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1

Effect of poly(vinyl acetate) (PVAc) on thermal behavior and mechanical properties of poly(3-hydroxybutyrate)\\/poly(propylene carbonate) (PHB\\/PPC) blends  

Microsoft Academic Search

To assess the compatibility of blends of synthetic poly(propylene carbonate) (PPC), with a natural bacterial poly(3-hydroxybutyrate) (PHB), a simple casting procedure of blend was used. poly(3-hydroxybutyrate)\\/poly(propylene carbonate) blends are found to be incompatible according to DSC and DMA analysis. In order to improve the compatibility and mechanical properties of PHB\\/PPC blends, poly(vinyl acetate) (PVAc) was added as a compatibilizer. The

Xiuyan Wang; Shuwen Peng; Lisong Dong

2005-01-01

2

Sisal cellulose whiskers reinforced polyvinyl acetate nanocomposites  

Microsoft Academic Search

Sisal nanowhiskers were used as novel reinforcement to obtain nanocomposites with polyvinyl acetate (PVAc) as matrix phase. They are seen as attractive materials due to the widespread availability and low cost of the sisal source material. Statistical analysis of the sisal whisker length and diameter resulted in average values of 250 nm and 4 nm, respectively, resulting in an average aspect ratio

Nancy Lis Garcia de Rodriguez; Wim Thielemans; Alain Dufresne

2006-01-01

3

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

EPA Science Inventory

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 ...

4

Improving the compressive strengths of cold-mix asphalt using asphalt emulsion modified by polyvinyl acetate  

Microsoft Academic Search

Rut is the type of flexible pavement distress mostly occurring in Mexico, generally caused by exceedingly heavy axle loads. Therefore, the compressive strengths of cold-mix asphalt (CMA) must be improved, for this reason a polyvinyl acetate emulsion (PVAC-E) was added to a cationic quick set emulsified asphalt to obtain a modified asphalt emulsion that was mixed with a local aggregate

L. E. Chávez-Valencia; E. Alonso; A. Manzano; J. Pérez; M. E. Contreras; C. Signoret

2007-01-01

5

Effect of addition of polyvinyl acetate to melamine-formaldehyde resin on the adhesion and formaldehyde emission in engineered flooring  

Microsoft Academic Search

The objective of this research was to investigate the effect of adding polyvinyl acetate (PVAc), for reducing the formaldehyde emission level, on the adhesion properties of melamine-formaldehyde (MF) resin for fancy veneer and plywood in engineered flooring. We controlled the hot-press temperature, time and pressure to determine the bonding strength and formaldehyde emission. Blends of various MF resin\\/PVAc compositions were

Sumin Kim; Hyun-Joong Kim

2005-01-01

6

Microvoids in unsaturated polyester resins containing poly(vinyl acetate) and composites with calcium carbonate and glass fibers  

Microsoft Academic Search

When thermoplastics is added as a low-profile additive (LPA) to an unsaturated polyester (UP) resin, microvoids are introduced and compensate for the high volume shrinkage of the resin. The characteristics and mechanisms involved in the microvoid formation of a low-shrinkage UP resin system with poly(vinyl acetate) (PVAc) as LPA were investigated in this work. Both PVAc and styrene were found

Z. Zhang; S. Zhu

2000-01-01

7

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

PubMed

Tailor-made conjunct of methyl cellulose (MC) and polyvinyl acetate (PVAc) was synthesized through the combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and thiol-ene click reaction. MC was firstly transferred into unsaturated MC (UMC), and then covalently connected with well-defined PVAc obtained by RAFT polymerization of vinyl acetate. The structure of the conjunct polymer (MCV) was confirmed with Fourier transform infrared spectra (FTIR) and proton nuclear magnetic resonance ((1)H NMR). Well-defined MCV was amphiphilic and able to self-assemble into size controllable micelles, which was verified with transmission electron microscopy (TEM) and size distribution analysis. It was found that the mean diameters of the micelles in aqueous solution were 105.6, 96.0 and 75.9 nm when the number average molecular weights of PVAc segments of MCV were 49,300, 32,500 and 18,200, respectively. PMID:23107808

Xiao, Congming; Xia, Cunping

2012-10-26

8

Synthesis of poly(vinyl acetate-methyl methacrylate) copolymer microspheres using suspension polymerization.  

PubMed

Poly(vinyl acetate-methyl methacrylate) (VAc-MMA) copolymer microspheres were prepared using suspension polymerization at low temperature initiated with 2,2'-azobis(2,4-dimethyl valeronitrile) (ADMVN). The poly(VAc-MMA) copolymer microspheres can be used over a large area where homopolymers, polyvinyl acetate (PVAc) and methyl methacrylate (PMMA) microspheres are capable of being put to use. The prepared microspheres were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Obtained copolymer microspheres which have 200 ?m average diameter and higher thermal stability than those of homopolymer. PMID:22137854

Islam, Md Shahidul; Yeum, Jeong Hyun; Das, Ajoy Kumar

2011-11-10

9

Role of the density in the crossover region of o -terphenyl and poly(vinyl acetate)  

NASA Astrophysics Data System (ADS)

The coupling between the reorientation of molecular probes and the density in one low-molar mass glass former [ o -terphenyl (OTP)] and one polymer [poly(vinyl acetate) (PVAc)] is studied in the Goldstein’s crossover region where the structural (?) and the secondary (?) relaxations bifurcate. The coupling is found to be strong in OTP and virtually absent in PVAc. The probes sense both the ? and ? relaxations, and locate their splitting accurately. It is concluded that the density affects the relaxation occurring in the crossover region of OTP but not of PVAc at subnanometer length scales. The findings are compared with recent assessments of the role of the molecular packing close and above the glass transition temperature Tg .

Barbieri, A.; Gorini, G.; Leporini, D.

2004-06-01

10

Poly(ethylene oxide) Dynamics in Blends with Poly(vinyl acetate)  

NASA Astrophysics Data System (ADS)

^2H NMR relaxation measurements were performed to study the segmental dynamics of perdeuteropoly(ethylene oxide) (d4PEO) in miscible blends with poly(vinyl acetate) (PVAc). For two compositions (2% and 50% d4PEO), spin-lattice relaxation times were measured in a temperature range well above Tg. Over the temperature range studied, the segmental dynamics of the PEO component in 2% PEO/PVAc blend is almost the same as that in 3% PEO/PMMA blend reported by Lutz et al. (Macromolecules 2003, 36, 1724-1730), even though the Tg of PVAc is 100K lower than that of PMMA. In the 2% d4PEO blend, the segmental dynamics of PEO is 9 orders of magnitude faster than PVAc segmental dynamics at the blend Tg. For the two compositions studied, segmental dynamics of the PEO component can be well described by L-M model with a self-concentration of 0.3. By comparing the segmental correlation times of the PEO component with viscoelastic shift factors reported by Urakawa et al. (J. Non-Crystalline Solids 352, 2006 5042-5049), it is found that the temperature dependence of the segmental dynamics of the PEO component is weaker than the temperature dependence of the PEO terminal dynamics.

Zhao, Junshu; Ediger, Mark

2007-03-01

11

Study of behaviour on simulated daylight ageing of artists’ acrylic and poly(vinyl acetate) paint films  

Microsoft Academic Search

This work proposes a multi-method approach that combines advanced microscopy (SEM\\/EDX, AFM) and spectroscopy (UV-vis and FTIR)\\u000a techniques. This approach not only characterises the behaviour of the additives of two commercial poly(vinyl acetate) (PVAc)\\u000a and acrylic emulsion paints but also simultaneously characterises the changes in chemical composition and morphology observed\\u000a in the paint films as a result of ageing due

María Teresa Doménech-Carbó; Miguel F. Silva; Elvira Aura-Castro; Laura Fuster-López; Stephan Kröner; María Luisa Martínez-Bazán; Xavier Más-Barberá; Marion F. Mecklenburg; Laura Osete-Cortina; Antonio Doménech; José Vicente Gimeno-Adelantado; Dolores Julia Yusá-Marco

2011-01-01

12

Ionic conductivity of polyelectrolyte derivatives of poly(vinyl alcohol)-lithium ion complex films  

Microsoft Academic Search

Ionic conductivity of various polymeric hybrid complexes made from the polyelectrolytes carboxymethylated poly(vinyl alcohol) (PVAC), poly(vinyl alcohol) acetalized with glyoxylic acid (PVAG) and poly(vinyl alcohol) acetalized with iodine N-methyl-4-pyridyladehyde (PVAP) were investigated. It was found that when the content of carboxyl group in PVAC reaches 5.3% and the content of carboxyl group in PVAG is more than 9.7%, the ion

Guan-Ling Bao; Wel-Qin Yun; Shl-Bi Fang; Ying-Yan Jiang

1987-01-01

13

Electrical Conduction Mechanism and Optical Properties of Polyvinyl Acetate and Cellulose Acetate Propionate Blends  

NASA Astrophysics Data System (ADS)

Films of Polyvinyl acetate (PVAc), cellulose acetate propionate (CAP) homopolymers and their blends of compositions 0.85/0.15, 0.7/0.3, 0.5/0.5, 0.3/0.7 and 0.15/0.85 (wt/wt) were prepared to investigate the type of electrical conduction mechanism. The current-voltage characteristics have been studied under different conditions. Also, ultraviolet/visible spectra of all samples have been studied according to their different composition ratios. The conduction mechanisms at different temperatures and voltage ranges appear to be essentially a space charge limited current for the two individual polymers, while for the blend samples the predominance mechanism is Poole-Frenkel type. Ultraviolet/visible studies of the investigated samples showed that the blend sample of 0.5/0.5 (wt/wt) has the smallest absorption edge (4.58 eV) and highest band tail (0.61 eV). The composition blend sample 0.5/0.5 (wt/wt) has the most proper conduction and optical properties which has attractive attention in the view of its application in electronic and optical devices.

Abd El-Kader, F. H.; Shehap, A. M.; Basha, A. F.; El-Fewaty, N. H.

2011-06-01

14

Properties of hot-melt extruded theophylline tablets containing poly(vinyl acetate).  

PubMed

The objectives of this study were to investigate the properties of poly(vinyl acetate) (PVAc) as a retardant polymer and to study the drug release mechanism of theophylline from matrix tablets prepared by hot-melt extrusion. A physical mixture of drug, polymer, and drug release modifiers was fed into the equipment and heated inside the barrel of the extruder. The cylindrical extrudates were either cut into tablets or ground into granules and compressed with other excipients into tablets. Due to the low glass transition temperature of the PVAc, the melt extrusion process was conducted at approximately 70 degrees C. Theophylline was used as the model drug in this study. Theophylline was present in the extrudate in its crystalline form and was released from the tablets by diffusion. The Higuchi diffusion model and percolation theories were applied to the dissolution data to explain the drug release properties of the matrix systems. The release rate was shown to be dependent on the granule size, drug particle size, and drug loading in the tablets. Water-soluble polymers were demonstrated to be efficient release rate modifiers for this system. PMID:10914317

Zhang, F; McGinity, J W

2000-09-01

15

Li-ion conduction in PVAc based polymer blend electrolytes for lithium battery applications  

Microsoft Academic Search

The present work describes the Li-ion conduction in Poly(vinyl acetate) (PVAc) based polymer blend electrolytes have been synthesized by solvent casting technique for lithium battery applications. Characterization by XRD, SEM, AFM, FTIR, TG\\/DTA and photoluminescence was performed for synthesized polymer electrolytes. The thermal behaviour of the samples was ascertained from differential scanning calorimeter (DSC) and TG\\/DTA. The temperature dependence of

M. Ulaganathan; S. Sundar Pethaiah; S. Rajendran

2011-01-01

16

Electrical and thermal properties of polyvinyl acetal based nanocomposites  

Microsoft Academic Search

A water chemistry procedure is used to synthesize titanium dioxide nanoparticles which can later be blended with a polymer to form a nanodielectric. The synthesized nanoparticles are dispersed in two grades of polyvinyl acetal (commercially available under the trade names BX-L and KS-10, manufactured by SEKISUI Chemicals). Nanocomposite materials were prepared with 15 and 33 wt% titanium dioxide. The variation

G. Polizos; E. Tuncer; Isidor Sauers; David Randy James; A. R. Ellis; Marshall O Pace

2009-01-01

17

Conformational features of poly(1,1-dihydroperfluorooctyl acrylate) and poly(vinyl acetate) diblock oligomers in supercritical carbon dioxide  

NASA Astrophysics Data System (ADS)

We report detailed molecular dynamics calculations of single chain diblocks of poly(1,1- dihydroperfluorooctyl acrylate) (PFOA) and poly(vinyl acetate) (PVAc) in supercritical carbon dioxide, SCCO2. At the critical micelle concentration, this system exhibits self-assembly into micellar structures due to the solvent specific selectivity of the blocks. Although the intermolecular factors determining micelle formation are well studied for this system, the intramolecular single chain conformational features of the molecules have not yet been investigated in the literature. The specific aim of the present work is to study the conformational properties of the single diblock chains in supercritical carbon dioxide at 65 °C, and at four different pressures by molecular dynamics simulations. Fluctuations in the shapes of the PVAc and PFOA blocks are observed to be strongly dependent on pressure. The rate of approach of an initially rodlike chain to its equilibrium conformational space is likewise found to depend strongly on pressure. Calculations of the radial distribution function for the solvent molecules around the chain show that a solvation shell is formed around the polymer. Important correlations between the results of single chain calculations and micelle behavior are observed and discussed.

Baysal, Canan; Erman, Burak; Chu, Benjamin

2001-03-01

18

Nanostructural Features in Silica-polyvinyl Acetate Nanocomposites Characterized by Small-Angle Scattering  

SciTech Connect

Small-angle scattering (SAS) experiments were carried out on nanocomposites of poly(vinyl acetate) (PVAc) and fumed silica nanoparticles with different surface areas and chemical treatment, in the wave-vector (Q) range: 0.0002-1 A-1 . SAS data on composites with matrices of two different molecular weights indicate that the particle aggregation is independent of the molecular weight of the matrix for a fixed filler concentration and surface treatment. Particle size distributions derived from the SAS data suggest that particle aggregation is reduced when the native surface hydroxyl groups are blocked by various surface treatments, which also reduce the bonding strength to the polymer matrix. The unified exponential/power-law analysis of the SAS data shows three levels of hierarchy in the organization of silica particles. The first level consists of small aggregates of silica particles. At the second level we observe polydispersed aggregates resembling mass-fractal objects that is corroborated by TEM. The polydispersed aggregates further associate to form agglomerates at the third level. The relevance of these findings to the mechanism of nanofiller reinforcement of linear amorphous polymers above Tg is discussed.

Raghavan, Aravinda N [ORNL; Thiyagarajan, P. [Argonne National Laboratory (ANL); Zhu, Dr. Ai-Jun [Rensselaer Polytechnic Institute (RPI); Ash, Dr. Benjamin J. [Rensselaer Polytechnic Institute (RPI); Shofner, M. L. [Rensselaer Polytechnic Institute (RPI); Schadler, Linda [Rensselaer Polytechnic Institute (RPI); Kumar, Sanat K [ORNL; Sternstein, S. S. [Rensselaer Polytechnic Institute (RPI)

2007-01-01

19

Nanostructural features in silica-polyvinyl acetate nanocomposites characterized by small-angle scattering.  

SciTech Connect

Small-angle scattering (SAS) experiments were carried out on nanocomposites of poly(vinyl acetate) (PVAc) and fumed silica nanoparticles with different surface areas and chemical treatment, in the wave-vector (Q) range: 0.0002-1 Angstrom{sup -1}. SAS data on composites with matrices of two different molecular weights indicate that the particle aggregation is independent of the molecular weight of the matrix for a fixed filler concentration and surface treatment. Particle size distributions derived from the SAS data suggest that particle aggregation is reduced when the native surface hydroxyl groups are blocked by various surface treatments, which also reduce the bonding strength to the polymer matrix. The unified exponential/power-law analysis of the SAS data shows three levels of hierarchy in the organization of silica particles. The first level consists of small aggregates of silica particles. At the second level we observe polydispersed aggregates resembling mass-fractal objects that is corroborated by TEM. The polydispersed aggregates further associate to form agglomerates at the third level. The relevance of these findings to the mechanism of nanofiller reinforcement of linear amorphous polymers above T{sub g} is discussed.

Narayanan, R. A.; Thiyagarajan, P.; Zhu, A. J.; Ash, J.; Shofner, M. L.; Schadler, L. S.; Kumar, S. K.; Sternstein, S. S.; ORNL; Rensselaer Polytechnic Inst.

2007-09-10

20

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

PubMed Central

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.

Jannesari, Marziyeh; Varshosaz, Jaleh; Morshed, Mohammad; Zamani, Maedeh

2011-01-01

21

Electrical and Thermal Properties of Polyvinyl Acetal Based Nanocomposites  

SciTech Connect

A water chemistry procedure is used to synthesize titanium dioxide nanoparticles which can later be blended with a polymer to form a nanodielectric. The synthesized nanoparticles are dispersed in two grades of polyvinyl acetal (commercially available under the trade names BX-L and KS-10, manufactured by SEKISUI Chemicals). Nanocomposite materials were prepared with 15 and 33 wt% titanium dioxide. The variation of the glass transition temperature with increasing filler weight fraction is presented. The dielectric breakdown strengths of the nanodielectric samples are reported. The presented results can be employed to optimize the dielectric properties of the studied nanocomposites for potential use in cryogenic high voltage applications.

Sauers, Isidor [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL; Tuncer, Enis [ORNL; Polyzos, Georgios [ORNL; Pace, Marshall O [ORNL

2009-10-01

22

Phonon transport in an initially twisted polyvinyl acetate nanofiber  

NASA Astrophysics Data System (ADS)

A reduction in phonon thermal conductivity enhances thermoelectric performance. One method to accomplish this is by applying mechanical stress to a nanostructure. We consider an initially twisted 20 nm polyvinyl acetate nanofiber undergoing torsion. Our analytical method uses the continuum approach of Mooney's model. Torsion modifies the phonon dispersion. Angles of twist between 45° and 70° reduce the averaged phonon group velocity and the phonon thermal conductivity but when these angles are increased further, this conductivity increases. This suggests a phonon engineering approach to tune the thermal conductivity of nanomaterials.

Liangruksa, Monrudee; Puri, Ishwar K.

2013-05-01

23

Morphology of the poly(vinyl alcohol)–poly(vinyl acetate) copolymer in macrodefect-free composites: a 13C magic-angle-spinning nuclear magnetic resonance and 1H spin-diffusion study  

Microsoft Academic Search

A study was made of the macrodefect-free (MDF) composite based on aluminate cement and a poly(vinyl alcohol)–poly(vinyl acetate)\\u000a (PVAc) copolymer by 13C cross-polarization magic-angle-spinning nuclear magnetic resonance. The spectra were run on both the copolymer and the MDF\\u000a composite in order to observe the atomic environments of the carbon nuclei. An analysis of the intramolecular hydrogen bonds\\u000a showed a stronger

ANGIOLINA COMOTTI; ROBERTO SIMONUTTI; PIERO SOZZANI

1997-01-01

24

The distribution of sequences in partially hydrolysed polyvinylic alcohol  

Microsoft Academic Search

The block copolymer structure of partially hydrolysed polyvinyl alcohol was investigated by DSC: This structure was revealed by the dependence of the melting point of crystalline phase against the composition of vinyl alcohol-vinyl acetate copolymers (VOH-VAc) synthesised by different methods. Using the Flory equation, the sequential probabilities pVOH and pVAc representing quantitative values of the sequences distribution along the chain

Iulia Pocsan; Sever Serban; Gheorghe Hubca; Mihai Dimonie; Horia Iovu

1997-01-01

25

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

SciTech Connect

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.

Jia Xin [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology, Lanzhou University, Lanzhou 730000 (China); Department of Chemistry, Hexi University, Zhangye 734000 (China); Li Yanfeng [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology, Lanzhou University, Lanzhou 730000 (China)], E-mail: liyf@lzu.edu.cn; Zhang Bo; Cheng Qiong; Zhang Shujiang [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology, Lanzhou University, Lanzhou 730000 (China)

2008-03-04

26

Dielectric studies of polyvinyl-acetate-based phantom for applications in microwave medical imaging  

Microsoft Academic Search

Phantoms that exhibit complex dielectric properties similar to low water content biological tissues over the electromagnetic spectrum of 2–3 GHz have been synthesized from carbon black powder, graphite powder and polyvinyl-acetate-based adhesive. The materials overcome various problems that are inherent in conventional phantoms such as decomposition and deterioration due to the invasion of bacteria or mold. The absorption coefficients of the

G. Bindu; Anil Lonappan; Vinu Thomas; C. K. Aanandan; K. T. Mathew

2006-01-01

27

Formation Mechanism of a Silane-PVA/PVAc Complex Film on a Glass Fiber Surface.  

PubMed

Mechanical properties of glass fiber reinforced composite materials are affected by fiber sizing. A complex film formation, based on a silane film and PVA/PVAc (polyvinyl alcohol/polyvinyl acetate) microspheres on a glass fiber surface is determined at 1) the nanoscale by using atomic force microscopy (AFM), and 2) the macroscale by using the zeta potential. Silane groups strongly bind through the Si?O?Si bond to the glass surface, which provides the attachment mechanism as a coupling agent. The silane groups form islands, a homogeneous film, as well as empty sites. The average roughness of the silanized surface is 6.5 nm, whereas it is only 0.6 nm for the non-silanized surface. The silane film vertically penetrates in a honeycomb fashion from the glass surface through the deposited PVA/PVAc microspheres to form a hexagonal close pack structure. The silane film not only penetrates, but also deforms the PVA/PVAc microspheres from the spherical shape in a dispersion to a ellipsoidal shape on the surface with average dimensions of 300/600 nm. The surface area value Sa represents an area of PVA/PVAc microspheres that are not affected by the silane penetration. The areas are found to be 0.2, 0.08, and 0.03 ?m(2) if the ellipsoid sizes are 320/570, 300/610, and 270/620 nm for silane concentrations of 0, 3.8, and 7.2 ?g?mL(-1) , respectively. The silane film also moves PVA/PVAc microspheres in the process of complex film formation, from the low silane concentration areas to the complex film area providing enough silane groups to stabilize the structure. The values for the residual silane honeycomb structure heights (Ha ) are 6.5, 7, and 12 nm for silane concentrations of 3.8, 7.2, and 14.3 ?g?mL(-1) , respectively. The pH-dependent zeta-potential results suggest a specific role of the silane groups with effects on the glass fiber surface and also on the PVA/PVAc microspheres. The non-silanized glass fiber surface and the silane film have similar zeta potentials ranging from -64 to -12 mV at pH's of 10.5 and 3, respectively. The zeta potentials for the PVA/PVAc microspheres on the glass fiber surface and within the silane film significantly decrease and range from -25 to -5 mV. The shapes of the pH-dependent zeta potentials are different in the cases of silane groups over a pH range from 7 to 4. A triple-layer model is used to fit the non-silanized glass surface and the silane film. The value of the surface-site density for ?Xglass and ?Xsilane , in which X denotes the Al?O?Si group, differs by a factor of 10(-4) , which suggests an effective coupling of the silane film. A soft-layer model is used to fit the silane-PVA/PVAc complex film, which is approximated as four layers. Such a simplification and compensation of the microsphere shape gives an approximation of the relevant widths of the layers as the follows: 1) the layer of the silane groups makes up 10?% of the total length (27 nm), 2) the layer of the first PVA shell contributes 30?% to the total length (81 nm), 3) the layer of the PVAc core contributes 30?% to the total length (81 nm), and finally 4) the layer of the second PVA shell provides 30?% of the total length (81 nm). The coverage simulation resulted in a value of 0.4, which corresponds with the assumption of low-order coverage, and is supported by the AFM scans. Correlating the results of the AFM scans, and the zeta potentials sheds some light on the formation mechanism of the silane-PVA/PVAc complex film. PMID:24039042

Repovsky, Daniel; Jane, Eduard; Palszegi, Tibor; Slobodnik, Marek; Velic, Dusan

2013-08-29

28

Effect of Hydroxyl Concentration on Chemical Sensitivity of Polyvinyl Alcohol/Carbon-Black Composite Chemiresistors  

SciTech Connect

The sensitivity and selectivity of polyvinyl alcohol (PVA) / carbon black composite films have been found to vary depending upon the hydroxylation percentage ("-OH") of the polymer. These chemiresistors made from PVA films whose polymer backbone is 88% hydroxylated (PVA88) have a high sensitivity to water, while chemiresistors made from PVA75 have a higher sensitivity to methanol. The minor differences in polymer composition result in films with different Hildebrand volubility parameters. The relative responses of several different PVA-based chemiresistors to solvents with different volubility parameters are presented. In addition, polyvinyl acetate (PVAC) films with PVA88 are used in an array to distinguish the responses to methanol-water mixtures.

Hughes, Robert C.; Patel, Sanjay V.; Yelton, W. Graham

1999-05-19

29

The shrinkage compensation of unsaturated polyester resins — polyvinyl acetate blends polymerization proceeds through fractal morphologies: characterization and simulation  

Microsoft Academic Search

Blends of unsaturated polyester, styrene and polyvinyl acetate are hot cured either between glass plates or under pressure in a molding simulator. The morphologies of the products are observed using microscopy and show their usual aspects. They are characterized according to fractal concepts by image processing; the influence of mixture composition, pressure and temperature is investigated. Based on the hypothesis

M. Ruffier; G. Merle; J. P. Pascault; H. Bouleçane; N. Vincent

1996-01-01

30

Pervaporation separation of water-acetic acid mixtures through poly(vinyl alcohol) membranes crosslinked with glutaraldehyde  

Microsoft Academic Search

Poly(vinyl alcohol) (PVA) membranes crosslinked with glutaraldehyde (GA) were prepared by a solution method for the pervaporation separation of acetic acid-water mixtures. In the solution method, dry PVA films were crosslinked by immersion for 2 days at 40°C in reaction solutions which contained different contents of GA, acetone and a catalyst, HCl. In order to fabricate the crosslinked PVA membranes

Choong-Kyun Yeom; Kew-Ho Lee

1996-01-01

31

Microwave irradiation induced modifications on the interfaces in SAN/EVA/PVC and PVAc/BPA/PVP ternary polymer blends: Positron lifetime study  

NASA Astrophysics Data System (ADS)

Ternary polymer blends of poly(styrene-co-acrylonitrile)/poly(ethylene-co-vinylacetate)/poly(vinyl chloride) (SAN/EVA/PVC) and poly(vinyl acetate)/bisphenol A/polyvinylpyrrolidone (PVAc/BPA/PVP) with different compositions have been prepared by solvent casting method and characterized by positron lifetime spectroscopy and differential scanning calorimetry DSC. Phase modifications have been induced by irradiating the blends with microwave radiation. These changes have been monitored by measuring the free-volume content in the blends. The results clearly show improved interactions between the constituent polymers of the blends upon microwave irradiation. However, the free-volume data and DSC measurements are found to be inadequate to reveal the changes at the interfaces and the interfaces determine the final properties of the blend. For this we have used hydrodynamic interaction (?ij) approach developed by us to measure strength of hydrodynamic interaction at the interfaces. These results show that microwave irradiation stabilizes the interfaces if the blend contains strong polar groups. SAN/EVA/PVC blend shows an increased effective hydrodynamic interaction from ?3.18 to ?4.85 at composition 50/35/15 upon microwave irradiation and PVAc/BPA/PVP blend shows an increased effective hydrodynamic interaction from ?3.81 to ?7.57 at composition 20/50/30 after irradiation.

Dinesh, Meghala; Chikkakuntappa, Ranganathaiah

2013-09-01

32

Space resolved relaxation dynamics of poly(vinyl acetate) close to interfaces with SiOx nanoinclusions  

NASA Astrophysics Data System (ADS)

The influence on relaxation dynamics of poly(vinyl acetate) of SiOx nanoparticles dispersed in the polymeric matrix was investigated by Local Dielectric Spectroscopy, measuring the phase loss angle in the polymer as a function of the distance from the nanoparticles. Both images of phase loss angle and acquisition of local dielectric spectra show two distinct features, namely, a faster relaxation dynamics when approaching the nanoparticle surface, and a rather large range of influence on polymer dynamics with respect to nanoparticle size, probe size, and gyration radius of the polymer.

Labardi, M.; Prevosto, D.; Nguyen, H. K.; Lucchesi, M.; Fanizza, E.; Depalo, N.; Striccoli, M.

2012-07-01

33

Evaluation of Physical and Biological Properties of Polyvinyl Alcohol\\/Chitosan Blend Films  

Microsoft Academic Search

Polyvinyl alcohol\\/chitosan (PVA\\/Cs) blend films with various compositions were prepared using glutaraldehyde (GA) as a cross-linker. The hydrophilicity and swelling behavior of the PVA\\/Cs films were assessed, and the biological properties of the PVA\\/Cs films, including cell culture in the extract, cell cytotoxicity, and hemolytic and acute systemic toxicity tests were also investigated. The results showed that all composite films

ZEQIANG HE; LIZHI XIONG

2012-01-01

34

Cellulose acetate butyrate–pH\\/thermosensitive polymer microcapsules containing aminated poly(vinyl alcohol) microspheres for oral administration of DNA  

Microsoft Academic Search

The aim of this work is to safely transport bioadhesive microspheres loaded with DNA to intestine and to test their bioadhesive properties. Poly(vinyl alcohol) (PVA) microspheres were prepared by dispersion reticulation with glutaraldehyde and further aminated. These microspheres were firstly loaded with plasmid DNA by electrostatic interactions and then entrapped in cellulose acetate butyrate (CAB) microcapsules for gastric protection. The

Gheorghe Fundueanu; Marieta Constantin; Fabrizio Bortolotti; Rita Cortesi; Paolo Ascenzi; Enea Menegatti

2007-01-01

35

Polyvinyl Alcohol Hydrogel Irradiated and Acetalized for Osteochondral Defect Repair: Mechanical, Chemical, and Histological Evaluation after Implantation in Rat Knees  

PubMed Central

Polyvinyl Alcohol (PVA) hydrogel plugs were implanted in artificial osteochondral defects on the trochlear groove of rat knees. After 0, 3, 6, 12, and 24 weeks of followup, samples containing the implants were mechanically evaluated by creep indentation test, chemically, and histologically by optical microscopy. The mechanical test pointed towards an increase of the implant creep modulus and the chemical analysis exhibited an increasing concentration of calcium and phosphorus within the implants over time. Optical microscopy showed no foreign body reaction and revealed formation, differentiation, and maintenance of new tissue at the defect/implant interface. The absence of implant wear indicated that the natural articular lubrication process was not disturbed by the implant. The performance of the irradiated and acetalized PVA was considered satisfactory for the proposed application.

Batista, N. A.; Rodrigues, A. A.; Bavaresco, V. P.; Mariolani, J. R. L.; Belangero, W. D.

2012-01-01

36

The effect of silane concentration on the adsorption of poly(vinyl acetate-co-maleate) and ? -methacryloxypropyl- trimethoxysilane onto E-glass fibers  

Microsoft Academic Search

The adsorption of a poly(vinyl acetate-co-maleate) (PVAM) emulsion onto E-glass fibers was investigated along with sizing formulations prepared by mixing the PVAM with varying concentrations of ? -methacryloxypropyltrimethoxysilane (MPS). The sized E-glass fibers were then characterized using Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and Scanning Electron Microscopy (SEM). Loss on Ignition (LOI) along with the

Christopher C. Le-Huy; Leanne G. Britcher; Janis G. Matisons

2002-01-01

37

Permeation and Separation Characteristics of Acetic Acid?Water Mixtures Through Poly(Vinyl Alcohol)\\/Malic Acid Membranes by Evapomeation and Temperature Difference Controlled Evapomeation  

Microsoft Academic Search

The characteristics of permeation and separation of acetic acid?water mixtures through 85\\/15 (v\\/v) poly(vinyl alcohol)\\/malic acid (PVA\\/MA) membranes were investigated by evapomeation (EV) and temperature difference controlled evapomeation (TDEV) methods. The effects of permeation temperature, membrane surrounding temperature, and feed composition on the permeation rate and the separation factor were studied. The permeation rates increased but separation factors decreased with

Nuran I??klan; Oya ?anl?

2005-01-01

38

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

NASA Astrophysics Data System (ADS)

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).

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

2010-06-01

39

Preparation and characterization of poly(vinyl chloride-co-vinyl acetate)-based gel electrolytes for Li-ion batteries  

SciTech Connect

Poly(vinyl chloride) (PVC)-based electrolytes, a class of the most promising polymer electrolytes, are found to suffer from solvent exudation. Two strategies were employed to suppress this shortcoming, one involving the replacement of PVC with poly(vinyl chloride-co-vinyl acetate) (PVCAC) copolymer and the other the direct utilization of solvents for PVC or PVCAC instead of using an auxiliary carrier solvent (e.g., tetrahydrofuran, THF). The thermodynamics of polymer solubility was particularly emphasized in the latter approach. N,N-dimethylformamide (DMF) and N-methyl pyrrolidionone (NMP) are preferred cosolvents of ethylene carbonate (EC) and/or propylene carbonate (PC). The PVCAC-based gel electrolytes prepared were then characterized by ionic conductivity, cyclic voltammetry, and ac impedance data. The results indicate that electrolytes containing NMP/EC mixed solvent exhibit conductivities exceeding 10{sup {minus}3} S/cm whereas the electrolytes containing DMF/EC/PC exhibit conductivities around 10{sup {minus}4} S/cm at room temperature. Moreover, the former category was found to be oxidatively stable up to 4.9 V vs. Li/Li{sup +} and the latter to 4.6 V vs. Li/Li{sup +}. Finally, ac impedance results suggest that the stability of the Li/electrolyte interface needs further improvement, which is a crucial task for most polymer gel electrolytes at present.

Sung, H.Y.; Wang, Y.Y.; Wan, C.C. [National Tsing-Hua Univ., Hsinchu (Taiwan, Province of China). Dept. of Chemical Engineering

1998-04-01

40

Comment on ``Temperature divergence of the dynamics of a poly(vinyl acetate) glass: Dielectric vs. mechanical behaviors'' [J. Chem. Phys. 136, 154901 (2012)  

NASA Astrophysics Data System (ADS)

The temperature dependence of polymer dynamics below the standard glass transition is of considerable interest. Glassy relaxation dictates the process of physical aging, and understanding these slow dynamics helps in assessing a possible divergence at a finite temperature. In a recent paper, Zhao and McKenna have measured the equilibrium dynamics of poly(vinyl acetate) in the range from Tg - 15 K to Tg + 30 K using Struiks protocol [J. Zhao and G. B. McKenna, J. Chem. Phys. 136, 154901 (2012)]. In a figure that is meant to compare their results with dielectric relaxation data from Wagner and Richert [Polymer 38, 255 (1997)], dielectric retardation data from that work is shown instead. The corrected figure shows a considerable difference in the two measurements below Tg - 10 K, Arrhenius versus Vogel-Fulcher-Tammann behavior, and a possible source of the difference is discussed.

Richert, Ranko

2013-10-01

41

Response to ``Comment on `Temperature divergence of the dynamics of a poly(vinyl acetate) glass: Dielectric vs. mechanical behaviors''' [J. Chem. Phys. 139, 137101 (2013)  

NASA Astrophysics Data System (ADS)

R. Richert has made a comment to a paper of ours in which dielectric measures on poly(vinyl acetate) suggest that there is a change in temperature dependence of the temperature shift factors from Vogel-Fulcher-Tammann (VFT) to Arrhenius near to the glass transition temperature. He notes that we made an error in the description of his data and further notes that the data we did not use show a VFT behavior to well below the glass transition. Here we respond to the comment and add additional analysis that suggest that the differences in results are related to the differences between time temperature superposition (TTS) of data and fitting the data with a Kohlrausch, Williams, and Watts function. When TTS is used on the data from Wagner and Richert [Polymer 38, 255 (1997)] the change in behavior to Arrhenius-like below Tg is recovered.

Zhao, Jing; McKenna, Gregory B.

