenyu; Qu, Jiale; Du, Jianwei; Ren, Kefeng; Wang, Youxiang; Sun, Jingzhi; Hu, Qiaoling

    2014-08-28

    A novel photoluminescent supramolecular hyperbranched polymer (SHP) without conventional chromophores was constructed for the first time by inclusion complexation between α-cyclodextrin and diethylenetriamine. The SHP showed wide-band fluorescence dependent upon the excitation wavelength.

  13. Axonal Excitability in Amyotrophic Lateral Sclerosis : Axonal Excitability in ALS.

    Science.gov (United States)

    Park, Susanna B; Kiernan, Matthew C; Vucic, Steve

    2017-01-01

    Axonal excitability testing provides in vivo assessment of axonal ion channel function and membrane potential. Excitability techniques have provided insights into the pathophysiological mechanisms underlying the development of neurodegeneration and clinical features of amyotrophic lateral sclerosis (ALS) and related neuromuscular disorders. Specifically, abnormalities of Na+ and K+ conductances contribute to development of membrane hyperexcitability in ALS, thereby leading to symptom generation of muscle cramps and fasciculations, in addition to promoting a neurodegenerative cascade via Ca2+-mediated processes. Modulation of axonal ion channel function in ALS has resulted in significant symptomatic improvement that has been accompanied by stabilization of axonal excitability parameters. Separately, axonal ion channel dysfunction evolves with disease progression and correlates with survival, thereby serving as a potential therapeutic biomarker in ALS. The present review provides an overview of axonal excitability techniques and the physiological mechanisms underlying membrane excitability, with a focus on the role of axonal ion channel dysfunction in motor neuron disease and related neuromuscular diseases.

  14. Degradation of polyvinyl alcohol (PVA) by homogeneous and heterogeneous photocatalysis applied to the photochemically enhanced Fenton reaction.

    Science.gov (United States)

    Bossmann, S H; Oliveros, E; Göb, S; Kantor, M; Göppert, A; Lei, L; Yue, P L; Braun, A M

    2001-01-01

    The reaction mechanism of the oxidative degradation of polyvinyl alcohol (PVA) by the photochemically enhanced Fenton reaction was studied using a homogeneous (Fe2+(aq) + H2O2) and a heterogeneous reaction system (iron(III)-exchanged zeolite Y+ H2O2). In the homogeneous Fenton system, efficient degradation was observed in a batch reactor, equipped with a medium pressure mercury arc in a Pyrex envelope and employing 80% of the stoichiometric amount of H2O2 required for the total oxidation of PVA and a concentration ratio as low as I mole of iron(II) sulfate per 20 moles of PVA sub-units (C2H40). Model PVA polymers of three different molecular weights (15,000, 49,000 and 100,000 g mol(-1)) were found to follow identical degradation patterns. Strong experimental evidence supports the formation of supermacromolecules (MW: 1-5 x 10(6) g/mol) consisting of oxidized PVA and trapped iron(III) at an early reaction stage. Low molecular weight intermediates, such as oxalic acid, formic acid or formaldehyde were not found during PVA degradation in the homogeneous Fenton system, and we may deduce that the manifold of degradation reactions is mainly taking place within the super-macromolecules from which CO2 is directly released. However, in the heterogeneous Fenton system, the reaction behavior was found to be distinctly different: a decrease of the molecular weights of all three tested monodisperse PVA samples was observed by the broadening of the GPC-traces during irradiation, and oxalic acid was formed. The results lead to the mechanistic hypothesis that during the heterogeneous Fenton process, the cleavage of the PVA-chains may occur at random positions, the reactive centres being located inside the iron(III)-doped zeolite Y photocatalysts.

  15. Temperature dependent dielectric and conductivity studies of polyvinyl alcohol-ZnO nanocomposite films by impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hemalatha, K. S.; Damle, R.; Rukmani, K., E-mail: rukmani9909@yahoo.co.in [Department of Physics, Bangalore University, Bangalore 560056 (India); Sriprakash, G. [Department of Physics, Maharani' s Science College for Women, Bangalore 560001 (India); Ambika Prasad, M. V. N. [Department of Physics, Gulbarga University, Gulbarga 585106 (India)

    2015-10-21

    Dielectric and conductivity behaviors of nano ZnO doped polyvinyl alcohol (PVA) composites for various concentrations of dopant were investigated using impedance spectroscopy for a wide range of temperatures (303 K–423 K) and frequencies (5 Hz–30 MHZ). The dielectric properties of host polymer matrix have been improved by the addition of nano ZnO and are found to be highly temperature dependent. Anomalous dielectric behavior was observed in the frequency range of 2.5 MHz–5 MHz. Increase in dielectric permittivity and dielectric loss was observed with respect to temperature. The Cole-Cole plot could be modeled by low resistance regions in a high resistance matrix and the lowest resistance was observed for the 10 mol. % films. The imaginary part of the electric modulus showed asymmetric peaks with the relaxation following Debye nature below and non-Debye nature above the peaks. The ac conductivity is found to obey Jonscher's power law, whereas the variation of dc conductivity with temperature was found to follow Arrhenius behavior. Two different activation energy values were obtained from Arrhenius plot indicating that two conduction mechanisms are involved in the composite films. Fitting the ac conductivity data to Jonscher's law indicates that large polaron assisted tunneling is the most likely conduction mechanism in the composites. Maximum conductivity is observed at 423 K for all the samples and it is optimum for 10 mol. % ZnO doped PVA composite film. Significant increase in dc and ac conductivities in these composite films makes them a potential candidate for application in electronic devices.

  16. In vitro and in vivo evaluation of blood coagulation activation of polyvinyl alcohol hydrogel plus dextran-based vascular grafts.

    Science.gov (United States)

    Alexandre, Nuno; Costa, Elísio; Coimbra, Susana; Silva, Alice; Lopes, Ascensão; Rodrigues, Miguel; Santos, Marta; Maurício, Ana Colette; Santos, José Domingos; Luís, Ana Lúcia

    2015-04-01

    Polyvinyl alcohol hydrogel (PVA) is a water-soluble synthetic polymer that is commonly used in biomedical applications including vascular grafting. It was argued that the copolymerization of PVA with dextran (Dx) can result in improvement of blood-biomaterial interactions. The focus of this experimental study was to assess that interaction through an in vivo and in vitro evaluation of the coagulation system activation. The thrombogenicity of the copolymer was determined by quantification of platelet adhesion through the lactate dehydrogenase assay, determination of whole blood clotting time, and by quantification of platelet activation by flow cytometry. The thrombin-antithrombin complex blood levels were also determined. The obtained results for the in vitro assays suggested a non-thrombogenic profile for PVA/Dx. Additionally in vivo coagulation and hematological parameters were determined in an animal model after PVA/Dx vascular graft implantation. For coagulation homeostasis assessment, the intrinsic and extrinsic pathway's activation was determined by measuring prothrombin time (PT) and activated partial thromboplastin time (aPTT). Other markers of coagulation and inflammation activation including d-dimers, interleukin-6, and C-reactive protein were also assessed. The PVA/Dx copolymer tended to inhibit platelet adhesion/activation process and the contact activation process for coagulation. These results were also confirmed with the in vivo experiments where the measurements for APTT, interleukin-6, and C-reactive protein parameters were normal considering the species normal range of values. The response to those events is an indicator of the in vitro and in vivo hemocompatibility of PVA/Dx and it allows us to select this biomaterial for further preclinical trials in vascular reconstruction. © 2014 Wiley Periodicals, Inc.

