Radiation-induced cationic curing of vinyl ethers

International Nuclear Information System (INIS)

Lapin, S.C.

1992-01-01

Recently there has been an increasing interest in nonacrylate radiation-curable coatings. Vinyl ethers are particularly reactive under cationic polymerization reaction conditions. The high efficiency of the photoacid initiators combined with the high reactivity of vinyl ether monomers makes this a potentially very useful system. This chapter discusses the preparation of vinyl ethers, introduces vinyl ether-functional monomers and oligomers, describes radiation-induced cationic polymerization of vinyl ethers, and discusses various coating systems. Throughout the chapter, an emphasis is placed on radiation-curable coating applications. 64 refs., 5 figs., 11 tabs

Gamma radiolysis and vinyl esters

International Nuclear Information System (INIS)

De Bruyn, H.; Balic, R.; Gilbert, R.G.

1998-01-01

The principle behind γ relaxation of free-radical polymerizations is that the source of initiating radicals can be switched off 'instantaneously'. In the absence of initiating radicals the only kinetic events remaining are propagation, transfer and termination. For monomers whose propagation rate coefficients have been determined, relaxation behaviour can be interpreted to determine radical-loss rate coefficients and test models of loss mechanisms. This technique has been employed successfully on styrene and MMA emulsion polymerizations. In the present study, vinyl acetate and vinyl neo-decanoate (a ten-carbon-branched homologue of vinyl acetate) were studied, with the propagation rate coefficients for both monomers being established by pulsed-laser polymerization. Both were found to exhibit rapid γ relaxation rates in emulsion polymerization. This is a surprising result because mechanisms for rapid relaxation in emulsion polymerizations require that chain transfer to monomer (which is rapid for both monomers) is followed by exit from the particle into the aqueous phase with subsequent re-entry into a radical-containing particle leading to bimolecular termination. It is not unreasonable to suppose that this may be possible for vinyl acetate which is fairly water soluble (∼0.3 M). However, vinyl neo-decanoate is virtually insoluble (∼0.00004 M) and hence desorption is extremely unlikely. The most likely explanation for the observed rapid relaxations is that some of the radicals produced by γ radiolysis are slow to initiate vinyl esters and hence act as radical traps. As vinyl esters are known to be particularly unreactive monomers. it is feasible that this experimental artifact affects them to a much greater extent than some of the monomers studied successfully with this technique in the past

Preparation of Syndiotactic Poly(vinyl alcohol)/Poly(vinyl pivalate/vinyl acetate) Microspheres with Radiopacity Using Suspension Copolymerization and Saponification

Science.gov (United States)

Seok Lyoo, Won; Wook Cha, Jin; Young Kwak, Kun; Jae Lee, Young; Yong Jeon, Han; Sik Chung, Yong; Kyun Noh, Seok

2010-06-01

To prepare Poly(vinyl pivalate/vinyl acetate) [P(VPi/VAc)] microspheres with radiopacity, the suspension copolymerization approach in the presence of aqueous radiopaque nanoparticles was used. After, The P(VPi/VAc) microspheres with radiopacity were saponified in heterogeneous system, and then P(VPi/VAc) microspheres without aggregates were converted to s-PVA/P(VPi/VAc) microspheres of skin/core structure through the heterogeneous surface saponification. Radiopacity of microspheres was confirmed with Computed tomography (CT).

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 ...

The Effects of Reaction Variables on Solution Polymerization of Vinyl Acetate and Molecular Weight of Poly(vinyl alcohol Using Taguchi Experimental Design

Directory of Open Access Journals (Sweden)

M.H. Navarchian

2009-12-01

Full Text Available Poly(vinyl acetate is synthesized via solution polymerization, and then it is converted to poly(vinyl alcohol by alkaline alcoholysis. The aim of the work study was to investigate statistically the  influence of reaction variables in vinyl acetate polymerization, the conversion of this monomer to polymer, degree of branching of acetyl group in poly(vinyl acetate, as well as the molecular weight of poly(vinyl alcohol, using Taguchi experimental design approach. The reaction variables were polymerization time, molar ratio of initiator to monomer, and volume ratio of monomer to solvent. The statistical analysis of variance of the results revealed that all factors have significantly influenced the conversion and degree of branching. Volume ratio of monomer to solvent is the only factor affecting the molecular weight of poly(vinyl alcohol, and has the greatest influence on all responses. By increasing this ratio, the conversion, degree of branching of acetyl group in poly(vinyl acetate, and molecular weight of poly(vinyl alcohol were increased.

Preparation of poly (vinyl alcohol) membranes grafted with n-vinyl pyridine/ acrylic acid binary monomers

International Nuclear Information System (INIS)

Ajji, A.; Ali, A.

2014-03-01

Poly(vinyl alcohol) films were grafted with two monomers using gamma radiation, acrylic acid and N-vinyl pyridine. The influence of different parameters on the grafting yield was investigated as: the comonomer concentration and composition, and irradiation dose. The suitable conditions of the process had been determined to prepare PVA membranes have both properties of the two monomers, acrylic acid and vinyl pyridine as comonomer concentration and composition, and irradiation dose. Some properties of the membranes had been investigated as maximum swelling and grafting. Also the ability of the grafted films to adsorb some heavy metals and dyes was elaborated and discussed.(author)

Antimalarial effects of vinyl sulfone cysteine proteinase inhibitors.

OpenAIRE

Rosenthal, P J; Olson, J E; Lee, G K; Palmer, J T; Klaus, J L; Rasnick, D

1996-01-01

We evaluated the antimalarial effects of vinyl sulfone cysteine proteinase inhibitors. A number of vinyl sulfones strongly inhibited falcipain, a Plasmodium falciparum cysteine proteinase that is a critical hemoglobinase. In studies of cultured parasites, nanomolar concentrations of three vinyl sulfones inhibited parasite hemoglobin degradation, metabolic activity, and development. The antimalarial effects correlated with the inhibition of falcipain. Our results suggest that vinyl sulfones or...

Ambient gold-catalyzed O-vinylation of cyclic 1,3-diketone: A vinyl ether synthesis

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Yumeng Xi

2013-11-01

Full Text Available Gold-catalyzed O-vinylation of cyclic 1,3-diketones has been achieved for the first time, which provides direct access to various vinyl ethers. A catalytic amount of copper triflate was identified as the significant additive in promoting this transformation. Both aromatic and aliphatic alkynes are suitable substrates with good to excellent yields.

Synthesis of 2-vinylic indoles and derivatives via a Pd-catalyzed tandem coupling reaction.

Science.gov (United States)

Fayol, Aude; Fang, Yuan-Qing; Lautens, Mark

2006-09-14

A novel one-step synthesis of valuable 2-vinylic indoles and their tricycle derivatives is described. This reaction, which utilizes a gem-dibromovinyl unit as a readily available starting material, occurs via an efficient Pd-catalyzed tandem Buchwald-Hartwig/Heck reaction.

Copper-catalyzed oxidative Heck reactions between alkyltrifluoroborates and vinyl arenes.

Science.gov (United States)

Liwosz, Timothy W; Chemler, Sherry R

2013-06-21

We report herein that potassium alkyltrifluoroborates can be utilized in oxidative Heck-type reactions with vinyl arenes. The reaction is catalyzed by a Cu(OTf)2/1,10-phenanthroline with MnO2 as the stoichiometric oxidant. In addition to the alkyl Heck, amination, esterification, and dimerization reactions of alkyltrifluoroborates are demonstrated under analogous reaction conditions. Evidence for an alkyl radical intermediate is presented.

29 CFR 1910.1017 - Vinyl chloride.

Science.gov (United States)

2010-07-01

... employee exposure to vinyl chloride (chloroethene), Chemical Abstracts Service Registry No. 75014. (2) This section applies to the manufacture, reaction, packaging, repackaging, storage, handling or use of vinyl... this section by engineering, work practice, and personal protective controls as follows: (1) Feasible...

21 CFR 177.1350 - Ethylene-vinyl acetate copolymers.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-vinyl acetate copolymers. 177.1350 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1350 Ethylene-vinyl acetate copolymers. Ethylene-vinyl acetate copolymers may be safely used as articles or components of articles...

21 CFR 177.1950 - Vinyl chloride-ethylene copolymers.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Vinyl chloride-ethylene copolymers. 177.1950... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1950 Vinyl chloride-ethylene copolymers. The vinyl chloride-ethylene copolymers identified in paragraph (a) of this section may be safely...

Synthesis and characterisation of polymeric nanofibers poly (vinyl alcohol) and poly (vinyl alcohol)/silica using indigenous electrospinning set up

International Nuclear Information System (INIS)

Sasipriya, K.; Suriyaprabha, R.; Prabu, P.; Rajendran, V.

2013-01-01

Indigenous design and fabrication horizontal of electrospinning set up was developed to facilitate with double drum conveyor belt system to make ease in harvesting nanofibers rapidly. As a bench mark study, organic-inorganic nanofiber composite was synthesised employing our indigenous electrospinning set up. The aqueous solution of poly (vinyl alcohol) and poly (vinyl alcohol)/silica sol were employed to produce nanofiber mats in order to vary the experimental parameters such as voltage, solvent effect and the effect of catalyst. The synthesised pure electro spun poly (vinyl alcohol) and poly (vinyl alcohol)/silica sol fibers were characterized by Scanning electron microscopy (SEM), Atomic force microscopy (AFM) and Fourier transform infra red spectroscopy (FTIR). According to the results, the fine polymeric nanofibers were achieved in the size range of 100-500 nm for pure poly (vinyl alcohol) fiber and 100-700 nm for polyvinyl alcohol/silica and the constitution of silica in rendering better fiber mats with this double drum set up. (author)

Synthesis and characterisation of polymeric nanofibers poly (vinyl alcohol) and poly (vinyl alcohol)/silica using indigenous electrospinning set up

Energy Technology Data Exchange (ETDEWEB)

Sasipriya, K.; Suriyaprabha, R.; Prabu, P.; Rajendran, V., E-mail: veerajendran@gmail.com [Centre for Nanoscience and Technology, K. S. Rangasamy College of Technology, Tamil Nadu (India)

2013-11-01

Indigenous design and fabrication horizontal of electrospinning set up was developed to facilitate with double drum conveyor belt system to make ease in harvesting nanofibers rapidly. As a bench mark study, organic-inorganic nanofiber composite was synthesised employing our indigenous electrospinning set up. The aqueous solution of poly (vinyl alcohol) and poly (vinyl alcohol)/silica sol were employed to produce nanofiber mats in order to vary the experimental parameters such as voltage, solvent effect and the effect of catalyst. The synthesised pure electro spun poly (vinyl alcohol) and poly (vinyl alcohol)/silica sol fibers were characterized by Scanning electron microscopy (SEM), Atomic force microscopy (AFM) and Fourier transform infra red spectroscopy (FTIR). According to the results, the fine polymeric nanofibers were achieved in the size range of 100-500 nm for pure poly (vinyl alcohol) fiber and 100-700 nm for polyvinyl alcohol/silica and the constitution of silica in rendering better fiber mats with this double drum set up. (author)

Synthesis and characterisation of polymeric nanofibers poly (vinyl alcohol and poly (vinyl alcohol/silica using indigenous electrospinning set up

Directory of Open Access Journals (Sweden)

K. Sasipriya

2013-01-01

Full Text Available Indigenous design and fabrication horizontal of electrospinning set up was developed to facilitate with double drum conveyor belt system to make ease in harvesting nanofibers rapidly. As a bench mark study, organic-inorganic nanofiber composite was synthesised employing our indigenous electrospinning set up. The aqueous solution of poly (vinyl alcohol and poly (vinyl alcohol/silica sol were employed to produce nanofiber mats in order to vary the experimental parameters such as voltage, solvent effect and the effect of catalyst. The synthesised pure electro spun poly (vinyl alcohol and poly (vinyl alcohol/silica sol fibers were characterized by Scanning electron microscopy (SEM, Atomic force microscopy (AFM and Fourier transform infra red spectroscopy (FTIR. According to the results, the fine polymeric nanofibers were achieved in the size range of 100-500 nm for pure poly (vinyl alcohol fiber and 100-700 nm for polyvinyl alcohol/silica and the constitution of silica in rendering better fiber mats with this double drum set up.

Thermal stability of homo- and copolymers of vinyl fluoride

International Nuclear Information System (INIS)

Raucher, D.; Levy, M.

1979-01-01

The thermal stability of poly(vinyl fluoride)(PVF) was studied by thermal gravimetry and mass spectrometry (TGA and TGA-MS). In low-molecular-weight polymers a two-step decomposition pattern was observed. It consisted of the dehydrofluorination to a polyene chain followed by decomposition of the resulting polyene at higher temperatures. Copolymers of vinyl fluoride-vinyl acetate (VF-VAc) and vinyl fluoride-vinyl chloride (VF-VCl) showed a simultaneous evolution of hydrofluoric acid and acetic acid and hydrofluoric acid and hydrochloric acid, respectively. This suggests that after the elimination of the weakest link a spontaneous elimination of neighboring HF molecules takes place

29 CFR 1915.1017 - Vinyl chloride.

Science.gov (United States)

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Vinyl chloride. 1915.1017 Section 1915.1017 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1017 Vinyl chloride. Note: The requirements applicable to shipyard employment under this section...

Statistical analysis of nitrogen-containing vinyl copolymers: radiation-induced copolymerization of vinyl acetate and N-vinyl-2-pyrrolidone

International Nuclear Information System (INIS)

Peppas, N.A.; Gehr, T.W.B.

1979-01-01

Radiation-induced copolymerization of vinyl acetate and N-vinyl-2-pyrrolidone was carried out at 5 0 C using γ-irradiation of 1450 rads/min. Copolymers prepared at conversions lower than 5% were analyzed by a saponification technique. Various linear and nonlinear statistical analysis techniques were used to determine the reactivity ratios of this system as r 1 = 0.348 and r 2 = 3.108. These data were examined and analyzed in relation to problems of elemental analysis involving nitrogen-containing copolymers and to discrepancies in the reactivity ratios obtained by previous investigators. The presence of oxygen and a higher dose rate did not affect the copolymer composition within statistical error. Hydrolyzed copolymers prepared by this method have potential applications as biocompatible materials

Radiation fixation of vinyl chloride in an insecticide aerosol container

International Nuclear Information System (INIS)

Kagiya, V.T.; Takemoto, K.

1975-01-01

Recently, a large quantity of vinyl chloride has been used as spraying additive for insecticide aerosols. Since January 1974 when the Food and Drug Administration of the United States of America announced that vinyl chloride causes liver cancer, it has been forbidden in Japan and the United States of America to market insecticide aerosol containers containing vinyl chloride. In Japan, following a government order, about 20 million insecticide aerosol containers have been collected and put into storage. A report is given on the radiation fixation of vinyl chloride as polyvinylchloride powder by gamma-ray-induced polymerization in the aerosol container. Insecticide aerosol containers containing vinyl chloride were irradiated by gamma rays from 60 Co at room temperature. Vinyl chloride polymerized to form powdered polymer in the container. Polymerization conversion increased with the irradiation dose, and after 10 Mrad irradiation, vinyl chloride was not found in the sprayed gas. This establishes that vinyl chloride can be fixed by gamma-ray irradiation in the aerosol container. To accelerate the reaction rate, the effect of various additives on the reaction was investigated. It was found that halogenated hydrocarbons, such as chloroform and carbon tetrachloride, accelerated the initiation of the polymerization, and that a vinyl monomer such as vinyl acetate accelerated the reaction rate due to the promotion of the initiation and the high reactivity of the polyvinylacetate radical to vinyl chloride. Consequently, the required irradiation dose for the fixation of vinyl chloride was decreased to less than 5 Mrad by the addition of various kinds of additives. Following the request of the Ministry of Public Welfare, various technical problems for large-scale treatment are being studied with the co-operation of the Federation of Insecticide Aerosols. (author)

Radiation induced copolymerization of N-vinyl-2-pyrrolidone with vinyl acetate [Paper No. RD-3

International Nuclear Information System (INIS)

Ramakrishna, M.S.; Dhal, P.K.; Deshpande, D.D.; Babu, G.N.

1982-01-01

Copolymerization of N-vinyl-2-pyrrolidone (NVP) with vinyl acetate (VAC) was carried out using gamma-ray radiation. The compositions of the copolymers were determined from elemental analysis and the monomer reactivity ratios have been calculated using YBR method. The glass transition temperature and the intrinsic viscosities of the copolymers have been determined. All the experimental results were discussed in terms of the nature of the monomers. (author)

MILLIMETER WAVE SPECTRUM AND ASTRONOMICAL SEARCH FOR VINYL FORMATE

Energy Technology Data Exchange (ETDEWEB)

Alonso, E. R.; Kolesniková, L.; Cabezas, C.; Alonso, J. L. [Grupo de Espectroscopia Molecular (GEM), Edificio Quifima, Área de Química-Física, Laboratorios de Espectroscopia y Bioespectroscopia, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, E-47011 Valladolid (Spain); Tercero, B.; Cernicharo, J. [Grupo de Astrofísica Molecular, ICMM-CSIC, C/Sor Juana Inés de la Cruz 3, E-28049 Cantoblanco (Spain); Guillemin, J.-C. [Institut des Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, F-35708 Rennes Cedex 7 (France)

2016-11-20

Previous detections of methyl and ethyl formate make other small substituted formates potential candidates for observation in the interstellar medium. Among them, vinyl formate is one of the simplest unsaturated carboxylic ester. The aim of this work is to provide direct experimental frequencies of the ground vibrational state of vinyl formate in a large spectral range for astrophysical use. The room-temperature rotational spectrum of vinyl formate has been measured from 80 to 360 GHz and analyzed in terms of Watson’s semirigid rotor Hamiltonian. Two thousand six hundred transitions within J = 3–88 and K {sub a} = 0–28 were assigned to the most stable conformer of vinyl formate and a new set of spectroscopic constants was accurately determined. Spectral features of vinyl formate were then searched for in Orion KL, Sgr B2(N), B1-b, and TMC-1 molecular clouds. Upper limits to the column density of vinyl formate are provided.

Sorption of water vapor in partially hydrolyzed poly(vinyl acetate)

International Nuclear Information System (INIS)

Spencer, H.G.; Honeycutt, S.C.

1973-01-01

The sorption kinetics of H 2 O and D 2 O in copolymers of partially hydrolyzed poly(vinyl acetate) were studied and compared with the sorption kinetics of vinyl acetate--vinyl alcohol copolymers, and poly(vinyl alcohol). The special measurement problems presented by transient-state sorption studies in water vapor--polymer systems and their effects on the results are discussed

Vinyl acetate polymerization by ionizing radiation

International Nuclear Information System (INIS)

Mesquita, Andrea Cercan

2002-01-01

The aim of this work is the synthesis and characterization of the poly(vinyl acetate) using the ionizing radiation. Six polymerizations of vinyl acetate were carried out using three techniques of polymerization: in bulk, emulsion and solution. In the technique of solution polymerization were used two solvents, the alcohol ethyl and the methylethylketone, in two proportions 1:0.5 and 1:1 related to the monomer. The solutions were irradiated with gamma rays from a 60 Co source, with dose rate between 5.25 kGy/h and 6.26 kGy/h. The polymers obtained were characterized by Fourier Transform Infrared Spectroscopy (FTIR). The glass transition temperature (Tg) was investigated by Differential Scanning Calorimeter (DSC). The molecular weight was analyzed by the technique of Gel Permeation Chromatography (GPC). Tests of density, hardness and Vicat softening temperature were carried out. The infrared spectroscopy and others results confirmed that the polymers obtained by polymerization of vinyl acetate in bulk, emulsion and solution, using ionizing radiation, really correspond at poly(vinyl acetate). (author)

Hydrotelluration of alkynes: a unique route to Z-vinyl organometallics

Directory of Open Access Journals (Sweden)

Vieira Maurício L.

2001-01-01

Full Text Available The hydrotelluration reaction of alkynes is reviewed. The transformation of vinylic tellurides into reactive vinyl organometallics and the coupling reactions of vinylic tellurides with alkynes and organometallics are presented.

Copolymers of Vinyl-Containing Benzoxazine with Vinyl Monomers as Precursors for High Performance Thermosets

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Tsutomu Takeichi

2015-04-01

Full Text Available A benzoxazine containing a vinyl group (P-4va was prepared by the reaction of phenol, 4-vinylaniline, and paraformaldehyde. A differential scanning calorimetry (DSC study revealed that ring-opening polymerization of the benzoxazine and chain polymerization of the vinyl group occurred in the same temperature range. When 2,2'-azobisisobutyronitrile was added as a radical initiator to P-4va, however, only the vinyl groups were polymerized at lower temperature, giving oligo(P-4va that contains pendent benzoxazine units. Radical copolymerization of P-4va with various vinyl monomers such as styrene, methyl methacrylate (MMA, and n-butyl acrylate (BuA was examined. The chemical structure of the copolymers was confirmed by FT-IR and 1H-NMR to be one of polyolefins bearing benzoxazine units as the pendant groups. The weight-average molecular weights of the copolymers determined by size exclusion chromatography were to be in the range of 1900–51,500 depending on the comonomers. DSC of the copolymers showed that the maxima of the exothermic peaks corresponding to the ring-opening polymerization of the pendent benzoxazine units were observed in the temperature range of 229–250 °C. Thermal cure up to 240 °C of the copolymer films afforded homogenous transparent films with improved thermal properties. Tough cured film was obtained by the copolymerization with MMA, while a tough and flexible film was obtained by the copolymerization with BuA.

Williamson alkylation approach to the synthesis of poly(alkyl vinyl ether) copolymers

International Nuclear Information System (INIS)

Markova, D.; Christova, D.; Velichkova, R.

2008-01-01

A method for synthesis of poly(alkyl vinyl ether-co-vinyl alcohol) copolymers was developed based on the Williamson's alkylation of poly(vinyl acetate) (PVAc) with alkyl iodides. The influence of the alkylating agent and the reaction conditions on the efficiency of the modification reaction was investigated. The copolymers obtained were characterized by means of 1 H NMR and GPC. It was proved that by applying the proposed method copolymers of different composition and properties containing methyl vinyl ether, ethyl vinyl ether as well as n-butyl vinyl ether units could be prepared. Poly(methyl vinyl ether-co-vinyl alcohol)s of high degree of methylation exhibit sharp temperature response at 38-39 deg C in aqueous solution typical of the so-called smart polymers. (authors)

Tissue distribution of 1,2-14C-vinyl chloride in rats

International Nuclear Information System (INIS)

Buchter, A.; Bolt, H.M.; Kappus, H.; Bolt, W.

1977-01-01

Rats have been pretreatet with 6-nitro-1.2.3-benzothiadiazole which completely blocks the metabolism of vinyl chloride. If the animals are exposed to atmospheric vinyl chloride, the formation of an equilibrium between the compound in the gas phase and in the animal's organism is observed. Unmetabolized vinyl chloride is accumulated in the adipose tissue. The distribution pattern of vinyl in different organs of the rat is constant over the concentration range of 25-10,000 ppm of vinyl chloride in the exposure atmosphere. The distribution of metabolites of vinyl chloride contrasts to that of the original compound; metabolites primarily are concentrated in liver and in kidneys. (orig.) [de

Fracture inspection by BHTV logging through a vinyl chloride tube; Enbi pipe ga sonyusareta kosei deno BHTV ni yoru kiretsu chosa

Energy Technology Data Exchange (ETDEWEB)

Horikawa, H.; Okabe, T.; Takasugi, S. [GERD Geothermal Energy Research and Development Co. Ltd., Tokyo (Japan); Yamauchi, Y.; Imanishi, H. [Osaka Soil Test, Osaka (Japan)

1997-05-27

A borehole televiewer (BHTV) logging was conducted to investigate cracks in bored wells. The logging process shoots ultrasonic waves onto bore walls and utilizes reflection waves from the bore walls. If the bores are filled with muddy water, or the ultrasonic waves can pass through even if vinyl chloride tubes have been inserted after excavation, the state of the bore walls can be investigated in principle. Conventional optical scanners are, however, incapable of making this investigation. The BHTV logging can be used for identifying lithofacies from reflection intensities from bore walls (it depends on sound impedance of rocks), not to speak of finding cracks. As a result of making logging upon setting time windows from 105 to 145 {mu} sec in a bored well inserted with a vinyl chloride tube, cracks in the bore wall were identified clearly through the vinyl chloride tube. If the distance between the bore wall and the vinyl chloride tube becomes smaller, setting the time window becomes difficult, making reflection data acquisition more difficult. Impacts of decentering in the vinyl chloride tube on the data and the crack analysis result are small. The reflection intensity has decreased by about half as a result of having the circular vinyl chloride tube inserted. 5 refs., 9 figs., 1 tab.

Viscometric investigation of compatibilization of the poly(vinyl chloride)/poly(ethylene-co-vinyl acetate) blends by terpolymer of maleic anhydride styrene vinyl acetate

Science.gov (United States)

İmren, Dilek; Boztuğ, Ali; Yılmaz, Ersen; Zengin, H. Bayram

2008-11-01

In this study, a blend of poly(vinyl chloride) (PVC)/ethylene-co-vinyl acetate (EVA) was compatibilized by terpolymer of maleic anhydride-styrene-vinyl acetate (MAStVA) used as a compatibilizer. It was prepared the blends of 50/50 PVC/EVA containing 2-10% of the terpolymer. The compatibility experiences of these blends were investigated by using viscometric method in the range of concentrations (0.5-2.0 g dL -1) where tetrahydrofuran (THF) is the solvent. The interaction parameter (Δ b) was used to study the miscibility and compatibility of polymer blend in solution, obtained from the modified Krigbaum and Wall theory. Turbidity and FTIR measurements were also used to investigate the miscibility of this pair of polymers. The values of the relative viscosities of the each polymer solution and their blends were measured by a Cannon-Fenske type viscometer. In consequence of the study, it was observed that a considerable improvement was achieved in the miscibility of PVC/EVA blends by adding among 5 and 10 wt% of compatibilizer.

Radiation induced ionic polymerisation and grafting of vinyl monomers

International Nuclear Information System (INIS)

Stannett, V.T.

1981-01-01

Some special aspects of the radiation induced ionic polymerisation and grafting of vinyl monomers will be described. In particular the effects of solvents on the cationic polymerisation of the vinyl ethers will be discussed in detail. The unequivocal free ion nature of the polymerisation makes such information of considerable general interest. Estimates of the propagation rate constants with free cation polymerisation in solvents of different dielectric constants and solvation powers will be presented. Finally, some observations on the radiation induced graft polymerisation of ethyl vinyl ether to poly(vinyl chloride) and to polypropylene will be presented. (author)

Preparation of poly(vinyl alcohol) membranes grafted with N-vinyl imidazole/acrylic acid binary monomers

International Nuclear Information System (INIS)

Ajji, Zaki; Ali, Ali

2006-01-01

Poly(vinyl alcohol) films were grafted with two monomers using gamma radiation, acrylic acid and N-vinyl imidazole. The influence of different parameters on the grafting yield was investigated as: type of solvent and solvent composition, comonomer concentration and composition, addition of mineral acids, and irradiation dose. Water uptake in respect to the grafting yield was also evaluated. The ability of the grafted films to adsorb copper ions was elaborated and discussed for different grafting yields and ph values of the solution. (authors)

Direct Vinylation of Alcohols or Aldehydes Employing Alkynes as Vinyl Donors: A Ruthenium Catalyzed C-C Bond Forming Transfer Hydrogenation

Science.gov (United States)

Patman, Ryan L.; Chaulagain, Mani Raj; Williams, Vanessa M.; Krische, Michael J.

2011-01-01

Under the conditions of ruthenium catalyzed transfer hydrogenation, 2-butyne couples to benzylic and aliphatic alcohols 1a–1i to furnish allylic alcohols 2a–2i, constituting a direct C-H vinylation of alcohols employing alkynes as vinyl donors. Under related transfer hydrogenation conditions employing formic acid as terminal reductant, 2-butyne couples to aldehydes 4a, 4b, and 4e to furnish identical products of carbonyl vinylation 2a, 2b, and 2e. Thus, carbonyl vinylation is achieved from the alcohol or the aldehyde oxidation level in the absence of any stoichiometric metallic reagents. Nonsymmetric alkynes 6a–6c couple efficiently to aldehyde 4b to provide allylic alcohols 2m–2o as single regioisomers. Acetylenic aldehyde 7a engages in efficient intramolecular coupling to deliver cyclic allylic alcohol 8a. PMID:19173651

Swelling and mechanical properties of physically crosslinked poly(vinyl alcohol) hydrogels.

Science.gov (United States)

Suzuki, Atsushi; Sasaki, Saori

2015-12-01

Physically crosslinked poly(vinyl alcohol) gels are versatile biomaterials due to their excellent biocompatibility. In the past decades, physically crosslinked poly(vinyl alcohol) and poly(vinyl alcohol)-based hydrogels have been extensively studied for biomedical applications. However, these materials have not yet been implemented due to their mechanical strength. Physically crosslinked poly(vinyl alcohol) gels consist of a swollen amorphous network of poly(vinyl alcohol) physically crosslinked by microcrystallites. Although the mechanical properties can be improved to some extent by controlling the distribution of microcrystallites on the nano- and micro-scales, enhancing the mechanical properties while maintaining high water content remains very difficult. It may be technologically impossible to significantly improve the mechanical properties while keeping the gel's high water absorbance ability using conventional fabrication methods. Physical and chemical understandings of the swelling and mechanical properties of physically crosslinked poly(vinyl alcohol) gels are considered here; some promising strategies for their practical applications are presented. This review focuses more on the recent studies on swelling and mechanical properties of poly(vinyl alcohol) hydrogels, prepared using only poly(vinyl alcohol) and pure water with no other chemicals, as potential biomedical materials. © IMechE 2015.

Muonium-containing vinyl radicals

International Nuclear Information System (INIS)

Rhodes, C.J.; Symons, M.C.R.; Roduner, E.; Heming, M.

1987-01-01

Exposure of trimethylsilylacetylene and bis(trimethylsilyl)acetylene to positive muons gave radicals whose muon-electron hyperfine coupling constants establish that the corresponding vinyl radicals were formed. (author)

Mutagenicity of vinyl chloride after metabolic activation

Energy Technology Data Exchange (ETDEWEB)

Rannug, U; Johansson, A; Ramel, C; Wachtmeister, C A

1974-01-01

Vinyl chloride has recently been shown to cause a malignant liver tumor disease in man after occupational exposure in PVC plants. This actualizes the problem of whether such hazards could be avoided or at least diminished in the future by a screening for mutagenicity of chemicals used in industries. The basis for such a screening procedure is the close correlation between carcinogenic and mutagenic effects of chemicals. Experiments with Salmonella bacteria showed that the carcinogenic hazard of vinyl chloride could have been traced by means of mutagenicity tests. The data indicate that vinyl chloride is not mutagenic per se but becomes mutagenic after a metabolic activation in the liver. 24 references, 1 figure, 4 tables.

Direct 13C-1H coupling constants in the vinyl group of 1-vinylpyrazoles

International Nuclear Information System (INIS)

Afonin, A.V.; Voronov, V.K.; Es'kova, L.A.; Domnina, E.S.; Petrova, E.V.; Zasyad'ko, O.V.

1987-01-01

In a continuation of a study of the rotational isomerism of 1-vinylpyrazoles, they studied the direct 13 C- 1 H coupling constants in the vinyl group of 1-vinylpyrazole, 1-vinyl-4-bromopyrazole, 1-vinyl-3-methylpyrazole, 1-vinyl-5-methylpyrazole, 1-vinyl-3,5-dimethylpyrazole, and 1-vinyl-4-nitro-3,5-dimethylpyrazole. The 13 C- 1 H direct coupling constants in the vinyl group of 1-vinylpyrazoles are stereo-specific and vary with change in the conformer ratio

Hydrolysis of strained bridgehead bicyclic vinyl ethers and sulfides

International Nuclear Information System (INIS)

Chwang, W.K.; Kresge, A.J.; Wiseman, J.R.

1979-01-01

Rates of hydrolysis of the bridgehead bicyclic vinyl ether 9-oxabicyclo[3.3.1]non-1-ene(6) and its vinyl sulfide counterpart 9-thiabicyclo[3.3.1]non-1-ene(7), catalyzed by the hydronium ion, were measured in H 2 O and in D 2 O solution. These data give isotope effects, k/sub H//k/sub D/ = 2.4 and 1.9 respectively, which show that these reactions occur by the normal, rate-determining carbon protonation, mechanism. The vinyl ether 6 is less reactive than its olefin analogue, bicyclo[3.3.1]non-1-ene (relative rate 1:1/1400), as may have been expected for a constrained bicyclic system such as this, where stabilization of the bridgehead carbocation intermediate by conjugation with oxygen is severely impaired. The vinyl sulfide 7, however, is even less reactive than the vinyl ether (relative rates 1:1/140); this is a remarkable result in view of the fact that conjugation between the sulfur atom and the cationic center is presumably also strongly inhibited. 1 figure, 3 tables

Production of methyl-vinyl ketone from levulinic acid

Energy Technology Data Exchange (ETDEWEB)

Dumesic, James A [Verona, WI; West,; Ryan, M [Madison, WI

2011-06-14

A method for converting levulinic acid to methyl vinyl ketone is described. The method includes the steps of reacting an aqueous solution of levulinic acid, over an acid catalyst, at a temperature of from room temperature to about 1100 K. Methyl vinyl ketone is thereby formed.

Synthesis of Poly(vinyl ether) Thermoplastic Elastomers Having Functional Soft Segments

OpenAIRE

今枝, 嗣人; 漆崎, 美智遠; 阪口, 壽一; 橋本, 保; Tsuguto, IMAEDA; Michio, URUSHISAKI; Toshikazu, SAKAGUCHI; Tamotsu, HASHIMOTO

2013-01-01

The ABA-type triblock copolymers consisting of poly(2-adarnantyl vinyl ether) [poly(2-AdVE) as outer hard segments and poly(6-acetoxyhexyl vinyl ether) [poly(AcHVE)] poly(6-hydroxyhexyl vinyl ether) [poly(H HVE)], or poly(2-(2-methoxyethoxy)ethyl vinyl ether [poly(MOEOVE)] as inner soft segments were synthesized by sequential living cationic polymerization. Despite the presence of polar functional groups such as ester, hydroxy, and oxyethylene units in their soft segments, the two polymer seg...

Aerobic biodegradation of vinyl chloride in groundwater samples

International Nuclear Information System (INIS)

Davis, J.W.; Carpenter, C.L.

1990-01-01

Studies were conducted to examine the biodegradation of 14 C-labeled vinyl chloride in samples taken from a shallow aquifer. Under aerobic conditions, vinyl chloride was readily degraded, with greater than 99% of the labeled material being degraded after 108 days and approximately 65% being mineralized to 14 CO 2

Wearing ambidextrous vinyl gloves does not impair manual dexterity.

Science.gov (United States)

Drabek, Tomas; Boucek, Charles D; Buffington, Charles W

2013-01-01

Universal precautions mandate that health care workers wear gloves to prevent the unintended spread of bloodborne pathogens. Gloves may affect manual dexterity, generally delaying task completion. Our previous study showed that wearing the wrong size latex surgical glove degraded manual dexterity. The use of non-sterile and non-latex gloves may limit certain risks and be more cost-effective. However, such gloves may produce different results. We hypothesized that ambidextrous vinyl examination gloves would degrade manual dexterity compared with bare hands. We studied 20 random subjects from a medical environment. Subjects performed a standard battery of Grooved Pegboard tasks while bare-handed, wearing ambidextrous non-sterile vinyl gloves that were their preferred size, a size too small, and a size too large. The order was randomized with a Latin Square design to minimize the effects of time, boredom, and fatigue on the subjects. Subjects were also invited to comment on the fit of different size gloves. Wearing vinyl gloves of both the preferred size and a size up or down failed to affect manual dexterity vs. bare hands on time to insert pegs, and pegs dropped during insertion or removal. In contrast, the time to remove pegs was reduced by wearing preferred size vinyl gloves compared with performing the task with bare hands (Pgloves that were too small caused significant hand discomfort. Vinyl gloves surprisingly do not degrade manual dexterity even when worn in ill-fitting sizes. Wearing a preferred size vinyl glove vs. bare hands may improve dexterity in selected tasks. Choosing a comfortable, large size seems the best strategy when the preferred size is unavailable. Thinner vinyl gloves may improve grip and may not degrade touch as much as latex surgical gloves and may thus represent a reasonable choice for selected tasks.

IRIS Toxicological Review of Vinyl Chloride (Final Report, 2000)

Science.gov (United States)

EPA is announcing the release of the final report, Toxicological Review of Vinyl Chloride: in support of the Integrated Risk Information System (IRIS). The updated Summary for Vinyl Chloride and accompanying Quickview have also been added to the IRIS Database.

Graft copolymerization of styrene onto poly(vinyl alcohol) initiated by potassium diperiodatocuprate (III)

International Nuclear Information System (INIS)

Bai, L.; Wang, Ch.; Jin, J.; Liu, Y.

2009-01-01

The graft copolymerization of styrene onto poly(vinyl alcohol) is studied by using a novel redox system of potassium diperiodatocuprate-poly(vinyl alcohol) (Cu(III)poly(vinyl alcohol) in alkaline medium. Cu(III)-poly(vinyl alcohol) redox pair is an efficient initiator for this graft copolymerization which is proved by high graft efficiency (>97%) and high percentage of graft (>300%). Reaction conditions (monomer-to-poly(vinyl alcohol) weight ratio, initiator concentration, p H, time and temperature) affect the graft parameters which have been investigated systematically. The optimum reaction conditions are found as St/poly(vinyl alcohol) = 5.4; [Cu(III)] = 1*10 -2 M; p H = 12.7; temperature = 50 d eg C ; time = 3.5 h. Further, the equation of the overall polymerization rate can be written as follows: R p = k C 1.9 (St) C 1.7 (Cu(III)). The overall activation energy was calculated to be 42.0 kJ/mol based on the experimental data of the relations between R p and C(St); R p and C(Cu(III)); and R p and temperature. A mechanism is proposed to explain the formation of radicals and the initiation. The structure of the graft copolymers is confirmed by Fourier transfer infrared spectroscopy. Some peaks were compared with poly(vinyl alcohol) at 3080.34-3001.79 cm -1 (=C-H stretching in the phenyl ring), 1600.34-1450.95 cm -1 (C=C stretching in the phenyl ring), 755.17 cm -1 and 698.64 cm -1 (=C-H out-off-plane bending in phenyl ring) which are considered to belong to the characteristic absorption bands of phenyl group of polystyrene. Therefore it proves that the graft copolymer is composed of poly(vinyl alcohol) and polystyrene. thermal gravimetric analysis thermo grams of poly(vinyl alcohol) and poly(vinyl alcohol)-graft-polystyrene are investigated as well. As it is shown the initial decomposition temperature of poly(vinyl alcohol)-g-polystyrene(377.3 d eg C ) is much higher than that of poly(vinyl alcohol) (241.8 d eg C ), which indicates that the thermal stability of the

Syntheses of protoporphyrin-IX regioselectivity carbon-13 labelled at the alpha-vinyl carbons

International Nuclear Information System (INIS)

Smith, K.M.; Fujinari, E.M.

1986-01-01

A method for transformation of readily available beta-vinyl 99% carbon-13 enriched derivatives of protoporphyrin-IX dimethyl ester into the less accessible alpha-vinyl labelled isomers is described. The procedure involves thallium(III) promoted vinyl carbon rearrangement, and proceeds through 2,2-dimethoxyethyl, formylmethyl, 2-hydroxyethyl and 2-chloroethyl porphyrins; the rearranged vinyl groups are regenerated from 2-chloroethyl in the last step by treatment with base. No evidence of vinyl carbon scrambling in the sequence is observed, and spectroscopic data of the products are given. (author)

Effect of gamma ray on poly(lactic acid)/poly(vinyl acetate-co-vinyl alcohol) blends as biodegradable food packaging films

International Nuclear Information System (INIS)

Razavi, Seyed Mohammad; Dadbin, Susan; Frounchi, Masoud

2014-01-01

Poly(lactic acid) (PLA)/poly(vinyl acetate-co-vinyl alcohol) [P(VAc-co-VA)] blends as new transparent film packaging materials were prepared at various blend compositions and different vinyl alcohol contents. The blends and pure PLA were irradiated by gamma rays to investigate the extent of changes in the packaging material during gamma ray sterilization process. The miscibility of the blends was dependent on the blend composition and vinyl alcohol content; gamma irradiation had little effect on the extent of miscibility. The glass transition temperature of pure PLA and PLA/P(VAc-co-VA) miscible blends reduced after irradiation. On the other hand in PLA/P(VAc-co-VA) immiscible blends, while the glass transition temperature of the PLA phase decreased; that of the copolymer phase slightly increased. The reduction in the glass transition was about 10 percent for samples irradiated with 50 kGy indicating dominance of chain scission of PLA molecules at high irradiation dose. The latter was verified by drop in mechanical properties of pure PLA after exposing to gamma irradiation at 50 kGy. Blending of PLA with the copolymer P(VAc-co-VA) compensated greatly the adverse effects of irradiation on PLA. The oxygen-barrier property of the blend was superior to the neat PLA and remained almost intact with irradiation. The un-irradiated and irradiated blends had excellent transparency. Gamma ray doses used for sterilization purposes are usually less than 20 kGy. It was shown that gamma irradiation at 20 kGy had no or little adverse effects on PLA/P(VAc-co-VA) blends mechanical and gas barrier properties. - Highlights: • Poly(lactic acid)/poly(vinyl acetate-co-vinyl alcohol) blends were prepared as new packaging film. • The blends are superior to PLA in oxygen gas barrier property. • The blends are suitable for gamma ray sterilization and maintain useful mechanical properties. • The blends are perfectly transparent

In situ polymerization of vinyl monomers in polyester yarns

International Nuclear Information System (INIS)

Avny, Y.; Rebenfeld, L.; Weigmann, H.D.

1978-01-01

The effects of a pretreatment of polyester (PET) yarns with a strongly interacting solvent such as dimethylformamide (DMF) on vinyl monomer incorporation were investigated. When the DMF pretreatment is carried out at high temperatures (above 120 0 C), the swollen PET structure is stabilized by solvent-induced secondary crystallization. This substrate is highly suitable for the incorporation of vinyl monomers. In situ polymerization of vinyl monomers in DMF-treated PET was investigated using chemical and γ-irradiation polymerization techniques, both in the presence and in the absence of excess monomer outside the PET fibers. When polymerization was carried out in a system in which a constant supply of free radicals was available from the outside of the PET fibers, lower initiator concentrations and smaller γ-irradiation doses were necessary. These results are attributed to a low efficiency of the initiator inside the PET fiber due to mobility restrictions. Water uptake and moisture regain of PET yarns containing poly(hydroxyethyl methacrylate) and poly(acrylic acid) were also investigated. When most of the vinyl polymer was inside the PET fiber, water absorption was limited. The changes in mechanical properties of the PET yarns resulting from the DMF pretreatment were partially reversed by in situ polymerization of vinyl monomers

Research Needs: Glass Solar Reflectance and Vinyl Siding

Energy Technology Data Exchange (ETDEWEB)

Hart, Robert; Curcija, Charlie; Arasteh, Dariush; Goudey, Howdy; Kohler, Christian; Selkowitz, Stephen

2011-07-07

The subject of glass solar reflectance and its contribution to permanent vinyl siding distortion has not been extensively studied, and some phenomena are not yet well understood. This white paper presents what is known regarding the issue and identifies where more research is needed. Three primary topics are discussed: environmental factors that control the transfer of heat to and from the siding surface; vinyl siding properties that may affect heat build-up and permanent distortion; and factors that determine the properties of reflected solar radiation from glass surfaces, including insulating window glass. Further research is needed to fully characterize the conditions associated with siding distortion, the scope of the problem, physical properties of vinyl siding, insulating window glass reflection characteristics, and possible mitigation or prevention strategies.

Convenient procedures for the α-metallation of vinylic ethers and thioethers

NARCIS (Netherlands)

Verkruijsse, H.D.; Brandsma, L.; Schleyer, P. von R.

1987-01-01

Ethyl vinyl ether H2C=CHOC2H5 and the analogous cyclic vinylic ethers dehydrofuran and 2,3-dihydropyran can be potassiated at −20°C in the α-position with a 1/1/1 molar mixture of BuLi, t-BuOK and TMEDA in hexane. Methyl vinyl sulfide is potassiated very smoothly by a 1/1 molar mixture of BuLi and

Radiation-chemical preparation of poly(vinyl alcohol) hydrogels

International Nuclear Information System (INIS)

Duflot, Anastasia V.; Kitaeva, Natalia K.; Duflot, Vladimir R.

2015-01-01

This work reports the usage of method of radiation-chemical synthesis to prepare cross-linked hydrogels from poly(vinyl alcohol) modified with glycidyl methacrylate. Synthesis kinetics of modified poly(vinyl alcohol) and properties of hydrogels were studied. The gel fraction, swelling, mechanical properties, and water content of the hydrogels were measured. It was found that gel fraction increases with increasing radiation dose, concentration of modified poly(vinyl alcohol), and reaches 60%. It was established by differential scanning calorimetry that a fraction of the “bound” water in hydrogels is 50–70% and independent of gel fraction content. In addition to “bound” and “free” states, water in hydrogels is also present in the intermediate state. - Highlights: • The synthesis and the properties of poly(vinyl alcohol) hydrogels were studied. • PVA was modified by glycidyl methacrylate before gamma cross-linking. • The modification results in decreasing of PVA cross-linking dose by 3 orders lower. • The gel fraction and water content of the hydrogels were measured. • A fraction of the “bound” water in hydrogels is independent of gel fraction content

Mass spectrometric investigation of vinyl-substituted organic boron compounds

International Nuclear Information System (INIS)

Tarielashvili, V.O.; Ordzhonikidze, K.G.; Parulava, L.P.; Vakhaniya, G.V.

1992-01-01

Mass spectrometric investigation of vinyl-substituted organic compounds was conducted. Ionization was performed by electron shock. Possibility of determining boron isotope content is all analyzed organic boron vinyl-substituted compounds by direct method is shown. This simplifies sufficiently and lowers the price of analysis, improves its accuracy and rapidity

Thermogravimetric analysis of the polymer acrylate-vinyl ether mixture cured by radiation

International Nuclear Information System (INIS)

Danu, Sugiarto

1998-01-01

An experiment on thermal stability of the polymer acrylate-vinyl ether mixture cured by radiation have been done using thermogravimetric analysis. Three kinds of acrylic oligomers i.e., epoxy acrylate, urethane acrylate, and polypropylene glycol diacrylate, and vinyl ether monomers i.e., triethylene glycol divinyl ether (DVE-3), 1,4-cyclohexane dimethanol divinyl ether (CHVE), and butanediol monovinyl ether (HBVE) were used in the experiment. Reaction was taken via radical and cationic polymerisation. In case of cationic polymerisation, diphenyliodonium hexafluorophosphate fotoinisiator was used in the formulation. Thermogravimetric analysis was conducted in a nitrogen atmosphere at a flow rate of 40 ml/minute with a constant heating rate 10 o C and evaluation range were done from 25 to 500 o C. The results of thermogravimetric analysis showed that acrylate and DVE-3 mixture produced the polymer films with higher thermal stability than the mixture of acrylate with CHVE or HBVE. The composition of acrylate-vinyl ether mixture and degree of unsaturation of vinyl ether monomers influenced the thermal stability of polymer. The mixture of epoxy acrylate-vinyl ether and polypropylene glycol diacrylate-vinyl ether have 1 initial decomposition temperature whereas the urethane acrylate-vinyl ether mixture has 2 initial decomposition temperatures. (authors)

Oil recovery with sulfomethylated poly (lower alkyl vinyl ether/maleic anhydride)

Energy Technology Data Exchange (ETDEWEB)

Norton, C.J.; Falk, D.O.

1973-05-22

Lower alkyl vinyl ether e.g., methyl vinyl ether, propyl vinyl ether, isopropyl vinyl ether, hexyl vinyl ether, is copolymerized conventionally with maleic anhydride, the resulting copolymer is treated with ammonia or ammonium hydroxide to form the partial amide-ammonium salt, and this salt is in turn treated with formaldehyde and thereafter or simultaneously with ammonium or alkali metal salt sulfite (including bisulfites, etc.) to form an at least partially sulfomethylated copolymer. Aqueous solutions of the sulfomethylated copolymer are useful in increasing the viscosity of drive fluids used in the supplemented recovery of petroleum from subterranean formations. In general, enhancing the polyionic character of mobility control agents used in supplemented recovery of petroleum provides enhanced recovery. Achieving this enhancement of polyionic character through use of sulfonate groups provides a mobility control agent with good ability to sustain viscosity in the presence of brine and lime, usually present in the connate waters of petroleum-bearing formations. (7 claims)

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.

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.

Interpolymer complexses of vinyl ether copolymer with polyacrylic and polymethacrylic acids

Directory of Open Access Journals (Sweden)

E. Shaikhutdinov

2012-03-01

Full Text Available The interactions between macromolecules of copolymers based on vinyl ethers (vinyl ether of monoethanolamine and vinyl buthyl ether and 2-acryloilamido-2-methylpropanesulphonic acid with polyacrylic and polymethacrylic acid and, as well as study the effect of interpolymer interactions in the adsorption of polymers at the aqueous solution-air interface were investigated. The observed synergistic increase in surface activity of macromolecules into polyelectrolyte mixtures explained by the formation of interpolymer complexes polyacid - copolymer.

46 CFR 154.1750 - Butadiene or vinyl chloride: Refrigeration system.

Science.gov (United States)

2010-10-01

... and Operating Requirements § 154.1750 Butadiene or vinyl chloride: Refrigeration system. A... 46 Shipping 5 2010-10-01 2010-10-01 false Butadiene or vinyl chloride: Refrigeration system. 154.1750 Section 154.1750 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK...

Resonance Raman assignment and evidence for noncoupling of individual 2- and 4-vinyl vibrational modes in a monomeric cyanomethemoglobin

International Nuclear Information System (INIS)

Gersonde, K.; Yu, N.T.; Lin, S.H.; Smith, K.M.; Parish, D.W.

1989-01-01

We have investigated the resonance Raman spectra of monomeric insect cyanomethemoglobins (CTT III and CTT IV) reconstituted with (1) protohemes IX selectively deuterated at the 4-vinyl as well as the 2,4-divinyls, (2) monovinyl-truncated hemes such as pemptoheme (2-hydrogen, 4-vinyl) and isopemptoheme (2-vinyl, 4-hydrogen), (3) symmetric hemes such as protoheme III (with 2- and 3-vinyls) and protoheme XIII (with 1- and 4-vinyls), and (4) hemes without 2- and 4-vinyls such as mesoheme IX, deuteroheme IX, 2,4-dimethyldeuteroheme IX, and 2,4-dibromodeuteroheme IX. Evidence is presented that the highly localized vinyl C = C stretching vibrations at the 2- and 4-positions of the heme in these cyanomet CTT hemoglobins are noncoupled and inequivalent; i.e., the 1631- and 1624-cm-1 lines have been assigned to 2-vinyl and 4-vinyl, respectively. The elimination of the 2-vinyl (in pemptoheme) or the 4-vinyl (in isopemptoheme) does not affect the C = C stretching frequency of the remaining vinyl. Furthermore, two low-frequency vinyl bending modes at 412 and 591 cm-1 exhibit greatly different resonance Raman intensities between 2-vinyl and 4-vinyl. The observed intensity at 412 cm-1 is primarily derived from 4-vinyl, whereas the 591-cm-1 line results exclusively from the 2-vinyl. Again, there is no significant coupling between 2-vinyl and 4-vinyl for these two bending modes

1-O-vinyl glycosides via Tebbe olefination, their use as chiral auxiliaries and monomers.

Science.gov (United States)

Yuan, Jialong; Lindner, Kristof; Frauenrath, Holger

2006-07-21

A series of anomerically pure 1-O-formyl glycosides 1 was prepared and converted into the corresponding 1-O-vinyl glycosides 2 by Tebbe olefination. The unsubstituted vinyl glycosides were obtained as anomerically pure compounds in good yields, and the method of preparation was compatible with the presence of a variety of functional groups. Remarkably, the anomeric formate group was regioselectively converted into the corresponding olefin in the presence of acetate and benzoate protecting groups. With the perspective to use the 1-O-vinyl glycosides as monomers for the preparation of glycosylated poly(vinyl alcohol) derivatives with controlled tacticity, their scope as chiral auxiliaries for a stereodifferentiation in addition reactions to the olefin function was investigated by using the [2+2] cycloaddition to dichloroketene as a model reaction. In particular, vinyl 2,3,4,6-tetra-O-benzoyl-alpha-d-mannopyranoside (2i) exhibited excellent diastereoselectivity. Finally, the 1-O-vinyl glycosides were successfully subjected to radical homopolymerization in bulk or used as electron-rich comonomers in radical copolymerizations with maleic anhydride, yielding alternating, glycosylated poly(vinyl alcohol-alt-maleic anhydride).

Poly(vinyl acetate)/clay nanocomposite materials for organic thin film transistor application.

Science.gov (United States)

Park, B J; Sung, J H; Park, J H; Choi, J S; Choi, H J

2008-05-01

Nanocomposite materials of poly(vinyl acetate) (PVAc) and organoclay were fabricated, in order to be utilized as dielectric materials of the organic thin film transistor (OTFT). Spin coating condition of the nanocomposite solution was examined considering shear viscosity of the composite materials dissolved in chloroform. Intercalated structure of the PVAc/clay nanocomposites was characterized using both wide-angle X-ray diffraction and TEM. Fracture morphology of the composite film on silicon wafer was also observed by SEM. Dielectric constant (4.15) of the nanocomposite materials shows that the PVAc/clay nanocomposites are applicable for the gate dielectric materials.

The Effect of Salt on the Complex Coacervation of Vinyl Polyelectrolytes

Directory of Open Access Journals (Sweden)

Sarah L. Perry

2014-06-01

Full Text Available Complex coacervation is an electrostatically-driven phase separation phenomenon that is utilized in a wide range of everyday applications and is of great interest for the creation of self-assembled materials. Here, we utilized turbidity to characterize the effect of salt type on coacervate formation using two vinyl polyelectrolytes, poly(acrylic acid sodium salt (pAA and poly(allylamine hydrochloride (pAH, as simple models for industrial and biological coacervates. We confirmed the dominant role of salt valence on the extent of coacervate formation, while demonstrating the presence of significant secondary effects, which can be described by Hofmeister-like behavior. These results revealed the importance of ion-specific interactions, which are crucial for the informed design of coacervate-based materials for use in complex ionic environments, and can enable more detailed theoretical investigations on the role of subtle electrostatic and thermodynamic effects in complex coacervation.

The Effect of Salt on the Complex Coacervation of Vinyl Polyelectrolytes

Energy Technology Data Exchange (ETDEWEB)

Perry, Sarah; Li, Yue; Priftis, Dimitrios; Leon, Lorraine; Tirrell, Matthew

2014-06-01

Complex coacervation is an electrostatically-driven phase separation phenomenon that is utilized in a wide range of everyday applications and is of great interest for the creation of self-assembled materials. Here, we utilized turbidity to characterize the effect of salt type on coacervate formation using two vinyl polyelectrolytes, poly(acrylic acid sodium salt) (pAA) and poly(allylamine hydrochloride) (pAH), as simple models for industrial and biological coacervates. We confirmed the dominant role of salt valence on the extent of coacervate formation, while demonstrating the presence of significant secondary effects, which can be described by Hofmeister-like behavior. These results revealed the importance of ion-specific interactions, which are crucial for the informed design of coacervate-based materials for use in complex ionic environments, and can enable more detailed theoretical investigations on the role of subtle electrostatic and thermodynamic effects in complex coacervation.

Radicals derived from acetaldehyde and vinyl alcohol.

Science.gov (United States)

Estep, Marissa L; Morgan, W James; Winkles, Alexander T; Abbott, Adam S; Villegas-Escobar, Nery; Mullinax, J Wayne; Turner, Walter E; Wang, Xiao; Turney, Justin M; Schaefer, Henry F

2017-10-18

Vinyl alcohol and acetaldehyde are isoelectronic products of incomplete butanol combustion. Along with the radicals resulting from the removal of atomic hydrogen or the hydroxyl radical, these species are studied here using ab initio methods as complete as coupled cluster theory with single, double, triple, and perturbative quadruple excitations [CCSDT(Q)], with basis sets as large as cc-pV5Z. The relative energies provided herein are further refined by including corrections for relativistic effects, the frozen core approximation, and the Born-Oppenheimer approximation. The effects of anharmonic zero-point vibrational energies are also treated. The syn conformer of vinyl alcohol is predicted to be lower in energy than the anti conformer by 1.1 kcal mol -1 . The alcoholic hydrogen of syn-vinyl alcohol is found to be the easiest to remove, requiring 84.4 kcal mol -1 . Five other radicals are also carefully considered, with four conformers investigated for the 1-hydroxyvinyl radical. Beyond energetics, we have conducted an overhaul of the spectroscopic literature for these species. Our results also provide predictions for fundamental modes yet to be reported experimentally. To our knowledge, the ν 3 (3076 cm -1 ) and ν 4 (2999 cm -1 ) C-H stretches for syn-vinyl alcohol and all but one of the vibrational modes for anti-vinyl alcohol (ν 1 -ν 14 ) are yet to be observed experimentally. For the acetyl radical, ν 6 (1035 cm -1 ), ν 11 (944 cm -1 ), ν 12 (97 cm -1 ), and accounting for our changes to the assignment of the 1419.9 cm -1 experimental mode, ν 10 (1441 cm -1 ), are yet to be observed. We have predicted these unobserved fundamentals and reassigned the experimental 1419.9 cm -1 frequency in the acetyl radical to ν 4 rather than to ν 10 . Our work also strongly supports reassignment of the ν 10 and ν 11 fundamentals of the vinoxy radical. We suggest that the bands assigned to the overtones of these fundamentals were in fact combination bands. Our

Radiation-induced emulsion copolymerization of vinyl chloride with vinyl acetate in an engineering flow system

International Nuclear Information System (INIS)

Tsai, J.T.; Stahel, E.P.; Stannett, V.T.

1979-01-01

A flow reactor system was used to study the radiation-induced emulsion copolymerization of vinyl chloride with vinyl acetate. The emulsion was recirculated from a stirred vessel through transfer lines to a tubular reactor located within a high-intensity Co-60 source. The effects of physical chemical variables such as soap concentration, phase ratio, reaction temperature and residence time distribution on the molecular weight properties were investigated. The rate of copolymerization was found to be proportional to the 0.17 power of the soap concentration. Variation of the monomer-water ratio produced no significant change in rate. The rate increased with an increase in temperature over the range 5 to 50 0 C, while the average molecular weights of the copolymer increased with decreasing polymerization temperature. The molecular weight distribution in this engineering system was found to be essentially similar to those produced in a batch system

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... AIR POLLUTANTS National Emission Standard for Vinyl Chloride § 61.65 Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants. An owner or operator of an ethylene dichloride...