2013-10-01

42

Low temperature cure of unsaturated polyester resins with thermoplastic additives III. Modification of polyvinyl acetate for better shrinkage control  

Microsoft Academic Search

Copolymers of vinyl acetate and acid monomers were synthesized by emulsion polymerization and applied as shrinkage control additives in the polymerization of unsaturated polyester (UP) and styrene at low temperatures. The presence of acid groups on the copolymer chain changes the selectivity of the cobalt promoter, and in turn, the relative reaction rate in the thermoplastic-rich and the UP-rich phase

W Li; L. J Lee; K. H Hsu

2000-01-01

43

Development of poly(vinyl acetate-methylacrylic acid)/chitosan/Fe3O4 nanoparticles for the diagnosis of non-alcoholic steatohepatitis with magnetic resonance imaging.  

PubMed

Non-alcoholic steatohepatitis is a burgeoning health problem. To diagnose NASH with magnetic resonance imaging (MRI), an effective contrast agent, a stable suspension of superparamagnetic Fe(3)O(4) nanoparticles, were newly developed. The negatively charged Fe(3)O(4) nanoparticles were coated with positive chitosan (CS) firstly, and then assembled with poly(vinyl acetate-methylacrylic acid) (P(VAc-MAA)). Transmission electron microscope and dynamic light scattering confirmed that the obtained P(VAc-MAA)/CS/Fe(3)O(4) nanoparticles had a spherical or ellipsoidal morphology with an average diameter in the range of 14-20 nm. The superparamagnetic property and spinel structure of the Fe(3)O(4) nanoparticles were well preserved due to the protection of the P(VAc-MAA)/CS layers on the surface of the Fe(3)O(4) nanoparticles. The in vivo rat experiments confirmed that the P(VAc-MAA)/CS/Fe(3)O(4) nanoparticles were an effective contrast agent for MRI to diagnose NASH. PMID:22976475

Luo, Xiadan; Song, Xiaoli; Zhu, Aiping; Si, Yunfeng; Ji, Lijun; Ma, Zhanrong; Jiao, Zhiyun; Wu, Jingtao

2012-09-14

44

Estimation of polyvinyl alcohol cryogel mechanical properties with four ultrasound elastography methods and comparison with gold standard testings  

Microsoft Academic Search

Tissue-mimicking phantoms are very useful in the field of tissue characterization and essential in elastography for the purpose of validating motion estimators. This study is dedicated to the characterization of polyvinyl alcohol cryogel (PVA-C) for these types of applications. A strict fabrication procedure was defined to optimize the reproducibility of phantoms having a similar elasticity. Following mechanical stretching tests, the

Jeremie Fromageau; Jean-Luc Gennisson; Cedric Schmitt; Roch L. Maurice; Rosaire Mongrain; G. Cloutier

2007-01-01

45

Modifying the MRI, elastic stiffness and electrical properties of polyvinyl alcohol cryogel using irradiation  

NASA Astrophysics Data System (ADS)

The aim of this work was to study the effect of radiation on the elastic stiffness, electrical and MRI properties of polyvinyl alcohol (PVA)-based cryogel (PVA-C). The PVA-C samples were irradiated with a 60C0 ?-source, at 2.18 × 106 Rads. The indentation measurements (an indication of elastic stiffness) reduced by about 14.6% for PVA-3C and 5.7% PVA-6C after irradiation, indicating that the material became harder/stiffer. It was found that MRI relaxation times provide an alternative and non-destructive method to evaluate the radiation effect on PVA-C. The T1 of PVA-C that had undergone three freeze thaw cycles decreased with irradiation by 10%, 25% and 35% at 1 T, 1.89 T and 3 T respectively. The T1 of PVA-C that had undergone six freeze thaw cycles decreased with irradiation by 18%, 15% and 11% at 1 T, 1.89 T and 3 T respectively. The T2 of PVA-C decreased with irradiation only at 1T, however this change is hypothesized to be due to the interaction of two spin pools in the gel. The electrical conductivity (?) and permittivity constant (?) of the unirradiated and ?-irradiated PVA-C samples were measured at different frequencies in the range 40 Hz to 1 MHz. The results demonstrated that the conductivity increased with irradiation by 50% for PVA-3C (three freeze thaw cycles) and 75% for PVA-6C (six freeze thaw cycles) at frequencies greater than 1 KHz.The permittivity decreased with irradiation up to 25% for 3C and 35% for 6C at frequencies less than 1 KHz.

Goharian, Mehran; Moran, Gerald R.; Wilson, Kyle; Seymour, Colin; Jegatheesan, Aravinthan; Hill, Michael; Thompson, R. Terry; Campbell, Gordon

2007-10-01

46

Characterization of S3Pvac Anti-Cysticercosis Vaccine Components: Implications for the Development of an Anti-Cestodiasis Vaccine  

Microsoft Academic Search

BackgroundCysticercosis and hydatidosis seriously affect human health and are responsible for considerable economic loss in animal husbandry in non-developed and developed countries. S3Pvac and EG95 are the only field trial-tested vaccine candidates against cysticercosis and hydatidosis, respectively. S3Pvac is composed of three peptides (KETc1, GK1 and KETc12), originally identified in a Taenia crassiceps cDNA library. S3Pvac synthetically and recombinantly expressed

Dunia Rassy; Raúl J. Bobes; Gabriela Rosas; Victor H. Anaya; Klaus Brehm; Beatriz Hernández; Jacquelynne Cervantes; Saúl Pedraza; Julio Morales; Nelly Villalobos; Aline S. de Aluja; Juan P. Laclette; Caris M. Nunes; Germano F. Biondi; Gladis Fragoso; Marisela Hernández; Edda Sciutto; David Joseph Diemert

2010-01-01

47

Primary Plasticizers for Poly(Vinyl Chloride).  

National Technical Information Service (NTIS)

According to the patent application, acetal derivatives of polyunsaturated fatty compositions were prepared and found to function as primary plasticizers. Poly(vinyl chloride) resins plasticized by the compositions of this application have properties equa...

R. A. Awl E. H. Pryde

1974-01-01

48

Preparation and Characterization of CoFe2O4\\/Poly Vinyl Acetate Nanocomposite  

Microsoft Academic Search

CoFe2O4 (CFO) nano-particles have been synthesized successfully by a redox chemical reaction in aqueous solution of cobalt chloride and ferric chloride. The synthesized CFO nanoparticles have been used for preparation of CFO\\/Poly vinyl acetate (CFO\\/PVAc) nanocomposite by in situ emulsion polymerization method. The nanocomposite exhibited superparamagnetic behavior at room temperature under an applied magnetic field. The synthesized CFO\\/PVAc nanocomposite has

Mohsen Mohsen-Nia; Fatemeh Seyed Mohammad Doulabi

2012-01-01

49

Ionic conductivity in polypyrrole–poly (vinyl acetate) films synthesized by chemical oxidative polymerization method  

Microsoft Academic Search

Polypyrrole (PPy) and poly (vinyl acetate) (PVAc) composite thin films were synthesized by chemical oxidative polymerization method with the solution of ferric chloride (FeCl3) oxidant in methanol. Their dc conductivities as a function of temperature (308–383K) were measured. The ionic transference numbers for the PPy–PVAc films, synthesized with different concentration of FeCl3, were determined by dc polarization technique. The transference

W. S. Barde; S. V. Pakade; S. P. Yawale

2007-01-01

50

Improved cellular response on multiwalled carbon nanotube-incorporated electrospun polyvinyl alcohol/chitosan nanofibrous scaffolds.  

PubMed

We report the fabrication of multiwalled carbon nanotube (MWCNT)-incorporated electrospun polyvinyl alcohol (PVA)/chitosan (CS) nanofibers with improved cellular response for potential tissue engineering applications. In this study, smooth and uniform PVA/CS and PVA/CS/MWCNTs nanofibers with water stability were formed by electrospinning, followed by crosslinking with glutaraldehyde vapor. The morphology, structure, and mechanical properties of the formed electrospun fibrous mats were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and mechanical testing, respectively. We showed that the incorporation of MWCNTs did not appreciably affect the morphology of the PVA/CS nanofibers; importantly the protein adsorption ability of the nanofibers was significantly improved. In vitro cell culture of mouse fibroblasts (L929) seeded onto the electrospun scaffolds showed that the incorporation of MWCNTs into the PVA/CS nanofibers significantly promoted cell proliferation. Results from this study hence suggest that MWCNT-incorporated PVA/CS nanofibrous scaffolds with small diameters (around 160 nm) and high porosity can mimic the natural extracellular matrix well, and potentially provide many possibilities for applications in the fields of tissue engineering and regenerative medicine. PMID:21353768

Liao, Huihui; Qi, Ruiling; Shen, Mingwu; Cao, Xueyan; Guo, Rui; Zhang, Yanzhong; Shi, Xiangyang

2011-02-25

51

The Effect of Agro-Wastes and Crustacean Fillers on Poly (Vinyl-Acetate) Emulsion Wood Adhesives  

Microsoft Academic Search

Cellulosic and crustacean filler materials were used to study their effects on poly(vinyl-acetate) (PVAC) emulsion wood adhesives. The elastoplastic behavior of the filler-treated PVAC emulsion was studied using differential scanning calorimetry and dynamic mechanical thermal analysis. The result revealed that the glass transition temperature (Tg) of the filler-treated polymer is not significantly changed by the addition of the filler materials,

I. U. Ogban; O. Ogbobe

2008-01-01

52

Production of ethanol from molasses at 45?°C using Kluyveromyces marxianus IMB3 immobilized in calcium alginate gels and poly(vinyl alcohol) cryogel  

Microsoft Academic Search

The thermotolerant, ethanol-producing yeast strain Kluyveromyces marxianus IMB3 has been immobilized in calcium alginate gel and poly(vinyl alcohol) cryogel (PVAC) beads. The immobilized preparations were used as biocatalyst in fed-batch reactor systems for prolonged periods. The substrate utilized in each case consisted of sugar cane molasses diluted to yield a sugar load of 140 g\\/l. During the first cycle the

S. Gough; N. Barron; A. L. Zubov; V. I. Lozinsky; A. P. McHale

1998-01-01

53

Effective protection induced by three different versions of the porcine S3Pvac anticysticercosis vaccine against rabbit experimental Taenia pisiformis cysticercosis.  

PubMed

In an effort to develop an effective and affordable oral vaccine against porcine Taenia solium cysticercosis, the S3Pvac anti-cysticercosis vaccine was expressed in papaya calli. Taenia pisiformis experimental rabbit cysticercosis was used as a model to compare the efficacy of the oral vaccine vs. the injectable S3Pvac-synthetic and S3Pvac-phage versions. Oral S3Pvac-papaya significantly reduced the expected number of hepatic lesions and peritoneal cysticerci to a similar extent than the injectable vaccines. This study reports for the first time an effective oral vaccine against T. pisiformis cysticercosis, possibly useful against porcine T. solium cysticercosis. PMID:22349522

Betancourt, Miguel Angel; de Aluja, Aline S; Sciutto, Edda; Hernández, Marisela; Bobes, Raúl J; Rosas, Gabriela; Hernández, Beatriz; Fragoso, Gladis; Hallal-Calleros, Claudia; Aguilar, Liliana; Flores-Peréz, Iván

2012-02-18

54

Development of the S3Pvac vaccine against porcine Taenia solium cysticercosis: a historical review.  

PubMed

Herein we present a review of our research dealing with vaccination against experimental and naturally acquired porcine Taenia solium cysticercosis using Taenia crassiceps-derived antigens. Results strongly support that the different versions of S3Pvac vaccine are indeed effective against porcine T. solium cysticercosis. Immunological results related to vaccination prove that protection is at least partially mediated by specific immunity. The data also support the validity of T. crassiceps murine cysticercosis as an effective tool to identify vaccine candidates against some metacestode infections. PMID:23445359

Sciutto, Edda; Fragoso, Gladis; Hernández, Marisela; Rosas, Gabriela; Martínez, José J; Fleury, Agnès; Cervantes, Jacquelynne; Aluja, Aline; Larralde, Carlos

2013-02-27

55

In situ Self Cross-Linking of Polyvinyl Alcohol Battery Separators.  

National Technical Information Service (NTIS)

The method disclosed is used to produce a polyvinyl alcohol sheet material wherein the polyvinyl alcohol is substantially free of 1,2 diol units, and has an acetal self cross-linked structure wherein the acetal content is determined by the 1,2 diol conten...

W. H. Philipp L. C. Hsu D. W. Sheibley

1978-01-01

56

Development of the S3Pvac vaccine against murine Taenia crassiceps cysticercosis: a historical review.  

PubMed

Our work of the last 25 yr was concerned with the development of a vaccine aimed to prevent porcine Taenia solium cysticercosis and was based on cross-reacting Taenia crassiceps antigens that had proved protective against experimental intraperitoneal murine T. crassiceps cysticercosis (EIMTcC). In recent times the efficacy of the vaccine has been considered in need of confirmation, and the use of EIMTcC has been questioned as a valid tool in screening for vaccine candidates among the many antigens possibly involved. A review of our work divided in 2 parts is presented at this point, the first dealing with EIMTcC and the second with porcine T. solium cysticercosis (presented in this issue). Herein, we revise our results using EIMTcC as a measure of the protective capacity of T. crassiceps complex antigen mixtures, of purified native antigens, and of S3Pvac anti-cysticercosis vaccine composed by 3 protective peptides: GK-1, KETc1, and KETc12 either synthetic or recombinantly expressed and collectively or separately, by diverse delivery systems when administered at different doses and by different routes. Statistical analyses of the data lead confidently to the strong inference that S3Pvac is indeed an effective vaccine against EIMTcC via specific and non-specific mechanisms of protection. PMID:23409920

Sciutto, Edda; Fragoso, Gladis; Hernández, Marisela; Rosas, Gabriela; Martínez, José J; Fleury, Agnès; Cervantes, Jacquelynne; Aluja, Aline; Larralde, Carlos

2013-02-14

57

Poly(N-vinylpyrrolidone)-block-poly(vinyl acetate) as a drug delivery vehicle for hydrophobic drugs.  

PubMed

Poly((N-vinylpyrrolidone)-block-poly(vinyl acetate)) (PVP-b-PVAc) block copolymers of varying molecular weight and hydrophobic block lengths were synthesized via controlled radical polymerization and investigated as carriers for the solubilization of highly hydrophobic riminophenazine compounds. These compounds have recently been shown to exhibit a strong activity against a variety of cancer types. PVP-b-PVAc self-assembles into polymer vesicles in aqueous media, and the dialysis method was used to load the water-insoluble drug (clofazimine) into these polymer vesicles. The polymer vesicles were characterized by 1H NMR spectroscopy to confirm vesicle formation and the incorporation of the anticancer drugs into the polymer vesicles. Dynamic light scattering was used to determine the particle size and particle size distribution of the drug-loaded vesicles as well as the stability of the vesicles under physiological conditions. The size of the polymer vesicles did not increase upon loading with clofazimine, and the particle size of 180-200 nm and the narrow particle size distribution were maintained. The morphology of the vesicles was examined by transmission electron microscopy. The polymer vesicles had a relatively high drug loading capacity of 20 wt %. In vitro cytotoxicity studies of PVP-b-PVAc and drug-loaded PVP-b-PVAc were performed against MDA-MB-231 multidrug-resistant breast epithelial cancer cells and MCF12A nontumorigenic breast epithelial cells. In vitro experiments demonstrated that the PVP-b-PVAc drug carrier showed no cytotoxicity, which confirms the biocompatibility of the PVP-b-PVAc drug carrier. The results indicate that the present PVP-b-PVAc block copolymer could be a potential candidate as a drug carrier for hydrophobic drugs. PMID:23116120

Bailly, Nathalie; Thomas, Mark; Klumperman, Bert

2012-11-14

58

Stereoregular Polyvinyl Nitrate.  

National Technical Information Service (NTIS)

Isotactic polyvinyl nitrate (PVN) was prepared to investigate the effect of stereorgularity on the physical properties of PVN. The isotatic PVN had a higher softening point and was more difficult to stabilize than regular PVN. (Author)

R. A. Strecker

1980-01-01

59

Thermal degradation of poly(vinyl butyral) laminated safety glass  

Microsoft Academic Search

The effect of thermal treatment on the chemical structure of plasticized poly(vinyl butyral) (PVB) laminated safety glass was investigated in the temperature range 50–200 °C using infra-red spectroscopy and viscosity measurements. The infra-red spectra showed a large reduction in both the residual hydroxyl and acetate groups present in PVB, together with the complete disappearance of the cyclic acetal group. Moreover,

Nabil M. Safy El-Din; Magdy W. Sabaa

1995-01-01

60

Design and manufacture of a polyvinyl alcohol (PVA) cryogel tri-leaflet heart valve prosthesis.  

PubMed

Although current artificial heart valves are life sustaining medical devices, improvements are still necessary to address deficiencies. Bioprosthetic valves have a compromised fatigue life, while mechanical valves have better durability but are prone to thromboembolic complications. A novel, one-piece, tricuspid valve, consisting of leaflets, stent and sewing ring, made entirely from the hydrogel, polyvinyl alcohol cryogel (PVA-C), has been developed and demonstrated. This valve has three thin leaflets attached to a cylindrical stent. In order to approximate the complex shape of the surface of the natural heart valve leaflets, two different geometries have been proposed: revolution about an axis of a hyperboloid shape and revolution about an axis of an arc subtending (joining) two straight lines. The parameters of both geometries were examined based on a compromise between avoiding sharp curvature of leaflets and minimization of the central opening of the valve when closed. The revolution of an arc subtending two straight lines was selected as the preferred geometry since it has the benefit of a smaller central opening when the value of the maximum curvature for the leaflets is the same for each valve geometry. A cavity mold has been designed and constructed to form the PVA-C heart valve. The three leaflets were formed and integrated into the stent and sewing ring in a single process. Prototype heart valves were manufactured in the mold from a solution of PVA and water, by controlled freezing and thawing cycles. PMID:15121052

Jiang, Hongjun; Campbell, Gord; Boughner, Derek; Wan, Wan-Kei; Quantz, Mackenzie

2004-05-01

61

SOURCE ASSESSMENT: POLYVINYL CHLORIDE  

EPA Science Inventory

This report summarizes data on air emissions from the polyvinyl chloride (PVC) industry. PVC is manufactured by 20 companies at 35 plants. Each plant uses one or more of four possible polymerization processes: (1) suspension polymerization, (2) emulsion polymerization, (3) bulk p...

62

Recombinant S3Pvac-phage anticysticercosis vaccine: Simultaneous protection against cysticercosis and hydatid disease in rural pigs.  

PubMed

This paper provides macroscopic and histological evidence on the statistically significant protective effects of S3Pvac-phage vaccination against porcine cysticercosis and hydatidosis. The study included 391 rustically bred pigs (187 vaccinated and 204 controls). Vaccination significantly reduced the prevalence of cysticercosis by 61.7%. Vaccination also significantly reduced by 56.1% the prevalence of hydatidosis caused by Echinococcus granulosus in pigs. The presence of the vaccine epitopes in both cestodes is probably involved in the cross-protection observed. Increased inflammation was found in 5% of cysticerci recovered from controls, versus 24% from vaccinated pigs (P<0.01). Hydatid cysts were non-inflammatory in either group. Vaccination was effective to prevent one single disease, but it failed to prevent the simultaneous infections with both parasites in a same pig. The widening of the S3Pvac-phage vaccine protective repertoire to include hydatidosis is a convenient feature that should reduce the prevalence of two frequent zoonoses that affect rustic porcine breading with a single action. Thus, the costs of two different vaccination programs would be reduced to a single one with significant reduction in both zoonoses. PMID:21251758

Morales, Julio; de Aluja, Aline S; Martínez, Jose Juan; Hernández, Marisela; Rosas, Gabriela; Villalobos, Nelly; Hernández, Beatriz; Blancas, Abel; Manoutcharian, Karen; Gevorkian, Goar; Cervantes, Jacquelynne; Díaz, Alicia; Fleury, Agnes; Fragoso, Gladis; Larralde, Carlos; Sciutto, Edda

2010-10-27

63

Ceramic-supported polymer membranes for pervaporation of binary organic\\/organic mixtures  

Microsoft Academic Search

Asymmetric tubular alumina-supported poly(vinyl acetate) (PVAc) and poly(vinyl pyrrolidone) (PVP) membranes were created and characterized by pervaporation separation of binary mixtures of methanol and methyl tert-butyl ether (MTBE). The active separation layer was created by free-radical graft polymerization of PVAc and PVP onto a vinylsilane-modified alumina substrate with an average native pore diameter of 50Å. The separation layer consisted of

Wayne Yoshida; Yoram Cohen

2003-01-01

64

Improvement of the synthetic tri-peptide vaccine (S3Pvac) against porcine Taenia solium cysticercosis in search of a more effective, inexpensive and manageable vaccine  

Microsoft Academic Search

Vaccination of pigs may curtail Taenia solium transmission by reducing the number of cysticerci, the precursors of adult intestinal tapeworms in humans. Several antigen preparations induce protection against porcine cysticercosis in experimental settings but only one subunit vaccine (S3Pvac) has been tested and proved effective in the field against naturally acquired disease. Besides improving of the vaccine's effectiveness, significant reductions

Edda Sciutto; Gabriela Rosas; Marisela Hernández; Julio Morales; Carmen Cruz-Revilla; Andrea Toledo; Karen Manoutcharian; Goar Gevorkian; Abel Blancas; Gonzalo Acero; Beatriz Hernández; Jacquelynne Cervantes; Raul J. Bobes; Fernando A. Goldbaum; Mirna Huerta; Alicia Diaz-Orea; Agnes Fleury; Aline S. de Aluja; Jose Luis Cabrera-Ponce; Luis Herrera-Estrella; Gladis Fragoso; Carlos Larralde

2007-01-01

65

75 FR 61175 - Polyvinyl Alcohol From Taiwan  

Federal Register 2010, 2011, 2012, 2013

...731-TA-1088 (Final)] Polyvinyl Alcohol From Taiwan AGENCY: United...less-than-fair-value imports from Taiwan of polyvinyl alcohol, provided for in subheading...of Commerce that imports of polyvinyl alcohol from Taiwan are being sold...

2010-10-04

66

76 FR 13660 - Polyvinyl Alcohol From Taiwan  

Federal Register 2010, 2011, 2012, 2013

...731-TA-1088 (Final)] Polyvinyl Alcohol From Taiwan Determination On...reason of imports from Taiwan of polyvinyl alcohol, provided for under subheading...by Commerce that imports of polyvinyl alcohol from Taiwan were being...

2011-03-14

67

Heat resistance poly(vinyl alcohol) hydrogel  

NASA Astrophysics Data System (ADS)

Six methods were used to evaluate the heat resistance of poly(vinyl alchol) (PVA) hydrogel prepared by a combination of electron beam irradiation and acetalization of PVA. The physical properties of the hydrogel depended on the degree of acetalization which was affected by content of water in PVA sheet of acetalization in formaldehyde solution at 60°C. It was found that the optimum water content was 20-30%. The acetalized PVA sheet gave maximum tensile strength in electron beams irradiatio nat 100 kGy. The tensile strength of the hydrogel film increased to 20 MPa from 14 MPa by the irradiation. Heat resistance of the hydrogel was evaluated by measuring the mechanical properties after sterilization in a steam autoclave at 121°C for 90 min. The tensile strength decreased to 10 MPa whereas the elongation at break increased to 300%. The tackiness of the hydrogel was improved by radiation grafting of acrylic acid. Wholesomeness of the hydrogel as a wound dressing was evaluated by attaching to a burn or wound of the back skin of marmots. Advantages of the hydrogel over a gauze dressing were homogeneous adhesion to the affected parts, easy removal without damage to renewed skin and slightly faster rate of reconstruction of the injured skin.

Yoshii, F.; Makuuchi, K.; Darwis, D.; Iriawan, T.; Razzak, M. T.; Rosiak, Janusz M.

1995-08-01

68

Comparative evaluation of tensile bond strength of a polyvinyl acetate-based resilient liner following various denture base surface pre-treatment methods and immersion in artificial salivary medium: An in vitro study  

PubMed Central

Background and Aim: This study was formulated to evaluate and estimate the influence of various denture base resin surface pre-treatments (chemical and mechanical and combinations) upon tensile bond strength between a poly vinyl acetate-based denture liner and a denture base resin. Materials and Methods: A universal testing machine was used for determining the bond strength of the liner to surface pre-treated acrylic resin blocks. The data was analyzed by one-way analysis of variance and the t-test (? =.05). Results: This study infers that denture base surface pre-treatment can improve the adhesive tensile bond strength between the liner and denture base specimens. The results of this study infer that chemical, mechanical, and mechano-chemical pre-treatments will have different effects on the bond strength of the acrylic soft resilient liner to the denture base. Conclusion: Among the various methods of pre-treatment of denture base resins, it was inferred that the mechano-chemical pre-treatment method with air-borne particle abrasion followed by monomer application exhibited superior bond strength than other methods with the resilient liner. Hence, this method could be effectively used to improve bond strength between liner and denture base and thus could minimize delamination of liner from the denture base during function.

Philip, Jacob M.; Ganapathy, Dhanraj M.; Ariga, Padma

2012-01-01

69

SYNTHESIS AND CHARACTERISTICS OF Ag POLYMER NANOCOMPOSITES  

Microsoft Academic Search

In this study, a metal chelate polymer (MCP) chemical approach has been adopted to fabricate metal-containing polymer used in metal-polymer nanocomposite. The silver-containing polymer was prepared by adding silver nitrate (AgNO3) to a solution of polyvinyl acetate (PVAc) dissolved in formic acid (HCOOH) to form the PVAc-AgNO3 MCP solution, and the resultant was cast to form the MCP film. The

C. J. Huang; W. P. Hsieh; H. C. Yao; M. C. Chiu; F. S. Shieu

70

Identification of additives in poly(vinylacetate) artist’s paints using PY-GC-MS  

Microsoft Academic Search

Commercial poly(vinyl acetate) (PVAc) paint formulations for artists include a number of compounds in addition to the PVAc\\u000a polymer and pigments to improve the physical and chemical properties of the resulting product. Among the most common additives\\u000a are surfactants, coalescing agents, defoamers, freeze–thaw agents and thickeners. These products significantly influence the\\u000a behaviour of the dried film. Nevertheless, they are usually

Miguel F. Silva; Maria Teresa Doménech-Carbó; Laura Fuster-López; Marion F. Mecklenburg; Susana Martin-Rey

2010-01-01

71

40 CFR 414.40 - Applicability; description of the thermoplastic resins subcategory.  

Code of Federal Regulations, 2010 CFR

...Polyvinyl Acetate *Polyvinyl AcetateâPVC Copolymers *Polyvinyl Acetate Copolymers *Polyvinyl Acetate Resins Polyvinyl Alcohol Resin Polyvinyl Chloride Polyvinyl Chloride, Chlorinated *Polyvinyl Ether-Maleic Anhydride...

2010-07-01

72

40 CFR 414.40 - Applicability; description of the thermoplastic resins subcategory.  

Code of Federal Regulations, 2010 CFR

...Polyvinyl Acetate *Polyvinyl AcetateâPVC Copolymers *Polyvinyl Acetate Copolymers *Polyvinyl Acetate Resins Polyvinyl Alcohol Resin Polyvinyl Chloride Polyvinyl Chloride, Chlorinated *Polyvinyl Ether-Maleic Anhydride...

2009-07-01

73

Estimation of polyvinyl alcohol cryogel mechanical properties with four ultrasound elastography methods and comparison with gold standard testings.  

PubMed

Tissue-mimicking phantoms are very useful in the field of tissue characterization and essential in elastography for the purpose of validating motion estimators. This study is dedicated to the characterization of polyvinyl alcohol cryogel (PVA-C) for these types of applications. A strict fabrication procedure was defined to optimize the reproducibility of phantoms having a similar elasticity. Following mechanical stretching tests, the phantoms were used to compare the accuracy of four different elastography methods. The four methods were based on a one-dimensional (1-D) scaling factor estimation, on two different implementations of a 2-D Lagrangian speckle model estimator (quasistatic elastography methods), and on a 1-D shear wave transient elastography technique (dynamic method). Young's modulus was investigated as a function of the number of freeze-thaw cycles of PVA-C, and of the concentration of acoustic scatterers. Other mechanical and acoustic parameters-such as the speed of sound, shear wave velocity, mass density, and Poisson's ratio-also were assessed. The Poisson's ratio was estimated with good precision at 0.499 for all samples, and the Young's moduli varied in a range of 20 kPa for one freeze-thaw cycle to 600 kPa for 10 cycles. Nevertheless, above six freeze-thaw cycles, the results were less reliable because of sample geometry artifacts. However, for the samples that underwent less than seven freeze-thaw cycles, the Young's moduli estimated with the four elastography methods showed good matching with the mechanical tensile tests with a regression coefficient varying from 0.97 to 1.07, and correlations R2 varying from 0.93 to 0.99, depending on the method. PMID:17375819

Fromageau, Jérémie; Gennisson, Jean-Luc; Schmitt, Cédric; Maurice, Roch L; Mongrain, Rosaire; Cloutier, Guy

2007-03-01

74

Dispersion stability of indium tin oxide nanoparticles in butyl acetate  

Microsoft Academic Search

A colloidal dispersion of indium tin oxide (ITO) nanoparticles in butyl acetate solvent was achieved using a milling process in which PVP or PEG were used as a dispersant. The influences of Polyvinyl pyrrolidone (PVP) and Polyethylene glycol (PEG) dispersants on the stability of ITO suspension were studied by Zeta potential value, Nano-particle size measurement and sedimentation experiment. The results

Qiming Xu; Zhang Lei; Yanyan Yao

2011-01-01

75

Polyvinyl Esters of Omega-H-Perfluoroacids and Polyvinyl Alcohol Obtained from Them,  

National Technical Information Service (NTIS)

By means of radical polymerization at 20 we obtained polyvinyl esters of omega-H-perfluoroacids from monomers. The product of their saponification - polyvinyl alcohol (PVA) - differs significantly from PVA which is obtained by other methods (mainly with r...

Y. N. Rostovskiy L. D. Budovskaya

1987-01-01

76

75 FR 15726 - Polyvinyl Alcohol From Taiwan; Determination  

Federal Register 2010, 2011, 2012, 2013

...Preliminary) (Remand)] Polyvinyl Alcohol From Taiwan; Determination...reason of imports from Taiwan of polyvinyl alcohol provided for in subheading 3905...of allegedly LTFV imports of polyvinyl alcohol from...

2010-03-30

77

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

Federal Register 2010, 2011, 2012, 2013

...A-583-841] Antidumping Duty Order: Polyvinyl Alcohol From Taiwan AGENCY: Import...an antidumping duty order on polyvinyl alcohol (PVA) from Taiwan. DATES...investigation of PVA from Taiwan. See Polyvinyl Alcohol From Taiwan: Final...

2011-03-15

78

21 CFR 177.1670 - Polyvinyl alcohol film.  

Code of Federal Regulations, 2013 CFR

... 2013-04-01 2013-04-01 false Polyvinyl alcohol film. 177.1670 Section 177.1670...Use Food Contact Surfaces § 177.1670 Polyvinyl alcohol film. Polyvinyl alcohol film may be safely used in contact...

2013-04-01

79

21 CFR 177.1670 - Polyvinyl alcohol film.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 2009-04-01 true Polyvinyl alcohol film. 177.1670 Section 177.1670...Use Food Contact Surfaces § 177.1670 Polyvinyl alcohol film. Polyvinyl alcohol film may be safely used in contact...

2010-01-01

80

21 CFR 177.1670 - Polyvinyl alcohol film.  

Code of Federal Regulations, 2010 CFR

... 2009-04-01 2009-04-01 false Polyvinyl alcohol film. 177.1670 Section 177.1670...Use Food Contact Surfaces § 177.1670 Polyvinyl alcohol film. Polyvinyl alcohol film may be safely used in contact...

2009-04-01

81

Polyvinyl alcohol hydrogels for iontohporesis  

NASA Astrophysics Data System (ADS)

Transdermal therapeutic systems propound controlled release of active ingredients through the skin into the systemic circulation in a predictive manner. Drugs administered through these systems escape first-pass metabolism and maintain a steady state scenario similar to a continuous intravenous infusion for up to several days. The iontophoresis deal with the systemic delivery of the bioactive agents (drug) by applying an electric current. It is basically an injection without the needle. The iontophoretic system requires a gel-based matrix to accommodate the bioactive agent. Hydrogels have been used by many investigators in controlled-release drug delivery systems because of their good tissue compatibility and easy manipulation of swelling level and, thereby, solute permeability. In this work we have prepared polyvinyl alcohol (PVA) hydrogel. We have cross linked polyvinyl alcohol chemically with Glutaraldehyde with different wt%. FTIR study reveals the chemical changes during cross linking. Swelling in water, is done to have an idea about drug loading and drug release from the membrane. After drug loading to the hydrogels, we have studied the drug release property of the hydrogels using salicylic acid as a model drug.

Bera, Prasanta; Alam, Asif Ali; Arora, Neha; Tibarewala, Dewaki Nandan; Basak, Piyali

2013-06-01

82

Biocorrosion behavior and cell viability of adhesive polymer coated magnesium based alloys for medical implants  

NASA Astrophysics Data System (ADS)

The present study was ultimately aimed to design novel adhesive biodegradable polymer, poly(vinyl acetate) (PVAc), coatings onto Mg based alloys by the dip-coating technique in order to control the degradation rate and enhance the biocompatibility of magnesium alloys. The influence of various solvents on PVAc surface topography and their protection of Mg alloys were dramatically studied in vitro. Electrochemical polarization, degradation, and PVAc film cytocompatibility were also tested. Our results showed that the solvent had a significant effect on coating quality. PVAc/dichloromethane solution showed a porous structure and solution concentration could control the porous size. The coatings prepared using tetrahydrofuran and dimethylformamide solvents are exceptional in their ability to generate porous morphology even at low polymer concentration. In general, the corrosion performance appears to be different on different PVAc-solvent system. Immersion tests illustrated that the porous morphology on PVAc stabilized corrosion rates. A uniform corrosion attack in artificial simulation body fluid was also exhibited. The cytocompatibility of osteoblast cells (MC3T3) revealed high adherence, proliferation, and survival on the porous structure of PVAc coated Mg alloy, which was not observed for the uncoated samples. This novel PVAc coating is a promising candidate for biodegradable implant materials, which might widen the use of Mg based implants.

Abdal-hay, Abdalla; Dewidar, Montasser; Lim, Jae Kyoo

2012-11-01

83

Determination of the electrical behaviour of surfactant treated polymer\\/carbon black composite gas sensors  

Microsoft Academic Search

The effect of surfactants on the properties of poly(vinyl acetate) (PVAc)\\/carbon black (CB) composite gas sensors was examined. Percolation curves of the composites with and without surfactant were prepared. The percolation curves of surfactant treated composites showed that the resistivity of the composite was increased due to better dispersion of the CB and also the prevention of the CB from

K. Arshak; E. Moore; L. Cavanagh; J. Harris; B. McConigly; C. Cunniffe; G. Lyons; S. Clifford

2005-01-01

84

Termite Resistance of Polyvinyl Chloride Plastics.  

National Technical Information Service (NTIS)

A project for determining the nature of termite attack upon polymeric materials is in progress. Thirty-two formulations containing polyvinyl chloride resin were prepared incorporating, variously, four plasticizers, three insecticides and two degrees of ha...

J. D. Bultman J. M. Leonard C. R. Southwell

1966-01-01

85

Electrophoresis in Polyvinyl-Alcohol Gel.  

National Technical Information Service (NTIS)

It was found that electrophoresis in polyvinyl-alcohol, although not completely equivalent to that in polyacrylamide, is entirely possible and can accordingly be employed as an alternative method in certain cases, e.g. difficulties of procurement of polya...