  17. Composition Heterogeneity Induced Crystallization in Double Crystalline Binary Polymer Blends

    OpenAIRE

    Dasmahapatra, Ashok Kumar

    2016-01-01

    Polymer blends offer an exciting material for various potential applications due to their tunable properties by varying constituting components and their relative composition. Our simulation results unravel an intrinsic relationship between the phase behavior and crystallization characteristics with the relative composition of A- and B-polymer in the system. We report simulation results for non-isothermal and isothermal crystallization with weak and strong segregation strength to elucidate th...

  18. Indaceno-Based Conjugated Polymers for Polymer Solar Cells.

    Science.gov (United States)

    Yin, Yuli; Zhang, Yong; Zhao, Liancheng

    2018-01-04

    Polymer solar cells have received considerable attention due to the advantages of low material cost, tunable band gaps, ultralight weight, and high flexible properties, and they have been a promising organic photovoltaic technology for alternative non-renewable fossil fuels for the past decade. Inspired by these merits, numerous state-of-the-art organic photovoltaic materials have been constructed. Among them, indaceno-based polymer materials have made an impact in obtaining an impressive power conversion efficiency of more than 11%, which shows the momentous potential of this class of materials for commercial applications. In this review, recent progress of indaceno-based organic polymer solar cells are reviewed, and the structure-property device performance correlations of the reported materials are highlighted. Then, common regularities of these successful cases are collected, and encouraging viewpoints on the further development of more exciting indaceno-based organic photovoltaic materials are provided. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. From Commodity Polymers to Functional Polymers

    Science.gov (United States)

    Xiang, Tao; Wang, Ling-Ren; Ma, Lang; Han, Zhi-Yuan; Wang, Rui; Cheng, Chong; Xia, Yi; Qin, Hui; Zhao, Chang-Sheng

    2014-01-01

    Functional polymers bear specified chemical groups, and have specified physical, chemical, biological, pharmacological, or other uses. To adjust the properties while keeping material usage low, a method for direct synthesis of functional polymers is indispensable. Here we show that various functional polymers can be synthesized by in situ cross-linked polymerization/copolymerization. We demonstrate that the polymers synthesized by the facile method using different functional monomers own outstanding pH-sensitivity and pH-reversibility, antifouling property, antibacterial, and anticoagulant property. Our study opens a route for the functionalization of commodity polymers, which lead to important advances in polymeric materials applications. PMID:24710333

  20. Topological excitations in magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Bazeia, D., E-mail: bazeia@fisica.ufpb.br [Departamento de Física, Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil); Doria, M.M. [Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro (Brazil); Dipartimento di Fisica, Università di Camerino, I-62032 Camerino (Italy); Rodrigues, E.I.B. [Departamento de Física, Universidade Federal da Paraíba, 58051-970 João Pessoa, PB (Brazil)

    2016-05-20

    In this work we propose a new route to describe topological excitations in magnetic systems through a single real scalar field. We show here that spherically symmetric structures in two spatial dimensions, which map helical excitations in magnetic materials, admit this formulation and can be used to model skyrmion-like structures in magnetic materials.

  1. Erosion Results of the MISSE 7 Polymers Experiment and Zenith Polymers Experiment After 1.5 Years of Space Exposure

    Science.gov (United States)

    De Groh, Kim K.; Banks, Bruce A.; Yi, Grace T.; Haloua, Athena; Imka, Emily C.; Mitchell, Gianna G.; Asmar, Olivia C.; Leneghan, Halle A.; Sechkar, Edward A.

    2016-01-01

    Polymers and other oxidizable materials on the exterior of spacecraft in the low Earth orbit (LEO) space environment can be eroded due to reaction with atomic oxygen (AO). Therefore, in order to design durable spacecraft it is important to know the LEO AO erosion yield (E(sub y), volume loss per incident oxygen atom) of materials susceptible to AO reaction. Two spaceflight experiments, the Polymers Experiment and the Zenith Polymers Experiment, were developed to determine the AO E(sub y) of various polymers flown in ram, wake or zenith orientations in LEO. These experiments were flown as part of the Materials International Space Station Experiment 7 (MISSE 7) mission for 1.5 years on the exterior of the International Space Station (ISS). The experiments included Kapton H(TradeMark) witness samples for AO fluence determination in ram and zenith orientations. The Polymers Experiment also included samples to determine whether AO erosion of high and low ash containing polymers is dependent on fluence. This paper provides an overview of the MISSE 7 mission, a description of the flight experiments with details on the polymers flown, the characterization techniques used, the AO fluence for each exposure orientation, and the LEO E(sub y) results. The E(sub y) values ranged from 7.99x10(exp -28)cu cm/atom for TiO2/Al2O3 coated Teflon(TradeMark) fluorinated ethylene propylene (FEP) flown in the ram orientation to 1.22x10(exp -23cu cm/atom for polyvinyl alcohol (PVOH) flown in the zenith orientation. The E(sub y) of similar samples flown in different orientations has been compared to help determine solar exposure and associated heating effects on AO erosion. The E(sub y) data from these ISS spaceflight experiments provides valuable information for LEO spacecraft design purposes.

  2. Polymer gel dosimeters with PVA-GA matrix.

    Science.gov (United States)

    Abtahi, Seyed Mohammad Mahdi; Sadeghi Abandansari, Hamid

    2017-09-01

    Properties of a new polymer gel with cross-linked polyvinyl alcohol as a gelatinous matrix were investigated. The new polymer gel dosimeter was named PVABAT. The irradiation was performed using a calibrated 60Co beam. The dose responses of the PVABAT formulations were quantified with MRI transverse relaxation rate (R2) measurements. The results show that the PVABAT gel responds linearly to the absorbed dose for doses from 30 up to 45 Gy. The maximal amount of [Formula: see text] of PVABAT polymer gel dosimeter was about 0.19 Gy which was indicated on a better resolution in comparison with previously reported acrylamide-based polymer gel dosimeters formulations. Furthermore, the gel response remains stable in the investigated time (192 h) after the irradiation. The effective atomic number and electron density of the new gel showed a maximum difference of 3.2 and 2% with soft tissue respectively. The melting point also increased significantly for new formulation. Furthermore, the new gel formulation has an elemental tissue equivalency for dosimetry applications involving nuclear reactions.

  3. Identification of different type of polymers in plastics waste.

    Science.gov (United States)

    Siddiqui, Mohammad N; Gondal, Mohammad A; Redhwi, Halim H

    2008-09-01

    The main goal of this work was to develop and test advanced techniques for the instant identification of different type of polymers in post-consumer plastics. In order to accomplish this task, infrared (IR), X-ray diffraction (XRD), differential scanning calorimetric (DSC) and laser induced breakdown spectroscopic (LIBS) techniques were applied. The following six model plastics were identified in this study. Low-density polyethylene (LDPE), High-density polyethylene (HDPE), Polypropylenes (PP), Polystyrene (PS), Polyethylene terephthalate (PET) and Polyvinyl chloride (PVC) along with few randomly selected plastics waste such as water bottle and cap, water cups, yogurt container and coke bottle were studied. IR has shown the fingerprinting of polymer types present in plastics waste. The XRD analysis helps to provide characteristic spectral lines whose intensities vary with the type of each constituent polymer. The DSC method provided the different crystalline melting temperature, glass transition, and onset temperature for the peaks and the percent crystallinity data single out different polymers. The ratio of LIBS signals intensities of carbon and hydrogen atoms were employed for the finger printing of the different family of plastics. The combined use of IR, XRD, DSC and LIBS techniques yielded very useful and effective results for plastic waste management.

  4. 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.

  5. 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.

  6. Synthetic Reference Materials Based on Polymer Films for the Control of Welding Fumes Composition

    Science.gov (United States)

    Kuznetsova, O. V.; Kuznetsova, A. N.; Begunova, L. A.