Preparation and characterization of film of poly vinyl acetate ethylene copolymer emulsion

International Nuclear Information System (INIS)

Zhang, Yanhua; Gu, Jiyou; Tan, Haiyan; Shi, Junyou; Di, Mingwei; Zuo, Yingfeng; Qiu, Si

2013-01-01

In order to improve the storage modulus and water resistance of poly (vinyl acetate), the vinyl acetate and poly (vinyl alcohol) (PVA) were respectively used as monomers and protective colloid to prepare a new kind of polyvinyl acetate emulsion adhesive by continuous emulsion polymerization. The dynamic mechanics, particle distribution, glass transition temperature, polymer emulsion structure of both polymerized and copolymerized emulsion were analyzed by SEM, DMA and XPS, respectively. The results indicated that the copolymerized emulsion has the appropriate particle size and the uniform particle distribution, the glass transition temperature increased from 50 °C to 70 °C, compared with poly (vinyl acetate). It could be seen from XPS spectra of copolymerized emulsion that key characteristic peak of C=O was still existent. X-ray photoelectron spectra revealed that the addition of EVA did not generate the new bond, whereas the maximum percentage increases in ester was determined in the composite film with the introduction of EVA of 25%, which indicated that the composite film has copolymer structure. The storage modulus and water resistance of poly (vinyl acetate) were improved due to the introduction of the EVA.

Radiation curing of mixtures of diallylphthalate prepolymer and vinyl monomer, 9

International Nuclear Information System (INIS)

Gotoda, Masao; Kitada, Yoshinori.

1975-01-01

Radiation curing, mainly by electron beams was studied with mixtures of low molecular weight diallylphthalate prepolymer (DAPsub(p).L) and vinyl monomers with special reference to their workability. Among the vinyl monomers, acrylonitrile gave a solution of low viscosity and methyl acrylate gave a solution of low dose curing. Radiation curing of DAPsub(p).L/vinyl monomer mixtures impregnated in wood was also tried. To obtain uniform wood-polymer composites, γ-irradiation after impregnation at 10 kg/cm 2 was found to be required for thick plate (110 mm), while electron beam irradiation after impregnation at normal pressure was sufficient for thin plate. (author)

Effect of gamma ray on poly(lactic acid)/poly(vinyl acetate-co-vinyl alcohol) blends as biodegradable food packaging films

Science.gov (United States)

Razavi, Seyed Mohammad; Dadbin, Susan; Frounchi, Masoud

2014-03-01

Poly(lactic acid) (PLA)/poly(vinyl acetate-co-vinyl alcohol) [P(VAc-co-VA)] blends as new transparent film packaging materials were prepared at various blend compositions and different vinyl alcohol contents. The blends and pure PLA were irradiated by gamma rays to investigate the extent of changes in the packaging material during gamma ray sterilization process. The miscibility of the blends was dependent on the blend composition and vinyl alcohol content; gamma irradiation had little effect on the extent of miscibility. The glass transition temperature of pure PLA and PLA/P(VAc-co-VA) miscible blends reduced after irradiation. On the other hand in PLA/P(VAc-co-VA) immiscible blends, while the glass transition temperature of the PLA phase decreased; that of the copolymer phase slightly increased. The reduction in the glass transition was about 10 percent for samples irradiated with 50 kGy indicating dominance of chain scission of PLA molecules at high irradiation dose. The latter was verified by drop in mechanical properties of pure PLA after exposing to gamma irradiation at 50 kGy. Blending of PLA with the copolymer P(VAc-co-VA) compensated greatly the adverse effects of irradiation on PLA. The oxygen-barrier property of the blend was superior to the neat PLA and remained almost intact with irradiation. The un-irradiated and irradiated blends had excellent transparency. Gamma ray doses used for sterilization purposes are usually less than 20 kGy. It was shown that gamma irradiation at 20 kGy had no or little adverse effects on PLA/P(VAc-co-VA) blends mechanical and gas barrier properties.

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

Highly filled biocomposites based on ethylene-vinyl acetate copolymer and wood flour

Science.gov (United States)

Shelenkov, P. G.; Pantyukhov, P. V.; Popov, A. A.

2018-05-01

Recently, there is a great interest in the world to biodegradable materials based on synthetic polymers in a composition with natural fillers. Highly filled polymer composite materials based on various grades of synthetic block copolymer of ethylene vinyl acetate with wood flour were under investigation. Five grades of ethylene-vinyl acetate copolymer differing in the content of vinyl acetate groups and a melt flow index were used in this work in order to find the best one for highly filled biocomposites. Wood flour content in biocomposites was 50, 60, 70 weight %. The rheological and physico-mechanical characteristics of the resulting biocomposites were studied.

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

OpenAIRE

Seong Baek Yang; Jong Won Kim; Jeong Hyun Yeum

2016-01-01

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 f...

Synthesis and structure of aromatic and heterocyclic tellurium compounds 33. Synthesis of [2-(aryltelluro)vinyl]aldehydes and ketones and stereochemistry of nucleophilic substitution under vinyl atom of carbon

International Nuclear Information System (INIS)

Sadekov, I.D.; Rivkin, B.B.; Zakharov, A.V.; Minkin, V.I.

1996-01-01

By means of interaction of (2-vinylchlorida) carbonyl compounds and (2-acylvinyl) triethylammonium chlorides and arenetellurolate-anions certain, [2-(aryltelluro)vinyl]ketones and [2-(aryltelluro)vinyl]aldehydes have been synthesized, while by means of reaction between 2-aroylvinyl chlorides and Li 2 Te some di(2-aroylvinyl)tellurides have been prepared. Interaction of (2-vinylchloride)ketones with arenetellurolate-anions always gives rise to Z-isomers of [2-(aryltelluro)vinyl]ketones as a result of stabilization of intermediate carbanion by intramolecular coordination O→Te. Nucleophilic addition of arenetellurolate-anions to α-acetylene aldehydes and ketones occurs as trans-addition. 36 refs., 2 figs., 1 tab

“Why is it that we can’t let go of the vinyl record?”

OpenAIRE

Julien, Olivier

2015-01-01

If one were to try to summarize Richard Osborne’s Vinyl: A History of the Analogue Record, we might describe it as an endeavour to discover what makes the vinyl disc record such a key medium in the determination of twentieth-century music by sound recording. As the author makes clear from the outset: “Although vinyl lost its status as Britain’s leading albums format as long ago as 1985 and thus looked set for a permanent decline, sales of vinyl LPs rose year on year by 43.7 per cent in 2011....

Graft copolymerization of vinyl monomers onto nylon 6 fibers by γ-ray pre-irradiation in air

International Nuclear Information System (INIS)

Iwasaki, Tatsuo; Ueda, Yoshitsugu

1992-01-01

Vinyl acetate, methyl methacrylate, alkyl acrylates, acrylonitrile, and acrylamide, were grafted onto nylon 6 fibers by the γ-ray pre-irradiation technique, and the effects of grafting on the microstructure and the mechanical properties of the graft copolymers were investigated. According to the analysis by wide-angle X-ray diffraction, the degree of crystallization decreased by increasing the percent graft of poly(vinyl acetate) in the grafted nylon 6 films. The mechanical parameters, such as the Young's modulus and the tensile strength at break, increased with increasing percent graft up to 50%. When percent grafting was smaller than 50%, rather homogeneous amorphous materials were obtained with vinyl acetate, while heterogeneous ones were obtained with other vinyl monomers. A poly(vinyl alcohol) grafted nylon 6 was obtained effectively by saponification of poly(vinyl acetate) grafted nylon 6, the former showing higher mechanical properties than the latter. Similar behavior was observed after saponification of the poly(methyl acrylate) grafted nylon 6. (author)

Preparation of vinyl chloride – vinyl ether copolymers via partial etherification from PVC

Directory of Open Access Journals (Sweden)

2007-08-01

Full Text Available The chemical modifications of poly (vinyl chloride with aliphatic and aromatic alcohols compounds have been investigated at room temperature and atmospheric pressure, catalysed by a new green basic catalyst, the Maghnite-K+. The presence of ether groups in the products is proven by infra red spectroscopy (IR as well as by nuclear magnetic resonance spectroscopy (1H NMR, and characterized by intrinsic viscosity as well as by gel permeation chromatography (GPC.

29 CFR 1926.1117 - Vinyl chloride.

Science.gov (United States)

2010-07-01

... 29 Labor 8 2010-07-01 2010-07-01 false Vinyl chloride. 1926.1117 Section 1926.1117 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... chloride. Note: The requirements applicable to construction work under this section are identical to those...

Flame retardant cotton fabrics by electron beam-induced polymerization of vinyl phosphonate oligomer

International Nuclear Information System (INIS)

Sawai, Takeshi; Ametani, Kazuo; Enomoto, Ichiro

1988-01-01

Vinyl phosphonate oligomer is presently used commercially as a cellulosic flame retardant in conjugation with N-methylol acrylamide, using a persulfate catalyst and a thermal cure. This combination can also be cured at room temperature with electron beams, as can the vinyl phosphonate alone. For the textile application, fixation of flame retardants by electron beams with low energy is one of the most promising applications. For the purpose of preparing flame resistant cotton fabrics such as bed sheets and pajamas, flame retardant curing of vinyl phosphonate oligomer on cotton fabrics was examined using electron beams from a self-sealed electron beam processor and gamma rays from a 60 Co source. A joint investigation was undertaken by the Tokyo Metropolitan Textile Research Institute and Tokyo Metropolitan Isotope Research Center to determine the feasibility of curing vinyl phosphonate oligomer on the cotton fabrics for textile finishing. (author)

Atmospheric fate of methyl vinyl ketone

DEFF Research Database (Denmark)

Praske, Eric; Crounse, John D; Bates, Kelvin H

2015-01-01

First generation product yields from the OH-initiated oxidation of methyl vinyl ketone (3-buten-2-one, MVK) under both low and high NO conditions are reported. In the low NO chemistry, three distinct reaction channels are identified leading to the formation of (1) OH, glycolaldehyde, and acetyl...

Optical Reading and Playing of Sound Signals from Vinyl Records

OpenAIRE

Hensman, Arnold; Casey, Kevin

2007-01-01

While advanced digital music systems such as compact disk players and MP3 have become the standard in sound reproduction technology, critics claim that conversion to digital often results in a loss of sound quality and richness. For this reason, vinyl records remain the medium of choice for many audiophiles involved in specialist areas. The waveform cut into a vinyl record is an exact replica of the analogue version from the original source. However, while some perceive this media as reproduc...

Controlled grafting of vinylic monomers on polyolefins: a robust mathematical modeling approach.

Science.gov (United States)

Saeb, Mohammad Reza; Rezaee, Babak; Shadman, Alireza; Formela, Krzysztof; Ahmadi, Zahed; Hemmati, Farkhondeh; Kermaniyan, Tayebeh Sadat; Mohammadi, Yousef

2017-01-01

Experimental and mathematical modeling analyses were used for controlling melt free-radical grafting of vinylic monomers on polyolefins and, thereby, reducing the disturbance of undesired cross-linking of polyolefins. Response surface, desirability function, and artificial intelligence methodologies were blended to modeling/optimization of grafting reaction in terms of vinylic monomer content, peroxide initiator concentration, and melt-processing time. An in-house code was developed based on artificial neural network that learns and mimics processing torque and grafting of glycidyl methacrylate (GMA) typical vinylic monomer on high-density polyethylene (HDPE). Application of response surface and desirability function enabled concurrent optimization of processing torque and GMA grafting on HDPE, through which we quantified for the first time competition between parallel reactions taking place during melt processing: (i) desirable grafting of GMA on HDPE; (ii) undesirable cross-linking of HDPE. The proposed robust mathematical modeling approach can precisely learn the behavior of grafting reaction of vinylic monomers on polyolefins and be placed into practice in finding exact operating condition needed for efficient grafting of reactive monomers on polyolefins.

Preparation of poly(vinyl alcohol)-grafted graphene oxide/poly(vinyl alcohol) nanocomposites via in-situ low-temperature emulsion polymerization and their thermal and mechanical characterization

Science.gov (United States)

Zhang, Shengchang; Liu, Pengqing; Zhao, Xiangsen; Xu, Jianjun

2017-02-01

An in-situ polymerization combined with chemical grafting modification method for preparing Poly(vinyl alcohol)-grafted graphene oxide/Poly(vinyl alcohol) (PVA-g-GO/PVA) nanocomposites was reported. Firstly, Poly(vinyl acetate)-grafted graphene oxide/Poly(vinyl acetate) nanocomposites were prepared, and then the PVA-g-GO/PVA nanocomposites could be obtained through alcoholysis reaction. X-ray photoelectron spectrometer and fourier-transform infrared spectrometer confirmed that the PVAc or PVA chains were successfully grafted to GO sheets during in-situ polymerization and alcoholysis. And the results from transmission electron microscopy, scanning electron microscopy and X-ray diffraction showed that the well compatibility and homogenous dispersion of PVA-g-GO in PVA matrix could be achieved. Differential scanning calorimetric, thermogravimetry analysis and tensile test were employed to study the thermal and mechanical properties of the PVA-g-GO/PVA nanocomposites. The results indicated that a 53% improvement of tensile strength and a 36% improvement of Young's modulus were achieved by addition of 0.5 wt% of GO sheets. And the glass transition temperature of PVA-g-GO/PVA nanocomposites was increased, and their thermal stability and crystallization degree were both decreased. Due to well dispersion of fillers and strong interfacial interactions at the filler-matrix interface, in-situ polymerization combined with chemical grafting modification was a good choice to prepare graphene/PVA nanocomposite with excellent mechanical properties.

Structure of chlorinated poly(vinyl chloride). III. Preparation of poly(vinyl chloride)-β,β-d2 as a model for the study of the mechanism of chlorination and of the chlorinated poly(vinyl chloride) structure

International Nuclear Information System (INIS)

Lukas, R.; Kolinsky, M.

1976-01-01

A method for the preparation of poly(vinyl chloride)-β,β-d 2 (PVC-β,β-d 2 ) as a model for the investigation of the mechanism of chlorination and of the CPVC structure has been suggested. The conditions of preparation of deuterated intermediates of a multistage synthesis of vinyl chloride-β,β-d 2 and of suspension-polymerized PVC-β,β-d 2 have been described including the mass balance. Malonic acid was used as the starting compound. Tacticity values of a sample of PVC-β,β-d 2 and its infrared and nuclear magnetic resonance (NMR) spectra are presented and compared with the data already published

(e,2e) momentum spectroscopic study of the C=C π orbitals of the vinyl halides

International Nuclear Information System (INIS)

Gorunganthu, R.R.; Coplan, M.A.; Leung, K.T.; Tossell, J.A.; Moore, J.H.; Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada; Department of Chemistry, University of Maryland, College Park, Maryland 20742)

1989-01-01

The distribution of electron momentum density has been measured for the outermost occupied orbitals of the vinyl halides and ethylene using the (e,2e) technique. In contrast to the ionization potentials for these π orbitals which decrease monotonically from vinyl fluoride to vinyl iodide, the values of the momenta where the distributions are a maximum, p max , increase from the fluoride through the bromide and then shift back to a lower value for the iodide. This observation can be analyzed in terms of B(r), the Fourier transform of the observed momentum distribution, and ΔB(r), the difference between B(r) functions. The shape of ΔB(r) for the fluoride, chloride, and bromide in comparison to ethylene reflects the effect of the carbon--halogen antibonding interaction in these vinyl halides. On the other hand, in vinyl iodide the antibonding interaction is compensated for by the diffuse iodine 5p character of the molecular orbital. The relation of these observations to chemical properties of the vinyl halides is discussed along with differences between experiment and calculations at low momentum

Decontamination efficiency of a sheet of vinyl wall paper as a surface material in radioisotope laboratory

International Nuclear Information System (INIS)

Furukawa, Kazuhiko; Funadera, Kanako

1989-01-01

It has long been desired to prevent surface materials from cracking in a radioisotope laboratory. We applied a sheet of nonflammable wall paper, vinyl cloth, as a surface material to cover concrete wall. It was sufficiently resistant to the reinforced concrete wall cracking. The efficiency of the decontamination of the vinyl cloth was compared with those of stainless steel, iron and painted plates. The contamination and decontamination indices were determined in these surface materials after contamination with [ 32 P]orthophosphate (pH 3, 7 and 11) for 0 to 48 h. Both of the indices of the vinyl cloth were higher than those of the other materials. Further, it was confirmed that the vinyl cloth was resistant to acid and alkaline conditions and radioisotopes could not be permeable. The wipe off efficiency was also investigated in these materials by use of several decontamination detergents. In any reagents tested, the wipe of efficiency of the vinyl cloth was more than 80%. Thus, the vinyl cloth could be used for the surface material and is one of good surface materials in a radioisotope laboratory. (author)

Synthesis of tritium labelled methyl vinyl ketone and its use in copolymer analysis

International Nuclear Information System (INIS)

Burfield, D.R.; Savariar, C.M.

1980-01-01

The synthesis of tritiated methyl vinyl ketone by base catalysed exchange and its use in determining the ketone content of styrene/methyl vinyl ketone copolymers are reported. Methods of assay are described in detail and the general applicability of the method is discussed. (author)

Impact of Industrial Grade Modified PVA to Vinyl Acetate Semi-continuous Emulsion Polymerization and Properties of Final Product

Directory of Open Access Journals (Sweden)

Mindaugas DUBININKAS

2013-03-01

Full Text Available Successful vinyl acetate radical emulsion polymerization in water with different type of industrial grade poly(vinyl alcohol were produced by semi continuous way. The poly(vinyl alcohol type has crucial impact on dispersion rheological as well on films and bonding strength properties. It should be stated that the films containing modified poly (vinyl alcohol has better water resistance and mechanical properties. Poly(vinyl alcohol with higher ethylene moieties content and high hydrolization degree determines extremely low viscosity of final dispersion.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3823

Radiation chemical grafting of vinyl acetate and styrene on nitrocellulose

International Nuclear Information System (INIS)

Chapiro, A.; Foex, M.; Jendrychowska-Bonamour, A.M.

1977-01-01

Vinyl acetate and styrene were grafted onto nitrocellulose using the direct radiation grafting technique with 500 and 3000 Ci 60 Co γ sources. For vinyl acetate, the reaction proceeds homogeneously. The kinetics are dominated by degradative chain transfer to the nitrocellulose. The polymerization of vinyl acetate was examined in the presence of isoamyl nitrate, a model for nitrocellulose; the transfer constant was determined and the results are treated semi-quantitatively. For styrene, grafting occurs in a swollen film irradiated in the presence of excess monomer. The diffusion of styrene into nitrocellulose is extremely slow; methanol was added to the reaction mixture to favour diffusion which was found to obey Fick's law. The diffusion constant and activation energy of diffusion are evaluated. The grafting kinetics are controlled by monomer diffusion, accounting for the increase of dose-rate exponent with temperature. A spontaneous grafting process occurs in the absence of irradiation. It is initiated by macroradicals arising from thermal decomposition of nitrocellulose. (author)

Scientists Toast the Discovery of Vinyl Alcohol in Interstellar Space

Science.gov (United States)

2001-10-01

Astronomers using the National Science Foundation's 12 Meter Telescope at Kitt Peak, AZ, have discovered the complex organic molecule vinyl alcohol in an interstellar cloud of dust and gas near the center of the Milky Way Galaxy. The discovery of this long-sought compound could reveal tantalizing clues to the mysterious origin of complex organic molecules in space. Vinyl Alcohol and its fellow isomers "The discovery of vinyl alcohol is significant," said Barry Turner, a scientist at the National Radio Astronomy Observatory (NRAO) in Charlottesville, Va., "because it gives us an important tool for understanding the formation of complex organic compounds in interstellar space. It may also help us better understand how life might arise elsewhere in the Cosmos." Vinyl alcohol is an important intermediary in many organic chemistry reactions on Earth, and the last of the three stable members of the C2H4O group of isomers (molecules with the same atoms, but in different arrangements) to be discovered in interstellar space. Turner and his colleague A. J. Apponi of the University of Arizona's Steward Observatory in Tucson detected the vinyl alcohol in Sagittarius B -- a massive molecular cloud located some 26,000 light-years from Earth near the center of our Galaxy. The astronomers were able to detect the specific radio signature of vinyl alcohol during the observational period of May and June of 2001. Their results have been accepted for publication in the Astrophysical Journal Letters. Of the approximately 125 molecules detected in interstellar space, scientists believe that most are formed by gas-phase chemistry, in which smaller molecules (and occasionally atoms) manage to "lock horns" when they collide in space. This process, though efficient at creating simple molecules, cannot explain how vinyl alcohol and other complex chemicals are formed in detectable amounts. For many years now, scientists have been searching for the right mechanism to explain how the building

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

Separator Membrane from Crosslinked Poly(Vinyl Alcohol and Poly(Methyl Vinyl Ether-alt-Maleic Anhydride

Directory of Open Access Journals (Sweden)

Charu Vashisth Rohatgi

2015-03-01

Full Text Available In this work, we report separator membranes from crosslinking of two polymers, such as poly vinyl alcohol (PVA with an ionic polymer poly(methyl vinyl ether-alt-maleic anhydride (PMVE-MA. Such interpolymer-networked systems were extensively used for biomedical and desalination applications but they were not examined for their potential use as membranes or separators for batteries. Therefore, the chemical interactions between these two polymers and the influence of such crosslinking on physicochemical properties of the membrane are systematically investigated through rheology and by critical gel point study. The hydrogen bonding and the chemical interaction between PMVE-MA and PVA resulted in highly cross-linked membranes. Effect of the molecular weight of PVA on the membrane properties was also examined. The developed membranes were extensively characterized by studying their physicochemical properties (water uptake, swelling ratio, and conductivity, thermal and electrochemical properties using differential scanning calorimetry (DSC, dynamic mechanical analysis (DMA, thermo-gravimetric analysis (TGA and electrochemical impedance spectroscopy (EIS. The DSC study shows the presence of a single Tg in the membranes indicating compatibility of the two polymers in flexible and transparent films. The membranes show good stability and ion conductivity suitable for separator applications.

Separator Membrane from Crosslinked Poly(Vinyl Alcohol) and Poly(Methyl Vinyl Ether-alt-Maleic Anhydride)

Science.gov (United States)

Rohatgi, Charu Vashisth; Dutta, Naba K.; Choudhury, Namita Roy

2015-01-01

In this work, we report separator membranes from crosslinking of two polymers, such as poly vinyl alcohol (PVA) with an ionic polymer poly(methyl vinyl ether-alt-maleic anhydride) (PMVE-MA). Such interpolymer-networked systems were extensively used for biomedical and desalination applications but they were not examined for their potential use as membranes or separators for batteries. Therefore, the chemical interactions between these two polymers and the influence of such crosslinking on physicochemical properties of the membrane are systematically investigated through rheology and by critical gel point study. The hydrogen bonding and the chemical interaction between PMVE-MA and PVA resulted in highly cross-linked membranes. Effect of the molecular weight of PVA on the membrane properties was also examined. The developed membranes were extensively characterized by studying their physicochemical properties (water uptake, swelling ratio, and conductivity), thermal and electrochemical properties using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermo-gravimetric analysis (TGA) and electrochemical impedance spectroscopy (EIS). The DSC study shows the presence of a single Tg in the membranes indicating compatibility of the two polymers in flexible and transparent films. The membranes show good stability and ion conductivity suitable for separator applications. PMID:28347019

Proton NMR study of the influence of heme vinyl groups on the formation of the isomeric forms of sulfmyoglobin

International Nuclear Information System (INIS)

Chatfield, M.J.; La Mar, G.N.; Balch, A.L.; Smith, K.M.; Parish, D.W.; LePage, T.J.

1986-01-01

The formation of sulfmyoglobin has been investigated for myoglobin reconstituted with hemins having vinyls replaced by hydrogens to determine the participation of the vinyl groups in the reaction processes. Green complexes are produced in all cases, proving that vinyls are not obligatory for the formation of sulfproteins. In the presence of the 4-vinyl group, the 1 H NMR spectra of the met-cyano derivatives indicate the formation of three green species; however, the most stable of these products is not formed in the absence of this group, confirming reaction of the 4-vinyl in this species. Two new red extractable sulfmyoglobin derivatives are formed in the absence of the 4-vinyl group. (Auth.)

21 CFR 178.3790 - Polymer modifiers in semirigid and rigid vinyl chloride plastics.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polymer modifiers in semirigid and rigid vinyl...: ADJUVANTS, PRODUCTION AIDS, AND SANITIZERS Certain Adjuvants and Production Aids § 178.3790 Polymer modifiers in semirigid and rigid vinyl chloride plastics. The polymers identified in paragraph (a) of this...

Synthesis and luminescence properties of tris(bipyridine)ruthenium(II)-containing vinyl polymers

International Nuclear Information System (INIS)

Furue, Masaoki; Sumi, Katsuhiro; Nozakura, Shun-ichi

1981-01-01

The luminescence properties of poly[Ru(bpy) 2 (6-vinyl-bpy)-co-6-vinyl-bpy], (I) were compared with those of Ru(bpy) 3 2+ at 77 - 298 K. A larger depletion of luminescence intensity and lifetime was observed in I in fluid solution. The dynamic quenching processes were suggested to be the dominant factor for the energy dissipation in I. (author)

Effect of various solvents on the viscosity-average molecular weight of poly (vinyl acetate)

International Nuclear Information System (INIS)

Rehman, W.U.; But, M.A.; Chughtai, A.; Jamil, T.; Sattar, A.

2006-01-01

Solution polymerization of Vinyl Acetate was carried out in various solvents (benzene, toluene, ethyl acetate, acetonitrile). Dilute solution viscometry was used to determine the viscosity-average molecular weight of the resulting Poly (Vinyl Acetate) (PV Ac) in each case. The viscosity-average molecular weight (M,J of PVAc was found to increase in the order benzene < toluene < ethyl acetate < acetonitrile, It was concluded that under the same reaction conditions (polymerization time, initiator quantity, solvent/monomer ratio, temperature), acetonitrile served as the best solvent for solution. polymerization of Vinyl Acetate monomer. (author)

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

Deutsches Institut für Normung. Berlin

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

Preparation of vinyl acetate grafted natural rubber by irradiation method

Energy Technology Data Exchange (ETDEWEB)

Porntrairat, A.; Pattamaprom, C. [Center of Excellence on Natural Rubber Technology, Department of Chemical Engineering, Faculty of Engineering, Thammasat University, Pathumthani 12120 (Thailand)

2016-03-09

Improvement in properties of natural rubber could be done by several methods. In this research, gamma radiation technique, which is simple, accurate, easy to control and clean, was applied to enhance the properties of natural rubber (NR) in latex state. The purpose of this research is to study the appropriate condition for preparing grafted natural rubber latex by using irradiation method. Vinyl acetate monomers (VAc) were grafted onto natural rubber latex (NR-g-PVAc) at 0-10 kGys by gamma radiation from Cobalt-60 source at room temperature. Physical properties of grafted natural rubber such as chloroform number, swelling ratio and gel content were measured. The VAc content of NR-g-PVAc was investigated by titration and visualized by FTIR spectroscopy. The FTIR spectra of NR-g-PVAc prepared at 0-10 kGys showed characteristic peaks of the vinyl acetate confirming that VAc could be grafted onto natural rubber molecular chains effectively under appropriate irradiation conditions. From the result, radiation grafting was found to be a useful technique for grafting of vinyl acetate onto natural rubber.

Inactivation of γ-aminobutyric acid aminotransferase by γ-ethynyl- and γ-vinyl GABA

International Nuclear Information System (INIS)

Silverman, R.B.; Burke, J.R.; Nanavati, S.M.

1989-01-01

γ-Ethynyl- and γ-vinyl GABA (vigabatrin) are anticonvulsant agents that have been shown to be mechanism-based inactivators of γ-aminobutyric acid aminotransferase (GABA-T). The inactivation mechanisms of these compounds have been investigated. Inactivation of GABA-T by [ 3 H]γ-ethynyl GABA led to the incorporation of 1.0 equiv of 3 H into the enzyme which is not released by enzyme denaturation. Inactivation by γ-ethynyl GABA of GABA-T reconstituted with [ 3 H]PLP followed by denaturation resulted in release of 3 H as PLP. Eight different possible adducts are consistent with that result. Experiments have been carried out to differentiate these possibilities. Similar studies have been carried out with γ-vinyl GABA. Inactivation by [ 14 C]γ-vinyl GABA resulted in the incorporation of 1.0 equiv of 14 C per active site. Unlike the case with γ-ethynyl GABA, γ-vinyl GABA inactivation of GABA-T reconstituted with [ 3 H]PLP followed by denaturation resulted in release of 3 H as PMP

Rearing of germfree chicks in a vinyl isolator

International Nuclear Information System (INIS)

Ishibashi, Teru; Kametaka, Masao; Ozaki, Akira; Yamamoto, Tetsuzo; Kaneuchi, Choji.

1977-01-01

A method of rearing germfree chicks in a vinyl isolator was developed, Hatchability of eggs was higher than 95% when eggs were sterilized in a 1.5% mercuric chloride solution on the 2nd day before hatching. Sterility was 93% when 5 to 10 chicks were reared in a vinyl isolator for 2 weeks. Depression of body weight gain was observed in chicks fed diet irradiated at higher than 4 Mrad. However, no effects of irradiation on chick growth were observed when fat and the other components were sterilized separately and mixed before feeding. The growth rates of germfree chicks were higher than those of the conventional chicks which were supplied a diluted solution of fresh cecum feces of young hens with a normal intestinal flora pattern at the first feeding. (auth.)

γ-Rays-induced synthesis of hydrogels of vinyl ethers with stimuli-sensitive behavior

International Nuclear Information System (INIS)

Nam, I.K.; Mun, G.A.; Urkimbaeva, P.I.; Nurkeeva, Z.S.

2003-01-01

γ-Radiation method was applied to synthesize novel water-soluble and water-swelling polymers. Vinyl ether of ethylene glycol (VEEG), vinyl butyl (VBE) and vinyl isobutyl (VIBE) ethers were used as monomers. The synthesis of VEEG-VBE and VEEG-VIBE copolymers was carried out in a wide range of feed composition and absorbed dose. It was found that the hydrophobic-hydrophilic balance of the copolymers could be delicately varied by the copolymer composition as well as by the chemical structure of the alkyl substitute in the hydrophobic moiety. The copolymers exhibit thermo-sensitive behavior in water solutions. The value of transition temperature is considerably decreased at a higher concentration of the hydrophobic component in the copolymer composition

A Kinetic Study of the Emulsion Polymerization of Vinyl Acetate

DEFF Research Database (Denmark)

Friis, N.; Nyhagen, L.

1973-01-01

The emulsion polymerization of vinyl acetate was studied at 50°C. It was found that the rate of polymerization was proportional to the 0.5 power of the initiator concentration and the 0.25 power of the number of particles. The number of particles was proportional to the power 0.5 ± 0.......05 of the emulsifier concentration, but independent of the initiator concentration. The limiting viscosity number of the polymers produced was independent of the initiator concentration and number of polymer particles. It is suggested that the mechanism of vinyl acetate emulsion polymerization is similar...

Synthesis and characterization of copolymers from hindered amines and vinyl monomers

Directory of Open Access Journals (Sweden)

Marcelo Aparecido Chinelatto

2014-01-01

Full Text Available New copolymers from hindered amines and vinyl monomers were synthesized by radical chain polymerization. To obtain polymeric HALS, acrylamide-(1ATP and acrylate-(4ATP monomers, derivatives from 2,2,6,6-tetramethylpiperidine and 2,2,6,6-tetramethyl-4-piperidinol were synthesized. The radical chain polymerization of 1ATP with styrene (Sty using 1-butanethiol (BTN resulted in a copolymer with 95 units of Sty and 15 units of 1ATP. The radical chain polymerization of 1ATP and vinyl acetate (VAc has produced only 1ATP homopolymer. In the chain polymerization of 4ATP with Sty or VAc, the hydrogen atom bonded to the nitrogen of 4ATP is labile enough to originate another radical at this site. The steric hindrance imposed by methyl groups on this bonding site hampers its reaction with other propagating species and the formation of a copolymer or network structure will be dependent on the size of the pendent group in the vinyl monomer.

The breakdown of vinyl ethers as a two-center synchronous reaction

Science.gov (United States)

Pokidova, T. S.; Shestakov, A. F.

2009-11-01

The experimental data on the molecular decomposition of vinyl ethers of various structures to alkanes and the corresponding aldehydes or ketones in the gas phase were analyzed using the method of intersecting parabolas. The enthalpies and kinetic parameters of decomposition were calculated for 17 reactions. The breakdown of ethers is a two-center concerted reaction characterized by a very high classical potential barrier to the thermally neutral reaction (180-190 kJ/mol). The kinetic parameters (activation energies and rate constants) of back reactions of the formation of vinyl ethers in the addition of aldehydes or ketones to alkanes were calculated using the method of intersecting parabolas. The factors that influenced the activation energy of the decomposition and formation of ethers were discussed. Quantum-chemical calculations of several vinyl ether decomposition reactions were performed. Ether formation reactions were compared with the formation of unsaturated alcohols as competitive reactions, which can occur in the interaction of carbonyl compounds with alkenes.

Nanoscale Characterization of Glass Flake Filled Vinyl Ester Anti-Corrosion Coatings

Directory of Open Access Journals (Sweden)

Salim Barbhuiya

2017-08-01

Full Text Available Vinyl ester is a thermoset matrix resin that is widely used in the coating industry. The presence of glass flakes further enhances the anti-corrosion performance of this coating. This paper reports the nanoscaled characterization of glass flake filled vinyl ester anti-corrosion coatings on mild steel. Bond strength properties of one uncoated and four coated samples with different thicknesses (300, 600, 900 and 1200 μm were studied using nanoscratch technique and ASTM Standard Test. It was found that the bond strength of coating with thickness 900 μm was the highest. The frequency distributions of elastic modulus on coating with 900 μm thickness determined using nanoindentation indicated that only 20–25% of the coating is composed of glass flakes and the balance is vinyl ester matrix. The critical depth at which the material is subject to failure due to external load and abrasion, was found to be around 100 nm.

Emission and Mechanical Evaluations of Vinyl-Ester Resin Systems

National Research Council Canada - National Science Library

Sands, James

2003-01-01

Vinyl-ester resins (VE) are frequently used in liquid molding of composite materials for several applications including naval and army structures, commercial boat manufacturing, and building construction...

Acute effects of sodium valproate and gamma-vinyl GABA on regional amino acid metabolism in the rat brain: incorporation of 2-[14C]glucose into amino acids.

Science.gov (United States)

Chapman, A G; Riley, K; Evans, M C; Meldrum, B S

1982-09-01

Amino acid concentrations have been determined in rat brain regions (cortex, striatum, cerebellum, and hippocampus) by HPLC after administration of acute anticonvulsant doses of sodium valproate (400 mg/kg, i.p.) and gamma-vinyl-GABA (1 g/kg, i.p.). After valproate administration the GABA level increases only in the cortex; aspartic acid concentration decreases in the cortex and hippocampus, and glutamic acid decreases in the hippocampus and striatum and increases in the cortex and cerebellum. There are no changes in the concentrations of glutamine, taurine, glycine, serine, and alanine following valproate administration. Only the GABA level increases in all the regions after gamma-vinyl-GABA administration. Cortical analyses 2, 4 and 10 minutes after pulse labeling with 2-[14C]glucose, i.v., show no change in the rate of cortical glucose utilization in the valproate treated group. The rate of labeling of glutamic acid is also unchanged, but the rate of labeling of GABA is reduced following valproate administration. After gamma-vinyl-GABA administration there is no change in the rate of labeling of GABA. These biochemical findings can be interpreted in terms of a primary anticonvulsant action of valproate on membrane receptors with secondary effects on the metabolism of amino acid neurotransmitters. This contrasts with the primary action of gamma-vinyl-GABA on GABA-transaminase activity.

Laser induced augmentation of silver nanospheres to nanowires in ethanol fostered by Poly Vinyl Pyrrolidone

Energy Technology Data Exchange (ETDEWEB)

Sebastian, Suneetha, E-mail: sunikutty@gmail.com; Linslal, C.L.; Vallabhan, C.P.G.; Nampoori, V.P.N.; Radhakrishnan, P.; Kailasnath, M.

2014-11-30

Highlights: • Silver nanospheres are synthesised in ethanol containing Poly Vinyl Pyrrolidone which acts as a polymeric capping agent to nanoparticles thus improving its stability. • Laser irradiation onto the colloidal solution of silver nanoparticles produced well defined nanowires through ripening mechanism promoted by Poly Vinyl Pyrrolidone. • Nanowires so formed are having an average length of 8.7 μm and width of 160 nm. - Abstract: Stable uniform silver nanospheres having an average diameter of 45 nm are synthesised in ethanol containing Poly Vinyl Pyrrolidone using Laser Ablation in Liquid technique. Further irradiation of the nanocolloidal solution by focussed laser beam produced stable well defined silver nanowires through ripening mechanism fostered by the presence of Poly Vinyl Pyrrolidone. Confirmation of the mechanism is obtained from Transmission Electron Microscopic images of the nanocolloidal solution irradiated for different time durations.

Electrodialytic Transport Properties of Anion-Exchange Membranes Prepared from Poly(vinyl alcohol) and Poly(vinyl alcohol-co-methacryloyl aminopropyl trimethyl ammonium chloride).

Science.gov (United States)

Jikihara, Atsushi; Ohashi, Reina; Kakihana, Yuriko; Higa, Mitsuru; Kobayashi, Kenichi

2013-01-02

Random-type anion-exchange membranes (AEMs) have been prepared by blending poly(vinyl alcohol) (PVA) and the random copolymer-type polycation, poly(vinyl alcohol-co-methacryloyl aminopropyl trimethyl ammonium chloride) at various molar percentages of anion-exchange groups to vinyl alcohol groups, Cpc, and by cross-linking the PVA chains with glutaraldehyde (GA) solution at various GA concentrations, CGA. The characteristics of the random-type AEMs were compared with blend-type AEMs prepared in our previous study. At equal molar percentages of the anion exchange groups, the water content of the random-type AEMs was lower than that of the blend-type AEMs. The effective charge density of the random-type AEMs increased with increasing Cpc and reached a maximum value. Further, the maximum value of the effective charge density increased with increasing CGA. The maximum value of the effective charge density, 0.42 mol/dm3, was obtained for the random-type AEM with Cpc = 4.2 mol % and CGA = 0.15 vol %. A comparison of the random-type and blend-type AEMs with almost the same Cpc showed that the random-type AEMs had lower membrane resistance than the blend-type ones. The membrane resistance and dynamic transport number of the random-type AEM with Cpc = 6.0 mol % and CGA = 0.15 vol % were 4.8 Ω cm2 and 0.83, respectively.

Vinyl flooring in the home is associated with children's airborne butylbenzyl phthalate and urinary metabolite concentrations.

Science.gov (United States)

Just, Allan C; Miller, Rachel L; Perzanowski, Matthew S; Rundle, Andrew G; Chen, Qixuan; Jung, Kyung Hwa; Hoepner, Lori; Camann, David E; Calafat, Antonia M; Perera, Frederica P; Whyatt, Robin M

2015-01-01

Prior studies have shown that vinyl flooring as well as the vinyl-softening plasticizers butylbenzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP) are associated with asthma and airway inflammation. Although DEHP exposure is primarily dietary, whether home vinyl flooring contributes to indoor air and urinary metabolite concentrations for these two phthalates is unclear. Exposures to BBzP and DEHP were examined in a prospective birth cohort of New York City children (n=239) using: (i) visual observation of potential phthalate containing flooring, (ii) a 2-week home indoor air sample, and (iii) concurrent urinary metabolites in a subset (n=193). The category "vinyl or linoleum" flooring was observed in 135 (56%) of monitored rooms; these rooms had statistically significantly higher indoor air geometric mean concentrations of BBzP (23.9 ng/m(3)) than rooms with wood or carpet flooring (10.6 ng/m(3)). Children from homes with "vinyl or linoleum" flooring also had significantly higher urinary BBzP metabolite concentrations than other children. Indoor air BBzP and urinary metabolite concentrations were correlated positively (Spearman's rho 0.40). By contrast, indoor air DEHP was not associated with flooring type nor with its urinary metabolite concentrations. Vinyl flooring in the home may be an important source of children's exposure to BBzP via indoor air.

Crystallisation of hydroxyapatite in phosphorylated poly(vinyl alcohol) as a synthetic route to tough mechanical hybrid materials

International Nuclear Information System (INIS)

Kusakabe, Akane; Hirota, Ken; Mizutani, Tadashi

2017-01-01

Partially phosphorylated poly(vinyl alcohol) was prepared by treating poly(vinyl alcohol) with 100% phosphoric acid, and 5, 10 and 20% of the hydroxyl groups were converted to phosphoric acid ester. Addition of Ca 2+ to an aqueous solution of phosphorylated poly(vinyl alcohol) gave a transparent gel. Five cycles of alternate soaking of the gel in aqueous CaCl 2 and aqueous (NH 4 ) 2 HPO 4 were carried out to crystallise hydroxyapatite (HAP) in the phosphorylated poly(vinyl alcohol) matrix. The X-ray diffraction peaks of HAP formed in 5% phosphorylated PVA were sharp, while those of HAP formed in 20% phosphorylated PVA were broad. The contents of inorganic phase in the hybrid powder were increased from 58 to 76 wt% as the fraction of phosphate groups in the gel was decreased from 20% to 5%. The hybrid powder was first subjected to uniaxial pressing, followed by cold isostatic pressing (CIP) and warm isostatic pressing (WIP) at 120 °C at pressures of 300–980 MPa, to obtain the specimens for three-point bending test. These hybrid specimens showed bending strengths of 15–53 MPa. The hybrid compacts prepared from 10% phosphorylated poly(vinyl alcohol) showed the smallest Young's modulus, the largest displacement at break, and the largest fracture energy, showing that it has the highest toughness among the hybrid materials prepared from poly(vinyl alcohol) with varying degrees of phosphorylation. - Graphical abstract: Densification of hydroxyapatite crystallised in 10% phosphorylated poly(vinyl alcohol) gave the toughest compact. - Highlights: • Hydroxyapatite was crystallised in phosphorylated poly(vinyl alcohol) gels. • Crystallite size of hydroxyapatite decreased as phosphate density was increased. • The hybrid specimens prepared in 10% phosphorylated gel was the toughest. • Phosphate density in organic matrix regulated the mechanical properties of the hybrid.

Crystallisation of hydroxyapatite in phosphorylated poly(vinyl alcohol) as a synthetic route to tough mechanical hybrid materials

Energy Technology Data Exchange (ETDEWEB)

Kusakabe, Akane; Hirota, Ken; Mizutani, Tadashi, E-mail: tmizutan@mail.doshisha.ac.jp

2017-01-01

Partially phosphorylated poly(vinyl alcohol) was prepared by treating poly(vinyl alcohol) with 100% phosphoric acid, and 5, 10 and 20% of the hydroxyl groups were converted to phosphoric acid ester. Addition of Ca{sup 2+} to an aqueous solution of phosphorylated poly(vinyl alcohol) gave a transparent gel. Five cycles of alternate soaking of the gel in aqueous CaCl{sub 2} and aqueous (NH{sub 4}){sub 2}HPO{sub 4} were carried out to crystallise hydroxyapatite (HAP) in the phosphorylated poly(vinyl alcohol) matrix. The X-ray diffraction peaks of HAP formed in 5% phosphorylated PVA were sharp, while those of HAP formed in 20% phosphorylated PVA were broad. The contents of inorganic phase in the hybrid powder were increased from 58 to 76 wt% as the fraction of phosphate groups in the gel was decreased from 20% to 5%. The hybrid powder was first subjected to uniaxial pressing, followed by cold isostatic pressing (CIP) and warm isostatic pressing (WIP) at 120 °C at pressures of 300–980 MPa, to obtain the specimens for three-point bending test. These hybrid specimens showed bending strengths of 15–53 MPa. The hybrid compacts prepared from 10% phosphorylated poly(vinyl alcohol) showed the smallest Young's modulus, the largest displacement at break, and the largest fracture energy, showing that it has the highest toughness among the hybrid materials prepared from poly(vinyl alcohol) with varying degrees of phosphorylation. - Graphical abstract: Densification of hydroxyapatite crystallised in 10% phosphorylated poly(vinyl alcohol) gave the toughest compact. - Highlights: • Hydroxyapatite was crystallised in phosphorylated poly(vinyl alcohol) gels. • Crystallite size of hydroxyapatite decreased as phosphate density was increased. • The hybrid specimens prepared in 10% phosphorylated gel was the toughest. • Phosphate density in organic matrix regulated the mechanical properties of the hybrid.

Characterization of an H2-utilizing enrichment culture that reductively dechlorinates tetrachloroethene to vinyl chloride and ethene in the absence of methanogenesis and acetogenesis.

OpenAIRE

Maymó-Gatell, X; Tandoi, V; Gossett, J M; Zinder, S H

1995-01-01

We have been studying an anaerobic enrichment culture which, by using methanol as an electron donor, dechlorinates tetrachloroethene (PCE) to vinyl chloride and ethene. Our previous results indicated that H2 was the direct electron donor for rductive dechlorination of PCE by the methanol-PCE culture. Most-probable-number counts performed on this culture indicated low numbers ( or equal to 10(6)/ml...

Radiation polymerization of 2-hydroxyethyl methacrylate-vinyl pyrrolidone-water system

International Nuclear Information System (INIS)

Kumakura, M.; Kaetsu, I.

1988-01-01

Polymerization was studied using mixtures of 2-hydroxyethyl methacrylate(HEMA)-water, vinyl pyrrolidone(NVP)-water and 2-hydroxyethyl methacrylate-vinyl pyrrolidone-water. The mixtures were irradiated with gamma radiation from a 60 Co source. Irradiation was carried out at temperatures of 0, -24, -45, -63, -78, and -196 degC. The dependence was studied of the polymerization rate on temperature during irradiation for the individual mixtures, as were the effect of monomer composition on the polymerization of the HEMA-NVP-water system at 0 degC, the effect of water on NVP polymerization and the relationship between water absorption and the composition of the monomer. (E.S.). 4 figs., 6 refs

An Evaluation of Fracture Toughness of Vinyl Ester Composites Cured under Microwave Conditions

Science.gov (United States)

Ku, H.; Chan, W. L.; Trada, M.; Baddeley, D.

2007-12-01

The shrinkage of vinyl ester particulate composites has been reduced by curing the resins under microwave conditions. The reduction in the shrinkage of the resins by microwaves will enable the manufacture of large vinyl ester composite items possible (H.S. Ku, G. Van Erp, J.A.R. Ball, and S. Ayers, Shrinkage Reduction of Thermoset Fibre Composites during Hardening using Microwaves Irradiation for Curing, Proceedings, Second World Engineering Congress, Kuching, Malaysia, 2002a, 22-25 July, p 177-182; H.S. Ku, Risks Involved in Curing Vinyl Ester Resins Using Microwaves Irradiation. J. Mater. Synth. Proces. 2002b, 10(2), p 97-106; S.H. Ku, Curing Vinyl Ester Particle Reinforced Composites Using Microwaves. J. Comp. Mater., (2003a), 37(22), p 2027-2042; S.H. Ku and E. Siores, Shrinkage Reduction of Thermoset Matrix Particle Reinforced Composites During Hardening Using Microwaves Irradiation, Trans. Hong Kong Inst. Eng., 2004, 11(3), p 29-34). In tensile tests, the yield strengths of samples cured under microwave conditions obtained are within 5% of those obtained by ambient curing; it is also found that with 180 W microwave power, the tensile strengths obtained for all duration of exposure to microwaves are also within the 5% of those obtained by ambient curing. While, with 360 W microwave power, the tensile strengths obtained for all duration of exposure to microwaves are 5% higher than those obtained by ambient curing. Whereas, with 540 W microwave power, the tensile strengths obtained for most samples are 5% below those obtained by ambient curing (H. Ku, V.C. Puttgunta, and M. Trada, Young’s Modulus of Vinyl Ester Composites Cured by Microwave Irradiation: Preliminary Results, J. Electromagnet. Waves Appl., 2007, 20(14), p. 1911-1924). This project, using 33% by weight fly ash reinforced vinyl ester composite [VE/FLYSH (33%)], is to further investigate the difference in fracture toughness between microwave cured vinyl ester particulate composites and those cured

Rheological properties of poly-vinyl-chloride solutions in varioussolvents

International Nuclear Information System (INIS)

Kurbanaliev, M.K.; Narzullaev, B.N.; Dustov, I.K.; Marupov, R.M.

1976-01-01

The present article is the result of studying of curves process ofpoly-vinyl-chloride solutions in wide interval of tension and velocities ofshear in thermodynamically good and bad solvents at various temperatures

Controlled synthesis of novel 3D dendritic Bi2S3 /cross-linked poly(vinyl alcohol) nanocomposites

International Nuclear Information System (INIS)

Wu, W-T; Shi Lei; Pang Wenmin; Wang Yusong; Zhu Qingren; Xu Guoyong

2006-01-01

Novel spherical three-dimensional (3D) dendritic Bi 2 S 3 /cross-linked poly(vinyl alcohol) (PVA) nanocomposites were successfully synthesized in aqueous solution of amphiphilic polyvinylacetone (PVKA) (ketalization degree D H = 0.549), via one-step in situ decomposition of the complex [Bi(Tu) x ] 3+ under γ-ray irradiation, utilizing the controllable hydrolysis property of PVKA in acidic solution. Herein, PVA chains are obtained from the hydrolysed PVKA. These uniform 3D spherical nanocomposites have a structure similar to that found in the natural lotus leaf, where every microscale papilla on the leaf surface is covered by nanoscale papillae

APPLICATION OF TRITON X-100 COATED POLY VINYL ...

African Journals Online (AJOL)

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and Zn(II) ions based on the uptake of their complexes with ... The presence of heavy metals in ... Poly vinyl chloride high molecular weight was purchased .... 7.0 and then the charge intensity of the functional groups of solid materials played a ...

Antioxidant Microemulsion-based Ethylene Vinyl Acetate Film Containing Mangiferin and Surfactants

Directory of Open Access Journals (Sweden)

Boonnattakorn Rungkan

2016-01-01

Full Text Available Mangiferin, a natural antioxidant additive, was incorporated into an ethylene vinyl acetate copolymer (EVA containing 18% vinyl acetate (VA using the emulsion solvent evaporation technique. Sorbitan ester (Span®20 and polymeric surfactant (Pluronic®P−123 were compared. Mangiferin was finely dispersed in the suspension with the addition of surfactants studied. Span®20 was chosen as the surfactant for film preparation in the next step due to the dispersing and film forming properties. Effects of vinyl acetate (VA contents on the film properties were investigated. The EVA films with 12% VA had the highest tensile strength and oxygen barrier, followed by 18, 25 and 40% VA, respectively. Addition of Span®20 had only a slight effect on mechanical and barrier properties of the films, but markedly increased the release of mangiferin from the EVA matrices except in the 40% VA films. The maximum concentrations of mangiferin released from the 40, 25, 18 and 12% VA films into 95% ethanol were 83.30, 66.84, 51.77 and 34.57 μg·mL−11, respectively. The release concentrations from the 40 and 25% VA films was 2.4 and 1.9 folds of that from the 12% VA film, respectively. The antioxidant activity of the EVA films containing mangiferin and Span®20 was 80% radical-scavenging capacity (RSC for the 40 and 25% VA and 60% RSC for the 18 and 12% VA. The release of mangiferin from the EVA matrices may be controlled by appropriate selection of the surfactants and vinyl acetate contents.

Investigations on mechanical and two-body abrasive wear behaviour of glass/carbon fabric reinforced vinyl ester composites

International Nuclear Information System (INIS)

Suresha, B.; Kumar, Kunigal N. Shiva

2009-01-01

The aim of the research article is to study the mechanical and two-body abrasive wear behaviour of glass/carbon fabric reinforced vinyl ester composites. The measured wear volume loss increases with increase in abrading distance/abrasive particle size. However, the specific wear rate decreases with increase in abrading distance and decrease in abrasive particle size. The results showed that the highest specific wear rate is for glass fabric reinforced vinyl ester composite with a value of 10.89 x 10 -11 m 3 /Nm and the lowest wear rate is for carbon fabric reinforced vinyl ester composite with a value of 4.02 x 10 -11 m 3 /Nm. Mechanical properties were evaluated and obtained values are compared with the wear behaviour. The worn surface features have been examined using scanning electron microscope (SEM). Photomicrographs of the worn surfaces revealed higher percentage of broken glass fiber as compared to carbon fiber. Also better interfacial adhesion between carbon and vinyl ester in carbon reinforced vinyl ester composite was observed.

Vinyl ester resin and process for curing same with ionizing radiation in the presence of amines

International Nuclear Information System (INIS)

Mani, I.

1975-01-01

The addition of about 2 to 5 weight percent of certain amines to a thermosettable mixture of certain vinyl monomers and a polymerizable vinyl ester resin reduces the dosage level of ionizing radiation required to cure the mixture. (U.S.)

Vinyl flooring in the home is associated with children’s airborne butylbenzyl phthalate and urinary metabolite concentrations

Science.gov (United States)

Just, Allan C.; Miller, Rachel L.; Perzanowski, Matthew S.; Rundle, Andrew G.; Chen, Qixuan; Jung, Kyung Hwa; Hoepner, Lori; Camann, David E.; Calafat, Antonia M.; Perera, Frederica P.; Whyatt, Robin M.

2015-01-01

Prior studies have shown that vinyl flooring, as well as the vinyl-softening plasticizers butylbenzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP), are associated with asthma and airway inflammation. While DEHP exposure is primarily dietary, whether home vinyl flooring contributes to indoor air and urinary metabolite concentrations for these two phthalates is unclear. Exposures to BBzP and DEHP were examined in a prospective birth cohort of New York City children (n=239) using: (1) visual observation of potential phthalate containing flooring, (2) a two-week home indoor air sample, and (3) concurrent urinary metabolites in a subset (n=193). The category “vinyl or linoleum” flooring was observed in 135 (56%) of monitored rooms; these rooms had statistically significantly higher indoor air geometric mean concentrations of BBzP (23.9 ng/m3) than rooms with wood or carpet flooring (10.6 ng/m3). Children from homes with “vinyl or linoleum” flooring also had significantly higher urinary BBzP metabolite concentrations than other children. Indoor air BBzP and urinary metabolite concentrations were correlated positively (Spearman’s rho 0.40). By contrast, indoor air DEHP was not associated with flooring type nor with its urinary metabolite concentrations. Vinyl flooring in the home may be an important source of children’s exposure to BBzP via indoor air. PMID:25690585

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.

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 artifici...

21 CFR 177.1980 - Vinyl chloride-propylene copolymers.

Science.gov (United States)

2010-04-01

... used as components of articles intended for contact with food, subject to the provisions of this... chlorine content is in the range of 53 to 56 percent as determined by any suitable analytical procedure of... section. (d) Analytical methods: The analytical methods for determining whether vinyl chloride-propylene...

'Vinyl never say die': The re-incarnation, adoption and diffusion of retro-technologies

OpenAIRE

Sarpong, D.; Dong, S.; Appiah, G.

2016-01-01

New technologies continue to shape the way music is produced, distributed and consumed. The new turn to digital streaming services like iTunes, Spotify and Pandora, in particular, means that very recent music format technologies such as cassettes and CD's have almost lost their value. Surprisingly, one 'obsolete' music format technology, Vinyl record, is making a rapid comeback. Vinyl sales around the world, in recent times, have increased year on year, and the number of music enthusiast reac...

Methyltriphenylphosphonium Methylcarbonate, an All-In-One Wittig Vinylation Reagent.

Science.gov (United States)

Cattelan, Lisa; Noè, Marco; Selva, Maurizio; Demitri, Nicola; Perosa, Alvise

2015-12-07

The methyltriphenylphosphonium methylcarbonate salt [Ph3 PCH3 ][CH3 OCO2 ], obtained directly by quaternarization of triphenylphosphine with dimethylcarbonate, is a latent ylide that promotes Wittig vinylation of aldehydes and ketones. Alkenes are obtained simply by mixing [Ph3 PCH3 ][CH3 OCO2 ] and the carbonyl and heating in a solvent (no base, no halides, and no inorganic byproducts). Deuterium exchange experiments and the particularly short anion-cation distance measured by XRD in [Ph3 PCH3 ][CH3 OCO2 ] allowed to explain the nature and reactivity of this species. Green chemistry metrics (atom economy, mass index, environmental factor) indicate that this vinylation procedure is more efficient than comparable ones. Deuterated [Ph3 PCD3 ][CH3 OCO2 ] promoted the synthesis of deuterated olefins. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Investigation on the thermal properties of new thermo-reversible networks based on poly(vinyl furfural and multifunctional maleimide compounds

Directory of Open Access Journals (Sweden)

C. Gaina

2012-02-01

Full Text Available New thermo-reversible networks were obtained from poly(vinyl furfural and multifunctional maleimide monomers by Diels-Alder (DA and retro-DA reactions. The poly(vinyl furfural having acetalization degree of 15 and 25% were obtained by the acid-catalyzed homogenous acetalization of poly(vinyl alcohol with 2-furfural in a nonaqueous media. The thermal and viscoelastic behaviour of the cross-linked materials have been studied via differential scanning calorimetry, dynamic mechanical analysis and thermogravimetric analysis. The networks exhibit considerable swelling in those organic solvents that dissolve both poly(vinyl furfural and bismaleimides; by heating in aprotic dipolar solvents at 150°C, they become soluble.

75 FR 5578 - Submission for OMB Review; Comment Request-Flammability Standards for Clothing Textiles and Vinyl...

Science.gov (United States)

2010-02-03

... Standards for Clothing Textiles and Vinyl Plastic Film AGENCY: Consumer Product Safety Commission. ACTION: Notice. SUMMARY: Pursuant to the Paperwork Reduction Act of 1995 (44 U.S.C. Chapter 35), the Consumer... Commission's flammability standards for clothing textiles and vinyl plastic film. DATES: Written comments on...

Effect of organoelemental compounds of group 3 elements on radical polymerization of vinyl monomers

International Nuclear Information System (INIS)

Grishin, D.F.; Mojkin, A.A.

1996-01-01

When alkyl, alkyl alkoxy, and alkyl halide derivatives of boron and aluminium are introduced into the system in amounts that are comparable to the concentration of initiator, they coordinate to the growing macroradicals, thus changing their reactivity, and exert regulating effect on the rate of polymerization of vinyl monomers and the molecular mass of the resulting polymers. The said organoelemental compounds accelerate the polymerization of butyl acrylate, methyl methacrylate, acrylonitrile, vinyl acetate, and vinylidene chloride, reduce the molecular mass of acrylic polymers, and virtually do not affect the polymerization of styrene. The specific features of vinyl polymerization are associated with participation of organoelemental additives at the stages of chain growth and chain termination and can be explained within the framework of the mechanism of radical-coordination polymerization. 32 refs., 3 tabs

Chemical modification of poly(vinyl alcohol): evaluation of hydrophilic/lipophilic balance

International Nuclear Information System (INIS)

Aranha, Isabele B.; Lucas, Elizabete F.

2001-01-01

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 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)

Simple and fast polydimethylsiloxane (PDMS) patterning using a cutting plotter and vinyl adhesives to achieve etching results.