C. Reich H. Sieber

1967-01-01

86

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

Microsoft Academic Search

Polyvinyl alcohol and polyvinyl pyrrolidone (PVA–PVP) blended hydrogel for wound dressing has been prepared by using gamma rays irradiation technique. The gel fraction, mechanical properties, the water content and water absorption performance of the hydrogels were measured. It was found that the gel fraction increases with increasing irradiation dose but never reaches 100% of gel. The PVA\\/PVP blended hydrogel has

Mirzan T Razzak; Darmawan Darwis; Zainuddin; Sukirno

2001-01-01

87

The effect of polyvinyl alcohol and polyvinyl pyrrolidone on diffusion artifacts in lactate dehydrogenase histochemistry  

Microsoft Academic Search

The effect of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP), alone and in combination, on diffusion artifacts in histochemical incubations has been investigated using LDH as model enzyme. By measuring the amount of formazan in the medium at the end of the incubation it has been shown that both substances, but especially PVA, are effective in limiting diffusion. The significance

Hans A. Dahl; Svein Ivar Mellgren

1970-01-01

88

Modified alginate composite membranes for the dehydration of acetic acid  

Microsoft Academic Search

Alginate composite membranes cross-linked with 1,6-hexanediamine (HDM) or poly(vinyl alcohol) (PVA) were prepared by casting an aqueous solution of alginate and HDM or PVA on a hydrolyzed microporous polyacrylonitrile (PAN) membrane and characterized by pervaporation separation of acetic acid\\/water mixtures. The influence of hydrolysis of PAN support layer and HDM content in dense layer on separation performance of the composite

Xin-Ping Wang

2000-01-01

89

A review of polyvinyl alcohol and its uses in cartilage and orthopedic applications.  

PubMed

Polyvinyl alcohol (PVA) is a synthetic polymer derived from polyvinyl acetate through partial or full hydroxylation. PVA is commonly used in medical devices due to its low protein adsorption characteristics, biocompatibility, high water solubility, and chemical resistance. Some of the most common medical uses of PVA are in soft contact lenses, eye drops, embolization particles, tissue adhesion barriers, and as artificial cartilage and meniscus. The purpose of this review is to evaluate the available published information on PVA with respect to its safety as a medical device implant material for cartilage replacement. The review includes historical clinical use of PVA in orthopedics, and in vitro and in vivo biocompatibility studies. Finally, the safety recommendation involving the further development of PVA cryogels for cartilage replacement is addressed. PMID:22514196

Baker, Maribel I; Walsh, Steven P; Schwartz, Zvi; Boyan, Barbara D

2012-04-19

90

Polyvinyl Alcohol Cross-Linked with 2 Aldehydes.  

National Technical Information Service (NTIS)

A film-forming polyvinyl alcohol resin is admixed, in aqueous solution, with a dialdehyde crosslinking agent which is capable of crosslinking the polyvinyl alcohol resin and a water soluble acid aldehyde containing a reactive aldehyde group capable of rea...

D. W. Sheibley L. L. Rieker L. C. Hsu M. A. Manzo

1982-01-01

91

Polymerization of vinyl acetate in bulk and emulsion by gamma irradiation  

NASA Astrophysics Data System (ADS)

The vinyl acetate polymerization to produce poly(vinyl acetate) was carried out in bulk and emulsion using a 60Co gamma irradiator Gammacell-220 type. The irradiation was carried out in a dose rate of 5.25 and 5.30kGy/h, respectively. The polymers obtained were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC) and gel permeation chromatography (GPC). Tests of density, hardness and Vicat softening temperature were carried out.

Mesquita, Andrea C.; Mori, Manoel N.; Andrade E Silva, Leonardo G.

2004-09-01

92

Radiolysis of tetrazolium salts in polyvinyl alcohol  

SciTech Connect

The radiation chemical yields of formazans were measured in binary systems containing polyvinyl alcohol and tetrazolium salts as additives; it was established that they are more than half of the yields of radicals in pure polyvinyl alcohol. The ESR spectra of the indicated systems were measured at various temperatures, and the relative changes in the radical concentrations were determined. It was suggested that the increase in the concentration of single radicals at T > 400 K is due to the participation of radical pairs in the reaction. 15 refs., 4 figs., 1 tab.

Kriminskaya, Z.K.; Ginzburg, S.F.; Molin, A.A.

1992-01-01

93

Polyvinyl alcohol battery separator containing inert filler  

SciTech Connect

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

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

1981-06-01

94

Cross-Linked Polyvinyl Alcohol and Method of Making Same.  

National Technical Information Service (NTIS)

A method is described for producing cross-linked polyvinyl alcohol battery separators. A film-forming polyvinyl alcohol resin is admixed, in aqueous solution, with a dialdehyde cross-linking agent which is capable of cross-linking the polyvinyl alcohol re...

D. W. Sheibley L. L. Rieker L. C. Hsu M. A. Manzo

1981-01-01

95

The Biological Evaluation of Poly (Vinyl Acetate-Co-Crotonic Acid) Ionomer Hydrogel Coatings.  

National Technical Information Service (NTIS)

Poly(vinyl acetate-co-2%-crotonic acid) 60% sodium ionomer hydrogel was found to be the most thromboresistant hydrogel evaluated in our screening studies. The ionomer hydrogel was graft-coated onto substrate surfaces from an ethanol solution of its monome...

W. F. Beach D. D. Stewart

1980-01-01

96

Laser Ablative Deposition of Polymer Films: A Promise for Sensor Fabrication  

NASA Astrophysics Data System (ADS)

There is a continuing interest in the use of polymer films as insulating components of sensors; a number of such films have been prepared by polymer sputtering or vacuum deposition processes involving gas phase pyrolysis/photolysis and by plasma decomposition of monomers. An attractive and rather new technique for the deposition of novel polymer films is IR laser ablation of polymers containing polar groups. We have recently studied this process with poly(vinyl chloride) (PVC), poly(vinyl acetate) (PVAc) and poly(vinyl chloride-co-vinyl acetate) P(VC/VAc) to establish its specific features and differences to conventional pyrolysis.

Blazevska-Gilev, Jadranka; Kup?ík, Jaroslav; Šubrt, Jan; Pola, Josef

97

Polyvinyl Alcohol Particle Size and Suspension Characteristics  

Microsoft Academic Search

PURPOSE: To evaluate the size and shape of commercially available polyvinyl alcohol (PVA) particles and to determine whether they change in size when suspended in nonionic contrast and in a solution of nonionic contrast and absolute alcohol. METHODS: The two-dimensional area and the long and short axis of PVA particles from several different vendors were measured using a light microscope

Colin P. Derdeyn; Christopher J. Moran; DeWitte T. Cross; Hans H. Dietrich; Ralph G. Dacey

98

POLY(VINYL ACETATE) AND POLY(VINYL ACETATE-CO-ETHYLENE) LATEXES VIA DISPERSION POLYMERIZATIONS IN CARBON DIOXIDE. (R826115)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

99

Effect of Heat Treatment on Some Mechanical Properties of Laminated Window Profiles Manufactured Using Two Types of Adhesives  

PubMed Central

The mechanical properties of laminated window profiles manufactured using two types of adhesives were determined. The objective of this study is to evaluate the effects of heat treatment on some mechanical properties of laminated window profiles that manufactured from Kosipo (Entandrophragma candollei Harms.) using differenet type adhesives. Commercially produced polyurethane based Macroplast UR 7221 and polyvinyl acetate (PVAc) adhesive were used for experiments. The overall test results were found to be comparable to those obtained in the previous studies. Both types of adhesives resulted in significant differences in their strength characteristics at 95% confidence level. Adhesive UR 7221 improved the overall properties of the samples in contrast to PVAc.

Korkut, Derya Sevim; Korkutand, Suleyman; Dilik, Tuncer

2008-01-01

100

RED Facts: Tridecenyl Acetates.  

National Technical Information Service (NTIS)

This fact sheet summarizes the information in the RED document for reregistration case 4116, tridecenyl acetates. Tridecenyl acetates are sex attractant pheromones used in tomato fields to disrupt the mating behavior of tomato pinworms.

1996-01-01

101

Coordination of Lanthanide Acetates  

SciTech Connect

A study of the structures of hydrated and anhydrous lanthanide acetates by X-ray diffraction, infrared spectra, and absorption spectra demonstrates that there are three separate structures for hydrated lanthanide acetates and four structures for anhydrous acetates. This paper discusses the results of that study.

Karraker, D.G.

2001-08-29

102

40 CFR 61.64 - Emission standard for polyvinyl chloride plants.  

Code of Federal Regulations, 2013 CFR

...for polyvinyl chloride dispersion resins, excluding latex...stripper(s)] for dispersion polyvinyl chloride resins...determined on a dry solids basis; (ii) 0...chloride product for dispersion polyvinyl chloride resins...determined on a dry solids basis. (ii)...

2013-07-01

103

76 FR 5562 - Polyvinyl Alcohol From Taiwan: Final Determination of Sales at Less Than Fair Value  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-583-841] Polyvinyl Alcohol From Taiwan: Final Determination...has determined that imports of polyvinyl alcohol (PVA) from Taiwan are being...antidumping duty investigation of polyvinyl alcohol from Taiwan. See...

2011-02-01

104

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

Federal Register 2010, 2011, 2012, 2013

...Administration [A-583-841] Polyvinyl Alcohol From Taiwan: Rescission of...the antidumping duty order on polyvinyl alcohol (PVA) from Taiwan for the...CCPC to the Department, ``Polyvinyl Alcohol from Taiwan: Withdrawal...

2013-07-01

105

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

Federal Register 2010, 2011, 2012, 2013

...Antidumping Duty Investigation: Polyvinyl Alcohol From Taiwan AGENCY: Import...antidumping duty investigation on polyvinyl alcohol from Taiwan. See Initiation...Anti-Dumping Duty Investigation: Polyvinyl Alcohol From Taiwan, 69 FR...

2010-07-01

106

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

Federal Register 2010, 2011, 2012, 2013

...Administration [A-583-841] Polyvinyl Alcohol From Taiwan: Preliminary Results...the antidumping duty order on polyvinyl alcohol (PVA) from Taiwan. The period...Duty Administrative Review: Polyvinyl Alcohol from Taiwan;...

2013-04-08

107

Pallidol hexa-acetate ethyl acetate monosolvate  

PubMed Central

The entire mol­ecule of pallidol hexa­acetate {systematic name: (±)-(4bR,5R,9bR,10R)-5,10-bis­[4-(acet­yloxy)phen­yl]-4b,5,9b,10-tetra­hydro­indeno­[2,1-a]indene-1,3,6,8-tetrayl tetra­acetate} is completed by the application of twofold rotational symmetry in the title ethyl acetate solvate, C40H34O12·C4H8O2. The ethyl acetate mol­ecule was highly disordered and was treated with the SQUEEZE routine [Spek (2009 ?). Acta Cryst. D65, 148–155]; the crystallographic data take into account the presence of the solvent. In pallidol hexa­acetate, the dihedral angle between the fused five-membered rings (r.m.s. deviation = 0.100?Å) is 54.73?(6)°, indicating a significant fold in the mol­ecule. Significant twists between residues are also evident as seen in the dihedral angle of 80.70?(5)° between the five-membered ring and the pendent benzene ring to which it is attached. Similarly, the acetate residues are twisted with respect to the benzene ring to which they are attached [C—O(carb­oxy)—C—C torsion angles = ?70.24?(14), ?114.43?(10) and ?72.54?(13)°]. In the crystal, a three-dimensional architecture is sustained by C—H?O inter­actions which encompass channels in which the disordered ethyl acetate mol­ecules reside.

Mao, Qinyong; Taylor, Dennis K.; Ng, Seik Weng; Tiekink, Edward R. T.

2013-01-01

108

Preparation of novel carbon microfiber/carbon nanofiber-dispersed polyvinyl alcohol-based nanocomposite material for lithium-ion electrolyte battery separator.  

PubMed

A novel nanocomposite polyvinyl alcohol precursor-based material dispersed with the web of carbon microfibers and carbon nanofibers is developed as lithium (Li)-ion electrolyte battery separator. The primary synthesis steps of the separator material consist of esterification of polyvinyl acetate to produce polyvinyl alcohol gel, ball-milling of the surfactant dispersed carbon micro-nanofibers, mixing of the milled micron size (~500 nm) fibers to the reactant mixture at the incipience of the polyvinyl alcohol gel formation, and the mixing of hydrophobic reagents along with polyethylene glycol as a plasticizer, to produce a thin film of ~25 ?m. The produced film, uniformly dispersed with carbon micro-nanofibers, has dramatically improved performance as a battery separator, with the ion conductivity of the electrolytes (LiPF6) saturated film measured as 0.119 S-cm(-1), approximately two orders of magnitude higher than that of polyvinyl alcohol. The other primary characteristics of the produced film, such as tensile strength, contact angle, and thermal stability, are also found to be superior to the materials made of other precursors, including polypropylene and polyethylene, discussed in the literature. The method of producing the films in this study is novel, simple, environmentally benign, and economically viable. PMID:23827627

Sharma, Ajit K; Khare, Prateek; Singh, Jayant K; Verma, Nishith

2012-12-31

109

The development and characterization of degradable poly(vinyl ester) and poly(vinyl ester)/PEO block copolymers  

NASA Astrophysics Data System (ADS)

The development of biodegradable materials is a challenging and important problem in polymer science. A review of the state of the art in degradable materials is presented, which reveals that current biodegradable materials do not exhibit the thermal or mechanical properties necessary for widespread applications. One strategy for toughening polymeric materials, which has previously been applied to non-degradable thermoplastics and thermoplastic elastomers, is the formation of block copolymers. Poly(vinyl esters) (PVE) homopolymers are known to have a wide range of properties, but PVE block copolymers comprise a class of inexpensive and (bio)degradable materials that were previously unknown. Therefore, the synthesis and properties of these block copolymers were explored in an effort to develop robust degradable materials. This thesis research probes the reaction conditions necessary for the reversible-addition fragmentation chain transfer (RAFT) polymerization and chain extension reactions of vinyl ester monomers. PVE di- and triblock copolymers are synthesized and studied, and the triblock copolymers display extremely poor toughness due to their relatively low molecular weights in light of the high entanglement molecular weight of the poly(vinyl acetate) center block. Attempts to improve the mechanical properties of these materials focus on the incorporation of poly(ethylene oxide) (PEO) as a low entanglement molecular weight and biocompatible center block in PVE-containing triblock copolymers. Depending on the choice of PVE endblocks and the overall polymer composition, crystallization of the PEO block can be controlled, confined, or inhibited. Polymers in which PEO crystallization is completely inhibited exhibit enhanced mechanical properties and behave as weak thermoplastics. In order to understand the relationship between the inhibition of PEO crystallization and the mechanical properties of PVE/PEO materials, these polymers were studied using dynamic mechanical spectroscopy, wide angle X-ray scattering, small angle X-ray scattering, differential scanning calorimetry, and uniaxial tensile tests. By combining insights gained from these techniques, a complex picture emerges that explains the enhanced mechanical properties of these materials based on the type and location of thermal transitions, amorphous PEO entanglements, and the strain-induced crystallization of PEO. This work represents an important step toward developing robust materials with tunable properties containing (bio)degradable components.

Lipscomb, Corinne Elizabeth

110

Superconducting films made by spin-coating of acetate solutions  

SciTech Connect

Metallic silver substrates were spin-coated with several layers of mixed acetate solutions containing bismuth, lead, strontium, calcium, and copper. The viscosities of the cation solutions were modified by the addition of polyvinyl alcohol. The films were heat treated at various temperatures in air, O{sub 2}, and 1% O{sub 2} (balance N{sub 2}) atmospheres. Bismuth cuprate films with transport critical current densities {approx}500 A/cm{sup 2} were obtained in this work. New conditions of coating and sintering have been tried to produce superconducting films.

Balachandran, U.; Poeppel, R.B. (Argonne National Lab., IL (USA)); dos Santos, D.I.; Carvalho, C.L.; da Silva, R.R.; Aegerter, M.A. (Sao Paulo Univ., Sao Carlos, SP (Brazil). Inst. de Fisica e Quimica)

1990-12-01

111

Complex compound polyvinyl alcohol-titanic acid/titanium dioxide  

NASA Astrophysics Data System (ADS)

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

Prosanov, I. Yu.

2013-02-01

112

Polylactic acid\\/cellulose whisker nanocomposites modified by polyvinyl alcohol  

Microsoft Academic Search

The aim of this study was to produce biodegradable polylactic acid\\/cellulose whisker nanocomposites by compounding extrusion and investigate the possibility to use polyvinyl alcohol to improve the dispersion of whiskers in the matrix. Two feeding methods of polyvinyl alcohol and cellulose nanowhiskers were used and evaluated, dry-mixing with polylactic acid prior extrusion or pumping as suspension directly into the extruder.

Daniel Bondeson; Kristiina Oksman

2007-01-01

113

Solution spinning of a high-? oxide superconductor: the effect of poly(vinyl alcohol) spinning medium on the critical current density of melt-processed ? superconducting filaments  

Microsoft Academic Search

The precursor 0953-2048\\/9\\/12\\/014\\/img9 filament was prepared by solution spinning through a homogeneous aqueous poly(vinyl alcohol) (PVA) solution of Y, Ba and Cu acetates. The solution spinning was successfully performed using PVA with degrees of polymerization (DP) of 1700 and 2450 and a degree of saponification of 85 mol%. The as-drawn filament was heated to remove volatile components and partially melted

Hisayo Tomita; Makoto Sunohara; Tomoko Goto; Kiyohisa Takahashi

1996-01-01

114

Solution spinning of high-? oxide superconductors: part VII. The effect of polyvinyl alcohol spinning medium on the sintering of ? superconducting filaments  

Microsoft Academic Search

As basic research for the solution spinning of high-0953-2048\\/9\\/5\\/005\\/img8 oxide superconductor, the effect of poly(vinyl alcohol) (PVA) spinning medium on the sintering of 0953-2048\\/9\\/5\\/005\\/img9 filament was examined. A precursor filament was produced by dry-spinning starting from a homogeneous aqueous PVA solution of Y, Ba and Cu acetates. The as-drawn filament was pyrolysed to remove volatile components and sintered to generate

Hisayo Tomita; Tomoko Goto; Kiyohisa Takahashi

1996-01-01

115

Dielectric Properties of Polyvinyl Alcohol, Poly(methyl Methacrylate), Polyvinyl Butyral Resin and Polyimide at Low Temperatures  

Microsoft Academic Search

Performance of materials and their compatibility determine the size of the electrical insulation in power equipment. For this reason dielectric properties of electrical insulation materials are needed for low temperature power applications. In this work we report the dielectric properties of four polymers: polyvinyl alcohol (PVA), poly(methyl methacrylate) (PMMA), polyvinyl butyral resin (PVB), and polyimide (PI-Kapton®). The dielectric measurements are

Enis Tuncer; Isidor Sauers; David Randy James; Alvin R. Ellis

2008-01-01

116

DIELECTRIC PROPERTIES OF POLYVINYL ALCOHOL, POLY(METHYL METHACRYLATE), POLYVINYL BUTYRAL RESIN AND POLYIMIDE AT LOW TEMPERATURES  

Microsoft Academic Search

Performance of materials and their compatibility determine the size of the electrical insulation in power equipment. For this reason dielectric properties of electrical insulation materials are needed for low temperature power applications. In this work we report the dielectric properties of four polymers: polyvinyl alcohol (PVA), poly(methyl methacrylate) (PMMA), polyvinyl butyral resin (PVB), and polyimide (PI–Kapton®). The dielectric measurements are

Enis Tuncer; Isidor Sauers; D. Randy James; Alvin R. Ellis

2008-01-01

117

Process for the extrusion of compositions comprising polypropylene, polyvinyl alcohol and a polypropylene-polyvinyl alcohol adhesive  

SciTech Connect

This patent describes a process for extruding a composition comprising polyvinyl alcohol, a polypropylene-polyvinyl alcohol adhesive and a plypropylene prepared with a high activity polymerization catalyst. The improvement consists of utilizing polypropylene having from about 50 to about 5000 ppm by weight of hydrotalcite incorporated therein to substantially eliminate gel formation.

Derrick, W.E.

1989-04-18

118

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

NASA Astrophysics Data System (ADS)

Polyvinyl alcohol and polyvinyl pyrrolidone (PVA-PVP) blended hydrogel for wound dressing has been prepared by using gamma rays irradiation technique. The gel fraction, mechanical properties, the water content and water absorption performance of the hydrogels were measured. It was found that the gel fraction increases with increasing irradiation dose but never reaches 100% of gel. The PVA/PVP blended hydrogel has a water content in the range between 60% and 80% and water absorption between 40% and 250%. The water vapor transmission rate value (WVTR) of the PVA/PVP blended hydrogel varies between 50 and 200g/m2/h. The hydrogel could be considered as good barrier against microbes. According to in vitro assessment it was found that the PVA/PVP blended hydrogel was very useful material that can meet the efficacy requirement and its healing rate was comparable with sterilized gauze and sofratulle.

Razzak, M. T.; Darwis, D.; Zainuddin,; Sukirno,

2001-07-01

119

How To Learn and Have Fun with Poly(Vinyl Alcohol) and White Glue  

NASA Astrophysics Data System (ADS)

The general behavior of Newtonian, shear-thinning, shear-thickening, thixotropic, negative thixotropic, and viscoelastic fluids is characterized and briefly discussed in terms of existing theoretical models. Whenever possible, examples of these types of fluids taken from everyday life are given for better understanding. This theoretical introduction is the basis for same, simple, and inexpensive laboratory work employing no special glassware and generally done by pairs of students. The work involves the synthesis of two well-known viscoelastic materials displaying unique properties: poly(vinyl alcohol) (PVA) and white glue, a poly(vinyl acetate)-based emulsion. The students are asked to perform a series of representative mechanical tests on both gels and to describe their observations in full detail. In particular, they are expected to recognize and identify the origin of the intriguing behaviors found (elasticity, spinability, self-siphoning effect, die-swell effect, Weissenberg effect). The tests include the preparation of fibers by extrusion, introducing concepts such as water solubility, hydrogen bonding, and glass transition temperature. The long list of questions, which ideally should be answered at the end of the laboratory work, allows the students to apply the new concepts acquired.

de Zea Bermudez, V.; Passos de Almeida, P.; Féria Seita, J.

1998-11-01

120

Impacts of impregnation with boron compounds on the bonding strength of wood materials  

Microsoft Academic Search

The objective of this research was to evaluate bonding strength of poly(vinyl acetate) (PVAc), polyurethane based Desmodur-VTKA (D-VTKA), phenol–formaldehyde (PF) and melamine–formaldehyde (MF) adhesives to impregnated wood materials. For this purpose, oriental beech (Fagus orientalis lipsky), white oak (Quercus petraea spp.), Uludag fir (Abies bornmülleriana Mattf.) and poplar (Populus nigra) woods were impregnated with borax (Bo), boric acid (Ba), Bo+Ba

Ayhan Özçifçi

2008-01-01

121

Impacts of impregnation chemicals on combustion properties of the laminated wood materials produced combination of beech and poplar veneers  

Microsoft Academic Search

The aim of this study was to investigate the effects of impregnation with boron compounds Borax (BX), Boric acid (BA), BX+BA, Imersol-Aqua (IAQUA) and Timbercare-Aqua (TAQUA) on combustion properties of the laminated wood materials produced combination of Oriental beech and poplar veneers bonded with Desmodur-VTKA (DV) and Poly(vinyl acetate) (PVAc) adhesives. The test samples, prepared from beech (Fagus orientalis Lipsky)

Hakan Keskin; Musa Atar; Mahmut Izciler

2009-01-01

122

Volume shrinkage characteristics in the cure of low-shrink unsaturated polyester resins  

Microsoft Academic Search

The effects of four low-profile additives (LPA), namely poly(vinyl acetate) (PVAc), poly(methyl methacrylate) (PMMA), thermoplastic polyurethane (PU), and polystyrene (PS), on volume shrinkage in the cure of unsaturated polyester (UP) resins at 110°C were investigated by the linear shrinkage method, density measurements, and dilatometry. Experimental results showed that, for the finally cured samples, the fractional volume shrinkage would generally decrease

Yan-Jyi Huang; Chiou-Ming Liang

1996-01-01

123

Polyvinyl alcohol membranes as alkaline battery separators  

SciTech Connect

Polyvinyl alcohol (PVA) cross-linked with aldehyde reagents yields membranes that demonstrate properties that make them suitable for use as alkaline battery separators. Film properties can be controlled by the choice of cross-linker, cross-link density and the method of cross-linking. Three methods of cross-linking and their effects on film properties are discussed. Film properties can also be modified by using a copolymer of vinyl alcohol and acrylic acid as the base for the separator and cross-linking it similarly to the PVA. Fillers can be incorporated into the films to further modify film properties. Results of separator screening tests and cell tests for several variations of PBA films are discussed.

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

1982-01-01

124

Fabrication of polyvinyl alcohol coated polystyrene shells  

SciTech Connect

Glass shells have been used traditionally as the deuterium--tritium fuel container for direct-drive laser fusion experiments because of their convenience and availability, but lower-Z fuel containers have superior implosion characteristics and diagnostic possibilities. Unfortunately, polymers such as polystyrene (PS) that produce shells easily have very high permeabilities so require cryogenics to retain fuel, and impermeable polymers such as polyvinyl alcohol (PVA) are difficult to make into high-quality shells. We have developed improved methods of making PS shells with diameters from 0.2 to 0.7 mm and coating them with a 3-..mu..m layer of PVA to obtain the advantages of both. Both the PS shells and the PVA coating are made in drop towers using gas-stripped nozzles. Details of the procedures and product quality are discussed.

Burnham, A.K.; Grens, J.Z.; Lilley, E.M.

1987-11-01

125

[Survey of plasticizers in polyvinyl chloride toys].  

PubMed

Plasticizers in 101 samples of polyvinyl chloride (PVC) toys on the Japanese market were surveyed. No phthalates were detected in designated toys, though bis(2-ethylhexyl)phthalate, diisononyl phthalate, diisobutyl phthalate, dibutyl phthalate, diisodecyl phthalate and benzyl butyl phthalate were detected in more than half of other toys. 2,2,4-Tributyl-1,3-pentanediol diisobutylate, o-acetyl tributyl citrate, adipates and diacetyl lauroyl glycerol, which are alternative plasticizers to phthalates, were detected. The results of structural analysis confirmed the presence of di(2-ethylhexyl)terephthalate, tributyl citrate, diisononyl 1,2-cyclohexanedicarboxylate and neopentyl glycol esters; these have not previonsly been reported in Japan. There appears to be a shift in plasticizers used for designated toys from phthalates to new plasticizers, and the number of different plasticizers is increasing. PMID:22450665

Abe, Yutaka; Yamaguchi, Miku; Mutsuga, Motoh; Hirahara, Yoshichika; Kawamura, Yoko

2012-01-01

126

Poly(vinyl alcohol)/CNT composites: An effect of cross-linking with glutaraldehyde  

NASA Astrophysics Data System (ADS)

We propose a new method of preparation of the cross-linked composites of poly(vinyl alcohol) (PVA) with carbon nanotubes (CNTs), in which the formation of new covalent bonds does not involve the nanotube entities, but instead PVA macromolecules only. The method consists in the addition of glutaraldehyde to PVA/CNT dispersions in order to cross-link PVA chains via an acetalization reaction. The composites prepared were studied by scanning electron microscopy, atomic force microscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy and thermogravimetric analysis. The addition of 0.5 and 1% of single-walled and multi-walled CNTs (SWNTs and MWNTs, respectively) considerably changes the morphology and thermal stability characteristics of the glutaraldehyde cross-linked PVA. The use of SWNTs is believed to be more advantageous due to their better dispersion within the PVA phase as compared to MWNTs.

Basiuk, Elena V.; Anis, Arfat; Bandyopadhyay, Sri; Alvarez-Zauco, Edgar; Chan, Sammy L. I.; Basiuk, Vladimir A.

2009-07-01

127

Synthesis and sorption properties of porous layers of cyclames on a modified polyvinyl chloride surface  

NASA Astrophysics Data System (ADS)

The structure and adsorption properties of the porous layers of synthesized ethanol-cyclames and sodium acetate cyclames on a surface of polyvinyl chloride (PVC) encapsulating fibers of the asbestos tissue of chrysotile asbestos are studied. It is established that PVC is linked to the silicon-oxygen chains of magnesium hydrosilicate; the capsule ensures the stability of the asbestos tissue under the action of the concentrated solutions of acids and alkalis; its exterior reproduces the fiber surface and has a typical microrelief; and there are voids in the layers. We conclude that the specific surface of layers and the volume of the adsorption space are larger than those of the initial fibers, and the statistical capacity upon the adsorption of water vapor and polar and nonpolar organic molecules depends on the nature and affinity for cyclames.

Tsivadse, A. Yu.; Fridman, A. Ya.; Morozova, E. M.; Sokolova, N. P.; Voloshchuk, A. M.; Petukhova, G. A.; Bardyshev, I. I.; Gorbunov, A. M.; Polyakova, I. Ya.; Shapokhina, O. P.

2012-03-01

128

Partial specific volume of poly(vinyl acetate-co-vinyl chloride)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

Wohlfarth, Ch.

129

Second virial coefficient of poly(vinyl acetate-co-vinyl chloride)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

Wohlfarth, Ch.

130

Solubility parameter of poly(vinyl acetate-co-vinyl chloride)  

NASA Astrophysics Data System (ADS)

This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

Wohlfarth, Ch.

131

PREPARATION OF POLY(VINYL ACETATE) LATEXES IN LIQUID AND SUPERCRITICAL CARBON DIOXIDE. (R826115)  

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

132

Acetals and Ketals.  

National Technical Information Service (NTIS)

Thirteen open-chain simple cyclic and spirocyclic acetals and ketals were studied. The synthesis of all the cyclic compounds was accomplished by an alcoholysis reaction. The infrared and proton magnetic resonance spectra were measured and correlated. (Aut...

J. Radell R. E. Rondeau

1970-01-01

133

Sodium Acetate Hand Warmers  

NSDL National Science Digital Library

In this activity, sodium acetate hand warmers are used to introduce learners to supersaturated solutions, crystallization, and exothermic reactions. This activity guide includes background information, extension ideas, and resources.

Johnson, Jill

2006-01-01

134

Monitoring Vinyl Chloride Around Polyvinyl Chloride Fabrication Plants.  

National Technical Information Service (NTIS)

A program to measure vinyl chloride emissions from polyvinyl chloride fabrication plants was carried out. Four charcoal collectors were stationed around each of five PVC fabrication plants. 24-hour samples were collected daily for 14 days around each plan...

1975-01-01

135

21 CFR 175.270 - Poly(vinyl fluoride) resins.  

Code of Federal Regulations, 2010 CFR

...fluoride) resins consist of basic resins produced by the polymerization of...The poly(vinyl fluoride) basic resins have an intrinsic viscosity...technical grade. (2) Solution. Powdered resin and solvent are heated at...

2010-01-01

136

Compatibility of Polyvinyl Chloride Filter Bags with Chloroform Vapors.  

National Technical Information Service (NTIS)

A determination is made on the compatibility of polyvinyl chloride (PVC) filter bags when exposed to chloroform vapors resulting from offgassing of contaminated adsorbent filters. The objectives of this investigation were to estimate the concentrations of...

C. J. Karwacki

1997-01-01

137

Formalized Poly(Vinyl Alcohol) Membranes for Reverse Osmosis.  

National Technical Information Service (NTIS)

The permeation properties of formalized poly(vinyl alcohol) membranes are described. The interest of this work is centered on the properties relevant to desalination by reverse osmosis. These membranes, when properly prepared, showed reasonably high water...

A. V. Tobolsky C. T. Chen M. C. Chen Y. J. Chang

1972-01-01

138

Calorimetric characterization of membrane materials based on polyvinyl alcohol  

Microsoft Academic Search

There is ample scope for modification of polyvinyl alcohol (PVA) to derive diverse range of properties because of the presence\\u000a of hydroxyl group in its chain. In the present work, PVA has been modified to carboxymethylated polyvinyl alcohol (CPVA) —\\u000a a carboxy-functionalized membrane material. Generally the cohesive energy density has incremental influence on the melting\\u000a point and mechanical strength of

G. S. Mukherjee

2009-01-01

139

Preparation and properties of polyvinyl alcohol microspheres  

SciTech Connect

Polyvinyl alcohol (PVA) microspheres, having a size range of approx.150- to 250-..mu..m diameter with 1- to 5-..mu..m wall thickness, have been fabricated using a solution droplet technique. The spheres were developed for possible use on the Lawrence Livermore National Laboratory (LLNL) Inertial Confinement Fusion (ICF) Program. PVA, a polymer chosen based on earlier survey work carried out at KMS Fusion, Inc., has good strength, low hydrogen permeability, is optically transparent, and water soluble. The latter property makes it safe and easy to use in our droplet generator system. A unique dual-orifice droplet generator was used to prepare the spheres. The droplet generator operating conditions and the column processing parameters were chosen using results from our 1-D model calculations as a guide. The polymer microsphere model is an extension of the model we developed to support the glass sphere production. After preparation, the spheres were physically characterized for surface quality, sphericity, wall thickness (and uniformity), and size. We also determined the buckling pressure for both uncoated and CH-coated spheres. Radiation stability to beta decay (from tritium) was evaluated by exposing the spheres to a 7-keV electron beam. The results from these and other physical property measurements are presented in this report.

Campbell, J.H.; Grens, J.Z.; Poco, J.F.; Ives, B.H.

1986-06-01

140

75 FR 55552 - Polyvinyl Alcohol From Taiwan: Preliminary Determination of Sales at Less Than Fair Value and...  

Federal Register 2010, 2011, 2012, 2013

...Administration [A-583-841] Polyvinyl Alcohol From Taiwan: Preliminary Determination...preliminarily determines that sales of polyvinyl alcohol (PVA) from Taiwan are being...Dumping Duty Investigation: Polyvinyl Alcohol From Taiwan, 69 FR...

2010-09-13

141

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

Federal Register 2010, 2011, 2012, 2013

...Administration [A-583-841] Polyvinyl Alcohol from Taiwan: Final Results...the antidumping duty order on polyvinyl alcohol (PVA) from Taiwan. For these...1\\ See Polyvinyl Alcohol From Taiwan: Preliminary...

2013-06-24

142

77 FR 14342 - Polyvinyl Alcohol From Taiwan: Correction to Notice of Opportunity To Request Administrative Review  

Federal Register 2010, 2011, 2012, 2013

...International Trade Administration [A-583-841] Polyvinyl Alcohol From Taiwan: Correction to Notice of Opportunity...administrative review of the antidumping duty order on polyvinyl alcohol from Taiwan. See Antidumping or Countervailing...

2012-03-09

143

40 CFR 61.64 - Emission standard for polyvinyl chloride plants.  

Code of Federal Regulations, 2010 CFR

...false Emission standard for polyvinyl chloride plants. 61.64 Section 61.64 ...National Emission Standard for Vinyl Chloride § 61.64 Emission standard for polyvinyl chloride plants. An owner or operator of a...

2010-07-01

144

40 CFR 61.64 - Emission standard for polyvinyl chloride plants.  

Code of Federal Regulations, 2010 CFR

...false Emission standard for polyvinyl chloride plants. 61.64 Section 61.64 ...National Emission Standard for Vinyl Chloride § 61.64 Emission standard for polyvinyl chloride plants. An owner or operator of a...

2009-07-01

145

76 FR 29527 - National Emission Standards for Hazardous Air Pollutants for Polyvinyl Chloride and Copolymers...  

Federal Register 2010, 2011, 2012, 2013

...proposed polyvinyl chloride and copolymers (PVC) production rules in the Houston, Texas...http://www.epa.gov/ttn/atw/pvc/pvcpg.html...psia--pounds per square inch absolute PVC--polyvinyl chloride and copolymers...

2011-05-20

146

Oxime Acetates: Substrates for Acetylcholinesterase.  

National Technical Information Service (NTIS)

Oxime acetates function as typical substrates for acetylcholinesterase (AChE). Both syn 3- and syn 4-PAM acetates are rapidly hydrolyzed. Both are highly water soluble and give large changes in molar absorbance upon hydrolysis. Hence, they have potential ...

G. M. Steinberg J. P. Maddox L. J. Szafraniec L. M. Berkowitz N. C. Thomas

1971-01-01

147

Complexes of polyvinyl alcohol with insoluble inorganic compounds  

NASA Astrophysics Data System (ADS)

Hybrid materials of polyvinyl alcohol-hydroxides/oxides of Be, Mg, Zn, Cd, B, Al, Cr, and Fe have been obtained. The studies have been carried out by the methods of optical spectroscopy, X-ray diffraction, and synchronous thermal analysis. Interpretation of experimental data is presented, presuming that, in systems with zinc, boron, aluminum, chromium, and iron hydroxides/oxides, interpolymeric complexes of polyvinyl alcohol with corresponding polymeric inorganic compounds are formed. They belong to a new class of materials with unusual structure containing chains of inorganic polymers isolated in the organic matrix.