    2017-04-01

    Analysis of the current hygienic situation in the welding production showed that the intensification of welding processes involves the deterioration of air quality, which negatively affects the welders health. Welders are exposed to a variety of metal fumes, including manganese that may elevate the risk for neurological diseases. The control of metals concentration in the air of the working area is difficult due to the lack of reference materials. The creation of reference materials of welding fumes composition is a challenge due to chemical characteristics of their physical properties. Synthetic samples in a form of the polymer film containing powder particles of welding fumes were create. Studies on the selection of the polymer were done. Experiments proved that the qualitative materials of synthetic welding fumes are obtained by using polyvinyl alcohol. The metals concentration in the samples was determined by X-ray fluorescence analysis. The obtained data demonstrates indirectly the uniform distribution of welding fumes powder particles on the polymer film.

  7. Living Composites of Bacteria and Polymers as Biomimetic Films for Metal Sequestration and Bioremediation.

    Science.gov (United States)

    Knierim, Christian; Enzeroth, Michaela; Kaiser, Patrick; Dams, Christian; Nette, David; Seubert, Andreas; Klingl, Andreas; Greenblatt, Charles L; Jérôme, Valérie; Agarwal, Seema; Freitag, Ruth; Greiner, Andreas

    2015-08-01

    Herein, we report on composite materials of biologically active microorganisms placed in a synthetic polymer matrix. These so-called "living composites" were utilized for gold sequestration (Micrococcus luteus) and bioremediation of nitrite (Nitrobacter winogradskyi) to demonstrate functionality. For the preparation of the living composites the bacteria were first encased in a water-soluble polymer fiber (poly(vinyl alcohol), PVA) followed by coating the fibers with a shell of hydrophobic poly(p-xylylene) (PPX) by chemical vapor deposition (CVD). The combination of bacteria with polymer materials assured the stability and biologically activity of the bacteria in an aqueous environment for several weeks. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Glycoproteins functionalized natural and synthetic polymers for prospective biomedical applications: A review.

    Science.gov (United States)

    Tabasum, Shazia; Noreen, Aqdas; Kanwal, Arooj; Zuber, Mohammad; Anjum, Muhammad Naveed; Zia, Khalid Mahmood

    2017-05-01

    Glycoproteins have multidimensional properties such as biodegradability, biocompatibility, non-toxicity, antimicrobial and adsorption properties; therefore, they have wide range of applications. They are blended with different polymers such as chitosan, carboxymethyl cellulose (CMC), polyvinyl pyrrolidone (PVP), polycaprolactone (PCL), heparin, polystyrene fluorescent nanoparticles (PS-NPs) and carboxyl pullulan (PC) to improve their properties like thermal stability, mechanical properties, resistance to pH, chemical stability and toughness. Considering the versatile charateristics of glycoprotein based polymers, this review sheds light on synthesis and characterization of blends and composites of glycoproteins, with natural and synthetic polymers and their potential applications in biomedical field such as drug delivery system, insulin delivery, antimicrobial wound dressing uses, targeting of cancer cells, development of anticancer vaccines, development of new biopolymers, glycoproteome research, food product and detection of dengue glycoproteins. All the technical scientific issues have been addressed; highlighting the recent advancement. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Experimental Investigation of Mechanical Properties of PVC Polymer under Different Heating and Cooling Conditions

    Directory of Open Access Journals (Sweden)

    Sarkawt Rostam

    2016-01-01

    Full Text Available Due to a widely increasing usage of polymers in various industrial applications, there should be a continuous need in doing research investigations for better understanding of their properties. These applications require the usage of the polymer in different working environments subjecting the material to various temperature ranges. In this paper, an experimental investigation of mechanical properties of polyvinyl chloride (PVC polymer under heating and cooling conditions is presented. For this purpose standard samples are prepared and tested in laboratory using universal material testing apparatus. The samples are tested under different conditions including the room temperature environment, cooling in a refrigerator, and heating at different heating temperatures. It is observed that the strength of the tested samples decreases with the increasing of heating temperature and accordingly the material becomes softer. Meanwhile the cooling environments give a clear increasing to the strength of the material.

  10. Liquid scintillators with near infrared emission based on organoboron conjugated polymers.

    Science.gov (United States)

    Tanaka, Kazuo; Yanagida, Takayuki; Yamane, Honami; Hirose, Amane; Yoshii, Ryousuke; Chujo, Yoshiki

    2015-11-15

    The organic liquid scintillators based on the emissive polymers are reported. A series of conjugated polymers containing organoboron complexes which show the luminescence in the near infrared (NIR) region were synthesized. The polymers showed good solubility in common organic solvents. From the comparison of the luminescent properties of the synthesized polymers between optical and radiation excitation, similar emission bands were detected. In addition, less significant degradation was observed. These data propose that the organoboron conjugated polymers are attractive platforms to work as an organic liquid scintillator with the emission in the NIR region. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Fault Diagnosis Method on Polyvinyl Chloride Polymerization Process Based on Dynamic Kernel Principal Component and Fisher Discriminant Analysis Method

    Directory of Open Access Journals (Sweden)

    Shu-zhi Gao

    2016-01-01

    Full Text Available In view of the fact that the production process of Polyvinyl chloride (PVC polymerization has more fault types and its type is complex, a fault diagnosis algorithm based on the hybrid Dynamic Kernel Principal Component Analysis-Fisher Discriminant Analysis (DKPCA-FDA method is proposed in this paper. Kernel principal component analysis and Dynamic Kernel Principal Component Analysis are used for fault diagnosis of Polyvinyl chloride (PVC polymerization process, while Fisher Discriminant Analysis (FDA method was adopted to make failure data for further separation. The simulation results show that the Dynamic Kernel Principal Component Analyses to fault diagnosis of Polyvinyl chloride (PVC polymerization process have better diagnostic accuracy, the Fisher Discriminant Analysis (FDA can further realize the fault isolation, and the actual fault in the process of Polyvinyl chloride (PVC polymerization production can be monitored by Dynamic Kernel Principal Component Analysis.

  12. Polyvinyl Chloride and Copolymers Production: National Emission Standards for Hazardous Air Pollutants (NESHAP) - 40 CFR 63 Subparts J & HHHHHHH

    Science.gov (United States)

    Learn about the regulations for the Polyvinyl Chloride and Copolymers Production Production regarding the emissions of hazardous air pollutants. Find Federal Register citations, read the rule, and find the rule history here.

  13. Localization of xanthine oxidoreductase activity using the tissue protectant polyvinyl alcohol and final electron acceptor Tetranitro BT

    NARCIS (Netherlands)

    Kooij, A.; Frederiks, W. M.; Gossrau, R.; van Noorden, C. J.

    1991-01-01

    We have detected xanthine oxidoreductase activity in unfixed cryostat sections of rat and chicken liver, rat duodenum, and bovine mammary gland using the tissue protectant polyvinyl alcohol, the electron carrier 1-methoxyphenazine methosulfate, the final electron acceptor Tetranitro BT, and

  14. Composites based on cellulose fiber nonwovens and a water-soluble polymer 2. Strength-deformation characteristics of the composites

    Science.gov (United States)

    Cerpakovska, D.; Kalnins, M.