Science.gov (United States)

Hyun Kim; Sun-Young Yoo; Ji Sung Kim; Zihuan Wang; Woon Hee Lee; Kyo-In Koo; Jong-Mo Seo; Dong-Il Cho

2017-07-01

Inhibition of polydimethylsiloxane (PDMS) polymerization could be observed when spin-coated over vinyl substrates. The degree of polymerization, partially curing or fully curing, depended on the PDMS thickness coated over the vinyl substrate. This characteristic was exploited to achieve simple and fast PDMS patterning method using a vinyl adhesive layer patterned through a cutting plotter. The proposed patterning method showed results resembling PDMS etching. Therefore, patterning PDMS over PDMS, glass, silicon, and gold substrates were tested to compare the results with conventional etching methods. Vinyl stencils with widths ranging from 200μm to 1500μm were used for the procedure. To evaluate the accuracy of the cutting plotter, stencil designed on the AutoCAD software and the actual stencil widths were compared. Furthermore, this method's accuracy was also evaluated by comparing the widths of the actual stencils and etched PDMS results.

Biocatalytic Asymmetric Synthesis of (1R, 2S)-N-Boc-vinyl-ACCA Ethyl Ester with a Newly Isolated Sphingomonas aquatilis.

Science.gov (United States)

Zhu, Shaozhou; Shi, Ying; Zhang, Xinyu; Zheng, Guojun

2018-02-01

1-amino cyclopropane-1-carboxylic acid (ACCA) and its derivatives are essential pharmacophoric unit that widely used in drug research and development. Specifically, (1R, 2S)-N-Boc-vinyl-ACCA ethyl ester (vinyl-ACCA) is a key chiral intermediate in the synthesis of highly potent hepatitis C virus (HCV) NS3/4A protease inhibitors such as asunaprevir and simeprevir. Developing strategies for the asymmetric synthesis of vinyl-ACCA is thus extremely high demand. In this study, 378 bacterial strains were isolated from soil samples using N-Boc-vinyl-ACCA ethyl ester as the sole carbon source and were screened for esterase activity. Fourteen of which worked effectively for the asymmetric synthesis of (1R, 2S)-N-Boc-1-vinyl ACCA ethyl ester. The strain CY-2, identified as Sphingomonas aquatilis, which showed the highest stability and enantioselectivity was selected as whole cell biocatalyst for further study. A systematic study of all factors influencing the enzymatic hydrolysis was performed. Under optimized conditions, resolution of rac-vinyl-ACCA to (1R, 2S)-N-Boc-1-vinyl ACCA ethyl ester with 88.2% ee and 62.4% conversion (E = 9) was achieved. Besides, S. aquatilis was also used to transform other 10 different substrates. Notably, it was found that 7 of them could be stereoselectively hydrolyzed, especially for (1R,2S)-1-amino-vinyl-ACCA ethyl ester hydrochloride (99.6% ee, E>200). Our investigations provide a new efficient whole cell biocatalyst for resolution of ACCA and might be developed for industry application.

Radiation effect of ethylene/vinyl alcohol copolymer

International Nuclear Information System (INIS)

Liu Meihua; Jilin Univ., Changchun; Deng Pengyang; Sun Jiazhen; Dong Lisong; Sun Guoen; Zhang Wanxi

2006-01-01

The radiation effect of ethylene-vinyl alcohol copolymer (EVOH), EVOH/glycerin blend was studied by solvent extraction, gel permeation chromatography (GPC) and Fourier transform infrared spectrum (FTIR) methods. Samples were irradiated up to 1800 kGy at room temperature under N 2 . The results show that degradation is the main reaction in pure EVOH. Trace gel content could be found in E151 irradiated to at least 800 kGy, and only 5.9% gel content was found in the sample irradiated to 1200 kGy. While trace gel content could be found in F101 irradiated to at least 1800 kGy, the different gelation doses of E151 and F101 are due to different contents of vinyl alcohol units. Unsaturation structure can be found in the irradiated EVOH. The content increased at first, and then decreased, with the dose. The existence of double bond enhances the radiation efficiency of EVOH. For EVOH/glycerin blend, the gel content was higher than that of pure EVOH when the absorbed dose exceeds 800 kGy, and the gel content increased with the absorbed dose. But it cannot enhance radiation efficiency of EVOH as water. (authors)

Synthesis of vinyl phosphites

International Nuclear Information System (INIS)

Kabachnik, M.M.; Novikova, Z.S.; Neganova, E.G.; Lutsenko, I.F.

1986-01-01

The authors investigated the reactions of phosphoriodidites and phosphinous iodides with a number of aldehydes and ketones in presence of tertiary amines (triethylamine, pyridine, N,N-diethylaniline), and they have shown that as a result of the reactions the corresponding vinyl esters of phosphorus acids are formed. The reactions of phosphoriodidites (and phosphorodiamidous iodides) with aliphatic aldehydes (acetaldehyde, propionaldehyde, butyraldehyde, and isobutyraldehyde) go at a molar reactant ratio of 1:1 in either at room temperature and are practically complete in 5-6 h. The yields of the alkenyl phosphites (phosphorodiamidites) were 45-70%. The compositions and structures of the compounds obtained were confirmed by elemental analysis and the IR and 1 H and 31 P NMR spectra

How the Internet Facilitates the Activity within a Consumer Culture : - A Study of the Online Vinyl Record Network

OpenAIRE

Söderlindh, Stefan; Broman, David

2009-01-01

The purpose of this thesis is to describe and analyze how the online vinyl record network functions from both a consumer and retailer perspective, in order to gain an understanding of how the Internet facilitates the activity within a consumer culture. The vinyl record industry is experiencing a revival, with an upswing in sales and media attention and a significant increase in the amount of online trading. This inductive study contains data from qualitative interviews with ten vinyl record c...

Influence of substituents in vinyl groups on reactivity of parylene during polymerization process

International Nuclear Information System (INIS)

Freza, Sylwia; Skurski, Piotr; Bobrowski, Maciej

2010-01-01

The MCSCF calculations indicate that both triplet and singlet state of biradical di-para-xylylene can exist during polymerization of parylene in gas phase and both can potentially react with vinyl molecules. The singlet-state open-shell dimer turned out to exhibit multiconfigurational character. In the case of triplet state of the dimer two mechanisms of the reactions with various species containing vinyl groups have been examined at the B3LYP/6-31G level. The kinetic and thermodynamical barriers have been estimated for the reaction path involving the π-bond cleavage as well as for the route describing the hydrogen atom transfer. It was found that the overall reactions are thermodynamically favorable, whereas appropriate kinetic barriers for certain derivatives are very small (close to 0 kcal/mol) which in turn makes allowances for easy reactivity under accessible conditions. The calculated mechanisms indicate the influence of substituents in vinyl groups for reactivity of parylene during LPCVD process.

Strain Rate Dependent Ductile-to-Brittle Transition of Graphite Platelet Reinforced Vinyl Ester Nanocomposites

Directory of Open Access Journals (Sweden)

Brahmananda Pramanik

2014-01-01

Full Text Available In previous research, the fractal dimensions of fractured surfaces of vinyl ester based nanocomposites were estimated applying classical method on 3D digital microscopic images. The fracture energy and fracture toughness were obtained from fractal dimensions. A noteworthy observation, the strain rate dependent ductile-to-brittle transition of vinyl ester based nanocomposites, is reinvestigated in the current study. The candidate materials of xGnP (exfoliated graphite nanoplatelets reinforced and with additional CTBN (Carboxyl Terminated Butadiene Nitrile toughened vinyl ester based nanocomposites that are subjected to both quasi-static and high strain rate indirect tensile load using the traditional Brazilian test method. High-strain rate indirect tensile testing is performed with a modified Split-Hopkinson Pressure Bar (SHPB. Pristine vinyl ester shows ductile deformation under quasi-static loading and brittle failure when subjected to high-strain rate loading. This observation reconfirms the previous research findings on strain rate dependent ductile-to-brittle transition of this material system. Investigation of both quasi-static and dynamic indirect tensile test responses show the strain rate effect on the tensile strength and energy absorbing capacity of the candidate materials. Contribution of nanoreinforcement to the tensile properties is reported in this paper.

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

Fluorescent vinyl and styryl coumarins: A comprehensive DFT study ...

Indian Academy of Sciences (India)

Kiran Avhad

2017-11-14

Nov 14, 2017 ... Nonlinear optical properties of 3-styryl and 3-vinyl coumarin dyes have been investigated with ..... Figure 4. Dipole moment (μ in Debye) graph in the ground state (S0) and excited state (S1) in .... It gives information on shape,.

Robust Crosslinked Stereocomplexes and C60 Inclusion Complexes of Vinyl-Functionalized Stereoregular Polymers Derived from Chemo/Stereoselective Coordination Polymerization

KAUST Repository

Vidal, Fernando

2016-07-07

The successful synthesis of highly syndiotactic polar vinyl polymers bearing the reactive pendant vinyl group on each repeat unit, which is enabled by perfectly chemoselective and highly syndiospecific coordination polymerization of divinyl polar monomers developed through this work, has allowed the construction of robust crosslinked supramolecular stereocomplexes and C60 inclusion complexes. The metal-mediated coordination polymerization of three representative polar divinyl monomers, including vinyl methacrylate (VMA), allyl methacrylate (AMA), and N,N-diallyl acrylamide (DAA) by Cs-ligated zirconocenium ester enolate catalysts under ambient conditions exhibits complete chemoselectivity and high stereoselectivity, thus producing the corresponding vinyl-functionalized polymers with high (92% rr) to quantitative (>99% rr) syndiotacticity. A combined experimental (synthetic, kinetic, and mechanistic) and theoretical (DFT) investigation has yielded a unimetallic, enantiomorphic-site controlled propagation mechanism. Post-functionalization of the obtained syndiotactic vinyl-functionalized polymers via the thiol-ene click and photocuring reactions readily produced the corresponding thiolated polymers and flexible crosslinked thin film materials, respectively. Complexation of such syndiotactic vinyl-functionalized polymers with isotactic poly(methyl methacrylate) and fullerene C60 generates supramolecular crystalline helical stereocomplexes and inclusion complexes, respectively. Crosslinking of such complexes afforded robust crosslinked stereocomplexes that are solvent resistant and also exhibit considerably enhanced thermal and mechanical properties as compared to the uncrosslinked stereocompexes.

Robust Crosslinked Stereocomplexes and C60 Inclusion Complexes of Vinyl-Functionalized Stereoregular Polymers Derived from Chemo/Stereoselective Coordination Polymerization

KAUST Repository

Vidal, Fernando; Falivene, Laura; Caporaso, Lucia; Cavallo, Luigi; Chen, Eugene Y.-X.

2016-01-01

The successful synthesis of highly syndiotactic polar vinyl polymers bearing the reactive pendant vinyl group on each repeat unit, which is enabled by perfectly chemoselective and highly syndiospecific coordination polymerization of divinyl polar monomers developed through this work, has allowed the construction of robust crosslinked supramolecular stereocomplexes and C60 inclusion complexes. The metal-mediated coordination polymerization of three representative polar divinyl monomers, including vinyl methacrylate (VMA), allyl methacrylate (AMA), and N,N-diallyl acrylamide (DAA) by Cs-ligated zirconocenium ester enolate catalysts under ambient conditions exhibits complete chemoselectivity and high stereoselectivity, thus producing the corresponding vinyl-functionalized polymers with high (92% rr) to quantitative (>99% rr) syndiotacticity. A combined experimental (synthetic, kinetic, and mechanistic) and theoretical (DFT) investigation has yielded a unimetallic, enantiomorphic-site controlled propagation mechanism. Post-functionalization of the obtained syndiotactic vinyl-functionalized polymers via the thiol-ene click and photocuring reactions readily produced the corresponding thiolated polymers and flexible crosslinked thin film materials, respectively. Complexation of such syndiotactic vinyl-functionalized polymers with isotactic poly(methyl methacrylate) and fullerene C60 generates supramolecular crystalline helical stereocomplexes and inclusion complexes, respectively. Crosslinking of such complexes afforded robust crosslinked stereocomplexes that are solvent resistant and also exhibit considerably enhanced thermal and mechanical properties as compared to the uncrosslinked stereocompexes.

[3 + 2]-Cycloadditions of nitrile ylides after photoactivation of vinyl azides under flow conditions

Directory of Open Access Journals (Sweden)

Stephan Cludius-Brandt

2013-08-01

Full Text Available The photodenitrogenation of vinyl azides to 2H-azirines by using a photoflow reactor is reported and compared with thermal formation of 2H-azirines. Photochemically, the ring of the 2H-azirines was opened to yield the nitrile ylides, which underwent a [3 + 2]-cycloaddition with 1,3-dipolarophiles. When diisopropyl azodicarboxylate serves as the dipolarophile, 1,3,4-triazoles become directly accessible starting from the corresponding vinyl azide.

Hydrozirconation of lithium alkynylselenolate anions. Generation and reactions of alpha-zirconated vinyl selenide intermediates

Science.gov (United States)

Dabdoub; Begnini; Guerrero; Baroni

2000-01-14

Lithium alkynylselenolate anions react completely with 1.0 equiv of Cp(2)Zr(H)Cl in THF at room temperature to give exclusively the alpha-zirconated vinylselenolate intermediates 23-27, which by treatment with an alkyl halide afforded the alpha-zirconated vinyl alkylselenide intermediates 29-33. Reaction of 29-33 with butyltellurenyl bromide results in the formation of ketene telluro(seleno) acetals 35-39 with total control of the regio- and stereochemistry. The synthetic utility of the ketene telluro(seleno) acetals obtained here was demonstrated by reaction of 36 with butyllithium. This promotes the exclusive and stereospecific removal of the tellurium moiety and enables formation of the corresponding selenium-containing allylic alcohol of type 44, alpha-(alkylseleno)-alpha,beta-unsaturated aldehyde 45, ester 46, or carboxylic acid 47, after reaction with different types of electrophiles.

Effects of solvents on the radiation grafting reaction of vinyl compounds on poly (3-hydroxybutyrate)

International Nuclear Information System (INIS)

Torres, Maykel González; Talavera, José Rogelio Rodríguez; Muñoz, Susana Vargas; Pérez, Manuel González; Castro, Ma. Pilar. Carreón.; Cortes, Jorge Cerna

2015-01-01

Vinyl Acetate was grafted onto poly (3-hydroxybutyrate) by the simultaneous gamma irradiation method using different types of solvents and in bulk (solvent free), at 10 kGy and 1.62 kGy/h dose and dose rate respectively. Subsequent complete hydrolysis allowed the conversion of grafted chains from poly (vinyl acetate) to poly (vinyl alcohol). The aim of this study is to determine the effect of solvent through the estimation of the dependence of the degree of grafting with the choice of solvent, the calculation of the degree of crystallinity, and to study the biodegradation of the products. The results showed a greater degree of grafting in bulk, while the more suitable solvent was hexane. Characterization of the grafted copolymer indicated that crystallinity percentage decreased by an increase in grafting, while the biodegradability was promoted by the increment in poly (vinyl alcohol) grafted. - Highlights: • PHB was indirectly grafted with PVA, by complete hydrolysis of grafted PVAc. • The effect of solvents on the grafting, crystallinity and biodegradation was studied. • The characterizations of the products were obtained by SEM, TGA, and DSC

Preparation of poly(vinyl alcohol)/kaolinite nanocomposites via in situ polymerization

International Nuclear Information System (INIS)

Jia Xin; Li Yanfeng; Zhang Bo; Cheng Qiong; Zhang Shujiang

2008-01-01

Poly(vinyl alcohol)/kaolinite intercalated nanocomposites (Kao-PVA) were prepared via in situ intercalation radical polymerization. Vinyl acetate (VAc) was intercalated into kaolinite by a displacement method using dimethyl sulfoxide/kaolinite (Kao-DMSO) as the intermediate. Then, PVAc/kaolinite (Kao-PVAc) was obtained via radical polymerization with benzoyl peroxide (BPO) as initiator. Last, PVAc/kaolinite was saponified via direct-hydrolysis with NaOH solution in order to obtain PVA/kaolinite nanocomposites, which was characterized by Fourier-Transformation spectroscopy (FTIR), wide X-ray diffraction (WXRD) and transmission electron microscopy (TEM). Their differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) results of the obtained PVA/kaolinite suggested that the thermal properties had an obvious improvement

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).

Preparation of poly(vinyl alcohol)-grafted graphene oxide/poly(vinyl alcohol) nanocomposites via in-situ low-temperature emulsion polymerization and their thermal and mechanical characterization

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shengchang; Liu, Pengqing, E-mail: liupq@scu.edu.cn; Zhao, Xiangsen; Xu, Jianjun, E-mail: xujj@scu.edu.cn

2017-02-28

Highlights: • In-situ emulsion polymerization and alcoholysis reaction is a good method to prepare GO/PVA nanocomposites. • Surface chemical grafting modification of GO with PVA chains was also carried out during the in-situ emulsion polymerization and alcoholysis reaction. • The surface chemical grafting modification of GO by in-situ polymerization and alcoholysis reaction could not only improve the dispersion of fillers in matrix, but also the interfacial interactions between fillers and matrix. • The thermal and mechanical properties of PVA-g-GO/PVA nanocompistes were also studied. - Abstract: An in-situ polymerization combined with chemical grafting modification method for preparing Poly(vinyl alcohol)-grafted graphene oxide/Poly(vinyl alcohol) (PVA-g-GO/PVA) nanocomposites was reported. Firstly, Poly(vinyl acetate)-grafted graphene oxide/Poly(vinyl acetate) nanocomposites were prepared, and then the PVA-g-GO/PVA nanocomposites could be obtained through alcoholysis reaction. X-ray photoelectron spectrometer and fourier-transform infrared spectrometer confirmed that the PVAc or PVA chains were successfully grafted to GO sheets during in-situ polymerization and alcoholysis. And the results from transmission electron microscopy, scanning electron microscopy and X-ray diffraction showed that the well compatibility and homogenous dispersion of PVA-g-GO in PVA matrix could be achieved. Differential scanning calorimetric, thermogravimetry analysis and tensile test were employed to study the thermal and mechanical properties of the PVA-g-GO/PVA nanocomposites. The results indicated that a 53% improvement of tensile strength and a 36% improvement of Young’s modulus were achieved by addition of 0.5 wt% of GO sheets. And the glass transition temperature of PVA-g-GO/PVA nanocomposites was increased, and their thermal stability and crystallization degree were both decreased. Due to well dispersion of fillers and strong interfacial interactions at the filler

Preparation of poly(vinyl alcohol)-grafted graphene oxide/poly(vinyl alcohol) nanocomposites via in-situ low-temperature emulsion polymerization and their thermal and mechanical characterization

International Nuclear Information System (INIS)

Zhang, Shengchang; Liu, Pengqing; Zhao, Xiangsen; Xu, Jianjun

2017-01-01

Highlights: • In-situ emulsion polymerization and alcoholysis reaction is a good method to prepare GO/PVA nanocomposites. • Surface chemical grafting modification of GO with PVA chains was also carried out during the in-situ emulsion polymerization and alcoholysis reaction. • The surface chemical grafting modification of GO by in-situ polymerization and alcoholysis reaction could not only improve the dispersion of fillers in matrix, but also the interfacial interactions between fillers and matrix. • The thermal and mechanical properties of PVA-g-GO/PVA nanocompistes were also studied. - Abstract: An in-situ polymerization combined with chemical grafting modification method for preparing Poly(vinyl alcohol)-grafted graphene oxide/Poly(vinyl alcohol) (PVA-g-GO/PVA) nanocomposites was reported. Firstly, Poly(vinyl acetate)-grafted graphene oxide/Poly(vinyl acetate) nanocomposites were prepared, and then the PVA-g-GO/PVA nanocomposites could be obtained through alcoholysis reaction. X-ray photoelectron spectrometer and fourier-transform infrared spectrometer confirmed that the PVAc or PVA chains were successfully grafted to GO sheets during in-situ polymerization and alcoholysis. And the results from transmission electron microscopy, scanning electron microscopy and X-ray diffraction showed that the well compatibility and homogenous dispersion of PVA-g-GO in PVA matrix could be achieved. Differential scanning calorimetric, thermogravimetry analysis and tensile test were employed to study the thermal and mechanical properties of the PVA-g-GO/PVA nanocomposites. The results indicated that a 53% improvement of tensile strength and a 36% improvement of Young’s modulus were achieved by addition of 0.5 wt% of GO sheets. And the glass transition temperature of PVA-g-GO/PVA nanocomposites was increased, and their thermal stability and crystallization degree were both decreased. Due to well dispersion of fillers and strong interfacial interactions at the filler

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

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

Investigation Into Accessible Surface Vinyl Concentrations of Nonstoichiometric PDMS Microspheres from Hydrosilylation Reactions and Their Further Crosslinking Reactions

DEFF Research Database (Denmark)

Ma, Baoguang; Hansen, Jens Henrik; Hvilsted, Søren

2015-01-01

The introduction of surface vinyl groups to PDMS microspheres broadens the latter's applicability range since the microspheres can be further functionalized or crosslinked into elastomers. Quantification of the surface vinyl concentration of PDMS microspheres is therefore essential. Here, a novel...

An Investigation of Chitosan-Grafted-Poly(vinyl alcohol) as an Electrolyte Membrane

OpenAIRE

Panu Danwanichakul; Pongchayont Sirikhajornnam

2013-01-01

The membrane of chitosan-grafted-poly(vinyl alcohol)/poly(vinyl alcohol) (CS-g-PVA/PVA) was investigated along with chitosan (CS), PVA, CS/PVA, and Nafion 117 membranes for transport properties of water and methanol, mechanical properties, and ionic conductivity. The ionic conductivity, σ, of the crosslinked CS-g-PVA/PVA membrane was about 4.37 mS cm−1 and the methanol permeability, PS, was 1.8×10−7 cm2s−1. These gave the selectivity, σ/PS, of 23.95 mS·s·cm−3 compared with 16.35 mS·s·cm−3 of ...

The radiation-induced copolymerization of vinyl acetate with dibutyl maleate

International Nuclear Information System (INIS)

Du Plessis, T.A.; Lustig, A.

1975-01-01

The radiation-induced copolymerization of vinyl acetate with dibutyl maleate was investigated in the temperature range from -50 0 to 90 0 . A copolymer of the unsaturated ester with vinyl acetate was obtained in which the comonomers alternate with regularity along the polymer chain over the entire range of comonomer compositions and temperature range investigated. Both the rate of copolymerization and the molecular weight of the resulting copolymer were found to depend strongly on the comonomer composition. The monomer reactivity ratios were found to be practically zero. The apparent activation energy was found to change at 5 0 with an increase in temperature from a value of 1,6 kcal/mole to a value of 4,4kcal/mole. Scavenger studies indicate that a free radical mechanism prevails over the entire temperature range investigated. (Author) [af

Radiation grafting from binary monomer mixtures. II. Vinyl ether of monoethanolamine and N-vinylpyrrolidone

International Nuclear Information System (INIS)

Nurkeeva, Zauresh S.; Abdel Aal, A.-S.; Kupchishin, Anatoliy I.; Khutoryanskiy, Vitaliy V.; Mun, Grigoriy A.; Beksyrgaeva, Aida G.

2003-01-01

Radiation grafting from binary monomer mixtures of vinyl ether of monoethanolamine and N-vinylpyrrolidone onto polyethylene films has been studied. The structure of the grafted films was characterized by FTIR spectroscopy. Water uptake and contact angle measurements confirmed that the grafting leads to a considerable hydrophilization of the films surface. The presence of the more active N-vinylpyrrolidone enhances the grafting of the less active vinyl ether of monoethanolamine. Sorption properties of grafted films with respect to copper (II) ions have been studied

Radiation grafting from binary mixtures of vinyl ether of mono ethanol amine with N-vinylpyrrolidone and vinyl ether of ethylene glycol onto polyolefins films and metallization of obtained films

International Nuclear Information System (INIS)

Al'-Saed Abdel' Aal'; Nurkeeva, Z.; Khutoryanskij, V.; Mun, G.; Sangajlo, M.

2003-01-01

Radiation grafting from binary mixtures of vinyl ether of mono ethanol amine with N-vinylpyrrolidone and vinyl ether of ethylene glycol onto polyolefins films using γ-radiation and accelerated electrons has been studied. IR-spectroscopy is used to confirm the structure of grafted films. A combination of and metallization of obtained films. A combination of gravimetric and potentiometric techniques is applied to determine the fraction of each monomer in graft copolymer. Water uptake and contact angle measurements confirmed that the grafting process improve the hydrophilic properties of obtained films. The obtained materials are metallized by electroless copper plating. The metallized films have good electro conductive properties. (author)

Spectroscopic detection and mapping of vinyl cyanide on Titan

Science.gov (United States)

Cordiner, Martin; Yukiko Palmer, Maureen; Lai, James; Nixon, Conor A.; Teanby, Nicholas; Charnley, Steven B.; Vuitton, Veronique; Kisiel, Zbigniew; Irwin, Patrick; Molter, Ned; Mumma, Michael J.

2017-10-01

The first spectroscopic detection of vinyl cyanide (otherwise known as acrylonitrile; C2H3CN) on Titan was obtained by Palmer et al. (2017), based on three rotational emission lines observed with ALMA at millimeter wavelengths (in receiver band 6). The astrobiological significance of this detection was highlighted due to the theorized ability of C2H3CN molecules to combine into cell membrane-like structures under the cold conditions found in Titan's hydrocarbon lakes. Here we report the detection of three additional C2H3CN transitions at higher frequencies (from ALMA band 7 flux calibration data). We present the first emission maps for this gas on Titan, and compare the molecular distribution with that of other nitriles observed with ALMA including HC3N, CH3CN, C2H5CN and HNC. The molecular abundance patterns are interpreted based on our understanding of Titan's high-altitude photochemistry and time-variable global circulation. Similar to the short-lived HC3N molecule, vinyl cyanide is found to be most abundant in the vicinity of the southern (winter) pole, whereas the longer-lived CH3CN is more concentrated in the north. The vertical abundance profile of C2H3CN (from radiative transfer modeling), as well as its latitudinal distribution, are consistent with a short photochemical lifetime for this species. Complementary results from our more recent (2017) nitrile mapping studies at higher spatial resolution will also be discussed.REFERENCES:Palmer, M. Y., Cordiner, M. A., Nixon, C. A. et al. "ALMA detection and astrobiological potential of vinyl cyanide on Titan", Sci. Adv. 2017, 3, e1700022

New examples of the vinylation of NH-heterocycles with acetylene at atmospheric pressure in the KOH-DMSO system

Energy Technology Data Exchange (ETDEWEB)

Trofimov, B.A.; Nesterenko, R.N.; Mikhaleva, A.I.; Shapiro, A.B.; Aliev, I.A.; Yakovleva, I.V.; Kalabin, G.A.

1986-10-01

Vinylation of 2-hetarylpyrroles, 4,5-dihydrobenzo(g)indole, and 1,2,3,4-tetrahydro-..gamma..-carbinols at atmospheric pressure in the superbasic system KOH-DMSO at 100-120/sup 0/C has given the corresponding N-vinyl derivatives in yields of 92-99%.

Phytoscreening for vinyl chloride in groundwater discharging to a stream

DEFF Research Database (Denmark)

Ottosen, Cecilie Bang; Rønde, Vinni Kampman; Trapp, Stefan

2018-01-01

and hence different uptake/loss scenarios. Vinyl chloride (VC) as well as cis-dichloroethylene (cis-DCE), trichloroethylene (TCE), and tetrachloroethylene (PCE) were detected in the trees, documenting that phytoscreening is a viable method to locate chlorinated ethene plumes, including VC, discharging...

40 CFR 61.63 - Emission standard for vinyl chloride plants.

Science.gov (United States)

2010-07-01

... plants. 61.63 Section 61.63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard... formation and purification: The concentration of vinyl chloride in each exhaust gas stream from any...

Using the Maturity Method in Predicting the Compressive Strength of Vinyl Ester Polymer Concrete at an Early Age

Directory of Open Access Journals (Sweden)

Nan Ji Jin

2017-01-01

Full Text Available The compressive strength of vinyl ester polymer concrete is predicted using the maturity method. The compressive strength rapidly increased until the curing age of 24 hrs and thereafter slowly increased until the curing age of 72 hrs. As the MMA content increased, the compressive strength decreased. Furthermore, as the curing temperature decreased, compressive strength decreased. For vinyl ester polymer concrete, datum temperature, ranging from −22.5 to −24.6°C, decreased as the MMA content increased. The maturity index equation for cement concrete cannot be applied to polymer concrete and the maturity of vinyl ester polymer concrete can only be estimated through control of the time interval Δt. Thus, this study introduced a suitable scaled-down factor (n for the determination of polymer concrete’s maturity, and a factor of 0.3 was the most suitable. Also, the DR-HILL compressive strength prediction model was determined as applicable to vinyl ester polymer concrete among the dose-response models. For the parameters of the prediction model, applying the parameters by combining all data obtained from the three different amounts of MMA content was deemed acceptable. The study results could be useful for the quality control of vinyl ester polymer concrete and nondestructive prediction of early age strength.

Synthesis of alkynes from vinyl triflates using tetrabutylammonium fluoride.

Science.gov (United States)

Okutani, Masaru; Mori, Yuji

2015-01-01

A convenient method for the preparation of alkynes and alkynyl esters from ketones and β-keto esters is described which involves the formation of vinyl triflates, followed by elimination with tetrabutylammonium fluoride trihydrate, to give alkynes. Unlike established elimination methods, the method requires neither a strong base nor anhydrous conditions.

Reactive compatibilization of ethylene-co-vinyl acetate/starch blends

NARCIS (Netherlands)

Ma, P.; Hristova - Bogaerds, D.G.; Schmit, P.; Goossens, J.G.P.; Lemstra, P.J.

2012-01-01

The dispersion of starch as a filler in hydrophobic ethylene-co-vinyl acetate (EVA) rubber is an issue. To obtain a fine dispersion of starch in EVA rubber, EVA/starch blends were prepared by reactive extrusion in the pres- ence of maleic anhydride (MA), benzoyl peroxide (BPO), and glycerol. MA,

Comparison of slime-producing coagulase-negative Staphylococcus colonization rates on vinyl and ceramic tile flooring materials.

Science.gov (United States)

Yazgi, H; Uyanik, M H; Ayyildiz, A

2009-01-01

This study investigated the colonization of slime-producing coagulase-negative Staphylococcus (CoNS) in 80 patient wards in Turkey (40 vinyl and 40 ceramic tile floors). A total of 480 samples that included 557 CoNS isolates were obtained. Slime production was investigated with the Christensen method and methicillin-susceptibility was tested by the disk-diffusion method. There was a significant difference in the percentage of slime-producing CoNS isolates on vinyl (12.4%) versus ceramic tile flooring (4.4%). From vinyl flooring, the percentage of slime producing methicillin-resistant CoNS (MRCoNS) (8.9%) was significantly higher than for methicillin-sensitive CoNS (MSCoNS) (3.6%), whereas there was no difference from ceramic tile flooring (2.5% MRCoNS versus 1.8% MSCoNS). The most commonly isolated slime-producing CoNS species was S. epidermidis on both types of flooring. It is concluded that vinyl flooring seems to be a more suitable colonization surface for slime-producing CoNS than ceramic tile floors. Further studies are needed to investigate bacterial strains colonized on flooring materials, which are potential pathogens for nosocomial infections.

Vinyl Monomers Double as UV Stabilizers: 179th ACS Meeting Houston.

Science.gov (United States)

Chemical and Engineering News, 1980

1980-01-01

Synthesis and polymerization of vinyl monomers that double as stabilizers against degradation of plastics by ultraviolet light has been accomplished. Potential applications include protection of photovoltaic cells in solar power plants. (Author/RE)

Far-infrared Spectroscopic Characterization of Anti-vinyl Alcohol

Science.gov (United States)

Bunn, Hayley; Soliday, Rebekah M.; Sumner, Isaiah; Raston, Paul L.

2017-09-01

We report a detailed analysis of the high-resolution far-infrared spectrum of anti-vinyl alcohol, which has been previously identified toward Sagittarius B2(N). The ν 15 OH torsional fundamental investigated here is more than 200 cm-1 removed from the next nearest vibration, making it practically unperturbed and ideal to help refine the ground state rotational constants that were previously determined from 25 microwave lines. We assigned 1335 lines within the ν 15 fundamental centered at 261.5512 cm-1, with J and K a ranges of 1-59 and 0-16, respectively. The microwave and far-infrared line positions were fit with Watson-type A- and S-reduced Hamiltonians, with the inclusion of quartic and select sextic distortion terms. This resulted in a significant refinement of the ground state constants, in addition to the determination of the {ν }15=1 state constants for the first time. The spectroscopic parameters are in good agreement with the results from anharmonic coupled-cluster calculations, and should be useful in searches for rotationally and/or vibrationally warm anti-vinyl alcohol in interstellar molecular clouds.

Reduction of CT beam hardening artefacts of ethylene vinyl alcohol copolymer by variation of the tantalum content: evaluation in a standardized aortic endoleak phantom

International Nuclear Information System (INIS)

Treitl, Karla M.; Scherr, Michael; Foerth, Monika; Braun, Franziska; Maxien, Daniel; Treitl, Marcus

2015-01-01

Our aim was to develop an aortic stent graft phantom to simulate endoleak treatment and to find a tantalum content (TC) of ethylene-vinyl-alcohol-copolymer that causes fewer computed tomography (CT) beam hardening artefacts, but still allows for fluoroscopic visualization. Ethylene-vinyl-alcohol-copolymer specimens of different TC (10-50 %, and 100 %) were injected in an aortic phantom bearing a stent graft and endoleak cavities with simulated re-perfusion. Fluoroscopic visibility of the ethylene-vinyl-alcohol-copolymer specimens was analyzed. In addition, six radiologists analyzed endoleak visibility, and artefact intensity of ethylene-vinyl-alcohol-copolymer in CT. Reduction of TC significantly decreased CT artefact intensity of ethylene-vinyl-alcohol-copolymer and increased visibility of endoleak re-perfusion (p < 0.000). It also significantly decreased fluoroscopic visibility of ethylene-vinyl-alcohol-copolymer (R = 0.883, p ≤ 0.01), and increased the active embolic volumes prior to visualization (Δ ≥ 40 μl). Ethylene-vinyl-alcohol-copolymer specimens with a TC of 45-50 % exhibited reasonable visibility, a low active embolic volume and a tolerable CT artefact intensity. The developed aortic stent graft phantom allows for a reproducible simulation of embolization of endoleaks. The data suggest a reduction of the TC of ethylene-vinyl-alcohol-copolymer to 45 -50 % of the original, to interfere less with diagnostic imaging in follow-up CT examinations, while still allowing for fluoroscopic visualization. (orig.)

Zinc(II) catalyzed conversion of alkynes to vinyl triflates in the presence of silyl triflates.

Science.gov (United States)

Al-huniti, Mohammed H; Lepore, Salvatore D

2014-08-15

The conversion of alkynes to their corresponding vinyl triflates in the presence of stoichiometric TMS-triflate was greatly facilitated by the triflate salt of several transition metal catalysts most especially Zn(OTf)2. Products are formed in high regioselectivity under mild conditions. Internal alkynes bearing an aryl substituent afford vinyl triflates with a modest preference for the Z-isomer especially with larger substituents. A mechanism is put forward to explain the unique role of silicon in this system.

Synthesis of Ethylene or Propylene/1,3-Butadiene Copolymers Possessing Pendant Vinyl Groups with Virtually No Internal Olefins

Directory of Open Access Journals (Sweden)

Kenji Michiue

2015-11-01

Full Text Available In general, ethylene/1,3-butadiene copolymerizations provides copolymers possessing both pendant vinyls and vinylenes as olefinic moieties. We, at MCI, studied the substituent effects of C2-symmetric zirconocene complexes, rac-[Me2Si(Indenyl’2]ZrCl2 (Indenyl’ = generic substituted indenyl, after activation on the ratio of the pendant vinyls and vinylenes of the resultant copolymers. Complexes examined in this study were rac-dimethylsilylbis (1-indenylzirconium dichloride (1, rac-dimethylsilyl-bis[1-(2-methyl-4,5-benzoindenyl] zirconium dichloride (2, rac-dimethylsilyl-bis[l-(2-methyl -4-phenylindenyl]zirconium dichloride (3, rac-dimethy1si1y1- bis(2-ethyl-4-phenylindenyl zirconium dichloride (4, rac-dimethylsilyl-bis[l-(2-n-propyl -4-(1-naphthylindenyl]zirconium dichloride (5, rac-dimethylsilyl-[1-(2-ethyl-4-(5-(2,2-dimethyl-2,3-dihydro-1H-cyclopenta [a]naphthalenylindenyl][1-(2-n-propyl-4-(5-(2,2-dimethyl-2,3-dihydro-1H-cyclopenta[a] naphthalenylindenyl]zirconium dichloride (6, rac-dimethylsilyl-bis[1-(2-ethyl-4-(9-phenanthrylindenyl]zirconium dichloride (7, and rac-dimethylsilyl-bis[l-(2-n-propyl-4-(9-phenanthrylindenyl]zirconium dichloride (8. We found that the ratio of the pendant vinyls and vinylenes is strongly affected by the bulkiness of the substituent on the complexes examined. The vinyl content increased linearly in the following order, 8 > 7 > 6 > 5 > 4 > 3 > 2 > 1. Notably, complex 8/DMAO formed ethylene/1,3-butadiene copolymers possessing predominant vinyl groups, which can be crucial precursors for functionalized polyolefins. Likewise, complex 8/DMAO afforded propylene/1,3-butadiene copolymers with predominant vinyl groups.

Characterization of nanocellulose reinforced semi-interpenetrating polymer network of poly(vinyl alcohol) & polyacrylamide composite films.

Science.gov (United States)

Mandal, Arup; Chakrabarty, Debabrata

2015-12-10

Semi-interpenetrating polymer network (semi-IPN) of poly(vinyl alcohol)/polyacrylamide was reinforced with various doses of nanocellulose. The different composite films thus prepared were characterized with respect to their mechanical, thermal, morphological and barrier properties. The composite film containing 5 wt.% of nanocellulose showed the highest tensile strength. The semi-interpenetrating polymer network of poly(vinyl alcohol)/polyacrylamide; and its various composites with nanocellulose were almost identical in their thermal stability. Each of the composites however exhibited much superior stability with respect to the linear poly(vinyl alcohol) and crosslinked polyacrylamide. The scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies exhibited phase separated morphology where agglomerates of nanocellulose were found to be dispersed in the matrix of the semi-IPN. The moisture vapor transmission rate (MVTR) was the lowest for the film containing 5 wt.% of nanocellulose. Copyright © 2015 Elsevier Ltd. All rights reserved.

Poly(aniline-co-m-aminobenzoic acid) deposited on poly(vinyl ...

Indian Academy of Sciences (India)

Abstract. In this work, we have deposited poly(aniline-co-m-aminobenzoic acid) on poly(vinyl alcohol) (PVA) by in situ ... along the polyaniline (PANI) chain results in self dop- ing of PANI and ..... The value of electrical conductivity is found to be ...

1,4-Di(2-butoxycarbonyl-trans-vinyl-2,5-dimethoxybenzene

Directory of Open Access Journals (Sweden)

William A. Molano

2015-11-01

Full Text Available The title compound 1,4-di(2-butoxycarbonyl-trans-vinyl-2,5-dimethoxybenzene was synthesized in 94% yield through the Heck reaction between 2,5-diiodo-1,4-dimethoxybenzene and n-butyl acrylate, using bis(dibenzylideneacetone palladium(0 as homogeneous catalyst.

Cross-Coupling of Sodium Sulfinates with Aryl, Heteroaryl and Vinyl Halides by Nickel/photoredox dual catalysis

KAUST Repository

Yue, Huifeng

2017-12-06

An efficient photoredox/nickel dual catalyzed sulfonylation reaction of aryl, heteroaryl, and vinyl halides has been achieved for the first time. This newly developed sulfonylation protocol provides a versatile method for the synthesis of diverse aromatic sulfones at room temperature and shows excellent functional group tolerance. The electrophilic coupling partners are not limited to aryl, heteroaryl and vinyl bromides but also less reactive aryl chlorides are suitable substrates for this transformation.

Cross-Coupling of Sodium Sulfinates with Aryl, Heteroaryl and Vinyl Halides by Nickel/photoredox dual catalysis

KAUST Repository

Yue, Huifeng; Zhu, Chen; Rueping, Magnus

2017-01-01

An efficient photoredox/nickel dual catalyzed sulfonylation reaction of aryl, heteroaryl, and vinyl halides has been achieved for the first time. This newly developed sulfonylation protocol provides a versatile method for the synthesis of diverse aromatic sulfones at room temperature and shows excellent functional group tolerance. The electrophilic coupling partners are not limited to aryl, heteroaryl and vinyl bromides but also less reactive aryl chlorides are suitable substrates for this transformation.

Vinyl Chloride Emulsion Polymerization Reaction: Effect of Various Formulations

Directory of Open Access Journals (Sweden)

Seyed Mehrdad Jalilian

2013-01-01

Full Text Available A mixture  of  sodium  lauryl  sulfate  (SLS  as  ionic  emulsifer  and  stearyl alcohol as non-ionic emulsifer was employed in a vinyl chloride emulsion polymerization  reaction  to  study  the  infuence  of  various  interactive parameters involved in the reaction system. It was found that the particle size was dependent on the amount and type of emulsifer. The average particle size of polyvinyl chloride was dropped by higher amount of emulsifying agents.  At the gel point, more heat was generated by higher amount of vinyl chloride fed into the reaction system. The molecular weight of the polymer was decreased by increases in reaction temperature while,  it  increased by augmenting  the amount of emulsifer. According to the 13C NMR and FTIR spectroscopic data no defect was detected in the chain structure of synthetic polyvinylchloride product. An optimization of polymerization reaction condition was reached based on ultimate particle size desired for its favorable distribution in plastisols.

Analysis on the Utility of Satellite Imagery for Detection of Agricultural Facility

Science.gov (United States)

Kang, J.-M.; Baek, S.-H.; Jung, K.-Y.

2012-07-01

Now that the agricultural facilities are being increase owing to development of technology and diversification of agriculture and the ratio of garden crops that are imported a lot and the crops cultivated in facilities are raised in Korea, the number of vinyl greenhouses is tending upward. So, it is important to grasp the distribution of vinyl greenhouses as much as that of rice fields, dry fields and orchards, but it is difficult to collect the information of wide areas economically and correctly. Remote sensing using satellite imagery is able to obtain data of wide area at the same time, quickly and cost-effectively collect, monitor and analyze information from every object on earth. In this study, in order to analyze the utilization of satellite imagery at detection of agricultural facility, image classification was performed about the agricultural facility, vinyl greenhouse using Formosat-2 satellite imagery. The training set of sea, vegetation, building, bare ground and vinyl greenhouse was set to monitor the agricultural facilities of the object area and the training set for the vinyl greenhouses that are main monitoring object was classified and set again into 3 types according the spectral characteristics. The image classification using 4 kinds of supervise classification methods applied by the same training set were carried out to grasp the image classification method which is effective for monitoring agricultural facilities. And, in order to minimize the misclassification appeared in the classification using the spectral information, the accuracy of classification was intended to be raised by adding texture information. The results of classification were analyzed regarding the accuracy comparing with that of naked-eyed detection. As the results of classification, the method of Mahalanobis distance was shown as more efficient than other methods and the accuracy of classification was higher when adding texture information. Hence the more effective

ANALYSIS ON THE UTILITY OF SATELLITE IMAGERY FOR DETECTION OF AGRICULTURAL FACILITY

Directory of Open Access Journals (Sweden)

J.-M. Kang

2012-07-01

Full Text Available Now that the agricultural facilities are being increase owing to development of technology and diversification of agriculture and the ratio of garden crops that are imported a lot and the crops cultivated in facilities are raised in Korea, the number of vinyl greenhouses is tending upward. So, it is important to grasp the distribution of vinyl greenhouses as much as that of rice fields, dry fields and orchards, but it is difficult to collect the information of wide areas economically and correctly. Remote sensing using satellite imagery is able to obtain data of wide area at the same time, quickly and cost-effectively collect, monitor and analyze information from every object on earth. In this study, in order to analyze the utilization of satellite imagery at detection of agricultural facility, image classification was performed about the agricultural facility, vinyl greenhouse using Formosat-2 satellite imagery. The training set of sea, vegetation, building, bare ground and vinyl greenhouse was set to monitor the agricultural facilities of the object area and the training set for the vinyl greenhouses that are main monitoring object was classified and set again into 3 types according the spectral characteristics. The image classification using 4 kinds of supervise classification methods applied by the same training set were carried out to grasp the image classification method which is effective for monitoring agricultural facilities. And, in order to minimize the misclassification appeared in the classification using the spectral information, the accuracy of classification was intended to be raised by adding texture information. The results of classification were analyzed regarding the accuracy comparing with that of naked-eyed detection. As the results of classification, the method of Mahalanobis distance was shown as more efficient than other methods and the accuracy of classification was higher when adding texture information. Hence the more

Pemanfaatan limbah kopolimer ethyene vinyl acetateuntuk komposit karet

Directory of Open Access Journals (Sweden)

Dwi Wahini Nurhajati

2008-12-01

Full Text Available A new composite of natural rubber blend with ethylene vinyl acetate (EVA waste obtained from footwear industry hase been made. EVA waste from footwear industry is crosslinked materials which is able to be used as a filler in composite rubber. Potency of EVA waste in the form of powder from the footwear industry in Indonesia is more than 50kg/day, while in the form of solid is about 75,000 ton/ year and is hasn’t yet utilized. The aim of this research is to study influence of EVA waste on the physical properties of natural rubber composite filled with EVA waste. Natural rubber, EVA waste, and addives were mixed by a two-roll mills machine. The amounts of EVA waste were varied from 0 to 100 phr with range of 20 phr. The results of physical properties test showed that the maximum addition of EVA waste, which performed highest tensile strength, and tear resistance was found for 60 phr, and which contributed to an increase in higher elongation at break, hardness, 50% permanent set, and density was found for 100 phr. The addition of EVA waste resulted in a reduction of the abrasion resistance. All of the resulted composites there were no crack detected on the flex cracking test at 150 kcs.

Polysulfone hemodiafiltration membranes with enhanced anti-fouling and hemocompatibility modified by poly(vinyl pyrrolidone) via in situ cross-linked polymerization.

Science.gov (United States)

Zhu, Lijing; Song, Haiming; Wang, Jiarong; Xue, Lixin

2017-05-01

Poly(vinyl pyrrolidone) (PVP) and its copolymers have been widely employed for the modification of hemodiafiltration membranes due to their excellent hydrophilicity, antifouling and hemocompatibility. However, challenges still remain to simplify the modification procedure and to improve the utilization efficiency. In this paper, antifouling and hemocompatibility polysulfone (PSf) hemodiafiltration membranes were fabricated via in situ cross-linked polymerization of vinyl pyrrolidone (VP) and vinyltriethoxysilane (VTEOS) in PSf solutions and non-solvent induced phase separation (NIPS) technique. The prepared membranes were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), which suggested that VP and VTEOS have been cross-linked copolymerized in PSf membranes. The modified PSf membranes with high polymer content showed improved hydrophilicity, ultrafiltration and protein antifouling ability. In addition, the modified PSf membranes showed lower protein adsorption, inhibited platelet adhesion and deformation, prolonged the activated partial thromboplastin time (APTT), prothrombin time (PT), and decreased the content of fibrinogen (FIB) transferring to fibrin, indicating enhanced hemocompatibility. In a word, the present work provides a simple and effective one-step modification method to construct PSf membranes with improved hydrophilicity, antifouling and hemocompatibility. Copyright © 2017 Elsevier B.V. All rights reserved.

Pyrolysis-gas chromatography-mass spectrometry for studying N-vinyl-2-pyrrolidone-co-vinyl acetate copolymers and their dissolution behaviour.

Science.gov (United States)

Chojnacka, Aleksandra; Ghaffar, Abdul; Feilden, Andrew; Treacher, Kevin; Janssen, Hans-Gerd; Schoenmakers, Peter

2011-11-14

Knowledge on the solubility behaviour and dissolution rate of speciality and commodity polymers is very important for the use of such materials in high-tech applications. We have developed methods for the quantification and characterization of dissolved copolymers of N-vinyl-2-pyrrolidone (VP) and vinyl acetate (VA) during dissolution in water. The methods are based on pyrolysis (Py) performed in a programmed-temperature vaporization injector with subsequent identification and quantification of the components in the pyrolysate using capillary gas chromatography-mass spectrometry (GC-MS). By injecting large volumes and applying cryo-focussing at the top of the column, low detection limits could be achieved. The monomer ratio was found to have the greatest effect on the dissolution rate of the PVP-co-VA copolymers. The material with the highest amount of VA (50%) dissolves significantly slower than the other grades. Size-exclusion chromatography (SEC) and Py-GC-MS were used to measure molecular weights and average chemical compositions, respectively. Combined off-line SEC//Py-GC-MS was used to determine the copolymer composition (VP/VA ratio), as a function of the molecular weight for the pure polymers. In the dissolution experiments, a constant VP/VA ratio across the dissolution curve was observed for all copolymers analysed. This suggests a random distribution of the two monomers over the molecules. Copyright © 2011 Elsevier B.V. All rights reserved.

Preparation of CuS nanoparticles embedded in poly(vinyl alcohol ...

Indian Academy of Sciences (India)

WINTEC

ray diffraction (XRD) analyses and electron diffraction pattern also revealed the forming of CuS crystal structure in the PVA fibres. Keywords. CuS nanoparticles; electrospinning; poly(vinyl alcohol). 1. Introduction. In the past decade, the preparation of low-dimensional semiconductor nanostructures has become a hotspot of.

Complex-radical copolymerization of vinyl monomers on organoelemental initiators

International Nuclear Information System (INIS)

Grishin, D.F.

1993-01-01

Data on regularities of the initiation and growth of the (co)polymerization of polar vinyl series monomers on organo-elemental initiator, organo-boron in particular, are generalized. The effect of organo-metallic compounds and some phenol type inhibitors on the rate of acrylate (co)polymerization is analyzed from view of the change of electroacceptor properties (electrophilicity) of macroradicals

Effect of Compatibilization on Poly-ε-Caprolactone Grafting onto Poly(ethylene-co-vinyl alcohol

Directory of Open Access Journals (Sweden)

Mohamed Taha

2011-10-01

Full Text Available The non-miscibility of the reactants during solvent free poly-ε-caprolactone grafting onto poly(ethylene-co-vinyl alcohol (EVOH dramatically affects reaction kinetics. Different solutions were proposed to accelerate the exchange reactions between poly(ethylene-co-vinyl alcohol and poly-ε-caprolactone. Reactions were conducted in a batch reactor or a mini twin-screw extruder. The addition of a poly(ethylene-co-vinyl alcohol-g-poly-ε-caprolactone copolymer increased the compatibility of the reactants and led to a higher reaction rate. This copolymer was either prepared separately and added at the reaction beginning or prepared in situ grafting caprolactone from EVOH. The reactive system evolution was analyzed using molar mass evolution, microstructure characterization, thermal properties and the reactive blend morphology. The compatibilization effect combined with optimized reaction conditions, such as concentration and nature of catalyst and temperature, resulted in an important increase in reaction rates. Among the tested catalysts, 1,5,7-Triazabicyclo [4.4.0]dec-5-ene was a more efficient catalyst for grafting reactions than Tin (II 2-ethylhexanoate.

ANALYSIS OF ADIPATE ESTER CONTENTS IN POLY(VINYL CHLORIDE) PLASTICS

DEFF Research Database (Denmark)

Berg, Rolf W.; Otero, Amalia Dopazo

2006-01-01

Fourier transform (FT-) Raman spectroscopy excited with a 1064 nm laser can be used to determine the content of plasticizers in commercial flexible poly vinyl chloride (PVC) products. Our previous study [T. Nørbygaard, R.W. Berg, Analysis of phthalate ester content in PVC plastics by means of FT......-Raman Spectroscopy, Appl. Spectrosc. 58 (4) (2004) 410–413]—on detection of the presence of phthalate esters in PVC by FT-Raman spectroscopy — is here extended to the similar case of adipate esters (AEs) in samples of soft poly vinyl chloride plastics. Spectra of a range of adipate ester plasticizers (11 AEs......) in pure form are reported. We studied if qualitative and quantitative determination of the adipate ester content would be possible based on the use of proper reference samples. It was found that AEs as a group cannot be definitively identified by their characteristic Raman bands because other aliphatic...

Oil recovery with vinyl sulfonic acid-acrylamide copolymers

Energy Technology Data Exchange (ETDEWEB)

Norton, C.J.; Falk, D.O.

1973-12-18

An aqueous polymer flood containing sulfomethylated alkali metal vinyl sulfonate-acrylamide copolymers was proposed for use in secondary or tertiary enhanced oil recovery. The sulfonate groups on the copolymers sustain the viscosity of the flood in the presence of brine and lime. Injection of the copolymer solution into a waterflooded Berea core, produced 30.5 percent of the residual oil. It is preferred that the copolymers are partially hydrolyzed.

Properties of poly(vinyl alcohol)–borax gel doped with neodymium ...

Indian Academy of Sciences (India)

visible region then leads to luminescent emission in the near infra-red region. The spectral qualities of the ... molecular hydrogen bonding between the hydroxyl groups on poly(vinyl ..... mately results in near IR emissions. The maximum of the.

Radiation cross-linking of ethylene vinyl alcohol copolymer functionalized with m-isopropenyl-α,α-dimethyl benzyl isocyanate

International Nuclear Information System (INIS)

Ekman, K.B.; Naesman, J.H.

1993-01-01

An ethylene vinyl alcohol copolymer was functionalized with m-isopropenyl-α,α-dimethyl benzyl isocyanate using reactive processing in a mixer. The functionalization introduces pendant unsaturation to the polymer, which allows radiation cross-linked to gel contents >70% at radiation doses below 100 kGy. Unfunctionalized ethylene vinyl alcohol copolymer, on the other hand, forms no gel upon irradiation. The functionalization was completed within a few minutes of reactive mixing, which was confirmed with both FTIR and 13 C-NMR measurements. The oxygen permeability of ethylene vinyl alcohol copolymer increased with increasing degree of functionalization, and irradiation of the samples formed trapped radicals, which act as oxygen scavengers. Consequently no oxygen permeability was detected. However, radical activity was inhibited by annealing the samples at 110 C resulting in a 24% higher oxygen permeability value for the irradiated unfunctionalized copolymer. The oxygen permeability values of the irradiated functionalized samples were approximately 13% lower. Laminates of m-isopropenyl-α,α-dimethyl benzyl isocyanate functionalized ethylene vinyl alcohol copolymer and m-isopropenyl-α,α-dimethyl benzyl isocyanate functionalized ethylene hydroxyethyl methacrylate copolymer acquired improved adhesive strength both at dry and wet conditions as well as at elevated temperature upon exposure to radiation

Small Angle Neutron Scattering Studies on Blends of Poly (Styrene-ran-Vinyl Phenol) with Liquid Crystalline Polyurethane

Science.gov (United States)

Mehta, Rujul

2005-03-01

Molecular composites, composed of uniformly dispersed rigid-rod liquid crystalline polymer (LCP) molecules in a flexible amorphous polymer matrix, have remained hitherto elusive due to a scarcity of miscible systems containing a LCP and an amorphous polymer. The production of such a blend, with an experimentally accessible miscibility window, has become possible by modifying the architecture of the flexible polymer, so as to induce favorable intermolecular hydrogen bonding. Specifically, liquid crystalline polyurethanes (LCPU) are found to be miscible with a copolymer of styrene and vinyl phenol; with optimum hydrogen bonding between the carbonyl groups of the urethane linkages and the hydroxyl groups present in the styrenic matrix. Availability of a truly miscible molecular composite presents a unique opportunity of studying the confirmation of polymer chains containing rigid-rods that are uniformly dispersed in a flexible coil matrix. A system consisting of the LCPU and the deuterated styrenic copolymer containing 20% vinyl phenol is examined by Small Angle Neutron Scattering at the National Center for Neutron Research at Gaithersburg and Technology, and the Institute of Solid State Research (IFF) at Jülich. Scattering curves for neat dPS-VPh did not fit the Debye-Bueche model; indicating complex structure. A two correlation length Debye-Bueche model was considered to accommodate for this nonlinear behavior. This model utilizes four fitting parameters, including two correlation lengths a1 and a2, corresponding to a Debye-Bueche model and Guinier model.

Biotransformation of ferulic acid to 4-vinyl guaiacol by Lactobacillus ...

African Journals Online (AJOL)

Continuously growing demand for natural flavors has led to a tremendous increase in biotransformation process employing microorganisms of different genera using ferulic acid (FA) as the precursor. In this study, potential of Lactobacillus farciminis (ATCC 29644) for biotransformation of FA to 4-vinyl guaiacol (4VG) was ...

Preparation of CuS nanoparticles embedded in poly(vinyl alcohol)

Indian Academy of Sciences (India)

Poly(vinyl alcohol) (PVA)/CuS composite nanofibres were successfully prepared by electrospinning technique and gas–solid reaction. Scanning electron microscopic (SEM) images showed that the average diameter of PVA/CuS fibres was about 150–200 nm. Transmission electron microscopy (TEM) proved that a majority ...

Delocalization does not always stabilize : a quantum chemical analysis of -substituent effects on 54 alkyl and vinyl cations

NARCIS (Netherlands)

Alem, van K.; Lodder, G.; Zuilhof, H.

2002-01-01

The effects of -substituents on alkyl and vinyl cations are studied using high-level ab initio calculations. The geometries, stabilities, and electronic properties of 27 alkyl cations and 27 vinyl cations with -substituents are computed at the B3LYP/6-311 G(d,p), MP2/6-311 G(d,p), and CBS-Q levels.

Solid polymer electrolytes based on alternating copolymers of vinyl ethers with methoxy oligo(ethyleneoxy)ethyl groups and vinylene carbonate

International Nuclear Information System (INIS)

Itoh, Takahito; Fujita, Katsuhito; Inoue, Kentaro; Iwama, Hiroki; Kondoh, Kensaku; Uno, Takahiro; Kubo, Masataka

2013-01-01

Graphical abstract: - Highlights: • Synthesis of alternating copolymers of vinyl ethers and vinylene carbonate. • Preparation of polymer electrolytes based on the alternating copolymers with LiTFSI. • Structure-property relationship for alternating copolymers-based electrolytes. • Interfacial stability between polymer electrolytes with lithium metal electrode. - Abstract: Alternating copolymers (poly(1a-g-alt-VC)) of vinyl ethers with various methoxy oligo(ethyleneoxy)ethyl groups and vinylene carbonate (VC) were prepared, and the thermal and electrochemical properties of their polymer electrolytes with LiTFSI and interfacial stability between the polymer electrolyte and Li metal electrode were investigated. T g 's increased linearly with salt contents, and decreased with an increase in the chain length of methoxy oligo(ethyleneoxy)ethyl groups in the vinyl ethers at constant salt concentration. The slopes of T g vs. [Li]/[O] were identical, independent of the polymer structure. The ionic conductivities of the polymer electrolytes increased with increasing the side-chain ethyleneoxy (EO) unit length of the vinyl ether unit in the alternating copolymers, and also their temperature dependences became relatively smaller in the polymer electrolytes having longer EO units in the vinyl ethers. The highest ionic conductivity, 1.2 × 10 −4 S/cm at 30 °C, was obtained in the alternating copolymer with a side-chain EO unit length of 23.5 in the vinyl ether unit. Ion transport coupled with the segmental motion of the polymer is dominant in these polymer electrolytes. Interfacial resistance increased gradually with contact time, indicative of the formation of passivation films on the Li metal electrode. These polymer electrolytes are thermally stable and have large electrochemical windows of use

Terpyridine modified poly(vinyl chloride) : possibilities for supramolecular grafting and crosslinking

NARCIS (Netherlands)

Meier, M.A.R.; Schubert, U.S.