Prosanov, I. Yu.; Bulina, N. V.; Gerasimov, K. B.

2013-10-01

148

Kallolide A acetate pyrazoline  

PubMed Central

In the crystal structure of kallolide A acetate pyrazoline [systematic name: 7-methyl-16-oxo-4,10-bis­(prop-1-en-2-yl)-17,18-dioxa-14,15-diaza­tetra­cyclo­[9.4.2.16,9.01,12]octa­deca-6,8,14-trien-5-yl acetate], C23H28N2O5, there is a 12-member­ed carbon macrocyclic structure. In addition, there is a tris­ubstituted furan ring, an approximately planar ?-lactone ring [maximum deviation of 0.057?(3)?Å] and a pyraz­oline ring, the latter in an envelope conformation. The pyrazoline and the ?-lactone rings are fused in a cis configuration. In the crystal, mol­ecules are linked by weak C—H?O inter­actions, forming a two-dimensional network parallel to (001). An intra­molecular C—H?O hydrogen bond is also present.

Rodriguez-Escudero, Idaliz; Marrero, Jeffrey; Rodriguez, Abimael D.

2012-01-01

149

Plasma acetate turnover and oxidation.  

PubMed Central

Plasma acetate turnover and oxidation were determined in 11 healthy subjects by the constant infusion of a trace amount of [1-14C]acetate for 6 h. The subjects ages ranged from 22 to 57 yr. There was a positive correlation (P less than 0.001) between plasma acetate concentration and turnover rate, and a negative correlation (P less than 0.001) between turnover and age. The plasma acetate concentration in the subjects 22--28 yr old was 0.17 vs. 0.13 mM (P less than 0.02) in subjects 40--57 yr old. The plasma acetate turnover rate was also greater in the younger age group (8.23 +/- 0.66 vs. 4.98 +/- 0.64 mumol/min . kg, P less than 0.01). Approximately 90% of the plasma acetate turnover was immediately oxidized to CO2 in both age groups, however, 13.2 +/- 0.89% of the CO2 output in the younger group was derived from plasma acetate oxidation compared to 7.9 +/- 0.94% in the older group (P less than 0.01). The mean plasma acetate concentration, turnover, and oxidation in six cancer patients 47--63 yr old were similar to the values observed in the age-matched healthy subjects. Uptake or output of acetate by various tissues was measured by arterial-venous plasma acetate concentration differences. In seven of eight subjects undergoing elective surgery, the arterial-portal venous concentration difference was negative, which indicated that the gastrointestinal tract can contribute to plasma acetate production. Uptake of plasma acetate by both the leg and liver appeared to be dictated by the arterial acetate concentration. Net production of acetate by both the leg and liver was most often observed at arterial plasma acetate concentrations less than 0.08 mM.

Skutches, C L; Holroyde, C P; Myers, R N; Paul, P; Reichard, G A

1979-01-01

150

Color Stabilization of Polyvinyl Chloride) with Heat Treatment  

Microsoft Academic Search

Stabilization of polyvinyl chloride) (PVC) containing metal soaps was investigated by psychophysical colorimetry. A color difference observed among heated PVC films containing various metal salts depends on coloration of the ?-complex of polyene with metal chloride converted from the metal salt added and that the stabilization effect of synergistic soaps should be based on an effect of complementary colors set

Takeo Iida; Kunio Goto

1978-01-01

151

Review of the oral toxicity of polyvinyl alcohol (PVA)  

Microsoft Academic Search

Polyvinyl alcohols (PVA) (CAS no. 9002-89-5) are synthetic polymers used in a wide range of industrial, commercial, medical and food applications. The purpose of this review, this critical evaluation of the available information on PVA, is to support the safety of PVA as a coating agent for pharmaceutical and dietary supplement products. All the available information on PVA gleaned from

C. C DeMerlis; D. R Schoneker

2003-01-01

152

Vaginal Absorption of Polyvinyl Alcohol in Fischer 344 Rats  

Microsoft Academic Search

Polyvinyl alcohol (PVA) is a polymer with a wide range of molecular weights and uses. Recently, low molecular weight formulations of PVA have been used as components of contraceptive products designed for intravaginal administration in human females. Previous studies in animals have determined that little or no absorption of PVA occurs from the gastrointestinal (GI) tract. However, there is some

J. M. Sanders; H. B. Matthews

1990-01-01

153

Anammox sludge immobilized in polyvinyl alcohol (PVA) cryogel carriers  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study evaluated the use of polyvinyl alcohol (PVA) cryogels to encapsulate slow-growing anammox bacteria for deammonification treatment of wastewater. The cryogel pellets were prepared by a freezing-thawing procedure at -8 oC. On average, pellets contained 11.8 mg TSS/g-pellet of enriched anamm...

154

Immobilization of enzymes in photochemically cross-linked polyvinyl alcohol  

Microsoft Academic Search

Invertase and amyloglucosidase were entrapped in polyvinyl alcohol membranes through UV irradiation of pendent styrylpyridinium groups. The influence of cross-linking on immobilization efficiency was studied using prepolymers with varied cross-linker density, the above mentioned enzymes of different molecular weight, and various substrates. It was found that the larger enzyme invertase is effectively immobilized even in polymers with very low contents

Thomas Uhlich; Mathias Ulbricht; Georg Tomaschewski

1996-01-01

155

Biodegradation of a polyvinyl alcohol-starch blend plastic film  

Microsoft Academic Search

Attempts were made to elucidate the degradation mechanism of a polyvinyl alcohol (PVA)-starch blend plastic. A part of the starch fraction of this plastic was dissolved into an aqueous phase in a control test. Treatment with a PVA-degrading bacterium or enzyme gave a maximal weight loss of approximately 70% and film breakage occurred. Since this plastic contains 40% PVA, it

Tomonori Ishigaki; Yasunori Kawagoshi; Michihiko Ike; Masanori Fujita

1999-01-01

156

Immobilization of microbial cells using polyvinyl alcohol (PVA) — polyacrylamide gels  

Microsoft Academic Search

A novel cell immobilization technique is developed in which polyvinyl alcohol is crosslinked with boric acid with addition of an acrylamide as a polymerizing agent. The presence of the polymerizing agent overcomes the problem of swelling of PVA gels in aqueous solution. The new immobilization method was used to entrap a phenol-degrading microorganism, a species of Pseudomonas. Phenol was successfully

Wang Jianlong; Hou Wenhua; Qian Yicr

1995-01-01

157

Polyvinyl Alcohol from Taiwan. Investigation No. 731-TA-1088 (Preliminary).  

National Technical Information Service (NTIS)

The United States International Trade Commission (ITC) determined that there is not a reasonable indication that a U.S. industry is materially injured or threatened with material injury by reason of imports of polyvinyl alcohol from Taiwan that are allege...

2004-01-01

158

Crack formation in polyvinyl chloride coatings on underground pipes  

Microsoft Academic Search

and certain other agents, for a polymeric coating on a tube in the soil, other specific features are also characteristic. Results have previously been presented [1, 2] of a study of polyvinyl chloride coatings kept for a prolonged period under different underground conditions. The investigations were concerned with oxidative processes under the influence of the molecular oxygen of the air

B. I. Borisov; CHLORIDE COATINGS

1975-01-01

159

Hot pin welding of thin poly(vinyl chloride) sheet  

Microsoft Academic Search

This paper develops a method of welding two thin sheets of poly(vinyl chloride) (PVC) with a heated pin, thus allowing construction of a relationship between the weld temperature and weld strength. Constructing a relationship between weld strength and temperature is necessary for modeling many welding processes, including laser transmission welding. An experimental approach to establishing this relationship is required because

James D. Van de Ven; Arthur G. Erdman

2007-01-01

160

Influence of urea on polyvinyl alcohol molecular superstructure formation  

NASA Astrophysics Data System (ADS)

Whiskers up to 1 cm in length were grown in polyvinyl alcohol (PVA) and urea solution. Raman and IR spectra discover an interaction between PVA and urea molecules. Optical and electronic microscopy data show that urea influences on PVA molecular superstructure formation. PVA whiskers prepared in urea solution can be used for organic semiconductors production which properties are determined by arrangement of polymer macromolecules.

Prosanov, I. Yu.; Matvienko, A. A.; Bokhonov, B. B.

2011-06-01

161

EXPOSURE TO CHEMICAL ADDITIVES FROM POLYVINYL CHLORIDE POLYMER EXTRUSION PROCESSING  

EPA Science Inventory

This report presents a model to predict worker inhalation exposure due to off-gassing of additives during polyvinyl chloride (PVC) extrusion processing. ata on off-gassing of additives were reviewed in the literature, the off-gassing at normal PVC processing temperatures was stud...

162

High-rate thermomechanical behavior of poly(vinyl chloride) and plasticized poly(vinyl chloride)  

NASA Astrophysics Data System (ADS)

A combined experimental and analytical investigation was carried out in order to develop predictive capabilities for the rate-dependent behavior of poly(vinyl chloride) (PVC) and a dioctyl phthalate (DOP)-plasticized PVC, with focus on predicting the thermo-mechanically coupled behavior under high rates of deformation. The two materials were studied experimentally using both dynamic mechanical analysis (DMA) and compression testing over a wide range of strain rates (10 - 4 s - 1 to 2000 s - 1). DMA testing revealed both an ? -transition and a low-temperature ? -transition (-56circC) in the neat PVC; the incorporation of 20wt% DOP in PVC reduced the ? -transition temperature by 54circC, and also suppressed the ? -transition peak. In compression testing, rate-sensitivity transitions were observed in both the neat PVC and the PVC-20wt% DOP compound. The transition in PVC is attributed to the shift of the ? -transition, whereas the transition in the 20wt% DOP blend is due to the rubbery-to-glassy transition as the deformation rate goes from low to high. A constitutive model for the finite strain deformation of amorphous polymers, introduced elsewhere [1,2] and tailored here for the two material systems of interest, is shown to capture the large deformation stress-strain behavior at all rates tested.

Mulliken, A. D.; Soong, S. Y.; Boyce, M. C.; Cohen, R. E.

2006-08-01

163

Acetate metabolism in Methanosarcina barkeri  

Microsoft Academic Search

Methanosarcina barkeri was grown by acetate fermentation in complex medium (N2 gas phase). The molar growth yield was 1.6–1.9 g cells\\/mol methane formed. Under these conditions 63–82% of the methane produced byMethanosarcina strains was derived from the methyl carbon of acetate, indicating that some methane was derived from other media components. Growth was not demonstrated in complex media lacking acetate

P. J. Weimer; J. G. Zeikus

1978-01-01

164

[Nomegestrol acetate: clinical pharmacology].  

PubMed

Progestogens are used in clinical practice in some conditions. Their effects depend on their chemical structure, pharmacokinetics, pharmacodynamics, with important differences among various progestogens. Generally, progestins are classified according to their parent molecule, of which often they keep some features. Derivatives of 19-nor-progesterone are characterized by high selectivity of action on progestin receptor. In particular, nomegestrol acetate (NomAc) shows an important progestational potency, neutral gluco-lipid profile, and antigonadotropic activity. It is used for treating menstrual cycle disorders and for hormone replacement therapy in menopause in association with an estrogen. In future, thanks to its antigonadotropic activity, NomAc will be used in estroprogestin combinations in fertile women, thus taking advantage of its tolerability profile and obtaining numerous non-contraceptive benefits as well. PMID:19749678

Lello, S

2009-10-01

165

Clay flocculation improved by cationic poly(vinyl alcohol)/anionic polymer dual-component system.  

PubMed

The synthesis of cationically modified poly(vinyl alcohol), CPVA, by copolymerization of vinyl acetate and diallyldimethyl ammonium chloride (DADMAC), followed by alkaline hydrolysis was systematically studied. The application of the resulting polymer to the fine clay flocculation was also reported. The charge density and the structure of the resulting CPVA were characterized by polyelectrolyte titration and NMR. A photometric dispersion analyzer was used to conduct the dynamic flocculation experiments. Under fine clay experimental conditions, the CPVA alone contributed little to inducing clay flocculation. However, in conjunction with anionic polyacrylamide-based polymer with high molecular weight and low charge density, significant improvement in the flocculation of fine clay particles was achieved. The influence of factors such as pH and shear force on clay flocculation was also investigated to identify optimum application conditions for clay flocculation. The electrostatic interactions between the clay and CPVA, as well as those between the CPVA pre-treated clay and anionic polymer, were studied to explore the flocculation mechanism. PMID:18657822

Sang, Yizhou; Xiao, Huining

2008-07-05

166

Selective removal of caffeine from tea extracts using macroporous crosslinked polyvinyl alcohol adsorbents.  

PubMed

The hydrolysis reaction of ester groups in vinyl acetate (VAc) was used to introduce hydroxyl groups into the matrix of a macroporous adsorbent, which was itself prepared by free radical suspension copolymerization of triallyl isocyanurate (TAIC) and VAc. Therefore, the copolymerization incompatibility between the hydrophilic and the hydrophobic monomer was overcome successfully and the hydrophobic matrix of the polymeric adsorbent containing a polyvinyl alcohol (PVA) segment was obtained. Introduction of the PVA segment decreased the hydrophobic adsorption affinity of the adsorbent while producing the hydrogen-bonding interaction. When isolating the two active components, polyphenols (TPh) and caffeine (CAF), from green tea extracts, this polymeric adsorbent, namely poly(TAIC-co-VA), exhibited good adsorption selectivity towards TPh over CAF. The adsorption mechanism leading to this selectivity involved a hydrophobic interaction mechanism for CAF and multiple weak hydrophobic and hydrogen-bonding interactions for TPh. The adsorption thermodynamics for TPh on poly(TAIC-co-VA) were studied. The effects of adsorbent structure and gradient desorption conditions on isolation were investigated. The result showed that adsorbent, with 20% TAIC content, was able to efficiently remove CAF from different tea extracts with different ratios of TPh and CAF. Finally, almost no CAF was detected in the TPh fraction and the recovery of TPh was greater than 95%. PMID:22102370

Ma, Ning; Wang, Peng; Kong, Xia; Shi, Rongfu; Yuan, Zhi; Wang, Chunhong

2011-11-21

167

Polyvinyl alcohol {gamma}-ray grafted nylon 4 membrane for pervaporation and evapomeation  

SciTech Connect

Nylon 4, which possesses high mechanical strength and good affinity for water, can be considered as a liquid separation membrane. To improve the hydrophilicity of a Nylon 4 membrane for pervaporation and evapomeation processes, and to overcome the hydrolysis of polyvinyl alcohol (PVA), this study attempts to prepare a PVA-g-Nylon 4 membrane by {gamma}-ray irradiation grafting of vinyl acetate (VAc) onto Nylon 4 membrane, followed by hydrolysis treatment. The effects of down-stream pressure, irradiation dose, VAc monomer concentration, degree of grafting, feed composition, and size of alcohols on the separation of water-alcohol mixtures were studied. The surface properties of the prepared membrane were characterized by FTIR, ESCA, and a contact angle meter. A separation factor of 13.8 and a permeation rate of 0.352 kg/m{sup 2}-h can be obtained for a PVA-g-Nylon 4 membrane with a degree of grafting of 21.2% for a 90-wt% ethanol feed concentration. Compared to the pervaporation process, the evapomeation process has a significantly increased separation factor with a decreased permeation rate for the same PVA-g-Nylon 4 membrane. 24 refs., 9 figs., 4 tabs.

Lai, J.Y.; Chen, R.Y.; Lee, K.R [Chun Yuan Univ., Chung Li (Taiwan, Province of China)

1993-05-01

168

Thermogravimetric analysis of the relationship among calcium magnesium acetate, calcium acetate and magnesium acetate  

Microsoft Academic Search

Thermal decomposition characteristic of calcium magnesium acetate (CMA), calcium acetate (CA) and magnesium acetate (MA) are investigated through thermogravimetric (TG) analysis at the heating rates of 5Kmin?1, 7.5Kmin?1, 10Kmin?1 and 15Kmin?1. After dehydration, the evaporation of carboxylic radical and carbon dioxide of CMA and CA exist in two separate segments, but for MA, this occurs together in just one segment

Shengli Niu; Kuihua Han; Chunmei Lu; Rongyue Sun

2010-01-01

169

Micropatterned polyvinyl butyral membrane for acid-base diodes.  

PubMed

Until now, polyvinyl alcohol (PVA) gel cylinders have been used in electrolyte diodes as a connecting element between the acidic and alkaline reservoirs. In this paper, a new connecting element is reported: a breath figure templated polyvinyl butyral (PVB) membrane prepared with dip-coating from a dichloromethane solution of the polymer in a humid atmosphere. The procedure gives a 1.5-2 ?m thick membrane with a hexagonal pattern, the average characteristic length of which is 1 ?m. After an acidic etching, it was found to be a good connecting element. The voltage-current characteristics and dynamic properties of PVA and PVB were measured and compared. The PVB membrane has a faster response to voltage changes than the PVA gel, but in both cases, there was a slow drift in the current that prevented it from reaching a steady state. Reproducible characteristics can be obtained, however, after the current reaches a well-defined quasi-steady state. PMID:20929271

Roszol, László; Lawson, Thuy; Koncz, Viktória; Noszticzius, Zoltán; Wittmann, Maria; Sarkadi, Tamás; Koppa, Pál

2010-11-01

170

Cross-linked polyvinyl alcohol films as alkaline battery separators  

Microsoft Academic Search

Cross-linking methods were investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: (1) PVA-dialdehyde blends post-treated with an acid or acid periodate solution (two-step method) and (2) PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid

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

1982-01-01

171

Cross-linked polyvinyl alcohol films as alkaline battery separators  

Microsoft Academic Search

Cross-linking methods have been investigated to determine their effect on the performance of polyvinyl alcohol (PVA) films as alkaline battery separators. The following types of cross-linked PVA films are discussed: PVA-dialdehyde blends post-treated with an acid or acid periodate solution and PVA-dialdehyde blends cross-linked during film formation (drying) by using a reagent with both aldehyde and acid functionality. Laboratory samples

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

1983-01-01

172

Nanophotothermolysis of Poly-(vinyl) Alcohol Capped Silver Particles  

NASA Astrophysics Data System (ADS)

Laser-induced thermal fusion and fragmentation of poly-(vinyl) alcohol (PVA)-capped silver nanoparticles in aqueous medium have been reported. PVA-capped silver nanoparticles with an average size of 15 nm were prepared by chemical reduction technique. The laser-induced photo-fragmentation of these particles has been monitored by UV-visible spectroscopy and transmission electron microscopy. The morphological changes induced by thermal and photochemical effects were found to influence the optical properties of these nanoparticles.

Tripathy, Suraj Kumar

2008-04-01

173

Electrical conductivity of polyvinyl alcohol-multiwall carbon nanotubes composites  

NASA Astrophysics Data System (ADS)

The dc and ac conductivity of polyvinyl alcohol (PVA)-multiwalled carbon nanotube (MWNT) nanocomposites prepared by solution casting were investigated by employing dielectric relaxation spectroscopy in broad frequency range (0.1 Hz-10 MHz) at room temperature as a function of the conductive weight fraction (p) ranging from 0 to 2wt.%. The frequency dependence of the measured conductivity obeys the universal dynamic response (UDR); a dc plateau followed, by the power law above a critical frequency (fc).

Amrin, Sayed; Deshpande, V. D.

2013-06-01

174

Chromate reduction by Microbacterium liquefaciens immobilised in polyvinyl alcohol  

Microsoft Academic Search

A polyvinyl alcohol-based immobilisation technique has been utilised for entrapping the newly-isolated chromate- reducing bacterium, Microbacterium liquefaciensMP30. Three immobilisation methods were evaluated: PVA- nitrate, PVA-borate and PVA-alginate. Chromate reduction was studied in batch and continuous-flow bioreactors, where the beads maintained integrity during continuous operation. PVA-borate and PVA-alginate cell beads showed a higher rate and extent of chromate reduction than PVA-nitrate

P. Pattanapipitpaisal; N. L. Brown; L. E. Macaskie

2001-01-01

175

Surface acoustic wave humidity sensor using polyvinyl-alcohol film  

Microsoft Academic Search

A surface acoustic wave (SAW) sensor has been fabricated and used to study the hygroscopic properties of the polyvinyl-alcohol (PVA) polymer film as layer chemically sensitive to relative humidity (RH). A 42 MHz SAW device has been configured as delay line onto 128° YX-LiNbO3 substrate with the SAW path totally covered by the spin-coated PVA film. The SAW phase response

M. Penza; V. I. Anisimkin

1999-01-01

176

Hybrid material polyvinyl alcohol-stannic acid/stannic oxide  

NASA Astrophysics Data System (ADS)

Hybrid materials polyvinyl alcohol (PVA)-stannic acid and PVA-SnO2 were produced in the form of transparent films. Their investigations by means of optical spectroscopy, X-ray analysis, thermo-gravimetry, and mass-spectrometry were carried out as well as electrical measurements. The model is discussed where the polymeric chains of inorganic constituent are linked by coordinative bonds with carbon polymeric chains. Photoconductivity of PVA-SnO2 was discovered.

Prosanov, I. Yu.; Chesalov, Yu. A.; Gerasimov, K. B.; Bulina, N. V.

2013-07-01

177

Heterogeneous photocatalytic oxidation of polyvinyl alcohol in water  

Microsoft Academic Search

Titanium dioxide mediated photocatalytic degradation of polyvinyl alcohol (PVA) was studied in an annular photoreactor with two 6W (Emax=365nm) UV lamps as light source. In the presence of both TiO2 and light, and initial concentration of 30mg\\/l, 55.3% of PVA was found to degrade after an hour. The effects of initial concentration, pH and the addition of H2O2 on the

Yingxu Chen; Zhenshi Sun; Ye Yang; Qiang Ke

2001-01-01

178

Poly(vinyl alcohol) hydrogels as soft contact lens material  

Microsoft Academic Search

A new type of soft contact lens was developed from the poly(vinyl alchol) (PVA) hydrogel prepared by a low temperature crystallization technique using a water-dimethyl sulfoxide mixed solvent. The PVA contact lens materials had a water content of 78% and a tensile strength of 50 kg\\/cm, five times as strong as that of commercial poly(2-hydroxyethyl methacrylate) soft contact lens. The

Suong-Hyu Hyon; Won-Ill Cha; Yoshito Ikada; Mihori Kita; Yuichiro Ogura; Yoshihito Honda

1994-01-01

179

Chromate reduction by Microbacterium liquefaciens immobilised in polyvinyl alcohol  

Microsoft Academic Search

A polyvinyl alcohol-based immobilisation technique has been utilised for entrapping the newly-isolated chromate-reducing bacterium, Microbacterium liquefaciens MP30. Three immobilisation methods were evaluated: PVA-nitrate, PVA-borate and PVA-alginate. Chromate reduction was studied in batch and continuous-flow bioreactors, where the beads maintained integrity during continuous operation. PVA-borate and PVA-alginate cell beads showed a higher rate and extent of chromate reduction than PVA-nitrate cell

P. Pattanapipitpaisal; N. L. Brown; L. E. Macaskie

2001-01-01

180

Heat capacity of poly(vinyl methyl ether)  

Microsoft Academic Search

The heat capacity of poly(vinyl methyl ether) (PVME) has been measured using adiabatic calorimetry and temperature-modulated differential scanning calorimetry (TMDSC). The heat capacity of the solid and liquid states of amorphous PVME is reported from 5 to 360 K. The amorphous PVME has a glass transition at 248 K (-25 C). Below the glass transition, the low-temperature, experimental heat capacity

Marek Pyda; K. Van Durme; Bernhard Wunderlich; B. Van Mele

2005-01-01

181

Immobilization of enzyme into poly(vinyl alcohol) membrane  

Microsoft Academic Search

Glucoamylase, invertase, and cellulase were entrapped within poly(vinyl alcohol) (PVA) membrane cross-linked by means of irradiation of ultraviolet light. The conditions for immobilization of glucoamylase were examined with respect to enzyme concentration in PVA, sensitizer (sodium benzoate) concentration in PVA, irradiation time, and membrane thickness. Various characteristics of immobilized glucoamylase were evaluated. Among them, the pH activity curve for the

Kiyokazu Imai; Tomoo Shiomi; Kozo Uchida; Masamitsu Miya

1986-01-01

182

Synthesis of a mesoporous silica hollow microsphere using polyvinyl alcohol  

Microsoft Academic Search

A mesoporous silica hollow microsphere was synthesized in the presence of polyvinyl alcohol for the first time. The synthesized material was characterized by various instrumental techniques such as small-angle X-ray scattering, scanning electron microscopy, transmission electron microscopy, N2 adsorption measurement and Fourier transform infrared spectroscopy. I have succeeded in incorporating an Ultraviolet ray absorber, 2, 2´, 4, 4´ tetrahydroxy benzophenone

N. Venkatathri

2008-01-01

183

Influence of urea on polyvinyl alcohol molecular superstructure formation  

Microsoft Academic Search

Whiskers up to 1 cm in length were grown in polyvinyl alcohol (PVA) and urea solution. Raman and IR spectra discover an interaction\\u000a between PVA and urea molecules. Optical and electronic microscopy data show that urea influences on PVA molecular superstructure\\u000a formation. PVA whiskers prepared in urea solution can be used for organic semiconductors production which properties are determined\\u000a by

I. Yu. Prosanov; A. A. Matvienko; B. B. Bokhonov

2011-01-01

184

Dynamic changes in size distribution of emulsion droplets during ethyl acetate-based microencapsulation process.  

PubMed

This study investigated the dynamic effect of the emulsification process on emulsion droplet size in manufacturing microspheres using ethyl acetate as an organic solvent. A dispersed phase consisting of poly(lactide-co-glycolide) and ethyl acetate was emulsified in a poly(vinyl alcohol) aqueous solution for a predetermined time ranging from 2 to 9, 16, 23, 30, 40, 50, or 60 minutes. Ethyl acetate was then quickly extracted to transform emulsion droplets into solidified microspheres, and their size distribution was determined. This experimental design allowed quantification of the size distribution of emulsion droplets over the course of emulsification. When emulsification time was extended from 2 to 60 minutes, the emulsion droplets decreased in size from 98.1 to 50.3 microm and their surface area increased from 0.07 to 0.29 m2/g. Overall, prolonging emulsification time up to 60 minutes resulted in the progressive evolution of smaller emulsion droplets (1-60 microm) and the simultaneous disappearance of larger ones (> 81 microm). Increases in the total number of microspheres and their surface area were caused mainly by continuous fragmentation of emulsion droplets before ethyl acetate extraction. The increase in the smaller microsphere population might also be due in part to shrinkage of microspheres. These results show that the onset of ethyl acetate extraction influenced the kinetics of the breakup and formation of emulsion droplets, thereby affecting to a great extent the size distribution of microspheres. PMID:14727854

Bahl, Y; Sah, H

2000-03-23

185

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

NASA Astrophysics Data System (ADS)

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 Cdbnd 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.

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

2013-07-01

186

Stabilized Calcium Acetate Oil Dispersions.  

National Technical Information Service (NTIS)

A lubricating composition is imparted with improved load-carrying ability and anti-wear properties by incorporation of calcium acetate. The composition consists of a base lubricant, 0.1 to 50 percent by weight calcium acetate and 0.01 to 20 percent by wei...

R. H. Davis

1965-01-01

187

Lead Acetate, Radiotracer Metabolism Study.  

National Technical Information Service (NTIS)

Metabolic studies utilizing radiotracer techniques were applied to tissues from rats which had received 0 and 1000 ppm lead acetate (calculated as lead) for one month prior to the oral administration of 210 lead acetate. Seventy-two hours after administra...

D. C. Jessup

1967-01-01

188

Stimuli-Responsive Mechanically Adaptive Polymer Nanocomposites  

PubMed Central

A new series of biomimetic stimuli-responsive nanocomposites, which change their mechanical properties upon exposure to physiological conditions, was prepared and investigated. The materials were produced by introducing percolating networks of cellulose nanofibers or “whiskers” derived from tunicates into poly(vinyl acetate) (PVAc), poly(butyl methacrylate) (PBMA), and blends of these polymers, with the objective of determining how the hydrophobicity and glass-transition temperature (Tg) of the polymer matrix affect the water-induced mechanically dynamic behavior. Below the Tg (~60–70 °C), the incorporation of whiskers (15.1 – 16.5% v/v) modestly increased the tensile storage moduli (E?) of the neat polymers from 0.6 to 3.8 GPa (PBMA) and from 2 to 5.2 GPa (PVAc). The reinforcement was much more dramatic above Tg, where E? increased from 1.2 to 690 MPa (PVAc) and ~1 to 1.1 GPa (PBMA). Upon exposure to physiological conditions (immersion in artificial cerebrospinal fluid, ACSF, at 37 °C) all materials displayed a decrease of E?. The most significant contrast was seen in PVAc; for example the E? of a 16.5% v/v PVAc/whisker nanocomposite decreased from 5.2 GPa to 12.7 MPa. Only a modest modulus decrease was measured for PBMA/whisker nanocomposite; here the E? of a 15.1% v/v PBMA/whisker nanocomposite decreased from 3.8 to 1.2 GPa. A systematic investigation revealed that the magnitude of the mechanical contrast was related to the degree of swelling with ACSF, which was shown to increase with whisker content, temperature, and polarity of the matrix (PVAc > PBMA). The mechanical morphing of the new materials can be described in the framework of both the percolation and Halpin-Kardos models for nanocomposite reinforcement, and is the result of changing interactions among the nanoparticles and plasticization of the matrix upon swelling.

Shanmuganathan, Kadhiravan; Capadona, Jeffrey R.; Rowan, Stuart J.; Weder, Christoph

2010-01-01

189

DIELECTRIC PROPERTIES OF POLYVINYL ALCOHOL, POLY(METHYL METHACRYLATE), POLYVINYL BUTYRAL RESIN AND POLYIMIDE AT LOW TEMPERATURES  

SciTech Connect

Performance of materials and their compatibility determine the size of the electrical insulation in power equipment. For this reason dielectric properties of electrical insulation materials are needed for low temperature power applications. In this work we report the dielectric properties of four polymers: polyvinyl alcohol (PVA), poly(methyl methacrylate) (PMMA), polyvinyl butyral resin (PVB), and polyimide (PI--Kapton\\textregistered). The dielectric measurements are performed with an electrical impedance analyzer in the frequency domain. The impedances are recorded in a cryocooler in the temperature range from 45K to 350K. The dielectric breakdown characteristics of the polymers are measured in a liquid nitrogen bath at atmospheric pressure. It is observed that PI and \\pmma\\ dissolved in toluene have the lowest dielectric losses for temperatures lower than $100\\ \\kelvin$. \\Blx\\ and PI have the smallest spread in their breakdown strength data.

Tuncer, Enis [ORNL; Sauers, Isidor [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL

2008-01-01

190

Dielectric Properties of Polyvinyl Alcohol, Poly(methyl Methacrylate), Polyvinyl Butyral Resin and Polyimide at Low Temperatures  

NASA Astrophysics Data System (ADS)

Performance of materials and their compatibility determine the size of the electrical insulation in power equipment. For this reason dielectric properties of electrical insulation materials are needed for low temperature power applications. In this work we report the dielectric properties of four polymers: polyvinyl alcohol (PVA), poly(methyl methacrylate) (PMMA), polyvinyl butyral resin (PVB), and polyimide (PI-Kapton®). The dielectric measurements are performed with an electrical impedance analyzer in the frequency domain. The impedances are recorded in a cryocooler in the temperature range from 45 K to 350 K. The dielectric breakdown characteristics of the polymers are measured in a liquid nitrogen bath at atmospheric pressure. It is observed that PI and PMMA dissolved in toluene have the lowest dielectric losses for temperatures lower than 100 K. PVB and PI have the smallest spread in their breakdown strength data.

Tuncer, Enis; Sauers, Isidor; James, D. Randy; Ellis, Alvin R.

2008-03-01

191

21 CFR 175.300 - Resinous and polymeric coatings.  

Code of Federal Regulations, 2010 CFR

... Styrene. Vinyl toluene. (xv) Vinyl resinous substance, as the basic polymers: Polyvinyl acetate. Polyvinyl alcohol. Polyvinyl butyral. Polyvinyl chloride. Polyvinyl formal. Polyvinylidene chloride....

2009-04-01

192

21 CFR 175.300 - Resinous and polymeric coatings.  

Code of Federal Regulations, 2010 CFR

... Styrene. Vinyl toluene. (xv) Vinyl resinous substance, as the basic polymers: Polyvinyl acetate. Polyvinyl alcohol. Polyvinyl butyral. Polyvinyl chloride. Polyvinyl formal. Polyvinylidene chloride....

2010-01-01

193

21 CFR 175.300 - Resinous and polymeric coatings.  

Code of Federal Regulations, 2013 CFR

... Styrene. Vinyl toluene. (xv) Vinyl resinous substance, as the basic polymers: Polyvinyl acetate. Polyvinyl alcohol. Polyvinyl butyral. Polyvinyl chloride. Polyvinyl formal. Polyvinylidene chloride....

2013-04-01

194

21 CFR 184.1185 - Calcium acetate.  

Code of Federal Regulations, 2013 CFR

...also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be produced by the calcium hydroxide neutralization of acetic acid. (b) The ingredient meets the specifications of the Food Chemicals...

2013-04-01

195

Draft Guidance on Norethindrone Acetate Active ingredient ...  

Center for Drug Evaluation (CDER)

Text VersionPage 1. Contains Nonbinding Recommendations Draft Guidance on Norethindrone Acetate ... Active ingredient: Norethindrone Acetate ... More results from www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation

196

Methanogenesis from acetate: enrichment studies.  

PubMed Central

An acetate enrichment culture was initiated by inoculating anaerobic sludge from a mesophilic methane digestor into a mineral salts medium with calcium acetate as the sole carbon and energy source. This enrichment was maintained indefinitely by weekly transfer into medium of the same composition. A study of this enrichment disclosed an unexpected age-dependent inhibition of methanogenesis by H2 and formate which apparently differed from the inhibition by chloroform and benzyl viologen. This age-dependent inhibition indicated that microbial interactions of the mixed enrichment population may play a regulatory role in methane formation. Futhermore, stimulation of methanogenesis in the acetate enrichment by addition of yeast extract showed a nutrient limitation which indicated that syntrophic interactions leading to formation of growth factors may also occur. A model is presented to illustrate the possible interrelationships between methanogenic and nonmethanogenic bacteria in their growth and formation of methane and carbon dioxide from acetate. Images

Baresi, L; Mah, R A; Ward, D M; Kaplan, I R

1978-01-01

197

Molecular Structure of Acetic acid  

NSDL National Science Digital Library

Acetic Acid commonly associated with vinegar; it is the most commercially important organic acid and is used to manufacture a wide range of chemical products, such as plastics and insecticides. Acetic acid is produced naturally by Aceto bacteria but, except for making vinegar, is usually made through synthetic processes. Ethanoic acid is used as herbicide, as a micro-biocide, as a fungicide and for pH adjustment.

2003-06-02

198

Acetate catabolism by Methanosarcina barkeri  

SciTech Connect

Cell suspensions of Methanosarcina barkeri convert the carboxyl and methyl group carbons of acetate to carbon dioxide and methane at pH 6 under an atmosphere of 100% CO/sub 2/. The rate of loss of radioactivity from (1-/sup 14/C)acetate was over three times greater than that from (2-/sup 14/C)acetate under these conditions. Control experiments with both labeled substrates present showed that the rates were additive. Addition of a high level of 2-bromoethanesulfonate to selectively inhibit methane formation largely inhibited release of /sup 14/C from methyl-labeled acetate but only marginally decreased the rate of loss from (1-/sup 14/C)acetate. Thus, in the absence of the inhibitor loss of /sup 14/C from (1-/sup 14/C)acetate likely reflects an isotopic exchange reaction with CO/sub 2/ superimposed on the overall conversion of acetate to CO/sub 2/ and CH/sub 4/. The exchange reaction was inhibited by uncouplers such as 2,4-dinitrophenol, CCCP, and FCCP. Cells permeabilized by treatment with nonionic detergents or disrupted by passage through a French pressure cell failed to catalyze the exchange reaction. Exchange activity was not restored by addition of ATP or by use of (1-/sup 14/C)acetyl CoA as substrate. No evidence for involvement of carbon monoxide dehydrogenase in the exchange was found in these experiments when CO/sub 2/ was replaced by CO. However, the soluble extracts retained the ability to convert acetate to methane in the presence of H/sub 2/ and ATP.