    2012-09-01

    The relationship between the strength-deformation properties and certain structural characteristics (volume content of polymer and voids, orientation of fibers) of composites prepared by impregnation of cellulose fiber nonwovens (CFNs) with poly(vinyl alcohol) water solutions is discussed. With growth in the volume fraction of polymer to 0.25-0.30, the tensile elastic modulus and ultimate strength of the composites increase compared with those of CFN. As a consequence of enhanced adhesion among the cellulose fibers, the relative values of tensile strength and elastic modulus in the main orientation direction of the fibers is higher than in the perpendicular one. Therefore, with increasing content of polymer in the composite, its degree of anisotropy diminishes significantly. The punching strength almost linearly correlates with the tensile strength. The breaking strain in tension increases considerably with growing content of polymer, but the tearing strength changes only slightly.

  15. Rubber-like poly(vinyl alcohol) gel

    Energy Technology Data Exchange (ETDEWEB)

    Nambu, Masao (Nippon Oil Co. Ltd., Yokohama (Japan). Central Technical Research Lab.)

    1990-09-01

    Anomalous poly (vinyl alcohol) gel has been found in our laboratory since 1980. The gel is prepared by repeated freezing (or freeze-dehydration) of aqueous poly (vinyl alcohol). Experiments establish the fact that anomalous gel is never produced in the course of freezing, but during sustained thawing the gelation does occur. Moreover, it was found that the softening point of the gel increases at 37degC. It is assumed that crystal nuclei are generated on freezing, then on thawing, some of them grow to very fine crystals which act as polymer network-knots (cross-linking). Additional freezing provide other seeds, which grow similarly, and these are accumulated until rubber-like gel is produced. The gel was always water-resistant at 37degC, and the potassium permanganate consumption of the extracted water layer remained far below the official restricted value for medical materials. The gel can be sterilized with gamma-rays or chlorhexidine. Moreover, it satisfies the official standards of acute toxicity, pyrogen, intracutaneous reaction, hemolyzation, and intracorporeal implantation, respectively. Applications to adhesion-preventing membrane (for joint or pericardium), tamponade (for jaw defects), electrode (for electroretinogram or artificial inner ear), artificial denture base and phantoms for magnetic resonance imaging were examined. (author) 54 refs.

  16. The effect of amphiphilic polymers on the association, morphology and photophysical properties of hypocrellin coordination polymer/fullerene assemblies.

    Science.gov (United States)

    Ou, Zhize; Liu, Guixia; Gao, Yunyan; Li, Shayu; Li, Huizhen; Li, Yi; Wang, Xuesong; Yang, Guoqiang; Wang, Xin

    2014-11-01

    The yttrium coordination polymer of pyrene modified hypocrellin A (Y(3+)-PyrHA) is synthesized and characterized. The methoxydiglycol malonate modified fullerene can be included in the cavity of Y(3+)-PyrHA in organic solution and buffer solution containing amphiphilic polymers, such as polyvinyl pyrrolidone (PVP), pluronic F127 and P123. The interaction between an amphiphilic polymer and Y(3+)-PyrHA plays an important role in controlling the size and morphology of Y(3+)-PyrHA/fullerene. TEM images of Y(3+)-PyrHA/fullerene in 1% F127 and P123 show nanoparticles in the size range 10-60 nm, while TEM images of Y(3+)-PyrHA/fullerene in 1% PVP display large-scale aggregation. Singlet oxygen is generated by irradiation of the polymer solution of Y(3+)-PyrHA/fullerene in the presence of oxygen. The electron paramagnetic resonance (EPR) spin trapping and 9,10-dimethoxyanthracene-2-sulfonic acid sodium salt (MAS) photooxidation results suggest that in 1% P123 solution Y(3+)-PyrHA/fullerene exhibits a higher singlet oxygen quantum yield than Y(3+)-PyrHA and the corresponding fullerene.

  17. Effect of Polyvinyl alcohol on Burning Rate for Flexible PVC with Addition of Magnesium hydroxide and Aluminum tri-hydroxide

    OpenAIRE

    Zuhair Jabbar Abdul Ameer; Diyar Hussein Habbeb

    2017-01-01

    In this research study the effect each of Polyvinyl alcohol, magnesium hydroxide, Aluminum trihydroxide on Polyvinyl chloride combustion speed used in the manufacture of electrical cables. Several composite samples were manufactured using the twin screw extruder. Combustion speed measured by the specification (ASTM D 635-03) as been studying composite samples surfaces using scanning electron microscope technology. The results that the parent used three additives reduce the combustion speed an...

  18. Effect of Polyvinyl alcohol on Burning Rate for Flexible PVC with Addition of Magnesium hydroxide and Aluminum tri-hydroxide

    Directory of Open Access Journals (Sweden)

    Zuhair Jabbar Abdul Ameer

    2017-05-01

    Full Text Available In this research study the effect each of Polyvinyl alcohol, magnesium hydroxide, Aluminum trihydroxide on Polyvinyl chloride combustion speed used in the manufacture of electrical cables. Several composite samples were manufactured using the twin screw extruder. Combustion speed measured by the specification (ASTM D 635-03 as been studying composite samples surfaces using scanning electron microscope technology. The results that the parent used three additives reduce the combustion speed and turning the surface of fine to coarse

  19. 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.

  20. Excited cooper pairs

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Arrietea, M. G.; Solis, M. A.; De Llano, M. [Universidad Nacional Autonoma de Mexico, Mexico, D.F (Mexico)

    2001-02-01

    Excited cooper pairs formed in a many-fermion system are those with nonzero total center-of mass momentum (CMM). They are normally neglected in the standard Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity for being too few compared with zero CMM pairs. However, a Bose-Einstein condensation picture requires both zero and nonzero CMM pairs. Assuming a BCS model interaction between fermions we determine the populations for all CMM values of Cooper pairs by actually calculating the number of nonzero-CMM pairs relative to that of zero-CMM ones in both 2D and 3D. Although this ratio decreases rapidly with CMM, the number of Cooper pairs for any specific CMM less than the maximum (or breakup of the pair) momentum turns out to be typically larger than about 95% of those with zero-CMM at zero temperature T. Even at T {approx}100 K this fraction en 2D is still as large as about 70% for typical quasi-2D cuprate superconductor parameters. [Spanish] Los pares de cooper excitados formados en un sistema de muchos electrones, son aquellos con momentos de centro de masa (CMM) diferente de cero. Normalmente estos no son tomados en cuenta en la teoria estandar de la superconductividad de Bardeen-Cooper-Schrieffer (BCS) al suponer que su numero es muy pequeno comparados con los pares de centro de masa igual a cero. Sin embargo, un esquema de condensacion Bose-Einstein requiere de ambos pares, con CMM cero y diferente de cero. Asumiendo una interaccion modelo BCS entre los fermiones, determinamos la poblacion de pares cooper con cada uno de todos los posibles valores del CMM calculando el numero de pares con momentos de centro de masa diferente de cero relativo a los pares de CMM igual a cero, en 2D y 3D. Aunque esta razon decrece rapidamente con el CMM, el numero de pares de cooper para cualquier CMM especifico menor que el momento maximo (o rompimiento de par) es tipicamente mas grande que el 95% de aquellos con CMM cero. Aun a T {approx}100 K esta fraccion en 2D es

  1. 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

  2. Uniform excitations in magnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    Steen Mørup

    2010-11-01

    Full Text Available We present a short review of the magnetic excitations in nanoparticles below the superparamagnetic blocking temperature. In this temperature regime, the magnetic dynamics in nanoparticles is dominated by uniform excitations, and this leads to a linear temperature dependence of the magnetization and the magnetic hyperfine field, in contrast to the Bloch T3/2 law in bulk materials. The temperature dependence of the average magnetization is conveniently studied by Mössbauer spectroscopy. The energy of the uniform excitations of magnetic nanoparticles can be studied by inelastic neutron scattering.