2003-01-01

Commercially available poly(vinyl chloride) (PVC) was covalently modified with terpyridine supramolecular binding units in a two-step reaction. First, PVC was modified with aromatic thiols to introduce OH functionalities into the polymer backbone, which were subsequently reacted with an

Inhibiting the deterioration of plasticised poly (vinyl chloride) in museum collections

DEFF Research Database (Denmark)

Shashoua, Yvonne

2003-01-01

Plasticized poly (vinyl chloride) (PVC) is found in museum collections as three dimensional objects and as packaging materials. Many PVC materials deteriorate within 25 years of acquisition. Migration and chemical breakdown of plasticizer, accompanied by dehydrochlorination of the polymer are the...

Photochemical generation of highly destabilized vinyl cations: the effects of alpha- and beta-trifluoromethyl versus alpha- and beta-methyl substituents

NARCIS (Netherlands)

Alem, van K.; Belder, G.; Lodder, G.; Zuilhof, H.

2005-01-01

The photochemical reactions in methanol of the vinylic halides 1-4, halostyrenes with a methyl or a trifluoromethyl substituent at the - or -position, have been investigated quantitatively. Next to E/Z isomerization, the reactions are formation of vinyl radicals, leading to reductive dehalogenation

Thermal and dynamic mechanical properties of grafted kenaf filled poly (vinyl chloride)/ethylene vinyl acetate composites

International Nuclear Information System (INIS)

Bakar, Nurfatimah Abu; Chee, Ching Yern; Abdullah, Luqman Chuah; Ratnam, Chantara Thevy; Ibrahim, Nor Azowa

2015-01-01

Highlights: • Study on thermal and dynamic mechanical properties of PVC/EVA/PMMA grafted kenaf fiber. • PMMA grafted kenaf fiber showed good interaction with PVC/EVA blends. • Thermal stability of the composites increase upon PMMA grafting on kenaf fiber. • The crystallinity of the composites decrease upon PMMA grafting on kenaf fiber. • PMMA grafted fiber provides more reinforcement on PVC/EVA/grafted PMMA composite. - Abstract: The effects of kenaf and poly (methyl methacrylate grafted kenaf on the thermal and dynamic mechanical properties of poly (vinyl chloride), PVC and ethylene vinyl acetate, EVA blends were investigated. The PVC/EVA/kenaf composites were prepared by mixing the grafted and ungrafted kenaf fiber and PVC/EVA blend using HAAKE Rheomixer at a temperature of 150 °C and the rotor speed at 50 rpm for 20 min. The composites were subjected to Differential Scanning Calorimetric (DSC), Thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), Fourier transform infrared (FTIR) and Scanning Electron Microscopy (SEM) studies. The DSC data revealed that the crystallinity of the EVA decreased with the addition of 30% grafted and ungrafted kenaf fibers. TGA and derivative thermogravimetric (DTG) curves displayed an increase in the thermal stability of the composites upon grafting of the fiber. Studies on DMA indicate that the T g of the PVC and EVA in the PVC/EVA/kenaf composites has been shifted to higher temperature with the addition of the kenaf fiber. The presence of PMMA on the surface of grafted kenaf fiber was further confirmed by the analytical results from FTIR. The morphology of fractured surfaces of the composites, which was examined by a scanning electron microscope, showed the adhesion between the kenaf fiber and the PVC/EVA matrix was improved upon grafting of the kenaf fiber

Contrasting growth properties of Nocardioides JS614 on threedifferent vinyl halides.

Science.gov (United States)

Taylor, Anne E; Bottomley, Peter J; Semprini, Lewis

2018-02-01

Ethene (ETH)-grown inocula of Nocardioides JS614 grow on vinyl chloride (VC), vinyl fluoride (VF), or vinyl bromide (VB) as the sole carbon and energy source, with faster growth rates and higher cell yields on VC and VF than on VB. However, whereas acetate-grown inocula of JS614 grow on VC and VF after a lag period, growth on VB did not occur unless supplemental ethene oxide (EtO) was present in the medium. Despite inferior growth on VB, the maximum rate of VB consumption by ETH-grown cells was ~ 50% greater than the rates of VC and VF consumption, but Br - release during VB consumption was non-stoichiometric with VB consumption (~ 66%) compared to 100% release of Cl - and F - during VC and VF consumption. Evidence was obtained for VB turnover-dependent toxicity of cell metabolism in JS614 with both acetate-dependent respiration and growth being significantly reduced by VB turnover, but no VC or VF turnover-dependent toxicity of growth was detected. Reduced growth rate and cell yield of JS614 on VB probably resulted from a combination of inefficient metabolic processing of the highly unstable VB epoxide (t 0.5  = 45 s), accompanied by growth inhibitory effects of VB metabolites on acetate-dependent metabolism. The exact role(s) of EtO in promoting growth of alkene repressed JS614 on VB remains unresolved, with evidence of EtO inducing epoxide consuming activity prior to an increase in alkene oxidizing activity and supplementing reductant supply when VB is the growth substrate.

Enhanced PL and EL properties of Alq3/nano-TiO2 with the modification of 8-vinyl POSS

Science.gov (United States)

Li, Jie; Xie, Bing; Xia, Kai; Zhao, Chunmao; Li, Yingchun; Hu, Shengliang

2018-04-01

In this study, tris (8-hydroxyquinoline) aluminum/nano-titanium dioxide (Alq3/nano-TiO2) composites were synthesized using a simply in-situ process with 8-vinyl polyhedral oligomeric silsesquioxane (POSS) as a modifier. The as-prepared Alq3/nano-TiO2 composites were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet visible (UV-vis) absorption spectra. The effect of modification on luminescence properties for the samples was studied by photoluminescence (PL) spectra, electroluminescence (EL) spectra and time-resolved luminescence decay curves. Organic light emitting diodes (OLEDs) with the corresponded emitting layer structure were investigated. The results show that the amphiphilicity of the 8-vinyl POSS leads to well-dispersion state of the nano-TiO2 in the Alq3. Adding a proper weight percentage of 8-vinyl POSS is beneficial for the PL and EL properties enhancement of the composites. OLED using the Alq3/nano-TiO2 with 1 wt% 8-vinyl POSS emitting layer has the low turn-on voltage (4.7 V at 1 cd/m2), high maximum luminance (7463 cd/m2 at 8.75 V), and high luminous efficiency (1.13 cd/A at 100 mA/cm2). Adding 1 wt% 8-vinyl POSS in Alq3/nano-TiO2 can increase the EL intensity by a factor of 37.1 at 8 V. These values are better than those for OLEDs using the Alq3 emitting layer. The increase in luminance and current efficiency stability can be attributed to the energy transfer process between the Alq3 and the nano-TiO2, and the suppression of the self-quenching by caged 8-vinyl POSS molecules.

Structure of pyridine and quinoline vinyl ethers according to data from 1H and 13C NMR spectra and quantum-chemical calculations

International Nuclear Information System (INIS)

Afonin, A.V.; Voronov, V.K.; Andriankov, M.A.; Danovich, D.K.

1987-01-01

A systematic investigation of the structure of the vinyl ethers of heterocyclic compounds has not been undertaken. The present work was devoted to investigation of the stereochemical and electronic structure of the vinyl ethers of pyridine and quinoline. The PMR spectra of the samples were recorded for 5% solutions in deuterochloroform on a Tesla BS-497 spectrometer at 100 MHz. The 13 C NMR spectra were recorded on a Tesla BS-567A spectrometer at 25.1 MHz in deuterochloroform with the samples at concentrations of 30%. The internal standard was HMDS. The vinyl ethers of pyridine and quinoline exist preferentially in the nonplanar S-trans conformation. In the vinyl esters of pyridine and quinoline the p-π conjugation is concurrent in nature and depends on the position of the vinyloxy group in the heterocycle

Interaction between poly(vinyl pyridine) and poly(2,6-dimethyl-1,4-phenylene oxide) : A copolymer blend miscibility study

NARCIS (Netherlands)

de Wit, Joost; van Ekenstein, Gert Alberda; ten Brinke, Gerrit

2007-01-01

The phase behavior of blends of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) with random copolymers of styrene and 2-vinyl pyridine, Poly(S-co-2VP), as well as with random copolymers of styrene and 4-vinyl pyridine, Poly(S-co-4VP), has been investigated in order to estimate the values of the

(He 1) photoelectron spectra of vinyl- and (1-dimethylaminovinyl)pyridines

International Nuclear Information System (INIS)

Baidin, V.N.; Koikov, L.N.; Terent'ev, P.B.; Gloriozov, I.P.

1985-01-01

The (He 1) photoelectron spectra of α=, β-, γ-vinyl, α-, β-, and γ-(1-dimethylvinyl)-pyridines, 1-dimethyl- and 1-diethylaminostyrenes were obtained and interpreted within the framework of the molecular orbital perturbation theory. In both pyridine derivative series, there is a regular increase in the ionization energy of the 1α 2 , π/sub C=C/ and n/sub en/ orbitals and decrease in the ionization energy of the 2b 1 orbitals in the order α 2 and 2b 1 is found for γ-vinylpyridine). The splitting of the energy levels of the heterocycle in dimethylaminovinylpyridines is less than in the corresponding vinyl derivatives, which indicates a weakening of the interaction between the aromatic (or heteroaromatic) ring and the enamine fragment extruding from the ring plane. The ionization energy of the unshared electron pair of the nitrogen atom of the pyridine ring for all the compounds except for α- (1-dimethylaminovinyl)pyridine (which displays an ortho effect) is close to that for pyridine. The photoelectron spectral data are compared with the MO energies calculated by the MINDO/3 method

Biomaterial properties evaluation of poly(vinyl acetate- alt-maleic anhydride)/chitosan nanocapsules

Science.gov (United States)

Raţă, Delia Mihaela; Popa, Marcel; Chailan, Jean-François; Zamfir, Carmen Lăcrămioara; Peptu, Cătălina Anişoara

2014-08-01

Nanocapsules with diameter around 100 nm based on a natural polymer (chitosan) and a synthetic polymer poly(vinyl acetate- alt-maleic anhydride) [poly(MAVA)] by interfacial condensation method were prepared. The present study proposes a new type of biocompatible nanocapsules based on poly(vinyl acetate- alt-maleic anhydride-chitosan) (MCS) able to become a reliable support for inclusion and release of drugs. The spherical shape of the nanocapsules was evidenced by scanning electron microscopy. Nanocapsules presented a good Norfloxacin loading and release capacity. Haemocompatibility tests have demonstrated that the nanocapsules present a low toxicity and a good compatibility with sanguine medium. The biocompatibility properties of the nanocapsules after their intraperitoneal administration in rats were evidenced by histopathological examination of different organs (brain, liver, kidney, and lung). The results are encouraging and the nanocapsules can be used as controlled drug delivery systems.

Polysulfone hemodiafiltration membranes with enhanced anti-fouling and hemocompatibility modified by poly(vinyl pyrrolidone) via in situ cross-linked polymerization

Energy Technology Data Exchange (ETDEWEB)

Zhu, Lijing, E-mail: zhulijing@nimte.ac.cn; Song, Haiming; Wang, Jiarong; Xue, Lixin, E-mail: xuelx@nimte.ac.cn

2017-05-01

Poly(vinyl pyrrolidone) (PVP) and its copolymers have been widely employed for the modification of hemodiafiltration membranes due to their excellent hydrophilicity, antifouling and hemocompatibility. However, challenges still remain to simplify the modification procedure and to improve the utilization efficiency. In this paper, antifouling and hemocompatibility polysulfone (PSf) hemodiafiltration membranes were fabricated via in situ cross-linked polymerization of vinyl pyrrolidone (VP) and vinyltriethoxysilane (VTEOS) in PSf solutions and non-solvent induced phase separation (NIPS) technique. The prepared membranes were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), which suggested that VP and VTEOS have been cross-linked copolymerized in PSf membranes. The modified PSf membranes with high polymer content showed improved hydrophilicity, ultrafiltration and protein antifouling ability. In addition, the modified PSf membranes showed lower protein adsorption, inhibited platelet adhesion and deformation, prolonged the activated partial thromboplastin time (APTT), prothrombin time (PT), and decreased the content of fibrinogen (FIB) transferring to fibrin, indicating enhanced hemocompatibility. In a word, the present work provides a simple and effective one-step modification method to construct PSf membranes with improved hydrophilicity, antifouling and hemocompatibility. - Highlights: • PSf membranes were modified by in situ cross-linked polymerization. • The modified PSf membranes showed enhanced hydrophilicity. • The anti-fouling and hemocompatibility of PSf membranes were improved.

Polysulfone hemodiafiltration membranes with enhanced anti-fouling and hemocompatibility modified by poly(vinyl pyrrolidone) via in situ cross-linked polymerization

International Nuclear Information System (INIS)

Zhu, Lijing; Song, Haiming; Wang, Jiarong; Xue, Lixin

2017-01-01

Poly(vinyl pyrrolidone) (PVP) and its copolymers have been widely employed for the modification of hemodiafiltration membranes due to their excellent hydrophilicity, antifouling and hemocompatibility. However, challenges still remain to simplify the modification procedure and to improve the utilization efficiency. In this paper, antifouling and hemocompatibility polysulfone (PSf) hemodiafiltration membranes were fabricated via in situ cross-linked polymerization of vinyl pyrrolidone (VP) and vinyltriethoxysilane (VTEOS) in PSf solutions and non-solvent induced phase separation (NIPS) technique. The prepared membranes were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), which suggested that VP and VTEOS have been cross-linked copolymerized in PSf membranes. The modified PSf membranes with high polymer content showed improved hydrophilicity, ultrafiltration and protein antifouling ability. In addition, the modified PSf membranes showed lower protein adsorption, inhibited platelet adhesion and deformation, prolonged the activated partial thromboplastin time (APTT), prothrombin time (PT), and decreased the content of fibrinogen (FIB) transferring to fibrin, indicating enhanced hemocompatibility. In a word, the present work provides a simple and effective one-step modification method to construct PSf membranes with improved hydrophilicity, antifouling and hemocompatibility. - Highlights: • PSf membranes were modified by in situ cross-linked polymerization. • The modified PSf membranes showed enhanced hydrophilicity. • The anti-fouling and hemocompatibility of PSf membranes were improved.

Synthesis and characterization of foldable and magnetic field-sensitive, freestanding poly(vinyl acetate)/poly(vinyl chloride)/polyfuran composite and nanocomposite films

Energy Technology Data Exchange (ETDEWEB)

Sarıtaş, Sevilay; Eşsiz, Serpil; Sarı, Bekir, E-mail: bsari@gazi.edu.tr

2017-07-01

Highlights: • In this study, ternary composite/nanocomposite films were synthesized. • Magnetic field-sensitive folding films were prepared without any elastomer. • Morphological studies show that all composite films have a smooth surface. • The ternary composites/nanocomposite show improved thermal stability compared to the pure PF. - Abstract: In this study, polyfuran and poly(vinyl acetate)/poly(vinyl chloride)/polyfuran ternary composites were synthesized via the chemical polymerization method. The temperature and magnetic field–sensitive novel composites and the nanocomposite were obtained in the form of powders and films. It was observed that the prepared novel conductive films have superior properties at a certain temperature range (25–50 °C) such as bending and folding. The structural properties, thermal behavior, surface morphology, internal structure, and surface roughness of the prepared samples were investigated by various characterization techniques. The conductivities of the samples were measured at room temperature and different temperatures by the four-point technique. X-ray Diffraction analysis results demonstrated that the PF and composites have an amorphous structure, whereas the nanocomposite is in crystalline form. The saturation magnetization (Ms) values of the magnetite and nanocomposite were found to be 58.9 and 5.3 emu g{sup −1}, respectively. It was found that magnetite-doped nanocomposite has superparamagnetic properties at room temperature.

Reactivity of vinyl ethers and vinyl ribosides in UV-initiated free radical copolymerization with acceptor monomers.

Science.gov (United States)

Pichavant, Loic; Guillermain, Céline; Coqueret, Xavier

2010-09-13

The reactivity of various vinyl ethers and vinyloxy derivatives of ribose in the presence of diethyl fumarate or diethyl maleate was investigated for evaluating the potential of donor-acceptor-type copolymerization applied to unsaturated monomers derived from renewable feedstock. The photochemically induced polymerization of model monomer blends in the bulk state was monitored by infrared spectroscopy. The method allowed us to examine the influence of monomer pair structure on the kinetic profiles. The simultaneous consumption of both monomers was observed, supporting an alternating copolymerization mechanism. A lower reactivity of the blends containing maleates compared with fumarates was confirmed. The obtained kinetic data revealed a general correlation between the initial polymerization rate and the Hansen parameter δ(H) associated with the H-bonding aptitude of the donor monomer.

High performances unsaturated polyester based nanocomposites: Effect of vinyl modified nanosilica on mechanical properties

Directory of Open Access Journals (Sweden)

J. D. Rusmirovic

2016-02-01

Full Text Available Influences of the vinyl modified nanosilica Aerosil® 380, i.e./i>, vinyl and methacryloyl silane coupling agent and linseed oil fatty acids (BD reactive residues, on the mechanical properties of the unsaturated polyester resins (UPes based nanocomposites, was studied. The polycondensation of maleic anhydride and products of poly(ethylene terephthalate (PET depolymerization with propylene glycol, with and without separation of ethylene glycol, yields UPe1 and UPe2 resin, respectively. The hydroxyl terminated PET depolymerization products (glycolyzates and UPes were characterized by acid and hydroxyl values, Fourier Transform Infrared (FTIR and nuclear magneti resonance (NMR spectroscopies. Transmission electron microscopy (TEM confirmed that silica nanoparticles formed domains of aggregates in the polymer matrix. An increase from 195 to 247% of stress at break (σb, and from 109 to 131% of impact strength (σi of UPes based nanocomposites was obtained for 1 wt% addition of vinyl modified silica. Flexural strength (σf increase from 106 to 156% for both UPes based nanocomposites with 1 wt% addition of BD modified silica. Cross-linking density (ν, storage modulus (G', tanδ and Tg of the nanocomposite were determined from the dynamic mechanical testing and discussed in relation to the structure of silica modification.

Nanocomposite photoactuators based on an ethylene vinyl acetate copolymer filled with carbon nanotubes

Czech Academy of Sciences Publication Activity Database

Czaniková, K.; Torras, N.; Esteve, J.; Krupa, I.; Kasák, P.; Pavlova, Ewa; Račko, D.; Chodák, I.; Omastová, M.

2013-01-01

Roč. 186, September (2013), s. 701-710 ISSN 0925-4005 Institutional support: RVO:61389013 Keywords : actuator * carbon nanotubes * ethylene vinyl acetate copolymer Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.840, year: 2013

Synthesis of Ethylene or Propylene/1,3-Butadiene Copolymers Possessing Pendant Vinyl Groups with Virtually No Internal Olefins

OpenAIRE

Kenji Michiue; Makoto Mitani; Terunori Fujita

2015-01-01

In general, ethylene/1,3-butadiene copolymerizations provides copolymers possessing both pendant vinyls and vinylenes as olefinic moieties. We, at MCI, studied the substituent effects of C2-symmetric zirconocene complexes, rac-[Me2Si(Indenyl’)2]ZrCl2 (Indenyl’ = generic substituted indenyl), after activation on the ratio of the pendant vinyls and vinylenes of the resultant copolymers. Complexes examined in this study were rac-dimethylsilylbis (1-indenyl)zirconium dichloride (1), rac-dimethyls...

The γ-radiation induced grafting of unsaturated segmented polyurethanes with N-vinyl pyrrolidone

International Nuclear Information System (INIS)

Egboh, S.H.; George, M.H.; Barrie, J.A.

1984-01-01

Linear unsaturated segmented polyurethanes have been modified by hydrophilic grafting at 40 deg C with N-vinyl pyrrolidone, in N,N-dimethylformamide as solvent, using 60 Cobalt γ-irradiation. Graft copolymers were isolated from homopolymers by selective solvent extraction using a Soxhlet apparatus. The effects of reaction time, total dose, temperature and monomer concentration, on the graft yields have been examined. Relatively high irradiation doses were avoided during the grafting experiments to prevent possible degradation of the segmented polyurethanes and gelation of the homopolymer, poly(N-vinyl pyrrolidone). The ungrafted and grafted copolymers were characterized, and the graft copolymers were shown to be more thermally stable than the original polyurethanes, by thermogravimetric analysis. An explanation for the observed variation of the graft yields with some of the experimental variables is suggested. (author)

Wax inhibitor based on ethylene vinyl acetate with methyl methacrylate and diethanolamine for crude oil pipeline

Science.gov (United States)

Anisuzzaman, S. M.; Abang, S.; Bono, A.; Krishnaiah, D.; Karali, R.; Safuan, M. K.

2017-06-01

Wax precipitation and deposition is one of the most significant flow assurance challenges in the production system of the crude oil. Wax inhibitors are developed as a preventive strategy to avoid an absolute wax deposition. Wax inhibitors are polymers which can be known as pour point depressants as they impede the wax crystals formation, growth, and deposition. In this study three formulations of wax inhibitors were prepared, ethylene vinyl acetate, ethylene vinyl acetate co-methyl methacrylate (EVA co-MMA) and ethylene vinyl acetate co-diethanolamine (EVA co-DEA) and the comparison of their efficiencies in terms of cloud point¸ pour point, performance inhibition efficiency (%PIE) and viscosity were evaluated. The cloud point and pour point for both EVA and EVA co-MMA were similar, 15°C and 10-5°C, respectively. Whereas, the cloud point and pour point for EVA co-DEA were better, 10°C and 10-5°C respectively. In conclusion, EVA co-DEA had shown the best % PIE (28.42%) which indicates highest percentage reduction of wax deposit as compared to the other two inhibitors.

Positron scattering from vinyl acetate

International Nuclear Information System (INIS)

Chiari, L; Brunger, M J; Zecca, A; Blanco, F; García, G

2014-01-01

Using a Beer–Lambert attenuation approach, we report measured total cross sections (TCSs) for positron scattering from vinyl acetate (C 4 H 6 O 2 ) in the incident positron energy range 0.15–50 eV. In addition, we also report an independent atom model with screening corrected additivity rule computation results for the TCSs, differential and integral elastic cross sections, the positronium formation cross section and inelastic integral cross sections. The energy range of these calculations is 1–1000 eV. While there is a reasonable qualitative correspondence between measurement and calculation for the TCSs, in terms of the energy dependence of those cross sections, the theory was found to be a factor of ∼2 larger in magnitude at the lower energies, even after the measured data were corrected for the forward angle scattering effect. (paper)

Cel vinyls: materials and methods.

Science.gov (United States)

Harrison, S J

1983-12-01

Many commercial uses of media are applicable to medical/scientific media production and illustration, not the least of which are techniques pioneered in the commercial cartooning field. Whether or not the illustrative effort culminates in a "cartoon," the production techniques of the cartooning industry cannot be overlooked by the illustrator faced with providing projection graphics, whether animated or still, for slides, motion pictures, television or even print media. When Walt Disney introduced Mickey Mouse as "Steamboat Willie" in 1928, his technology opened the door for exploration of cartooning media by all artists. Only in comparatively recent years have these tools been used by the scientific illustrator. In this article cel vinyl acrylics or cartoon colors will be discussed: the rationale for the use of this medium, materials and methods, and considerations related to the photography of this art form.

Design, synthesis, and biological evaluation of 3-vinyl-quinoxalin-2(1H-one derivatives as novel antitumor inhibitors of FGFR1

Directory of Open Access Journals (Sweden)

Liu Z

2016-05-01

Full Text Available Zhiguo Liu,1,* Shufang Yu,1,* Di Chen,1 Guoliang Shen,1 Yu Wang,1 Leping Hou,2 Dan Lin,1 Jinsan Zhang,1 Faqing Ye1 1School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 2Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, People’s Republic of China *These authors contributed equally to this work Abstract: FGFR1 is well known as a molecular target in anticancer drug design. TKI258 plays an important role in RTK inhibitors. Utilizing TKI258 as a lead compound that contains a quinazolinone nucleus, we synthesized four series of 3-vinyl-quinoxalin-2(1H-one derivatives, a total of 27 compounds. We further evaluated these compounds for FGFR1 inhibition ability as well as cytotoxicity against four cancer cell lines (H460, B16-F10, Hela229, and Hct116 in vitro. Some compounds displayed good-to-excellent potency against the four tested cancer cell lines compared with TKI258. Structure–activity relationship analyses indicated that small substituents at the side chain of the 3-vinyl-quinoxalin-2(1H-one were more effective than large substituents. Lastly, we used molecular docking to obtain further insight into the interactions between the compounds and FGFR1. Keywords: FGFR1, synthesis, quinoxaline, antitumor activity, kinase inhibitor

Occurrence, characterization and analysis of vinyl chloride as a degradation product of chloro ethenes from waste sites. Vorkommen, Beurteilung und Analytik von Vinylchlorid als Abbauprodukt chlorierter Ethene in Altlasten

Energy Technology Data Exchange (ETDEWEB)

Koester, M. (Harress Geotechnik GmbH, Harburg (Germany, F.R.))

1989-12-01

Reductive dehalogenation reactions occuring within the central part of contaminated areas may result in the formation of vinyl chloride as a product of chlorinated hydrocarbon degradation. This degradation takes place in an anaerobic environment, and proceeds from tetrachloroethene through trichloroethene and dichloroethene (cis, trans) to vinyl chloride. The analysis of vinyl chloride from gas and water samples is performed by means of capillary gas chromatography, using a flame ionization detector (FID). It could be shown from the analysis of some 200 samples from various tetrachloroethene and trichloroethene waste sites, that high dichloroethene concentrations were correlated with elevated vinyl chloride concentrations. The ratio between dichloroethene and vinyl chloride although depending on the chemical and physical properties of the subsoil, is roughly 10:1. Since vinyl chloride is known to be carcinogenic, action levels and clean-up standards are accordingly low, resulting in new requirement for remedial activities. (orig.).

Preparation of Macroporous Poly (vinyl alcohol-co-triallyl isocyanurate) Beads Bearing Aminocarboxylic Acid as Functional Groups by Suspension Polymerization

Institute of Scientific and Technical Information of China (English)

无

2003-01-01

Macroporous poly (vinyl acetate-co-triallyl isocyanurate) beads were prepared with suspension polymerization method. The copolymer beads were then transformed into poly (vinyl alcohol-co-triallyl isocyanurate) by ester exchange reaction. Aminocarboxylic acids were immobilized on the copolymer beads by the esterification of hydroxyl groups with diethyl-lenetriaminepentaacetic bisanhydride. The weak acid exchange capacities, specific surface areas and mean pore diameters of the resultant resin beads were measured.

Fabrication of 3D interconnected porous TiO{sub 2} nanotubes templated by poly(vinyl chloride-g-4-vinyl pyridine) for dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Koh, Joo Hwan; Koh, Jong Kwan; Seo, Jin Ah; Kim, Jong Hak [Department of Chemical and Biomolecular Engineering, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Shin, Jong-Shik, E-mail: jonghak@yonsei.ac.kr [Department of Biotechnology, Yonsei University, 262 Seongsanno, Seodaemun-gu, Seoul 120-749 (Korea, Republic of)

2011-09-07

Porous TiO{sub 2} nanotube arrays with three-dimensional (3D) interconnectivity were prepared using a sol-gel process assisted by poly(vinyl chloride-graft-4-vinyl pyridine), PVC-g-P4VP graft copolymer and a ZnO nanorod template. A 7 {mu}m long ZnO nanorod array was grown from the fluorine-doped tin oxide (FTO) glass via a liquid phase deposition method. The TiO{sub 2} sol-gel solution templated by the PVC-g-P4VP graft copolymer produced a random 3D interconnection between the adjacent ZnO nanorods during spin coating. Upon etching of ZnO, TiO{sub 2} nanotubes consisting of 10-15 nm nanoparticles were generated, as confirmed by wide-angle x-ray scattering (WAXS), energy-filtering transmission electron microscopy (EF-TEM) and field-emission scanning electron microscopy (FE-SEM). The ordered and interconnected nanotube architecture showed an enhanced light scattering effect and increased penetration of polymer electrolytes in dye-sensitized solar cells (DSSC). The energy conversion efficiency reached 1.82% for liquid electrolyte, and 1.46% for low molecular weight (M{sub w}) and 0.74% for high M{sub w} polymer electrolytes.

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

International Nuclear Information System (INIS)

Heinze, D.; Mang, Th.; Popescu, C.; Weichold, O.

2016-01-01

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_3–(CH_2CH (OCO(CH_2)_mCH_3))_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.

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.

Composite poly(vinyl alcohol/poly(vinyl acetate electrospun nanofibrous mats as a novel wound dressing matrix for controlled release of drugs

Directory of Open Access Journals (Sweden)

Jannesari M

2011-05-01

Full Text Available Marziyeh Jannesari1, Jaleh Varshosaz2, Mohammad Morshed1, Maedeh Zamani11Department of Textile Engineering, Isfahan University of Technology, Isfahan, Iran; 2Department of Pharmaceutics, School of Pharmacy and Pharmaceutical Sciences Research Center, Isfahan University of Medical Sciences, Isfahan, IranAbstract: The aim of this study was to develop novel biomedicated nanofiber electrospun mats for controlled drug release, especially drug release directly to an injury site to accelerate wound healing. Nanofibers of poly(vinyl alcohol (PVA, poly(vinyl acetate (PVAc, and a 50:50 composite blend, loaded with ciprofloxacin HCl (CipHCl, were successfully prepared by an electrospinning technique for the first time. The morphology and average diameter of the electrospun nanofibers were investigated by scanning electron microscopy. X-ray diffraction studies indicated an amorphous distribution of the drug inside the nanofiber blend. Introducing the drug into polymeric solutions significantly decreased solution viscosities as well as nanofiber diameter. In vitro drug release evaluations showed that both the kind of polymer and the amount of drug loaded greatly affected the degree of swelling, weight loss, and initial burst and rate of drug release. Blending PVA and PVAc exhibited a useful and convenient method for electrospinning in order to control the rate and period of drug release in wound healing applications. Also, the thickness of the blend nanofiber mats strongly influenced the initial release and rate of drug release.Keywords: biodegradable polymers, drug delivery, controlled release, electrospun nanofibers, wound dressing

Influence of acrylonitrile butadiene rubber on recyclability of blends prepared from poly(vinyl chloride) and poly(methyl methacrylate).

Science.gov (United States)

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

2018-06-01

The current investigation deals with the recycling possibilities of poly(vinyl chloride) and poly(methyl methacrylate) in the presence of acrylonitrile butadiene rubber. Recycled blends of poly(vinyl chloride)/poly(methyl methacrylate) are successfully formed from the plastic constituents, those are recovered from waste computer products. However, lower impact performance of the blend and lower stability of the poly(vinyl chloride) phase in the recycled blend restricts its further usage in industrial purposes. Therefore, effective utilisation acrylonitrile butadiene rubber in a recycled blend was considered for improving mechanical and thermal performance. Incorporation of acrylonitrile butadiene rubber resulted in the improvement in impact performance as well as elongation-at-break of the recycled blend. The optimum impact performance was found in the blend with 9 wt% acrylonitrile butadiene rubber, which shows 363% of enhancement as compared with its parent blend. Moreover, incorporated acrylonitrile butadiene rubber also stabilises the poly(vinyl chloride) phase present in the recycled blend, similarly Fourier transform infrared spectroscopy studies indicate the interactions of various functionalities present in the recycled blend and acrylonitrile butadiene rubber. In addition to this, thermogravimetric analysis indicates the improvement in the thermal stability of the recycled blend after the addition of acrylonitrile butadiene rubber into it. The existence of partial miscibility in the recycled blend was identified using differential scanning calorimetry and scanning electron microscopy.

Poly(vinyl alcohol) cryogel phantoms for use in ultrasound and MR imaging

International Nuclear Information System (INIS)

Surry, K J M; Austin, H J B; Fenster, A; Peters, T M

2004-01-01

Poly(vinyl alcohol) cryogel, PVA-C, is presented as a tissue-mimicking material, suitable for application in magnetic resonance (MR) imaging and ultrasound imaging. A 10% by weight poly(vinyl alcohol) in water solution was used to form PVA-C, which is solidified through a freeze-thaw process. The number of freeze-thaw cycles affects the properties of the material. The ultrasound and MR imaging characteristics were investigated using cylindrical samples of PVA-C. The speed of sound was found to range from 1520 to 1540 m s -1 , and the attenuation coefficients were in the range of 0.075-0.28 dB (cm MHz) -1 . T1 and T2 relaxation values were found to be 718-1034 ms and 108-175 ms, respectively. We also present applications of this material in an anthropomorphic brain phantom, a multi-volume stenosed vessel phantom and breast biopsy phantoms. Some suggestions are made for how best to handle this material in the phantom design and development process

Aging Characteristics and Effect of Gamma Radiation on Ethylene Vinyl Acetate Copolymer

International Nuclear Information System (INIS)

Alya, S.S.; Hegazy, E.A.; Senb, M.; El-Oker, M.M.

2008-01-01

Artificial aging of Ethylene vinyl acetate copolymer (EVA-13% vinyl acetate content) exposed to thermal aging at 80 degree C, to UV irradiation with wavelength close to 259 nm and to gamma radiation up to 377 kGy, in the presence of air, has been studied. FTIR measurements were performed to follow the chemical changes, which may occur in the samples during aging. The IR study indicated that, some chemical changes took place during thermal, UV aging and gamma irradiation. The formation of Ketone and Lactone groups at 1715 and 1780 cm-1, respectively, were observed for all samples. DSC thermo grams of thermally aged samples revealed a shift to higher temperature of the melting point and the crystallinity increased with increasing aging time for all the thermally treated and cooled samples at different conditions. For gamma-irradiated samples, a slight decrease in the melting point was observed and the degree of crystallinity increased almost linearly up to 200 kGy

Fixation of some chemically modified reactive dye during gamma irradiation of cotton fabrics in presence of vinyl and acrylic monomers

International Nuclear Information System (INIS)

Zohdy, M.H.; El-Naggar, A.M.; Abdallah, W.A.

1999-01-01

The radiation grafting of vinyl sulfone dye having an activated double bond in presence of styrene monomer or its mixtures with ethyl acrylate onto cotton fabric has been investigated. The chemical reaction of the vinyl sulfone form with peroxy radicals on cotton fabric through covalent bonding is tested by extracting the dyed samples in 50% aqueous DMF solution. It was found that the presence of styene monomer in the dyeing solution is essential for the reaction or grafting of the vinyl sulfone dye. However, when a constant styrene concentration of 5% was used in the dye bath, the color strength expressed as K/S was found to increase by increasing the dye concentration. The results showed that the color strength obtained in case of using 10% ethyl acrylate is much lower than in the case of using the same concentration of styrene monomer. A solvent composition of equal ratios of methanol and water has been proven to be suitable to produce the highest improvement in the color strength. The irradiation dose was found to play an important role in initiating the reaction of the vinyl sulfone dye

Changes in chemical permeation of disposable latex, nitrile, and vinyl gloves exposed to simulated movement.

Science.gov (United States)

Phalen, Robert N; Le, Thi; Wong, Weng Kee

2014-01-01

Glove movement can affect chemical permeation of organic compounds through polymer glove products. However, conflicting reports make it difficult to compare the effects of movement on chemical permeation through commonly available glove types. The aim of this study was to evaluate the effect of movement on chemical permeation of an organic solvent through disposable latex, nitrile, and vinyl gloves. Simulated whole-glove permeation testing was conducted using ethyl alcohol and a previously designed permeation test system. With exposure to movement, a significant decrease (p ≤ 0.001) in breakthrough time (BT) was observed for the latex (-23%) and nitrile gloves (-31%). With exposure to movement, only the nitrile glove exhibited a significant increase (p ≤ 0.001) in steady-state permeation rate (+47%) and cumulative permeation at 30 min (+111%). Even though the nitrile glove provided optimum chemical resistance against ethyl alcohol, it was most affected by movement. With exposure to movement, the latex glove was an equivalent option for overall worker protection, because it was less affected by movement and the permeation rate was lower than that of the nitrile glove. In contrast, the vinyl glove was the least affected by movement, but did not provide adequate chemical resistance to ethyl alcohol in comparison with the nitrile and latex gloves. Glove selection should take movement and polymer type into account. Some glove polymer types are less affected by movement, most notably the latex glove in this test. With nitrile gloves, at least a factor of three should be used when attempting to assign a protection factor when repetitive hand motions are anticipated. Ultimately, the latex gloves outperformed nitrile and vinyl in these tests, which evaluated the effect of movement on chemical permeation. Future research should aim to resolve some of the observed discrepancies in test results with latex and vinyl gloves.

/sup 13/C-/sup 13/C spin-spin coupling constants in structural investigations. II. Conformational structure of vinyl ethers

Energy Technology Data Exchange (ETDEWEB)

Krivdin, L.B.; Shcherbakov, V.V.; Bzhezovskii, V.M.; Kalabin, G.A.

1986-10-10

The /sup 13/C-/sup 13/C spin-spin coupling constants between the carbon nuclei of the vinyl group were measured for a series of vinyl ethers. It was established that the unshared electron pairs of the oxygen atom can make a substantial stereospecific contribution to the direct /sup 13/C-/sup 13/C constants of the adjacent nuclei. The observed effect was used to establish the conformational structure of the compounds.

Microstructure and molecular interaction in glycerol plasticized chitosan/poly(vinyl alcohol) blending films

Science.gov (United States)

Poly (vinyl alcohol) (PVA)/chitosan (CS) blended films plasticized by glycerol were investigated using mechanical testing, atomic force microscopy (AFM), differential scanning calorimetry (DSC) and FTIR spectroscopy, with primary emphasis on the effects of the glycerol content and the molecular weig...

Study of the influence of the molecular structure of vinyl compounds on their ability to form polymer films by electro-polymerization under cathodic polarisation

International Nuclear Information System (INIS)

Deniau, Guy

1990-01-01

This research thesis addresses the study of new vinyl compounds, and aims at improving knowledge on the interaction between metal and a vinyl molecule under an intense electric field (the field of the double electrochemical layer), and more particularly at studying the influence of the molecular structure of the vinyl compound as well as the occurring reactions. After a first part presenting physical-chemical principles and knowledge which govern the whole set of reactions which are occurring within an electrolysis reactor, and a brief historical overview, this research thesis proposes a presentation of molecules which have been chosen for this study (vinyl compounds) and a justification of this choice. The author also presents the experimental device and describes the process implementation. Then, he presents and analyses experimental results. It appears that only some studied molecules result in the formation of polymer film [fr

A Review of Natural Fiber Reinforced Poly(Vinyl Alcohol Based Composites: Application and Opportunity

Directory of Open Access Journals (Sweden)

Boon Khoon Tan

2015-11-01

Full Text Available Natural fibers are fine examples of renewable resources that play an important role in the composites industry, which produces superior strength comparable to synthetic fibers. Poly(vinyl alcohol (PVA composites in particular have attracted enormous interest in view of their satisfactory performance, properties and biodegradability. Their performance in many applications such as consumer, biomedical, and agriculture is well defined and promising. This paper reviews the utilization of natural fibers from macro to nanoscale as reinforcement in PVA composites. An overview on the properties, processing methods, biodegradability, and applications of these composites is presented. The advantages arising from chemical and physical modifications of fibers or composites are discussed in terms of improved properties and performance. In addition, proper arrangement of nanocellulose in composites helps to prevent agglomeration and results in a better dispersion. The limitations and challenges of the composites and future works of these bio-composites are also discussed. This review concludes that PVA composites have potential for use in numerous applications. However, issues on technological feasibility, environmental effectiveness, and economic affordability should be considered.

Elution behavior of poly(ethylene glycol) through poly(vinyl alcohol) gel column using several solvents as eluents

International Nuclear Information System (INIS)

Hirayama, Chuichi; Motozato, Yoshiaki; Matsumoto, Kazuaki.

1983-01-01

γ-Irradiated poly(vinyl alcohol) beads, which were sufficiently allowed to swell in water, were washed with methanol, and then were packed into column. Gel chromatography was performed using methanol, benzene, esters and ketones as eluents and poly(ethylene glycol) as a sample. When the elution was carried out using methanol and benzene as eluents, elution behavior of samples was ordinary. When ethyl formate, methyl acetate and ethyl propionate were used as eluents, samples were slightly adsorbed and the elution was delayed. In the case the elution was carried out using ethyl acetate, propyl acetate, butyl acetate and ethyl methyl ketone as eluents, samples were adsorbed strongly on the bed material, and the adsorption curve was analogous to the calibration curve using methanol as an eluent. Dried poly(vinyl alcohol) gel as a packing material, showed ordinary elution behaviors for the samples. The adsorption of poly(ethylene glycol) on the present bed material was attributed to the existence of hydrated water on poly(vinyl alcohol) gel matrix. (author)

The Inhibition of Aluminum Corrosion in Sulfuric Acid by Poly(1-vinyl-3-alkyl-imidazolium Hexafluorophosphate).

Science.gov (United States)

Arellanes-Lozada, Paulina; Olivares-Xometl, Octavio; Guzmán-Lucero, Diego; Likhanova, Natalya V; Domínguez-Aguilar, Marco A; Lijanova, Irina V; Arce-Estrada, Elsa

2014-08-07

Compounds of poly(ionic liquid)s (PILs), derived from imidazole with different alkylic chain lengths located in the third position of the imidazolium ring (poly(1-vinyl-3-dodecyl-imidazolium) (PImC 12 ), poly(1-vinyl-3-octylimidazolium) (PImC₈) and poly(1-vinyl-3-butylimidazolium) (PImC₄) hexafluorophosphate) were synthesized. These compounds were tested as corrosion inhibitors on aluminum alloy AA6061 in diluted sulfuric acid (0.1-1 M H₂SO₄) by weight loss tests, polarization resistance measurements and inductively coupled plasma optical emission spectroscopy. Langmuir's isotherms suggested film formation on bare alloy while standard free energy indicated inhibition by a physisorption process. However, compound efficiencies as inhibitors ranked low (PImC 12 > PImC₈ > PImC₄) to reach 61% for PImC 12 in highly diluted acidic solution. Apparently, the high mobility of sulfates favored their adsorption in comparison to PILs. The surface film displayed general corrosion, and pitting occurred as a consequence of PILs' partial inhibition along with a continuous dissolution of defective patchy film on formation. A slight improvement in efficiency was displayed by compounds having high molecular weight and a long alkyl chain, as a consequence of steric hindrance and PIL interactions.

Predicting Residential Exposure to Phthalate Plasticizer Emitted from Vinyl Flooring - A Mechanistic Analysis

Science.gov (United States)

A two-room model is developed to estimate the emission rate of di-2-ethylhexyl phthalate (DEHP) from vinyl flooring and the evolving gas-phase and adsorbed surface concentrations in a realistic indoor environment. Adsorption isotherms for phthalates and plasticizers on interior ...

Study on radiation effect of poly (vinyl alcohol) films irradiated by tritium decay

International Nuclear Information System (INIS)

Li Hairong; Peng Shuming; Zhou Xiaosong; Yu Mingming; Xia Lidong; Chen Xiaohua; Liang Jianhua

2014-01-01

The radiation effect of poly(vinyl alcohol) films used as a kind of gas-barrier material for inertial confinement fusion (ICF) targets was studied under the different conditions of β-ray from tritium decay. The changes of physical and chemical properties of the irradiated material samples were analyzed by FTIR, XRD and AFM. The tritium-hydrogen isotopic exchange reaction of the irradiated samples mainly occurs at C-H bond and the IR absorption peak of C-T bond obviously increases with the irradiation dose. For strong hydrogen bonding interaction, the isotopic exchange reaction doesn't occur at O-H bond. The crystallinity degree and surface morphology of the irradiated samples were changed. The tensile properties of irradiated poly(vinyl alcohol) films were measured by universal material testing machine. The results show that the change trend of mechanical properties is in accordance with the microstructures of the irradiated samples. (authors)

Novel route to 5-position vinyl derivatives of thiolactomycin: Olefination vs. deformylation

Science.gov (United States)

Kim, Pilho; Barry, Clifton E.; Dowd*, Cynthia S.

2006-01-01

Vinyl and diene derivatives of thiolactomycin have been prepared via Horner-Wadsworth-Emmons olefination from protected 5-formyl-3,5-dimethylthiotetronic acid. Several 4-position protecting groups and a variety of phosphonates were evaluated, with MOM protection and β-ketophosphonates yielding the highest ratio of desired product to deformylated product. PMID:16699591

Synthesis and reactivity ratios of regioisomeric vinyl-1,2,3-triazoles with styrene

NARCIS (Netherlands)

Lartey, M; Gillissen, M.A.J.; Adzima, B.J.; Takizawa, K.; Luebke, D.R.; Nulwala, H.B.

2013-01-01

The free radical reactivity ratios between styrene and different vinyl-1,2,3-triazole regioisomeric monomers in 1,4-dioxane at 65 degrees C have been established using nonlinear least square method. The results obtained for the reactivity ratio between regioisomers show exceptionally different

Concurrent coordination of ligand in metal chloride complexes with 1-vinyl-2-(2-pyridyl)benzimidazole

International Nuclear Information System (INIS)

Bajkalov, L.V.; Domnina, E.S.

1996-01-01

The properties and structure of bivalent cadmium and 1-vinyl-2-(2-pyridyl)benzimidazole chloride complexes, which have been prepared for the first time, have been studied by the methods of potentiometric titration and PMR, 35 Cl NQR, UV and IR spectroscopy. For the complexes above di- and polymeric structures in crystal phase are suggested, where ligand plays the role of a bridge. N,N-bidentate ligand. In solution the complexes dissociate with formation of monomeric coordination compounds, their metal being bound by different ways, stemming from participation of N benzimidazole or pyridine fragment of the ligand. Adducts of ionic type with second sphere 1-vinyl-2-(2-pyridyl)benzimidazole cation have been obtained in the course of hydrochlorination of the complexes prepared

Evaluation of morphology and cell behaviour of a novel synthesized electrospun poly(vinyl pyrrolidone/poly(vinyl alcohol/hydroxyapatite nanofibers

Directory of Open Access Journals (Sweden)

Raheleh Faridi-Majidi

2017-04-01

Full Text Available Objective(s: Three-dimensional structures such as nanofibrous scaffolds are being used in biomedical engineering as well as provide a site for cells to attach and proliferate leading to tissue formation. In the present study, poly(vinyl pyrrolidone (PVP/ poly(vinyl alcohol(PVA hybrid nanofibrous scaffold was synthesized by electrospinning. Materials and Methods: The effect of adding nano hydroxyapatite (n-HA and also Epoxypropoxy-propyl-trimethoxysilane (EPPTMS as a crosslinking agent on morphology and cell behaviour of the nanofibers was investigated.Results: Scanning electron microscope (SEM observations showed that all kinds of nanofibers represented uniform and well-ordered morphologies without formation of any beads by controlling the synthesis parameters. The average ûber diameter of PVP-PVA was 260 nm. n-HA was synthesized by wet chemical process. The synthesized n-HA was characterized by XRD for structural analysis. Transmission electron microscope (TEM revealed that HA particles had nanosized dimensions (in the range of 40-100 nm. The presence of n-HA within electrospun PVP-PVA nanofibers was confirmed by XRD and Fourier transmission infrared spectroscopy (FTIR analyses. The average ûber diameter was decreased to 136 nm when n-HA was added in the composition of PVP-PVA. FTIR analysis depicted that PVP-PVA nanofibers were linked to EPPTMS as a biocompatible material by the covalent bond. Although adding n-HA caused to decrease the diameter of PVP-PVA nanofibers, addition of EPPTMS within PVP/PVA/n-HA nanofibers induced increasing distribution of fiber diameter as it enhanced to 195nm. In addition, the proper proliferation of G292 osteoblastic cells without any cytotoxicity was observed for the nanofiber.Conclusion: Since these materials have been known as biomaterials, PVP/PVA/n-HA-EPPTMS nanofibers can be propounded as a good candidate for bone tissue engineering application.

Halloysite nanotubes grafted hyperbranched (co)polymers via surface-initiated self-condensing vinyl (co)polymerization

International Nuclear Information System (INIS)

Mu Bin; Zhao Mingfei; Liu Peng

2008-01-01

Halloysite nanotubes (HNTs) grafted hyperbranched polymers were prepared by the self-condensing vinyl polymerization (SCVP) of 2-((bromoacetyl)oxy)ethyl acrylate (BAEA) and the self-condensing vinyl copolymerization of n-butyl acrylate (BA) and BAEA with BAEA as inimer (AB*) respectively, from the surfaces of the 2-bromoisobutyric acid modified halloysite nanotubes (HNTs-Br) via atom transfer radical polymerization (ATRP) technique. The halloysite nanotubes grafted hyperbranched polymer (HNTs-HP) and the halloysite nanotubes grafted hyperbranched copolymer (HNTs-HCP) were characterized by elemental analysis (EA), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and transmission electron microscope (TEM). The grafted hyperbranched polymers were characterized with Nuclear magnetic resonance (NMR) and the molecular ratio between the inimer AB* and BA in the grafted hyperbranched copolymers was found to be 3:2, calculated from the TGA and EA results

Halloysite nanotubes grafted hyperbranched (co)polymers via surface-initiated self-condensing vinyl (co)polymerization

Energy Technology Data Exchange (ETDEWEB)

Mu Bin; Zhao Mingfei; Liu Peng [Lanzhou University, State Key Laboratory of Applied Organic Chemistry and Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering (China)], E-mail: pliu@lzu.edu.cn

2008-05-15

Halloysite nanotubes (HNTs) grafted hyperbranched polymers were prepared by the self-condensing vinyl polymerization (SCVP) of 2-((bromoacetyl)oxy)ethyl acrylate (BAEA) and the self-condensing vinyl copolymerization of n-butyl acrylate (BA) and BAEA with BAEA as inimer (AB*) respectively, from the surfaces of the 2-bromoisobutyric acid modified halloysite nanotubes (HNTs-Br) via atom transfer radical polymerization (ATRP) technique. The halloysite nanotubes grafted hyperbranched polymer (HNTs-HP) and the halloysite nanotubes grafted hyperbranched copolymer (HNTs-HCP) were characterized by elemental analysis (EA), Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), and transmission electron microscope (TEM). The grafted hyperbranched polymers were characterized with Nuclear magnetic resonance (NMR) and the molecular ratio between the inimer AB* and BA in the grafted hyperbranched copolymers was found to be 3:2, calculated from the TGA and EA results.

Angiosarcoma of the liver and other occupational diseases in vinyl chloride workers

International Nuclear Information System (INIS)

Halama, J.; Becker-Stone, S.; Halama, J.M.

1985-01-01

Occupational diseases resulting from exposure to vinyl chloride (VC) include angiosarcoma of the liver and other neoplasms. Among workers exposed to VC we have found capillary abnormalities in the extremities, with scleroderma and Raynaud syndrome, acro-osteolysis, neurological and psychiatric diseases and chromosome abnormalities, as well as abnormal liver metabolism and haematological findings.(orig.)

Additive effects on phase transition and interactions in poly(vinyl methyl ether) solutions

Czech Academy of Sciences Publication Activity Database

Starovoytova, Larisa; Šťastná, J.; Šturcová, Adriana; Konefal, Rafal; Dybal, Jiří; Velychkivska, Nadiia; Radecki, M.; Hanyková, L.

2015-01-01

Roč. 7, č. 12 (2015), s. 2572-2583 ISSN 2073-4360 R&D Projects: GA ČR(CZ) GA13-23392S Institutional support: RVO:61389013 Keywords : additives * LCST * poly(vinyl methyl ether) Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.944, year: 2015

Hybrids of ethylene vinyl acetate with Na-montmorillonite and titania: preparation and characterization

International Nuclear Information System (INIS)

Ashfaq, M.

2010-01-01

Hybrids of Ethylene vinyl acetate (EVA) with Na-montmorillonite and titania were formed. Montmorillonite was organically modified by two different modifiers: Pyridinium ions and 4. 4-oxydianilinium ions. X-ray diffraction results revealed that Pyridinium ions increased the .interlayer spacing by 0.33 nm and 4, 4-oxydianilinium by 0.55 nm approximately. These modified organo-clays were successfully exfoliated in EVA using melt blending. These hybrids showed improvement in mechanical and thermal properties. 4, 4-oxydianilinium ions were degraded at higher temperature due to which thermal degradation was enhanced in EVA. In addition to this, EVA/titania hybrids were also prepared using sot-gel technique and modified by triethoxy vinyl silane and (3-aminopropyI)- triethoxy silane to increase their compatibility with EVA. Some portion of unmodified titania was heat treated to 600 degree C to obtain particulate titania. The hybrid of particulate titania and modified titania improved the mechanical properties and thermal properties. Especially in case of modified titania toughness was almost doubled. (author)

The Inhibition of Aluminum Corrosion in Sulfuric Acid by Poly(1-vinyl-3-alkyl-imidazolium Hexafluorophosphate

Directory of Open Access Journals (Sweden)

Paulina Arellanes-Lozada

2014-08-01

Full Text Available Compounds of poly(ionic liquids (PILs, derived from imidazole with different alkylic chain lengths located in the third position of the imidazolium ring (poly(1-vinyl-3-dodecyl-imidazolium (PImC12, poly(1-vinyl-3-octylimidazolium (PImC8 and poly(1-vinyl-3-butylimidazolium (PImC4 hexafluorophosphate were synthesized. These compounds were tested as corrosion inhibitors on aluminum alloy AA6061 in diluted sulfuric acid (0.1–1 M H2SO4 by weight loss tests, polarization resistance measurements and inductively coupled plasma optical emission spectroscopy. Langmuir’s isotherms suggested film formation on bare alloy while standard free energy indicated inhibition by a physisorption process. However, compound efficiencies as inhibitors ranked low (PImC12 > PImC8 > PImC4 to reach 61% for PImC12 in highly diluted acidic solution. Apparently, the high mobility of sulfates favored their adsorption in comparison to PILs. The surface film displayed general corrosion, and pitting occurred as a consequence of PILs’ partial inhibition along with a continuous dissolution of defective patchy film on formation. A slight improvement in efficiency was displayed by compounds having high molecular weight and a long alkyl chain, as a consequence of steric hindrance and PIL interactions.

THE COMPLETE, TEMPERATURE-RESOLVED EXPERIMENTAL SPECTRUM OF VINYL CYANIDE (H2CCHCN) BETWEEN 210 AND 270 GHz

International Nuclear Information System (INIS)

Fortman, Sarah M.; Neese, Christopher F.; De Lucia, Frank C.; Medvedev, Ivan R.

2011-01-01

The results of an experimental approach to the identification and characterization of the astrophysical weed vinyl cyanide in the 210-270 GHz region are reported. This approach is based on spectrally complete, intensity-calibrated spectra taken at more than 400 different temperatures in the 210-270 GHz region and is used to produce catalogs in the usual astrophysical format: line frequency, line strength, and lower state energy. As in our earlier study of ethyl cyanide, we also include the results of a frequency point-by-point analysis, which is especially well suited for characterizing weak lines and blended lines in crowded spectra. This study shows substantial incompleteness in the quantum-mechanical (QM) models used to calculate astrophysical catalogs, primarily due to their omission of many low-lying vibrational states of vinyl cyanide, but also due to the exclusion of perturbed rotational transitions. Unlike ethyl cyanide, the QM catalogs for vinyl cyanide include analyses of perturbed excited vibrational states, whose modeling is more challenging. Accordingly, we include an empirical study of the frequency accuracy of these QM models. We observe modest frequency differences for some vibrationally excited lines.

Characterization of plasma-polymerized 4-vinyl pyridine with silver nanoparticies on poly(ethylene terephthalate) film for anti-microbial properties

DEFF Research Database (Denmark)

Jiang, J.; Winther-Jensen, Bjørn; Kjær, Erik Michael

2006-01-01

scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Different thicknesses Of poly(4-vinyl pyridine) coating under different plasma polymerization conditions were studied. Silver nanoparticles with diameter around 50nm deposit were precipitated...... on the poly(4-vinyl pyridine) coating by UV irradiation in Silver nitride water solution, in order to enhance the anti-microbial properties. Different kinds of modified PET films were tested for anti-microbial properties against yeast (Debaryomyces hansenii) by using microbiological analyser mu-4200...

Water-induced phase separation of miconazole-poly (vinylpyrrolidone-co-vinyl acetate) amorphous solid dispersions: Insights with confocal fluorescence microscopy.

Science.gov (United States)

Saboo, Sugandha; Taylor, Lynne S

2017-08-30

The aim of this study was to evaluate the utility of confocal fluorescence microscopy (CFM) to study the water-induced phase separation of miconazole-poly (vinylpyrrolidone-co-vinyl acetate) (mico-PVPVA) amorphous solid dispersions (ASDs), induced during preparation, upon storage at high relative humidity (RH) and during dissolution. Different fluorescent dyes were added to drug-polymer films and the location of the dyes was evaluated using CFM. Orthogonal techniques, in particular atomic force microscopy (AFM) coupled with nanoscale infrared spectroscopy (AFM-nanoIR), were used to provide additional analysis of the drug-polymer blends. The initial miscibility of mico-PVPVA ASDs prepared under low humidity conditions was confirmed by AFM-nanoIR. CFM enabled rapid identification of drug-rich and polymer-rich phases in phase separated films prepared under high humidity conditions. The identity of drug- and polymer-rich domains was confirmed using AFM-nanoIR imaging and localized IR spectroscopy, together with Lorentz contact resonance (LCR) measurements. The CFM technique was then utilized successfully to further investigate phase separation in mico-PVPVA films exposed to high RH storage and to visualize phase separation dynamics following film immersion in buffer. CFM is thus a promising new approach to study the phase behavior of ASDs, utilizing drug and polymer specific dyes to visualize the evolution of heterogeneity in films exposed to water. Copyright © 2017 Elsevier B.V. All rights reserved.

[1+1+3] Annulation of Diazoenals and Vinyl Azides: Direct Synthesis of Functionalized 1-Pyrrolines through Olefination.