Grahame, D.A.

1987-05-01

199

Catalytic dehydrochlorination of polyvinyl chloride in two-phase systems  

SciTech Connect

The catalytic activity of quaternary ammonium salts (QAS), whose cation and anion structures are different, and the mechanism of catalytic two-phase dehydrochlorination of polyvinyl chloride (PVC) are studied. Under phase-transfer conditions, dehydrochlorination of PVC is shown to proceed at the interface via an ionic mechanism in the presence of quaternary ammonium salts. The catalytic activity of QAS is governed by both the cation lipophilicity and the anion nature and increases as alcohols are introduced into the reaction mixture. The alcohol nature does not influence the extent of the reaction completion, but it does effect the supermolecular structure of the polyacetylene synthesized.

Leplyanin, G.V.; Salimgareeva, V.N.; Sannikova, N.S. [Institute of Organic Chemistry, Ufa (Russian Federation)

1994-11-01

200

Features of IR Holograms recorded on Polyvinyl alcohol films  

SciTech Connect

When holograms are recorded with continuous-wave radiation from a CO/sub 2/ laser in Plexiglas, a diffraction efficiency of about 20% may be attained. Results are presented on pulsed IR holograms recorded on films of polyvinyl alcohol. The holograms are recorded with a TEA CO/sub 2/ laser giving a pulse length of 3 musec. The diffraction-efficiency results are given for holographic gratings having a spatial frequency of 50 mm/sup -1/. The IR recording mechanism related to relief change is evidently characteristic of other polymeric recording media.

Durasov, V.M.; Chatei, A.V.; Rubanov, A.S.; Stashkevich, I.V.

1986-01-01

201

Nanodielectric system for cryogenic applications: Barium titanate filled polyvinyl alcohol  

SciTech Connect

In the current study the focus is on dielectric properties (as a function of frequency and temperature) of a polymeric composite system composed of polyvinyl alcohol and barium titanate nano powder. In the investigations, the temperature range is between 50-295 K, and the frequency range is between $20\\ \\hertz-1\\ \\mega\\hertz$. Polarization and conduction processes are investigated in the linear regime. Dielectric breakdown strengths of samples are also reported. The materials presented have potential to be implemented in cryogenic capacitor or field grading applications.

Tuncer, Enis [ORNL; Sauers, Isidor [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL; Duckworth, Robert C [ORNL

2008-01-01

202

Computational studies of polyvinyl alcohol encapsulated tetrahedral cadmium sulphide cluster  

NASA Astrophysics Data System (ADS)

In the present work theoretical encapsulation of tetrahedral cluster of cadmium sulphide within polyvinyl alcohol (PVA) chains has been studied. Density of states, binding energy and optical properties are calculated using density functional theory (DFT) as implemented in SIESTA code with local density approximation (LDA) functionals. We observe that PVA chains strongly interact with [Cd4(SH)10]2- cluster through-OH groups and results in broadening of the band gap. Absorption spectrum of hybrid structure is also computed which is comparable to experimental results.

Bala, Vaneeta; Tripathi, S. K.; Kumar, Ranjan

2013-06-01

203

Rhamnolipid production by Pseudomonas aeruginosa immobilised in polyvinyl alcohol beads.  

PubMed

A marine bacterium, Pseudomonas aeruginosa BYK-2 (KCTC 18012P), was immobilised by entrapment in 10% (w/v) polyvinyl alcohol beads and optimized for the continuous production of rhamnolipid. The relative activity of rhamnolipid production was maintained at 80 approximately 90% of the initial production during 15 cycles in a repeated batch culture. Continuous culture was performed in a 1.8 1 airlift bioreactor, yielding 0.1 g rhamnolipid h(-1) at a dilution rate of 0.0 18 h(-1), 25 degrees C, initial pH 7, and 0.5 vvm aeration rate with a 1.21 working volume. PMID:15005149

Jeong, Hye-Sung; Lim, Dong-Jung; Hwang, Sun-Hee; Ha, Soon-Duck; Kong, Jai-Yul

2004-01-01

204

Analysis of Antibacterial Action of Polyvinyl Chloride Surface Modified with Gentian Violet  

Microsoft Academic Search

The effect of incorporation of gentian violet into medical-grade polyvinyl chloride was studied in this work. The antibacterial properties of the resulting blend were evaluated and the influence of the amount of gentian violet assessed. Dispersion of the gentian violet in the polyvinyl chloride following the blending of the two components was uniform as was demonstrated by the optical images,

M. Sowe; M. Polaskova; I. Kuritka; T. Sedlacek; M. Merchan

2009-01-01

205

Production and Properties of Polyvinyl Alcohol Spinning Solutions Containing Protease C and Polyhexamethylene Guanidine  

Microsoft Academic Search

Comparative studies of the production conditions and properties of polyvinyl alcohol spinning solutions containing the proteolytic enzyme protease C, the polycationic antimicrobial polyhexamethylene guanidine hydrochloride or polyhexamethylene guanidine phosphate, and in some cases sodium alginate, were conducted. It was found that addition of protease C, polyhexamethylene guanidine hydrochloride, polyhexamethylene guanidine phosphate, and alginate to a polyvinyl alcohol water-alcohol solution, used

E. Yu. Aleshina; T. N. Yudanova; I. F. Skokova

2001-01-01

206

In Situ Self Cross-Linking of Polyvinyl Alcohol Battery Separators.  

National Technical Information Service (NTIS)

A battery separator was produced from a polyvinyl alcohol sheet structure which was subjected to an in situ, self crosslinking process by selective oxidation of the 1,2 diol units present in the polyvinyl alcohol sheet structure. The 1,2 diol units were c...

W. H. Philipp L. C. Hsu D. W. Sheibley

1979-01-01

207

Bacteriorhodopsin oriented in polyvinyl alcohol films as an erasable optical storage medium  

Microsoft Academic Search

Films of oriented bacteriorhodopsin have been formed in polyvinyl alcohol with excellent optical quality. Images with high contrast have been impressed and erased on these films. Second-harmonic microscopy has been used to read the image on a bacteriorhodopsin-polyvinyl alcohol film without erasure. The potential of these films for molecular information storage and computation is discussed.

Zhongping Chen; Hiroyuki Takei; Aaron Lewis; Isaiah Nebenzahl

1991-01-01

208

Histologic Long-term Follow-up after Embolization with Polyvinyl Alcohol Particles  

Microsoft Academic Search

Summary: A large facial vascular malformation was embolized with polyvinyl alcohol particles twice in 8 years. Resected tissue enabled long-term examination of this material, confirming its chemical inertness and revealing minimal tissue reaction to it apart from calcification. No particle migration, fragmentation, or absorption occurred. There was some recanalization of occluded vessels. Most vessels containing polyvinyl alcohol particles, and all

George S. Davidson; Karel G. Terbrugge

209

Preparation of PVP immobilized microporous chlorinated polyvinyl chloride membranes on fabric and their hydraulic permeation behavior  

Microsoft Academic Search

Chlorinated polyvinyl chloride (CPVC)\\/polyvinyl pyrrolidone (PVP) membranes were prepared using the water vapor induced phase separation technique. The surface pore size of the membrane was dependent on the relative humidity (RH) and the PVP content. PVP was used as the pore-forming and wetting agent. However, as PVP could leach during the filtration process, the PVP was immobilized within the CPVC

Jong Seok Kang; Ki Yoen Kim; Young Moo Lee

2003-01-01

210

Microwave reflectivity measurement of silicon urea polyvinyl alcohol \\/ epoxy resin composites in X and Ku bands  

Microsoft Academic Search

In the paper presented here, a thermally stable epoxy resin modified urea - polyvinyl alcohol - silicon blends have been prepared by in situ polymerization technique. For this, the materials were modified with triethylene tetramine (hardener) to obtain highly cross-linked thermosetting resins. The authors have synthesized the polymer composites; silicon-urea-polyvinyl alcohol in three ratios in weight percentages with analytical reagent

M. Murugan; V. K. Kokate

2009-01-01

211

CORROSION OF LEAD SHIELDING IN NUCLEAR MATERIALS PACKAGES  

SciTech Connect

Inspection of United States-Department of Energy (US-DOE) model 9975 nuclear materials shipping package revealed corrosion of the lead shielding that was induced by off-gas constituents from organic components in the package. Experiments were performed to determine the corrosion rate of lead when exposed to off-gas or degradation products of these organic materials. The results showed that the room temperature vulcanizing (RTV) sealant was the most corrosive organic species used in the construction of the packaging, followed by polyvinyl acetate (PVAc) glue. Fiberboard material, also used in the construction of the packaging induced corrosion to a much lesser extent than the PVAc glue and RTV sealant, and only in the presence of condensed water. The results indicated faster corrosion at temperatures higher than ambient and with condensed water. In light of these corrosion mechanisms, the lead shielding was sheathed in a stainless steel liner to mitigate against corrosion.

Subramanian, K; Kerry Dunn, K; Joseph Murphy, J

2008-07-18

212

Macroporous poly(vinyl alcohol) microspheres bearing phosphate groups as a new adsorbent for low-density lipoprotein apheresis.  

PubMed

A new low-density lipoprotein (LDL) adsorbent with phosphate groups as the ligand was prepared in this study. Macroporous poly(vinyl acetate-co-triallyl isocyanurate) microspheres were prepared using a free-radical suspension polymerization method. A hydrolysis reaction in sodium hydroxide/methanol changed the materials into poly(vinyl alcohol) (PVA) microspheres. Further reaction with phosphorus oxychloride in anhydrous DMF led to the LDL adsorbent PVA-phosphate microspheres. The preparation conditions such as reaction time, temperature and the amount of phosphorus oxychloride were optimized. The adsorption of plasma lipoproteins was examined by in vitro adsorption assays. The influence of adsorption time, plasma volume and ionic strength on the adsorption capacity was investigated. The circulation adsorption showed that the pathogenic lipoproteins in the plasma such as total cholesterol (TC), LDL and triglyceride (TG) could be removed markedly, in which the removal percentages were 42.9%, 45.0% and 44.74%, respectively. However, the reduction of high-density lipoprotein (HDL) and other normal plasma components was very slight. For in vivo experiment, rabbits were fed with high-cholesterol food to develop a hyperlipidemia model and treated by extracorporeal blood perfusion using the PVA-phosphate columns. Eight hyperlipidemia rabbits were treated with the PVA-phosphate adsorbent, and the removal of TC, LDL and TG was 45.03 +/- 6.64%, 48.97 +/- 9.92% and 35.42 +/- 14.17%, respectively. The sterilization and storage tests showed that the adsorbent was chemically and functionally stable. It could be easily sterilized by a common method and stored for months without loss of adsorption capacity. Therefore, this new PVA-phosphate-based LDL adsorbent may have potential for application in LDL apheresis. PMID:19934485

Wang, Weichao; Xie, Hui; Sun, Lisha; Ou, Lailiang; Wang, Lianyong; Yu, Yaoting; Kong, Deling

2009-12-01

213

Investigation on isobaric vapor–liquid equilibrium for acetic acid + water + methyl ethyl ketone + isopropyl acetate  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium (VLE) data for acetic acid+water, acetic acid+methyl ethyl ketone (MEK), MEK+isopropyl acetate, acetic acid+MEK+water and acetic acid+MEK+isopropyl acetate+water are measured at 101.33kPa using a modified Rose cell. The nonideal behavior in vapor phase of binary systems measured in this work is analyzed through calculating fugacity coefficients since mixture containing acetic acid deviates from ideal behavior seriously in

Qiang Xie; Hui Wan; MingJuan Han; GuoFeng Guan

2009-01-01

214

Preparation and application of low molecular weight poly(vinyl chloride). III mechanical properties of blended poly(vinyl chloride)  

SciTech Connect

The blending effect of poly(vinyl chloride) with relatively higher molecular weight (HMW-PVC) and relatively lower molecular weight (LMW-PVC) has been investigated by measuring various mechanical properties: melt properties, tensile strength, tensile modulus, and impact strength. The blended PVC has slightly improved melt properties in comparison with the HMW-PVC used. The tensile strength of the blended PVC is related to the weight-average polymerization degree (Pw) of LMW-PVC and the LMW-PVC content. At the LMW-PVC content of 20%, the tensile strength of blended PVC is a maximum: approximately 58 MPa.

Yamamoto, Kikuo; Maehala, Takashi; Mitani, Katsuo; Mizutani, Yukio (Tokuyama Soda Co., Ltd., Tokuyama-city (Japan))

1993-11-05

215

Cross-linked polyvinyl alcohol and method of making same  

SciTech Connect

A film-forming polyvinyl alcohol polymer is mixed with a polyaldehyde-polysaccharide cross-linking agent having at least two monosaccharide units and a plurality of aldehyde groups per molecule, preferably an average of at least one aldehyde group per monosaccharide units. The cross-linking agent, such as a polydialdehyde starch, is used in an amount of about 2.5 to 20% of the theoretical amount required to cross-link all of the available hydroxyl groups of the polyvinyl alcohol polymer. Reaction between the polymer and cross-linking agent is effected in aqueous acidic solution to produce the cross-linked polymer. The polymer product has low electrical resistivity and other properties rendering it suitable for making separators for alkaline batteries. In that event, the mixture of polymer and cross-linking agent is formed into a sheet or film or the like and the film is cut to size and otherwise fabricated into a configuration suitable for a particular end use. The crosslinking reaction is then carried out to produce the final product.

Hsu, L.; Philipp, W.H.; Sheibley, D.W.

1981-06-09

216

Comparison of storage stability of odorous VOCs in polyester aluminum and polyvinyl fluoride Tedlar® bags.  

PubMed

Whole air sampling using containers such as flexible bags or rigid canisters is commonly used to collect samples of volatile organic compounds (VOC) in air. The objective of this study was to compare the stability of polyester aluminum (PEA) and polyvinyl fluoride (PVF, brand name Tedlar(®)) bags for gaseous VOC sampling. Eight VOC standards (benzene, toluene, p-xylene, styrene, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, and isobutyl alcohol) were placed into each bag at storage times of 0, 2, and 3 days prior to analyses by gas chromatography/mass spectrometry (GC/MS). From each bag representing each storage day, samples of 3 different mass loadings were withdrawn and analyzed to derive response factors (RF) of each chemical between the slope of the GC response (y-axis) vs. loaded mass (x-axis). The relative recoveries (RR) of VOC, if derived by dividing RF value of a given storage day by that of 0 day, varied by time, bag type, and VOC type. If the RR values after three days are compared, those of methyl isobutyl ketone were the highest with 96 (PVF) and 99% (PEA); however, the results of isobutyl alcohol were highly contrasting between the two bags with 31 and 94%, respectively. Differences in RR values between the two bag types increased with storage time, such that RR of PEA bags (88±10%) were superior to those of PVF bags (73±22%) after three days, demonstrating that VOC in PEA bags were more stable than in PVF bags. PMID:22177080

Kim, Yong-Hyun; Kim, Ki-Hyun; Jo, Sang-Hee; Jeon, Eui-Chan; Sohn, Jong Ryeul; Parker, David B

2011-11-15

217

The ?-effective paradox revisited: an extended analysis of Kovacs’ volume recovery data on poly(vinyl acetate)  

Microsoft Academic Search

In 1964 Kovacs (Kovacs, AJ, Transition vitreuse dans les polymères amorphes. Etude phénoménologique. Fortschr Hochpolym-Forsch 1964;3:394–507) published a paper in which he analyzed structural (volume) recovery data in asymmetry of approach experiments. Kovacs used a parameter referred to as ?-effective (?eff) which is defined in terms of the volume departure from equilibrium ? as ?eff?1=?1\\/?d?\\/dt. In plots of the log(1\\/?eff)

G. B. McKenna; M. G. Vangel; A. L. Rukhin; S. D. Leigh; B. Lotz; C. Straupe

1999-01-01

218

COMBUSTION PROPERTIES OF LAMINATED VENEER LUMBERS BONDED WITH POLYVINYL ACETATE AND PHENOL FORMALDEHYDE ADHESIVES AND IMPREGNATED WITH SOME CHEMICALS  

Microsoft Academic Search

The demand for engineering wood products (such as oriented strand board, glulam, and laminated veneer lumber [LVL]) has increased due to a constant increase in the global population. The processes of combustion are extremely complicated, principally because the wood has a complex physical and chemical composition. The burning of hydrocarbons is frequently chaotic. In this study, the effects of impregnation

BURHANETTIN UYSAL

2005-01-01

219

Application of active layering and coating techniques in the development of a multiparticulate, controlled release dosage form of a high-dose, highly soluble drug.  

PubMed

Abstract Context: The success of the development of controlled release, multilayered, multiparticulate dosage form of a high-dose, highly-soluble drug is dependent upon proper material and processing choices. Objective: To develop a controlled release dosage form of diltiazem hydrochloride using active layering and coating. Methods: Active layering was achieved by spraying a drug solution onto sugar cores using polyvinyl alcohol - polyethylene glycol as a binder. Layered pellets with highest loading and lowest binder content were coated using aqueous dispersions of polyvinyl acetate (PVAc). The effects of the plasticizer and curing on drug release were evaluated. Results and discussion: The binder level had no effect on the process efficiency. Drug release from PVAc-coated pellets was slowed by increasing PVAc level. Plasticization slowed drug release in comparison to nonplasticized formulations. Curing affected drug release of nonplasticized formulations only. Protection against humidity was essential in stabilizing drug release under stability study conditions. Conclusion: Materials and process used were suitable to face the challenge posed by the high dose of the water-soluble drug on the success of the formulation. The effects of the plasticizer, curing and ability of packaging to protect against elevated humidity on the performance of the studied system should be considered in development. PMID:23767814

Ahmad, Haitham; Khalifeh, Ismail; Alkhalidi, Bashar; Aiedeh, Khaled; Alkhatib, Hatim S

2013-06-14

220

Utilizing Matrix-Filler Interactions in the Design of Stimuli-Responsive, Mechanically-Adaptive Electrospun Composites  

NASA Astrophysics Data System (ADS)

A new class of all-organic, stimuli-responsive and mechanically-adaptive electrospun nanocomposites, which have the ability to alter their stiffness upon hydration, were developed. These materials were fabricated by incorporating an electrospun mat of poly(vinyl alcohol) (PVA) as the filler in a polymeric matrix consisting of either poly(vinyl acetate) (PVAc) or ethylene oxide-epicholorohydrin copolymer (EO-EPI). The incorporation of high stiffness, high aspect ratio PVA filler mat significantly enhanced the tensile storage modulus of EO-EPI based composites, while modulus enhancement was only noticed above the glass transition for PVAc-based composites. Composite materials based on a rubbery EO-EPI host polymer and PVA filler exhibit an irreversible reduction by a factor of 12 of the tensile modulus upon hydration. In contrast, composites comprised of PVAc show a reversible reduction of modulus by a factor of 280 upon water uptake. The mechanical morphing of the electrospun composites is the result of the filler crystallinity, and matrix-filler interactions facilitated by the surface hydroxyl groups of the PVA filler. The choice of polymer matrix and electrospun nanofiber fillers allow control of matrix-filler interactions in a new series of all-organic composites to achieve desired stimuli-responsiveness and mechanical-adaptability upon exposure to various stimuli.

Wanasekara, Nandula; Stone, David; Wnek, Gary; Korley, Lashanda

2013-03-01

221

New process for producing cellulose acetate from wood in concentrated acetic acid  

Microsoft Academic Search

To explore further potential applications of acetic acid pulp, an investigation was conducted to develop a direct method for producing cellulose acetate from wood in combination with atmospheric acetic acid pulping. The process consists of delignification, totally chlorine-free bleaching, and esterification, with the concentrated acetic acid aqueous solution being used as only solvent throughout the process. The acetic acid pulp

Hironori Sato; Yasumitsu Uraki; Takao Kishimoto; Yoshihiro Sano

2003-01-01

222

REMOVAL OF ACETIC ACID IMPURITIES FROM ETHYL ACETATE BY ADSORPTION ON ION EXCHANGE RESINS  

Microsoft Academic Search

Removal of acetic acid impurities from ethyl acetate was attempted by sorption on basic ion-exchange resins. Kinetic studies showed that acid removal is controlled by intraparticle resistance from both ethyl acetate and alcohol. Breakthrough curves for uptake of the acid from ethyl acetate were obtained at different flow rates and concentrations. Desorption studies were performed using both ethyl acetate and

H. M. Anasthas; V. G. Gaikar

2001-01-01

223

[Determination of organotin compounds in polyvinyl chloride toys].  

PubMed

Organotin compounds in polyvinyl chloride toys were determined by GC/MS after ethyl derivatization with sodium tetraethylborate. The samples were 12 balls, 12 soft toys, 10 food toys and 13 face masks for children. Monooctyltin, dioctyltin and trioctyltin compounds were found in all face masks at the levels of 74.8-917 micrograms/g. 474-3,960 micrograms/g and 1.0-213 micrograms/g, respectively. They also were detected in 6 balls, 4 soft toys and 1 food toy. Monomethyltin and dimethyltin compounds were found in 8 face masks at the levels of 40.9-227 micrograms/g and 222-1,450 micrograms/g, respectively. Monobutyltin and dibutyltin (DBT) compounds were found in 1 ball, 3 food toys and 5 face masks. In particular, 1 ball and 4 face masks contained toxic DBT at the levels of 527-999 micrograms/g. PMID:14606431

Ohno, Hiroyuki; Suzuki, Masako; Aoyama, Taiki; Mitani, Kazunori

2003-08-01

224

Friction loss in straight pipes of unplasticized polyvinyl chloride.  

PubMed

In order to design proper ductwork for a local exhaust system, airflow characteristics were investigated in straight pipes of unplasticized polyvinyl chloride (PVC). A linear decrease in static pressure was observed downstream at points from the opening of the VU pipes (JIS K 6741) located at distances greater than 10 times the pipe diameter, for velocities ranging between 10.18-36.91 m/s. Roughness inside pipes with small diameters was found to be 0.0042-0.0056 mm and the friction factor was calculated on the basis of Colebrook's equation for an airflow transition zone. An extended friction chart was then constructed on the basis of the roughness value and the friction factor. This chart can be applied when designing a local exhaust system with the ducts of diameters ranging from 40 to 900 mm. The friction loss of the PVC pipe was found to be approximately 2/3 of that of a galvanized steel pipe. PMID:8768669

Iwasaki, T; Ojima, J

1996-01-01

225

Vitrification of Polyvinyl Chloride Waste from Korean Nuclear Power Plants  

SciTech Connect

Vitrification is considered as an economical and safe treatment technology for low-level radioactive waste (LLW) generated from nuclear power plants (NPPs). Korea is in the process of preparing for its first ever vitrification plant to handle LLW from its NPPs. Polyvinyl chloride (PVC) has the largest volume of dry active wastes and is the main waste stream to treat. Glass formulation development for PVC waste is the focus of study. The minimum additive waste stabilization approach has been utilized in vitrification. It was found that glasses can incorporate a high content of PVC ash (up to 50 wt%), which results in a large volume reduction. A glass frit, KEP-A, was developed to vitrify PVC waste after the optimization of waste loading, melt viscosity, melting temperature, and chemical durability. The KEP-A could satisfactorily vitrify PVC with a waste loading of 30 to 50 wt%. The PVC-frit was tolerant of variations in waste composition.

Sheng, Jiawei [Kyoto University (Japan); Choi, Kwansik [Nuclear Environment Technology Institute (Korea, Republic of); Yang, Kyung-Hwa [Nuclear Environment Technology Institute (Korea, Republic of); Lee, Myung-Chan [Nuclear Environment Technology Institute (Korea, Republic of); Song, Myung-Jae [Nuclear Environment Technology Institute (Korea, Republic of)

2000-02-15

226

Alignment layers with variable anchoring strengths from Polyvinyl Alcohol  

NASA Astrophysics Data System (ADS)

In the study of polyvinyl alcohol (PVA) alignment layers for liquid crystal devices, we found that the anchoring strength can be greatly varied by changing the alignment film thickness. Both the polar and azimuthal anchoring strengths increased with increasing film thickness; however, they had different film thickness dependences. It was also noticed that the quartic term in the expansion of the Rapini-Papoular anchoring energy was important for describing the polar anchoring. In the experiment, solid PVA was dissolved in a thinner and spin-coated on glass substrates to create alignment layers. The substrates were assembled to make electrically-controlled birefringence liquid crystal cells. The polar anchoring strength of the alignment layer was measured using the high field method and the azimuthal anchoring strength using the twist angle method.

Cui, Yue; Zola, Rafael S.; Yang, Young-Cheol; Yang, Deng-Ke

2012-03-01

227

Cross-linked polyvinyl alcohol films as alkaline battery separators  

SciTech Connect

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

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

1982-03-01

228

Cross-linked polyvinyl alcohol films as alkaline battery separators  

SciTech Connect

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

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

1983-02-01

229

Polyvinyl alcohol coating of polystyrene inertial confinement fusion targets  

SciTech Connect

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

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

1985-05-01

230

[Applications of polyvinyl alcohol in modern preparations of TCM].  

PubMed

As a drug additive, polyvinyl alcohol(PVA) has merits of solubility, easy forming, strong conglutination, high thermal stability, low toxicity and no irritation. In these years, PVA has been applied wider and wider in medicine industry. In the study of modem preparations of TCM PVA, as film material of membrane and pellicles, is very promising owing to its easy forming and excellent toughness. PVA is good polymer matrix for suppositories and gel, because it can not only carry drug but also improve the properties of preparations on application and technology. It can be said that PVA is an excellent carrier. At the present, PVA is mainly applied in vitro preparations of TCM, but its applications will be spread with further research. The prospective applications of PVA in osmotic pump controlled release preparations, drug carried microspheres and swelling controlled release system are foreseen. PMID:15719670

Zhang, Yun-hui; Li, Ning; Xu, Jian-chen; Xiao, Li

2004-02-01

231

Estimation of mechanochemical dechlorination rate of poly(vinyl chlorde).  

PubMed

Poly(vinyl chloride) (PVC) was ground in air with CaO in the presence of quartz powder as a grinding aid by a small-scale planetary ball mill to investigate the relation of the dechlorination rate of PVC with the impact energy of the balls calculated from a computer simulation based on the Discrete Element Method under various conditions. Mechanochemical dechlorination proceeds as the grinding progresses and is improved with an increase in both the mill speed and the amount of balls introduced into the mill. The same trend can be seen in the relation between the specific normal impact energy of the balls and the rotational speed. The relationship between the observed dechlorination rate and the computed normal impact energy of the balls is linear, with a correlation coefficient of 0.965. This relationship can be used to estimate the dechlorination rate of PVC in a large-scale planetary ball mill. PMID:11944691

Mio, Hiroshi; Saeki, Shu; Kano, Junya; Saito, Fumio

2002-03-15

232

Dancing on coke: smuggling cocaine dispersed in polyvinyl alcohol.  

PubMed

Recent trends suggest that cocaine smugglers have become more and more inventive to avoid seizures of large amounts of cocaine transported between countries. We report a case of a mail parcel containing a dance pad which was seized at the Customs Department of Brussels Airport, Belgium. After investigation, the inside of the dance pad was found to contain a thick polymer, which tested positive for cocaine. Analysis was performed using a routine colorimetric swipe test, gas chromatography coupled with mass spectrometry and nuclear magnetic resonance spectroscopy. The polymer was identified as polyvinyl alcohol (PVA) and contained 18% cocaine, corresponding to a street value of € 20,000. Laboratory experiments showed that cocaine could be easily extracted from the PVA matrix. This case report reveals a new smuggling technique for the transportation of large amounts of cocaine from one country to another. PMID:22040352

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

2011-10-31

233

Polyvinyl chloride meat-wrapping film study. Final report  

SciTech Connect

As a result of worker complaints in the Baltimore, Maryland area, potential health hazards associated with the use of polyvinyl-chloride film for wrapping meat were reviewed. Fumes generated during the meat-wrapping process were causing concern among the workers as they experienced respiratory irritation and distress. It appeared that only some of the meat wrappers experienced difficulty, only some of the rolls of film-produced irritations in the affected workers, and affected workers had prior histories of respiratory difficulties. Fumes were generated during hot-wire film cutting. The amount of fume generated depended significantly on the care taken during the operation. If the dispensing machines were improperly adjusted, large amounts of fumes could be obtained during the cutting process. The author concludes that the amounts of these chemicals released during this operation does not constitute a health hazard to the employees. It may be necessary, however, to remove persons with prior respiratory irritation from this particular job location.

Vandervort, R.

1988-01-01

234

Spectroscopic manifestations of flavomononucleotide dimers in polyvinyl alcohol films.  

PubMed

Absorption and fluorescence spectra of flavomononucleotide (FMN) in polyvinyl alcohol films (PVA) over a very wide concentration range are investigated. The dimerization constant as well as the pure monomer and dimer spectra are calculated and the structural parameters of FMN dimer are established. Excitation wavelength and temperature dependencies of FMN/PVA fluorescence spectra for different FMN concentrations were carried out. These measurements together with those of absorption reveal that dimers are imperfect traps for excitation energy and that the energy transfer can occur both in forward and in reverse direction. Moreover, it was shown that the observed temperature changes in fluorescence spectra may be qualitatively explained by the effect of inhomogeneous broadening of FMN energy levels and by the presence of fluorescent dimers. PMID:9659386

Grajek, H; Zurkowska, G; Bojarski, P; Kukli?ski, B; Smyk, B; Drabent, R; Bojarski, C

1998-05-19

235

Growth characteristics of selected fungi on polyvinyl film  

SciTech Connect

The objective of this study was to determine if plasticized polyvinyl chloride film would support the growth of any of nine species of fungi. The film was suspended in distilled water with no nutrients or with glucose or ammonium sulfate. Spores of each of the test species were inoculated into the suspension medium, and the mixture was incubated at 30/sup 0/C for up to 18 weeks. Most species were found to be capable of utilizing the film for carbon or nitrogen when the other nutrient was supplied. Only two species, Aspergillus fischeri and Paecilomyces sp., were found to be capable of utilizing components of the film without added nutrients. Components of the polyvinyl chloride film were then incorporated into mineral salts medium to determine if these components could serve as carbon sources in the presence of ammonium nitrate. The only component found to be utilized by all the fungi as a carbon source was epoxidized oil, a plasticizer-stabilizer. Calcium-zinc stearate was an available carbon source for all except the Penicillium and Verticillium strains. The only other component utilized was a stearamide, which was metabolized solely by the Aspergillus sp. Only the stearamide contained enough nitrogen to serve as a primary source in the film. The compound, however, did not support growth of fungi in the presence of glucose. It was theorized that either the nitrogen of the stearamide was more readily available to the fungi in the whole film due to the presence of trace nutrients or the nitrogen was supplied by exogenous sources.

Roberts, W.T.; Davidson, P.M.

1986-04-01

236

Growth characteristics of selected fungi on polyvinyl chloride film.  

PubMed Central

The objective of this study was to determine if plasticized polyvinyl chloride film would support the growth of any of nine species of fungi. The film was suspended in distilled water with no nutrients or with glucose or ammonium sulfate. Spores of each of the test species were inoculated into the suspension medium, and the mixture was incubated at 30 degrees C for up to 18 weeks. Most species were found to be capable of utilizing the film for carbon or nitrogen when the other nutrient was supplied. Only two species, Aspergillus fischeri and Paecilomyces sp., were found to be capable of utilizing components of the film without added nutrients. Components of the polyvinyl chloride film were then incorporated into mineral salts medium to determine if these components could serve as carbon sources in the presence of ammonium nitrate. The only component found to be utilized by all the fungi as a carbon source was epoxidized oil, a plasticizer-stabilizer. Calcium-zinc stearate was an available carbon source for all except the Penicillium and Verticillium strains. The only other component utilized was a stearamide, which was metabolized solely by the Aspergillus sp. Only the stearamide contained enough nitrogen to serve as a primary source in the film. The compound, however, did not support growth of fungi in the presence of glucose. It was theorized that either the nitrogen of the stearamide was more readily available to the fungi in the whole film due to the presence of trace nutrients or the nitrogen was supplied by exogenous sources.

Roberts, W T; Davidson, P M

1986-01-01

237

77 FR 22847 - National Emission Standards for Hazardous Air Pollutants for Polyvinyl Chloride and Copolymers...  

Federal Register 2010, 2011, 2012, 2013

...distinct enough from polyvinyl chloride polymers that the EPA used the conjunctive...chloride copolymer is a highly crystalline polymer, making the removal or stripping of...resin more difficult than typical PVC polymers. The commenter stated that, to...

2012-04-17

238

Fluorine Magnetic Resonance Spectra and Tacticities of Poly(Vinyl Trifluoroacetate).  

National Technical Information Service (NTIS)

Fluorine magnetic resonance spectra of poly(vinyl trifluoroacetate) samples of different tacticities were investigated, along with those of model compounds. These polymers represent the first case where the line order in respect to stereostructure does no...

K. Fujii S. Brownstein A. M. Eastham

1968-01-01

239

Spectroscopic investigation of the thermal conversion of catalytically dehydrated polyvinyl alcohol  

SciTech Connect

The authors examine the structural conversion of dehydrated polyvinyl alcohol thermally treated at temperatures exceeding the temperature of the catalytic dehydration. The authors used electron and infrared spectroscopy to study the thermal conversion of catalytically dehydrated polyvinyl alcohol in an inert atmosphere and in air. Aluminum chloride and hydrogen chloride were used as catalysts of the dehydration. Spectra are shown which were obtained in the visible part from ALCL/sub 3/-containing polyvinyl alcohol films after their thermal treatment in an inert gas flow. It is shown that optimal temperatures must be selected to obtain high-quality recordings of optical information when the dehydration of polyvinyl alcohol is to be used to advantage.

Gavrilov, M.Z.

1986-09-01

240

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

Code of Federal Regulations, 2010 CFR

...Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants. 61.65 Section 61.65 Protection...POLLUTANTS National Emission Standard for Vinyl Chloride § 61.65 Emission standard for ethylene...

2009-07-01

241

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

Code of Federal Regulations, 2010 CFR

...Emission standard for ethylene dichloride, vinyl chloride and polyvinyl chloride plants. 61.65 Section 61.65 Protection...POLLUTANTS National Emission Standard for Vinyl Chloride § 61.65 Emission standard for ethylene...

2010-07-01

242

Fluorescent nano particles in the aqueous phase by polymer analogous reaction of polyvinyl alcohol  

NASA Astrophysics Data System (ADS)

Polyvinyl alcohol (PVA) was condensed with perylene aldehydes to form functional nano particles. These are self-dispersing in the aqueous phase and form strongly fluorescent media with large Stokes' shifts caused by the interaction of chromophores. Applications are discussed.

Langhals, Heinz; Pust, Tim

2010-10-01

243

Biofiltration of ethyl acetate and amyl acetate using a composite bead biofilter.  