  3. Uniform excitations in magnetic nanoparticles

    DEFF Research Database (Denmark)

    Mørup, Steen; Frandsen, Cathrine; Hansen, Mikkel Fougt

    2010-01-01

    We present a short review of the magnetic excitations in nanoparticles below the superparamagnetic blocking temperature. In this temperature regime, the magnetic dynamics in nanoparticles is dominated by uniform excitations, and this leads to a linear temperature dependence of the magnetization...... and the magnetic hyperfine field, in contrast to the Bloch T3/2 law in bulk materials. The temperature dependence of the average magnetization is conveniently studied by Mössbauer spectroscopy. The energy of the uniform excitations of magnetic nanoparticles can be studied by inelastic neutron scattering....

  4. The use of filter paper plasticized with polyvinyl alcohol-glutaraldehyde in ELISA

    Directory of Open Access Journals (Sweden)

    G.H.T.S. Barbosa

    2000-07-01

    Full Text Available F1-antigen purified from Yersinia pestis was covalently linked to 5-mm diameter filter paper discs plasticized with polyvinyl alcohol-glutaraldehyde. These discs were used both for ELISA and dot-ELISA for the detection of anti-F1 IgG in rabbits. The best conditions were achieved using 1.25 µg of F1 antigen/disc, 3% w/v skim milk in PBS as blocking agent, anti-IgG peroxidase conjugate diluted 12,000 times, and serum from rabbits immunized or not against Y. pestis, diluted 6,400 times. The absorbance values obtained from the comparative study between this procedure and conventional ELISA were not significantly different but the low cost of the reagents employed in ELISA using the filter paper discs plasticized with polyvinyl alcohol-glutaraldehyde makes this method economically attractive.

  5. Antimicrobial and water-triggered release characteristics of a copper sulfate-polyvinyl acetate adhesive composite

    Science.gov (United States)

    De Jesus, A. P. O.; Roxas-Villanueva, R. M. L.; Herrera, M. U.

    2017-05-01

    Water-triggered release of antimicrobial solutions is advantageous in inhibiting the growth of bacteria and fungi in moist and wet environments. In this study, we fabricated a composite, by mixing polyvinyl acetate adhesive with copper sulfate solution, which exhibits antimicrobial activities against bacteria. Polyvinyl acetate adhesive serves as the binder and water soluble substance while copper sulfate serves as the antimicrobial agent. The composite was coated in an acetate film and air-dried. To monitor the rate of release of copper ions, the composite was submerged in water and the conductivity was measured. The conductivity saturation time was determined. The composite showed antimicrobial activity against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive).

  6. Synthesis of poly(vinyl acetate-methyl methacrylate) copolymer microspheres using suspension polymerization.

    Science.gov (United States)

    Islam, Md Shahidul; Yeum, Jeong Hyun; Das, Ajoy Kumar

    2012-02-15

    Poly(vinyl acetate-methyl methacrylate) (VAc-MMA) copolymer microspheres were prepared using suspension polymerization at low temperature initiated with 2,2'-azobis(2,4-dimethyl valeronitrile) (ADMVN). The poly(VAc-MMA) copolymer microspheres can be used over a large area where homopolymers, polyvinyl acetate (PVAc) and methyl methacrylate (PMMA) microspheres are capable of being put to use. The prepared microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Obtained copolymer microspheres which have 200 μm average diameter and higher thermal stability than those of homopolymer. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

  7. A poly(vinyl alcohol)/sodium alginate blend monolith with nanoscale porous structure

    OpenAIRE

    Sun, Xiaoxia; Uyama, Hiroshi

    2013-01-01

    A stimuli-responsive poly(vinyl alcohol) (PVA)/sodium alginate (SA) blend monolith with nanoscale porous (mesoporous) structure is successfully fabricated by thermally impacted non-solvent induced phase separation (TINIPS) method. The PVA/SA blend monolith with different SA contents is conveniently fabricated in an aqueous methanol without any templates. The solvent suitable for the fabrication of the present blend monolith by TINIPS is different with that of the PVA monolith. The nanostructu...

  8. Polyvinyl alcohol/chitosan/montmorillonite nanocomposites preparation by freeze/thaw cycles and characterization

    Directory of Open Access Journals (Sweden)

    Părpăriţă Elena

    2014-12-01

    Full Text Available Polyvinyl alcohol (PVA and chitosan (CS based hydrogels are often chosen to obtain hydrogels as being considered non-toxic for human body. The present study aims the preparation and physical chemical characterisation of hydrogels based PVA and CS by using an environmental friendly method i.e. freeze/thaw. In this method the only parameters affecting the hydrogels’ properties is the PVA concentration in solution, time and number of cycles of freezing / thawing. Repeated freezing and thawing cycles resulted in production of a highly elastic polyvinyl alcohol hydrogel with higher degree of crystallization. Adding chitosan in polyvinyl alcohol hydrogel is giving to the newly formed material, biocompatibility and antibacterial properties due to the free amino groups of chitosan. Higher mechanical and thermal characteristics of PVA/CS based hydrogels were obtained by addition of a small amount of inorganic nanoparticles (montmorillonite clay, C30B into the matrix (i.e. 1%. Scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FT-IR, near-infrared chemical imaging spectroscopy (NI-CI, X-ray diffraction (XRD, thermogravimetric analysis (TG, swelling and rheological measurements were used to characterize the polyvinyl alcohol/chitosan/montmorillonite properties. The swelling degree increased with decreasing chitosan content in hydrogels and the variation is opposite in nanocomposites, decreasing after introducing the nanoclay. The swelling behaviour was influenced by the presence of the nanoparticles. The plasticizer effect of the nanoparticles was reflected by obtaining a more compact hydrogel network with higher mechanical and thermal properties. The proposed materials can be a promising alternative in biomedical applications

  9. Pathology of angiosarcoma of the liver among vinyl chloride-polyvinyl chloride workers.

    Science.gov (United States)

    Thomas, L B; Popper, H

    1975-01-31

    We described the histologic features of 13 hepatic angiosarcomas which developed in workers engaged in the polymerization of vinyl chloride to polyvinyl chloride. Although the histologic features varied considerably in different portions of the angiosarcoma in the same liver and in the angiosarcomas of the liver from different patients, many features were similar such as sinusoidal, papillary, and cavernous growth patterns coincident with the precursor lesions of proliferation and atypia of sinusoidal lining cells.

  10. Preparation and Biodegradation of Nanocellulose Reinforced Polyvinyl Alcohol Blend Films in Bioenvironmental Media

    OpenAIRE

    Nusaiba Islam; Sharmin Jahan Proma; Ashiqur Rahman; Ashok Kumar Chakraborty

    2017-01-01

    Solution casting method was used to prepare nanocellulose reinforced polyvinyl alcohol (PVOH) from Oil palm empty fruit bunches. Different environmental test were used to investigate the biodegradability of the composite in soil and compost as well as in water and acidic solution. The morphology of the composite was investigated by scanning electron microscopy. The composite film with nanocellulose and without nanocellulose were compared, nanocellulose modified PVOH film showed more highly de...

  11. Characterisation of polyvinyl alcohol hydrogels modified with chitosan for cardiovascular applications

    OpenAIRE

    Mathews, David T.

    2006-01-01

    The use of Polyvinyl Alcohol (PVA) hydrogels combined with chitosan as a vascular tissue substitute for in vitro vascular cell culture studies was investigated. Hydrogels possess many characteristics that can be controlled and adjusted during the fabrication processes, such as tissue-like elasticity, mechanical strength and permeability. In order to develop a material with appropriate inherent material properties that may be used to fabricate a bioartificial vessel with appropriate structural...