Science.gov (United States)

Kanchupalli, Vinaykumar; Katukojvala, Sreenivas

2018-05-04

A dirhodium carboxylate catalyzed [1+1+3] annulation reaction of diazoenals and vinyl azides that gives synthetically important enal-functionalized 1-pyrroline derivatives was developed. The reaction involves a novel rhodium-catalyzed olefination of diazoenals with vinyl azides via electrophilic enal carbenoids, resulting in a new class of enal acrylates. The annulation reaction was used for the direct synthesis of valuable deuterated 1-pyrrolines. Structural diversification of the enal-functionalized 1-pyrrolines resulted in the biologically important pyrrolidine-fused oxaziridine, amino acid derivatives, and a 6-azabicyclo[3.2.1]octane motif present in polycyclic alkaloids. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of Kenaf Loading on Processability and Properties of Linear Low-Density Polyethylene/Poly (Vinyl Alcohol/Kenaf Composites

Directory of Open Access Journals (Sweden)

Ai Ling Pang

2015-09-01

Full Text Available This study was conducted to evaluate the possibility of utilizing kenaf (KNF in LLDPE/PVOH to develop a new thermoplastic composite. The effect of KNF loading on the processability and mechanical, thermal and water absorption properties of linear low-density polyethylene/poly (vinyl alcohol/kenaf (LLDPE/PVOH/KNF composites were investigated. Composites with different KNF loadings (0, 10, 20, 30, and 40 phr were prepared using a Thermo Haake Polydrive internal mixer at a temperature of 150 °C and rotor speed of 50 rpm for 10 min. The results indicate that the stabilization torque, tensile modulus, water uptake, and thermal stability increased, while tensile strength and elongation at break decreased with increasing filler loading. The tensile fractured surfaces observed by scanning electron microscopy (SEM supported the deterioration in tensile properties of the LLDPE/PVOH/KNF composites with increasing KNF loading.

Preparation of various hydrogels based on poly (Vinyl pyrrolidone) and poly ethylene glycol using gamma and electron irradiation

International Nuclear Information System (INIS)

Ajji, Z.

2006-11-01

Different hydrogels have been prepared using gamma and electron irradiation; the hydrogels are composed of poly(vinyl pyrolidone) (PVP), poly(ethylene glycol) (PEG). The influence of some process parameters on the properties of the hydrogels has been investigated as: the gel fraction, maximum swelling, swelling kinetics, and mechanical properties. In the first part of this study, hydrogel dressings have been prepared using electron irradiation, and the dressings are composed of poly(vinyl pyrrolidone) (PVP), poly(ethylene glycol) (PEG) and agar. The gel fraction increases with increasing PVP concentration due to increased crosslink density, and decreases with increasing the PEG concentration. PEG seems to act not only as plasticizer but also to modify the gel properties as gelation% and maximum swelling. The prepared hydrogels dressings could be considered as a good barrier against microbes. In the second part, different hydrogels have been prepared based on different concentrations of poly(vinyl pyrrolidone) and using gamma irradiation. The gel fraction and maximum swelling of the hydrogels has been determined. In the third part of the study, different hydrogels have been prepared based on different concentrations of poly(vinyl pyrrolidone) and poly(ethylene glycol) (PEG) with various molecular weights, and using gamma irradiation. The gel fraction and maximum swelling of the hydrogels has been determined. The data show that PEG with low molecular weight needs a high dose for the gelation, and the presence of PVP lowers the needed gelation dose. The maximum swelling decreases with increasing irradiation dose and the PVP concentration, which is due to higher crosslinks between the polymer chains. (author)

Bio-Inspired nacre-like nanolignocellulose-poly (vinyl alcohol)-TiO2 composite with superior mechanical and photocatalytic properties.

Science.gov (United States)

Chen, Yipeng; Wang, Hanwei; Dang, Baokang; Xiong, Ye; Yao, Qiufang; Wang, Chao; Sun, Qingfeng; Jin, Chunde

2017-05-12

Nacre, the gold standard for biomimicry, provides an excellent example and guideline for assembling high-performance composites. Inspired by the layered structure and extraordinary strength and toughness of natural nacre, nacre-like nanolignocellulose/poly (vinyl alcohol)/TiO 2 composites possessed the similar layered structure of natural nacre were constructed through hot-pressing process. Poly (vinyl alcohol) and TiO 2 nanoparticles have been used as nanofillers to improve the mechanical performance and synchronously endow the superior photocatalytic activity of the composites. This research would be provided a promising candidate for the photooxidation of volatile organic compounds also combined with outstanding mechanical property.

Biaxial stress-strain behavior of chemical and physical gels of poly(vinyl alcohol)

Czech Academy of Sciences Publication Activity Database

Meissner, Bohumil; Matějka, Libor

2008-01-01

Roč. 49, č. 10 (2008), s. 2560-2567 ISSN 0032-3861 R&D Projects: GA AV ČR IAA400500701 Institutional research plan: CEZ:AV0Z40500505 Keywords : poly(vinyl alcohol) gels * pure shear behavior * constitutive equation Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.331, year: 2008

Fracture behavior of highly toughened poly(lactic acid)/ethylene-co-vinyl acetate blends

NARCIS (Netherlands)

Zeng, Q.; Feng, Y.; Wang, R.; Ma, P.

2018-01-01

Poly(lactic acid) (PLA) is brittle which restricts the range of its applications. The toughness of PLA was effectively improved in this work by incorporation of rubber grade ethylene-co-vinyl acetate (EVM). For example, the elongation at break of PLA increased by about 50 times after the addition of

Temperature-modified photonic bandgap in colloidal photonic crystals fabricated by vinyl functionalized silica spheres

International Nuclear Information System (INIS)

Deng Tiansong; Zhang Junyan; Zhu Kongtao; Zhang Qifeng; Wu Jinlei

2011-01-01

Graphical abstract: A thermal annealing procedure was described for fine modifying the photonic bandgap properties of colloidal photonic crystals, which were self-assembled from vinyl-functionalized silica spheres by a gravity sedimentation process. Highlights: → We described a thermal annealing procedure for fine modifying the photonic bandgap properties of colloidal photonic crystals. → The position of its stop band had more than 25% blue shift by annealing the sample from 60 to 600 deg. C. → The annealing temperature and the Bragg peak values have a linear relationship in the 120-440 deg. C range. → The effects provide a simple and controllable method for modifying the photonic bandgap properties of colloidal photonic crystals. - Abstract: A thermal annealing procedure for fine modifying the photonic bandgap properties of colloidal photonic crystals was described. The colloidal photonic crystals were assembled from monodisperse vinyl functionalized silica spheres by a gravity sedimentation process. The samples diffract light following Bragg's law combined with Snell's law. By annealing the sample at temperatures in the range of 60-600 deg. C, the position of its stop band shifted from 943 to 706 nm. It had more than 25% blue shift. In addition, the annealing temperature and the Bragg peak values have a linear relationship in the 120-440 deg. C range. Fourier transform infrared (FT-IR) spectra and thermo-gravimetric analysis (TGA) curves of vinyl functionalized silica spheres confirmed the above results. The effects provide a simple and controllable method for modifying the photonic bandgap properties of colloidal photonic crystals.

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...

One-Pot Catalytic Enantio- and Diastereoselective Syntheses of anti-, syn-cis-Disubstituted, and syn-Vinyl Cyclopropyl Alcohols

Science.gov (United States)

Kim, Hun Young; Salvi, Luca; Carroll, Patrick J.; Walsh, Patrick J.

2009-01-01

Highly enantio- and diastereoselective methods for the synthesis of a variety of cyclopropyl alcohols are reported. These methods represent the first one-pot approaches to syn-vinyl cyclopropyl alcohols, syn-cis-disubstituted cyclopropyl alcohols, and anti-cyclopropyl alcohols from achiral precursors. The methods begin with enantioselective C–C bond formations promoted by a MIB-based zinc catalyst to generate allylic alkoxide intermediates. The intermediates are then subjected to in situ alkoxide-directed cyclopropanation to provide cyclopropyl alcohols. In the synthesis of vinyl cyclopropyl alcohols, hydroboration of enynes is followed by transmetalation of the resulting dienylborane to zinc to provide dienylzinc reagents. Enantioselective addition to aldehydes generates the requisite dienyl zinc alkoxides, which are then subjected to in situ cyclopropanation to furnish vinyl cyclopropyl alcohols. Cyclopropanation occurs at the double bond allylic to the alkoxide. Using this method, syn-vinylcyclopropyl alcohols are obtained in 65–85% yield, 76–93% ee, and >19:1 dr. To prepare anti-cyclopropanols, enantioselective addition of alkylzinc reagents to conjugated enals provides allylic zinc alkoxides. Because direct cyclopropanation provides syn-cyclopropyl alcohols, the intermediate allylic alkoxides were treated with TMSCl/Et3N to generate intermediate silyl ethers. In situ cyclopropanation of the allylic silyl ether resulted in cyclopropanation to form the anti-cyclopropyl silyl ether. Workup with TBAF affords the anti-cyclopropyl alcohols in one-pot in 60–82% yield, 89–99% ee, and ≥10:1 dr. For the synthesis of cis-disubstituted cyclopropyl alcohols, in situ generated (Z)-vinyl zinc reagents were employed in asymmetric addition to aldehydes to generate (Z)-allylic zinc alkoxides. In situ cyclopropanation provides syn-cis-disubstituted cyclopropyl alcohols in 42–70% yield, 88–97% ee, and >19:1 dr. These one-pot procedures enable the synthesis of a

Radiation-Induced Graft Polymerization of Vinyl Monomers with Anion Groups onto MWNT Supports and Their Application as Electrogenerated Chemiluminescence (ECL Biosensors

Directory of Open Access Journals (Sweden)

Ji-Hye Park

2014-01-01

Full Text Available Vinyl polymer-grafted multiwalled carbon nanotube (MWNT supports with anion groups were prepared for use as biosensor supports by radiation-induced graft polymerization (RIGP of the vinyl monomers acryloyl diphosphoric acid (ADPA, acrylic acid (AA, sodium styrenesulfonate (NaSS, and methacrylic acid (MA onto the surface of MWNTs. The electrogenerated chemiluminescence sensors based on a glass carbon electrode (ECL-GCE and a screen printed electrode (ECL-SPE were fabricated by immobilization of Ru(bpy3 2+ complex after coating of vinyl polymer-grafted MWNT inks on the surface of the GCE and SPE without any polymer binders in order to obtain high electrogenerated chemiluminescence intensity. For detection of alcohol concentration, alcohol dehydrogenase (ADH was immobilized onto an ECL-GCE sensor prepared by poly(NaSS-g-MWNT supports. The prepared biosensor based on ADH is suitable for the detection of ethanol concentration in commercial drinks.

Synthesis of Lipophilic Antioxidants by a Lipase-B-Catalyzed Addition of Peracids to the Double Bond of 4-Vinyl-2-methoxyphenol.

Science.gov (United States)

Zago, Erika; Durand, Erwann; Barouh, Nathalie; Lecomte, Jérôme; Villeneuve, Pierre; Aouf, Chahinez

2015-10-21

4-Vinyl guaiacol (2) was lipophilized through the electrophilic addition of peracids to its vinylic double bond. Those peracids were formed in situ, by the Candida antarctica lipase-B-assisted perhydrolysis of carboxylic acids ranging from C2 to C18, in hydrogen peroxide solution. The addition of peracids with 4-8 carbons in their alkyl chains led to the formation of two regioisomers, with the prevalence of hydroxyesters bearing a primary free hydroxyl (4c-4e). This prevalence became more pronounced when peracids with longer alkyl chains (C10-C18) were used. In this case, only isomers 4f-4h were formed. The antioxidant activity of the resulting hydroxyesters was assessed by means of the conjugated autoxidizable triene (CAT) assay, and it was found out that the 4-vinyl guaiacol antioxidant activity was significantly increased by grafting alkyl chains with 2-8 carbons.

Synthesis of Poly(N-vinyl-2-pyrrolidone-co-methyl methacrylate by Maghnite-H+ a Non-toxic Catalyst

Directory of Open Access Journals (Sweden)

Mohamed Benadda

2014-10-01

Full Text Available In the present work poly (N-vinyl-2-pyrrolidone-co-methyl methacrylate copolymers were prepared successfully and cleanly by a one step process via cationic copolymerization of N-vinyl-2-pyrrolidone (NVP with methyl methacrylate (MMA, in heterogeneous phase using “Maghnite-H+” (Mag-H+ as catalyst in bulk, Maghnite is a montmorillonite sheet silicate clay exchanged with protons to produce Maghnite-H+. Temperature is varied between 20 and 80 °C. The effects of reaction temperature, amount of Mag-H+ on the yield and the intrinsic viscosity (η were investigated. A typical reaction product of poly (NVP-co- MMA was analyzed by infra red spectroscopy (FTIR and 1H-NMR, 13C-NMR spectroscopy as well as by viscosimetry. © 2014 BCREC UNDIP. All rights reservedReceived: 24th November 2013; Revised: 30th June 2014; Accepted: 8th July 2014How to Cite: Benadda, M., Ferrahi, M.I., Belbachir, M. (2014. Synthesis of Poly(N-vinyl-2-pyrrolidone-co-methyl methacrylate by Maghnite-H+ a Non-toxic Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (3: 201-206. (doi: 10.9767/bcrec.9.3.5743.201-206Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.3.5743.201-206

An Investigation of Chitosan-Grafted-Poly(vinyl alcohol as an Electrolyte Membrane

Directory of Open Access Journals (Sweden)

Panu Danwanichakul

2013-01-01

Full Text Available The membrane of chitosan-grafted-poly(vinyl alcohol/poly(vinyl alcohol (CS-g-PVA/PVA was investigated along with chitosan (CS, PVA, CS/PVA, and Nafion 117 membranes for transport properties of water and methanol, mechanical properties, and ionic conductivity. The ionic conductivity, σ, of the crosslinked CS-g-PVA/PVA membrane was about 4.37 mS cm−1 and the methanol permeability, PS, was 1.8×10−7 cm2s−1. These gave the selectivity, σ/PS, of 23.95 mS·s·cm−3 compared with 16.35 mS·s·cm−3 of Nafion 117 membrane. The conductivity of the crosslinked CS-g-PVA/PVA membrane was greater than others including Nafion 117 when the membranes were saturated with methanol solution of which concentration was greater than 20%. This fact and that the mechanical properties of the wet crosslinked CS-g-PVA/PVA membrane were comparable to those of other membranes made it a promising material to be used as an electrolyte membrane in a direct methanol fuel cell.

Action des copolymères éthylène-acétate de vinyle sur la cinétique de nucléation et de croissance des n-paraffines n milieu hydrocarbure. Effect of Vinyl Ethyleneacetate Copolymers on the Nucleation and Growth Kinetics of N-Paraffins in a Hydrocarbon Medium.

Directory of Open Access Journals (Sweden)

Petinelli J. C.

2006-11-01

Full Text Available On cherche à mettre en évidence le mode d'action des copolymères éthylène-acétate de vinyle sur la cinétique de cristallisation des n-paraffines en milieu hydro-carbure. On s'attache, notamment, à déterminer si l'efficacité de ces additifs est peu ou prou influencée par le nombre de motifs non paraffiniques contenus dans leur chaîne.On décrit deux montages expérimentaux, l'un permettant d'étudier la cinétique de nucléation, l'autre la cinétique de croissance en solution. On observe, grâce à ces deux dispositifs, que la fréquence de germination tridimensionnelle et la vitesse de croissance des n-paraffines diminuent quand la concentration d'acétate de vinyle dans la solution augmente.On établit une relation entre le taux d'acétate de vinyle de la chaîne des copo-lymères et leur efficacité à retarder la cinétique de nucléation. La cinétique de croissance est discutée. On montre l'adsorption très forte de ces additifs sur les faces des cristaux et que le copolymère le plus riche en groupes acétate de vinyle est celui qui retarde le plus la cinétique de nucléation et de croissance des n- paraffines. An effort is made ta détermine how vinyl ethyleneacetate copolymers effect thé crystallization kinetics of n-paraffins in a hydrocarbon medium. In particular, research was done ta see if thé effectiveness of such additives is in thé least bit influenced by thé number of non-paraffinic patterns contained in their chain.Two expérimental assemblies are described, one for investigating nucléation kinetics, thé other growth kinetics in solution. These two devices are used ta observe thot thé theee-dimensional germination fréquency and growth rate of n-paraffins decrease as thé vinyl-acétate concentration in thé solution increases.A relationship is established between thé vinyl-acétate ratio of thé copolymer chain and thé effectiveness of thé copolymer in delaying thé nucléation kinetics. Growth kinetics

Simultaneous FT-NIR and ESR analysis to study of the kinetics of photo induced polymerization of vinyl radical polymers

International Nuclear Information System (INIS)

Le, T.T.; Hill, D.J.T.; Pomery, P.J.

2000-01-01

Full text:The rate parameters for free vinyl radical polymerizations are difficult to determine accurately over the whole range of conversion. For systems which polymerize rapidly and for networks, this is a particular problem, because small differences in polymerization conditions, e.g., temperature, initiator concentration, photon flux, etc., can cause a large change in the time evolution of the concentration of carbon double bonds and radicals if these are monitored in separate experiments. The IUPAC Working Party on the Modeling of kinetics and processes of polymerization has the role of recommending the 'best' values for the kinetic parameters, using pulsed-laser polymerization (PLP) in conjunction with molar mass distribution (MMD) to determine k p as a function of temperature (T deg C) for bulk free-radical polymerization of methyl methacrylate at low conversions and ambient temperature. The vinyl radical polymers used in this study were methyl methacrylate and ethylene glycol dimethacrylate. In the past kinetic studies of vinyl photo-polymerization required the time dependence of the monomer and radical concentrations to be monitored separately by using FT-NIR spectroscopy and ESR spectroscopy, respectively. For the systems which polymerize rapidly, small differences in the conditions for two measurements, e.g. temperature and light intensity, can introduce significant errors. Hyphenated experiments involving in-situ ESR and FT-NIR spectroscopies using fibre optic, can overcome these problems. In this paper, the radical and monomer concentrations were measured under the same experimental conditions using the above techniques. The results obtained were used to evaluate the kinetic parameters for free radical vinyl polymerizations

Bioorthogonal Metabolic DNA Labelling using Vinyl Thioether-Modified Thymidine and o-Quinolinone Quinone Methide.

Science.gov (United States)

Gubu, Amu; Li, Long; Ning, Yan; Zhang, Xiaoyun; Lee, Seonghyun; Feng, Mengke; Li, Qiang; Lei, Xiaoguang; Jo, Kyubong; Tang, Xinjing

2018-04-17

Bioorthogonal metabolic DNA labeling with fluorochromes is a powerful strategy to visualize DNA molecules and their functions. Here, we report the development of a new DNA metabolic labeling strategy enabled by the catalyst-free bioorthogonal ligation using vinyl thioether modified thymidine and o-quinolinone quinone methide. With the newly designed vinyl thioether-modified thymidine (VTdT), we added labeling tags on cellular DNA, which could further be linked to fluorochromes in cells. Therefore, we successfully visualized the DNA localization within cells as well as single DNA molecules without other staining reagents. In addition, we further characterized this bioorthogonal DNA metabolic labeling using DNase I digestion, MS characterization of VTdT as well as VTdT-oQQF conjugate in cell nuclei or mitochondria. This technique provides a powerful strategy to study DNA in cells, which paves the way to achieve future spatiotemporal deciphering of DNA synthesis and functions. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanocomposites prepared from acrylonitrile butadiene rubber and organically modified montmorillonite with vinyl groups

Science.gov (United States)

Han, Mijeong; Kim, Hoonjung; Kim, Eunkyoung

2006-01-01

Nanocomposites were prepared from acrylonitrile-butadiene rubber (NBR), vinyl groups containing organically modified montmorillonite and additives, such as zinc oxide, stearic acid, and sulfur. The organically modified montmorillonites used in these nanocomposites were prepared by ion exchange reactions of N,N'-dimethylalkyl-(p-vinylbenzyl)-ammonium chlorides (DAVBAs, alkyl = octyl, dodecyl, and octadecyl) with sodium montmorillonite (Na+-MMT). NBR nanocomposites were obtained by controlling both the mixing and vulcanization conditions, by using a Brabender mixer and hot-press process. X-ray diffraction (XRD) analysis shows that, depending on the amount of montmorillonite that is added, both exfoliated and intercalated nanocomposite structures are formed. The NBR/DAVBA-MMT nanocomposites exhibit much higher mechanical properties (e.g., tensile strength, Young's modulus, 300% modulus, and hardness) as well as gas barrier properties as compared to NBR Na+-MMT or NBR composites generated from modified montmorillonites without vinyl groups. Consistent with the results of XRD, transmission electron microscopy (TEM) reveals that the intercalation and exfoliation structures of the nanocomposites coexist and that the DAVBA-MMT layers are well dispersed in NBR.

Sustainability of thermoplastic vinyl roofing membrane systems

Energy Technology Data Exchange (ETDEWEB)

Graveline, S. P. [Sika Sanarfil, Canton, (United States)

2010-07-01

The International Council for Research and Innovation in Building and Construction (CIB-RILEM) has developed a framework for sustainable roofing based on a series of tenets divided into three key areas: preservation of the environment, conservation of energy, and extended roof life. This paper investigated the sustainability of thermoplastic vinyl roof membranes using these guidelines and the relevant tenets for roof system selection. Several tenets provided alternatives for minimizing the burden on the environment using non-renewable raw materials, conserving energy with thermal insulation, and extending the lifespan of all roof components by using long lasting membranes. A life cycle assessment was carried out to provide a quantitative framework for assessing the sustainability of roofing materials. It was found that the PVC membrane systems had a lesser impact on the environment than other competing systems.

The Microwave Spectrum of Methyl Vinyl Ketone Revisited

Science.gov (United States)

Wilcox, David S.; Shirar, Amanda J.; Williams, Owen L.; Dian, Brian C.

2011-06-01

A chirped-pulse Fourier transform microwave spectrometer was used to record the rotational spectrum of methyl vinyl ketone (MVK, 3-butene-2-one) from 6 to 18.9 GHz. Two stable conformations were identified: the previously documented antiperiplanar (ap) conformer and synperiplanar (sp), which is reported for the first time in this microwave study. Methyl torsional analysis with XIAM resulted in V3 barrier heights of 433.8(1) and 376.6(2) Cm-1 for ap- and sp-MVK, respectively. Heavy atom isotopic species were detected in natural abundance allowing bond lengths and angles of the molecular frames to be calculated through Kraitchman analysis. A comparison with ab initio calculations is included.

The influence of stretching on tensile strength and solubility of poly(vinyl alcohol) fibres

NARCIS (Netherlands)

Heikens, D.; Bleijenberg, A.C.A.M.; Hoppenbrouwers, J.J.M.; Barentsen, W.M.

1971-01-01

The strength of wet-spun poly(vinyl alcohol) (pva) fibres is given as function of bath-stretching, wet-stretching and hot-stretching. In the two equations derived for strength of wet-stretching and hot-stretching the complex influence of the bath-stretching and hot-stretching is demonstrated. The

Vinyl Sulfonate/Vinyl Amide Copolymers and Different Surfactants As Suitable Systems in Eorat Higher Temperatures and Salinities Utilisation de mélanges de copolymères vinyl sulfonate/vinyl amide et de différents tensio-actifs en RAP dans des conditions de fortes salinités et de températures élevées

Directory of Open Access Journals (Sweden)

Von Halasz S. P.

2006-11-01

Full Text Available For enhanced oil recovery flooding processes there will be an increasing demand for polymers having high temperature and electrolyte stability. High molecular weight copolymers based on vinyl sulfonate, vinyl amide, and acryl amide show high performances in matching these demanding requirements. Surfactants are also known that are stable under these conditions, resulting in high deoiling rates. The aim of the present article is to demonstrate the influence of alkylphenol ethoxylates and their corresponding ether sulfonates on VS/VA/AM copolymer solutions. Aqueous solutions of such copolymers were added to varying quantities of nonionic and anionic surfactants at different temperatures using salinity scans. This article discusses the results of experiments with solutions of copolymers and surfactants in terms of compatibility, viscosity yield, flow properties, shear stability, injectability, thermostability, and oil recovery. Solutions of alkylphenol ethoxylates and/or ether sulfonates show nearly the same compatibility within a broad range of temperature and salinity, both with and without polymers. Relatively small amounts of surfactants are able to influence the EOR (Enhanced Oil Recovery properties of the polymer solutions, giving several interesting aspects for improved oil recovery. L'utilisation des polymères en récupération assistée du pétrole a fait apparaître un besoin croissant de polymères stables à haute température et à forte salinité. Les performances des terpolymères vinyl sulfonate/vinyl amide/acrylamide (VS/VA/VM ont montré que ces polymères remplissent de tels critères d'utilisation. On connaît également des tensio-actifs chimiquement stables dans ces mêmes conditions qui pourraient donc permettre d'obtenir des taux de récupération d'huile élevés. L'objectif de ce travail est de mettre en évidence l'influence de la présence d'alkylphénols éthoxyIates et des éthers sulfonates correspondants sur les

Utilization of accelerators for development of polymer materials

International Nuclear Information System (INIS)

Omichi, Hideki

1987-01-01

There are two processes in the development of polymer materials using accelerators. One is to induce graft polymerization by irradiating the electron beam of high dose rate, and another is to induce cross-linking or decomposition by irradiating on existing polymer materials. The former is mostly at the stage of research and development, while in the latter, the industrial utilization has advanced as bridged electric wires, foaming materials and thermal contraction materials. In this paper, the results of the basic research are mainly reported. The polymerization of vinyl monomers such as styrene easily advances by the irradiation of gamma ray or electron beam, accordingly, it is widely utilized as the object of basic research. When the plural radicals produced by the irradiation of polymers couple mutually or attach to double bonds, the polymer of large molecular weight arises, on the other hand, when radicals arise by the severance of main chains in polymers, the molecular weight decreases. The utilization of accelerators for the development of polymer materials is diversified. Hereafter, also particle accelerators will be used for this field. Already ion implantation, sputtering, hole-opening and so on for polymer materials began to be studied, and the new development of materials is expected. (Kako, I.)

13C n.m.r. study of solvation mechanisms in the radiation-induced polymerization of vinyl ethers

International Nuclear Information System (INIS)

Deffieux, A.; Subira, F.; Stannett, V.T.

1984-01-01

A 13 C n.m.r. study of the microstructure of ethyl vinyl ether (EVE) and isopropyl vinyl ether (IPVE) polymers prepared under various experimental conditions and using chemical or γ-ray initiation has been made. Long stereo-sequence assignments were conducted for poly EVE allowing determination of the configurational statistics of propagation in the radiation-induced polymerization of EVE in low polar solvents. Stereo-sequence intensities are found in good agreement with the Markovian model. The results are considered as further support for the occurrence of a specific interaction between the growing active centres and the polymer chains. In the case of IPVE polymers much more important overlappings of the resonance patterns are observed thus preventing any similar detailed study. (author)

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...

Mucoadhesive polymers: Synthesis and in vitro characterization of thiolated poly(vinyl alcohol).

Science.gov (United States)

Suchaoin, Wongsakorn; Pereira de Sousa, Irene; Netsomboon, Kesinee; Rohrer, Julia; Hoffmann Abad, Patricia; Laffleur, Flavia; Matuszczak, Barbara; Bernkop-Schnürch, Andreas

2016-04-30

The aim of this study was to synthesize thiolated poly(vinyl alcohol) (PVA) and to evaluate its mucoadhesive properties. Thiourea and 3-mercaptopropionic acid were utilized in order to obtain thiolated PVAs, namely, TPVA1 and TPVA2, respectively. TPVA1 and TPVA2 displayed 130.44 ± 14.99 and 958.35 ± 155.27 μmol immobilized thiol groups per gram polymer, respectively, which were then evaluated regarding reactivity of thiol groups, swelling behavior and mucoadhesive properties. Both thiolated PVAs exhibited the highest reactivity at pH 8.0 whereas more than 95% of free thiol groups were preserved at pH 5.0. Thiolation of PVA decelerated water uptake and prolonged disintegration time of test discs compared to unmodified PVA. Contact time of TPVA1- and TPVA2-based test discs on porcine intestinal mucosa was 3.2- and 15.8-fold prolonged, respectively, in comparison to non-thiolated PVA as measured by rotating cylinder method. According to tensile studies on mucosa, the total work of adhesion (TWA) and the maximum detachment force (MDF) were increased when compared to PVA. Furthermore, thiolated PVAs preserved higher percentage of viable cells compared to unmodified PVA within 24h as evaluated by MTT assay. Accordingly, thiolated PVA represents a novel excipient that can likely improve the mucoadhesive properties of various pharmaceutical formulations. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis and biological evaluation of cis-locked vinylogous combretastatin-A4 analogues: derivatives with a cyclopropyl-vinyl or a cyclopropyl-amide bridge.

Science.gov (United States)

Ty, Nancy; Kaffy, Julia; Arrault, Alban; Thoret, Sylviane; Pontikis, Renée; Dubois, Joelle; Morin-Allory, Luc; Florent, Jean-Claude

2009-03-01

A series of novel combretastatin A4 analogues, in which the cis-olefinic bridge is replaced by a cyclopropyl-vinyl or a cyclopropyl-amide moiety, were synthesized and evaluated for inhibition of tubulin polymerization and antiproliferative activity. The derivative 9a with a (cis,E)-cyclopropyl-vinyl unit is the most promising compound. As expected, molecular docking of 9a has shown that only one of the cis-cyclopropyl enantiomers is a good ligand for tubulin.

Thermoplastic starch/ethylene vinyl alcohol/forsterite nanocomposite as a candidate material for bone tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Mahdieh, Zahra [Polymeric Materials Research Group (PMRG), Department of Materials Science and Engineering, Sharif University of Technology, Tehran, P.O. Box 11155-9466 (Iran, Islamic Republic of); Bagheri, Reza, E-mail: rezabagh@sharif.edu [Polymeric Materials Research Group (PMRG), Department of Materials Science and Engineering, Sharif University of Technology, Tehran, P.O. Box 11155-9466 (Iran, Islamic Republic of); Eslami, Masoud; Amiri, Mohammad [Polymeric Materials Research Group (PMRG), Department of Materials Science and Engineering, Sharif University of Technology, Tehran, P.O. Box 11155-9466 (Iran, Islamic Republic of); Shokrgozar, Mohammad Ali; Mehrjoo, Morteza [National Cell Bank of Iran, Pasteur Institute of Iran, Tehran (Iran, Islamic Republic of)

2016-12-01

Recently, biodegradable polymers such as starch based blends have been well renowned in the biomedical field. Studies have considered them suitable for bone scaffolds, bone cements, tissue engineering scaffolds, drug delivery systems and hydrogels. The aim of this study was to synthesize nanocomposite biomaterial consisting a blend of thermoplastic starch and ethylene vinyl alcohol as the polymer matrix, and nano-structured forsterite as the ceramic reinforcing phase for bone tissue engineering applications. Furthermore, vitamin E was applied as a thermal stabilizer during melt compounding. Extrusion and injection molding were incorporated for melt blending and shaping of samples, respectively. With blending thermoplastic starch and ethylene vinyl alcohol, some properties of thermoplastic starch such as degradation rate and water absorption were modified. In addition, using nanoforsterite as the ceramic reinforcing phase resulted in the improvement of mechanical and biological traits. The addition of nanoforsterite decreased the weight loss of the thermoplastic starch and ethylene vinyl alcohol blend in simulated body fluid. Moreover, this addition modified the pH in the MTT (methyl thiazolyl tetrazolium) assay and stimulated the cell proliferation. Cell adhesion assays indicated a favorable interaction between cells and the biomaterial. The proposed nanocomposite has appropriate biocompatibility, as well as mechanical properties in order to be used in bone tissue engineering. - Highlights: • A biodegradable nanocomposite is proposed for orthopedic applications. • Vitamin E is used as an antioxidant to prevent the thermomechanical degradations. • Nanoforsterite reduced the composite degradation rate in the simulated body fluid. • Nanoforsterite modified pH in MTT assay and stimulated cell proliferation.

Thermoplastic starch/ethylene vinyl alcohol/forsterite nanocomposite as a candidate material for bone tissue engineering

International Nuclear Information System (INIS)

Mahdieh, Zahra; Bagheri, Reza; Eslami, Masoud; Amiri, Mohammad; Shokrgozar, Mohammad Ali; Mehrjoo, Morteza

2016-01-01

Recently, biodegradable polymers such as starch based blends have been well renowned in the biomedical field. Studies have considered them suitable for bone scaffolds, bone cements, tissue engineering scaffolds, drug delivery systems and hydrogels. The aim of this study was to synthesize nanocomposite biomaterial consisting a blend of thermoplastic starch and ethylene vinyl alcohol as the polymer matrix, and nano-structured forsterite as the ceramic reinforcing phase for bone tissue engineering applications. Furthermore, vitamin E was applied as a thermal stabilizer during melt compounding. Extrusion and injection molding were incorporated for melt blending and shaping of samples, respectively. With blending thermoplastic starch and ethylene vinyl alcohol, some properties of thermoplastic starch such as degradation rate and water absorption were modified. In addition, using nanoforsterite as the ceramic reinforcing phase resulted in the improvement of mechanical and biological traits. The addition of nanoforsterite decreased the weight loss of the thermoplastic starch and ethylene vinyl alcohol blend in simulated body fluid. Moreover, this addition modified the pH in the MTT (methyl thiazolyl tetrazolium) assay and stimulated the cell proliferation. Cell adhesion assays indicated a favorable interaction between cells and the biomaterial. The proposed nanocomposite has appropriate biocompatibility, as well as mechanical properties in order to be used in bone tissue engineering. - Highlights: • A biodegradable nanocomposite is proposed for orthopedic applications. • Vitamin E is used as an antioxidant to prevent the thermomechanical degradations. • Nanoforsterite reduced the composite degradation rate in the simulated body fluid. • Nanoforsterite modified pH in MTT assay and stimulated cell proliferation.

Poly(vinyl alcohol)/poly(acrylic acid)/TiO2/graphene oxide nanocomposite hydrogels for pH-sensitive photocatalytic degradation of organic pollutants

International Nuclear Information System (INIS)

Moon, Young-E; Jung, Gowun; Yun, Jumi; Kim, Hyung-Il

2013-01-01

Graphical abstract: The photocatalytic removal of pollutants was improved by the two-step mechanism based on the adsorption of pollutants by hydrogel and the effective decomposition by combination of TiO 2 and graphene oxide. -- Highlights: • pH sensitive PVA/PAAc hydrogels were prepared by radical polymerization and condensation reaction. • PVA/PAAc/TiO 2 /graphene oxide nanocomposite hydrogels were used for treatment of basic waste water. • Photocatalytic acitivity of TiO 2 was improved by incorporation of graphene oxide. • Photocatalytic decomposition by nanocomposite hydrogel was improved by increasing pH. -- Abstract: Poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 /graphene oxide nanocomposite hydrogels were prepared using radical polymerization and condensation reaction for the photocatalytic treatment of waste water. Graphene oxide was used as an additive to improve the photocatalytic activity of poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 nanocomposite hydrogels. Both TiO 2 and graphene oxide were immobilized in poly(vinyl alcohol)/poly(acrylic acid) hydrogel matrix for an easier recovery after the waste water treatment. The photocatalytic activity of poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 /graphene oxide nanocomposite hydrogels was evaluated on the base of the degradation of pollutants by using UV spectrometer. The improved removal of pollutants was due to the two-step mechanism based on the adsorption of pollutants by nanocomposite hydrogel and the effective decomposition of pollutants by TiO 2 and graphene oxide. The highest swelling of nanocomposite hydrogel was observed at pH 10 indicating that poly(vinyl alcohol)/poly(acrylic acid)/TiO 2 /graphene oxide nanocomposite hydrogels were suitable as a promising system for the treatment of basic waste water

Influence of polymer chain architecture of poly(vinyl alcohol) on the inhibition of ice recrystallization

NARCIS (Netherlands)

Olijve, L.L.C.; Hendrix, M.M.R.M.; Voets, I.K.

2016-01-01

Poly(vinyl alcohol) (PVA) is a water-soluble synthetic polymer well-known to effectively block the recrystallization of ice. The effect of polymer chain architecture on the ice recrystallization inhibition (IRI) by PVA remains unexplored. In this work, the synthesis of PVA molecular bottlebrushes is

Vinyl Acetate/butyl acrylate/acrylate Research of Ternary Soap-free Emulsion Polymerization

Directory of Open Access Journals (Sweden)

Xiao Li-guang

2016-01-01

Full Text Available Through the vinyl acetate/butyl acrylate/acrylic acrylic emulsion preparation without soap vinegar, with solid content, gel, emulsion stability and film forming properties and tensile strength as the main index to study the effect of raw materials on the properties of emulsion. Through the infrared spectrometer soap-free emulsion for microscopic analysis research. Study of the ternary soap-free vinegar acrylic emulsion with good performance.

Radiation Induced Crosslinking of Polyethylene in the Presence of Bifunctional Vinyl Monomers

DEFF Research Database (Denmark)

Joshi, M. S.; Singer, Klaus Albert Julius; Silverman, J.

1977-01-01

Several reports have been published showing that the radiation induced grafting of bifunctional vinyl monomers to low density polyethylene results in a product with an unusually high density of crosslinks. The same grafting reactions are shown to reduce the incipient gel dose by more than a factor...... of fifty. This paper is concerned with the apparent crosslinking produced by the radiation grafting of two monomers to polyethylene: acrylic acid and acrylonitrile....

Fabrication and properties of poly(polyethylene glycol n-alkyl ether vinyl ether)s as polymeric phase change materials

International Nuclear Information System (INIS)

Pei, Dong-fang; Chen, Sai; Li, Shu-qin; Shi, Hai-feng; Li, Wei; Li, Xuan; Zhang, Xing-xiang

2016-01-01

A series of poly(polyethylene glycol n-alkyl ether vinyl ether)s (PC m E n VEs) with various lengths of alkyl chains and polyethylene glycol spacers as side chain (m = 16,18; n = 1,2) were synthesized via two steps. First, monomers-ethylene glycol hexadecyl ether vinyl ether (C 16 E 1 VE), ethylene glycol octadecyl ether vinyl ether (C 18 E 1 VE), diethylene glycol hexadecyl ether vinyl ether (C 16 E 2 VE) and diethylene glycol octadecyl ether vinyl ether (C 18 E 2 VE) were synthesized by a modified Williamson etherification. Then, four new types of phase change materials were successfully fabricated by a living cationic polymerization. Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) were employed to characterize their composition, thermal properties and crystallization behavior. The results show that, the side chains of PC 16 E 1 VE, PC 18 E 1 VE, PC 16 E 2 VE and PC 18 E 2 VE are in a hexagonal lattice, and the onset temperatures for melting of PC 16 E 1 VE, PC 18 E 1 VE, PC 16 E 2 VE and PC 18 E 2 VE are 39.8 °C, 37.4 °C, 51.0 °C and 48.9 °C, the onset temperatures for crystallization are 36.7 °C, 35.2 °C, 47.4 °C and 46.3 °C, respectively. The enthalpy changes of PC 18 E 1 VE, PC 16 E 2 VE and PC 18 E 2 VE are higher than 100 J/g; on the contrary, it is 96 J/g for PC 16 E 1 VE. The enthalpy decrease is no more than 11% after 10 heating and cooling cycles. The 5 wt% mass loss temperatures of PC 18 E 1 VE, PC 16 E 2 VE and PC 18 E 2 VE are higher than 300 °C; on the contrary, it’s 283 °C for PC 16 E 1 VE. Using a weak polarity, flexible alkyl ether chain (-OCH 2 CH 2 O-) as a spacer to link the main chain and side chain is conducive to the crystallization of the alkyl side chain. These new phase change materials can be applied in heat storage, energy conservation, and environmental protection.

The influence of Poly-Vinyl-Chloride tubing on the isolated perfused rat´s heart.

NARCIS (Netherlands)

Meijler, F.L.; Durrer, D.

1950-01-01

There are types of poly-vinyl-chloride tubing sold and used for medical and biological purposes which deteriorate heart action in a few minutes. A simple method for testing P.V.C. tubing can be found in the isolated rat's he art perfused according to Langendorff.

Miscibility and Hydrogen Bonding in Blends of Poly(4-vinylphenol/Poly(vinyl methyl ketone

Directory of Open Access Journals (Sweden)

Hana Bourara

2014-10-01

Full Text Available The miscibility and phase behavior of poly(4-vinylphenol (PVPh with poly(vinyl methyl ketone (PVMK was investigated by differential scanning calorimetry (DSC, Fourier transform infrared spectroscopy (FTIR and scanning electron microscopy (SEM. It was shown that all blends of PVPh/PVMK are totally miscible. A DSC study showed the apparition of a single glass transition (Tg over their entire composition range. When the amount of PVPh exceeds 50% in blends, the obtained Tgs are found to be significantly higher than those observed for each individual component of the mixture, indicating that these blends are capable of forming interpolymer complexes. FTIR analysis revealed the existence of preferential specific interactions via hydrogen bonding between the hydroxyl and carbonyl groups, which intensified when the amount of PVPh was increased in blends. Furthermore, the quantitative FTIR study carried out for PVPh/PVMK blends was also performed for the vinylphenol (VPh and vinyl methyl ketone (VMK functional groups. These results were also established by scanning electron microscopy study (SEM.

The inhibition mechanisms of quinones and phenols present in wood for the vinyl polymerization

International Nuclear Information System (INIS)

Nobashi, Kenzo; Yokota, Tokuo

1977-01-01

The inhibitory effects and mechanisms of the quinones and phenols present in wood for the vinyl polymerization initiated with γ-rays and other initiation systems were investigated. The results obtained are summarized as follows; (1) Although phenolic compounds like isotaxiresinol inhibit the γ-ray initiated polymerization of methyl methacrylate (MMA) under the presence of air, they have no inhibitory effects in vacuo. On the other hand, o-benzoquinone and mansonones show strong inhibitory or retarding effects in vacuo. These facts indicate that oxygen may be important for the phenols to inhibit the vinyl polymerization. (2) It is shown qualitatively that there is a relationship between the strength of inhibitory action of quinones and their normal redox potentials. (3) PMMA produced under the presence of o-benzoquinone is found to include the fraction having extremely large chain length based on gel permeation chromatogram. (4) Based on the reaction products of orthoquinones and azobisisobutyronitrile, which was assumed as a model of polymer radicals, the inhibition reaction with polymer chain radical is concluded to take place upon the oxygen atoms of the quinones. (auth.)

DIELECTRIC AND PYROELECTRIC PROPERTIES OF THE COMPOSITES OF FERROELECTRIC CERAMIC AND POLY(VINYL CHLORIDE

Directory of Open Access Journals (Sweden)

M.Olszowy

2003-01-01

Full Text Available The dielectric and pyroelectric properties of lead zirconate titanate/poly(vinyl chloride [PZT/PVC] and barium titanate/poly(vinyl chloride [BaTiO3/ PVC] composites were studied. Flexible composites were fabricated in the thin films form (200-400 μm by hot-pressed method. Powders of PZT or BaTiO3 in the shape of ≤ 75 μm ceramics particles were dispersed in a PVC matrix, providing composites with 0-3} connectivity. Distribution of the ceramic particles in the polymer phase was examined by scanning electron microscopy. The analysis of the thermally stimulated currents (TSC have also been done. The changes of dielectric and pyroelectric data on composites with different contents of ceramics up to 40% volume were investigated. The dielectric constants were measured in the frequency range from 600 Hz to 6 MHz at room temperature. The pyroelectric coefficient for BaTiO3/PVC composite at 343 K is about 35 μC/m2K which is higher than that of β-PVDF (10 μC/m2 K.

Facile preparation of layered double hydroxide/MoS{sub 2}/poly(vinyl alcohol) composites

Energy Technology Data Exchange (ETDEWEB)

Zhou, Keqing, E-mail: zhoukq@cug.edu.cn [Faculty of Engineering, China University of Geosciences (Wuhan), 388 Lumo Road, Wuhan, Hubei, 430074 (China); Hu, Yixin [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Liu, Jiajia [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026 (China); Gui, Zhou, E-mail: zgui@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026 (China); Jiang, Saihua [School of Mechanical and Automotive Engineering, South China University of Technology, Wushan Road 381, Guangzhou, 510641 (China); Tang, Gang [School of Architecture and Civil Engineering, Anhui University of Technology, 59 Hudong Road, Ma' anshan, Anhui, 243002 (China)

2016-08-01

In present study, the layered double hydroxide/MoS{sub 2} hybrids are facilely synthesized by self-assembly of exfoliated MoS{sub 2} nanosheets and layered double hydroxide nanoplates via electrostatic interaction, with the aim of combining their physical and chemical functionalities to form a promising nanofiller for flame retardancy in polymer composites. The structure and morphology of the layered double hydroxide/MoS{sub 2} hybrids are probed by X-ray diffraction and transmission electron microscopy. Subsequently, the hybrids are incorporated into poly (vinyl alcohol) to serve as reinforcements. The flame retardant efficiency of MoS{sub 2} nanosheets in poly (vinyl alcohol) is significantly enhanced after the incorporation of layered double hydroxide nanoplates, which can be explained by the forming of a compact and uniform char during combustion. - Highlights: • The LDH/MoS{sub 2} hybrids were facilely synthesized by self-assembly method. • The flame retardant efficiency of LDH/MoS{sub 2} hybrids in PVA was significantly enhanced. • It is a promising strategy for improving the flame retardant efficiency of MoS{sub 2}.

Physicochemical characteristics of gamma irradiation crosslinked poly(vinyl alcohol)/magnetite ferrogel composite

OpenAIRE

Marinović-Cincović, Milena T.; Radosavljević, Aleksandra N.; Krstić, Jelena I.; Spasojević, Jelena P.; Bibić, Nataša M.; Mitrić, Miodrag N.; Kačarević-Popović, Zorica M.

2014-01-01

Magnetic field sensitive gels, ferrogels are new promising class of hydrogels. The coupling of hydrogels and magnetic particles has potential application in soft actuators such as artificial muscles or for hyperthermia application. Here a composite of magnetite particles (Fe3O4) and poly(vinyl alcohol) (PVA) hydrogel is developed using gamma irradiation as a crosslinking agent. PVA and Fe3O4 were chosen because of their well-established biocompatibility, ra...

Fabrication and Characterization of Electrospun Wool Keratin/Poly(vinyl alcohol) Blend Nanofibers

OpenAIRE

Shuai Li; Xu-Hong Yang

2014-01-01

Wool keratin/poly(vinyl alcohol) (PVA) blend nanofibers were fabricated using the electrospinning method in formic acid solutions with different weight ratios of keratin to PVA. The resultant blend nanofibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and tensile test. SEM images showed that the diameter of the blend nanofibers was affected by the content of keratin in blend solution...

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...

Morphological, dielectric and electric conductivity characteristics of clay-containing nanohybrids of Poly(N-Vinyl Carbazole) and Polypyrrole

CSIR Research Space (South Africa)

Haldar, I

2012-10-01

Full Text Available Poly(N-vinyl carbazole) (PNVC) and polypyrrole (PPY)-montmorillonite (MMT) clay hybrids were prepared by mechanical grinding of the respective monomers with MMT followed by subsequent standard processing methods. Fourier transform infrared...

Morphology in binary blends of poly(vinyl methyl ether) and epsilon-caprolactone-trimethylene carbonate diblock copolymer

NARCIS (Netherlands)

Luyten, MC; Bogels, EJF; vanEkenstein, GORA; tenBrinke, G; Bras, W; Komanschek, BE; Ryan, AJ

The morphology of symmetric diblock copolymer of epsilon-caprolactone (PCL) and trimethylene carbonate (PTMC), in blends with poly(vinyl methyl ether) (PVME) is investigated with (modulated) differential scanning calorimetry (d.s.c.), time resolved small angle (SAXS) and wide angle (WAXS) X-ray

Morphology in binary blends of poly(vinyl methyl ether) and ε-caprolactone-trimethylene carbonate diblock copolymer

NARCIS (Netherlands)

Luyten, M.C.; Bögels, E.J.F.; Alberda van Ekenstein, G.O.R.; Brinke, G. ten; Bras, W.; Komanschek, B.E.; Ryan, A.J.

1997-01-01

The morphology of symmetric diblock copolymer of ε-caprolactone (PCL) and trimethylene carbonate (PTMC), in blends with poly(vinyl methyl ether) (PVME) is investigated with (modulated) differential scanning calorimetry (d.s.c.), time resolved small angle (SAXS) and wide angle (WAXS) X-ray

Vinyl ester resin and process for curing same with ionizing radiation in the presence of amines

International Nuclear Information System (INIS)

Mani, I.

1975-01-01

The addition of about 1.5 to 5 weight percent of certain amines to a thermosettable mixture of an alkenyl aromatic monomer and a polymerizable vinyl ester resin reduces the dosage level of ionizing radiation required to cure the mixture. (U.S.)

Angiographic study of digital arteries in workers exposed to vinyl chloride

Energy Technology Data Exchange (ETDEWEB)

Falappa, P; Magnavita, N; Bergamaschi, A; Colavita, N

1982-05-01

Five patients exposed to vinyl chloride were studied by hand angiography and other non-invasive methods, including photoplethysmography, rheography, and thermography. Raynaud's phenomenon was present in all five subjects, while acro-osteolysis affected only one. Organic vascular lesions, such as narrowing, segmentary occlusions of digital arteries and bridge collaterals, were found in angiographic studies. Only one patient did not show clear segmentary occlusions, but his vessels were crooked and diffusely narrowed. Angiographic results appear to correlate well with the changes shown by non-invasive techniques.

Effects of Concentration of Organically Modified Nanoclay on Properties of Sulfonated Poly(vinyl alcohol Nanocomposite Membranes

Directory of Open Access Journals (Sweden)

Apiradee Sanglimsuwan

2011-01-01

Full Text Available Electrolyte nanocomposite membranes for proton exchange membrane fuel cells and direct methanol fuel cells were prepared by carrying out a sulfonation of poly(vinyl alcohol with sulfosuccinic acid and adding a type of organically modified montmorillonite (layered silicate nanoclay commercially known as Cloisite 93A. The effects of the different concentrations (0, 2, 4, 6, 8 wt. % of the organoclay in the membranes on water uptake, ion exchange capacity (IEC, proton conductivity, and methanol permeability were measured, respectively, via gravimetry, titration, impedance analysis, and gas chromatography techniques. The IEC values remained constant for all concentrations. Water uptakes and proton conductivities of the nanocomposite membranes changed with the clay content in a nonlinear fashion. While all the nanocomposite membranes had lower methanol permeability than Nafion115, the 6% concentration of Cloisite 93A in sulfonated poly(vinyl alcohol membrane displayed the greatest proton conductivity to methanol permeability ratio.

Controlling the Plasma-Polymerization Process of N-Vinyl-2-pyrrolidone

DEFF Research Database (Denmark)

Norrman, Kion; Winther-Jensen, Bjørn

2005-01-01

N-vinyl-2-pyrrolidone was plasma-polymerized on glass substrates using a pulsed AC plasma. Pulsed AC plasma produces a chemical surface structure different from that produced by conventional RF plasma; this is ascribed to the different power regimes used. A high degree of control over the structure...... of the chemical surface was obtained using pulsed AC plasma, as shown by ToF-SIMS. It is demonstrated how the experimental conditions to some extent control the chemical structure of the plasma-polymerized film, e.g., film thickness, density of post-plasma-polymerized oligomeric chains, and the density of intact...

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.

Effect of Poly(Vinyl Alcohol) Addition on the Properties of Hydrothermal Derived Calcium Phosphate Cement for Bone Filling Materials

Science.gov (United States)

Razali, N. N.; Sopyan, I.; Mel, M.; Salleh, H. M.; Rahman, M. M.; Singh, R.

2017-06-01

The effect of addition of poly(vinyl alcohol) on hydrothermal derived calcium phosphate cement has been studied. The precursors used to prepare the cement were calcium oxide (CaO) and ammonium dihydrogen phosphate (NH4H2PO4); the reaction was conducted in water at 80-100°C. To improve properties of CPC, poly(vinyl alcohol) (PVA) of 1wt% and 2wt% was added to the liquid phase of CPC and the results were compared to CPC without PVA addition. The addition of PVA was proved to bring remarkable effects on cohesion, setting time and mechanical strength of CPC which make it suitable physically for injectable bone filler applications.

Factors influencing optical 3D scanning of vinyl polysiloxane impression materials.

Science.gov (United States)

DeLong, R; Pintado, M R; Ko, C C; Hodges, J S; Douglas, W H

2001-06-01

Future growth in dental practice lies in digital imaging enhancing many chairside procedures and functions. This revolution requires the fast, accurate, and 3D digitizing of clinical records. One such clinical record is the chairside impression. This study investigated how surface angle and surface roughness affect the digitizing of vinyl polysiloxane impression materials. Seventeen vinyl polysiloxane impression materials were digitized with a white light optical digitizing system. Each sample was digitized at 3 different angles: 0 degrees, 22.5 degrees, and 45 degrees, and 2 digitizer camera f-stops. The digitized images were rendered on a computer monitor using custom software developed under NIH/NIDCR grant DE12225. All the 3D images were rotated to the 0 degrees position, cropped using Corel Photo-Paint 8 (Corel Corp, Ottawa, Ontario, Canada), then saved in the TIFF file format. The impression material area that was successfully digitized was calculated as a percentage of the total sample area, using Optimas 5.22 image processing software (Media Cybernetics, LP, Silver Spring, MD). The dependent variable was a Performance Value calculated for each material by averaging the percentage of area that digitized over the 3 angles. New samples with smooth and rough surfaces were made using the 7 impression materials with the largest Performance Values. These samples were tested as before, but with the additional angle of 60 degrees. Silky-Rock die stone (Whip Mix Corp, Louisville, KY) was used as a control. The Performance Values for the 17 impression materials ranged from 0% to 100%. The Performance Values for the 7 best materials were equivalent to the control at f/11 out to a surface angle of 45 degrees; however, only Examix impression material (GC America Inc, Alsip, IL) was equivalent to the control at f/11/\\16. At the 60 degrees surface angle with f/11/\\16, the Performance Values were 0% for all the impression materials, whereas that for the control was 90

Rhodium/Silver-Cocatalyzed Transannulation of N-Sulfonyl-1,2,3-triazoles with Vinyl Azides: Divergent Synthesis of Pyrroles and 2 H-Pyrazines.

Science.gov (United States)

Zhang, Lin; Sun, Ge; Bi, Xihe

2016-11-07

The first cyclization reaction between vinyl azides and N-sulfonyl-1,2,3-triazoles is reported. A Rh/Ag binary metal catalyst system proved to be necessary for the successful cyclization. By varying the structure of vinyl azides, such reaction allows the divergent synthesis of pyrroles and 2H-pyrazines. The cyclization reactions feature a broad substrate scope, good functional group tolerance, high reaction efficiency, and good to high product yields. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Poly(mono/diethylene glycol n-tetradecyl ether vinyl ethers with Various Molecular Weights as Phase Change Materials

Directory of Open Access Journals (Sweden)

Dongfang Pei

2018-02-01

Full Text Available At present, research on the relationship of comb-like polymer phase change material structures and their heat storage performance is scarce. Therefore, this relationship from both micro and macro perspectives will be studied in this paper. In order to achieve a high phase change enthalpy, ethylene glycol segments were introduced between the vinyl and the alkyl side chains. A series of poly(mono/diethylene glycol n-tetradecyl ether vinyl ethers (PC14EnVEs (n = 1, 2 with various molecular weights were polymerized by living cationic polymerization. The results of PC14E1VE and PC14E2VE showed that the minimum number of carbon atoms required for side-chain crystallization were 7.7 and 7.2, which were lower than that reported in the literature. The phase change enthalpy 89 J/g (for poly(mono ethylene glycol n-tetradecyl ether vinyl ethers and 86 J/g (for poly(hexadecyl acrylate were approximately equal. With the increase of molecular weight, the melting temperature, the melting enthalpy, and the initial thermal decomposition temperature of PC14E1VE changed from 27.0 to 28.0 °C, from 95 to 89 J/g, and from 264 to 287 °C, respectively. When the number average molar mass of PC14EnVEs exceeded 20,000, the enthalpy values remained basically unchanged. The introduction of the ethylene glycol chain was conducive to the crystallization of alkyl side chains.

UV recording with vinyl acetate and muicle dye film

Science.gov (United States)

Toxqui-Lopez, S.; Olivares-Pérez, A.; Santacruz-Vazquez, V.; Fuentes-Tapia, I.; Ordoñez-Padilla, J.

2015-03-01

Nowadays, there are many types of holographic recording medium some of them are photopolymer systems that generally consist of a polymeric host matrix, photopolymerizable momomer, photosensitizing dye and charge transfer agent but some of them have an undesirable feature, the toxicity of their components. Therefore, the present research study material recording, vinyl acetate is selected as polymeric matrix and natural dye from "muicle plant" is used as the photoinitiation these components are not toxic. The films are fabricated using gravity settling method at room temperature by this method, uniform films is obtained with good optical quality. To characterize the medium, been obtained when the coherent reed light (632.8 nm) was sent normally to the grating.

Effect of gamma radiation on the poly(vinyl alcohol)

International Nuclear Information System (INIS)

Terence, M.C.; Guedes, S.M.L.

2000-01-01

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)

Homogeneity characterization of ethylene-co-vinyl acetate copolymer (EVA) and hydrophobic silica nanocomposite by low field NMR

International Nuclear Information System (INIS)

Stael, Giovanni Chaves; Tavares, Maria I.B.

2005-01-01

This project proposes the characterization of a polymeric matrix composite material using nanometric scale hydrophobic silica as charge element, with the ethylene-vinyl acetate (EVA), by using the spin-lattice relaxation time measurement applying the low field NMR

Highly sensitive and ultrafast response surface acoustic wave humidity sensor based on electrospun polyaniline/poly(vinyl butyral) nanofibers

International Nuclear Information System (INIS)

Lin Qianqian; Li Yang; Yang Mujie

2012-01-01

Highlights: ► Polyanline/poly(vinyl butyral) nanofibers are prepared by electrospinning. ► Nanofiber-based SAW humidity sensor show high sensitivity and ultrafast response. ► The SAW sensor can detect very low humidity. - Abstract: Polyaniline (PANi) composite nanofibers were deposited on surface acoustic wave (SAW) resonator with a central frequency of 433 MHz to construct humidity sensors. Electrospun nanofibers of poly(methyl methacrylate), poly(vinyl pyrrolidone), poly(ethylene oxide), poly(vinylidene fluoride), poly(vinyl butyral) (PVB) were characterized by scanning electron microscopy, and humidity response of corresponding SAW humidity sensors were investigated. The results indicated that PVB was suitable as a matrix to form nanofibers with PANi by electrospinning (ES). Electrospun PANi/PVB nanofibers exhibited a core–sheath structure as revealed by transmittance electron microscopy. Effects of ES collection time on humidity response of SAW sensor based on PANi/PVB nanofibers were examined at room temperature. The composite nanofiber sensor exhibited very high sensitivity of ∼75 kHz/%RH from 20 to 90%RH, ultrafast response (1 s and 2 s for humidification and desiccation, respectively) and good sensing linearity. Furthermore, the sensor could detect humidity as low as 0.5%RH, suggesting its potentials for low humidity detection. Attempts were done to explain the attractive humidity sensing performance of the sensor by considering conductivity, hydrophilicity, viscoelasticity and morphology of the polymer composite nanofibers.