PubMed

Biodegradation kinetic behaviors of ethyl acetate and amyl acetate in a composite bead biofilter were investigated. The composite bead was the spherical PVA/peat/KNO3/GAC composite bead which was prepared in our previous works. Both microbial growth rate and biochemical reaction rate were inhibited at higher inlet concentration. For the microbial growth process, the microbial growth rate of ethyl acetate was greater than that of amyl acetate in the inlet concentration range of 100-400ppm. The degree of inhibitive effect was almost the same for ethyl acetate and amyl acetate in this concentration range. The half-saturation constant Ks values of ethyl acetate and amyl acetate were 16.26 and 12.65ppm, respectively. The maximum reaction rate Vm values of ethyl acetate and amyl acetate were 4.08 and 3.53gCh(-1)kg(-1) packed material, respectively. Zero-order kinetic with the diffusion limitation could be regarded as the most adequate biochemical reaction model. For the biochemical reaction process, the biochemical reaction rate of ethyl acetate was greater than that of amyl acetate in the inlet concentration range of 100-400ppm. The inhibitive effect for ethyl acetate was more pronounced than that for AA in this concentration range. The maximum elimination capacity of ethyl acetate and amyl acetate were 82.3 and 37.93gCh(-1)m(-3) bed volume, respectively. Ethyl acetate degraded by microbial was easier than amyl acetate did. PMID:18445522

Chan, Wu-Chung; Su, Mei-Qi

2008-04-28

244

MINIRIN Desmopressin acetate 1. EXECUTIVE SUMMARY ..... ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... Brand Name MINIRIN Generic Name Desmopressin acetate ... NDA 21795 MINIRIN (desmopressin acetate) 0.1 mg and 0.2 mg Tablets Page 1 of 30 ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

245

Poly(vinyl chloride) (PVC) hollow fiber ultrafiltration membranes prepared from PVC\\/additives\\/solvent  

Microsoft Academic Search

Using poly(vinyl pyrrolidone) (PVP 40,000) or poly(ethylene glycol) (PEG) with different molecular weights (PEG 600, PEG 800, PEG 1000) as additives and N,N-dimethylacetamide (DMAc) as a solvent, asymmetric poly(vinyl chloride) (PVC) hollow fiber ultrafiltration membranes were prepared by phase inversion technique from 14 to 20wt.% solids including PVC and additives. The 95\\/5 DMAc\\/water and pure water were used as the

Jian Xu; Zhen-Liang Xu

2002-01-01

246

Organically crosslinked polyvinyl alcohol copolymetric gels for use under harsh reservoir conditions  

SciTech Connect

This patent describes a process for recovering oil from a subterranean oil-bearing formation having relatively high permeability zones and relatively low permeability zones penetrated by at least one production well in fluid communication with a substantial portion of the formation. It comprises: injecting into the formation an aqueous gel-forming composition comprising water, a water-dispersible polyvinyl alcohol copolymer, the polyvinyl alcohol copolymer selected from the group consisting of copolymers of vinyl alcohol and vinyl alkyl sulfonate either.

Haskin, D.H.; Shu, P.

1990-07-10

247

Hybrid material polyvinyl alcohol-copper oxide and its electrical properties  

NASA Astrophysics Data System (ADS)

The hybrid material polyvinyl alcohol-copper oxide was produced by the thermal decomposition of polyvinyl alcohol-copper hydroxide complex compound. It was analyzed by means of XRD, UV-VIS, IR, and Raman spectroscopy. It was concluded that the most part of copper oxide has an amorphous structure and consists of -(Cu-O) n - chains. The electrical properties of this material were investigated at direct and alternating current in 80-375 K temperature range.

Prosanov, I. Yu.; Bulina, N. V.; Chesalov, Yu. A.

2012-08-01

248

Preparation and characterization of processable electroactive polyaniline–polyvinyl alcohol composite  

Microsoft Academic Search

In this paper, the preparation and characterization of polyaniline–polyvinyl alcohol composites is described. The polyaniline composite was synthesized by chemical polymerization of aniline in media containing polyvinyl alcohol (10%, w\\/w). Oxidation of aniline results in a stable water based polyaniline dispersion, which can be cast to form a mechanically robust film.The electrical conductivity of the films increased with increasing amount

A Mirmohseni; G. G Wallace

2003-01-01

249

Radiation-chemical synthesis of poly(vinyl alcohol) hydrogel containing dicyclohexano-18-crown-6  

Microsoft Academic Search

Radiation-chemical synthesis of poly(vinyl alcohol) hydrogels containing physically immobilized dicyclohexano-18-crown-6 was carried out. Remarkable gel fraction of 40–70% was observed at absorbed dose of about 5kGy. Increasing degree of poly(vinyl alcohol) crosslinking led to growth of the efficiency of crown ether immobilization. Post-irradiation thermal annealing of the hydrogel samples at 120°C for 0.5–5h resulted in an increase of crown ether

O. A. Zakurdaeva; S. V. Nesterov; N. A. Shmakova; G. K. Semenova; E. O. Sozontova; V. I. Feldman

2007-01-01

250

Radiation-chemical synthesis of poly(vinyl alcohol) hydrogel containing dicyclohexano-18-crown-6  

Microsoft Academic Search

Radiation-chemical synthesis of poly(vinyl alcohol) hydrogels containing physically immobilized dicyclohexano-18-crown-6 was carried out. Remarkable gel fraction of 40 70% was observed at absorbed dose of about 5 kGy. Increasing degree of poly(vinyl alcohol) crosslinking led to growth of the efficiency of crown ether immobilization. Post-irradiation thermal annealing of the hydrogel samples at 120 °C for 0.5 5 h resulted in

O. A. Zakurdaeva; S. V. Nesterov; N. A. Shmakova; G. K. Semenova; E. O. Sozontova; V. I. Feldman

2007-01-01

251

21 CFR 73.2396 - Lead acetate.  

Code of Federal Regulations, 2013 CFR

...ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2396 Lead acetate. (a...additive lead acetate may be safely used in cosmetics intended for coloring hair on the scalp...The amount of the lead acetate in the cosmetic shall be such that the lead...

2013-04-01

252

27 CFR 21.107 - Ethyl acetate.  

Code of Federal Regulations, 2013 CFR

...107 Ethyl acetate. (a) 85 percent ester: (1) Acidity (as acetic acid). Not more than 0.015 percent by weight...and none above 80 °C. (b) 100 percent ester: (1) Acidity (as acetic acid). Not more than 0.010 percent by...

2013-04-01

253

Kinetics of the Methanogenic Fermentation of Acetate  

PubMed Central

Inhibition of the fermentation of acetate to methane and carbon dioxide by acetate was analyzed with an acetate-acclimatized sludge and with Methanosarcina barkeri Fusaro under mesophilic conditions. A second-order substrate inhibition model, qch4 = qmS/[Ks + S + (S2/Ki)], where S was the concentration of undissociated acetic acid, not ionized acetic acid, could be applicable in both cases. The analysis resulted in substrate saturation constants, Ks, of 4.0 ?M for the acclimatized sludge and 104 ?M for M. barkeri. The threshold concentrations of undissociated acetic acid when no further acetate utilization was observed were 0.078 ?M (pH 7.50) for the acclimatized sludge and 4.43 ?M (pH 7.45) for M. barkeri. These kinetic results suggested that the concentration of undissociated acetic acid became a key factor governing the actual threshold acetate concentration for acetate utilization and that the acclimatized sludge in which Methanothrix spp. appeared dominant could utilize acetate better and survive at a lower concentration of undissociated acetic acid than could M. barkeri. Images

Fukuzaki, Satoshi; Nishio, Naomichi; Nagai, Shiro

1990-01-01

254

Polyvinyl alcohol functionalized cobalt ferrite nanoparticles for biomedical applications  

NASA Astrophysics Data System (ADS)

In the present work, cobalt ferrite nanoparticles (CoFe2O4 NPs) have been synthesized by combustion method. The surface of the CoFe2O4 NPs was modified with biocompatible polyvinyl alcohol (PVA). To investigate effect and nature of coating on the surface of CoFe2O4 NPs, the NPs were characterized X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The transmission electron microscopy (TEM) and dynamic light scattering (DLS) results demonstrate the monodispersed characteristics of CoFe2O4 NPs after surface modification with PVA. The decrease in contact angle from 162° to 50° with PVA coating on NPs indicates the transition from hydrophobic nature to hydrophilic. The Magnetic properties measurement system (MPMS) results show that the NPs have ferromagnetic behavior with high magnetization of 75.04 and 71.02 emu/g of uncoated and coated CoFe2O4 NPs respectively. These PVA coated NPs exhibit less toxicity over uncoated CoFe2O4 NPs up to 1.8 mg mL-1 when tested with mouse fibroblast L929 cell line.

Salunkhe, A. B.; Khot, V. M.; Thorat, N. D.; Phadatare, M. R.; Sathish, C. I.; Dhawale, D. S.; Pawar, S. H.

2013-01-01

255

Vinyl acetate formation in the reaction of acetylene with acetic acid catalyzed by zinc acetate supported on porous carbon spheres  

NASA Astrophysics Data System (ADS)

A kind of porous carbon spheres (PCS) was prepared by the carbonization of poly(vinylidene chloride) synthesized by suspension polymerization. Structure analyses revealed the existence of bumps and holes on the surface of PCS. The PCS, with the pore size between 0.8-1.2 nm, could be used as the support of zinc acetate because of the regular shape, high specific surface area, and good mechanical strength. Vinyl acetate was produced from acetylene and acetic acid using the PCS-supported zinc acetate (PCS-Zn) under mild conditions. In a single-pass operation performed at 220°C, the conversions of acetic acid and acetylene reached 22.6 and 5.3% respectively while the activity of vinyl acetate formation was above 1000 g mol-1 h-1.

Yan, Feng-Wen; Guo, Cun-Yue; Yan, Fang; Li, Feng-Bo; Qian, Qing-Li; Yuan, Guo-Qing

2010-05-01

256

New holographic polymeric composition based on plexiglass, polyvinyl butyral, and phenanthrenquinone  

NASA Astrophysics Data System (ADS)

The newly developed Plexiglas films containing polyvinyl butyral resins and phenanthrenequinone molecules as photosensitive dopant, which are proposed for the practical application as interlayer of laminated safety glass, are shown for the first time. The injection of the phenanthrenequinone-poly(methyl methacrylate) into the polyvinyl butyral protective interlayer provides a homogenous distribution of the recording holographic medium in the layer and allows fixing the entire surface grating in the laminated glass. In addition, the original properties of polyvinyl butyral as a connecting material were preserved during manufacturing of the laminated glass. This allows a recording of holographic structures directly after baking of the laminated glass, thus reducing the destruction of the gratings due to the elevated temperatures. The diffractive structures in phenanthrenequinone-poly(methyl methacrylate)-polyvinyl butyral polymeric layers with thicknesses of hundreds of microns are sealed between two panels of glass (so-called laminated glass) and are generated by illumination with an Argon-laser of 514 nm. Efficiently fixed and long-term stable holographic gratings recorded in the phenanthrenequinone-poly(methyl methacrylate)-polyvinyl butyral layer enable to produce transparent laminated glass with inserted diffractive elements, which can be used e.g. for Head-up Displays in automobile windshields or as holographic light concentrators for solar cells.

Matusevich, Vladislav; Tolstik, Elen; Kowarschik, Richard; Egorova, Elena; Matusevich, Yuri I.; Krul, Leonid

2013-05-01

257

Desmopressin Acetate (marketed as DDAVP Nasal Spray ...  

Center for Drug Evaluation (CDER)

... Desmopressin Acetate (marketed as DDAVP Nasal Spray, DDAVP Rhinal Tube, DDAVP, DDVP, Minirin, and Stimate Nasal Spray). ... More results from www.fda.gov/drugs/drugsafety/postmarketdrugsafetyinformationforpatientsandproviders

258

5?-Dihydro-vespertilin acetate  

PubMed Central

In the title compound, C24H36O4 [systematic name: (20S)-3?-acet­oxy-16?-hydr­oxy-22,23-bis­nor-5?,17?-cholano(22-16)lac­tone], the three six-membered rings adopt classical chair conformations, while the five-membered rings are in envelope conformations. The ester group attached to ring A is in an equatorial position. Rings A/B, B/C and C/D are trans-fused, whereas rings D/E are cis-fused. The structure is devoid of any classical hydrogen bonds. However, non-classical inter- and intra­molecular hydrogen-bonding inter­actions of the type C—H?O are present in the structure.

Benn, Michael; Vohra, Kanwal Nain; Parvez, Masood

2010-01-01

259

Preparation and characterization of polyvinyl alcohol—chitosan biocompatible magnetic microparticles  

NASA Astrophysics Data System (ADS)

This work addresses the obtaining of biocompatible magnetic polyvinyl alcohol—chitosan microspheres, specifically tailored/functionalised to bind directly blood toxins using an emulsion crosslinking preparation method. The following synthesis parameters were studied: water to oil phase ratio, polyvinyl alcohol molecular weight, chitosan to polyvinyl alcohol weight ratio, surfactant composition and concentration of the crosslinking agent. These parameters were optimized for producing a high yield of colloidally stable and uniformly sized particles with significant magnetization of saturation, bearing surface amino groups that can be further used to bind blood toxins directly. The particles were characterized regarding their size distribution and surface charge (laser diffraction analysis), morphology (transmission electron microscopy), magnetic properties, chemical composition (Fourier transform infrared spectroscopy) and concentration of the surface amino groups (conductometric titration).

Elena Udrea, Laura; Hritcu, Doina; Popa, Marcel Ionel; Rotariu, Ovidiu

2011-01-01

260

Indirect inhibition of polymerization of a polyvinyl siloxane impression material: a case report.  

PubMed

The inhibition of polymerization of polyvinyl siloxane impression materials by direct contact with latex gloves has been well documented. Indirect intraoral inhibition of polymerization that results from contact of oral tissues with latex gloves during tooth preparation and gingival retraction procedures has been reported. This case report illustrates the problems that can occur when the dentist used polyvinyl siloxane impression materials while wearing latex gloves. In the reported case, the inhibition is severe and obvious; in most situations the inhibition of polymerization is more subtle and is frequently undetected. Clinicians must be aware of this potential problem and the solution to it. PMID:2068247

Chee, W W; Donovan, T E; Kahn, R L

1991-02-01

261

Preparation and swelling behavior of physically crosslinked hydrogels composed of poly(vinyl alcohol) and chitosan  

Microsoft Academic Search

The physically crosslinked poly(vinyl alcohol)\\/chitosan (CS) composite hydrogels were prepared by cyclic freezing\\/thawing\\u000a techniques, and the microstructure and swelling behavior of the hydrogels in the simulated gastric (pH 1.0) and intestinal\\u000a (pH 7.4) media were investigated. The experimental results of infrared spectra (IR), scanning electron microscope (SEM) and\\u000a differential scanning calorimetry (DSC) demonstrated that poly(vinyl alcohol) and chitosan had good

Guanghua He; Hua Zheng; Fuliang Xiong

2008-01-01

262

Radical formation induced by ? radiation in poly(vinyl chloride) powder  

NASA Astrophysics Data System (ADS)

Poly(vinyl chloride) powders were submitted to ? irradiation in the dose range 25-150 kGy in vacuum, argon and air atmosphere conditions. The free radicals induced by radiation were investigated by EPR measurements performed at different times from the end of irradiation. Obtained results confirmed that at room temperature the poly(vinyl chloride) degradation process causes the formation of polyenil radicals, which can react with the oxygen diffused into the polymer giving rise to peroxyl radical species. The ratio of polyenil and peroxyl radicals is a function of the experimental condition atmosphere.

Costa, L.; Brunella, V.; Paganini, M. C.; Baccaro, S.; Cecilia, A.

2004-02-01

263

Hybrid reactive distillation systems for n-butyl acetate production from dilute acetic acid  

Microsoft Academic Search

The recovery of dilute acetic acid, regarding as a waste stream in many chemical and petrochemical processes, becomes an important issue due to economic and environmental awareness. In this work, a simulation study on the direct utilization of dilute acetic acid to produce n-butyl acetate via esterification with butanol in a reactive distillation is presented by using Aspen Plus. The

Amornchai Arpornwichanop; Kittipong Koomsup; Suttichai Assabumrungrat

2008-01-01

264

Ene diiodo acetals : stereoselective synthesis of ene hydroxy acetals. Handy access to non conjugated dienals  

Microsoft Academic Search

After halogen-metal exchange reaction followed by condensation with carbonyl compounds, ene diiodo acetal 1 allow the stereoselective synthesis of ene hydroxy acetals 2 with Z configuration, in a two step procedure. Moreover, after dehydration, the intermediate diene acetals 3–4, via an appropriated hydrolysis procedure, lead to pure non conjugated dienals 5.

B Bonnet; G Ple; L Duhamel

1998-01-01

265

Effect of Silica Nanoparticles on Compressive Strength of Leaves-Waste Composite  

NASA Astrophysics Data System (ADS)

The utilization of solid-waste, especially leaves-waste is one of interesting research of environmental field. One of them is making a composite using polyvinyl acetate (PVAc) polymer as binder (matrix) and silica nanoparticles as reinforcement (filler) to improve the strength of composite-produced. Those raw materials preliminary were mixed by simple mixing with varied compositions and then hot-pressed at 36 MPa and 100 °C for 20 minutes. From compressive strength test, it was found that composite with composition 7:8 of PVAc and leaves-waste had maximum compressive strength, i.e. 57.60 MPa. It was also that the enhancement of strength due to PVAc fraction (w/w) increasing is a percolation behavior, even though its mathematical explanation has not been performed. Into composition of maximum strength above, silica with average size is 74 nm then was added to improve the strength and found that at silica weight fraction of 0.79 (%w/w), the composite had optimum compressive strength, i.e. 70.5 MPa, or increased up to 22.4% of that without silica. The final compressive strength was very comparable to some building goods such as sandstones and bricks. The composite density was also measured and obtained that it was about 0.9 g/cm3 that is very close to some usual woods.

Masturi, Masturi; Aliah, Hasniah; Aji, Mahardika Prasetya; Sagita, Adi Ardian; Bukit, Minsyahril; Sustini, Euis; Khairurrijal, Khairurrijal; Abdullah, Mikrajuddin

2011-12-01

266

CORROSION OF LEAD SHIELDING IN MODEL 9975 PACKAGE  

SciTech Connect

Experiments were performed to determine the corrosion rate of lead when exposed to off-gas or degradation products of organic materials used in the model 9975 package.[1] The experiments were completed within the framework of a parametric test matrix with variables of organic configuration, temperature, humidity and the effect of durations of exposure on the corrosion of lead in the 9975 package. The room temperature vulcanizing (RTV) sealant was the most corrosive organic species in the testing, followed by the polyvinyl acetate (PVAc) glue. The Celotex{copyright} material uniquely induced measurable corrosion only in situations with condensed water, and to a much lesser extent than the PVAc glue and RTV. The coupons exhibited faster corrosion at higher temperatures than at room temperatures. There was a particularly pronounced effect of condensed water as the coupons exposed in the cells with condensed water exhibited much higher corrosion rates. In the 9975 package, the PVAc glue was determined to be the most aggressive due to it's proximity in the design. The condition considered most representative of the package conditions is that of the coupon exposed to the Celotex{copyright}/glue organic exposed in the ambient humidity conditions. The corrosion rate of 2 mpy measured in the laboratory experiments for this condition is considered to be a bounding condition to the 9975 package conditions when the laboratory results are extrapolated to actual package conditions, and is recommended as a conservative estimate for package performance calculations.

Subramanian, K

2006-03-15

267

Polymer-grafted silica: A screening system for polymeric adsorption resin development  

SciTech Connect

A screening-level methodology was developed for the evaluation of solute affinity for polymers that are candidate sorption resins. In this approach novel grafted polymer-silica resins were synthesized to produce poly(vinylpyrrolidone)-silica (PVP-Si) and poly(vinyl acetate)-silica (PVAc-Si) resins. The polymer-silica resins along with a number of commercially available polymer resins were used to evaluate the aqueous-phase adsorption of phenol, tetrachloroethene (PCE), trichloroethene (TCE), and chloroform. The polymer-grafted silicas were able to selectively remove pollutants from water with a covalently bonded polymer layer that has a high affinity for the target pollutant. The PVAc-silica resin had a sorption capacity for TCE and CHCl[sub 3] as high as commercial poly(styrene) resin XAD-4; the PVP-Si resin had a sorption capacity for phenol higher than a commercial poly-(vinylpyridine) resin (Reillex 425). PCE adsorption onto the PVAc-silica was comparable to the commercial poly(methacrylate) and poly(vinylpyridine) resins but less than the poly(styrene) resin. The results show that the Hildebrand solubility parameter along with the dipole moment of the polymer functional groups can be used for an initial screening-level assessment of polymer-solute affinity.

Browne, T.E.; Cohen, Y. (Univ. of California, Los Angeles (United States))

1993-04-01

268

Nanostructural surface engineering of grafted polymers on inorganic oxide substrates for membrane separations  

NASA Astrophysics Data System (ADS)

Nanostructural engineering of inorganic substrates by free radical graft polymerization was studied with the goal of developing new membrane materials for pervaporation. Graft polymerization consisted of modification of surface hydroxyls with vinyl trimethoxysilane, followed by solution graft polymerization reaction using either vinyl acetate (VAc) or vinyl pyrrolidone (VP). The topology of the modified surfaces was studied by atomic force microscopy (AFM) on both atomically smooth silicon wafer substrates and microporous inorganic membrane supports in order to deduce the effects of modification on the nanostructural properties of the membrane. While unmodified wafers showed a root-mean-square (RMS) surface roughness of 0.21 +/- 0.03 nm, roughness increased to 3.15 +/- 0.23 nm upon silylation. Under poor solvent conditions (i.e., air), surfaces modified with higher poly(vinyl acetate) (PVAc) or poly(vinyl pyrrolidone) (PVP) polymer graft yields displayed lateral inhomogeneities in the polymer layer. Although RMS surface roughness was nearly identical (0.81--0.85 nm) for PVAc-modified surfaces grafted at different monomer concentrations, the skewness of the height distribution decreased from 2.22 to 0.78 as polymer graft yield increased from 0.8 to 3.5 mg/m2. The polymer-modified surfaces were used to create inorganic pervaporation membranes consisting of a single macromolecular separation layer formed by graft polymerization. PVAc grafted silica membranes (500A native pore size) were found selective for MTBE in the separation of 0.1--1% (v/v) MTBE from water, achieving MTBE enrichment factors as high as 371 at a permeate flux of 0.38 l/m2 hr and a Reynolds number of 6390; however, these membranes could not separate anhydrous organic mixtures. Pervaporative separation of methanol/MTBE mixtures was possible with PVAc and PVP-modified alumina supports of 50A native pore size, where the separation layer consisted of grafted polymer chains with estimated radius of gyration 4.5--6.8 times larger than the membrane pore radius. Methanol separation factors for the PVP and PVAc-grafted alumina pervaporation membranes reached values of 26 and 100 (respectively) at total permeate fluxes of 0.055--1.26 kg/m 2 hr and 0.55--6.19 kg/m2 hr. The present study demonstrated that selective pervaporation membranes for separation of both organic/organic and organic/aqueous mixtures can be effectively designed by careful selection of the surface-grafted polymer chain density and the ratio of the polymer chain size to the native support pore size.

Yoshida, Wayne Hiroshi

269

Cross-Linked Poly(Ester-Acetals).  

National Technical Information Service (NTIS)

The cross-linked products have utility as bonding agents for glass laminates. Certain novel soluble poly(ester-acetal) resins initially formed under alkaline conditions, under which the acetal groups appear to be inactive, may be crossed-linked by the add...

E. H. Pryde

1965-01-01

270

Fermentation characteristics of Fusariumoxysporum grown on acetate.  

PubMed

In this study, the growth characteristics of Fusariumoxysporum were evaluated in minimal medium using acetate or different mixtures of acetate and glucose as carbon source. The minimum inhibitory concentration (MIC) of acetic acid that F.oxysporum cells could tolerate was 0.8%w/v while glucose was consumed preferentially to acetate. The activity of isocitrate lyase was high when cells were grown on acetate and acetate plus glucose indicating an activation of the glyoxylate cycle. Investigation of the metabolic fingerprinting and footprinting revealed higher levels of intracellular and extracellular TCA cycle intermediates when F.oxysporum cells were grown on mixtures of acetate and glucose compared to growth on only glucose. Our data support the hypothesis that a higher flux through TCA cycle during acetate consumption could significantly increase the pool of NADH, resulting in the activation of succinate-propionate pathway which consumes reducing power (NADH) via conversion of succinate to propionyl-CoA and produce propionate. PMID:18304808

Panagiotou, Gianni; Pachidou, Fotini; Petroutsos, Dimitris; Olsson, Lisbeth; Christakopoulos, Paul

2008-03-04

271

Physicochemical characterization and antibacterial property of chitosan acetates  

Microsoft Academic Search

In a new approach to the preparation of solid chitosan acetate, the dependence of solubility of chitsoan acetate on the mole ratio of acetic acid to GlcN residues of chitosan was evaluated from turbidity. The structure of the product chitosan acetate was characterized by titration and FT-IR. It was demonstrated that the chitosan acetate with high solubility retained the structure

Yan Li; Xi Guang Chen; Nan Liu; Cheng Sheng Liu; Chen Guang Liu; Xiang Hong Meng; Le Jun Yu; John F. Kenendy

2007-01-01

272

Organic/inorganic nanocomposites, methods of making, and uses as a permeable reactive barrier  

DOEpatents

Nanocomposite materials having a composition including an inorganic constituent, a preformed organic polymer constituent, and a metal ion sequestration constituent are disclosed. The nanocomposites are characterized by being single phase, substantially homogeneous materials wherein the preformed polymer constituent and the inorganic constituent form an interpenetrating network with each other. The inorganic constituent may be an inorganic oxide, such as silicon dioxide, formed by the in situ catalyzed condensation of an inorganic precursor in the presence of the solvated polymer and metal ion sequestration constituent. The polymer constituent may be any hydrophilic polymer capable of forming a type I nanocomposite such as, polyacrylonitrile (PAN), polyethyleneoxide (PEO), polyethylene glycol (PEG), polyvinyl acetate (PVAc), polyvinyl alcohol (PVA), and combinations thereof. Nanocomposite materials of the present invention may be used as permeable reactive barriers (PRBs) to remediate contaminated groundwater. Methods for making nanocomposite materials, PRB systems, and methods of treating groundwater are also disclosed.

Harrup, Mason K. (Idaho Falls, ID); Stewart, Frederick F. (Idaho Falls, ID)

2007-05-15

273

Desvenlafaxinium chloranilate ethyl acetate solvate  

PubMed Central

In the cation of the title compound, C16H26NO2 +·C6HCl2O4 ?·C4H8O2, the 1-hy­droxy-cyclo­hexyl ring adopts a slightly distorted chair conformation. The dihedral angle between the mean planes of the 1-hy­droxy­cyclo­hexyl and 4-hy­droxy­phenyl rings is 84.0?(8)°. In the anion, the hydroxyl H atom is twisted slightly out of the ring plane with a C—C—O—H torsion angle of ?171.9°. Disorder was modeled for the methyl group of the acetate group in the solvate with an occupancy ratio of 0.583?(15): 0.417?(15). In the crystal, O—H?O hydrogen bonds are observed between cations and between cations and anions, while bifuricated N—H?(O,O) cation–anion hydrogen bonds are also present, forming chains along [010] and [100]. In addition weak cation–anion and cation–solvate C—H?O inter­actions occur.

Kaur, Manpreet; Jasinski, Jerry P.; Butcher, Ray J.; Yathirajan, H. S.; Byrappa, K.

2013-01-01

274

Effect of surface modifications of leather on its joint strength with polyvinyl chloride  

Microsoft Academic Search

The treatment of bovine leathers with wetting and lyotropic agents followed by heating produced a strengthening of the leathers which increased their joint strength properties to polyvinyl chloride (PVC). A cohesive failure of leather was always obtained. The highest cohesive strength (or point peel strength) was obtained when the treatment was carried out at 140°C with the surfactant NFOE (8.5)

T. P. Ferrándiz-Gómez; M. Almela; J. M. Martín-Martínez; F. Maldonado; A. C. Orgilés-Barceló

1994-01-01

275

Synthesis and characterisation of hydrogels based on poly(vinyl pyrrolidone)  

Microsoft Academic Search

Poly(vinyl pyrrolidone) (PVP) hydrogels were crosslinked by using gamma irradiation technique. The effects of the PVP concentration and the absorbed dose on gel content were investigated. Equilibrium swelling study was performed to calculate molecular weight between crosslinks of swollen gel using Flory Rhenner theory. The oxygen effect was studied through the yield of crosslinking Gx which was deducted from the

S. Benamer; M. Mahlous; A. Boukrif; B. Mansouri; S. Larbi Youcef

2006-01-01

276

Assessment of Polyvinyl Chloride as a Packaging Material for Distilled Spirits.  

National Technical Information Service (NTIS)

The analysis is confined to the evaluation of the insults to our environment from using either polyvinyl chloride (PVC) or glass as a liquor container. The authors presents three discussions. The first is to provide a total assessment of the environmental...

R. C. Bailie B. T. Riley R. Zaltzman

1973-01-01

277

Preparation and characterization of polyvinyl alcohol hydrogels crosslinked by biodegradable polyurethane for tissue engineering of cartilage  

Microsoft Academic Search

Polyurethane was prepared from hexamethylene diisocyanate (HMDI) and polycaprolactone diol (PCL) with stoichiometry ratio of two in a reactor to form prepolymer. Polyvinyl alcohol (PVA) at PVA\\/prepolymer ratios of 8, 4, 2 and 1 was crosslinked with the former degradable polyester polyurethane. Fourier transform infrared (FTIR) was employed to confirm polyurethane formation during the course of reactions. FTIR spectrum revealed

Shahin Bonakdar; Shahriar Hojjati Emami; Mohammad Ali Shokrgozar; Afshin Farhadi; Seyed Amir Hoshiar Ahmadi; Amir Amanzadeh

2010-01-01

278

Recovery of agricultural odors and odorous compounds from polyvinyl fluoride film bags  

Technology Transfer Automated Retrieval System (TEKTRAN)

Accurate sampling methods are necessary when quantifying odor and volatile organic compound emissions at agricultural facilities. The commonly accepted methodology in the U.S. has been to collect odor samples in polyvinyl fluoride bags (PVF, brand name Tedlar®) and, subsequently, analyze with human ...

279

Detection of synergistic interactions of polyvinyl alcohol– cassava starch blends through DSC  

Microsoft Academic Search

The synergistic interaction of polyvinyl alcohol (PVOH) and cassava starch was studied by differential scanning calorimetry (DSC) method. Film of the PVOH–cassava starch blends were prepared by solution cast method. Originally, cassava starch film did not show presence of any endothermic peaks in DSC thermogram. However, after adding PVOH to cassava starch, the PVOH–cassava starch blend films showed obvious endothermic

Lee Tin Sin; W. A. W. A. Rahman; A. R. Rahmat; M. I. Khan

2010-01-01

280

Linear Dichroism of Cyanine Dyes in Stretched Polyvinyl Alcohol Films: A Physical Chemistry Laboratory Experiment.  

ERIC Educational Resources Information Center

Provides background information, procedures, and results of an undergraduate physical chemistry experiment on the polarization of absorption spectra of cyanine dyes in stretched polyvinyl alcohol films. The experiment gives a simple demonstration of the concept of linear dichromism and the validity of the TEM method used in the analyses. (JN)

Natarajan, L. V.; And Others

1983-01-01

281

FOAMED ARTICLES BASED ON POTATO STARCH, CORN AND WHEAT FIBRE, AND POLY(VINYL ALCOHOL)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Continued research cooperation between USDA Laboratories (USA) and the University of Pisa, Italy, has yielded several composites based on blends of poly(vinyl alcohol) (PVA) and either corn or wheat fibres, co-product of the corn-wheat wet-milling process. Foam trays were prepared by baking the blen...

282

INJECTION MOLDED HYBRID COMPOSITES BASED ON CORN FIBERS AND POLY(VINYL ALCOHOL).  

Technology Transfer Automated Retrieval System (TEKTRAN)

On going research cooperation between USDA and the University of Pisa, Italy has yielded several composite blends of poly(vinyl alcohol)(PVA) and corn fibers (CF). The USA is the largest producer of ethanol from cereal grains. Composites based on natural fibers alone are extremely sensitive to water...

283

Synthesis and characterization of hybrid polymeric networks (HPN) based on polyvinyl alcohol\\/chitosan  

Microsoft Academic Search

The aims of this study are the preparation of hybrid polymer network (HPN) hydrogels with slight differences in their hydrophilic balance and evaluate the influence of the chemical composition on the HPN for application as solid polymeric electrolytes (SPEs). A hydrogels series of polyvinyl alcohol (PVA)\\/chitosan (CHI) were prepared using glutaraldehyde as crosslinking agent. The hydrogels were characterized by Fourier

Isadora Reis Rodrigues; Maria Madalena de Camargo Forte; Denise Scherman Azambuja; Katia R. L. Castagno

2007-01-01

284

Development of structure in natural silk spinning and poly(vinyl alcohol) hydrogel formation  

Microsoft Academic Search

This research involves the characterization of structure and structure formation in aqueous systems. Particularly, these studies investigate the effect of various processing variables on the structure formation that occurs upon conversion from aqueous solution to fiber or hydrogel. The two processes studied include natural silk fiber spinning and physical gelation of poly(vinyl alcohol), PVOH, in water. The techniques employed combine

Patricia Jeanene Willcox

1998-01-01

285

Composite Nafion\\/polyvinyl alcohol membranes for the direct methanol fuel cell  

Microsoft Academic Search

The methanol crossover in the direct methanol fuel cell (DMFC) can be reduced by casting a thin film containing the mixture of polyvinyl alcohol (PVA) and Nafion on a commercial perfluorosulfonic membrane (Nafion, Dupont). In addition to the cell polarization testing, a design factor defined as the reciprocal of the multiplication of the methanol permeation current density and membrane area

Zhi-Gang Shao; Xin Wang; I.-Ming Hsing

2002-01-01

286

CHARACTERIZATION OF BIODEGRADABLE COMPOSITE FILMS PREPARED FROM BLENDS OF POLYVINYL ALCOHOL, CORNSTARCH AND LIGNOCELLULOSICC FIBER  

Technology Transfer Automated Retrieval System (TEKTRAN)

Several composite blends of poly(vinyl alcohol) (PVA) and lignocellulosic fibers were prepared and characterized. Cohesive and flexible cast films were obtained by blending lignocellulosic fibers derived from orange waste and PVA with or without cornstarch. Films were evaluated for their thermal s...

287

Hybrid composite based on poly(vinyl alcohol) and fillers from renewable resources  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hybrid composite laminates consisting of polyvinyl alcohol (PVA) as continuous phase (33% by weight) and lignocellulosic fillers, derived from sugarcane bagasse, apple and orange waste (22% by weight) were molded in a carver press in the presence of water and glycerol such as platicizers agents. Cor...

288

Pregnancy Following Uterine Artery Embolization with Polyvinyl Alcohol Particles for Patients with Uterine Fibroid or Adenomyosis  

Microsoft Academic Search

Purpose: To determine whether uterine fibroid embolization (UFE) with polyvinyl alcohol (PVA) particles affects fertility in women desiring future pregnancy. Methods: Of 288 patients managed with UFE with PVA particles for uterine myoma or adenomyosis between 1998 and 2001, 94 patients were enrolled in this study. The age range of participants was 20–40 years. The data were collected through review

Man Deuk Kim; Nahk Keun Kim; Hee Jin Kim; Mee Hwa Lee

2005-01-01

289

Micromechanics-Based Durability Study of Polyvinyl Alcohol-Engineered Cementitious Composite  

Microsoft Academic Search

The durability of engineered cementitious composites (ECC) reinforced with polyvinyl alcohol (PVA) fiber is investigated in this paper. ECCs have been realized as ductile strain-hardening cementitious composites with tensile strain capacity up to 5%. This material is being applied in new construction and for the repair and retrofit of structures. A micromechanics-based approach is adopted in the present durability study.

Victor C. Li; Tetsuo Horikoshi; Atsuhisa Ogawa; Shinichi Torigoe; Tadashi Saito

290

Embolization of Cerebral Arteriovenous Malformations Achieved with Polyvinyl Alcohol Particles: Angiographic Reappearance and Complications  

Microsoft Academic Search

BACKGROUND AND PURPOSE: The appropriate choice of embolic materials with respect to the permanency of obliterated nidi after embolization and complications related to the pro- cedure is essential for safe and effective embolization of cerebral arteriovenous malformations (AVMs). Our purpose was to ascertain the recanalization and complication rates after AVM treatment with polyvinyl alcohol (PVA) particles. METHODS: Between 1988 and

Takatoshi Sorimachi; Tetsuo Koike; Shigekazu Takeuchi; Takashi Minakawa; Hiroshi Abe; Keiichi Nishimaki; Yasushi Ito; Ryuichi Tanaka

291

Linear Dichroism of Cyanine Dyes in Stretched Polyvinyl Alcohol Films: A Physical Chemistry Laboratory Experiment.  

ERIC Educational Resources Information Center

|Provides background information, procedures, and results of an undergraduate physical chemistry experiment on the polarization of absorption spectra of cyanine dyes in stretched polyvinyl alcohol films. The experiment gives a simple demonstration of the concept of linear dichromism and the validity of the TEM method used in the analyses. (JN)|

Natarajan, L. V.; And Others

1983-01-01

292

Compatibility of Polyvinyl Alcohol with the 241-F/H Tank Farm Liquid Waste  

SciTech Connect

This report describes results from laboratory-scale oxidative mineralization of polyvinyl alcohol (PVA), and the evaluation of the F/H Tank Farms as a storage/disposal option for PVA waste solution generated in the Canyons and B-line decontamination operations.