  12. Polyvinyl butyral films containing leuco-malachite green as low-dose dosimeters

    Science.gov (United States)

    Mai, Hoang Hoa; Solomon, H. M.; Taguchi, M.; Kojima, T.

    2008-04-01

    Thin films containing leuco-malachite green (LMG) dye in polyvinyl butyral (PVB) have been developed for dose measurements of a few hundreds Gy level. The film shows significant color change in the visible range, and the sensitivity of the film to absorbed dose was enhanced by addition of chloride-containing compounds, such as chloral hydrate or 2,2,2-trichloroethanol. The film is suitable as dosimeters for dose measurements, e.g. in food irradiation and environmental protection.

  13. Effect of Saponification Condition on the Morphology and Diameter of the Electrospun Poly(vinyl acetate Nanofibers for the Fabrication of Poly(vinyl alcohol Nanofiber Mats

    Directory of Open Access Journals (Sweden)

    Seong Baek Yang

    2016-10-01

    Full Text Available Novel poly(vinyl alcohol (PVA nanofiber mats were prepared for the first time through heterogeneous saponification of electrospun poly(vinyl acetate (PVAc nanofibers. The effect of varying the saponification conditions, including temperature, time, and concentration of the alkaline solution, on the morphology of the saponified PVA fibers were evaluated by field-emission scanning electron microscopy. At 25 °C, the saponified PVA fibers exhibited a broad diameter distribution. The average fiber diameter, however, was found to decrease with increasing saponification temperature. When the saponification time was increased from 6 to 30 h, the average fiber diameter decreased gradually from 1540 to 1060 nm. In addition, the fiber diameter and morphology were also affected by the concentration of the alkaline saponification solution. The most optimal conditions for fabrication of thin, uniform, and smooth PVA nanofibers corresponded to an alkaline solution containing 10 g each of NaOH, Na2SO4, and methanol per 100 g of water, a temperature of 25 °C, and a saponification time of 24 h.

  14. Tailor-made starch-based conjugates containing well-defined poly(vinyl acetate and its derivative poly(vinyl alcohol

    Directory of Open Access Journals (Sweden)

    2011-06-01

    Full Text Available Reversible addition-fragmentation chain transfer (RAFT polymerization was adopted to synthesize starch-based conjugates that possessed controllable architecture and properties. Starch-based xanthate agent was prepared and applied as chain transfer agent to conduct the living/controlled polymerization (LCP of vinyl acetate, which generated tailor-made conjugates of starch and well-defined poly(vinyl acetate (SVAc. The relevant derivatives, conjugates of starch and chain length-controlled poly(vinyl alcohol (SVA, were obtained subsequently. Various characterizations such as Fourier transform infrared spectra (FTIR, ultraviolet-visible spectroscopy (UV, proton nuclear magnetic resonance (1H NMR, gel permeation chromatography (GPC, X-ray diffraction (XRD, Thermogravimetric analysis (TGA, and dynamic mechanical thermal analysis (DMTA were performed to examine the structure of intermediates and the starch-based conjugates. Static contact angle measurements revealed that the hydrophilic character of starch-based conjugates was tunable. Well-defined SVAc was amphiphilic and it was able to self-assemble into size controllable micelles, which was verified by contact angles, transmission electron microscopy (TEM and dynamic light scattering (DLS tests. SVA exhibited much higher capability to form physically cross-linked hydrogel than starch did. Both the characteristic of SVAc and SVA were chain length-dependent.

  15. Electric conductivity of polymer films filled with magnetic nanoparticles

    Science.gov (United States)

    Rumyantsev, B. M.; Bibikov, S. B.; Bychkova, A. V.; Leontiev, V. G.; Berendyaev, V. I.; Sorokina, O. N.; Kovarskii, A. L.

    2016-12-01

    The conductivity of polymer composites with magnetic nanoparticles (MNP) containing magnetite and other MNP (Ni, Cu-Ni) in the layers and planar cells with Al electrodes is studied. For soluble polymers (polyvinylpyrrolidone and polyvinyl alcohol) containing 1-10 wt % of magnetite MNP, a substantial effect of MNP on surface conductivity is detected over a wide range (from 10-10 to 10-3 Ω-1). It is shown that the addition of magnetite MNP not only results in a considerable change in cell conductivity, but also leads to its partially irreversible variation (by an order of magnitude or more) via minor modifications of the experimental conditions (temperature, electric field). For high-resistance samples with low probabilities of conducting chain formation, temperature current peaks are observed upon moderate heating (up to 350 K). These peaks are similar to the maxima observed upon polymer electret thermodischarges when the charges are captured by the deep centers associated with separate MNP or MNP aggregates. The type and position of the maxima are determined by the characteristics of the polymer matrix. For polyvinylpyrrolidone composites, the maxima are observed some time after heating (the echo effect). With composites based on solventborne polymers (polyalkanesterimides, soluble polyimide) and Ni, Cu-Ni MNP, no change in film conductivity measured electrophotographically is observed, due to the formation of a dielectric coating formed by polymer macromolecules adsorbed on the MNP surface. An explanation based on the possible formation of magnetic aggregates of magnetite MNP and conducting chains is proposed. Magnetic aggregation IPM is proposed as one way of controlling cell conductivity.

  16. Indirect excitation of ultrafast demagnetization

    National Research Council Canada - National Science Library

    Vodungbo, B; Tudu, B; Perron, J; Delaunay, R; Müller, L; Berntsen, M.H; Grübel, G; Malinowski, G; Weier, C; Gautier, J; Lambert, G; Zeitoun, P; Gutt, C; Jal, E; Reid, A.H; Granitzka, P.W; Jaouen, N; Dakovski, G.L; Moeller, S; Minitti, M.P; Mitra, A; Carron, S; Pfau, B; von Korff Schmising, C; Schneider, M; Eisebitt, S; Lüning, J

    2016-01-01

    .... Upon excitation with an intense femtosecond-short IR laser pulse, the film exhibits the classical ultrafast demagnetization phenomenon although only a negligible number of IR photons penetrate the aluminum layer...

  17. Transport waves as crystal excitations

    Science.gov (United States)

    Cepellotti, Andrea; Marzari, Nicola

    2017-09-01

    We introduce the concept of transport waves by showing that the linearized Boltzmann transport equation admits excitations in the form of waves that have well-defined dispersion relations and decay times. Crucially, these waves do not represent single-particle excitations, but are collective excitations of the equilibrium distribution functions. We study in detail the case of thermal transport, where relaxons are found in the long-wavelength limit, and second sound is reinterpreted as the excitation of one or several temperature waves at finite frequencies. Graphene is studied numerically, finding decay times of the order of microseconds. The derivation, obtained by a spectral representation of the Boltzmann equation, holds in principle for any crystal or semiclassical transport theory and is particularly relevant when transport takes place in the hydrodynamic regime.

  18. Indirect excitation of ultrafast demagnetization

    OpenAIRE

    Boris Vodungbo; Bahrati Tudu; Jonathan Perron; Renaud Delaunay; Leonard Müller; Berntsen, Magnus H.; Gerhard Grübel; Grégory Malinowski; Christian Weier; Julien Gautier; Guillaume Lambert; Philippe Zeitoun; Christian Gutt; Emmanuelle Jal; Reid, Alexander H.

    2016-01-01

    Does the excitation of ultrafast magnetization require direct interaction between the photons of the optical pump pulse and the magnetic layer? Here, we demonstrate unambiguously that this is not the case. For this we have studied the magnetization dynamics of a ferromagnetic cobalt/palladium multilayer capped by an IR-opaque aluminum layer. Upon excitation with an intense femtosecond-short IR laser pulse, the film exhibits the classical ultrafast demagnetization phenomenon although only a ne...