Ethylene vinyl acetate (EVA) as a new drug carrier for 3D printed medical drug delivery devices

DEFF Research Database (Denmark)

Genina, Natalja; Hollander, Jenny; Jukarainen, Harri

2016-01-01

The main purpose of this work was to investigate the printability of different grades of ethylene vinyl acetate (EVA) copolymers as new feedstock material for fused-deposition modeling (FDM™)-based 3D printing technology in fabrication of custom-made T-shaped intrauterine systems (IUS......) and subcutaneous rods (SR). The goal was to select an EVA grade with optimal properties, namely vinyl acetate content, melting index, flexural modulus, for 3D printing of implantable prototypes with the drug incorporated within the entire matrix of the medical devices. Indomethacin was used as a model drug...... affected the drug release profiles from the filaments and printed prototype products: faster release from the prototypes over 30 days in the in vitro tests. To conclude, this study indicates that certain grades of EVA were applicable feedstock material for 3D printing to produce drug-loaded implantable...

Sugar-Responsive Layer-by-Layer Film Composed of Phenylboronic Acid-Appended Insulin and Poly(vinyl alcohol).

Science.gov (United States)

Takei, Chihiro; Ohno, Yui; Seki, Tomohiro; Miki, Ryotaro; Seki, Toshinobu; Egawa, Yuya

2018-01-01

Previous studies have shown that reversible chemical bond formation between phenylboronic acid (PBA) and 1,3-diol can be utilized as the driving force for the preparation of layer-by-layer (LbL) films. The LbL films composed of a PBA-appended polymer and poly(vinyl alcohol) (PVA) disintegrated in the presence of sugar. This type of LbL films has been recognized as a promising approach for sugar-responsive drug release systems, but an issue preventing the practical application of LbL films is combining them with insulin. In this report, we have proposed a solution for this issue by using PBA-appended insulin as a component of the LbL film. We prepared two kinds of PBA-appended insulin derivatives and confirmed that they retained their hypoglycemic activity. The LbL films composed of PBA-appended insulin and PVA were successfully prepared through reversible chemical bond formation between the boronic acid moiety and the 1,3-diol of PVA. The LbL film disintegrated upon treatment with sugars. Based on the results presented herein, we discuss the suitability of the PBA moiety with respect to hypoglycemic activity, binding ability, and selectivity for D-glucose.

IR Laser-Induced Degradation of Poly(vinyl acetate): Novel Thermal Reactions in the Solid Polymers

Czech Academy of Sciences Publication Activity Database

Kupčík, Jaroslav; Blazevska-Gilev, J.; Pola, Josef

2005-01-01

Roč. 26, č. 5 (2005), s. 386-389 ISSN 1022-1336 R&D Projects: GA ČR(CZ) GA104/04/2028 Institutional research plan: CEZ:AV0Z40720504 Keywords : laser ablation * laser-induced polymers * poly(vinyl acetate) Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.126, year: 2005

Uranium Adsorbent Fibers Prepared by Atom-Transfer Radical Polymerization (ATRP) from Poly(vinyl chloride)- co -chlorinated Poly(vinyl chloride) (PVC- co -CPVC) Fiber

Energy Technology Data Exchange (ETDEWEB)

Brown, Suree; Yue, Yanfeng; Kuo, Li-Jung; Mehio, Nada; Li, Meijun; Gill, Gary; Tsouris, Costas; Mayes, Richard T.; Saito, Tomonori; Dai, Sheng

2016-04-20

The need to secure future supplies of energy attracts researchers in several countries to a vast resource of nuclear energy fuel: uranium in seawater (estimated at 4.5 billion tons in seawater). In this study, we developed effective adsorbent fibers for the recovery of uranium from seawater via atom-transfer radical polymerization (ATRP) from a poly- (vinyl chloride)-co-chlorinated poly(vinyl chloride) (PVC-co-CPVC) fiber. ATRP was employed in the surface graft polymerization of acrylonitrile (AN) and tert-butyl acrylate (tBA), precursors for uranium-interacting functional groups, from PVC-co-CPVC fiber. The [tBA]/[AN] was systematically varied to identify the optimal ratio between hydrophilic groups (from tBA) and uranyl-binding ligands (from AN). The best performing adsorbent fiber, the one with the optimal [tBA]/[AN] ratio and a high degree of grafting (1390%), demonstrated uranium adsorption capacities that are significantly greater than those of the Japan Atomic Energy Agency (JAEA) reference fiber in natural seawater tests (2.42-3.24 g/kg in 42 days of seawater exposure and 5.22 g/kg in 49 days of seawater exposure, versus 1.66 g/kg in 42 days of seawater exposure and 1.71 g/kg in 49 days of seawater exposure for JAEA). Adsorption of other metal ions from seawater and their corresponding kinetics were also studied. The grafting of alternative monomers for the recovery of uranium from seawater is now under development by this versatile technique of ATRP.

Solid-phase synthesis of isoxazoles using vinyl ethers as chameleon catches.

Science.gov (United States)

Barrett, A G; Procopiou, P A; Voigtmann, U

2001-10-04

[reaction: see text] Regioselective 1,3-dipolar cycloadditions of supported vinyl ethers R(1)C(=CH(2))O-CH(2)-polymer, prepared by the Tebbe olefination of R(1)CO(2)-CH(2)-polymer, with ethyl cyanoformate N-oxide gave supported isoxazoline derivatives. Release from the support under mild acidic conditions gave the isoxazoles ethyl 5-R(1)-isoxazole-3-carboxylates. Alternatively, further on-resin functionalization of the R(1) substituent using Suzuki coupling reactions and release from the support under acidic conditions gave more structurally diverse isoxazoles.

Process for preventing discoloration in hydrolyzed ethylene-vinyl acetate copolymers by exposure to radiation

International Nuclear Information System (INIS)

Hoyt, J.M.; Koch, K.; Williams, M. Jr.

1975-01-01

A process for the hydrolysis of a solid interpolymer of an ethylenically unsaturated hydrocarbon and a vinyl ester of a 2 to 6 carbon atom aliphatic carboxylic acid to products having a low yellowness index involves contacting of the solid interpolymer with a substantially anhydrous hydrolyzing agent and subjecting at least one of said interpolymer and said hydrolyzing agent to radiation. (U.S.)

Effect of monomer concentration on the kinetics of emulsifier-free emulsion polymerization of Vinyl Acetate and Methyl Acrylate

International Nuclear Information System (INIS)

Mohammad Beigi, H. R.

2001-01-01

The effect of monomer concentration on the kinetics of the emulsifier-free emulsion polymerization of vinyl acetate and methyl acrylate were studied. The polymerizations were carried out using potassium persulfate as the initiator. Form the electron micrographs of the resulting lattices, monodisperse PVAc and PMA lattices with particle diameters varying between 149-443 mm and 112-497 nm, respectively were processed. Uniformity of particle size indicated that nucleation of stable particle occurs early in the polymerization process. The polymerization rate was found to be proportional to the 0.88 and 1.5 power of the initial monomer concentration of vinyl acetate and methyl acrylate, respectively. Higher monomer concentration results in fewer particles and larger final particle diameter. With increasing monomer solubility in water the size of particle decreases and its distribution broadens

In situ electron microscopy of Braille microsystems: photo-actuation of ethylene vinyl acetate/carbon nanotube composites

Science.gov (United States)

Czaniková, Klaudia; Krupa, Igor; Račko, Dušan; Šmatko, Vasilij; Campo, Eva M.; Pavlova, Ewa; Omastová, Mária

2015-02-01

The development of new types of tactile displays based on the actuation of composite materials can aid the visually impaired. Micro/nano systems based on ethylene vinyl acetate (EVA) polymeric matrices enriched with multiwalled carbon nanotubes (MWCNT) can produce ensembles capable of light-induced actuation. In this report, we investigate two types of commercial EVA copolymers matrices containing 28 and 50 wt% vinyl-acetate (VA). Non-covalent modification of carbon nanotubes was achieved through a compatibilization technique that appends the pyrenenyl and cholesteryl groups on the carbon nanotubes (CNTs) surface. EVA/MWCNT nanocomposites were prepared by casting from a solution. These composites were shaped into Braille elements using molds. The deformation of the Braille element (BE) under light-emitting diode (LED) illumination was observed for the first time by in situ scanning electron microscopy (SEM). The superior actuation performance promoted by the EVA/MWCNT nanocomposites indicates that these materials will be useful in the future as light-driven micro/nano system actuators.

In situ electron microscopy of Braille microsystems: photo-actuation of ethylene vinyl acetate/carbon nanotube composites

International Nuclear Information System (INIS)

Czaniková, Klaudia; Krupa, Igor; Račko, Dušan; Omastová, Mária; Šmatko, Vasilij; Campo, Eva M; Pavlova, Ewa

2015-01-01

The development of new types of tactile displays based on the actuation of composite materials can aid the visually impaired. Micro/nano systems based on ethylene vinyl acetate (EVA) polymeric matrices enriched with multiwalled carbon nanotubes (MWCNT) can produce ensembles capable of light-induced actuation. In this report, we investigate two types of commercial EVA copolymers matrices containing 28 and 50 wt% vinyl-acetate (VA). Non-covalent modification of carbon nanotubes was achieved through a compatibilization technique that appends the pyrenenyl and cholesteryl groups on the carbon nanotubes (CNTs) surface. EVA/MWCNT nanocomposites were prepared by casting from a solution. These composites were shaped into Braille elements using molds. The deformation of the Braille element (BE) under light-emitting diode (LED) illumination was observed for the first time by in situ scanning electron microscopy (SEM). The superior actuation performance promoted by the EVA/MWCNT nanocomposites indicates that these materials will be useful in the future as light-driven micro/nano system actuators. (paper)

Fabrication of thermo-responsive cotton fabrics using poly(vinyl caprolactam-co-hydroxyethyl acrylamide) copolymer.

Science.gov (United States)

Xiao, Min; González, Edurne; Monterroza, Alexis Martell; Frey, Margaret

2017-10-15

A thermo-responsive polymer with hydrophilic to hydrophobic transition behavior, poly(vinyl caprolactam-co-hydroxyethyl acrylamide) P(VCL-co-HEAA), was prepared by copolymerization of vinyl caprolactam and N-hydroxyethyl acrylamide via free radical solution polymerization. The resulting copolymer was characterized by Fourier transform infrared spectroscopy (FTIR), 1 H nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The lower critical solution temperature (LCST) of P(VCL-co-HEAA) was determined at 34.5°C. This thermo-responsive polymer was then grafted onto cotton fabrics using 1,2,3,4-butanetetracarboxylic acid (BTCA) as crosslinker and sodium hypophosphite (SHP) as catalyst. FTIR and energy dispersive X-ray spectroscopy (EDS) studies confirmed the successful grafting reaction. The modified cotton fabric exhibited thermo-responsive behavior as evidenced by water vapor permeability measurement confirming decreased permeability at elevated temperature. This is the first demonstration that a PVCL based copolymer is grafted to cotton fabrics. This study provides a new thermo-responsive polymer for fabrication of smart cotton fabrics with thermally switchable hydrophilicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Miscibility and specific interactions in blends of poly(n-vinyl-2-pyrrolidone) and acid functional polyester resins.

NARCIS (Netherlands)

Senatore, D.; Berix, M.J.A.; Laven, J.; Benthem, van R.A.T.M.; With, de G.; Mezari, B.; Magusin, P.C.M.M.

2008-01-01

Miscibility and intermol. interactions of novel blends of poly(N-vinyl-2-pyrrolidone) (PVP) and acid functional polyester resins (APE) were studied by use of Differential Scanning Calorimetry (DSC), Attenuated Total Reflectance Fourier Transform IR (ATR-FTIR), Cross-Polarization Magic Angle Spinning

Poly(vinyl alcohol) composite films with high percent elongation prepared from amylose-fatty ammonium salt inclusion complexes

Science.gov (United States)

Amylose inclusion complexes prepared from cationic fatty ammonium salts and jet-cooked high amylose starch were combined with poly(vinyl alcohol) (PVOH) to form glycerol-plasticized films. Their tensile properties were compared with similar films prepared previously with analogous anionic fatty acid...

Poly(vinyl acetate-Based Block Copolymer/Clay Nanocomposites Prepared by In Situ Atom Transfer Radical Polymerization

Directory of Open Access Journals (Sweden)

M.A. Semsarzadeh

2009-12-01

Full Text Available Atom transfer radical polymerization of styrene (St and methyl methacrylate (MMA was performed at 90oC in the absence and presence of nanoclay (Cloisite 30B. Trichloromethyl-terminated poly(vinyl acetate telomerand CuCl/ PMDETA were used as a macroinitiator and catalyst system, respectively. The experimental results showed that the atom transfer radical polymerization of St and MMA in the absence or presence of nanoclay proceeds via a controlled/living mode. It was observed that nanoclay significantly enhances the homopolymerization rate of MMA, which was attributed to the activated conjugated C=C bond of MMA monomer via interaction between the carbonyl group of MMA monomer and the hydroxyl moiety (Al-O-H of nanoclay as well as the effect of nanoclay on the dynamic equilibrium between the active (macro radicals and dormant species.Homopolymerization rate of St (a non-coordinative monomer with nanoclay decreased slightly in the presence of nanoclay. This could be explained by insertion of a portion of macroinitiator into the clay galleries, where no sufficient St monomer exists due to the low compatibility or interaction of St monomer with nanoclay to react with the macroinitiator. The results obtained from XRD, TEM and TGA analyses were fully in agreement with the kinetic data. Structure of the poly(vinyl acetate-bpolystyrene nanocomposite was found to be a combination of stacking layers and exfoliated structures while poly(vinyl acetate-b-poly(methyl methacryale nanocomposite had an exfoliated structure. This difference in the structure of nanocomposites was attributed to the different capability of the monomers (styrene and methyl methacrylate to react with the hydroxyl moiety (Al-O-H of nanoclay.

I curse your preoccupation with your record collection: The Fall on vinyl 1978-83

OpenAIRE

Osborne, Richard

2010-01-01

This chapter is in a book that is based upon papers given at the conference Messing Up The Paintwork, Salford University, 9 May 2008, the first conference to be based on the work of the Manchester band, The Fall. My chapter is based on research that I have undertaken for my monograph on the vinyl record, which is then related to the output of the band.

Pervaporation of alcohol-toluene mixtures through polymer blend membranes of poly(acrylic acid) and poly(vinyl alcohol)

NARCIS (Netherlands)

Park, H.C.; Park, H.; Meertens, R.M.; Meertens, R.M.; Mulder, M.H.V.; Smolders, C.A.; Smolders, C.A.

1994-01-01

Homogeneous membranes were prepared by blending poly(acrylic acid) with poly(vinyl alcohol). These blend membranes were evaluated for the selective separation of alcohols from toluene by pervaporation. The flux and selectivity of the membranes were determined both as a function of the blend

Evaluation of the vinyl acetate elimination process in methanogenic sludge with oxygen

International Nuclear Information System (INIS)

Duran, U.; Monroy, O.; Rendon, B.; Gomez, J.; Ramirez, F.

2009-01-01

The vinyl acetate (AV) is a volatile toxic used in the painting manufacture, causing serious problems of contamination in grounds, air and natural bodies of water. Under methanogenic conditions the complete mineralization of the AV has not been obtained, but evidences exist suggesting that with the addition of low oxygen concentrations to methanogenic sludge the elimination of this compound is possible. In this work was studied the respiratory process of elimination of the AV methano genesis and methano genesis with oxygen (1 mg/L-d). (Author)

Effect of borax concentration on the structure of Poly(Vinyl Alcohol) gels

Science.gov (United States)

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

2012-06-01

Poly(Vinyl Alcohol) hydrogels cross-linked with varying concentrations of borax have been studied using Small-Angle Neutron Scattering and X-Ray Diffraction. The intensity of scattering increases with borax concentration from 1 mg/ml up to 2 mg/ml and falls thereafter for 4 mg/ml, increasing again for a concentration of 10 mg/ml. The mesoscopic structural changes that cause these trends in the SANS data are in keeping with the variations in the X-ray diffraction patterns pertaining to structures within the PVA chains.

Vinyl ether hydrolysis. VII. Isotope effects on catalysis by aqueous hydrofluoric acid

International Nuclear Information System (INIS)

Kresge, A.J.; Chen, H.J.; Chiang, Y.

1977-01-01

Comparison of rates of hydrolysis of three vinyl ethers catalyzed by HF in H 2 O and DF in D 2 O at 25 0 C gives primary isotope effects in the range k/sub H//k/sub D/ = 3.3 to 3.5. The unexpectedly small size of these effects may be attributed to strong, ω = 1325 to 1450 cm -1 , hydrogenic bending vibrations in the proton transfer transition states of these reactions along with the lack of compensatory bending vibrations in the diatomic proton donor

The Emulsion Polymerization of Each of Vinyl Acetate and Butyl Acrylate Monomers Using bis (2-ethylhexyl) Maleate for Improving the Physicomechanical Properties of Paints and Adhesive Films

International Nuclear Information System (INIS)

Shaffei, K.A.; Moustafa, A.B.; Hamed, A.I.

2009-01-01

Improving the water sensitivity of polyvinyl acetate PVAc films as well as pressure sensitivity, adhesion and washability of poly butyl acrylate were achieved by using bis (2-ethylhexyl) maleate (BEHM). The emulsion polymerization kinetics of vinyl acetate and butyl acrylate in presence of BEHM was studied. The order of the polymerization reaction with respect to the BEHM in presence of each of vinyl acetate and butyl acrylate was studied. The physicomechanical properties of the polyvinyl acetate films and vinyl acetate-butyl acrylate copolymer films were studied in presence of BEHM and the obtained results were matched with those prepared in the presence of pluronic F 108 and showed superior values. The obtained mean average molecular weights were found to be smaller in presence of BEHM assuring the presence of chain transfer reaction.

The Emulsion Polymerization of Each of Vinyl Acetate and Butyl Acrylate Monomers Using bis (2-ethylhexyl Maleate for Improving the Physicomechanical Properties of Paints and Adhesive Films

Directory of Open Access Journals (Sweden)

K. A. Shaffei

2009-01-01

Full Text Available Improving the water sensitivity of polyvinyl acetate PVAc films as well as pressure sensitivity, adhesion and washability of polybutyl acrylate were achieved by using bis (2-ethylhexyl maleate (BEHM. The emulsion polymerization kinetics of vinyl acetate and butyl acrylate in presence of BEHM was studied. The order of the polymerization reaction with respect to the BEHM in presence of each of vinyl acetate and butyl acrylate was studied. The physicomechanical properties of the polyvinyl acetate films and vinyl acetate-butyl acrylate copolymer films were studied in presence of BEHM and the obtained results were matched with those prepared in the presence of pluronic F 108 and showed superior values. The obtained mean average molecular weights were found to be smaller in presence of BEHM assuring the presence of chain transfer reaction.

Shape Memory Composites Based on Electrospun Poly(vinyl alcohol) Fibers and a Thermoplastic Polyether Block Amide Elastomer.

Science.gov (United States)

Shirole, Anuja; Sapkota, Janak; Foster, E Johan; Weder, Christoph

2016-03-01

The present study aimed at developing new thermally responsive shape-memory composites, that were fabricated by compacting mats of electrospun poly(vinyl alcohol) (PVA) fibers and sheets of a thermoplastic polyether block amide elastomer (PEBA). This design was based on the expectation that the combination of the rubber elasticity of the PEBA matrix and the mechanical switching exploitable through the reversible glass transition temperature (Tg) of the PVA filler could be combined to create materials that display shape memory characteristics as an emergent effect. Dynamic mechanical analyses (DMA) show that, upon introduction of 10-20% w/w PVA fibers, the room-temperature storage modulus (E') increased by a factor of 4-5 in comparison to the neat PEBA, and they reveal a stepwise reduction of E' around the Tg of PVA (85 °C). This transition could indeed be utilized to fix a temporary shape and recover the permanent shape. At low strain, the fixity was 66 ± 14% and the recovery was 98 ± 2%. Overall, the data validate a simple and practical strategy for the fabrication of shape memory composites that involves a melt compaction process and employs two commercially available polymers.

Studies on the effect of nano-TiO{sub 2} on vinyl acetate-butyl acrylate latex-based surface coating

Energy Technology Data Exchange (ETDEWEB)

Suma, K.K. [Dept. of Polymer Science and Rubber Technology, Cochin University of Science and Technology, Kochi 22, Kerala (India); Dept. of Chemistry, Maharaja' s College, Ernakulam, Kerala (India); Jacob, Sinto [Dept. of Polymer Science and Rubber Technology, Cochin University of Science and Technology, Kochi 22, Kerala (India); Joseph, Rani, E-mail: rani@cusat.ac.i [Dept. of Polymer Science and Rubber Technology, Cochin University of Science and Technology, Kochi 22, Kerala (India)

2010-04-15

Vinyl acetate-butyl acrylate (VAc-BuA) copolymer latex was prepared by emulsion polymerization. The polymerization conditions and the composition were optimized. The 85/15 wt.% (vinyl acetate/butyl acrylate) gave good tensile strength of the order of 15.6 MPa and a glass transition temperature (T{sub g}) value of -6.49 deg. C. This copolymer was used as a binder in the paint formulation. In this formulation nanosized TiO{sub 2} sol was used as a pigment instead of conventional rutile TiO{sub 2}. Nanosized TiO{sub 2} is prepared by wet process. These nanosized TiO{sub 2} rutile colloidal sol has improved properties such as photostability, UV shielding, dispersion stability, etc. The surface properties of paint were found to be superior compared to commercially used paint.

In vitro and in vivo study to the biocompatibility and biodegradation of hydroxyapatite/poly(vinyl alcohol)/gelatin composite.

NARCIS (Netherlands)

Wang, M.; Li, Y.; Wu, J.; Xu, F.; Zuo, Y.; Jansen, J.A.

2008-01-01

A novel porous composite material composed of hydroxyapatite, poly(vinyl alcohol) (PVA), and gelatin (Gel) was fabricated by emulsification. Scanning electron microscopy showed that the material had a well-interconnected porous structure including many macropores (100-500 microm) and micropores

21 CFR 700.14 - Use of vinyl chloride as an ingredient, including propellant of cosmetic aerosol products.

Science.gov (United States)

2010-04-01

... propellant of cosmetic aerosol products. 700.14 Section 700.14 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) COSMETICS GENERAL Requirements for Specific Cosmetic Products § 700.14 Use of vinyl chloride as an ingredient, including propellant of cosmetic aerosol products...

Conjugate Addition of Nucleophiles to the Vinyl Function of 2-Chloro-4-vinylpyrimidine Derivatives

Directory of Open Access Journals (Sweden)

Lucjan Strekowski

2010-03-01

Full Text Available Conjugate addition reaction of various nucleophiles across the vinyl group of 2-chloro-4-vinylpyrimidine, 2-chloro-4-(1-phenylvinylpyrimidine and 2-chloro-4-vinylquinazoline provides the corresponding 2-chloro-4-(2-substituted ethylpyrimidines and 2-chloro-4-(2-substituted ethylquinazolines. Treatment of these products, without isolation, with N-methylpiperazine results in nucleophilic displacement of chloride and yields the corresponding 2,4-disubstituted pyrimidines and quinazolines.

Electro–optical properties of poly(vinyl acetate)/polyindole composite film

International Nuclear Information System (INIS)

Bhagat, D. J.; Dhokane, G. R.; Bajaj, N. S.

2016-01-01

In present work, electrical and optical properties of poly(vinyl acetate)/polyindole (PVAc/PIN) composite film are reported. The prepared composite was characterized via X–ray diffraction (XRD), UV–Vis spectroscopy and DC conductivity measurements. The polymer chain separation was determined using XRD analysis. An attempt has been made to study the temperature dependence of DC conductivity of PVAc/PIN composite in temperature range 308–373 K. The DC conductivity initially increases and reaches to 2.45×10–7 S/cm. The optical band gap value of composite is determined as 4.77 eV. The semiconducting nature of composite observed from electronic as well as optical band gap and Arrhenius behavior of DC plot.

Electro–optical properties of poly(vinyl acetate)/polyindole composite film

Energy Technology Data Exchange (ETDEWEB)

Bhagat, D. J., E-mail: bhagatd@rediffmail.com; Dhokane, G. R. [Arts, Science and Commerce College, Chikhaldara, 444807, Maharashtra (India); Bajaj, N. S. [Toshniwal Arts, Science and Commerce College, Sengaon, Maharashtra (India)

2016-05-06

In present work, electrical and optical properties of poly(vinyl acetate)/polyindole (PVAc/PIN) composite film are reported. The prepared composite was characterized via X–ray diffraction (XRD), UV–Vis spectroscopy and DC conductivity measurements. The polymer chain separation was determined using XRD analysis. An attempt has been made to study the temperature dependence of DC conductivity of PVAc/PIN composite in temperature range 308–373 K. The DC conductivity initially increases and reaches to 2.45×10–7 S/cm. The optical band gap value of composite is determined as 4.77 eV. The semiconducting nature of composite observed from electronic as well as optical band gap and Arrhenius behavior of DC plot.

Laboratory characterization and astrophysical detection of vibrationally excited states of vinyl cyanide in Orion-KL

Science.gov (United States)

López, A.; Tercero, B.; Kisiel, Z.; Daly, A. M.; Bermúdez, C.; Calcutt, H.; Marcelino, N.; Viti, S.; Drouin, B. J.; Medvedev, I. R.; Neese, C. F.; Pszczółkowski, L.; Alonso, J. L.; Cernicharo, J.

2014-12-01

Context. We perform a laboratory characterization in the 18-1893 GHz range and astronomical detection between 80-280 GHz in Orion-KL with IRAM-30 m of CH2CHCN (vinyl cyanide) in its ground and vibrationally excited states. Aims: Our aim is to improve the understanding of rotational spectra of vibrationally excited vinyl cyanide with new laboratory data and analysis. The laboratory results allow searching for these excited state transitions in the Orion-KL line survey. Furthermore, rotational lines of CH2CHCN contribute to the understanding of the physical and chemical properties of the cloud. Methods: Laboratory measurements of CH2CHCN made on several different frequency-modulated spectrometers were combined into a single broadband 50-1900 GHz spectrum and its assignment was confirmed by Stark modulation spectra recorded in the 18-40 GHz region and by ab-initio anharmonic force field calculations. For analyzing the emission lines of vinyl cyanide detected in Orion-KL we used the excitation and radiative transfer code (MADEX) at LTE conditions. Results: Detailed characterization of laboratory spectra of CH2CHCN in nine different excited vibrational states: ν11 = 1, ν15 = 1, ν11 = 2, ν10 = 1 ⇔ (ν11 = 1,ν15 = 1), ν11 = 3/ν15 = 2/ν14 = 1, (ν11 = 1,ν10 = 1) ⇔ (ν11 = 2,ν15 = 1), ν9 = 1, (ν11 = 1,ν15 = 2) ⇔ (ν10 = 1,ν15 = 1) ⇔ (ν11 = 1,ν14 = 1), and ν11 = 4 are determined, as well as the detection of transitions in the ν11 = 2 and ν11 = 3 states for the first time in Orion-KL and of those in the ν10 = 1 ⇔ (ν11 = 1,ν15 = 1) dyad of states for the first time in space. The rotational transitions of the ground state of this molecule emerge from four cloud components of hot core nature, which trace the physical and chemical conditions of high mass star forming regions in the Orion-KL Nebula. The lowest energy vibrationally excited states of vinyl cyanide, such as ν11 = 1 (at 328.5 K), ν15 = 1 (at 478.6 K), ν11 = 2 (at 657.8 K), the ν10

Blends of ethylene-co-vinyl acetate and poly(3-hydroxybutyrate with adhesion property

Directory of Open Access Journals (Sweden)

A. de Lucas-Freile

2018-07-01

Full Text Available The structure and properties of ethylene-co-vinyl acetate (EVA and poly(3-hydroxybutyrate (PHB blends depended on their PHB content, i.e. PHB phase dominated the structure for amounts of PHB higher than 50 wt%, whereas EVA phase is dominant for PHB content lower than 50 wt%. EVA/PHB (70:30 blend showed unexpected different structure because of higher miscibility and the creation of new interfacial interactions between C=O and CH3 groups of PHB and CH3 and C=O groups of EVA, these interactions led changing of the phase structure of ethylene and vinyl acetate domains in EVA. As a consequence, improved thermal, viscoelastic and morphological properties were obtained. EVA+PHB blends containing 60 wt% or more PHB did not show tack and, interestingly, the addition of 20–30 wt% PHB enhanced the tack and displaced the maximum tack of pure EVA to lower temperature. The tack of EVA/PHB (70:30 blend was the highest among all blends because of its particular structure, fibrillation was also shown. Finally, the adhesion of EVA+PHB blends containing 20–30 wt% PHB to polypropylene (PP substrate was higher than the one of pure EVA because of the interactions between the ethylene domains in EVA phase of the blend and PP substrate surface.

Cosolvent gel-like materials from partially hydrolyzed poly(vinyl acetate)s and borax.

Science.gov (United States)

Angelova, Lora V; Terech, Pierre; Natali, Irene; Dei, Luigi; Carretti, Emiliano; Weiss, Richard G

2011-09-20

A gel-like, high-viscosity polymeric dispersion (HVPD) based on cross-linked borate, partially hydrolyzed poly(vinyl acetate) (xPVAc, where x is the percent hydrolysis) is described. Unlike hydro-HVPDs prepared from poly(vinyl alcohol) (PVA) and borate, the liquid portion of these materials can be composed of up to 75% of an organic cosolvent because of the influence of residual acetate groups on the polymer backbone. The effects of the degree of hydrolysis, molecular weight, polymer and cross-linker concentrations, and type and amount of organic cosolvent on the rheological and structural properties of the materials are investigated. The stability of the systems is explored through rheological and melting-range studies. (11)B NMR and small-angle neutron scattering (SANS) are used to probe the structure of the dispersions. The addition of an organic liquid to the xPVAc-borate HVPDs results in a drastic increase in the number of cross-linked borate species as well as the agglomeration of the polymer into bundles. These effects result in an increase in the relaxation time and thermal stability of the networks. The ability to make xPVAc-borate HVPDs with very large amounts of and rather different organic liquids, with very different rheological properties that can be controlled easily, opens new possibilities for applications of PVAc-based dispersions. © 2011 American Chemical Society

Poly(vinyl alcohol)/cellulose nanofibril hybrid aerogels with an aligned microtubular porous structure and their composites with polydimethylsiloxane

Science.gov (United States)

Tianliang Zhai; Qifeng Zheng; Zhiyong Cai; Lih-Sheng Turng; Hesheng Xia; Shaoqin Gong

2015-01-01

Superhydrophobic poly(vinyl alcohol) (PVA)/ cellulose nanofibril (CNF) aerogels with a unidirectionally aligned microtubular porous structure were prepared using a unidirectional freeze-drying process, followed by the thermal chemical vapor deposition of methyltrichlorosilane. The silanized aerogels were characterized using various techniques including scanning...

Synthesis of iron nanoparticles with poly(1-vinylpyrrolidone-co-vinyl acetate) and its application to nitrate reduction

DEFF Research Database (Denmark)

Lee, Nara; Choi, Kyunghoon; Uthuppu, Basil

2014-01-01

This study aimed to synthesize dispersed and reactive nanoscale zero-valent iron (nZVI) with poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP/VA), nontoxic and biodegradable stabilizer. The nZVI used for the experiments was prepared by reduction of ferric solution in the presence of PVP/VA with spe...

Low-temperature radiation-induced polymerization of vinyl monomers in the crystal matrix of polydimethyl siloxane

International Nuclear Information System (INIS)

Mujdinov, M.R.; Kiryukhin, D.P.; Barkalov, I.M.; Gol'danskij, V.I.

1979-01-01

It is shown that in the process of the slow cooling of vinyl monomer solution in dimethyl siloxane rubber (SKT mark) crystallization of SKT takes place, at that, considerable part of vinyl monomers (up to 70 wt. % of rubber) is sorbed in the pores of crystal matrix and it does not form its proper crystal phase. Slight anomalies in heat capacity in the 120-140 K range, the melting of non-sorbed part of MA and the melting of SKT + MA ''complex'' have been observed on the calorimetric curve at the SKT - methylacrylate (MA) system heating. In the process of heating such samples, irradiated at 77 K by γ-rays of 60 Co, heat evolution connected with sorbed monomer polarization, has been observed starting from 125-130 K. In the 140-200 K range already before MA and SKT melting intense polymerization takes place, which results in practically full monomer consumption and formation of graft copolymer. Radiation-chemical yield of monomer reduction reaches G(-M) approximately equal to 2x10 5 molecules for 100 eV, radiation yield of postpolymerization of crystal MA does not exceed G(-M) approximately equal to 50 molecules for 100 eV

Mucoadhesive hydrogel microparticles based on poly (methacrylic acid-vinyl pyrrolidone)-chitosan for oral drug delivery.

Science.gov (United States)

Sajeesh, S; Sharma, Chandra P

2011-05-01

The study was aimed at the evaluation of N-vinyl pyrrolidone (NVP) incorporated polymethacrylic acid-chitosan microparticles for oral drug delivery applications. Poly (methacrylic acid)-chitosan (PMC) and poly(methacrylic acid-vinyl pyrrolidone)-chitosan (PMVC) microparticles were prepared by an ionic-gelation method. Mucoadhesion behaviour of these particles was evaluated by ex-vivo adhesion method using freshly excised rat intestinal tissue. Cytotoxicity and absorption enhancing property of PMC and PMVC particles were evaluated on Caco 2 cell monolayers. Protease enzyme inhibition capability and insulin loading/release properties of these hydrogel particles was evaluated under in vitro experimental conditions. Addition of NVP units enhanced the mucoadhesion behavior of PMC particles on isolated rat intestinal tissue. Both PMC and PMVC particles were found non-toxic on Caco 2 cell monolayers and PMC particles was more effective in improving paracellular transport of fluorescent dextran across Caco 2 cell monolayers as compared to PMVC particles. However, protease inhibition efficacy of PMC particles was not significantly affected with NVP addition. NVP incorporation improved the insulin release properties of PMC microparticles at acidic pH. Hydrophilic modification seems to be an interesting approach in improving mucoadhesion capability of PMC microparticles.

Additional conformer observed in the microwave spectrum of methyl vinyl ketone

Science.gov (United States)

Wilcox, David S.; Shirar, Amanda J.; Williams, Owen L.; Dian, Brian C.

2011-05-01

A chirped-pulse Fourier transform microwave spectrometer was used to record the rotational spectrum of methyl vinyl ketone (MVK, 3-butene-2-one). Two stable conformations were identified: the previously documented antiperiplanar (ap) conformer and synperiplanar (sp), which is reported for the first time in this microwave study. Methyl torsional analysis resulted in V3 barrier heights of 433.8(1) and 376.6(2) cm-1 for ap- and sp-MVK, respectively. Heavy atom isotopic species of both conformers were detected in natural abundance allowing bond lengths and angles of the molecular frames to be calculated through Kraitchman analysis. A comparison with ab initio calculations is included.

Graft Copolymerization of Styrene from Poly(vinyl alcohol via RAFT Process

Directory of Open Access Journals (Sweden)

Gholam Ali Koohmareh

2011-01-01

Full Text Available Polystyrene, PS, was grafted from poly(vinyl alcohol, PVA, backbone by reversible addition-fragmentation chain transfer (RAFT polymerization. The hydroxyl groups of the PVA were converted into aromatic dithioester RAFT agent and polymerization began in the presence of this agent. The structure of compounds was confirmed by FT-IR and 1HNMR spectroscopy. The graft copolymer was characterized by thermogravimetric analysis (TGA, X-ray diffraction (XRD, and scanning electron microscopy (SEM. Grafted polystyrene chains were cleaved from the PVA backbone by acidic hydrolysis of the PVA-g-PS, and its polydispersity index, PDI, was determined by gel permeation chromatography (GPC showing narrow molecular weight distribution.

Synthesis of PbS/poly (vinyl-pyrrolidone) nanocomposite

International Nuclear Information System (INIS)

Patel, Jayesh D.; Chaudhuri, Tapas K.

2009-01-01

A simple solution growth method for synthesis of nanocomposite of PbS nanoparticles in poly(vinyl-pyrrolidone) (PVP) polymer is described. The nanocomposite is prepared from methanolic solution of lead acetate (PbAc), thiourea (TU) and PVP at room temperature (∼27 deg. C). Optical absorption spectrum of PbS/PVP nanocomposite solution shows strong absorption from 300 to 650 nm with significant bands at 400 and 590 nm which is characteristic of nanoscale PbS. Spin-coated nanocomposite films on glass have an absorption edge at ∼650 nm with band gap of 2.55 eV. Fourier transform infrared (FTIR) spectroscopy of PbS/PVP nanocomposite and PVP shows strong chemical bond between PbS nanoparticles and host PVP polymer. The transmission electron microscope (TEM) images reveal that 5-10 nm PbS particles are evenly embedded in PVP polymer. The formation of PbS is confirmed by selective area electron diffraction (SAED) of a typical nanoparticle.

Analysis of phthalate ester content in poly(vinyl chloride) plastics by means of Fourier transform Raman spectroscopy

DEFF Research Database (Denmark)

Nørbygaard, Thomas; Berg, Rolf W.

2004-01-01

Fourier transform (FT) Raman spectroscopy is applied to a range of phthalate ester plasticizers in pure form as well as in poly(vinyl chloride) (PVC) samples. It is found that phthalate esters as a group can be identified by a set of six characteristic Raman bands. FT-Raman spectra of 22 phthalate...

Hydrogels based on chemically modified poly(vinyl alcohol (PVA-GMA and PVA-GMA/chondroitin sulfate: Preparation and characterization

Directory of Open Access Journals (Sweden)

E. C. Muniz

2012-05-01

Full Text Available This work reports the preparation of hydrogels based on PVA-GMA, PVA-GMA is poly(vinyl alcohol (PVA functionalized with vinyl groups from glycidyl methacrylate (GMA, and on PVA-GMA with different content of chondroitin sulfate (CS. The degrees of swelling of PVA-GMA and PVA-GMA/CS hydrogels were evaluated in distilled water and the swelling kinetics was performed in simulated gastric and intestinal fluids (SGF and SIF. PVA-GMA and PVAGMA/CS hydrogels demonstrated to be resistant on SGF and SIF fluids. The elastic modulus, E, of swollen-hydrogels were determined through compressive tests and, according to the obtained results, the hydrogels presented good mechanical properties. At last, the presence of CS enhances the hydrogel cell compatibility as gathered by cytotoxicity assays. It was concluded that the hydrogels prepared through this work presented characteristics that allow them to be used as biomaterial, as a carrier in drug delivery system or to act as scaffolds in tissue engineering as well.

An organic dye-polymer (phenol red-poly (vinyl alcohol)) composite architecture towards tunable -optical and -saturable absorption characteristics

Energy Technology Data Exchange (ETDEWEB)

Sreedhar, Sreeja, E-mail: sreejasreedhar83@gmail.com; Muneera, C. I., E-mail: drcimuneera@hotmail.com [Department of Physics, University of Kerala, Kariavattom, Thiruvananthapuram 695581, Kerala (India); Illyaskutty, Navas [Institute for Sensorics and Information Systems (ISIS), Karlsruhe University of Applied Sciences, Moltkestr. 30, D-76133 Karlsruhe (Germany); Sreedhanya, S. [School of Chemical Sciences, M. G. University, Kottayam, Kerala 686560 (India); Philip, Reji [Light and Matter Physics Group, Raman Research Institute, Bangalore 560080 (India)

2016-05-21

Herein, we demonstrate that blending an organic dye (guest/filler), with a vinyl polymer (host template), is an inexpensive and simple approach for the fabrication of multifunctional photonic materials which could display an enhancement in the desirable properties of the constituent materials and, at the same time provide novel synergistic properties for the guest-host system. A new guest-host nanocomposite system comprising Phenol Red dye and poly (vinyl alcohol) as guest and host template, respectively, which exhibits tunable optical characteristics and saturable absorption behavior, is introduced. The dependence of local electronic environment provided by the polymer template and the interactions of the polymer molecules with the encapsulated guest molecules on the observed optical/nonlinear absorption behavior is discussed. An understanding of the tunability of the optical/ photophysical processes, with respect to the filler content, as discussed herein could help in the design of improved optical materials for several photonic device applications like organic light emitting diodes and saturable absorbers.

Inclusion polymerization of vinyl chloride monomer in deoxycholic acid host via {gamma}-ray irradiation

Energy Technology Data Exchange (ETDEWEB)

Chirachanchai, S.; Kumkrong, A. [The Petroleum and Petrochemical College, Chulalongkorn University, Bangkok (Thailand); Ishida, Hatsuo [Department of Macromolecular Science, Case Western Reserve University, Cleveland, OH (United States)

2000-03-01

Inclusion polymerization of vinyl chloride monomer (VCM) was studied in the system of 3{alpha}, 12{alpha} -dihydroxy-5{beta}-cholan-24-oic acid (deoxycholic acid, DCA). DCA-VCM inclusion compound system was originally prepared by guest intercalation technique in DCA guest free crystal. The inclusion polymerization of DCA-VCM by {gamma}-irradiation at total dose 2 Mrad, gives a syndiotactic rich polyvinyl chloride (PVC) as can be confirmed by FT-IR and FT-NMR. (author)

Inclusion polymerization of vinyl chloride monomer in deoxycholic acid host via γ-ray irradiation

International Nuclear Information System (INIS)

Chirachanchai, S.; Kumkrong, A.; Ishida, Hatsuo

2000-01-01

Inclusion polymerization of vinyl chloride monomer (VCM) was studied in the system of 3α, 12α -dihydroxy-5β-cholan-24-oic acid (deoxycholic acid, DCA). DCA-VCM inclusion compound system was originally prepared by guest intercalation technique in DCA guest free crystal. The inclusion polymerization of DCA-VCM by γ-irradiation at total dose 2 Mrad, gives a syndiotactic rich polyvinyl chloride (PVC) as can be confirmed by FT-IR and FT-NMR. (author)

Synthesis and Nrf2 Activating Ability of Thiourea and Vinyl Sulfoxide Derivatives

Energy Technology Data Exchange (ETDEWEB)

Shim, Young Sun; Hwang, Hyun Sook; Nam, Ghilsoo; Choi, Kyung Il [Korea Institute of Science and Technology, Seoul (Korea, Republic of)

2013-08-15

Thiourea and vinyl sulfoxide derivatives were designed based on the structures of sulforaphene and gallic acid, prepared and tested for HO-1 inducing activity as a measure of Nrf2 activation, and inhibitory effect on NO production as a measure of anti-inflammatory activity. Both series of compounds showed moderate activity on HO-1 induction, and no inhibitory effect on NO production. Interestingly the thiourea compound 6d showed better HO-1 induction (71% SFN) than the corresponding isothiocyanate compound 6a (55% SFN). Overall, it seemed that more efficient electrophile is needed to get more effective Nrf2 activator.

Intermolecular Dehydrative Coupling Reaction of Arylketones with Cyclic Alkenes Catalyzed by a Well-Defined Cationic Ruthenium-Hydride Complex: A Novel Ketone Olefination Method via Vinyl C–H Bond Activation

Science.gov (United States)

Yi, Chae S.; Lee, Do W.

2010-01-01

Summary The cationic ruthenium-hydride complex [(η6-C6H6)(PCy3)(CO)RuH]+BF4− was found to be a highly effective catalyst for the intermolecular olefination reaction of arylketones with cycloalkenes. The preliminary mechanistic analysis revealed that electrophilic ruthenium-vinyl complex is the key species for mediating both vinyl C–H bond activation and the dehydrative olefination steps of the coupling reaction. PMID:20567607

Studies on the Simultaneous Formation of Aroma-Active and Toxicologically Relevant Vinyl Aromatics from Free Phenolic Acids during Wheat Beer Brewing.

Science.gov (United States)

Langos, Daniel; Granvogl, Michael

2016-03-23

During the brewing process of wheat beer, the desired aroma-active vinyl aromatics 2-methoxy-4-vinylphenol and 4-vinylphenol as well as the undesired and toxicologically relevant styrene are formed from their respective precursors, free ferulic acid, p-coumaric acid, and cinnamic acid, deriving from the malts. Analysis of eight commercial wheat beers revealed high concentrations of 2-methoxy-4-vinylphenol and 4-vinylphenol always in parallel with high concentrations of styrene or low concentrations of the odorants in parallel with low styrene concentrations, suggesting a similar pathway. To better understand the formation of these vinyl aromatics, each process step of wheat beer brewing and the use of different strains of Saccharomyces cerevisiae were evaluated. During wort boiling, only a moderate decarboxylation of free phenolic acids and formation of desired and undesired vinyl aromatics were monitored due to the thermal treatment. In contrast, this reaction mainly occurred enzymatically catalyzed during fermentation with S. cerevisiae strain W68 with normal Pof(+) activity (phenolic off-flavor) resulting in a wheat beer eliciting the typical aroma requested by consumers due to high concentrations of 2-methoxy-4-vinylphenol (1790 μg/L) and 4-vinylphenol (937 μg/L). Unfortunately, also a high concentration of undesired styrene (28.3 μg/L) was observed. Using a special S. cerevisiae strain without Pof(+) activity resulted in a significant styrene reduction (beer aroma.

Crossover from Rouse dynamics to the α- relaxation in a poly(vinyl ethylene)

International Nuclear Information System (INIS)

Arbe, A.; Colmenero, J.; Richter, D.; Monkenbusch, M.; Willner, L.; Farago, B.

2004-01-01

By means of neutron spin echo (NSE) we have explored the dynamics of poly(vinyl ethylene) on length scales covering Rouse dynamics and below. The results establish the simultaneous existence of a generic sublinear diffusion regime which underlies the α-process in addition to the Rouse process. Both regimes are separated by a well- defined dynamic crossover. From that the size of the Gaussian blobs making up the Rouse model is determined directly. The glassy dynamics may thus be identified with subdiffusive motions occurring within these Gaussian blobs. (author)

Synthesis and properties of the metallo-supramolecular polymer hydrogel poly[methyl vinyl ether-alt-mono-sodium maleate]·AgNO3: Ag+/Cu2+ ion exchange and effective antibacterial activity

KAUST Repository

Xu, Feng

2014-01-01

The commercial polymeric anhydride poly(methyl vinyl ether-alt-maleic anhydride) (PVM/MA) is converted by reaction with NaOH to give poly(methyl vinyl ether-alt-mono-sodium maleate) (PVM/Na-MA). By addition of AgNO 3-solution, the formation of the silver(i) supramolecular polymer hydrogel poly[methyl vinyl ether-alt-mono-sodium maleate]·AgNO 3 is reported. Freeze-dried samples of the hydrogel show a mesoporous network of polycarboxylate ligands that are crosslinked by silver(i) cations. In the intact hydrogel, ion-exchange studies are reported and it is shown that Ag+ ions can be exchanged by copper(ii) cations without disintegration of the hydrogel. The silver(i) hydrogel shows effective antibacterial activity and potential application as burn wound dressing. © the Partner Organisations 2014.

Novel proton exchange membrane based on crosslinked poly(vinyl alcohol) for direct methanol fuel cells

Science.gov (United States)

Liu, Chien-Pan; Dai, Chi-An; Chao, Chi-Yang; Chang, Shoou-Jinn

2014-03-01

In this study, we report the synthesis and the characterization of poly (vinyl alcohol) based proton conducting membranes. In particular, we describe a novel physically and chemically PVA/HFA (poly (vinyl alcohol)/hexafluoroglutaric acid) blending membranes with BASANa (Benzenesulfonic acid sodium salt) and GA (Glutaraldehyde) as binary reaction agents. The key PEM parameters such as ion exchange capacity (IEC), water uptake, proton conductivity, and methanol permeability were controlled by adjusting the chemical composition of the membranes. The IEC value of the membrane is found to be an important parameter in affecting water uptake, conductivity as well as the permeability of the resulting membrane. Plots of the water uptake, conductivity, and methanol permeability vs. IEC of the membranes show a distinct change in the slope of their curves at roughly the same IEC value which suggests a transition of structural changes in the network. The proton conductivities and the methanol permeability of all the membranes are in the range of 10-3-10-2 S cm-1 and 10-8-10-7 cm2 s-1, respectively, depending on its binary crosslinking density, and it shows great selectivity compared with those of Nafion®-117. The membranes display good mechanical properties which suggest a good lifetime usage of the membranes applied in DMFCs.

Tailoring the morphology and properties of poly(lactic acid)/poly(ethylene-co-vinyl acetate)/starch blends via reactive compatibilization

NARCIS (Netherlands)

Ma, P.; Hristova - Bogaerds, D.G.; Schmit, P.; Goossens, J.G.P.; Lemstra, P.J.

2012-01-01

Poly(lactic acid)/poly(ethylene-co-vinyl acetate)/starch (PLA/EVA/starch) ternary blends were prepared by multi-step melt processing (reactive extrusion) in the presence of maleic anhydride (MA), benzoyl peroxide and glycerol. The effects of MA and glycerol concentration on the morphology and

Birefringence and dichroism of poly(vinyl-alcohol) foils containing phthalazinium ylids

Science.gov (United States)

Rogojanu, Alina; Dascalu, Carmen Felicia; Zelinschi, Beatrice Carmen; Caprosu, Maria; Dorohoi, Dana Ortansa

2011-10-01

Pure and colored with phthalazinium ylids poly(vinyl-alcohol) (PVA) foils were stretched under gentile heating. The birefringence of the thin foils was determined with a Babinet compensator standardized for yellow radiation of a Sodium lamp. The determined birefringence of the colored PVA foils is higher than that of the pure PVA foils. This fact indicates that the phthalazinium ylids facilitate the increase in the anisotropy of the stretched foils. The visible absorption electronic band of phthalazinium ylids was used to estimate the dichroic ratio and the degree of order of the ylid molecules in the stretched PVA foils. An increase in dichroism and birefringence with the degree of stretching has been evidenced for uncolored and colored PVA foils.

Palladium-Catalyzed Decarboxylative γ-Olefination of 2,5-Cyclohexadiene-1-carboxylic Acid Derivatives with Vinyl Halides.

Science.gov (United States)

Chang, Chi-Hao; Chou, Chih-Ming

2018-04-06

This study explores a Pd-catalyzed decarboxylative Heck-type Csp 3 -Csp 2 coupling reaction of 2,5-cyclohexadiene-1-carboxylic acid derivatives with vinyl halides to provide γ-olefination products. The olefinated 1,3-cyclohexadienes can be further oxidized to produce meta-alkylated stilbene derivatives. Additionally, the conjugated diene products can also undergo a Diels-Alder reaction to produce a bicyclo[2.2.2]octadiene framework.

A photo-crosslinked poly(vinyl alcohol) hydrogel growth factor release vehicle for wound healing applications

OpenAIRE

Bourke, Sharon L.; Al-Khalili, Mohammad; Briggs, Tonye; Michniak, Bozena B.; Kohn, Joachim; Poole-Warren, Laura A.

2003-01-01

The objective of this study was to develop and evaluate a hydrogel vehicle for sustained release of growth factors for wound healing applications. Hydrogels were fabricated using ultraviolet photo-crosslinking of acrylamide-functionalized nondegradable poly(vinyl alcohol) (PVA). Protein permeability was initially assessed using trypsin inhibitor (TI), a 21 000 MW model protein drug. TI permeability was altered by changing the solids content of the gel and by adding hydrophilic PVA fillers. As...

Methyl internal rotation in the microwave spectrum of vinyl acetate.

Science.gov (United States)

Nguyen, Ha Vinh Lam; Jabri, Atef; Van, Vinh; Stahl, Wolfgang

2014-12-26

The rotational spectrum of vinyl acetate, CH3(CO)OCH═CH2, was measured using two molecular beam Fourier transform microwave spectrometers operating in the frequency range from 2 to 40 GHz. Large splittings up to 2 GHz occurred due to the internal rotation of the acetyl methyl group CH3CO with a V3 potential of 151.492(34) cm(-1), much larger than the barrier of approximately 100 cm(-1) often found in acetates. The torsional transitions were fitted using three different programs XIAM, ERHAM, and BELGI-Cs, whereby the rotational constants, centrifugal distortion constants, and the internal rotation parameters could be determined with very high accuracy. The experimental results were supported by quantum chemical calculations. For a conformational analysis, potential energy surfaces were calculated.

Data from one test "Semi-Volatile Organic Compound Small Chamber for bis (2-Ethylhexyl) phthalate in Vinyl Flooring Test 2"

Science.gov (United States)

This data was generated from a small chamber bis(2-ethylhexyl) phthalate (DEHP) emission test. It was to participate an interaboratory study of DEHP emissions from vinyl flooring in a SVOC emission chamber organized by Virginia Polytechnic Institute and State University (VT).

Transcatheter Embolization of a Renal Artery Aneurysm Using Ethylene Vinyl Alcohol Copolymer

International Nuclear Information System (INIS)

Rautio, Riitta; Haapanen, Arto

2007-01-01

Our aim was to treat a clinically silent renal artery aneurysm. The patient was a 76-year-old man with elevated prostate-specific antigen and prostata biopsies with a gradus II-III adenocarcinoma who was incidentally found to have an aneurysm in his right renal artery. We performed a successful transcatheter embolization of the aneurysm using ethylene vinyl alcohol copolymer (Onyx). To avoid migration of the liquid material into the parent artery, a balloon was inflated in the orifice of the neck of the aneurysm while the liquid was injected. Five-month follow-up computed tomography (CT) imaging confirmed total occlusion of the aneurysm

Study on dehydrochlorination of waste poly (vinyl chloride) resins by microwave irradiation

Science.gov (United States)

Moriwaki, Saburo; Qian, Qingrong; Sunohara, Satoshi; Machida, Motoi; Tatsumoto, Hideki

Waste poly (vinyl chloride: PVC) resins are experimentally dehydrochlorinated by microwave irradiation. The following unique results are obtained: (1) plasticizer in PVC resin absorbs microwave power more effectively than PVC polymer. The higher the plasticizer content in PVC resin, the higher is the dehydrochlorination reaction (2) low PVC polymer content materials such as cushion floor require high microwave irradiation power to secure a high dehydrochlorination yield, (3) calcium carbonate in PVC resin reacts with released hydrochloric acid gas and results calcium chloride during microwave irradiation, (4) additives in PVC resin strongly influence dehydrochlorination yield, (5) it is evidenced that the PVC copolymer is also dehydrochlorinated by microwave irradiation.

Triblock and pentablock terpolymers by sequential base-assisted living cationic copolymerization of functionalized vinyl ethers

KAUST Repository

Bouchekif, Hassen; Sulhami, A. I.; AlGhamdi, Rayed D.; Gnanou, Yves; Hadjichristidis, Nikolaos

2015-01-01

A series of novel, well-defined triblock (PnBVE-b-PCEVE-b-PSiDEGVE) and pentablock (PSiDEGVE-b-PCEVE-b-PnBVE-b-PCEVE-b-PSiDEGVE) terpolymers of n-butyl vinyl ether (nBVE), 2-chloroethyl vinyl ether (CEVE) and tert-butyldimethylsilyl ethylene glycol vinyl ether (SiEGVE) were synthesized by sequential base-assisted living cationic polymerization. The living character of the homopolymerization of the three VE monomers and the crossover reaction resulting in the formation of well-defined block copolymers were investigated in various solvents (toluene, dichloromethane and n-hexane) using either a monofunctional [nBVE-acetic acid adduct (nBEA), CEVE-acetic acid adduct (CEEA) and SiDEGVE-acetic acid adduct (SiDEGEA)] or a difunctional [1,4-cyclohexane-1,4-diyl bis(2-methoxyethyl acetate) (cHDMEA)] initiator. All initiators are structurally equivalent to the dormant species of the corresponding monomers in order to achieve fast initiation. The optimal conditions of polymerization were achieved in n-hexane at -20 °C, in the presence of 1 M AcOEt (base). Good control over the number average molecular weight (Mn) and the polydispersity index (PDI) was obtained only at [Et3Al2Cl3]0 = [Chain-end]0 ≤ 10 mM. 2,6-Di-tert-butylpyridine (DtBP) was used as a non-nucleophilic proton trap to suppress any protonic initiation from moisture (i.e., Et3Al2Cl3·H2O). Well-defined PnBVEn-b-PCEVEp-b-PSiDEGVEq and PSiDEGVEq-b-PCEVEp-b-PnBVEn-b-PCEVEp-b-PSiDEGVEq terpolymers with a high crossover efficiency, no PCEVE-induced physical gelation, and predictable Mn and PDI < 1.15 were synthesized successfully provided that the targeted DPCEVE/DPnBVE ratio (i.e., p/n) did not exceed 2 and 0.2, respectively. The quantitative desilylation of the PSiEGVE by n-Bu4N+F- in THF at 0 °C led to triblock and pentablock terpolymers in which the PCEVE is the central block and the polyalcohol is the outer block. The thermal properties of the synthesized materials were examined by differential scanning

Development and Applications of Fluorogenic Probes for Mercury(II) Based on Vinyl Ether Oxymercuration

OpenAIRE

Ando, Shin; Koide, Kazunori

2011-01-01

Mercury is a major threat to the environment and to human health. It is highly desirable to develop a user-friendly kit for on-site mercury detection. Such a method must be able to detect mercury below the threshold levels for drinking water, 1–2 ppb. We developed a fluorescence method based on the oxymercuration of vinyl ethers to detect mercury in dental and environmental samples. Chloride ions interfered with the oxymercuration reaction, but the addition of AgNO3 solved this problem. Fine ...

The elastoplastic response of and moisture diffusion through a vinyl ester resin-clay nanocomposite

DEFF Research Database (Denmark)

Drozdov, Aleksey D.; Christiansen, Jesper de Claville; Gupta, R.K.

2002-01-01

Experimental data are reported on the elastoplastic response of and moisture diffusion through a vinyl ester resin–montmorillonite clay nanocomposite with various amounts of filler. Two simple models are developed for the elastoplastic behavior of a nanocomposite and for the anomalous diffusion...... of penetrant molecules. Adjustable parameters in the constitutive equations are found by fitting the observations. It is revealed that some critical concentration of filler exists (about 1 wt.-%): in the sub-critical region of concentrations, molecular mobility of the host polymer strongly decreases...

Synthesis and Properties of the Metallo-Supramolecular Polymer Hydrogel Poly[methyl vinyl ether-alt-mono-sodium maleate]∙AgNO3

KAUST Repository

Al-Dossary, Mona S.

2014-05-01

Gels are a special class of materials which are composed of 3D networks of crosslinked polymer chains that encapsulate liquid/air in the matrix. They can be classified into organogels or hydrogels (organic solvent for organogel and water for hydrogel). For hydrogels that contain metallic elements in the form of ions, the term of metallo-supramolecular polymer hydrogel (MSPHG) is often used. The aim of this project is to develop a kind of new MSPHG and investigate its properties and possible applications. The commercial polymeric anhydride poly(methyl vinyl ether-alt-maleic anhydride) (PVM/MA) is converted by reaction with NaOH to give poly(methyl vinyl ether-alt-monosodium maleate) (PVM/Na-MA). By addition of AgNO3-solution, the formation of the silver(I) supramolecular polymer hydrogel poly[methyl vinyl ether-alt-mono-sodium maleate]∙AgNO3 is obtained. Freeze-dried samples of the hydrogel show a mesoporous network of polycarboxylate ligands that are crosslinked by silver(I) cations. The supercritical CO2 dried silver(I) hydrogel was characterized by FT-IR, SEM-EDAX, TEM, TGA and Physical adsorption (BET) measurements. The intact silver(I) hydrogel was characterized by cryo-SEM. In the intact hydrogel, ion-exchange studies are reported and it is shown that Ag+ ions can be exchanged by copper(II) cations without disintegration of the hydrogel. The silver(I) hydrogel shows effective antibacterial activity and potential application as burn wound dressing.