Oji, L.N.

1998-11-25

293

Testing of polyvinyl alcohol and starch mixtures as biodegradable polymeric materials  

Microsoft Academic Search

The mechanical properties, thermal behaviour and biodegradation of some polymeric materials based on polyvinyl alcohol and starch, in the presence of urea (used as a micro-organism nitrogen source\\/plasticizer) and glycerine (used as a plasticizer) have been studied. The chemical composition optimization of the analysed blends was carried out using a second order factorial experimental design. The progress of biodegradation was

N Tudorachi; C. N Cascaval; M Rusu; M Pruteanu

2000-01-01

294

Blended chitosan and polyvinyl alcohol membranes for the pervaporation dehydration of isopropanol  

Microsoft Academic Search

Homogeneous membranes were prepared by casting the solution of blended chitosan and polyvinyl alcohol (PVA) on a glass plate. The percent weight of chitosan in the membrane was varied from 0 to 100%. The membrane thickness was in the range of 15–30?m. The membranes were heat treated at 150°C for an hour. After that the membranes were crosslinked by glutaraldehyde

A. Svang-Ariyaskul; R. Y. M. Huang; P. L. Douglas; R. Pal; X. Feng; P. Chen; L. Liu

2006-01-01

295

Embolization of intracranial arteriovenous malformations and fistulas with polyvinyl alcohol particles and platinum fibre coils  

Microsoft Academic Search

In order to reduce the recanalization rate of arteriovenous malformations and multiple dural arteriovenous fistulas, embolization was carried out with polyvinyl alcohol (PVA) particles combined with platinum fibre coils in 20 patients. The malformation was occluded more effectively than by PVA alone. Distal deposition of the emboli was obtained by improved steerable catheters (Tracker-18-unibody) and guidewires. The complication rate was

P. H. Nakstad; S. J. Bakke; J. K. Hald

1992-01-01

296

Hybrid composite based on poly(vinyl alcohol) and fillers from renewable resources  

Technology Transfer Automated Retrieval System (TEKTRAN)

Hybrid composite laminates consisting of polyvinyl alcohol (PVA) as continuous phase and lignocellulosic fibres, derived from sugarcane bagasse, apple and orange waste were moulded in a carver press in the presence of water and glycerol such as platicizers agents. Corn starch was introduced as a bio...

297

The use of a new grade of polyvinyl alcohol for stabilising tissue sections during histochemical incubations  

Microsoft Academic Search

1.The use of a new grade of polyvinyl alcohol (PVA) is described for maintaining tissue integrity during histochemical incubations. The new material has several advantages over the PVA currently used. It is somewhat less viscous and easier to prepare, and it has no reducing effect upon tetrazolium salts.2.No losses of nitrogenous material, or of the “soluble” enzyme 6 phosphogluconate dehydrogenase,

F. P. Altman; Terence Kennedy

1971-01-01

298

Efficacy of Trisacryl Gelatin Microspheres versus Polyvinyl Alcohol Particles in the Preoperative Embolization of Meningiomas  

Microsoft Academic Search

BACKGROUND AND PURPOSE: Trisacryl gelatin microspheres are a new, commercially available nonabsorbable embolic agent. The purpose of this study was to evaluate their efficacy in the preoperative embolization of meningiomas as compared with polyvinyl alcohol (PVA) particles of various sizes. METHODS: In 30 consecutive patients, trisacryl gelatin microspheres (150-300 mm) were used for the preoperative superselective embolization of meningiomas (group

Martin Bendszus; Rudiger Klein; Ralf Burger; Monika Warmuth-Metz; Erich Hofmann; Laszlo Solymosi

299

Preliminary study of polyvinyl alcohol-hydrogel (PVA-H) artificial meniscus  

Microsoft Academic Search

Nowadays the importance of knee meniscal function is recognized. The treatment for meniscus injury has been changing from resection to repair. However, depending on the type of injury, meniscectomy cannot be avoided. In consideration of the prognosis in such patients, we developed artificial meniscus using polyvinyl alcohol-hydrogel (PVA-H) with a high water content and performed an animal experiment as preliminary

Masanori Kobayashi; Jyunya Toguchida; Masanori Oka

2003-01-01

300

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

Microsoft Academic Search

Polymer gels are crosslinked polymer networks swollen by a fluid. If magnetic particles either as powder or dispersed in a magnetic fluid are introduced into the gel then the system becomes sensitive to external magnetic fields and the resulting material is called ferrogel. The polyvinyl alcohol (PVA) magnetite ferrogels system has properties that are attractive for artificial muscles and drug

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

2008-01-01

301

Synthesis of poly(vinyl alcohol)–magnetite ferrogel obtained by freezing–thawing technique  

Microsoft Academic Search

Polymer gels are crosslinked polymer networks swollen by a fluid. If magnetic particles either as powder or dispersed in a magnetic fluid are introduced into the gel then the system becomes sensitive to external magnetic fields and the resulting material is called ferrogel. The polyvinyl alcohol (PVA)–magnetite ferrogels system has properties that are attractive for artificial muscles and drug delivery

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

2008-01-01

302

Piezoelectric textures based on poly(vinyl chloride) filled with dispersed lead zirconate titanate (PZT-19)  

NASA Astrophysics Data System (ADS)

This paper reports on the results in investigations into the properties of piezoelectric textured materials that are formed through technological treatment of a mixture of components of dispersed poly(vinyl chloride) and a ferroelectric powder with the application of an external mechanical shear stress and an electric field.

Luchnikov, A. P.; Sigov, A. S.

2009-07-01

303

Characterization methods for radiation crosslinked poly(vinyl methyl ether) hydrogels  

Microsoft Academic Search

The paper reviews recent results of radiation crosslinking of poly(vinyl methyl ether) (PVME). It will give an overview of possible characterization methods for both, soluble and crosslinked PVME. The irradiation of aqueous low concentrated PVME solutions with ?-rays of low doses results in structural changes of PVME molecules. We are able to monitor changes in the chemical structure by spectroscopic

Thomas Schmidt; Claudia Querner; Karl-Friedrich Arndt

2003-01-01

304

Internal Treatment of Paper Sheets from Wood and Bagasse Pulps with Polyvinyl Alcohol  

Microsoft Academic Search

Mechanical strength and optical properties of paper sheets prepared from polyvinyl alcohol (PVA)-treated wood and bagasse pulps were investigated. The effects of the percentage of added PVA, the amount and type of polymer precipitant, and the manner of polymer addition (before or after the beating stage) on the properties of prepared sheets were presented. Studies were also carried out to

Nabila A. El-Shinawy; Altaf H. Basta; Samira F. Yacoub; Samar H. Mohamed

1998-01-01

305

Dynamic mechanical behavior of the dioctyl phthalate plasticized polyvinyl chloride–epoxidized soya bean oil  

Microsoft Academic Search

The mixing of polyvinyl chloride (PVC) with dioctyl phthalate (DOP) shows two stages of gelation and fusion, but the homogeneity of each stage is influenced by the thermal stability of PVC and its rheological behavior. A torque rheometer has been used to gather almost all critical data related to the plasticized PVC in the epoxidized soya bean oil (ESBO). This

M. A Semsarzadeh; M Mehrabzadeh; S. S Arabshahi

2002-01-01

306

Oxidative mineralization and characterization of polyvinyl alcohol for compatibility with tank farm processing chemistry  

Microsoft Academic Search

Polyvinyl alcohol (PVA) material has been evaluated for use as a cost-effective substitute for conventional cellulose-based disposal materials (decontamination mops and wipes), plastic bags, and disposable personal protection clothing, that are currently used at Savannah River Site. This study also provides process design criteria for ultraviolet\\/ultrasonic\\/hydrogen peroxide PVA reactor system.

Oji

2000-01-01

307

Effect of PolyVinyl Pyrrolidone on Sperm Membrane Integrity and Chromatin Status  

Microsoft Academic Search

Background: The aim of present study is to evaluate the effect of PolyVinyl Pyrrolidone (PVP) routinly used during ICSI procedure on sperm membrane integrity, and sperm chromatin status. Materials and Methods: This study was carried out on 21 semen samples from the infertile men referring to Isfahan Fertility and Infertility Center. The processed semen samples were divided into two portions.

Mohammad Hossein; Nasr Esfahani; Shahnaz Razavi

308

Oxidative Mineralization and Characterization of Polyvinyl Alcohol Solutions for Wastewater Treatment  

SciTech Connect

The principal objectives of this study are to identify an appropriate polyvinyl alcohol (PVA) oxidative mineralization technique, perform compatibility and evaporation fate tests for neat and mineralized PVA, and determine potential for PVA chemical interferences which may affect ion exchange utilization for radioactive wastewater processing in the nuclear industry.

Oji, L.N.

1999-08-31

309

Electrospun nanofibers of poly(vinyl alcohol)reinforced with cellulose nanofibrils  

Technology Transfer Automated Retrieval System (TEKTRAN)

In this work, nanofibers of poly(vinyl alcohol) (PVA) reinforced with cellulose nanofibrils (CnF) were produced by electrospinning. The effects of applied voltage, polymer concentration and injection rate, tip-to-collector distance (TCD), rotation speed of the collector, and relative humidity on mor...

310

In vitro nuclear maturation of bitch oocytes in the presence of polyvinyl-pyrrolidone  

Microsoft Academic Search

The main limitation in producing in vitro dog embryos succesfully is the low oocyte maturation rate to the Metaphase II stage. The objective of this experiment was to compare the rates of nuclear maturation of dog oocytes cultured in Tissue Culture Medium 199 (TCM 199) supplemented with polyvinyl-pirrolidone (PVP) with oocytes cultured in TCM 199 with estrous cow serum (ECS)

L. C. Santos; B. A. Rodrigues; J. L. Rodrigues

311

True stabilization: the behaviour of lead compounds against the thermal decomposition of polyvinyl chloride  

Microsoft Academic Search

Investigations which have been conducted within the last two decades into the behaviour of basic lead compounds as stabilizers against the thermal dehydrochlorination of polyvinyl chloride are summarized. It is shown that the results can be explained satisfactorily in terms of a free radical dehydrochlorination mechanism and a regenerative exchange process which interferes with the dehydrochlorination. This may be regarded

E. W. J. Michell

1985-01-01

312

Effects of poly-vinyl alcohol on supercooling phenomena of water  

Microsoft Academic Search

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

Hiroyuki Kumano; Tetsuo Hirata; Tomoya Kudoh

2009-01-01

313

Comparison of storage stability of odorous VOCs in polyester aluminum and polyvinyl fluoride tedlar bags  

Technology Transfer Automated Retrieval System (TEKTRAN)

Whole air sampling using containers such as flexible bags or rigid canisters is commonly used to collect samples of volatile organic compounds (VOC) in air. The objective of this study was to compare the stability of polyester aluminum (PEA) and polyvinyl fluoride (PVF, brand name Tedlar®) bags for ...

314

Enhanced Degradation of Polyvinyl Alcohol by Pycnoporus cinnabarinus after Pretreatment with Fenton's Reagent  

PubMed Central

Degradation of polyvinyl alcohol (PVA) was investigated by using a combination of chemical treatment with Fenton’s reagent and biological degradation with the white rot fungus Pycnoporus cinnabarinus. Inclusion of the chemical pretreatment resulted in greater degradation of PVA than the degradation observed when biological degradation alone was used.

Larking, Daniel M.; Crawford, Russell J.; Christie, Gregor B. Y.; Lonergan, Greg T.

1999-01-01

315

Films from spruce galactoglucomannan blended with poly(vinyl alcohol), corn arabinoxylan and konjac glucomannan  

Technology Transfer Automated Retrieval System (TEKTRAN)

The improvement of mechanical properties of spruce galactoglucomannan (GGM)-based films was sought by blending GGM with each of poly(vinyl alcohol) (PVOH), corn arabinoxylan (cAX), and konjac glucomannan (KGM). The blend ratios were 3:1, 1:1, and 1:3(w/w), and in addition films were made from each o...

316

Poly(vinyl alcohol) hydrogels. Formation by electron beam irradiation of aqueous solutions and subsequent crystallization  

Microsoft Academic Search

Aqueous solutions of poly(vinyl alcohol) were submitted to varying doses ; of electron beam irradiation. By modification of the classical Flory-Huggins ; equations, the molecular weight between crosslinks was calculated as a function ; of radiation dose, initial polymer concertration, and temperature. Following ; crosslinking in the solution state, crystallization was induced by dehydrating ; the network at temperatures above

James C. Bray; Edward W. Merrill

1973-01-01

317

Acute health effects among firefighters exposed to a polyvinyl chloride (PVC) fire  

Microsoft Academic Search

Firefighters are frequently being called on to fight fires that are chemical in nature. In the aftermath of a chemical fire in Plainfield, New Jersey on March 20-21, 1985, the authors conducted a retrospective cohort study which surveyed 80 firefighters exposed to burning polyvinyl chloride (PVC) as well as 15 nonexposed firefighter subjects. By means of an 81-item symptom checklist,

J. S. Markowitz; E. M. Gutterman; S. Schwartz; B. Link; S. M. Gorman

1989-01-01

318

Oxidative mineralization and characterization of polyvinyl alcohol for compatibility with tank farm processing chemistry  

SciTech Connect

Polyvinyl alcohol (PVA) material has been evaluated for use as a cost-effective substitute for conventional cellulose-based disposal materials (decontamination mops and wipes), plastic bags, and disposable personal protection clothing, that are currently used at Savannah River Site. This study also provides process design criteria for ultraviolet/ultrasonic/hydrogen peroxide PVA reactor system.

Oji, L.N.

2000-01-04

319

Controlling the color of Lippmann holograms recorded in dichromated gelatin polyvinyl alcohol  

NASA Astrophysics Data System (ADS)

The polyvinyl alcohol and several other organic materials are mixed into the aqueous gelatin while the film is coated. This thin solid film is sensitized by aqueous ammonium dichromate, so it is called a dichromated gelatin polyvinyl alcohol (DC-GPVA) holographic recording material. DC-GPVA not only possesses the same excellent holographic properties as the conventional dichromated gelatin (DCG) but also obviously improves its environmental stability. Experimental results have shown that the reconstruction wavelength of a Lippman hologram recorded in DC-GPVA can be shifted to longer or shorter wavelengths and freely controlled to a certain extent by varying the ratio of the gelatin and the polyvinyl alcohol and relative organic materials, or hardeners and its quantity, or heated temperature and heated time exerted on the drying films, or thickness of them. After the films are sensitized, they can be exposed by He-Cd or Ar+ laser (441.6 nm or 488.0 nm) and developed by the regular post processed method. Initial discussions are also presented about the functions and mechanisms of the polyvinyl alcohol and relative organic materials added into DC-GPVA.

Cai, Tiequan; Tang, Yixing; Wang, Hui; Dai, Chaoming; Guo, Lu-Rong

1993-03-01

320

Heparinized polyvinyl alcohol to specifically adsorb low-density lipoprotein from plasma  

Microsoft Academic Search

IntroductionA medical adsorbent for blood purification was developed to specifically adsorb low-density lipoprotein (LDL) from hypercholesterolemia patient’s plasma by covalently immobilizing heparin onto the surface of polyvinyl alcohol (PVA) with the couplant toluence-2,4-diisocyanate (TDI).

Kai-wang Ma; Xiao-zhen Dai; Shu-ying Feng; Ai-hua Jing; Jian-ying Yang

2011-01-01

321

Characterization of Poly(Vinyl Chloride) Aged in a Bromine Containing Electrolyte.  

National Technical Information Service (NTIS)

Poly(vinyl chloride) (PVC) is being considered for use as a flow frame material in a developmental zinc/bromine battery. The choice of PVC was based on its low cost and the ease with which it can be molded into complex parts. The electrolyte used in this ...

C. Arnold A. Leo M. Tarjani

1988-01-01

322

21 CFR 172.833 - Sucrose acetate isobutyrate (SAIB).  

Code of Federal Regulations, 2010 CFR

...3 2010-01-01 2009-04-01 true Sucrose acetate isobutyrate (SAIB). 172.833...CONSUMPTION Multipurpose Additives § 172.833 Sucrose acetate isobutyrate (SAIB). Sucrose acetate isobutyrate may be safely used in...

2010-01-01

323

21 CFR 172.833 - Sucrose acetate isobutyrate (SAIB).  

Code of Federal Regulations, 2010 CFR

... 2009-04-01 2009-04-01 false Sucrose acetate isobutyrate (SAIB). 172.833...CONSUMPTION Multipurpose Additives § 172.833 Sucrose acetate isobutyrate (SAIB). Sucrose acetate isobutyrate may be safely used in...

2009-04-01

324

Clostridium thermosaccharolyticum strain deficient in acetate production.  

PubMed Central

A mutant of Clostridium thermosaccharolyticum that is blocked in acetate production was isolated after treatment with nitrosoguanidine and selection for fluoroacetate resistance. The mutant produced more ethanol than the parent strain did.

Rothstein, D M

1986-01-01

325

Fragrance material review on 3-phenylpropyl acetate.  

PubMed

A toxicologic and dermatologic review of 3-phenylpropyl acetate when used as a fragrance ingredient is presented. 3-Phenylpropyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 3-phenylpropyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, skin sensitization, and toxicokinetics data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al., 2012 for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414651

McGinty, D; Letizia, C S; Api, A M

2012-03-04

326

Fragrance material review on anisyl acetate.  

PubMed

A toxicologic and dermatologic review of anisyl acetate when used as a fragrance ingredient is presented. Anisyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for anisyl acetate were evaluated, then summarized, and includes: physical properties, skin irritation, skin sensitization, elicitation, and phototoxicity data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al., 2012 for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414654

McGinty, D; Letizia, C S; Api, A M

2012-03-03

327

Fragrance material review on 4-methylbenzyl acetate.  

PubMed

A toxicologic and dermatologic review of 4-methylbenzyl acetate when used as a fragrance ingredient is presented. 4-Methylbenzyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 4-methylbenzyl acetate were evaluated, then summarized, and includes: physical properties, skin irritation, skin sensitization, and elicitation data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414643

McGinty, D; Letizia, C S; Api, A M

2012-03-05

328

Acetate Causes Alcohol Hangover Headache in Rats  

PubMed Central

Background The mechanism of veisalgia cephalgia or hangover headache is unknown. Despite a lack of mechanistic studies, there are a number of theories positing congeners, dehydration, or the ethanol metabolite acetaldehyde as causes of hangover headache. Methods We used a chronic headache model to examine how pure ethanol produces increased sensitivity for nociceptive behaviors in normally hydrated rats. Results Ethanol initially decreased sensitivity to mechanical stimuli on the face (analgesia), followed 4 to 6 hours later by inflammatory pain. Inhibiting alcohol dehydrogenase extended the analgesia whereas inhibiting aldehyde dehydrogenase decreased analgesia. Neither treatment had nociceptive effects. Direct administration of acetate increased nociceptive behaviors suggesting that acetate, not acetaldehyde, accumulation results in hangover-like hypersensitivity in our model. Since adenosine accumulation is a result of acetate formation, we administered an adenosine antagonist that blocked hypersensitivity. Discussion Our study shows that acetate contributes to hangover headache. These findings provide insight into the mechanism of hangover headache and the mechanism of headache induction.

Maxwell, Christina R.; Spangenberg, Rebecca Jay; Hoek, Jan B.; Silberstein, Stephen D.; Oshinsky, Michael L.

2010-01-01

329

Factors Affecting Acetate Degradation in Anaerobic Digesters.  

National Technical Information Service (NTIS)

Acetate is the major source of methane produced in anaerobic digestion, accounting for about two thirds of all the methane produced. The major methanogenic bacteria responsible for this reaction are /ital Methanosarcina barkeri/ and /ital Methanosarcina m...

R. A. Mah D. R. Boone

1988-01-01

330

Dioxouranium (VI) complexes with cellulose acetate  

Microsoft Academic Search

Dioxouranium [UO2(VI)] complexes with three degrees of substitution of cellulose acetate, prepared from viscose pulp (DS = 2.2, 2.45 and 2.86), have been synthesis and characterized. Degree of substitution (DS) is defined as the average number of CH groups substituted on each anhydrocellulose repeat unit. Probable structures of the cellulose acetate complexes were inferred from the elemental analysis data, conductance

Altaf H. Basta; Wafaa M. Hosny

1998-01-01

331

Minimizing acetate formation in E. coli fermentations  

Microsoft Academic Search

Escherichia coli remains the best-established production organism in industrial biotechnology. However, when aerobic fermentation runs at\\u000a high growth rates, considerable amounts of acetate are accumulated as by-product. This by-product has negative effects on\\u000a growth and protein production. Over the last 20 years, substantial research efforts have been expended on reducing acetate\\u000a accumulation during aerobic growth of E. coli on glucose. From

Marjan De Mey; Sofie De Maeseneire; Wim Soetaert; Erick Vandamme

2007-01-01

332

Delignification of Bagasse with Acetic Acid and Ozone. Part 1. Acetic Acid Pulping  

Microsoft Academic Search

Two-stage delignification of sugarcane bagasse with acetic acid and ozone was investigated. The better pulp was obtained pulping bagasse in aqueous solution of acetic acid (80% volume) at 145°C during 60 min. The liquor\\/bagasse ratio (L\\/B) was 10:1 and the kappa number was 44; it fell to 10 in the ozone stage due to selectivity of acetic acid medium. Pulp

H. Contreras Q; Z. A. Nagieb; R. Sanjuán D

1997-01-01

333

Characterization of the Acetate Binding Pocket in the Methanosarcina thermophila Acetate Kinase  

Microsoft Academic Search

Acetate kinase catalyzes the reversible magnesium-dependent synthesis of acetyl phosphate by transfer of the ATP -phosphoryl group to acetate. Inspection of the crystal structure of the Methanosarcina thermophila en- zyme containing only ADP revealed a solvent-accessible hydrophobic pocket formed by residues Val93, Leu122, Phe179, and Pro232 in the active site cleft, which identified a potential acetate binding site. The hypothesis

Cheryl Ingram-Smith; Andrea Gorrell; Sarah H. Lawrence; Prabha Iyer; Kerry Smith; James G. Ferry

2005-01-01

334

Non-aceticlastic methanogenesis from acetate: acetate oxidation by a thermophilic syntrophic coculture  

Microsoft Academic Search

Methanogenesis from acetate by a rod-shaped enrichment culture grown at 60° C was found to require the presence of two organisms rather than a single aceticlastic methanogen. A thermophilic Methanobacterium which grew on H2\\/CO2 or formate was isolated from the enrichment. Lawns of this methanogen were used to co-isolate an “acetate oxidizer” in roll tubes containing acetate agar. The rod-shaped

Stephen H. Zinder; Markus Koch

1984-01-01

335

Acetate Oxidation Is the Dominant Methanogenic Pathway from Acetate in the Absence of Methanosaetaceae†  

PubMed Central

The oxidation of acetate to hydrogen, and the subsequent conversion of hydrogen and carbon dioxide to methane, has been regarded largely as a niche mechanism occurring at high temperatures or under inhibitory conditions. In this study, 13 anaerobic reactors and sediment from a temperate anaerobic lake were surveyed for their dominant methanogenic population by using fluorescent in situ hybridization and for the degree of acetate oxidation relative to aceticlastic conversion by using radiolabeled [2-14C]acetate in batch incubations. When Methanosaetaceae were not present, acetate oxidation was the dominant methanogenic pathway. Aceticlastic conversion was observed only in the presence of Methanosaetaceae.

Karakashev, Dimitar; Batstone, Damien J.; Trably, Eric; Angelidaki, Irini

2006-01-01

336

Oxidation of 3- and 4-carenes with mercuric acetate in acetic acid  

Microsoft Academic Search

1.A study was made of the oxidation of 3-carene with Hg(OAc)2 in acetic acid at 23 and 86°, and with (HgOAc)2 at 90°. The action of both of the oxidizing agents leads to the same acetylative oxidation products: the acetates of p-mentha-1,5-dien-8-ol and p-mentha-1(7),5-dien-8-ol.2.The products of the oxidation of 4-carene with Hg(OAc)2 in acetic acid at 20° contain the acetates

B. A. Arbuzov; V. V. Ratner; Z. G. Isaeva; É. Kh. Kazakova; M. G. Belyaeva

1971-01-01

337

Stimuli-responsive mechanically adaptive polymer nanocomposites.  

PubMed

A new series of biomimetic stimuli-responsive nanocomposites, which change their mechanical properties upon exposure to physiological conditions, was prepared and investigated. The materials were produced by introducing percolating networks of cellulose nanofibers or "whiskers" derived from tunicates into poly(vinyl acetate) (PVAc), poly(butyl methacrylate) (PBMA), and blends of these polymers, with the objective of determining how the hydrophobicity and glass-transition temperature (Tg) of the polymer matrix affect the water-induced mechanically dynamic behavior. Below the Tg (approximately 60-70 degrees C), the incorporation of whiskers (15.1-16.5% v/v) modestly increased the tensile storage moduli (E') of the neat polymers from 0.6 to 3.8 GPa (PBMA) and from 2 to 5.2 GPa (PVAc). The reinforcement was much more dramatic above Tg, where E' increased from 1.2 to 690 MPa (PVAc) and approximately 1 MPa to 1.1 GPa (PBMA). Upon exposure to physiological conditions (immersion in artificial cerebrospinal fluid, ACSF, at 37 degrees C) all materials displayed a decrease in E'. The most significant contrast was seen in PVAc; for example, the E' of a 16.5% v/v PVAc/whisker nanocomposite decreased from 5.2 GPa to 12.7 MPa. Only a modest modulus decrease was measured for PBMA/whisker nanocomposite; here the E' of a 15.1% v/v PBMA/whisker nanocomposite decreased from 3.8 to 1.2 GPa. A systematic investigation revealed that the magnitude of the mechanical contrast was related to the degree of swelling with ACSF, which was shown to increase with whisker content, temperature, and polarity of the matrix (PVAc>PBMA). The mechanical morphing of the new materials can be described in the framework of both the percolation and Halpin-Kardos models for nanocomposite reinforcement, and is the result of changing interactions among the nanoparticles and plasticization of the matrix upon swelling. PMID:20305827

Shanmuganathan, Kadhiravan; Capadona, Jeffrey R; Rowan, Stuart J; Weder, Christoph

2010-01-01

338

Polyvinyl chloride. January 1980-February 1992 (Citations from the NTIS Data Base). Rept. for Jan 80-Feb 92  

SciTech Connect

The bibliography contains citations concerning preparation, properties, composition, toxicity, and health hazards of polyvinyl chloride. Topics include, aging tests, combustion products, occupational safety and health, photolysis, thermal degradation, and pollution. (Contains 116 citations with title list and subject index.)

Not Available

1992-01-01

339

Prodiginine (Prodigiosin-Like) Pigments from Streptoverticillium rubrireticuli, an Organism That Causes Pink Staining of Polyvinyl Chloride  

PubMed Central

Red pigments were extracted from Streptoverticillium rubrireticuli strain 100-19, an organism frequently incriminated in pink staining of polyvinyl chloride. These pigments were identified as undecylprodiginine and butylcycloheptylprodiginine.

Gerber, Nancy N.; Stahly, Donald P.

1975-01-01

340

Preparation of polyvinyl alcohol–silica hybrid heterogeneous anion-exchange membranes by sol–gel method and their characterization  

Microsoft Academic Search

Polyvinyl alcohol–silica hybrid heterogeneous anion-exchange membranes were prepared by sol–gel method by dispersing the anion-exchange resin in the gel formed by acid\\/base hydrolysis of tetraethylorthosilicate in polyvinyl alcohol solution. The effect of acid and base-catalyzed hydrolysis on membrane preparation and extent of resin loading was studied. Various membranes were prepared with 60% (w\\/w) anion-exchange resin (Indoin FFIP) loaded with different

R. K. Nagarale; Vinod K. Shahi; R. Rangarajan

2005-01-01

341

Electrical and spectroscopic characterization of polyaniline–polyvinyl chloride (PANI–PVC) blends doped with sodium thiosulphate  

Microsoft Academic Search

Polyaniline is doped with sodium thiosulphate in aqueous tetrahydrofuran (THF) and the blended films have been prepared by changing the amount of doped polyaniline (PANI) in the fixed amount of polyvinyl chloride (PVC). The electrical conductivity of various samples of polyaniline–polyvinyl chloride (PANI–PVC) blends has been studied to see the effect of dopant in the temperature range 300–400K. Mott's parameters

Sadia Ameen; Vazid Ali; M. Zulfequar; M. Mazharul Haq; M. Husain

2008-01-01

342

Dichromated poly(vinyl alchohol)-xanthene dye systems: holographic characterization and electron spin resonance spectroscopic study  

Microsoft Academic Search

Dichromated poly(vinyl alcohol)-xanthene dye (DCPVA-XD) systems have been employed as real-time holographic recording materials. In this paper, holographic characterization of dichromated poly(vinyl alcohol) with fluorescein (Fl), eosin Y (EY) and Rose Bengal (RB) is presented. In addition, a systematic ESR spectroscopic investigation was also performed on these systems. The photochemical evolution of Cr(V), Cr(III), polymer radical and dye radical in

Gurusamy Manivannan; Rupak Changkakoti; Roger A. Lessard; Gilles Mailhot; Michele Bolte

1994-01-01

343

Determination of butyltin and octyltin stabilizers in poly(vinyl chloride) products by headspace solid-phase microextraction and gas chromatography with flame-photometric detection.  

PubMed

Headspace solid-phase microextraction (HS-SPME) and gas chromatography with flame photometric detection (GC-FPD) have been investigated for determination of butyltin and octyltin stabilizers in poly(vinyl chloride) (PVC) products. The organotin stabilizers were first released from the plastic matrix by dissolving the PVC sample in tetrahydrofuran (THF). The stabilizers were then hydrolyzed to the chloride forms, by treatment with 6 mol L(-1) HCl, then derivatized with sodium tetraethylborate (NaBEt4) in 0.2 mol L(-1) sodium acetate buffer (pH 4.5) at 50 degrees C. HS-SPME was performed with a fused-silica fiber coated with a 100-microm film of polydimethylsiloxane (PDMS). The collected organotin compounds were then desorbed in the GC injector at 280 degrees C and analyzed by GC-FPD. Linearity (r > or =0.994) over a concentration of approximately two orders of magnitude was usually obtained. Limits of quantitation (LOQ) of the four organotin compounds studied, viz., monobutyltin (MBT), dibutyltin (DBT), monooctyltin (MOT), and dioctyltin (DOT), were in the range 0.3-1.0 ng Sn mL(-1). Recovery was >90% for butyltins and >80% for octyltins. The method was validated by analyzing two reference standard PVC sheets with known organotin content. The applicability of the method to analysis of organotin stabilizers in commercial PVC products was also demonstrated. PMID:16896617

Ou, Qin-Ren; Whang, Chen-Wen

2006-07-29

344

Application of mixtures of polymeric carriers for dissolution enhancement of fenofibrate using hot-melt extrusion.  

PubMed

Hot-melt extrusion was applied to improve dissolution behavior of poorly soluble model drug fenofibrate. Blends of polymers were used as carrier: copovidone (COP), polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol copolymer (PVCL-PVAc-PEG) and hypromellose 2910/5 (HPMC). The ratio of fenofibrate to COP remained constantly 1+3 (weighted parts) with varying amounts of PVCL-PVAc-PEG and HPMC. Solid state of fenofibrate was characterized by X-ray diffractometry and differential scanning calorimetry. Dissolution performance was compared to marketed formulations Lipidil and Lipidil-Ter. Stability studies were conducted at 25°C/60%rH. The dissolution rate from extrudates was significantly increased when compared to pure fenofibrate powder or physical mixture of the components. A supersaturation of 7.6-12.1 was reached with the pelletized extrudates. All extrudates were superior to marketed formulations. No recrystallization was observed after 26 weeks of storage for fenofibrate-COP extrudates 1+3 (weighted parts) with or without polymeric additives. Even so, both degree and duration of supersaturation decreased with increasing storage periods with the exception of fenofibrate-HPMC extrudates. Of particular interest is the finding that by adding polymers with differing release characteristics to the drug-carrier mixture, the dissolution performance of hot-melt extruded solid dosage forms can be readily adapted to meet specific requirements. PMID:22440149

Kalivoda, Adela; Fischbach, Matthias; Kleinebudde, Peter

2012-03-13

345

Friction and wear behaviour of acetal and nylon gears  

Microsoft Academic Search

The current paper will present an extensive investigation of polymer gear (acetal and nylon) friction and wear behaviour. First, a unique test method for polymer gear wear will be described in brief and later used in the extensive investigation of acetal and nylon gear wear. Initial tests were performed using acetal pinions with acetal gears, and nylon pinions with nylon

K. Mao; W. Li; C. J. Hooke; D. Walton

2009-01-01

346

Electrical and spectroscopic characterization of polyaniline polyvinyl chloride (PANI PVC) blends doped with sodium thiosulphate  

NASA Astrophysics Data System (ADS)

Polyaniline is doped with sodium thiosulphate in aqueous tetrahydrofuran (THF) and the blended films have been prepared by changing the amount of doped polyaniline (PANI) in the fixed amount of polyvinyl chloride (PVC). The electrical conductivity of various samples of polyaniline polyvinyl chloride (PANI PVC) blends has been studied to see the effect of dopant in the temperature range 300 400 K. Mott's parameters are used to explain the conduction mechanism. Different parameters such as pre-exponential factor (?0), activation energy (?E) and T0 have also been calculated to see the effect of chemical doping. The crystallinity of the blends is explained on the basis of T0. The calculated values of T0 show that crystallinity increases with an increase of doped PANI in PANI PVC blends. Fourier transform-infrared (FTIR) spectroscopy is done to explore the nature and interaction of dopant into the polymeric chain.

Ameen, Sadia; Ali, Vazid; Zulfequar, M.; Mazharul Haq, M.; Husain, M.

2008-08-01

347

Leaching of diethylhexyl phthalate from polyvinyl chloride bags into intravenous cyclosporine solution  

SciTech Connect

The release of diethylhexyl phthalate (DEHP) from flexible polyvinyl chloride containers into intravenous cyclosporine solutions was studied. Intravenous cyclosporine solution or solutions containing the vehicle Cremophor EL and alcohol in dextrose were prepared in an all-glass system and stored in polyvinyl chloride (PVC) bags. Four samples were obtained at different time intervals, and DEHP content was analyzed by gas chromatography. The amount of DEHP that was leached into solutions stored in the PVC bags increased as storage time increased. By 48 hours, nearly 33 mg of DEHP had leached into the solution. Intravenous cyclosporine solutions should be prepared in glass containers to minimize patient exposure to DEHP. If plastic bags are used for preparing cyclosporine injections, the injections must be used immediately after preparation.

Venkataramanan, R.; Burckart, G.J.; Ptachcinski, R.J.; Blaha, R.; Logue, L.W.; Bahnson, A.; Giam, C.S.; Brady, J.E.

1986-11-01

348

Bonding, vibrational, and electrical characteristics of CdS nanostructures embedded in polyvinyl alcohol matrix  

SciTech Connect

CdS nanocomposites have been grown in polyvinyl alcohol matrix by a chemical synthesis process. The transmission electron micrographs of nanocomposites synthesized at 70-90 deg. C temperature showed the growth of needlelike and junctionlike nanostructures. X-ray photoelectron spectroscopy analysis revealed the growth of stoichiometric CdS without the formation of any intermediate phases at the CdS-polyvinyl alcohol interface. Raman spectra of first order longitudinal optical phonon peak has been analyzed using phonon dispersion model to detect the surface phonon modes in CdS nanoneedles and wires. The origin of negative differential resistance behavior in current-voltage characteristics for junctionlike CdS nanocomposites has been discussed.