  19. Stochastic Hierarchical Systems: Excitable Dynamics

    OpenAIRE

    Leonhardt, Helmar; Zaks, Michael A.; Falcke, Martin; Schimansky-Geier, Lutz

    2008-01-01

    We present a discrete model of stochastic excitability by a low-dimensional set of delayed integral equations governing the probability in the rest state, the excited state, and the refractory state. The process is a random walk with discrete states and nonexponential waiting time distributions, which lead to the incorporation of memory kernels in the integral equations. We extend the equations of a single unit to the system of equations for an ensemble of globally coupled oscillators, derive...

  20. Autowaves in moving excitable media

    Directory of Open Access Journals (Sweden)

    V.A.Davydov

    2004-01-01

    Full Text Available Within the framework of kinematic theory of autowaves we suggest a method for analytic description of stationary autowave structures appearing at the boundary between the moving and fixed excitable media. The front breakdown phenomenon is predicted for such structures. Autowave refraction and, particulary, one-side "total reflection" at the boundary is considered. The obtained analytical results are confirmed by computer simulations. Prospects of the proposed method for further studies of autowave dynamics in the moving excitable media are discussed.

  1. Have Gluonic Excitations Been Found?

    OpenAIRE

    Page, Philip R.

    1996-01-01

    New experimental information on the non-exotic J^PC = 0^-+ isovector seen at 1.8 GeV by VES yields convincing evidence of its excited gluonic (hybrid) nature when a critical study of alternative quarkonium assignments is made in the context of ^3 P_0 decay by flux-tube breaking. Production of this gluonic excitation via meson exchange is promising, although its two photon production vanishes.

  2. 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.

  3. Electron-excited molecule interactions

    Energy Technology Data Exchange (ETDEWEB)

    Christophorou, L.G. (Oak Ridge National Lab., TN (USA) Tennessee Univ., Knoxville, TN (USA). Dept. of Physics)

    1991-01-01

    In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10{sup 6} to 10{sup 7} times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs.

  4. Modifications induced in the polycarbonate Makrofol KG polymer by ...

    Indian Academy of Sciences (India)

    Swift heavy ions interact predominantly through inelastic scattering while traversing any polymer medium and produce excited/ionized atoms. Here samples of the polycarbonate Makrofol of approximate thickness 20 m, spin coated on GaAs substrate were irradiated with 50 MeV Li ion (+3 charge state). Build-in ...

  5. Acid membranes of poly(vinyl alcohol) for direct ethanol fuel cell applications; Membranes acidas de poli(alcool vinilico) para aplicacoes em celulas a combustivel via etanol direto

    Energy Technology Data Exchange (ETDEWEB)

    Dutra Filho, Jose C.; Gomes, Ailton S. [Instituto de Macromoleculas Professora Eloisa Mano, Universidade Federal do Rio de Janeiro, RJ (Brazil)], e-mail: asgomes@ima.ufrj.br

    2011-07-01

    Proton-conducting hybrid membranes composed of poly(vinyl alcohol) (PVA), phosphotungstic acid (HPW) and diethylenetriaminepentaacetic acid (DTPA) where prepared. The effect of HPW doping and crosslink with DTPA on the membranes properties such as uptake, pervaporation and proton conductivity was investigated. Uptake and permeated flux decreases with increasing content of HPW and DTPA. Ethanol permeabilities obtained was about two orders of magnitude smaller than Nafion 117. FTIR spectra indicated that HPW was incorporated into the polymer matrix and DTPA acted as crosslink agent. The proton conductivity was in the order of 10-3 S.cm-1 with added 4 wt.% of DTPA and generally increases with the addition of HPW. (author)

  6. Studies on the thermodynamics and solute–solvent interaction of Polyvinyl pyrrolidone wrapped single walled carbon nanotubes (PVP-SWNTs in water over temperature range 298.15–313.15 K

    Directory of Open Access Journals (Sweden)

    Malahah Mohamed

    2017-05-01

    Full Text Available The water solubilisation of single walled carbon nanotubes (SWNTs has been achieved by polymer wrapping. The present study aims at highlighting the solute–solvent interaction and thermodynamic parameters in the solubilisation of polyvinyl pyrrolidone wrapped single walled carbon nanotubes (PVP-SWNTs in water. Conductivity and density values of both PVP and PVP-SWNTs have been determined in water maintaining different concentrations (0.005–0.1 g/L at temperatures 298.15, 303.15, 308.15 and 313.15 K. The conductance values have been used to evaluate the limiting molar conductance (∧om and the activation energy (Es. From the density values, the limiting partial molar volumes and expansibilities have been calculated. The estimated parameters were discussed in terms of solute–solvent interactions.

  7. Fingerprinting polymer microarrays.

    Science.gov (United States)

    Tourniaire, Guilhem; Diaz-Mochon, Juan J; Bradley, Mark

    2009-08-01

    The incubation of "polymer microarrays" with labelled proteins and carbohydrates demonstrated polymer selective binding, giving an approach to cellular fingerprinting and offering a possible alternative to current arraying platforms for partitioning and analysis of complex cellular components.

  8. Mechanical Properties of Polymers.

    Science.gov (United States)

    Aklonis, J. J.

    1981-01-01

    Mechanical properties (stress-strain relationships) of polymers are reviewed, taking into account both time and temperature factors. Topics include modulus-temperature behavior of polymers, time dependence, time-temperature correspondence, and mechanical models. (JN)

  9. Antiviral Polymer Therapeutics

    DEFF Research Database (Denmark)

    Smith, Anton Allen Abbotsford

    2014-01-01

    polymerized in a controlled manner with carrier monomers of historically proven biocompatible polymers. The carrier polymers, the loading of ribavirin as well as the size of the polymer were varied systematically with the aid of an automated synthesis platform. These polymers were tested in a cellular assay...... of reversible-addition-fragmentation chain transfer polymerization, which not only controls the size of polymer, but also allows the introduction of a terminal amine on the polymer which can be used for further conjugation. This has allowed for not only fluorescent labeling of the polymer, but also protein......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...

  10. Anion exchange polymer electrolytes

    Science.gov (United States)

    Kim, Yu Seung; Kim, Dae Sik

    2015-06-02

    Anion exchange polymer electrolytes that include guanidinium functionalized polymers may be used as membranes and binders for electrocatalysts in preparation of anodes for electrochemical cells such as solid alkaline fuel cells.

  11. Bioinspired assembly of nanoplatelets for reinforced polymer nanocomposites

    Science.gov (United States)

    Huang, Wei-Han; Dou, Xuan; Jiang, Peng

    2011-04-01

    Bio-inspired assembly of platelet particles and polyelectrolytes into ordered layered nanocomposites, which mimic the brick-and-mortar nanostructure found in the nacreous layer of mollusk shells, is of great technological importance in developing light-weight reinforced materials, separation membranes, and gas-barrier coatings. Unfortunately, the widely utilized layer-by-layer self-assembly technology is tedious in creating thick multilayered coatings. Here we report a simple filtration technology that enables the scalable production of inorganic nanoplatelets-polymer nanocomposites with layered structures. Water suspended montmorillonite (MTM) nanoclay platelets are pre-mixed with polyvinyl alcohol (PVA) aqueous solution to make stable colloidal suspensions. By using a simple vacuum filtration setup, ordered layered MTM nanoclay-PVA nanocomposites with controlled thickness can be easily prepared. The resulting selfstanding films exhibit higher tensile strength and toughness than those of natural inorganic-organic nanocomposites including nacre, bone, and dentin.