Graft copolymers of polyurethane with various vinyl monomers via radiation-induced miniemulsion polymerization: Influential factors to grafting efficiency and particle morphology

Energy Technology Data Exchange (ETDEWEB)

Wang Hua [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China); Wang Mozhen [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China)], E-mail: pstwmz@ustc.edu.cn; Ge Xuewu [CAS Key Laboratory of Soft Matter Chemistry, Department of Polymer Science and Engineering, University of Science and Technology of China (USTC), Hefei, Anhui 230026 (China)], E-mail: xwge@ustc.edu.cn

2009-02-15

Graft copolymers of polyurethane (PU) with various vinyl monomers were synthesized through a one-pot but two-step miniemulsion polymerization process. Firstly, the polycondensation of isophorone diisocyanate (IPDI) with hydroxyl-terminated polybutadiene (HTPB) had been performed in aqueous miniemulsion at 40 deg. C in order to obtain PU dispersions. Consecutively, an in-situ graft copolymerization of the vinyl monomers with the synthesized PU was initiated by {gamma}-ray radiation at room temperature. The grafting efficiency of PU with vinyl monomer (G{sub PU/monomer}) was calculated from {sup 1}H NMR spectra and the particle morphology of the final hybrid latex was observed by transmission electron microscopy (TEM). As there was no monomer transferring in miniemulsion system, homogenous hybrid particles would be synthesized provided that the monomer was miscible with PU, such as styrene. With the increase of the polarity of the monomer, the compatibility of PU with monomer decreased. G{sub PU/monomer} varied as G{sub PU/styrene}(37%)>G{sub PU/butyl} {sub acrylate} {sub (BA)}(21%)>G{sub PU/methyl} {sub methacrylate} {sub (MMA)}(12%). The proportion of homogeneous nucleation would increase as the hydrophilicity of the monomer increased. High temperature would destabilize the miniemulsion so as to result in a less grafting efficiency. Compared to the phase separation during the seeded emulsion polymerization, the miniemulsion polymerization method facilitated the preparation of homogeneous materials owing to its monomer droplet nucleation mechanism.

Synthesis Of Copoly (2-Hydroxy Ethyl Methacrylate/N-Vinyl Pirrolidone) Hydrogel By Gamma Irradiation And Immobilization Of Ametryne

International Nuclear Information System (INIS)

Erizal

2002-01-01

The synthesis of copoly (2-hydroxy ethyl methacrylate/N-vinyl pirrolidone) hydrogel has been carried out. The 2-hydroxy ethyl methacrylate (HEMA) solution with the concentrations of 40, 50, and 60 % v/v were respectively mixed with N-vinyl pirrolidone (NVP) at a concentration of 5 % v/v with composition of 4:1, homogenized, and bubbled with N 2 .The samples were irradiated by gamma rays at a doses of 5 kGy (dose rate 7.5 kGy/h). The parameters were observed the effect of time soaking (0-32 hours) and temperatures (10-60 oC ) of the hydrogels, the ability of hydrogels to absorb water, the ability of hydrogels for immobilization and released of ametryne and its effects on the kiambang growth. After evaluation, with increasing the concentration of HEMA ( NVP constant), the water absorption and the amount of ametryne released decreased, relatively. With increasing the temperature up to 60 oC and the concentrations of HEMA, the water absorption decreased. The amount of ametryne released from hydrogel affect the growth of kiambang

In vitro and ex vivo hemocompatibility of off-the-shelf modified poly(vinyl alcohol) vascular grafts

OpenAIRE

Cutiongco, Marie Francene A.; Anderson, Deirdre E. J.; Hinds, Monica T.; Yim, Evelyn K. F.

2015-01-01

Synthetic small diameter vascular grafts with mechanical properties of native arteries, resistance to thrombosis and capacity to stimulate in situ endothelialization are an unmet clinical need. Poly(vinyl alcohol) hydrogel (PVA) is an excellent candidate as a vascular graft due to its tunable mechanical properties. However, the hydrophilicity and bio-inertness of PVA prevents endothelialization in vivo. We hypothesize that the modification of PVA with biomolecules and topographies creates a h...

Preparation and characterization of poly(vinyl sulfone)- and poly(vinylidene fluoride)-based electrolytes

Energy Technology Data Exchange (ETDEWEB)

Choe, H.S.; Giaccai, J.; Alamgir, M.; Abraham, K.M. [EIC Labs., Inc., Norwood, MA (United States)

1995-10-01

A novel group of polymer electrolytes based on poly(vinyl sulfone) (PVS) and poly(vinylidene fluoride) (PVdF) polymers, plasticized with highly conductive solutions of LiClO{sub 4}, LiN(CF{sub 3}SO{sub 2}){sub 2} or LiAsF{sub 6} dissolved in ethylene carbonate, propylene carbonate, sulfolane, or mixtures thereof, was prepared via in situ photopolymerization and solution casting, respectively. The polymer electrolytes were characterized from conductivity and cyclic voltammetry data. It was found that solutions of Li salts in the vinyl sulfone monomer were highly conductive at room temperature with conductivities of 0.6 to 1.3 x 10{sup -3} {Omega}{sup -1}cm{sup -1} at 30{sup o}C, but the conductivities decreased by about 10{sup 3} times on polymerizing. Conversely, the conductivities increased by about 10{sup 2} to 10{sup 4} times on incorporating plasticizing solvents into the solid polymer electrolytes, suggesting that ionic mobility is the primary factor affecting the conductivities of solid polymer electrolytes. The highest conductivity exhibited by PVS-based electrolyte was 3.74 x 10{sup -4} {Omega}{sup -1}cm{sup -1} and that by PVdF-based electrolyte was 1.74 x 10{sup -3} {Omega}{sup -1}cm{sup -1}, at 30{sup o}C. The PVS-based electrolytes were found to be stable to oxidation up to potentials ranging between 4.5 and 4.8 V, while the stable potential limits for PVdF-based electrolytes were between 3.9 and 4.3 V vs. Li{sup +}/Li. (author)

Thermodynamics and local structure of vinyl polymer melts

International Nuclear Information System (INIS)

Yethiraj, A.; Curro, J.G.; Rajasekaran, J.J.

1995-01-01

Monte Carlo simulation results are reported for the site-site pair correlations and equation of state of model vinyl polymer melts. The molecules are freely jointed hard chains with a hard sphere side-group attached to every other backbone bead. The local structure and pressure are investigated as a function of the diameter of the side group for melt-like densities. The intramolecular correlation functions are well represented by a single chain model where excluded volume interactions are included for beads separated by four bonds or less and neglected otherwise. The intermolecular correlation functions show interesting packing effects. The side group shields the backbone beads from approaching each other, to a degree that increases with increasing diameter of the side group. The polymer reference interaction site model integral equation theory is in good agreement with the simulation results for the pair correlation functions. At fixed volume fraction, the pressure is found to be a non-monotonic function of the size of the side group. copyright 1995 American Institute of Physics

Synthesis and characterization of UV photocrosslinkable hydrogels with poly(N-vinyl-2-pyrrolidone): Determination of the network mesh size distribution

DEFF Research Database (Denmark)

Marizza, Paolo; Abrami, M.; Keller, Stephan Sylvest

2016-01-01

Hydrogels of poly(n-vinyl-2-pyrrolidone) were produced by UV irradiation of aqueous solutions of the polymer in presence of hydrogen peroxide, used as initiator. The mechanical and the nanostructural properties of the gels were characterized by a combination of experimental techniques including...

Synthesis and application of a novel environmental C26 diglycidyl ester plasticizer based on castor oil for poly(vinyl chloride)

Science.gov (United States)

In this work, for the first time, a castor oil derived diglycidyl ester plasticizer (C26-DGE) was prepared and incorporated into poly(vinyl chloride) (PVC). The chemical structure of the product was characterized by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (...

The effect of plasticiser on the properties of radiation crosslinked poly(vinyl chloride)

International Nuclear Information System (INIS)

Jamaliah Shariff; Roslin Abu Bakar

1996-01-01

A study on the effects of plasticizers in the crosslinking of poly(vinyl chloride), PVC, by an electron beam irradiation was carried out. Different types of plasticizers were used and these, with other additives, were blended with PVC in a Brabender mixer. The blended compound was the irradiated with high energy electron beam. Subsequent analysis of its properties showed that the efficiency of crosslinking was better in the presence of the adipate and trimellitate. The tensile and elongation properties were acceptable. The ageing properties of the compounds with adipate and trimellitate-type plasticizers showed encouraging results

Kinetics and mechanism of the reaction of recombination of vinyl and hydroxyl radicals

Science.gov (United States)

Knyazev, Vadim D.

2017-10-01

The recombination of the vinyl (C2H3) and the hydroxyl (OH) radicals was studied computationally using quantum chemistry and master equation/RRKM. The reaction mechanism includes the initial addition, several isomerization steps, and decomposition via seven different channels. The spectrum of products demonstrates temperature dependence in the 300-3000 K range. At low temperatures (below 1600 K), CH3 + HCO products are dominant but at elevated temperatures vinoxy radical (CH2CHO) and hydrogen atom become more important. The acetyl (CH3CO) + H products and formation of vinylidene (CH2C:) and water products are minor but non-negligible.

Effect of Filler Concentration on Thermal Stability of Vinyl Copolymer Elastomer (VCE) Composites

Energy Technology Data Exchange (ETDEWEB)

Yang, Dali [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hubbard, Kevin Mark [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Devlin, David James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Henderson, Kevin C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pacheco, Robin Montoya [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-03-06

To study the thermal stability of vinyl copolymer elastomer (VCE) in its composite form, systematic TGA characterizations were conducted in both nonisothermal and isothermal modes. The effects of filler concentration on the aging behaviors of the VCE/filler composites were investigated under nitroplasticizer (NP) environment. FTIR characterization was used to probe the structural changes in the VCE polymer before and after the thermal treatments. This study suggests that the filler concentration significantly deteriorates the thermal stability of NP at a moderate temperature (< 70 °C). The degradation of NP, in turn, accelerates the aging process of the VCE polymer in its composite form.

Pancreatic Arteriovenous Malformation Involving the Duodenum Embolized with Ethylene-Vinyl Alcohol Copolymer (Onyx)

Energy Technology Data Exchange (ETDEWEB)

Grasso, Rosario Francesco, E-mail: r.grasso@unicampus.it; Cazzato, Roberto Luigi; Luppi, Giacomo; Faiella, Eliodoro; Del Vescovo, Riccardo; Giurazza, Francesco [University ' Campus Bio-Medico of Rome' , Department of Radiology (Italy); Borzomati, Domenico; Coppola, Roberto [University ' Campus Bio-Medico of Rome' , Department of General Surgery (Italy); Beomonte Zobel, Bruno [University ' Campus Bio-Medico of Rome' , Department of Radiology (Italy)

2012-08-15

Arteriovenous malformation (AVM) of the pancreas is a rare condition. Most patients are asymptomatic or alternatively may present with a wide spectrum of symptoms. Traditionally, surgery has been considered the treatment of choice; however, alternative approaches, such as transcatheter embolization (TAE), may be proposed. We report a case of a 48-year-old man with a pancreatic head AVM, presenting with upper abdominal pain and slight anemia. The patient refused surgery and underwent TAE by means of ethylene-vinyl alcohol copolymer (EVOH). At 3 months follow-up, the patient was able to eat regularly, with no residual pain and no signs of anemia.

Effect of Reinforced Hybrid Palm Shells on Mechanical Properties of Polyurethane-Jute Woven/ Vinyl Ester Sandwich Board

International Nuclear Information System (INIS)

Cheng, T.S.; Nurul Ain Nanyan; Lan, D.N.U.; Leng, T.P.

2014-01-01

A natural fiber sandwich was constructed from palm shells/polyurethane core and jute woven/vinyl ester face sheets by the in-situ sandwich process (core and panel prepared simultaneously). The polyurethane sandwich core was reinforced by hybrid shell systems of dried palm shell (DPS) and palm kernel shell (PKS) (50P-50D, 25P-75D), and single shell system of PKS (100P) as well as 20 phr empty fruit bunch (EFB) based on hundred part of polyurethane. The sandwich face sheets are prepared by using two jute woven layers and impregnated by vinyl ester. Interlocking between DPS and polyurethane matrix was formed, which hence enhanced the mechanical properties. The interfacial adhesion between DPS, PKS, and EFB with the polyurethane binder played the important role to achieve high mechanical properties. It was found that hybrid shells exhibited high reinforcement for sandwich's performance resulting better compression (50P-50D) and flexural (25P-75D) properties. The single shell 100P showed only improvement on flexural modulus.The fracture surface morphology of sandwich under mechanical test was performed by using optical microscopy. (author)

Synthesis of enyne and aryl vinyl sulfoxides: functionalization via Pummerer rearrangement.

Science.gov (United States)

Souza, Frederico B; Shamim, Anwar; Argomedo, Luiz M Z; Pimenta, Daniel C; Stefani, Hélio A

2015-11-01

An efficient methodology for the synthesis of aryl-substituted vinyl sulfoxides through direct substitution of aryl-substituted alkynyl grignard reagents on menthyl-p-toluenesulfinate followed by Suzuki-Miyaura cross-coupling reaction has been developed. It has also been described that the reaction of alkyl-substituted and cycloalkyl-substituted alkynyl grignard reagents with menthyl-p-toluenesulfinate led to two products, i.e., alkynyl sulfoxide derivatives, as a result of substitution, and enyne sulfoxide derivatives, which resulted from substitution followed by Michael type addition. It was possible to selectively synthesize the enyne sulfoxide derivatives by changing the concentration of the grignard reagent. These alkenyl sulfoxides were transformed into the corresponding [Formula: see text]-thio aldehydes in high yields via additive Pummerer rearrangement.

Novel synthesis on poly (vinyl alcohol): characterization, complexation a biological activity

International Nuclear Information System (INIS)

El-Sawy, N.M.; Elassar, A.Z.; Al-Fulaij, O.

2002-01-01

Poly(vinyl alcohol), PVA, readily condensed with phenyl hydrazine and malononitrile in basic medium to give the hydrazone and pyran derivatives, respectively. PVA reacted with chloroacetonitrile, biuet and thiophene carbonyl chloride to give modified polymeric materials. While addition of PVA to acrylonitrile and phenyl isothiocyanate gives the ether and thiocarbamate ester derivatives, respectively. Hydroxylamine hydrochloride reacted with the modified, carbonitrile containing, polymer to give the amidoxime derivative. The amidoximated products of PVA and carbamate ester of polymeric material were complexed with CUCL2 solution. The complex materials were confirmed by using UV and ESDS measurements. The morphology of PVA and complex with CUII was observed by SEM. Biological activity of some of the prepared compounds was investigated toward bacteria and fungi

Properties of iopamidol-incorporated poly(vinyl alcohol) microparticle as an X-ray imaging flow tracer.

Science.gov (United States)

Ahn, Sungsook; Jung, Sung Yong; Lee, Jin Pyung; Lee, Sang Joon

2011-02-10

We have recently reported on poly(vinyl alcohol) microparticles containing X-ray contrast agent, iopamidol, designed as a flow tracer working in synchrotron X-ray imaging ( Biosens. Bioelectron. 2010 , 25 , 1571 ). Although iopamidol is physically encapsulated in the microparticles, it displays a great contrast enhancement and stable feasibility in in vitro human blood pool. Nonetheless, a direct relation between the absolute amount of incorporated iopamidol and the enhancement in imaging efficiency was not observed. In this study, physical properties of the designed microparticle are systematically investigated experimentally with theoretical interpretation to correlate an enhancement in X-ray imaging efficiency. The compositional ratio of X-ray contrast agent in polymeric microparticle is controlled as 1/1 and 10/1 [contrast agent/polymer microparticle (w/w)] with changed degree of cross-linkings. Flory-Huggins interaction parameter (χ), retractive force (τ) and degree of swelling of the designed polymeric microparticles are investigated. In addition, the hydrodynamic size (D(H)) and ζ-potential are evaluated in terms of environment responsiveness. The physical properties of the designed flow tracer microparticles under a given condition are observed to be strongly related with the X-ray absorption efficiency, which are also supported by the Beer-Lambert-Bouguer law. The designed microparticles are almost nontoxic with a reasonable concentration and time period, enough to be utilized as a flow tracer in various biomedical applications. This study would contribute to the basic understanding on the physical property connected with the imaging efficiency of contrast agents.

Biodegradation of chlorinated ethenes by a methane-utilizing mixed culture

International Nuclear Information System (INIS)

Fogel, M.M.; Taddeo, A.R.; Fogel, S.

1986-01-01

Chlorinated ethenes are toxic substances which are widely distributed groundwater contaminants and are persistent in the subsurface environment. Reports on the biodegradation of these compounds under anaerobic conditions which might occur naturally in groundwater show that these substances degrade very slowly, if at all. Previous attempts to degrade chlorinated ethenes aerobically have produced conflicting results. A mixed culture containing methane-utilizing bacteria was obtained by methane enrichment of a sediment sample. Biodegradation experiments carried out in sealed culture bottles with radioactively labeled trichloroethylene (TCE) showed that approximately half of the radioactive carbon had been converted to 14 CO 2 and bacterial biomass. In addition to TCE, vinyl chloride and vinylidene chloride could be degraded to products which are not volatile chlorinated substances and are therefore likely to be further degraded to CO 2 . Two other chlorinated ethenes, cis and trans-1,2-dichloroethylene, were shown to degrade to chlorinated products, which appeared to degrade further. A sixth chlorinated ethene, tetrachloroethylene, was not degraded by the methane-utilizing culture under these conditions. The biodegradation of TCE was inhibited by acetylene, a specific inhibitor of methane oxidation by methanotrophs. This observation supported the hypothesis that a methanotroph is responsible for the observed biodegradations

Microencapsulation of Epoxidized Linseed Oil Liquid Cross-Linker in Poly(N-vinyl-pyrrolidone): Optimization by a Design-of-Experiments Approach

NARCIS (Netherlands)

Senatore, D.; Laven, J.; Benthem, van R.A.T.M.; La Camera, D.; With, de G.

2010-01-01

A liquid cross-linker, epoxidized linseed oil (ELO), was encapsulated in a plastic with a high glass transition temperature (poly(N-vinyl-2-pyrrolidone); PVP). The process parameters of the spray-drying employed were optimized by a Design-of-Experiments (DoE) approach. Three factors concerning both

Electron beam irradiation impact on surface structure and wettability of ethylene-vinyl alcohol copolymer

Science.gov (United States)

El-Saftawy, A. A.; Ragheb, M. S.; Zakhary, S. G.

2018-06-01

In the present study, electron beam (EB) is utilized to tailor the surface structure and wetting behavior of ethylene-vinyl alcohol (EVOH) copolymer. The structural deformation is examined by x-ray diffractometer (XRD). The recorded patterns reveal the formation of disordered systems on the irradiated surface. Also, the surface crystallinity degree, crystallite size, and micro-strain are studied. The microstructure induced modifications of the irradiated samples are investigated by 1-dimensional proton nuclear magnetic resonance 1H NMR spectroscopic analysis. The recorded spectra showed that the hydroxyl group (O-H) absorption intensity, enhanced compared to that of methylene (-CH2) and methine (>C-H) groups. Likewise, the changes of the polymer surface chemistry are studied by Fourier transform infrared spectroscopy (FTIR) and showed that the surface polarity improved after irradiation. The contact angle method is used to prove the surface wettability improvements after irradiation. Additionally, the fucoidan-coated samples exhibit great enhancements in surface wettability and have a reduced recovery effect compared to the uncoated samples. The surface free energy and bonding adhesion are studied as well. The fucoidan-coated samples are found to have a larger adhesion strength than that of the EVOH samples (pristine and irradiated). Finally, surface morphology and roughness are traced by atomic force microscopy (AFM). The improvements in surface wettability and adhesion are attributed to the modified surface roughness and the increased surface polarity. To sum up, combining EB irradiation and fucoidan enhance the surface wettability of EVOH in a controlled way keeping the bulk properties unaffected.

Photo-triggered release from liposomes without membrane solubilization, based on binding to poly(vinyl alcohol) carrying a malachite green moiety.

Science.gov (United States)

Uda, Ryoko M; Kato, Yutaka; Takei, Michiko

2016-10-01

When working with liposomes analogous to cell membranes, it is important to develop substrates that can regulate interactions with the liposome surface in response to light. We achieved a photo-triggered release from liposomes by using a copolymer of poly(vinyl alcohol) carrying a malachite green moiety (PVAMG). Although PVAMG is a neutral polymer under dark conditions, it is photoionized upon exposure to UV light, resulting in the formation of a cationic site for binding to liposomes with a negatively charged surface. Under UV irradiation, PVAMG showed effective interaction with liposomes, releasing the encapsulated compound; however, this release was negligible under dark conditions. The poly(vinyl alcohol) moiety of PVAMG played an important role in the photo-triggered release. This release was caused by membrane destabilization without lipid solubilization. We also investigated different aspects of liposome/PVAMG interactions, including PVAMG-induced fusion between the liposomes and the change in the liposome morphologies. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis and characterization of CdxMn1-xS nanoparticles stabilized with poly(vinyl alcohol)

International Nuclear Information System (INIS)

Schatkoski, Vanessa M.; Mansur, Alexandra A.P.; Mansur, Herman S.; Gonzalez, Juan C.

2011-01-01

Colloidal luminescent semiconductor nanocrystals, also known as quantum dots, have attracted considerable attention due to their significant potential application. The doping of nanocrystalline semiconductors with divalent manganese ions results in new optical properties of these semimagnetic semiconductor quantum dots. In this work we report the synthesis and characterization Cd x Mn 1-x S nanoparticles using poly(vinyl alcohol) as stabilizing agent. Different fractions of Cd 2+ /Mn 2+ ions were investigated aiming the production of stable nanoparticles with different photoluminescence properties. (author)

Influence of vinyl chloride monomer and vinyl chloride monomer derivatives on hepatic DNA synthesis

International Nuclear Information System (INIS)

Brenner, E.A.

1982-01-01

Vinyl chloride monomer (VCM) is used extensively in the chemical industry, mainly in the production of polyvinyl chloride. It has recently been found to cause hepatic angiosarcoma. As VCM has also been shown to be mutagenic after metabolic activation the effect of VCM on DNA synthesis was investigated. [ 3 H]Thymidine incorporation into DNA was used to measure the rate of DNA synthesis in regenerating rat liver. A possible direct toxic effect of VCM or its metabolites on liver cell metabolism was examined by two unrelated techniques, viz. the measurement of adenine nucleotide concentrations in regenerating livers and the influence on transmembrane potentials in hepatocytes. The distribution of radioactivity in subcellular fractions following [ 14 C]VCM administration suggested microsomal conversion of VCM to an active form which was selectively retained in the nuclear fraction. Measurement of the activities of thymidine kinase and DNA polymerase in regenerating liver indicated that the induction of these enzymes which normally occurs after partial hepatectomy was not prevented by VCM treatment. Three techniques were used to test the hypothesis that the retardation in DNA synthesis was due to DNA damage: the prophage lambda induction test for DNA damage, autoradiographic detection of unscheduled thymidine incorporation into DNA, and detection of DNA strand breaks in alkaline sucrose gradients. All three provided evidence of DNA damage and led to the development of a novel technique to confirm these findings. This involved centrifugation in neutral sucrose gradients on intact double-stranded DNA contained in hepatocyte nucleoids and showed conclusively that VCM administration causes DNA strand breaks. Subsequent repair of DNA was also assessed by this technique. The site of the VCM/metabolite: DNA reaction was characterized by DNA thermal denaturation and renaturation studies

Properties of poly(vinyl alcohol)-borax gel doped with neodymium and praseodymium

International Nuclear Information System (INIS)

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

2014-01-01

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 Å and 15 Å, while small angle neutron scattering indicates that the rare-earth ions do not affect the nanoscale structures of the gels. Differential scanning calorimetry shows the glass transition temperature to increase with concentration of Pr in the gel. Excitation in the ultraviolet region leads to luminescent emission in the visible region. Simultaneous absorption in the visible region then leads to luminescent emission in the near infra-red region. The spectral qualities of the emission bands can be varied by choosing appropriate relative ratios of rare-earth species. (author)

Retardative chain transfer in free radical free-radical polymerisations of vinyl neo-decanoate in low molecular weight polyisoprene and toluene

NARCIS (Netherlands)

Monteiro, M.J.; Subramaniam, N.; Taylor, J.R.; Pham, B.T.T.; Tonge, M.P.; Gilbert, R.G.

2001-01-01

The kinetics of free-radical polymerisation of vinyl neo-decanoate (VneoD) and the molecular weight distributions (MWDs) of the polymers formed in the presence and absence of low molecular weight polyisoprene at 50°C under a variety of conditions were investigated. The bulk reaction was successfully

Temperature Dependent Electrical Transport in Al/Poly(4-vinyl phenol/p-GaAs Metal-Oxide-Semiconductor by Sol-Gel Spin Coating Method

Directory of Open Access Journals (Sweden)

Şadan Özden

2016-01-01

Full Text Available Deposition of poly(4-vinyl phenol insulator layer is carried out by applying the spin coating technique onto p-type GaAs substrate so as to create Al/poly(4-vinyl phenol/p-GaAs metal-oxide-semiconductor (MOS structure. Temperature was set to 80–320 K while the current-voltage (I-V characteristics of the structure were examined in the study. Ideality factor (n and barrier height (ϕb values found in the experiment ranged from 3.13 and 0.616 eV (320 K to 11.56 and 0.147 eV (80 K. Comparing the thermionic field emission theory and thermionic emission theory, the temperature dependent ideality factor behavior displayed that thermionic field emission theory is more valid than the latter. The calculated tunneling energy was 96 meV.

Process of irradiating an ethylene-vinyl acetate copolymer to produce low melt index copolymers, and products of said process

International Nuclear Information System (INIS)

Potts, J.E.

1976-01-01

Application of ionizing radiation in a dose between 0.5 and 1.5 megareps to copolymers of ethylene and vinyl acetate lowers the melt index and increases the toughness and flexibility of the copolymers without substantially decreasing solubility or thermoplasticity. The increased toughness and flexibility carries over into blends with wax or polyethylene. (author)

Predicting residential exposure to phthalate plasticizer emitted from vinyl flooring: a mechanistic analysis.

Science.gov (United States)

Xu, Ying; Hubal, Elaine A Cohen; Clausen, Per A; Little, John C

2009-04-01

A two-room model is developed to estimate the emission rate of di-2-ethylhexyl phthalate (DEHP) from vinyl flooring and the evolving gas-phase and adsorbed surface concentrations in a realistic indoor environment. Because the DEHP emission rate measured in a test chamber may be quite different from the emission rate from the same material in the indoor environment the model provides a convenient means to predict emissions and transport in a more realistic setting. Adsorption isotherms for phthalates and plasticizers on interior surfaces, such as carpet, wood, dust, and human skin, are derived from previous field and laboratory studies. Log-linear relationships between equilibrium parameters and chemical vapor pressure are obtained. The predicted indoor air DEHP concentration at steady state is 0.15 microg/m3. Room 1 reaches steady state within about one year, while the adjacent room reaches steady state about three months later. Ventilation rate has a strong influence on DEHP emission rate while total suspended particle concentration has a substantial impact on gas-phase concentration. Exposure to DEHP via inhalation, dermal absorption, and oral ingestion of dust is evaluated. The model clarifies the mechanisms that govern the release of DEHP from vinyl flooring and the subsequent interactions with interior surfaces, airborne particles, dust, and human skin. Although further model development, parameter identification, and model validation are needed, our preliminary model provides a mechanistic framework that elucidates exposure pathways for phthalate plasticizers, and can most likely be adapted to predict emissions and transport of other semivolatile organic compounds, such as brominated flame retardants and biocides, in a residential environment.

The effects of water absorption on an ester vinyl resin system

Directory of Open Access Journals (Sweden)

Ledjane Lima Sobrinho

2009-09-01

Full Text Available Derakene is a vinyl ester resin largely employed as matrix for polymeric based composite systems. In this work, the performance of such polymeric system was evaluated considering the effect of hygrothermal aging. The mechanical and thermal properties were examined for the processed material before and after ageing in water at 60 ºC for a maximum period of 64 days. Both analyses indicated the occurrence of post cure of the system after 16 days due to exposition at 60 ºC in water, which was also confirmed by analyses in samples with post cure treatment. Moreover, it was observed plasticizing of resin after 36 and 64 days of ageing. Micro structural and fracture surface analyses were carried out in order to characterize the samples. The appearance of surface voids was also observed.

Mechanical and dielectric properties of carbon nanotubes/poly (vinyl alcohol) nanocomposites

Science.gov (United States)

Amrin, Sayed; Deshpande, V. D.

2016-05-01

In this work, two series of nanocomposites of poly(vinyl alcohol) (PVA) incorporated with multiwalled carbon nanotubes (MWNT) and carboxyl functionalized multiwalled carbon nanotubes (MWNT-COOH) were fabricated using solution-cast method and their tensile and dielectric properties were studied. Tensile tests were carried out on composite films of MWNT/PVA and MWNT-COOH/PVA for different loading levels. Results show that overall mechanical properties of the MWNT-COOH/PVA composite was greatly improved as compared to the MWNT/PVA film. The dielectric properties of nanocomposites were investigated in a frequency range from 0.1Hz to 10MHz at room temperature respectively. Compared to MWNT/PVA composites, higher dielectric constant and ac conductivity was achieved in MWNT-COOH/PVA nanocomposite, which can be well explained by the interfacial polarization effect.

Formation of inorganic nanofibers by heat-treatment of poly(vinyl alcohol-zirconium compound hybrid nanofibers

Directory of Open Access Journals (Sweden)

Nakane K.

2013-01-01

Full Text Available Poly(vinyl alcohol-zirconium compound hybrid nanofibers (precursors were formed by electrospinning employing water as a solvent for the spinning solution. The precursors were converted into oxide (ZrO2, carbide (ZrC or nitride (ZrN nanofibers by heating them in air, Ar or N2 atmospheres. Monoclinic ZrO2 nanofibers with high-specific surface area were obtained by heat-treatment of the precursors in air. ZrC and ZrN nanofibers could be obtained below theoretical temperatures calculated from thermodynamics data.

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.

Preliminary studies on 1-vinyl-2-pyrrolidone grafting onto cellulose by pre-irradiation method

Energy Technology Data Exchange (ETDEWEB)

Severich, Patrick; Dutra, Rodrigo da Costa; Kodama, Yasko, E-mail: ykodama@ipen.br, E-mail: patrick.severich@ipen.br, E-mail: rodrigo.dutra@ipen.br [Instituto de Pesquisas Energética s e Nucleares (IPEN-CNEN/SP), São Paulo, SP (Brazil)

2017-07-01

Cellulose is considered a renewable biopolymer most abundant in nature. Better functional surfaces can be Obtained by modifying cellulose. On the other hand, poly vinyl pyrrolidone, PVP, is a synthetic nontoxic, water-soluble polymer frequently used in an extensive variety of applications including several pharmaceutical applications. Grafting 1-vinyl-2-pyrrolidone, NVP, onto polymeric cellulose can be obtained by ionizing radiation. Ionizing radiation grafting can be affected by several factors as environment, solvent, monomer concentration, temperature of graft reaction. Grafting by ionizing radiation can be performed by three methods, pre-irradiation, oxidation by peroxide and simultaneous irradiation. In this study, it was used pre-irradiation method of cellulose. Paper filter without ash, NVP without purification was used in this study. Paper samples were exposed to electron beam from Dynamitron Accelerator with radiation absorbed dose of 25 kGy. Influence of NVP concentration, temperature of reaction after irradiation on degree of grafting (DG) was studied. Also, cellulose radicals of grafted paper samples was studied by electron paramagnetic resonance using a Bruker X-band ESR at room temperature just after heating reaction. Small decrease of cellulose radicals was observed with increasing reaction temperature. It was observed DG small increase with increasing concentration of monomer in solution of water ethanol 50-50 v:v and rising temperature of reaction. Further tests using simultaneous method of grafting of NVP in cellulose paper, in water:ethanol 75:25 v:v solution, induced by gamma irradiation were performed. It was observed homopolymerization forming PVP with increasing monomer concentration. (author)

Preliminary studies on 1-vinyl-2-pyrrolidone grafting onto cellulose by pre-irradiation method

International Nuclear Information System (INIS)

Severich, Patrick; Dutra, Rodrigo da Costa; Kodama, Yasko

2017-01-01

Cellulose is considered a renewable biopolymer most abundant in nature. Better functional surfaces can be Obtained by modifying cellulose. On the other hand, poly vinyl pyrrolidone, PVP, is a synthetic nontoxic, water-soluble polymer frequently used in an extensive variety of applications including several pharmaceutical applications. Grafting 1-vinyl-2-pyrrolidone, NVP, onto polymeric cellulose can be obtained by ionizing radiation. Ionizing radiation grafting can be affected by several factors as environment, solvent, monomer concentration, temperature of graft reaction. Grafting by ionizing radiation can be performed by three methods, pre-irradiation, oxidation by peroxide and simultaneous irradiation. In this study, it was used pre-irradiation method of cellulose. Paper filter without ash, NVP without purification was used in this study. Paper samples were exposed to electron beam from Dynamitron Accelerator with radiation absorbed dose of 25 kGy. Influence of NVP concentration, temperature of reaction after irradiation on degree of grafting (DG) was studied. Also, cellulose radicals of grafted paper samples was studied by electron paramagnetic resonance using a Bruker X-band ESR at room temperature just after heating reaction. Small decrease of cellulose radicals was observed with increasing reaction temperature. It was observed DG small increase with increasing concentration of monomer in solution of water ethanol 50-50 v:v and rising temperature of reaction. Further tests using simultaneous method of grafting of NVP in cellulose paper, in water:ethanol 75:25 v:v solution, induced by gamma irradiation were performed. It was observed homopolymerization forming PVP with increasing monomer concentration. (author)

Measuring and predicting the emission rate of phthalate plasticizer from vinyl flooring in a specially-designed chamber.

Science.gov (United States)

Xu, Ying; Liu, Zhe; Park, Jinsoo; Clausen, Per A; Benning, Jennifer L; Little, John C

2012-11-20

The emission of di-2-ethylhexyl phthalate (DEHP) from vinyl flooring (VF) was measured in specially designed stainless steel chambers. In duplicate chamber studies, the gas-phase concentration in the chamber increased slowly and reached a steady state level of 0.8-0.9 μg/m(3) after about 20 days. By increasing the area of vinyl flooring and decreasing that of the stainless steel surface within the chamber, the time to reach steady state was significantly reduced, compared to a previous study (1 month versus 5 months). The adsorption isotherm of DEHP on the stainless steel chamber surfaces was explicitly measured using solvent extraction and thermal desorption. The strong partitioning of DEHP onto the stainless steel surface was found to follow a simple linear relationship. Thermal desorption resulted in higher recovery than solvent extraction. Investigation of sorption kinetics showed that it takes several weeks for the sorption of DEHP onto the stainless steel surface to reach equilibrium. The content of DEHP in VF was measured at about 15% (w/w) using pressurized liquid extraction. The independently measured or calculated parameters were used to validate an SVOC emission model, with excellent agreement between model prediction and the observed gas-phase DEHP chamber concentrations.

Surface chemistry of a pine-oil cleaner and other terpene mixtures with ozone on vinyl flooring tiles.

Science.gov (United States)

Ham, Jason E; Wells, J Raymond

2011-04-01

Indoor environments are dynamic reactors where consumer products (such as cleaning agents, deodorants, and air fresheners) emit volatile organic compounds (VOCs) that can subsequently interact with indoor oxidants such as ozone (O(3)), hydroxyl radicals, and nitrate radicals. Typically, consumer products consist of mixtures of VOCs and semi-VOCs which can react in the gas-phase or on surfaces with these oxidants to generate a variety of oxygenated products. In this study, the reaction of a pine-oil cleaner (POC) with O(3) (100ppb) on a urethane-coated vinyl flooring tile was investigated at 5% and 50% relative humidity. These results were compared to previous α-terpineol+O(3) reactions on glass and vinyl surfaces. Additionally, other terpene and terpene alcohol mixtures were formulated to understand the emission profiles as seen in the POC data. Results showed that the α-terpineol+O(3) reaction products were the prominent species that were also observed in the POC/O(3) surface experiments. Furthermore, α-terpineol+O(3) reactions generate the largest fraction of oxygenated products even in equal mixtures of other terpene alcohols. This finding suggests that the judicial choice of terpene alcohols for inclusion in product formulations may be useful in reducing oxidation product emissions. Published by Elsevier Ltd.

Synthesis and evaluation of water-soluble poly(vinyl alcohol)-paclitaxel conjugate as a macromolecular prodrug

International Nuclear Information System (INIS)

Kakinoki, Atsufumi; Kaneo, Yoshiharu; Tanaka, Tetsuro; Hosokawa, Yoshitsugu

2008-01-01

Paclitaxel (PTX) is an antitumor agent for the treatment of various human cancers. Cremophor EL and ethanol are used to formulate PTX in commercial injection solutions, because of its poor solubility in water. However, these agents cause severe allergic reaction upon intravenous administration. The aim of this study is to synthesize water-soluble macromolecular prodrugs of PTX for enhancing the therapeutic efficacy. Poly (vinyl alcohol) (PVA, 80 kDa), water-soluble synthetic polymer, was used as a drug carrier which is safe and stable in the body. The 2'-hydroxyl group of PTX was reacted with succinic anhydride and then carboxylic group of the succinyl spacer was coupled to PVA via ethylene diamine spacer, resulting the water-soluble prodrug of poly (vinyl alcohol)-paclitaxel conjugate (PVA-SPTX). The solubility of PTX was greatly enhanced by the conjugation to PVA. The release of PTX from the conjugate was accelerated at the neutral to basic conditions in in vitro release experiment. [ 125 I]-labeled PVA-SPTX was retained in the blood circulation for several days and was gradually distributed into the tumorous tissue after intravenous injection to the tumor-bearing mice. PVA-SPTX inhibited the growth of sarcoma 180 cells subcutaneously inoculated in mice. It was suggested that the water-solubility of PTX was markedly enhanced by the conjugation to PVA, and PVA-SPTX effectively delivered PTX to the tumorous tissue due to the enhanced permeability and retention (EPR) effect. (author)

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...... show that HTMA-PFP forms aggregates in water but becomes entangled by PVA (with a 1:1 molar ratio of HTMA-PFP to PVA) and eventually immersed in PVA clusters (with the ratio 1:4). This is attributed to the hydrophobic hydrophilic balance. Contrast variation data with regular and deuterated PVA support...

Preparation of Citric Acid Crosslinked Chitosan/Poly(Vinyl Alcohol Blend Membranes for Creatinine Transport

Directory of Open Access Journals (Sweden)

Retno Ariadi Lusiana

2016-08-01

Full Text Available Preparation of membrane using crosslinking reaction between chitosan and citric acid showed that functional group modification increased the number of active carrier groups which lead to better transport capacity of the membrane. In addition, the substitution of the carboxyl group increased creatinine permeation of chitosan membrane. The transport capacity of citric acid crosslinked chitosan membrane for creatinine was found to be 6.3 mg/L. The presence of cyanocobalamin slightly hindered the transport of creatinine although compounds did not able to pass through citric acid crosslinked chitosan/poly(vinyl alcohol blend membrane, as compounds no found in the acceptor phase.

A Tetrazine-Labile Vinyl Ether Benzyloxycarbonyl Protecting Group (VeZ): An Orthogonal Tool for Solid-Phase Peptide Chemistry.

Science.gov (United States)

Staderini, Matteo; Gambardella, Alessia; Lilienkampf, Annamaria; Bradley, Mark

2018-06-01

The vinyl ether benzyloxycarbonyl (VeZ) protecting group is selectively cleaved by treatment with tetrazines via an inverse electron-demand Diels-Alder reaction. This represents a new orthogonal protecting group for solid-phase peptide synthesis, with Fmoc-Lys(VeZ)-OH as a versatile alternative to Fmoc-Lys(Alloc)-OH and Fmoc-Lys(Dde)-OH, as demonstrated by the synthesis of two biologically relevant cyclic peptides.

Improving the Performances of Poly(vinylphosphonic acid) by Compositing or Copolymerization with Poly(4-(α-methyl)vinyl-1H-1,2,3-triazole)

International Nuclear Information System (INIS)

Han, Shuaiyuan; Yue, Baohua; Yan, Liuming

2014-01-01

Graphical abstract: - Highlights: • Poly(4-(α-methyl)vinyl-1H-1,2,3-triazole) is synthesized • PVPA/PMVTri polymeric composite proton conducting membranes are prepared • The proton conductivity of PVPA is improved by compositing with PMVTri • The water resistance of PVPA is improved by compositing with PMVTri • The oxidative stability is greatly improved - Abstract: The poly(vinylphosphonic acid) (PVPA), poly(4-(α-methyl)vinyl-1H-1,2,3-triazole) (PMVTri), and poly(VPA-co-MVTri) were synthesized, and proton exchange membranes were prepared based on the acid-base polymeric composite of PVPA and PMVTri, and acid-base amphoteric copolymer of poly(VPA-co-MVTri). The overall performances of PVPA, proton conductivity, thermal and oxidative stability, and water resistance, are greatly improved by compositing of PMVTri or copolymerization with 4-(α-methyl)vinyl-1H-1,2,3-triazole (MVTri). About four or eight folds improvement in maximum proton conductivity was observed in the polymeric composite of PVPA/PMVTri or acid-base amphoteric copolymer poly(VPA-co-MVTri) because of the redistribution of ions in the heterostructures of PVPA and PMVTri, respectively, compared with the pristine PVPA. At the same time, the oxidative stability and the water resistance of PVPA were also greatly improved attributing to the absent of α-H in the main chain of PMVTri and the acid-base interaction between the phosphonic acid groups and the triazolyl groups, respectively

Raman spectroscopy of poly (3-hydroxybutyrate) modified with poly (vinyl acetate) by radiation- induced copolymerization

International Nuclear Information System (INIS)

Gonzalez, Maykel; Galego Fernandez, Norma; Ortiz del Toro, Pedro; Rapado, Manuel; Paredes

2007-01-01

Poly (3-hydroxybutyrate) (PHB) is an important material used in the field of medicine. However in common conditions, PHB has some deficiencies. It is very brittle and slightly hydrophobic polymer. This somewhat limit its applications. Radiation chemistry can be used to improve its chemical properties. In the present study, the substrate, modified by radiation-induced graft copolymerization with vinyl acetate (VAc), was characterized using FTIR and Raman spectroscopy. FTIR spectroscopy did not reveal any significant bands but Raman spectroscopy revealed the formation of a new band that characterize the material

Thermodynamic and Kinetic Behavior of the Polystyrene/Poly(vinyl methyl ether) Blend as Studied by Excimer Fluorescence.

Science.gov (United States)

1986-01-02

AD-A±63 895 THERMODYNAMIC AND KINETIC BEHAVIOR OF THE / POLYSTYRENE/POLY(YINYL METHYL E..(U) STANFORD UNIY CALIFDEPT OF CHEMICAL ENGINEERING C N...Polystyrene/Poly(vinyl methyl ether) Blend 7. DEcFRMN 81 toOR 30USptE8 00~ as Studied by Excimer Fluorescence 6 EFRIGOG EOTNME *AUTHOR() a. CONTRACT OR GRANT...werea fondoare ihemoriisof * ~ Ex e sp fluodecositionsdu to deud Gen e and hoog Pinus Florsneis shownhase migrationprocSECURITY CLASIFICTIO OFd

Decreased material-activation of the complement system using low-energy plasma polymerized poly(vinyl pyrrolidone) coatings

DEFF Research Database (Denmark)

Andersen, T.E.; Kolmos, H.J.; Palarasah, Yaseelan

2011-01-01

In the current study we investigate the activation of blood complement on medical device silicone rubber and present a plasma polymerized vinyl pyrrolidone (ppVP) coating which strongly decreases surface-activation of the blood complement system. We show that uncoated silicone and polystyrene...... surface. The ppVP surface is furthermore characterized physically and chemically using scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR), which indicates preservation of chemical functionality by the applied plasma process. Overall, the pp...

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)

Polymerization of vinyl stearate multilayers by electron beam irradiation

International Nuclear Information System (INIS)

Nishii, Masanobu; Hatada, Motoyoshi

1975-01-01

Studies on the radiation-induced polymerization of vinyl stearate (VST) multilayers were carried out. The VST multilayers built-up on an aluminum plated glass plate by Langmuir-Blodgett technique were irradiated with electron beams from a Van de Graaff electron accelerator in nitrogen atmosphere. The structure of the multilayers and the effects of irradiation were investigated by X-ray diffractometry, contact angle measurement, multireflection infrared spectroscopy, and scanning electron microscopy. The VST multilayers became insoluble to methanol by the irradiation, and the multi-reflection infrared spectrum of the VST multilayers turned into that of poly (VST) with increasing dosage. The polymerization proceeded during the irradiation at the temperature range between -10 0 and 10 0 C, and the conversion attained to 90% within 2.5 minutes (total dose, 5.6 Mrads). The multilayers irradiated above 13 Mrads turned into the polymer film insoluble to benzene, indicating that the polymer chains were cross-linked by the irradiation. Stearic acid which was formed by the irradiation of VST at nitrogen-water interface as a hydrolysis product was not detected in this system. (auth.)

Polystyrene with pendant mixed functional ruthenium(II)-terpyridine complexes

NARCIS (Netherlands)

Heller, M.; Schubert, U.S.

2002-01-01

A vinyl substituted 2,2:6,2-terpyridine and a mixed, bifunctional ruthenium(II)-terpyridine complex bearing a vinyl and a hydroxymethyl group are utilized as comonomers for radical copolymerization with styrene. The resulting polymers are characterized by means of UV-vis spectroscopy and gel

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.

Dynamic mechanical properties of photopolymerizable poly(vinyl alcohol)-acrylate monomer blends

International Nuclear Information System (INIS)

Koshiba, M.; Yamaoka, T.; Tsunoda, T.

1983-01-01

Dynamic mechanical properties of photopolymerizable poly(vinyl alcohol) (PVA)-monoacrylate blends were investigated by measuring dynamic shear modulus G' and loss tangent, tan delta. The dynamic mechanical properties of the blends before being exposed to UV irradiation were governed by the weight percent of the monomers which act as plasticizers. On the other hand, the UV-irradiated blends seemed to be typical two-phase materials since they revealed two tan delta maxima whose positions were independent of the monomer content. Those two maxima were assigned to PVA and photopolymerized acrylates with reference to the dynamic mechanical data of PVA and a PVA-polyacrylamide polyblend. Those dynamic mechanical data suggested that insolubilization of the blend type photopolymers should be caused by a decrease in solubility due to graft polymerization of acrylate monomers onto PVA. 9 figures, 3 tables

Poly(vinyl pyrrolidone)-Chitosan implant for endoscopic treatment of vesicoureteral reflux

International Nuclear Information System (INIS)

Relleve, Lorna S.; Abad, Lucille V.; Aranilla, Charito T.; Dela Rosa, A.M.; Bolong, David T.; Bisnar, Carlo C.

2008-01-01

Radiation-crosslinked poly(vinyl pyrrolidone) (PVP)-Chitosan was prepared as a potential injectable implant for endoscopic treatment of vesicoureteral reflux (VUR). The physical and histological properties of PVP-Chitosan implant in comparison with the commercial dextranomer/hyaluronic acid copolymer (Deflux) have been evaluated in vivo by subcutaneous and abdominal injection in rats over a period of 6 months. The PVP-Chitosan implant was easily injected through 26-gauge needle. Monthly gross examination of the implanted sites showed no significant decrease in volume of implant and no local inflammatory reaction. Histological findings indicated no evidence of migration to the distant organs after 6 months of implantation. Results of this study indicated that PVP-Chitosan implant has properties of a good tissue augmenting substance such as stability, biocompatibility and non-migration but long-term studies are needed to evaluate its therapeutic efficiency. (author)

Reinforcement of poly (vinyl alcohol films with alpha-chitin nanowhiskers

Directory of Open Access Journals (Sweden)

Hugo Lisboa

2018-03-01

Full Text Available Abstract Composites Films were produced using Poly (Vinyl Alcohol as the soft material and reinforced with Chitin Nanowhiskers(NWCH as the rigid material. The present work studies the reinforcing mechanisms of NWCH in PVA films, made through a solvent casting technique and characterized for their calorimetric, swelling and mechanical properties. DSC tests revealed a sharp increase of 45 °C in glass transition temperatures with only 1.5% NWCH, while melting temperature had a small increases suggesting an anti-plasticizing effect. Swelling tests revealed decreasing hygoscopy when NWCH volume fraction increases. Estimates for elastic tensile modulus using a model that predicts the formation of a percolating network were not consistent with the experimental data of tensile tests suggesting that contrary to the reinforcement with cellulose nanowhiskers the percolating network is not primarily responsible for the reinforcement of the films. By adjusting the Halpin-Tsai equations, modified by Nielsen it was found that the mechanical properties were mainly influenced by the packing of the NWCH.

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)

Copolymerization parameters of N-Methacryloyloxy tetrabromophthalimide with different vinyl monomers

International Nuclear Information System (INIS)

Mahmoud, A.A.

2005-01-01

N-Methacryloyloxytetrabromophthalimide (NMTP) was synthesized by the reaction of N-hydroxytetrabromophthalimide with either methacryloyl chloride or methacrylic acid in the presence of triethylamine or N, Ndicyclohexylcarbodiimide respectively. Binary copolymerization reactions of the prepared monomer with ethyl acrylate (EA), n-butyl methacrylate (n.BMA), tertiary butylacrylate (t.BA) and vinyl acetate (VA) were performed in methylene chloride at 65 degree C using 1 mol % azobisisobutylronitrile (AIBN) as initiator. The structure of the prepared monomer was investigated by IR and 1H NMR spectroscopy. The copolymer compositions were determined from bromine analysis. Copolymerization parameters for each system were calculated by the Fineman-Ross and Kelen-Tudos methods. The monomer reactivity ratios for the systems NMTP-EA, NMTP-n.BMA, NMTP-t.BA and NMTP-VA were found to be r1 0.180, r2 = 0.893, r1 = 0.025, r2 = 0.680, r1 0.014, r2 0.956 and r1 1.002, r2 1.004 respectively

The influence of surface oxygen and hydroxyl groups on the dehydrogenation of ethylene, acetic acid and hydrogenated vinyl acetate on pure Pd(1 0 0): A DFT study

Energy Technology Data Exchange (ETDEWEB)

Huang, Yanping [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin (China); Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072 (China); Dong, Xiuqin [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin (China); Yu, Yingzhe, E-mail: yzhyu@tju.edu.cn [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin (China); Zhang, Minhua, E-mail: mhzhangtj@163.com [Key Laboratory for Green Chemical Technology of Ministry of Education, R& D Center for Petrochemical Technology, Tianjin University, Tianjin (China)

2016-12-01

Highlights: • All dehydrogenation reactions in vinyl acetate synthesis on Pd(1 0 0) were studied. • The energy barriers of the transition state of the three reactions were calculated. • The influence of surface Os and OHs on all dehydrogenation actions was discussed. - Abstract: On the basis of a Langmuir–Hinshelwood-type mechanism, the dehydrogenation of ethylene, acetic acid and hydrogenated vinyl acetate (VAH) on pure Pd(1 0 0) with surface oxygen atoms (Os) and hydroxyl groups (OHs) was studied with density functional theory (DFT) method. Our calculation results show that both Os and OHs can consistently reduce the activation energies of dehydrogenation of ethylene, acetic acid and VAH to some degree with only one exception that OHs somehow increase the activation energy of VAH. Based on Langmuir–Hinshelwood mechanism, the three dehydrogenation reactions in presence of surface Os and OHs are almost consistently favored, compared with the corresponding processes on clean Pd(1 0 0) surfaces, and thus a Langmuir–Hinshelwood-type mechanism may not be excluded beforehand when investigating the microscopic performance of the oxygen-assisted vinyl acetate synthesis on Pd(1 0 0) catalysts.

Gamma irradiation Effect on the Non-Crosslinked and Crosslinked Poly(vinyl alcohol) Films

International Nuclear Information System (INIS)

El-Sawy, N.M.; El-Arnaouty, M.B.; Abdel Ghaffar, A.M.

2008-01-01

The non-crosslinked and crosslinked poly(vinyl alcohol) (PVA) films were prepared by the cast method then irradiated with gamma rays for various doses up to 300 kGy. The structure and characterization of PVA were determined by using Infrared spectroscopy (FTIR), ultraviolet spectroscopy (UV). Swelling behaviour was also investigated. Mechanical properties have been examined with respect to the absorbed dose. The color of the films changed to yellowish-white after irradiation. Additional changes were observed using FTIR analysis on the degradation products demonstrated that the radiolysis of PVA was initiated by liberation of H and OH groups leading to scission of the main chains and formation of carbonyl and double bond groups. Thermogravimetric analysis (TGA) was performed

Accumulation of long-chain bases in yeast promotes their conversion to a long-chain base vinyl ether

OpenAIRE

Martínez-Montañés, Fernando; Lone, Museer A.; Hsu, Fong-Fu; Schneiter3, Roger

2017-01-01

Long-chain bases (LCBs) are the precursors to ceramide and sphingolipids in eukaryotic cells. They are formed by the action of serine palmitoyl-CoA transferase (SPT), a complex of integral membrane proteins located in the endoplasmic reticulum. SPT activity is negatively regulated by Orm proteins to prevent the toxic overaccumulation of LCBs. Here we show that overaccumulation of LCBs in yeast results in their conversion to a hitherto undescribed LCB derivative, an LCB vinyl ether. The ...

Nanofibre Electrospinning Poly(vinyl alcohol and Cellulose Composite Mats Obtained by Use of a Cylindrical Electrode

Directory of Open Access Journals (Sweden)

Anna Sutka

2013-01-01

Full Text Available A study of nanofibre composites obtained by electrospinning from poly(vinyl alcohol (PVA solutions of steam exploded hemp fibres and shives is reported. A combined treatment of steam explosion (SE, ball milling, and high-intensity ultrasound (HIUS is applied to prepare cellulose nanofibres (CNF from hemp fibres (CNF-F and shives (CNF-S. The reflectance Fourier transform infrared (FTIR ATR spectroscopy is used to analyze the obtained PVA/CNF composite mats. Morphology of the PVA/CNF composites was studied by scanning electron microscopy (SEM.

Predictive values of some atherogenic risk factors in young workers occupationally exposed to vinyl chloride and heavy metals

Directory of Open Access Journals (Sweden)

Aziza Abdel Azim Saad

2017-01-01

Full Text Available Traditional risk factors do not explain all of the risk for incident coronary heart disease (CHD events. Human susceptibility to atherosclerosis and consequently coronary heart disease is maximally exhibited when the environment is unfavorable, especially in workplace. Thus, the present work was undertaken to study the relation of lipoprotein (a to the other atherogenic risk factors in young workers occupationally exposed to vinyl chloride or some heavy metals by studying the effect of exposure to these agents on the lipid profiles, immunological parameters and the antioxidant defense enzyme system. The results of this study revealed that, in metalists, the cluster features of dyslipidemia, impairment in antioxidant defense mechanism and high levels of Lp (a, CICs, C3 and C4 represent unfortunate events on their cardiovascular system. In VCW, vinyl chloride metabolites caused severe oxidative stress reflected by impairment in the antioxidant defense accompanied by propagation of lipid peroxidation. Additionally, the elevated levels of Lp (a, CICs, C3 and C4 may point out to their role as atherogenic risk factors in those workers. In conclusion, young workers occupationally exposed to VC may be at high risk of developing cardiovascular disease in spite of having normolipidemia.

Assessment of ethylene vinyl-acetate copolymer samples exposed to γ-rays via linearity analyses

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Lucas N. de; Nascimento, Eriberto O. do; Schimidt, Fernando [Instituto Federal de Educação, Ciência e Tecnologia de Goiás (IFG), Goiânia, GO (Brazil); Antonio, Patrícia L.; Caldas, Linda V.E., E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

2017-07-01

Materials with the potential to become dosimeters are of interest in radiation physics. In this research, the materials were analyzed and compared in relation to their linearity ranges. Samples of ethylene vinyl-acetate copolymer (EVA) were irradiated with doses from 10 Gy to 10 kGy using a {sup 60}Co Gamma-Cell system 220 and evaluated with the FTIR technique. The linearity analyses were applied through two methodologies, searching for linear regions in their response. The results show that both applied analyses indicate linear regions in defined dose interval. The radiation detectors EVA can be useful for radiation dosimetry in intermediate and high doses. (author)

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.

Preparation, Characterization and Permeation Behavior of Poly(methyl acrylate-Poly(dimethyl siloxane-Poly(methyl acrylate Block Copolymer/Poly(vinyl acetate Blend Membranes

Directory of Open Access Journals (Sweden)

Mohammad Ali Semsarzadeh

2015-03-01

Full Text Available Structure of polymeric materials is of the most important factors in determination of the characteristics and properties of the membranes. Various research and developments on polymeric membranes confirm the direct correlation between structure-properties of polymeric membranes. In this research, the structural outcome of poly(methyl acrylate-poly(dimethyl siloxane-poly(methyl acrylate/poly(vinyl acetate blend membranes and its relationship with gas permeation behavior of the blends were investigated. The flexible block copolymer of poly(methyl acrylate-poly(dimethyl siloxane-poly(methyl acrylate (PMA-PDMS-PMA was synthesized via atom transfer radical polymerization. Morphology and chemical structure of the synthesized block copolymer was investigated by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, gel permeation chromatography, X-ray diffraction analysis, differential scanning calorimetry and scanning electron microscopy. Blend membranes of PMA-PDMS-PMA and poly(vinyl acetate (PVAc were prepared by solution casting method in different compositions. By adding poly(vinyl acetate to PMA-PDMS-PMA block copolymer, the selectivity of the membranes for carbon dioxide/methane pair gases were increased by 55%. Fractional free volume (an indication of chain packing efficiency in blend membranes and dielectric constant (an indication of the molar volume and molar polarization of the blend membranes were obtained as the factors reflected the microstructural effect of PMA-PDMS-PMA and PVAc blend membranes. The efforts were directed toward expressing more precise structure-properties relationship of PMA-PDMS-PMA/PVAc blend membranes. The experimental permeability values of the blend membranes reported in this research were compared with the modified logarithmic model. The modified logarithmic model was evaluated for other blend membranes.

Synthesis of (1R,2S)-1-amino-2-vinylcyclopropanecarboxylic acid vinyl-ACCA) derivatives: key intermediates for the preparation of inhibitors of the hepatitis C virus NS3 protease.