  12. Study on characteristics of PVDF/nano-clay composite polymer electrolyte using PVP as pore-forming agent

    Energy Technology Data Exchange (ETDEWEB)

    Dyartanti, Endah R., E-mail: heru.susanto@undip.ac.id, E-mail: endah-rd@uns.ac.id [Departement of Chemical Engineering, Sebelas Maret University, Surakarta (Indonesia); Department of Chemical Engineering, Diponegoro University, Semarang (Indonesia); Purwanto, Agus [Departement of Chemical Engineering, Sebelas Maret University, Surakarta (Indonesia); Widiasa, I. Nyoman; Susanto, Heru, E-mail: heru.susanto@undip.ac.id, E-mail: endah-rd@uns.ac.id [Department of Chemical Engineering, Diponegoro University, Semarang (Indonesia)

    2016-02-08

    Polyvinylidene fluoride (PVDF) based polymer electrolytes have a high dielectric constant, which can assist in greater ionization of lithium salts. The main advantages of PVDF are its durability in long battery operation and its ability to be a good ion conductor. However, the limitation of this polymer is its crystalline molecular structure. Dispersing nano-particles in the polymer matrix may improve the characteristics of the PVDF polymer. This paper aims to investigate the impact of nano-clay addition on the characteristics of PVDF polymer to be used as a polymer electrolyte membrane. In addition, the effect of poly(vinyl pyrrolidone) (PVP) is also investigated. The membrane was prepared by phase separation method whereas the polymer electrolyte membranes was prepared by immersing into 1 M lithium hexafluorophosphate (LiPF{sub 6}) in ethylene carbonate/dimethyl carbonate (EC/DMC) electrolytes for 1 h. The membranes were characterized by scanning electron microscope (SEM), porosity and electrolyte uptake and performance in battery cell. The results showed that both nano-clay and PVP have significant impacts on the improvement of PVDF membranes to be used as polymer electrolyte.

  13. Polymer dynamics from synthetic polymers to proteins

    Indian Academy of Sciences (India)

    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.

  14. POLYMER CONCRETE CREEP

    OpenAIRE

    Yu. М. Borisov; I. S. Surovtsev; Yu. B. Potapov

    2012-01-01

    Problem statement. It is well known that creep is the tendency of a solid material to move slowly or deform permanently under the influence of stresses. The aim of the paper is to study the process of creep in polymer concretes. Results and conclusions. It is shown that creep in polymer concrete occurs according to the same pattern as in many other polymer composites with the elastic core. Equations which indirectly es-tablish the relation between complete deformations of polymer concrete, in...

  15. Modeling semiflexible polymer networks

    OpenAIRE

    Broedersz, Chase P.; MacKintosh, Fred C.

    2014-01-01

    Here, we provide an overview of theoretical approaches to semiflexible polymers and their networks. Such semiflexible polymers have large bending rigidities that can compete with the entropic tendency of a chain to crumple up into a random coil. Many studies on semiflexible polymers and their assemblies have been motivated by their importance in biology. Indeed, crosslinked networks of semiflexible polymers form a major structural component of tissue and living cells. Reconstituted networks o...

  16. Biopolymers Versus Synthetic Polymers

    OpenAIRE

    Florentina Adriana Cziple; António J. Velez Marques

    2008-01-01

    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...

  17. Sadomasochism, sexual excitement, and perversion.

    Science.gov (United States)

    Kernberg, O F

    1991-01-01

    Sadomasochism, an ingredient of infantile sexuality, is an essential part of normal sexual functioning and love relations, and of the very nature of sexual excitement. Sadomasochistic elements are also present in all sexual perversions. Sadomasochism starts out as the potential for erotic masochism in both sexes, and represents a very early capacity to link aggression with the libidinal elements of sexual excitement. Sexual excitement may be considered a basic affect that overcomes primitive splitting of love and hatred. Erotic desire is a more mature form of sexual excitement. Psychoanalytic exploration makes it possible to uncover the unconscious components of sexual excitement: wishes for symbiotic fusion and for aggressive penetration and intermingling; bisexual identifications; the desire to transgress oedipal prohibitions and the secretiveness of the primal scene, and to violate the boundaries of a teasing and withholding object. The relation between these wishes and the development of erotic idealization processes in both sexes is explored in the context of a critical review of the pertinent psychoanalytic literature.

  18. Coulomb excitation of (31)Mg

    CERN Document Server

    Seidlitz, M; Reiter, P; Bildstein, V; Blazhev, A; Bree, N; Bruyneel, B; Cederkall, J; Clement, E; Davinson, T; van Duppen, P; Ekstrom, A; Finke, F; Fraile, L M; Geibel, K; Gernhauser, R; Hess, H; Holler, A; Huyse, M; Ivanov, O; Jolie, J; Kalkuhler, M; Kotthaus, T; Krucken, R; Lutter, R; Piselli, E; Scheit, H; Stefanescu, I; van de Walle, J; Voulot, D; Warr, N; Wenander, F; Wiens, A

    2011-01-01

    The ground state properties of ^3^1Mg indicate a change of nuclear shape at N=19 with a deformed J^@p=1/2^+ intruder state as a ground state, implying that ^3^1Mg is part of the ''island of inversion''. The collective properties of excited states were the subject of a Coulomb excitation experiment at REX-ISOLDE, CERN, employing a radioactive ^3^1Mg beam. De-excitation @c-rays were detected by the MINIBALL @c-spectrometer in coincidence with scattered particles in a segmented Si-detector. The level scheme of ^3^1Mg was extended. Spin and parity assignment of the 945 keV state yielded 5/2^+ and its de-excitation is dominated by a strong collective M1 transition. Comparison of the transition probabilities of ^3^0^,^3^1^,^3^2Mg establishes that for th e N=19 magnesium isotope not only the ground state but also excited states are largely dominated by a deformed pf intruder configuration.

  19. Study of polymer film formation and their characterization using NMR, XRD and DSC

    Energy Technology Data Exchange (ETDEWEB)

    Ghoshal, Sushanta

    2012-07-01

    Film formation and their characterization of three eco-friendly polymers, namely gelatin, starch and poly(vinyl alcohol) (PVOH) were studied using nuclear magnetic resonance (NMR), wide-angle X-ray diffractometry (XRD) and differential scanning calorimetry (DSC) techniques. Polymer solutions were prepared using water as a solvent followed by casting. The drying process of the cast sample was monitored at room temperature with a single-sided NMR scanner until complete solidification occurred. Depth-dependent NMR profiles with microscopic resolution were acquired at different stages of sample drying. Each profile point was accumulated from the echo decay. Spin-spin relaxation times (T{sub 2}) were measured from the echo decays at different layers and were correlated with the drying process during film formation. Additionally, spin-lattice relaxation times (T{sub 1}) were determined. Depending on the polymer studied and the initial concentration of each polymer, different types of molecular dynamics were observed at different heights during evaporation of the solvent. The study indicates that each polymer shows a spatial heterogeneity in the molecular dynamics during drying. In the advanced stage of drying process, the microscopic arrangement of the polymer chains during their solidification is influenced by this dynamic heterogeneity and determines the final structure of the film. XRD of the film in its final state confirmed the structural heterogeneity identified by the NMR.

  20. Thermosetting Phthalocyanine Polymers

    Science.gov (United States)

    Fohlen, G.; Parker, J.; Achar, B.

    1985-01-01

    Group of phthalocyanine polymers resist thermal degradation. Polymers expected semiconducting. Principal applications probably in molded or laminated parts that have to withstand high temperatures. Polymers made from either of two classes of monomer: Bisphthalonitriles with imide linkages or Bisphthalonitriles with ester-imide linkages.