Science.gov (United States)

Beaulieu, Pierre L; Gillard, James; Bailey, Murray D; Boucher, Colette; Duceppe, Jean-Simon; Simoneau, Bruno; Wang, Xiao-Jun; Zhang, Li; Grozinger, Karl; Houpis, Ioannis; Farina, Vittorio; Heimroth, Heidi; Krueger, Thomas; Schnaubelt, Jürgen

2005-07-22

(1R,2S)-1-Amino-2-vinylcyclopropanecarboxylic acid (vinyl-ACCA) is a key building block in the synthesis of potent inhibitors of the hepatitis C virus NS3 protease such as BILN 2061, which was recently shown to dramatically reduce viral load after administration to patients infected with HCV genotype 1. We have developed a scalable process that delivers derivatives of this unusual amino acid in >99% ee. The strategy was based on the dialkylation of a glycine Schiff base using trans-1,4-dibromo-2-butene as an electrophile to produce racemic vinyl-ACCA, which was subsequently resolved using a readily available, inexpensive esterase enzyme (Alcalase 2.4L). Factors that affect diastereoselection in the initial dialkylation steps were examined and the conditions optimized to deliver the desired diastereomer selectively. Product inhibition, which was encountered during the enzymatic resolution step, initially resulted in prolonged cycle times. Enrichment of racemic vinyl-ACCA through a chemical resolution via diastereomeric salt formation or the use of forcing conditions in the enzymatic reaction both led to improvements in throughput and the development of a viable process. The chemistry described herein was scaled up to produce multikilogram quantities of this building block.

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.

Synthesis and thermal characterization of CdS nano crystals in previously formed template of maleic anhydride-octene 1-vinyl butyl terpolymer

International Nuclear Information System (INIS)

Akbarov, O.H; Mammadova, R.E; Malikov, E.Y.

2008-01-01

Full text: Nano crystals have dimensions in the range 10100 nm. Crystals in this size range possess unique properties, which enable scientists to manufacture materials and devices capable of performing unimaginable tasks. For that reason synthesis of this semiconductor nano crystals is expedient. Many useful methods have been used for preparing sulphide semiconductor nano crystals, such as colloidal chemistry method, sol-gel method, inverse micelle method, in situ synthesis and assemble on polymer template. The most significant method is in situ synthesis and assemble of sulphide semiconductor nano crystals on polymer. Compared with other methods, the stability of nanoparticles is improved by the protection and confinement of the copolymer. Because of confinement and protection effects of template environmental risk is prevented in this method. On the base of this principles in situ synthesis of CdS nano crystals in maleic anhydride-octene 1-vinyl butyl terpolymer was realized in this scientific work. First of all in specific condition maleic anhydride, octene 1, and vinyl butyl ether were polymerized to form a terpolymer as the result of radical ter polymerization. In second step CdS nano crystals were synthesized in N,N-dimethylformamide solution of maleic anhydride-octene 1-vinyl butyl terpolymer through the reaction of thiourea with cadmium chloride. In this process CdCI 2 x 2.5H 2 O was dissolved in N,N-dimethylformamide solution of previously formed terpolymer and was heated in 90 0 C temperature for 4 hours with vigorous stirring. Then desired amount of thiourea in N,N-dimethylformamide was quickly injected into the reaction flask using a syringe. The reaction continued for another 1 hour, and a yellow clear solution was obtained, which indicated the formation of CdS nano crystals

Chemically imaging the effects of the addition of nanofibrillated cellulose on the distribution of poly(acrylic acid) in poly(vinyl alcohol)

Science.gov (United States)

Craig Clemons; Julia Sedlmair; Barbara Illman; Rebecca Ibach; Carol Hirschmugl

2013-01-01

The distribution of poly(acrylic acid) (PAA) in model laminates of nanocellulose and poly(vinyl alcohol) (PVOH) was investigated by FTIR chemical imaging. The method was effective in spatially discerning the three components of the composite. PAA can potentially improve the performance of nanocellulose reinforced PVOH by not only crosslinking the PVOH matrix but also...

Dynamics in poly vinyl alcohol (PVA) based hydrogel: Neutron scattering study

Energy Technology Data Exchange (ETDEWEB)

Prabhudesai, S. A., E-mail: swapnil@barc.gov.in; Mitra, S.; Mukhopadhyay, R. [Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 40085 (India); Lawrence, Mathias B. [Department of Physics, St. Xavier’s College, Mapusa, Goa 403507 (India); Desa, J. A. E. [Department of Physics, Goa University, Taleigao Plateau, Goa 403206 (India)

2015-06-24

Results of quasielastic neutron scattering measurements carried out on Poly Vinyl Alcohol (PVA) based hydrogels are reported here. PVA hydrogels are formed using Borax as a cross-linking agent in D{sub 2}O solvent. This synthetic polymer can be used for obtaining the hydrogels with potential use in the field of biomaterials. The aim of this paper is to study the dynamics of polymer chain in the hydrogel since it is known that polymer mobility influences the kinetics of loading and release of drugs. It is found that the dynamics of hydrogen atoms in the polymer chain could be described by a model where the diffusion of hydrogen atoms is limited within a spherical volume of radius 3.3 Å. Average diffusivity estimated from the behavior of quasielastic width is found to be 1.2 × 10{sup −5} cm{sup 2}/sec.

Investigation of morphology and bioactive properties of composite coating of HA/vinyl acetate on pure titanium

International Nuclear Information System (INIS)

Afshar, Abdollahe; Yousefpour, Mardali; Xiudong, Yang; Li Xudong; Yang Bangcheng; Wu Yao; Chen Jiyong; Zhang Xingdong

2006-01-01

Electrochemical co-deposition approach was expanded to prepare composite bio-ceramic coating of hydroxyapatite (HA)/polyvinyl acetate on the surface of titanium. The role is to improve the bioactive and crystallization properties. The results of XRD, XPS, SEM and TEM characterization showed that by increasing amount of vinyl acetate in the composite bio-ceramic coating before and after immersing in the simulated body fluid (SBF), an oriented growth of HA planes on the (0 0 2) direction had been observed on titanium substrate. Also significant surface morphology changes were obtained

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.

Thermotolerant cyclamen with reduced acrolein and methyl vinyl ketone.

Science.gov (United States)

Kai, Hiroomi; Hirashima, Keita; Matsuda, Osamu; Ikegami, Hidetoshi; Winkelmann, Traud; Nakahara, Takao; Iba, Koh

2012-06-01

Reduced levels of trienoic fatty acids (TAs) in chloroplast membranes induce thermotolerance in several plant species, but the underlying mechanisms remain unclear. TA peroxidation in plant cell membranes generates cytotoxic, TA-derived compounds containing α,β-unsaturated carbonyl groups. The relationship between low TA levels and the amounts of cytotoxic TA-derived compounds was examined using thermotolerant transgenic cyclamen (Cyclamen persicum Mill.) with low TA contents. Changes in the levels of the cytotoxic TA-derived acrolein (ACR), methyl vinyl ketone (MVK), (E)-2-hexenal, 4-hydroxy-2-nonenal, and malondialdehyde were analysed in the leaf tissues of wild-type (WT) and thermotolerant transgenic cyclamen under heat stress. Levels of ACR and MVK in the WT increased in parallel with the occurrence of heat-induced tissue damage, whereas no such changes were observed in the thermotolerant transgenic lines. Furthermore, exogenous ACR and MVK infiltrated into leaves to concentrations similar to those observed in heat-stressed WT leaves caused similar disease symptoms. These results suggest that thermotolerance in transgenic cyclamen depends on reduced production rates of ACR and MVK under heat stress, due to the low level of TAs in these plants.

Synthesis of 2-azaspiro[4.4]nonan-1-ones via phosphine-catalysed [3+2]-cycloadditions

Energy Technology Data Exchange (ETDEWEB)

Yong, Sarah R.; Williams, Morwenna C.; Pyne, Stephen G.; Ung, Alison T.; Skelton, Brian W.; White, Allan H.; Turner, Peter (UWA); (Wollongong); (Sydney)

2008-10-03

The phosphine-catalyzed [3+2]-cycloaddition of the 2-methylene {gamma}-lactams 4 and 5 and the acrylate 6 with the ylides derived from the ethyl ester, the amide or the chiral camphor sultam derivative of 2-butynoic acid (7a-c) give directly, or indirectly after reductive cyclization, spiro-heterocyclic products. The acid 32 underwent Curtius rearrangement and then acid hydrolysis to give two novel spiro-cyclic ketones, 41 and 42.

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.

Fabrication and Characterization of Electrospun Wool Keratin/Poly(vinyl alcohol Blend Nanofibers

Directory of Open Access Journals (Sweden)

Shuai Li

2014-01-01

Full Text Available Wool keratin/poly(vinyl alcohol (PVA blend nanofibers were fabricated using the electrospinning method in formic acid solutions with different weight ratios of keratin to PVA. The resultant blend nanofibers were characterized by scanning electron microscopy (SEM, Fourier transform infrared (FTIR, X-ray diffraction (XRD, thermal gravimetric analysis (TGA, and tensile test. SEM images showed that the diameter of the blend nanofibers was affected by the content of keratin in blend solution. FTIR and XRD analyses data demonstrated that there were good interactions between keratin and PVA in the blended nanofibers caused by possibly hydrogen bonds. The TGA study revealed that the thermal stability of the blend nanofibers was between those of keratin and PVA. Tensile test indicated that the addition of PVA was able to improve the mechanical properties of the electrospun nanofibers.

Comparison of the solar collection efficiencies of various vinyl house

Energy Technology Data Exchange (ETDEWEB)

Park, K H; Shin, H N; Lee, D S; Shin, D H; Suh, K B

1982-01-01

Three plastic film solar dryers covered with different film layers were constructed by modifying a farm vinyl house and studying their performance. The collection efficiency and temperature raising of type C which was covered with double layers of transparent PE and black PVC film was most efficient, followed by B (which was covered with a double layer of transparent PE film) and type A (which was covered with single layer transparent PE film). The inside temperature of type C averaged 18/sup 0/C higher than ambient temperature and its collection efficiency was 31.5% with air flow rate of 3.8 m/sup 3//min. The solar energy collection efficiency of type C was increased in proportion to air flow rate up to 60.2% at 11.3 m/sup 3//min. In a demonstration drying test of red pepper in type C, drying capacity per unit area was 2.5 times higher than that of conventional solar drying on straw mat and drying time shortened to about half.

Degradation of poly(vinyl chloride) films by X-rays radiation

International Nuclear Information System (INIS)

Sbampato, M.E.; Kawano, Y.

1984-01-01

The degradation of pure poly(vinyl chloride) (PVC) films has been studied by X-rays radiation in vacuum. The films are transparent and become yellow with the exposure of radiation and this colour is enhanced with the time of irradiation. The infrared, ultraviolet and visible spectra changed in the irradiated material. The IR spectra show changes in itensities and band shifting, particularly in the region of C-Cl stretching vibrations indicating the occurrence of dehydrochlorination and a change in the conformation of the degraded PVC. The ultraviolet and visible spectra of irradiated films show a strong absorption band at 240 nm and many shoulders which are associated to dyenes, carbonyl and polyenes with few double bonds formed. The shoulder numbers increase in the spectra of samples kept for three months. This effect indicates that with irradiation, HCl is evolved resulting in the formation of polyenyl radicals, which propagate after irradiation. At the same time, should occur the reaction of these radicals with the atmospheric oxygen with formation of C=0 bonds. (Author) [pt

Characterization of Functionalized Acrylic acid /4- Vinyl Pyridine Graft Copolymers

International Nuclear Information System (INIS)

Kamal, H.; Mahmoud, Gh.A.; Hegazy, D.E.

2009-01-01

Properties and characterization of the membranes prepared by radiation grafting of acrylic acid (AAc) or/ and 4-vinyl pyridine (4VP) onto low density polyethylene (LDPE) and polypropylene (PP) films were carried out. The FTIR spectra for the grafted membranes were studied to evaluate the structure change as a result of grafting. The swelling behaviour of the graft copolymer in methanol was studied. It was found that the grafting of AAc and/ or 4- VP onto LDPE and PP resulted in introducing good hydrophilic properties to such polymer substrates. The hydrophilic properties were directly proportional to the amount of functional groups. The mechanical properties (Young's modulus, elongation percent and tensile strength) of the grafted membranes also, have been investigated. As the grafting degree increases, the modulus also increases. Increasing the hydrophilicity of the membranes by chemical treatment enhances its mechanical properties. The thermal parameters of the grafted membranes such as δH m1 . δH m2 , and T rc have been also studied by using DSC

Fabrication and EMI shielding effectiveness of Ag-decorated highly porous poly(vinyl alcohol)/Fe2O3 nanofibrous composites

International Nuclear Information System (INIS)

Kim, Hae-Rim; Kim, Byoung-Suhk; Kim, Ick-Soo

2012-01-01

The Ag-decorated poly(vinyl alcohol) (PVA) composite nanofibrous webs incorporating Fe 2 O 3 nanoparticles were fabricated by electrospinning and metal-deposition methods for electromagnetic interference (EMI) shielding applications. The Ag-decorated PVA/Fe 2 O 3 composite nanofiber webs with various Ag thicknesses and different amounts of Fe 2 O 3 nanoparticles were prepared and used for EMI shielding measurement. For the EMI SE measurement, a near-field antenna measurement system was used. The measurement of EMI SE was carried out at the frequency range from 0.5 to 18 GHz, and the electromagnetic parameters were measured. The morphologies and microstructures of the resultant PVA/Fe 2 O 3 composite nanofiber webs were characterized using field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM), respectively. The effects of surface morphologies and Fe 2 O 3 nanoparticles on the EMI shielding effectiveness of Ag-decorated PVA/Fe 2 O 3 composite nanofiber webs were investigated. -- Highlights: ► We prepare Ag-decorated poly(vinyl alcohol) nanowebs incorporating Fe 2 O 3 nanoparticles. ► Solvents will affect the fiber morphologies and Fe 2 O 3 nanoparticles dispersion. ► EMI shielding effectiveness depends on the metal thickness and Fe 2 O 3 nanoparticles dispersion.

Radiation curing of mixture of diallylphthalate prepolymer and vinyl monomer, 11

International Nuclear Information System (INIS)

Gotoda, Masao; Yagi, Toshiaki; Yoshizawa, Iwao; Okugawa, Hideo.

1975-01-01

Preparation of Wood-Polymer Composite (WPC) piled plywood for flooring, was attempted by electron beam irradiation of American Hemlock veneer, impregnated with low molecular weight diallylphthalate prepolymer (DAPsub(p).L)/vinyl monomer mixtures, in comparison with that by thermal curing reported previously. For the improvement of the mechanical properties of WPC piled plywood, 5-15 parts of low molecular weight polyvinylacetate (PVAc) was added to DAPsub(p).L/methyl acrylate/hydroxyethyl acrylate/benzoyl peroxide (50/40/10/2) mixture. The addition of PVAc did not give much influence to the degree of impregnation in the veneer and to the curability by electron beam irradiation. As to the resistance to hot and cold cycle test, WPC piled plywood, prepared by the resin containing 5 parts of PVAc gave the best results. As a general conclusion, due to the superior mechanical properties, the WPC piled plywood processed by electron beam irradiation is suitable for flooring use. (author)

Metal-Mediated Halogen Exchange in Aryl and Vinyl Halides: a Review

Science.gov (United States)

Evano, Gwilherm; Nitelet, Antoine; Thilmany, Pierre; Dewez, Damien F.

2018-04-01

Halogenated arenes and alkenes are of prime importance in many areas of science, especially in the pharmaceutical, agrochemical and chemical industries. While the simplest ones are commercially available, some of them are still hardly accessible depending on their substitution patterns and the nature of the halogen atom. Reactions enabling the selective and efficient replacement of the halogen atom of an aryl or alkenyl halide by another one, lighter or heavier, are therefore of major importance since they can be used for example to turn a less reactive aryl/alkenyl chloride into the more reactive iodinated derivatives or, in a reversed sense, to block an undesired reactivity, for late-stage modifications or for the introduction of a radionuclide. If some halogen exchange reactions are possible with activated substrates, they usually require catalysis with metal complexes. Remarkably efficient processes have been developed for metal-mediated halogen exchange in aryl and vinyl halides: they are overviewed, in a comprehensive manner, in this review article.

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.

Domino Aza-Michael-ih-Diels-Alder Reaction to Various 3-Vinyl-1,2,4-triazines: Access to Polysubstituted Tetrahydro-1,6-naphthyridines.

Science.gov (United States)

Jouha, Jabrane; Buttard, Floris; Lorion, Magali; Berthonneau, Clément; Khouili, Mostafa; Hiebel, Marie-Aude; Guillaumet, Gérald; Brière, Jean-François; Suzenet, Franck

2017-09-15

A straightforward domino aza-Michael-inverse-electron-demand-hetero-Diels-Alder/retro-Diels-Alder reaction between primary and secondary propargylamine derivatives and 3-vinyl-1,2,4-triazines is developed highlighting not only the uniqueness of this dual-heterocyclic platform but also a novel and unprecedented path to polysubstituted tetrahydro-1,6-naphthyridine scaffolds.

Thermodynamic and kinetic analysis of phase separation of temperature-sensitive poly(vinyl methyl ether) in the presence of hydrophobic tert-butyl alcohol

Czech Academy of Sciences Publication Activity Database

Velychkivska, Nadiia; Bogomolova, Anna; Filippov, Sergey K.; Starovoytova, Larisa; Labuta, J.

2017-01-01

Roč. 295, č. 8 (2017), s. 1419-1428 ISSN 0303-402X R&D Projects: GA ČR(CZ) GC15-10527J Institutional support: RVO:61389013 Keywords : phase separation * coil-globule transition * poly(vinyl methyl ether) Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.723, year: 2016

Surface grafting of poly(ethylene glycol) onto poly(acrylamide-co-vinyl amine) cross-linked films under mild conditions.

Science.gov (United States)

Yamamoto, Y; Sefton, M V

1998-01-01

Poly(ethylene glycol) (PEG) was grafted onto poly(acrylamide-co-vinyl amine) (poly(AM-co-VA)) film using tresylated PEG (TPEG) at 37 degrees C in aqueous buffers (pH 7.4) with a view to surface-modifying microencapsulated mammalian cells. Poly(AM-co-VA) film was synthesized by Hofmann degradation of a cross-linked poly(acrylamide) film. Conversion to vinyl amine on the surface of the film was approximately 50%, but bulk conversion was not observed; surface specificity was thought to be the result of cleavage of aminated polymer chains at the surface due to chain scission. Reaction between primary amine and TPEG gave a graft yield of 2 mol% (based on XPS) with respect to available surface amine groups, equivalent to 54 mol% ethylene oxide based on monomer units. Physical adsorption of non-activated polymer was done under identical conditions as a control and the difference in oxygen content was significant compared to TPEG. The type of buffer agent and buffer concentration did not influence graft yields. This graft reaction, which was completed in as little as 2 h was considered to be mild enough to be used for a surface modification of microcapsules containing cells without affecting their viability. Such a surface modification technique may prove to be a useful means of enhancing the biocompatibility of microcapsules (or any tissue engineering construct) even after cell encapsulation or seeding.

Potentiometric titration of polyhexamethylene biguanide hydrochloride with potassium poly(vinyl sulfate) solution using a cationic surfactant-selective electrode.

Science.gov (United States)

Masadome, Takashi; Yamagishi, Yuichi; Takano, Masaki; Hattori, Toshiaki

2008-03-01

A potentiometric titration method using a cationic surfactant as an indicator cation and a plasticized poly(vinyl chloride) membrane electrode sensitive to the cationic surfactant is proposed for the determination of polyhexamethylene biguanide hydrochloride (PHMB-HCl), which is a cationic polyelectrolyte. A sample solution of PHMB-HCl containing an indicator cation (hexadecyltrimethylammonium ion, HTA) was titrated with a standard solution of an anionic polyelectrolyte, potassium poly(vinyl sulfate) (PVSK). The end-point was detected as a sharp potential change due to an abrupt decrease in the concentration of the indicator cation, HTA, which is caused by its association with PVSK. The effects of the concentrations of HTA ion and coexisting electrolytes in the sample solution on the degree of the potential change at the end-point were examined. A linear relationship between the concentration of PHMB-HCl and the end-point volume of the titrant exists in the concentration range from 2.0 x 10(-5) to 4.0 x 10(-4) M in the case that the concentration of HTA is 1.0 x 10(-5) M, and that from 1.0 x 10(-6) to 1.2 x 10(-5) M in the case that the concentration of HTA is 5.0 x 10(-6) M, respectively. The proposed method was applied to the determination of PHMB-HCl in some contact-lens detergents.

Development of lightweight concrete subfloor with ethylene vinyl acetate (EVA) aggregates waste to reduce impact sound in flooring system

OpenAIRE

Pacheco, Fernanda; Krumenauer, Marcelo; Reis de Medeiros, Daniel; Oliveira, Maria Fernanda; Fonseca Tutikian, Bernardo

2017-01-01

Abstract Comfort and habitability are requirements for housing quality, affected by underfloor system. Thus, this study aims to design lightweight concrete slabs underfloor with the use of ethylene vinyl acetate (EVA) aggregates, with two grain sizes of conventional aggregates replaced with EVA. The experimental counted on four unit mixes, varying the ratio between EVA coarse and fine aggregates and natural aggregates. The underfloor plates were molded with thickness of 3, 5 and 7 centimeters...

Antibacterial and wound healing properties of chitosan/poly(vinyl alcohol)/zinc oxide beads (CS/PVA/ZnO).

Science.gov (United States)

Gutha, Yuvaraja; Pathak, Janak L; Zhang, Weijiang; Zhang, Yaping; Jiao, Xu

2017-10-01

Treatment against bacterial infection is crucial for wound healing. Development of cost-effective antibacterial agent with wound healing properties is still in high demand. In this study we aimed to design chitosan/poly(vinyl alcohol)/zinc oxide (CS/PVA/ZnO) beads as novel antibacterial agent with wound healing properties. CS/PVA/ZnO beads were synthesized, and characterized by using XRD, FTIR, SEM, and TEM analysis. Pure chitosan exhibits two peaks at 2θ=10 and 20 and the CS/PVA polymer matrix exhibit the peaks at 2θ=19.7° and another of low intensity at 2θ=11.5°. Pure ZnO shows the characteristic peaks at (100), (002), (101), (102), (110), (103), (200), and (112) that were in good agreement with wurtzite ore having hexagonal lattice structure. The antibacterial activity of CS/PVA/ZnO against Escherichia coli, and Staphylococcus aureus were evaluated with the zone of inhibition method. Antibacterial activity of CS/PVA/ZnO was higher than that of chitosan (CS) and poly(vinyl alcohol (PVA). Hemocompatibility and biocompatibility of CS/PVA/ZnO were tested in in vitro. Wound healing properties of CS/PVA/ZnO were tested in mice skin wound. CS/PVA/ZnO showed strong antimicrobial, wound healing effect, hemocompatibility and biocompatibility. Hence the results strongly support the possibility of using this novel CS/PVA/ZnO material for the anti bacterial and wound healing application. Copyright © 2017 Elsevier B.V. All rights reserved.

Biodegradability of poly(3-hydroxybutyrate) film grafted with vinyl acetate: Effect of grafting and saponification

Science.gov (United States)

Wada, Yuki; Seko, Noriaki; Nagasawa, Naotsugu; Tamada, Masao; Kasuya, Ken-ichi; Mitomo, Hiroshi

2007-06-01

Radiation-induced graft polymerization of vinyl acetate (VAc) onto poly(3-hydroxybutyrate) (PHB) film was carried out. At a degree of grafting higher than 5%, the grafted films (PHB-g-VAc) completely lost the enzymatic degradability that is characteristic of PHB due to the grafted VAc covering the surface of the PHB film. However, the biodegradability of the PHB-g-VAc films was recovered when the films were saponified in alkali solution under optimum conditions. Graft chains of the PHB-g-VAc film reacted selectively to become biodegradable polyvinyl alcohol (PVA). The biodegradability of the saponified PHB-g-VAc film increased rapidly with time.

Biodegradability of poly(3-hydroxybutyrate) film grafted with vinyl acetate: Effect of grafting and saponification

International Nuclear Information System (INIS)

Wada, Yuki; Seko, Noriaki; Nagasawa, Naotsugu; Tamada, Masao; Kasuya, Ken-ichi; Mitomo, Hiroshi

2007-01-01

Radiation-induced graft polymerization of vinyl acetate (VAc) onto poly(3-hydroxybutyrate) (PHB) film was carried out. At a degree of grafting higher than 5%, the grafted films (PHB-g-VAc) completely lost the enzymatic degradability that is characteristic of PHB due to the grafted VAc covering the surface of the PHB film. However, the biodegradability of the PHB-g-VAc films was recovered when the films were saponified in alkali solution under optimum conditions. Graft chains of the PHB-g-VAc film reacted selectively to become biodegradable polyvinyl alcohol (PVA). The biodegradability of the saponified PHB-g-VAc film increased rapidly with time

Characterization of Plasma-Polymerized 4-vinyl pyridine on Poly(Ethylene Terephthalate) film for anti-microbial properties

DEFF Research Database (Denmark)

Jiang, Juan; Winther-Jensen, Bjørn; Kjær, Erik Michael

2005-01-01

As an efficient way to create an anti-bacterial function on polymer surfaces, we have used plasma polymerisation to create a poly-4-vinyl-pyridine coating on the surface of a common polymer, PET, a polymerisation process that we have shown also works well on several other polymers. We have found....... The mechanical strength of the bond between the substrate and the surface layer has been tested by several methods, and the antibacterial effect of the surface layer with and without silver nano particles has been estimated by measuring electrical resistance as a function of time. The bacteria investigated were...

Preparation and characterization of acrylic acid-grafted poly (vinyl alcohol) hydrogel actuators using γ-ray irradiation

International Nuclear Information System (INIS)

An, Sung Jun; Lim, Youn Mook; Gwon, Hui Jeong; Kim, Yun Hye; Youn, Min Ho; Nho, Young Chang; Han, Dong Hyun; Kim, Chong Yeal

2008-01-01

Active polymer gels expand and contract in response to certain environmental stimuli, such as the application of an electric field or a change in the pH level of the surroundings. This ability to achieve large, reversible deformations with no external mechanical loading has generated much interest in the use of these gels as biomimetic actuators and artificial muscles. In this study, poly (vinyl alcohol)(PVA) grafted acrylic acid monomer (PVA-g-AAc) hydrogels were prepared by 60 Co γ-ray irradiation and their properties such as degree of grafting and weight swelling in electrostimulation as an artificial muscle and actuator were investigated

Fabrication of α-chitin whisker-reinforced poly(vinyl alcohol) nanocomposite nanofibres by electrospinning

International Nuclear Information System (INIS)

Junkasem, Jirawut; Rujiravanit, Ratana; Supaphol, Pitt

2006-01-01

The present contribution reports, for the first time, the successful fabrication of α-chitin whisker-reinforced poly(vinyl alcohol) (PVA) nanocomposite nanofibres by electrospinning. The α-chitin whiskers were prepared from α-chitin flakes from shrimp shells by acid hydrolysis. The as-prepared chitin whiskers exhibited lengths in the range 231-969 nm and widths in the range 12-65 nm, with the average length and width being about 549 and 31 nm, respectively. Successful incorporation of the chitin whiskers within the as-spun PVA/chitin whisker nanocomposite nanofibres was verified by infrared spectroscopic and thermogravimetric methods. The incorporation of chitin whiskers within the as-spun nanocomposite fibre mats increased the Young's modulus by about 4-8 times over that of the neat as-spun PVA fibre mat

A study of poly(vinyl alcohol thermal degradation by thermogravimetry and differential thermogravimetry

Directory of Open Access Journals (Sweden)

Julián Esteban Barrera

2007-05-01

Full Text Available The thermal degradation of poly(vinyl alcohol (PVA having different degrees of hydrolysis and molecular weights was studied by thermogravimetry (TGA and differential thermogravimetry (DTGA. Four degradation events were identified whose intensity was related to the degree of hydrolysis. It was verified that the solid-state degradation mechanism for high hydrolysis degrees corresponded to eliminating water-forming side groups in stoichiometric amounts. The presence of acetate groups and lower melting points delayed the polymer’s thermal decomposition at lower hydrolysis degrees. There was no direct correlation in these samples between weight-loss during the first degradation event and the stoichiometric quantities which would be produced by eliminating the side groups. Reaction order and energy activation value qualitative coincidence was found by evaluating experimental data by using Freeman-Carroll and Friedman kinetic models.

Preparation and characterization of intrinsically coloured polymers using high energy radiation induced processes

International Nuclear Information System (INIS)

Guthrie, J.T.

1978-07-01

Information on the development in research is given in the utilization of high energy radiation sources in polymerizations and on polymer characterization in the following three areas: studies on the nitrile-styrene system, studies on the radiation induced polymerization of 2-vinyl anthraquinone and the graft polymerization of vinyl monomers onto cellulose in the DMSO/HCHO/cellulose system. Within the framework of research in radiation induced polymerization, samples of 2-vinyl anthraquinone were subjected to X-ray diffraction and e.s.r. examinations and the kinetics and mechanism of γ-ray induced solution polymerization of 2-vinyl anthraquinone in methylene chloride and dimethyl sulfoxide was investigated. Methylene chloride was found to be an efficient solvent for poly(2-vinyl anthraquinone). The rate of polymerization in methylene chloride was 10 3 times greater than that obtained using dimethyl sulfoxide as solvent

Polyurethane/poly(vinyl alcohol hydrogel coating improves the cytocompatibility of neural electrodes

Directory of Open Access Journals (Sweden)

Mei Li

2015-01-01

Full Text Available Neural electrodes, the core component of neural prostheses, are usually encapsulated in polydimethylsiloxane (PDMS. However, PDMS can generate a tissue response after implantation. Based on the physicochemical properties and excellent biocompatibility of polyurethane (PU and poly(vinyl alcohol (PVA when used as coating materials, we synthesized PU/PVA hydrogel coatings and coated the surface of PDMS using plasma treatment, and the cytocompatibility to rat pheochromocytoma (PC12 cells was assessed. Protein adsorption tests indicated that the amount of protein adsorption onto the PDMS substrate was reduced by 92% after coating with the hydrogel. Moreover, the PC12 cells on the PU/PVA-coated PDMS showed higher cell density and longer and more numerous neurites than those on the uncoated PDMS. These results indicate that the PU/PVA hydrogel is cytocompatible and a promising coating material for neural electrodes to improve their biocompatibility.

Replacement of Poly(vinyl pyrrolidone) by Thiols: A Systematic Study of Ag Nanocube Functionalization by Surface-Enhanced Raman Scattering

OpenAIRE

Moran, Christine H.; Rycenga, Matthew; Zhang, Qiang; Xia, Younan

2011-01-01

In this work, we used surface-enhanced Raman scattering (SERS) to monitor the replacement of poly(vinyl pyrrolidone) (PVP) on Ag nanocubes by cysteamine, thiol-terminated PEG, and benzenedithiol. PVP is widely used as a colloidal stabilizer and capping agent to control the shape of Ag (as well as many other noble metals) nanocrystals during synthesis, and to stabilize the final colloidal suspension. However, the surface chemistry of Ag nanocrystals often needs to be tailored for specific appl...

PREPARATION AND CHARACTERIZATION OF COMPOSITES COMPRISING MODIFIED HARDWOOD AND WOOD POLYMERS/POLY(VINYL CHLORIDE

Directory of Open Access Journals (Sweden)

Ruxanda Bodîrlău

Full Text Available Chemical modification of hardwood sawdust from ash-tree species was carried out with a solution of maleic anhydride in acetone. Wood polymers, lignin, and cellulose were isolated from the wood sawdust and modified by the same method. Samples were characterized by Fourier transform infrared spectroscopy (FTIR, providing evidence that maleic anhydride esterifies the free hydroxyl groups of the wood polymer components. Composites comprising chemically modified wood sawdust and wood polymers (cellulose, lignin-as variable weight percentages-, and poly (vinyl chloride were obtained and further characterized by using FTIR spectroscopy and scanning electron microscopy (SEM. The thermal behavior of composites was investigated by using the thermogravimetric analysis (TGA. In all cases, thermal properties were affected by fillers addition.

Ester Sensing with Poly (Aniline-co-m-aminobenzoic Acid Deposited on Poly (Vinyl Alcohol

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S. ADHIKARI

2011-02-01

Full Text Available Poly (aniline-co-m-aminobenzoic acid was deposited on poly (vinyl alcohol film by in situ oxidative polymerization of the monomers aniline and m-aminobenzoic acid. Sensing experiments were performed on the composite film with the injection of various concentrations of hexenyl acetate and hexenyl butyrate at room temperature. The sensor responded rapidly and reversibly in the presence of hexenyl acetate and hexenyl butyrate vapors which was detected by resistance change of the composite film upon exposure to the vapor. Selectivity tests revealed that the sensor selectively responded to hexenyl butyrate compared to hexenyl acetate. The sensing response has been explained on the basis of FT-IR spectroscopic analysis of the polymer film before and after exposure to the ester vapor.

Preparation and study of poly vinyl alcohol/hyperbranched polylysine fluorescence fibers via wet spinning

Science.gov (United States)

Lu, Hongwei; Zou, Liming; Xu, Yongjing; Sun, Hong; Li, Yan Vivian

2018-02-01

A simple method of using wet spinning was found effective in the preparation of photoluminescent poly vinyl alcohol (PVA)/hyperbranched polylysine (HBPL) fibers. The photoluminescence of the PVA/HBPL fibers was significantly uniform and the unique uniformity was obtained by controlling the mass ratio of PVA to HBPL in aqueous solutions used in the wet spinning process. The high solubility of HBPL in water make it feasible to well control in the mass ratio of PVA to HBPL, which facilitated the formation of a unique PVA/HBPL mixture, resulting in the fabrication of homogeneous PVA composite fluorescence fibers. The composite fibers exhibit good mechanical, and thermal properties that make the PVA/HBPL fluorescent fibers a great material potentially used in fluorescence applications including optics, imaging and detection.

Self-assembled hemocompatible coating on poly (vinyl chloride) surface

Energy Technology Data Exchange (ETDEWEB)

Zha Zhengbao; Ma Yan; Yue Xiuli; Liu Meng [Nanobiotechnology Division, State Key Laboratory of Urban Water Resources and Environment, School of Sciences, Harbin Institute of Technology, Harbin 150001 (China); Dai Zhifei, E-mail: zhifei.dai@hit.edu.cn [Nanobiotechnology Division, State Key Laboratory of Urban Water Resources and Environment, School of Sciences, Harbin Institute of Technology, Harbin 150001 (China)

2009-11-15

A stable hemocompatible coating was fabricated by consecutive alternating adsorption of iron (III) and two kinds of polysaccharides, heparin (Hep) and dextran sulfate (DS), onto poly (vinyl chloride) (PVC) surfaces via electrostatic interaction. The fluctuation of contact angles with the alternative deposition of iron (III) and polysaccharides verified the progressive buildup of the mulitilayer coating onto the PVC surface. Atomic force microscopy (AFM) analysis revealed that the PVC surfaces were completely masked by iron-polysaccharides multilayer coatings. The activated partial thromboplastin time (APTT) assay showed that both Hep/Fe{sup 3+}/Hep and DS/Fe{sup 3+}/Hep coated PVC were less thrombogenic than the uncoated one. Chromogenic assay for heparin activity proved definitively that the inhibition of locally produced thrombin was ascribed to the thromboresistance of the surface-bound heparin. Compared with the unmodified PVC surfaces, iron-polysaccharide multilayer coating presented a drastically reduced adhesion in vitro of platelets, polymorphonuclear neutrophil leukocytes (PMN) and peripheral blood mononuclear cells (PBMC). Interestingly, the DS/Fe{sup 3+}/Hep coating was found to exhibit higher hydrophilicity and stability, hence lower non-specific protein adsorption in comparison with Hep/Fe{sup 3+}/Hep coating due to the incorporation of dextran sulfate into the multilayer coating.

DC conduction mechanism and dielectric properties of Poly (methyl methacrylate)/Poly (vinyl acetate) blends doped and undoped with malachite green

International Nuclear Information System (INIS)

Abd-El Kader, F.H.; Osman, W.H.; Hafez, R.S.

2013-01-01

Cast thin films of Poly (methyl methacrylate)/Poly (vinyl acetate) blends of different concentrations undoped and doped with malachite green have been prepared and subjected to both dc electrical conduction and dielectric spectroscopy measurements. The analysis of dc electrical conduction data showed that the space charge limited current mechanism has been dominant for Poly (vinyl acetate) while Schottky-Richardson conduction mechanism prevailed for the Poly (methyl methacrylate) and blended samples. The values of field lowering constant β and the thermal activation energy ΔE involved in the dc conduction were reported, which provide another support for the suggested Schottky-Richardson mechanism. The increase in current for the blend sample doped with malachite green has been attributed to the formation of charge transfer complexes inside the polyblend matrix. The dielectric constant as a function of temperature for all samples have been calculated which are affected by the composition ratio and the addition of dye. The relaxation peak that appeared in the dielectric loss curve at 347 K for the doped blend sample is related to local dipoles that are present in the dye material. The obtained relaxation process spectra present in the investigated samples were analyzed with the well-known model of Havriliak-Negami.

Investigation of Complexation of Linear Poly(N-vinyl-2-pyrrolidone) with Poly(methacrylic acid-co-methyl methacrylate) Gel

OpenAIRE

Liu, Guoqin; Yan, Guojin; Zou, Wenjun; Li, Zhengxin

2011-01-01

The contraction of poly(methacrylic acid-co-methyl methacrylate) (P(MAA-co-MMA)) gel induced by complexation with linear poly(N-vinyl-2-pyrrolidone) (PVP) is quite different from that of poly(acrylic acid) (PAA) or poly(methacrylic acid) (PMAA) gel. It was found that the concentration of PVP has a strong effect on the complexation with P(MAA-co-MMA) gel. When PVP was introduced into the P(MAA-co-MMA) network, its dynamic mechanic properties vary greatly between complexed and uncomplexed netwo...

Studies on physical properties and fractography of electron beam irradiated poly(vinyl chloride)/epoxidized natural rubber blend in the presence of trimethylolpropane triacrylate

International Nuclear Information System (INIS)

Chantara Thevy Ratnam; Khairul Zaman Mohd Dahlan; Nasir, M.; Baharin, A.

2000-01-01

The effect of irradiation on the 50/50 poly(vinyl chloride)/epoxidized natural rubber blend was studied in the presence of 3 phr trimethylolpropane triacrylate (TMPTA). The blend was irradiated by using a 3.0 MeV electron beam machine at doses ranging from 20 to 200 kGy in air and room temperature. The tensile properties, resilience and gel fractions of the blends were measured. Electron beam irradiation of the blend in the presence of the TMPTA were found to cause crosslinking which in effect caused an enhancement in modulus and gel fraction together with a concomitant decline in ultimate elongation. The irradiation has resulted in a less hysteretic poly(vinyl chloride)/epoxidized natural rubber blend, with increased rebound resilience. The tensile strength of the blend reached a maximum at 60 kGy followed by a slight decrease at higher doses, implying embrittlement due to the excessive crosslinking. The scanning electron micrographs of the fracture surfaces of the irradiated blends show evidence consistent with the above contention. (Author)

Cytotoxicity of S-conjugates of the sevoflurane degradation product fluoromethyl-2,2-difluoro-1-(trifluoromethyl) vinyl ether (Compound A) in a human proximal tubular cell line

International Nuclear Information System (INIS)

Altuntas, T. Gul; Zager, Richard A.; Kharasch, Evan D.

2003-01-01

Fluoromethyl-2,2-difluoro-1-(trifluoromethyl)vinyl ether (FDVE) is a fluorinated alkene formed by degradation of the volatile anesthetic sevoflurane in anesthesia machines. FDVE is nephrotoxic in rats but not humans. Rat FDVE nephrotoxicity is attributed to FDVE glutathione conjugation and bioactivation of subsequent FDVE-cysteine S-conjugates, in part by renal β-lyase. Although FDVE conjugation and metabolism occur in both rats and humans, the mechanism for selective toxicity in rats and lack of effect in humans is incompletely elucidated. This investigation measured FDVE S-conjugate cytotoxicity in cultured human proximal tubular HK-2 cells, and compared this with known cytotoxic S-conjugates. HK-2 cells were incubated with FDVE and its GSH, cysteine S-mercapturic acid, cysteine S-sulfoxide, and mercapturic acid sulfoxide conjugates (0.1-2.7 mM) for 24 h. Cytotoxicity was determined by lactate dehydrogenase (LDH) release, total LDH, and the ability of viable cells to reduce a tetrazolium-based compound (MTT). FDVE was cytotoxic only at concentrations ≥0.9 mM. No increase in LDH release was observed with either FDVE-GSH conjugate. The FDVE-cysteine conjugates S-(1,1-difluoro-2-fluoromethoxy-2-(trifluoromethyl) ethyl)-L-cysteine (DFEC) and (Z)-S-(1-fluoro-2-fluoromethoxy-2-(trifluoromethyl) vinyl)-L-cysteine ((Z)-FFVC) caused significant differences in LDH release and MTT reduction only at 2.7 mM; (Z)-FFVC was slightly more cytotoxic. Both S-(1,1-difluoro-2-fluoromethoxy-2-(trifluoromethyl) ethyl)-L-cysteine sulfoxide (DFEC-SO) and (Z)-N-acetyl-S-(1-fluoro-2-fluoromethoxy-2-(trifluoromethyl) vinyl)-L-cysteine sulfoxide ((Z)-N-Ac-FFVC-SO) caused slightly greater changes in LDH release or total LDH than the corresponding equimolar DFEC and (Z)-N-acetyl-S-(1-fluoro-2-fluoromethoxy-2-(trifluoromethyl) vinyl)-L-cysteine ((Z)-N-Ac-FFVC) conjugates. In contrast to FDVE S-conjugates, S-(1,2-dichlorovinyl)-L-cysteine was markedly cytotoxic, at concentrations as low as 0

High Pressure Diels Alder Reactions of 1-Vinyl-2,2,6-trimethylcyclohexene Catalyzed by Chiral Lewis Acids; An Enantioselective Route to a Drimane Sesquiterpene Precursor.

NARCIS (Netherlands)

Knol, Joop; Meetsma, Auke; Feringa, Bernard

1995-01-01

The Diels Alder reaction of 1-vinyl-2,2,6-trimethylcyclohexene and 3-((E)-3-(methoxycarbonyl)propenoyl)-1,3-oxazolidin-2-one under high pressure, catalyzed by a chiral bis-imine copper(II) complex, yields a drimane sesquiterpene precursor in a highly regio- and diastereoselective manner with

Role of electrolytes in the preparation of nanoparticles via the emulsion polymerization of vinyl pivalate.

Science.gov (United States)

Kikuchi, Kenji; Kitawaki, Mayuka; Suzuki, Atsushi; Oku, Takeo

2009-10-15

By controlling both the kind of ion and the ionic strength of electrolytes in an emulsion polymerization system of vinyl pivalate containing about 1% sodium lauryl sulfate as a surfactant, nanoparticles of polyvinylpivalate having a diameter of about 25 nm were successfully prepared. The use of high concentrations of lithium chloride and lithium sulfate (approximately 1.0 mol L(-1)) prevented the nanoparticles from aggregating and produced nanoparticles sizes of 25-50 nm. Ammonium acetate and sodium acetate, on the other hand, accelerated the aggregate of the nanoparticles. These phenomena were examined in detail and found to be similar to the Hofmeister phenomena and the combination rule proposed by Craig et al.

Evaluation of the Webler-Brown model for estimating tetrachloroethylene exposure from vinyl-lined asbestos-cement pipes

Directory of Open Access Journals (Sweden)

Heeren Timothy C

2008-06-01

Full Text Available Abstract Background From May 1968 through March 1980, vinyl-lined asbestos-cement (VL/AC water distribution pipes were installed in New England to avoid taste and odor problems associated with asbestos-cement pipes. The vinyl resin was applied to the inner pipe surface in a solution of tetrachloroethylene (perchloroethylene, PCE. Substantial amounts of PCE remained in the liner and subsequently leached into public drinking water supplies. Methods Once aware of the leaching problem and prior to remediation (April-November 1980, Massachusetts regulators collected drinking water samples from VL/AC pipes to determine the extent and severity of the PCE contamination. This study compares newly obtained historical records of PCE concentrations in water samples (n = 88 with concentrations estimated using an exposure model employed in epidemiologic studies on the cancer risk associated with PCE-contaminated drinking water. The exposure model was developed by Webler and Brown to estimate the mass of PCE delivered to subjects' residences. Results The mean and median measured PCE concentrations in the water samples were 66 and 0.5 μg/L, respectively, and the range extended from non-detectable to 2432 μg/L. The model-generated concentration estimates and water sample concentrations were moderately correlated (Spearman rank correlation coefficient = 0.48, p Conclusion PCE concentration estimates generated using the Webler-Brown model were moderately correlated with measured water concentrations. The present analysis suggests that the exposure assessment process used in prior epidemiological studies could be improved with more accurate characterization of water flow. This study illustrates one method of validating an exposure model in an epidemiological study when historical measurements are not available.

Effect of the addition of sugar cane bagasse fibers in the composite with the copolymer vinyl ethylene-acetate (EVA) by solid state NMR

International Nuclear Information System (INIS)

Stael, Giovanni Chaves; D'Almeida, Jose Roberto Moraes; Menezes, Sonia M.C. de; Tavares, Maria Ines Bruno

1997-01-01

Natural fibers composites obtained form sugar cane bagasse and ethylene-vinyl-acetate copolymer were prepared with different compositions and analysed by solid state Carbon-13 NMR aiming the observation of molecular mobility, compatibility, and chemical structure of the different obtained composites. One objective of this work was to enable the future commercial application of these materials

Palladium-Catalyzed Atom-Transfer Radical Cyclization at Remote Unactivated C(sp3 )-H Sites: Hydrogen-Atom Transfer of Hybrid Vinyl Palladium Radical Intermediates.

Science.gov (United States)

Ratushnyy, Maxim; Parasram, Marvin; Wang, Yang; Gevorgyan, Vladimir

2018-03-01

A novel mild, visible-light-induced palladium-catalyzed hydrogen atom translocation/atom-transfer radical cyclization (HAT/ATRC) cascade has been developed. This protocol involves a 1,5-HAT process of previously unknown hybrid vinyl palladium radical intermediates, thus leading to iodomethyl carbo- and heterocyclic structures. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

NMR study of temperature-induced phase separation and polymer-solvent interactions in poly(vinyl methyl ether)/D.sub.2./sub.O/ethanol solutions

Czech Academy of Sciences Publication Activity Database

Hanyková, L.; Labuta, J.; Spěváček, Jiří

2006-01-01

Roč. 47, č. 17 (2006), s. 6107-6116 ISSN 0032-3861 Grant - others:GA UK 294/2004/B Institutional research plan: CEZ:AV0Z40500505 Keywords : poly(vinyl methyl ether)/D2O/ ethanol solutions * temperature-induced phase separation * 1H and 13C NMR spectroscopy Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.773, year: 2006

Fabrication and characterization of a novel hydrophobic CaCO{sub 3} grafted by hydroxylated poly(vinyl chloride) chains

Energy Technology Data Exchange (ETDEWEB)

Bao, Lixia [State Key Laboratory of Polymer Materials Engineering, Sichuan University (China); School of Chemical Science and Technology, Yunnan University (China); Yang, Simei; Luo, Xin [School of Chemical Science and Technology, Yunnan University (China); Lei, Jingxin [State Key Laboratory of Polymer Materials Engineering, Sichuan University (China); Cao, Qiue [School of Chemical Science and Technology, Yunnan University (China); Wang, Jiliang, E-mail: jlwang@ynu.edu.cn [School of Chemical Science and Technology, Yunnan University (China)

2015-12-01

Highlights: • Hydroxylated poly(vinyl chloride) (PVC-OH) with different molecular weight and hydroxyl value was successfully prepared by the suspension copolymerization. • PVC-OH was grafted onto the surface of CaCO{sub 3} particles by the urethane formation reaction. • The modified CaCO{sub 3} particles show excellent hydrophobicity. - Abstract: The hydroxylated PVC (PVC-OH) was successfully synthesized by a suspension polymerization of vinyl chloride (VC), butyl acrylate (BA) and hydroxyethyl acrylate (HEA). Novel hydrophobic CaCO{sub 3} was then prepared by a urethane formation reaction between methylene diphenyl diisocyanate (MDI) and the −OH groups both in the PVC-OH chains and on the surface of pristine CaCO{sub 3} particles. The effect of the PVC-OH content on the grafting ratio of treated CaCO{sub 3} particles was extensively investigated. Combining the result of Fourier transform infrared (FTIR) with that of water contact angle, it can be concluded that the hydrophobicity of CaCO{sub 3} had been efficiently improved by the PVC-OH segments grafted on the surface of CaCO{sub 3} particles. X-ray diffraction (XRD), thermal gravity analysis (TGA), scanning electron microscope (SEM) and transmission electron microscope (TEM) were also used to study crystalline behaviors, thermal stability and surface morphology of the modified CaCO{sub 3} particles, respectively. The change of specific surface area implying surface modification was investigated as well.

Tailoring of poly(vinyl alcohol cryogels properties by salts addition

Directory of Open Access Journals (Sweden)

2009-05-01

Full Text Available The present paper aims to study the possibility to modify the properties of poly(vinyl alcohol (PVA hydrogels prepared in the presence of different salt types (Na2SO4, NaCl and NaNO3 in order to extend the nature of the salts already used in obtaining films or gels, to expand their concentration domains and to explain the increase of film strain, concomitantly with the increase of their crystallinity. The morphology of the PVA based hydrogels has been studied by Scanning Electronic Microscopy (SEM, the interaction between the PVA macromolecular chains and salts has been determined by Fourier Transform Infrared Spectroscopy (FTIR, while the mechanical properties of the cryogels have been investigated by oscillatory dynamic mechanical measurements. The gels swelling in water have been monitored by gravimetric method in order to evidence the alteration of the PVA cryogel properties such as crystallinity and porosity determined by the salt addition to the initial PVA aqueous solution. The data reported show that the ions present in the PVA solution influence the interaction between PVA-water and PVA-PVA chains; their influence on the salt-based PVA hydrogels follow the Hofmeister lyotropic series.

A comparative study of thermal and mechanical stabilities of gamma irradiated ethylene-ethyl acrylate and ethylene-vinyl acetate copolymers

International Nuclear Information System (INIS)

Sen, M.; Gueven, O.

1995-01-01

Ethylene-ethyl acrylate and Ethylene-vinyl acetate copolymers were irradiated in ambient conditions with γ-rays. The influence of the chain scission, crosslinking and relative changes in crystallinity on the thermal and mechanical properties were investigated and a correlation has been tried to find between the thermal and mechanical stabilities of copolymers. For the two copolymers, among various mechanical properties evaluated, the best correlation was found between the toughness (energy to break point) and the time required for 10% weight loss. (Author)

Tuning the nano/micro-structure and properties of melt-processed ternary composites of polypropylene/ethylene vinyl acetate blend and nanoclay: The influence of kinetic and thermodynamic parameters

CSIR Research Space (South Africa)

Mofokeng, Tladi G

2017-09-01

Full Text Available The present study reports the dependence of the nano/micro-structure and properties of polypropylene (PP)/ethylene vinyl acetate (EVA)/nanoclay ternary composites on the kinetics and thermodynamics of the melt-mixing process. The size of dispersed...

Kinetics of vinyl acetate emulsion polymerization in a pulsed tubular reactor: comparison between experimental and simulation results

Directory of Open Access Journals (Sweden)

Sayer C.

2002-01-01

Full Text Available A new reactor, the pulsed sieve plate column (PSPC, was developed to perform continuous emulsion polymerization reactions. This reactor combines the enhanced flexibility of tubular reactors with the mixing behavior provided by sieved plates and by the introduction of pulses that is important to prevent emulsion destabilization. The main objective of this work is to study the kinetics of vinyl acetate (VA emulsion polymerization reactions performed in this PSPC. Therefore, both experimental studies and reaction simulations were performed. Results showed that it is possible to obtain high conversions with rather low residence times in the PSPC.

Copper-Mediated Formation of Aryl, Heteroaryl, Vinyl and Alkynyl Difluoromethylphosphonates: A General Approach to Fluorinated Phosphate Mimics.

Science.gov (United States)

Ivanova, Maria V; Bayle, Alexandre; Besset, Tatiana; Poisson, Thomas; Pannecoucke, Xavier

2015-11-02

A general and efficient access to aryl, heteroaryl, vinyl and alkynyl difluoromethylphosphonates is described. The developed methodology using TMSCF2PO(OEt)2, iodonium salts and a copper salt provided a straightforward manifold to reach these highly relevant products. The reaction proved to be highly functional group tolerant and proceeded under mild conditions, giving the corresponding products in good to excellent yields. This method represents the first general synthetic route to this important class of fluorinated scaffolds, which are well-recognized as in vivo stable phosphate surrogates. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of Saponification Rate on Electrooptical Properties and Morphology of Poly(vinyl alcohol)/Liquid Crystal Composite Films

Science.gov (United States)

Ono, Hiroshi; Kawatsuki, Nobuhiro

1995-03-01

The relationship between the saponification rate of poly(vinyl alcohol) (PVA), and the electrooptical properties and morphology of the PVA/liquid crystal (LC) composite films was investigated. Light transmission clazing and the LC droplet size were varied by changing the saponification rate or the blend ratio of two kinds of PVA with different saponification rates because the refractive index and surface tension could be controlled by the saponification rate of PVA. The threshold voltage decreased with increasing saponification rate though the extrapolation length was decreased. It was suggested that the electrooptical properties were strongly dependent on the droplet size.

Removal of some basic dyes by poly (Vinyl Alcohol/ acrylic acid)Hydrogel

International Nuclear Information System (INIS)

Hegazy, S.A.; Abdel-AAl, S.E.; Abdel-Rehim, H.A.; Khalifa, N.A.; El-Hosseiny, E.M.

2000-01-01

A study has made on the preparation and properties of poly (vinyl alcohol/ acrylic acid) hydrogel for the purpose of removal of cationic dyes from aqueous solutions. The effect of dose and monomer concentration on the uptake property of the hydrogel toward dye was studied. The uptake of basic methylene blue-9 dye with PVA/AAc was studied by the batch adsorption technique. The effect of pH on the dye uptake was demonstrated to find out that the suitable pH for maximum uptake occurred at pH 5. It was observed that as the concentration of dye is increased the dye uptake decreased. Furthermore, the uptake of dye by hydrogels increased as the temperature was elevated. The recovery of dye adsorbed is possible by treating the hydrogel with 5% HCl. The results obtained suggested this hydrogel possessed good removal properties towards basic methylene blue-9 dye, and this suggests that such hydrogels could be acceptable for practical uses

Thermal, mechanical and dielectric properties of poly(vinyl alcohol)/graphene oxide composites

Science.gov (United States)

Rathod, Sunil G.; Bhajantri, R. F.; Ravindrachary, V.; Pujari, P. K.; Sheela, T.; Naik, Jagadish

2014-04-01

In this work the composite films of poly(vinyl alcohol) (PVA) doped with functionalized Graphene Oxide (GO) were prepared by solution casting method. The films were characterized using FT-IR, DSC, XRD, mechanical properties and dielectric studies at room temperature. FTIR spectra shows the formation of hydrogen bonds between hydroxyl groups of PVA and the hydroxy groups of GO. The DSC thermograms shows the addition of GO to PVA greatly improves the thermal stability of the composites. XRD patterns shows that the GO exfoliated and uniformly dispersed in PVA matrix. Mechanical properties are significantly improved in PVA/GO composites. The tensile strength increased from 8.2 to 13.7 MPa and the Young's modulus increased from 7.5 to 24.8 MPa for 5 wt% GO doped sample. Dielectric spectroscopy showed a highest dielectric constant for the 5 wt% GO doped PVA films. This work provides a potential design strategy on PVA/GO composite, which would lead to higher-performance, flexible dielectric materials, high charge-storage devices.

Production and Characterization of a New Bacterial Cellulose/Poly(Vinyl Alcohol Nanocomposite

Directory of Open Access Journals (Sweden)

Miguel Gama

2013-05-01

Full Text Available Bacterial cellulose (BC is characterized for its high water holding capacity, high crystallinity, an ultrafine fiber network and high tensile strength. This work demonstrates the production of a new interpenetrated polymer network nanocomposite obtained through the incorporation of poly(vinyl alcohol (PVA on the BC matrix and evaluates the effect of oven drying on the morphological, mechanical and mass transfer properties of the composite membranes. Both the addition of PVA and oven drying induce the appearance of larger pores (circa 1–3 µm in average diameter in dried BC/PVA membranes. Both types of treatments also affect the permeability of the composite, as assessed by the diffusion coefficients of polyethylene glycol (PEG molecules (900, 8,000, 35,000 and 100,000 Da across the membranes. Finally, the Young’s modulus of dry pristine BC decreases following PVA incorporation, resulting in a change from 3.5 GPa to 1 GPa and a five-fold loss in tensile strength.

The Preparation of Graphene Reinforced Poly(vinyl alcohol Antibacterial Nanocomposite Thin Film

Directory of Open Access Journals (Sweden)

Yuan-Cheng Cao

2015-01-01

Full Text Available Methylated melamine grafted polyvinyl benzylchloride (mm-g-PvBCl was prepared which was used as additive in poly(vinyl alcohol (PVA and graphene nanosheets (GNs were used to reinforce the mechanical strength. Using casting method, antimicrobial nanocomposite films were prepared with the polymeric biocide loading lever of 1 wt%, 5 wt%, and 10 wt%. Thermogravimetric analysis (TGA characterization revealed the 2.0 wt% of graphene content in resultant nanocomposites films. XRD showed that the resultant GNs 2 theta was changed from 16.6 degree to 23.3 degree. Using Japanese Industry Standard test methods, the antimicrobial efficiency for the loading lever of 1 wt%, 5 wt%, and 10 wt% was 92.0%, 95.8%, and 97.1%, respectively, against gram negative bacteria E. coli and 92.3%, 99.6%, and 99.7%, respectively, against the gram positive S. aureus. These results indicate the prepared nanocomposite films are the promising materials for the food and drink package applications.

Biodegradable starch/poly (vinyl alcohol) film reinforced with titanium dioxide nanoparticles

Science.gov (United States)

Hejri, Zahra; Seifkordi, Ali Akbar; Ahmadpour, Ali; Zebarjad, Seyed Mojtaba; Maskooki, Abdolmajid

2013-10-01

Biodegradable starch/poly (vinyl alcohol)/nano-titanium dioxide (ST/PVA/nano-TiO2) nanocomposite films were prepared via a solution casting method. Their biodegradability, mechanical properties, and thermal properties were also studied in this paper. A general full factorial experimental approach was used to determine effective parameters on the mechanical properties of the prepared films. ST/PVA/TiO2 nanocomposites were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results of mechanical analysis show that ST/PVA films with higher contents of PVA have much better mechanical properties. In thermal analysis, it is found that the addition of TiO2 nanoparticles improves the thermal stability of the films. SEM micrographs, taken from the fracture surface of samples, illustrate that the addition of PVA makes the film softer and more flexible. The results of soil burial biodegradation indicate that the biodegradability of ST/PVA/TiO2 films strongly depends on the starch proportion in the film matrix. The degradation rate is increased by the addition of starch in the films.