Mondal, S. P.; Dhar, A.; Ray, S. K. [Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur-721 302 (India); Chakraborty, A. K. [Laboratory for Mechanical Systems Engineering EMPA, Duebendorf, Zurich, CH-8600 (Switzerland)

2009-04-15

349

Sorption of boric acid by hydroxylic sorbents synthesized from polyvinyl alcohol and polyvinylene glycol  

SciTech Connect

It has been shown that sorbents synthesized from polyvinyl alcohol (PVA) and polyvinyl glycol (PVG) are the most effective agents for extraction of boron from natural waters and brines. The action of such sorbents is based on the ability of boric acid to form stable complexes with polyhydroxy compounds. In this work the authors studied hydroxylic sorbents differing in OH-group contents and in the amounts and nature of the cross-linking agent. The principal characteristics of the sorbents studied are given. The theoretical capacity was calculated on the assumption that the structural unit sorbing one boric acid molecule is -CH/sub 2/-CHOH-CH/sub 2/CHOH- in PVA and -CHOH-CHOH- in PVG.

Kisel'gof, G.V.; Arkhangel'skii, L.K.; Bochkova, N.A.

1986-10-10

350

Radiation chemical reduction of heptylviologens in polyvinyl alcohol under the action of x-radiation  

SciTech Connect

This paper presents an investigation of the radiation-chemical reduction of heptylviologen (HV/sup 2 +/) in a polyvinyl alcohol matrix; the method of steady-state radiolysis was used in the investigation. It was shown that the main radiolysis products of heptylviologen are the radical cations HV/sup +/. Their concentration passes through a maximum as the absorbed dose is increased. The radiation-chemical yield depends on the concentration of HV/sup 2 +/ and is equal to 18+/-2 at (HV/sup 2 +/) = 1.10/sup -1/ mole/dm/sup 3/. Radicals arising under the action of ionizing radiation on polyvinyl alcohol, in addition to electrons, participate in the reduction of HV/sup 2 +/.

Kolotilkin, A.S.; Krainov, I.P.; Mal'tsev, E.I.

1986-03-01

351

Polyvinyl alcohol-coated hybrid fiber grating for relative humidity sensing  

NASA Astrophysics Data System (ADS)

A relative humidity (RH) sensor based on a hybrid fiber grating coated with polyvinyl alcohol is proposed and demonstrated experimentally. The hybrid fiber grating is formed by superimposing a normal fiber Bragg grating (FBG) and a tilted-FBG around the same position of a single-mode fiber so that it can work in the reflection mode. Optical power of the reflected signal changes with the refractive index of the moisture sensitive polyvinyl alcohol, and humidity measurement can be realized. Experimental results show that the measurement range is 30 to 95% with the maximum sensitivity of 0.737 nW/% RH. The average response time is ~2 s and the measurement is nearly insensitive to temperature. Compared with the wavelength detection method used in normal FBG-based relative humidity sensors, the intensity demodulation method in this report is simpler and more cost-efficient.

Dong, Xinyong; Li, Tao; Liu, Yang; Li, Yi; Zhao, Chun-Liu; Chan, Chi Chiu

2011-07-01

352

Calcination of calcium acetate and calcium magnesium acetate: effect of the reacting atmosphere  

Microsoft Academic Search

The calcination process of the calcium acetate (CA) and calcium magnesium acetate (CMA) was investigated as a previous step for coal gas desulfurisation during sorbent injection at high temperatures because the excellent results demonstrated by these sorbents as sulfur removal agents both in combustion and gasification processes. As pore structure developed during calcination is one of the most important characteristic

J. Adánez; L. F. de Diego; F. Garc??a-Labiano

1999-01-01

353

Determination of odour detection thresholds for acetic acid and ethyl acetate in ice wine  

Microsoft Academic Search

Collectively acetic acid and ethyl acetate are responsible for ‘volatile acidity’ (VA) in wine. The detection limit or threshold for these compounds is well documented in table wine but not for ice wine. Knowledge of the ice wine thresholds is important for understanding perception limits and setting legal standards, particularly for a product with high intrinsic concentrations. Thresholds were determined

Margaret A. Cliff; Gary J. Pickering

2006-01-01

354

Factors affecting acetate degradation in anaerobic digesters  

SciTech Connect

Acetate is the major source of methane produced in anaerobic digestion, accounting for about two thirds of all the methane produced. The major methanogenic bacteria responsible for this reaction are )ital Methanosarcina barkeri) and )ital Methanosarcina mazei). One strain of each of these bacteria was selected for this study, in which the effect of molecular hydrogen on acetate dissimilation was examined. We examined the effects that hydrogen concentration had on the active growth of aceticlastic (acetate-splitting) cultures. We found that, during steady-state growth, each of these methanogens ()ital M. barkeri) or )ital M. mazei)) could tolerate a wide range of hydrogen concentrations with little change in their rates of acetate degradation. At hydrogen partial pressures as low as 2 Pa and as high as 800 Pa no change was detected in the growth rate or acetate degradation rate of either of these methanogens. However, we also showed that small amounts of hydrogen were produced or consumed by )ital Methanosarcina) in order to bring the hydrogen concentration in their environment to a pressure of 16 to 92 Pa, similar to that found in anaerobic digestors.

Mah, R.A.; Boone, D.R.

1988-01-01

355

Genera and species in acetic acid bacteria.  

PubMed

Taxonomic studies of acetic acid bacteria were historically surveyed. The genus Acetobacter was first introduced in 1898 with a single species, Acetobacter aceti. The genus Gluconobacter was proposed in 1935 for strains with intense oxidation of glucose to gluconic acid rather than oxidation of ethanol to acetic acid and no oxidation of acetate. The genus "Acetomonas" was described in 1954 for strains with polar flagellation and no oxidation of acetate. The proposals of the two generic names were due to confusion, and "Acetomonas" was a junior subjective synonym of Gluconobacter. The genus Acetobacter was in 1984 divided into two subgenera, Acetobacter and Gluconoacetobacter. The latter was elevated to the genus Gluconacetobacter in 1998. In the acetic acid bacteria, ten genera are presently recognized and accommodated to the family Acetobacteraceae, the Alphaproteobacteria: Acetobacteer, Gluconobacter, Acidomonas, Gluconacetobacter, Asaia, Kozakia, Swaminathania, Saccharibacter, Neoasaia and Granulibacter. In contrast, the genus Frateuria, strains of which were once named 'pseudacetic acid bacteria', was classified into the Gammaproteobacteria. The genus Gluconacetobacter was phylogenetically divided into two groups: the Gluconacetobacter liquefaciens group and the Gluconacetobacter xylinus group. The two groups were discussed taxonomically. PMID:18199517

Yamada, Yuzo; Yukphan, Pattaraporn

2007-12-05

356

Action of polyvinyl pyrrolidone on the interaction of polysilicic acid with human serum albumin monolayers  

Microsoft Academic Search

The interaction between polysilicic acid and human serum albumin monolayers can be inhibited by the action of polyvinyl pyrrolidone\\u000a (PVP). This effect is produced by a competition between the polymer and the protein for the silanol groups of polysilicic\\u000a acid. The results obtained show that in a substrate containing 0.30 g\\/l of SiO2 in form of polysilicic acid a concentration

J. Miñones; E. Iribarnegaray; S. Garcla Ferndndez; P. Sanz Pedrero

357

Controlled synthesis of gold nanosnakes assisted by poly(vinyl pyrrolidone)–sodium dodecyl sulphate aggregations  

Microsoft Academic Search

Anisotropic single-crystalline gold nanosnakes were synthesised in poly(vinyl pyrrolidone) (PVP)–sodium dodecyl sulphate (SDS) aggregation aqueous solution by reducing HAuCl4 with PVP without any additional reducing agent. The crystal structures, growth process and the influence of SDS concentrations on the growth of gold nanosnakes have been investigated by X-ray diffraction and transmittance electron microscopy. In this approach, the peculiar structure of

Yueping Ren; Jingjing Qi; Mengjie Wu; Yun Fang

2012-01-01

358

Reactions and stability of fluorinated poly(vinyl trimethylsilane) in electrochemical systems  

Microsoft Academic Search

Fluorinated poly(vinyl trimethylsilane) (FPVTMS) unlike virgin PVTMS is able to participate in electrochemical reactions and undergoes direct and indirect electrochemical reductive degradation. Specifically, its perfluorinated units are reduced irreversibly at a glass carbon electrode in a 0.05-M (C4H9)4ClO4 solution in dimethylformamide with subsequent splitting of C–F bonds and formation of conjugated double bonds in macromolecules at the polymer surface. On

A. A. Pud; S. P. Rogalsky; G. S. Shapoval; A. P. Kharitonov; V. V. Teplyakov; H. Strathmann; F. Poncin-Epaillard

2001-01-01

359

Optical Studies on Some Aspects of Polyvinyl Alcohol Composite Zns Nanocrystalline Thin Films  

NASA Astrophysics Data System (ADS)

Zinc Sulfide (ZnS) nanoparticles were grown into the polyvinyl alcohol (PVA) matrix and were synthesized at 70°C by chemical route. The particle size and surface morphology were analysed by X-ray diffraction (XRD), High Resolution Transmission Electron Microscopy (HRTEM) and Scanning Electron Microscopy (SEM). Optical absorption spectrum showed strong blue shift, which is an indication of strong quantum confinement. Photoluminescence spectrum shows the blue luminescence peaks, which can be attributed to the recombination of the defect states.

Barman, Bijoy; Mochahari, Prince Kumar; Sarma, Kanak Ch.

2011-10-01

360

Long-term performance of poly(vinyl chloride) cables, Part 2: Migration of plasticizer  

Microsoft Academic Search

Cable samples with plasticized poly(vinyl chloride) insulations were aged in air at temperatures between 80 and 155°C. The concentrations of the plasticizer (di-(2-ethylhexyl) phthalate, DEHP) in the insulations of the aged cables were determined by extraction of samples in tetrahydrofuran followed by analysis of the extract by liquid chromatography. The plasticizer concentration data for different ageing times were analysed by

M. Ekelund; B. Azhdar; M. S. Hedenqvist; U. W. Gedde

2008-01-01

361

Preparation and characterization of poly(vinyl sulfone)- and poly(vinylidene fluoride)-based electrolytes  

Microsoft Academic Search

A novel group of polymer electrolytes based on poly(vinyl sulfone) (PVS) and poly(vinylidene fluoride) (PVdF) polymers, plasticized with highly conductive solutions of LiClO4, LiN(CF3SO2)2 or LiAsF6 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

H. S. Choe; J. Giaccai; M. Alamgir; K. M. Abraham

1995-01-01

362

Evaluation of microstructure and photochromic behavior of polyvinyl alcohol nanocomposite films containing polyoxometalates  

Microsoft Academic Search

A series of photochromic nanocomposite films were prepared by well-dispersed Keggin type polyoxometalates (POM) in polyvinyl alcohol (PVA). The corresponding structure, photochromic behaviors and mechanism of the films were investigated with transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared spectra (FT-IR), ultraviolet visible absorption spectra (UV–vis) and electron resonance spectra (ESR). In composite films, the sphere-shaped POM

Li-Mei Ai; Wei Feng; Jie Chen; Yan Liu; Wei-min Cai

2008-01-01

363

Study of dielectric parameters of polyvinyl fluoride (PVF) by the thermostimulated currents (TSC) method  

Microsoft Academic Search

The thermally stimulated current method (TSC) is used to study the relaxation modes of the semicrystalline polyvinyle fluoride (PVF) polymer with a temperature that ranges (from -100°C to +100°C). The obtained spectrum shows three peaks as the temperature reaches -40°C, -1°C and +50°C. The shown peak at +50°C corresponds to the dielectric manifestation of the glass transition phenomenon and the

M. W. Khemici; N. Doulache; A. Gourari; M. Bendaoud

2010-01-01

364

Dielectric Behavior of Polyaniline\\/Polyvinyl Chloride\\/Nylon Fiber Composites at Microwave Frequencies  

Microsoft Academic Search

Polyaniline(PANI)\\/polyvinyl chloride(PVC)\\/nylon fiber composites were prepared by the chemical oxidative polymerization of aniline using ammonium persulphate initiator by the in situ technique. The composites were then cast into films and doped with hydrochloric acid. The dielectric properties were investigated using the cavity perturbation technique at room temperature. A rectangular cavity operating at S-band (2.4 GHz) was used. The dielectric properties were

Saritha A. Chandran; Sunil K. Narayanankutty

2008-01-01

365

Characterization of hydrophilic hollow fiber membranes prepared from poly(vinyl alcohol)  

Microsoft Academic Search

Hydrophilic hollow fiber membranes were prepared from a aqueous solution of poly(vinyl alcohol) (PVA) by a gel fiber spinning method. In order to control the water content of the hollow fiber membranes, the membranes were cross-linked physically by annealing, and then cross-linked chemically using glutaraldehyde (GA) solutions changing GA concentration. The diameter of the membranes was ca. 1.0 mm and

Mitsuru Higa; Kakuya Toyota; Takehiro Sugimoto

2010-01-01

366

Optical properties of poly(vinyl chloride)\\/poly(ethylene oxide) blend  

Microsoft Academic Search

The relatively high dielectric constant poly(vinyl chloride) (PVC) was blended with poly(ethylene oxide) (PEO) polymer electrolytes to improve their electrical conductivity from the optical spectra of the given polymeric system. The optical properties in the UV–visible region of PVC polymer containing 0%, 20%, 50% and 70% by weight PEO are reported. The optical results obtained were analyzed in terms of

Yahya Al-Ramadin

2000-01-01

367

gamma-irradiated chitosan-polyvinyl pyrrolidone hydrogels as pH-sensitive protein delivery system  

Microsoft Academic Search

The effects of pH of the buffer solution and the composition of the hydrogel system on the bovine serum albumin (BSA) adsorption capacity of chitosan (CS) polyvinyl pyrrolidone (PVP) (CSPVP) hydrogels and release of BSA were investigated. Poly-electrolyte CSPVP hydrogels with different compositions were prepared by irradiating CS\\/PVP\\/water mixtures with gamma-rays at ambient temperature. The adsorption capacity of hydrogels was

Sergey A. Dergunov; Grigoriy A. Mun

2009-01-01

368

?-irradiated chitosan-polyvinyl pyrrolidone hydrogels as pH-sensitive protein delivery system  

Microsoft Academic Search

The effects of pH of the buffer solution and the composition of the hydrogel system on the bovine serum albumin (BSA) adsorption capacity of chitosan (CS)–polyvinyl pyrrolidone (PVP) (CSPVP) hydrogels and release of BSA were investigated. Poly-electrolyte CSPVP hydrogels with different compositions were prepared by irradiating CS\\/PVP\\/water mixtures with ?-rays at ambient temperature. The adsorption capacity of hydrogels was found

Sergey A. Dergunov; Grigoriy A. Mun

2009-01-01

369

Poly(Vinyl Chloride)Lignin Blends for Outdoor Applicationin Building  

Microsoft Academic Search

The paper presents preliminary work carried out to prepare and evaluate the blends obtained from an unplasticized polyvinyl chloride) (PVC) compound, formulated with several loadings of TiO2 [between 0 and 10 parts per hundred parts (phr) PVC] and a kraft lignin (Tomlinite) in amounts up to 7.5 phr. A series of blends in which lignin (L) replaced partially or totally

D. Feldman; D. Banu; S. El-Raghi

1994-01-01

370

Entrapment of glucose oxidase in non-porous poly(vinyl chloride)  

Microsoft Academic Search

We have used solvent casting techniques to immobilise glucose oxidase (GOD) within unplasticised and plasticised poly(vinyl chloride) (PVC) matrices. The plasticisers studied were the cationic surfactant, tricaprylmethylammonium chloride (Aliquat 336s), the anionic surfactant bis(2-ethylhexyl) hydrogenphosphate (BEP) and the lipid, isopropylmyristate (IPM). The activity of the enzyme-membrane was tested by amperometric electrode. Changes in enzyme-membrane electrode response are rationalised on the

Subrayal M. Reddy; Pankaj Vadgama

2002-01-01

371

Thermal and Morphological Properties of Poly(vinyl alcohol) and Layered Double Hydroxide (LDH) Nanocomposites  

Microsoft Academic Search

Poly(vinyl alcohol) (PVA)\\/layered double hydroxide (LDH) nanocomposites were synthesized with different compositions: 0, 2, 4, 6, and 8 wt% of LDH by the solution intercalation method. The effects of the layered double hydroxide platelet concentration on the properties of the PVA\\/LDH films were investigated by thermogravimetric analysis (TGA), optical microscopy, and Fourier transform infrared spectroscopy (FTIR). A reduction in the onset

B. Ramaraj; S. N. Jaisankar

2008-01-01

372

Mechanisms of heat transfer on polyvinylchloride and poly(vinyl butyral)  

NASA Astrophysics Data System (ADS)

Results of experimental investigation and estimates of the contributions of the phonon, diffusion, and photon components of thermal conductivity of polyvinylchloride and poly(vinyl butyral) in the range 290 K ? T ? Tv + 40 K have been presented. It has been shown that the phonon mechanism of heat transfer predominates at 293 K ? T < Tv, and the diffusion mechanism, when T ? Tv. The value of the photon component of thermal conductivity nonlinearly decreases throughout the T range.

Kolupaev, B. B.; Klepko, V. V.; Lebedev, E. V.

2012-03-01

373

Vinyl chloride and polyvinyl chloride: Toxicology. (Latest citations from the Life Sciences Collection database). Published Search  

SciTech Connect

The bibliography contains citations concerning the toxicity of vinyl chloride and polyvinyl chloride following short- and long-term exposure. The citations explore how these compounds are metabolized and consider their carcinogenic and teratogenetic potential. Methodologies to quantitate their presence in atmospheric dust and body tissues are discussed. Occupational hazards are also noted.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

NONE

1995-12-01

374

Potassium sorbate release from poly(vinyl alcohol)-bacterial cellulose films  

Microsoft Academic Search

Active packaging materials are the subject of research because their performance exceeds that of traditional packaging. From\\u000a this class, antimicrobial materials extend the shelf-life of products and reduce the risk of contamination by pathogens. In\\u000a this paper, new composite materials with antimicrobial properties are obtained by using polyvinyl alcohol and bacterial cellulose\\u000a powder. Potassium (2E,4E)-hexa-2,4-dienoate was used as the antimicrobial

Iuliana Mihaela Jipa; Anicuta Stoica; Marta Stroescu; Loredana-Mihaela Dobre; Tanase Dobre; Sorin Jinga; Christu Tardei

375

In Situ Dynamic Vulcanization of Poly(Vinyl Chloride)\\/Acrylonitrile-butadiene Rubber Blends  

Microsoft Academic Search

Poly(vinyl chloride) (PVC)\\/acrylonitrile-butadiene rubber (NBR) blends can be obtained through a dynamic vulcanization process as a melt-processible thermoplastic elastomer which produces parts that look, feel and perform like vulcanized rubber with the advantage of being processible as a thermoplastic material. In this study, a vulcanized thermoplastic was obtained by in situ dynamic vulcanization of PVC\\/NBR blends using a sulphur\\/ tetramethylthiuram

Fábio Roberto Passador; Antonio Rodolfo Jr; Luiz Antonio Pessan

2009-01-01

376

Characterization of hydrogels formed from acrylate modified poly(vinyl alcohol) macromers  

Microsoft Academic Search

Poly(vinyl alcohol) was modified with pendent acrylate groups to form a macromer that was crosslinked via photopolymerization. Polymerization behavior was studied for several initial macromer concentrations using DSC and Near-IR spectroscopy. Under mild photoinitiating conditions (e.g. 0.05wt% initiator and less than 20mW\\/cm2 of 365nm light), the hydrogels polymerized to 100% conversion in less than 5min. To characterize the network structure,

P. Martens; K. S. Anseth

2000-01-01

377

Compatible poly(vinyl chloride)\\/chlorinated polyurethane blends: thermal characteristics  

Microsoft Academic Search

The thermal behaviour of a series of solution-cast blends of poly(vinyl chloride)\\/chlorinated 2,4-toluenediisocyanate-based polyurethane (PVC\\/CPU) polymers has been examined using differential scanning calorimetry, scanning electron microscopy and thermogravimetric analysis either alone or coupled with infrared spectroscopy. It has been found that the decomposition proceeds through a two-step route; the main, decisive degradation stage in the 200–320°C temperature range was found

Krzysztof Pielichowski; Ian Hamerton

2000-01-01

378

Inclusion Compound of Poly(vinyl alcohol) with Multivalent Molybdenum Coordination Compound  

Microsoft Academic Search

An inclusion compound of Mo(VI,V,IV) complexes and poly(vinyl alcohol) (PVA) that contains some carbonyl groups was prepared by a photoelectron transfer reaction between PVA and 12-molybdophosphoric acid (PMo12). A dark-blue film was obtained when the aqueous solution of PMo12 and PVA was irradiated with UV light. The film exhibited the characteristic electron spin resonance (ESR) signal of Mo(V). The existence

Cheng Xiansu; Guan Huaimin; Su Yingcao; Wang Jiafang

2001-01-01

379

Poly(vinyl alcohol)-based polymer electrolyte membranes containing polyrotaxane  

Microsoft Academic Search

Polymer electrolyte membranes featuring ionic channels have been prepared by sulfonation of crosslinked poly(vinyl alcohol)\\/polyrotaxane membranes. The ionic channels were prepared using rod-like polyrotaxanes, created as an inclusion complex between poly(ethylene glycol) (PEG) and ?-cyclodextran. The size of the polyrotaxane was controlled by the molecular weight of PEG. Proton conductivity as well as methanol permeability increased as the amount of

Ji Hwan Son; Yong Soo Kang; Jongok Won

2006-01-01

380

Thermal behaviour and interactions of cassava starch filled with glycerol plasticized polyvinyl alcohol blends  

Microsoft Academic Search

Thermal behaviour and interactions of glycerol plasticized polyvinyl alcohol (PVOH)–cassava starch (CSS) blended films were analysed using thermogravimetry and differential scanning calorimetry methods. The outcomes showed that addition of glycerol has reduced the onset and end-point melting temperatures of the blended films. Samples with 30 and 40wt.% of PVOH–glycerol blended with CSS exhibited experimental enthalpy of melting (?Hm) lower than

W. A. W. A. Rahman; Lee Tin Sin; A. R. Rahmat; A. A. Samad

2010-01-01

381

Physical properties of poly(vinyl alcohol) fibers prepared from wet spinning\\/multi-step drawing  

Microsoft Academic Search

The preparation of poly(vinyl alcohol) (PVA) fibers by multi-step drawing was examined. The high draw ratio was attained when the drawing just before melting point was repeated. The influences of the draw ratio on mechanical and thermal properties of the fibers were studied. We utilized the wide angle x-ray diffraction (WAXD) as a medium to observe the erystallinity and the

Chin-An Link; Kuen-Shan Hwang; Chung-Hua Lin

1994-01-01

382

Properties and sorption studies of chitosan–polyvinyl alcohol blend films  

Microsoft Academic Search

Chitosan–polyvinyl alcohol (PVA) blend films were prepared and characterized for mechanical and optical properties. Intermolecular interaction between chitosan–PVA blend was investigated using FTIR. Moisture sorption characteristics of chitosan–PVA blend at 25 °C were studied for water activities ranging from 0.11 to 0.92. The moisture content increased with increase in PVA concentration. The moisture sorption data were used to fit eight

P. C. Srinivasa; M. N. Ramesh; K. R. Kumar; R. N. Tharanathan

2003-01-01

383

Nucleation of polyvinyl alcohol crystallization by single-walled carbon nanotubes  

Microsoft Academic Search

Non-isothermal crystallization experiments were performed on poly(vinyl alcohol) mixed with single-walled carbon nanotubes. Non-isothermal crystallization experiments showed that nanotubes nucleate crystallinity at weight fractions as low as 0.1%. An Ozawa model was applied to the non-isothermal crystallization data, and this approach confirmed the results deduced from the qualitative examination of the data: there was a clear difference in crystallization kinetics

Olga Probst; Eric M. Moore; Daniel E. Resasco; Brian P. Grady

2004-01-01

384

Film dosimeters based on methylene blue and methyl orange in polyvinyl alcohol  

SciTech Connect

Polyvinyl alcohol (PVA) films containing methylene blue and methyl orange are useful as gamma and electron radiation dosimeters. Absorbed doses should not exceed 40 kGy for methylene blue and 500 kGy for methyl orange. Because PVA is water-soluble, the films may be made without toxic solvents. The effects of irradiation temperature and humidity on the radiation response of the dosimeter films are discussed.

Chung, W.H. (Pusan National Univ. (Korea, Republic of). Dept. of Physics); Miller, A. (Risoe National Lab., Roskilde (Denmark))

1994-05-01

385

Congo red/polyvinyl alcohol film dosimeter for gamma rays and electrons  

SciTech Connect

Polyvinyl alcohol films containing congo red are useful as gamma and electron radiation dosimeters. Absorbed doses should not exceed 500 kGy. The dose response is rather linear in a higher range, e.g., 100 to 500 kGy. The film is relatively stable before and after irradiation for quite a long time against fading, for example, a change of [approximately]10% in 1 yr following irradiation at room temperature.

Woon Hyuk Chung (Pusan National Univ. (Korea, Republic of). Dept. of Physics)

1994-03-01

386

Viscoelastic properties of poly(vinyl alcohol) hydrogels and ferrogels obtained through freezing–thawing cycles  

Microsoft Academic Search

We report the preparation of poly(vinyl alcohol) (PVA) hydrogels obtained through freezing–thawing cycles. The viscoelastic properties of these gels using parallel-plate shear mode were evaluated as a function of temperature, time, degree of swelling, concentration and the number of freezing–thawing cycles. The storage modulus was analyzed on the basis of a theoretical model based on the scaling approach. These results

Rebeca Hernández; Aurélie Sarafian; Daniel López; Carmen Mijangos

2004-01-01

387

Preparation and Characterization of Blend Films of Poly(Vinyl Alcohol) and Sodium Alginate  

Microsoft Academic Search

Blend films of poly(vinyl alcohol) (PVA) and sodium alginate (NaAlg) were prepared by casting from aqueous solutions. This blend films were characterized by tensile strength test, Fourier transform infrared spectroscopy (FT?IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The miscibility in the blends of PVA and NaAlg was established on the basis of the thermal analysis results. DSC showed

Tuncer Çaykara; Serkan Demirci

2006-01-01

388

Blood interactions with plasticized poly(vinyl chloride): relevance of plasticizer selection  

Microsoft Academic Search

An investigation has been made of blood interactions with plasticized poly(vinyl chloride) (PVC) biomaterials in tubular form, taking into account the influence on the blood response of the polymer, antithrombotic agent, blood condition and test procedure. In vitro and ex vivo procedures were used to achieve a comparison between PVC plasticized with di- (2-ethylhexyl)phthalate (DEHP) and with tri-(2-ethylhexyl)trimellitate (TEHTM). The

H. Q. Yin; X. B. Zhao; J. M. Courtney; C. R. Blass; R. H. West; G. D. O. Lowe

1999-01-01

389

Swelling of polyvinyl alcohol, melamine and urethane treated southern pine wood  

Microsoft Academic Search

Anti-swelling properties of southern pine wood treated with polyvinyl alcohol (PVA) or melamine or\\u000a urethane were evaluated by measuring the tangential swelling and water uptake using AWPA standards methods.\\u000a The water-repellency efficiency (WRE) of melamine and PVA treated wafers exhibited values 80% superior\\u000a to untreated wafers. This study confirms that waterborne solution containing 3% of melamine or 3% of PVA

S. R. Shukla; D. Pascal Kamdem

2010-01-01

390

Polyvinyl butyral films containing leuco-malachite green as low-dose dosimeters  

NASA Astrophysics Data System (ADS)

Thin films containing leuco-malachite green (LMG) dye in polyvinyl butyral (PVB) have been developed for dose measurements of a few hundreds Gy level. The film shows significant color change in the visible range, and the sensitivity of the film to absorbed dose was enhanced by addition of chloride-containing compounds, such as chloral hydrate or 2,2,2-trichloroethanol. The film is suitable as dosimeters for dose measurements, e.g. in food irradiation and environmental protection.

Mai, Hoang Hoa; Solomon, H. M.; Taguchi, M.; Kojima, T.

2008-04-01

391

Some aspects of the ozone degradation of poly(vinyl alcohol)  

Microsoft Academic Search

Poly(vinyl alcohol) (PVAL) forms a strong hydrogen-bond complex with ozone. The interaction energy is of the order of 47.3kJ\\/mol as calculated from the blue shift undergone by the ozone absorption band in the UV after its complexation with PVAL. This fact may have many important practical implications in the application of PVAL in wastewater treatment both in terms of O3

Franco Cataldo; Giancarlo Angelini

2006-01-01

392

Structure and dynamics of poly(vinyl alcohol) gels in mixtures of dimethyl sulfoxide and water  

Microsoft Academic Search

We reviewed our structure studies on poly(vinyl alcohol) (PVA) gels formed in the mixtures of dimethyl sulfoxide (DMSO) and water using various scattering methods, including wide-, small- and ultra-small-angle neutron scattering and light scattering. These studies revealed the hierarchic structure of PVA gels formed in DMSO\\/water (60\\/40 v\\/v) in a very wide spatial scale from 1 Å to several micrometers.

Toshiji Kanaya; Nobuaki Takahashi; Hiroki Takeshita; Masatoshi Ohkura; Koji Nishida; Keisuke Kaji

2012-01-01

393

Poly(vinyl alcohol) as a structure release layer for the microfabrication of polymer composite structures  

Microsoft Academic Search

While lift-off techniques are common in the fabrication of hard, silicon-based microelectromechanical systems (MEMS), these techniques are not yet in widespread use in soft lithography, where polymer materials are used to fabricate MEMS devices for biological applications (bioMEMS). We present fabrication steps that allow us to make use of poly(vinyl alcohol) as a structure release agent in bioMEMS microfabrication. The

Kweku A Addae-Mensah; Ronald S Reiserer; John P Wikswo

2007-01-01

394

Migration of Epoxidized Sunflower Oil and Dioctyl Phthalate from Rigid and Plasticized Poly(vinyl chloride)  

Microsoft Academic Search

The aim of this paper is the determination of the specific migration of epoxidized sunflower oil (ESO) from rigid and plasticized poly(vinyl chloride) (PVC) into food simulants. ESO was obtained by epoxidation of commercial sunflower oil and used as a thermal organic co-stabilizer for PVC. For that purpose, rigid and plasticized (0, 15, 30, and 45 wt% of dioctyl phthalate or

D. Atek; N. Belhaneche-Bensemra; M. Turki

2010-01-01

395

Thermogravimetric investigation of volatility of dioctyl phthalate from plasticized poly(vinyl chloride)  

Microsoft Academic Search

The process of volatilization of dioctyl phthalate (DOP) plasticizer from plasticized poly(vinyl chloride) (PVC) folies was studied by the method of isothermal thermogravimetry in the temperature range of 120–150°C. The investigated samples contained 10.15 to 37.11wt% of DOP. The rate constants of the process of plasticizer volatilization were calculated and the dependence of rate constant on the initial concentration of

Željko Mrkli?; Tonka Kova?i?

1998-01-01

396

Effects of supercritical extraction on the plasticization of poly(vinyl butyral) and dioctyl phthalate films  

Microsoft Academic Search

Supercritical extraction of organic phases from films containing poly(vinyl butyral) (PVB) binder and dioctyl phthalate (DOP) plasticizer was performed with CO2 and C2H4 at 35–75°C and 10–40 MPa for cycle times of 3 h. For films containing 60:40 wt.% PVB:DOP, extraction efficiencies near 50% were observed with either fluid at 75°C and 40 MPa, which suggests nearly complete removal of

Rajesh V. Shende; Melissa Kline; Stephen J. Lombardo

2004-01-01

397

Synthesis and Characterization of Poly(vinyl alcohol) Membranes with Quaternary Ammonium Groups for Wound Dressing  

Microsoft Academic Search

2-[(acryloyloxy)ethyl]Trimethylammonium chloride (AETMAC) was grafted onto poly(vinyl alcohol) (PVA) using ceric ammonium nitrate (CAN) as a redox initiator. A series of graft co-polymer (PVA-g-PAETMAC) membranes with different contents of AETMAC were prepared with a casting method. The incorporation of AETMAC into PVA chains was confirmed by element analysis and Fourier transform infrared spectroscopy. The effects of grafting on the thermal

Kuo-Yu Chen; Yu-Sheng Lin; Chun-Hsu Yao; Ming-Hsien Li; Jui-Che Lin

2010-01-01

398

Space-charge distributed relaxations in vacuum-deposited polyvinyl fluoride films  

Microsoft Academic Search

The thermally stimulated discharge behaviour of vacuum-deposited polyvinyl fluoride films (about 0022-3727\\/30\\/8\\/014\\/img7 thick) studied as a function of polarization temperature (313 - 453 K) and polarization field (1 - 0022-3727\\/30\\/8\\/014\\/img8) shows a single relaxation peak whose peak temperature, charge, activation energy and so on depend strongly on the polarization parameters. The peak has been attributed to space-charge distributed polarization due

Suresh Chand; G. D. Sharma; Subhas Chandra; R. Chandra

1997-01-01

399

Structure-Sensitive Liquid-Flowing Media Based on Polyvinyl Alcohol Compounds with Cellulose Esters  

Microsoft Academic Search

The class of structure-sensitive liquid-flowing media based on polyvinyl alcohol (PVA) compounds with water-soluble cellulose esters (carboxymethylcellulose, Na-CMC, methylcellulose, MC) have been investigated. PVA may be used as an excellent structure-sensitive matrix for films and gels. Introduction of active additives allows for the formation of liquids whose structures changes under the action of external fields. Introduction of additives, especially of

T. G. Lazareva; E. V. Vashuk

1996-01-01

400

Development of a Hypertrophic Ovarian Artery After Uterine Artery Embolization with Polyvinyl Alcohol Particles  

SciTech Connect

Uterine artery embolization (UAE) for the treatment of symptomatic leiomyomata has shown excellent short-term clinical efficacy and minimal complications, yet recurrences after successful treatments at mid- and long-term follow-up have been reported. Exact etiologies for such recurrences have not been fully understood. We present a case of symptom recurrence with the development of a hypertrophic ovarian artery after successful UAE with polyvinyl alcohol particles, successfully treated with ovarian and repeat UAEs.

Kim, Hyun S., E-mail: sikhkim@jhmi.edu; Paxton, Ben E. [Johns Hopkins University School of Medicine, Russell H. Morgan Department of Radiology and Radiological Science (United States)

2007-09-15

401

Preparation and Characterization of Modified Cellulose Fiber-Reinforced Polyvinyl Alcohol\\/Polypyrrolidone Hybrid Film Composites  

Microsoft Academic Search

In this work, cellulose was modified by using 2-(trifluromethyl)benzoylchloride by base catalyzed reaction. Modification of cellulose was confirmed by IR studies. The biodegradable composite films were developed by a film casting method using modified cellulose with poly(vinyl alcohol) and polypyrrolidone in different compositions. Film composites showed good biodegradability. Better barrier and mechanical properties showed by film composites as the percentage

Sandeep S. Laxmeshwar; S. Viveka; D. J. Madhu Kumar; Dinesha; R. F. Bhajanthri; G. K. Nagaraja

2012-01-01

402

Transparent and high gas barrier films based on poly(vinyl alcohol)\\/graphene oxide composites  

Microsoft Academic Search

Composites of poly(vinyl alcohol) (PVA) and graphene oxide (GO) were synthesized by a modified Hummers method and a solution-mixing method. GO was fully exfoliated in the PVA\\/GO composites. GO did not affect the crystallization of PVA during solvent evaporation. GO is itself an excellent gas barrier without any chemical reduction. The oxygen permeability of the PVA\\/GO (0.3wt.%) composite coated film

Hye Min Kim; Jung Kyoo Lee; Heon Sang Lee

2011-01-01

403

Effects of molecular weight and stereoregularity on biodegradation of poly(vinyl alcohol) by Alcaligenes faecalis  

Microsoft Academic Search

Summary The biodegradability of poly(vinyl alcohol) (PVA) was analyzed with respect to its molecular weight and stereoregularity using the isolated PVA-assimilating microbial strain,Alcaligenes faecalis KK314. The biodegradability of PVA was influenced by its stereoregularity, and the isotactic moiety was preferentially biodegraded. However, there is no difference in the biodegradability based on the molecular weight of PVA being larger than the

Shuichi Matsumura; Yukimasa Shimura; Koutaro Terayama; Takato Kiyohara

1994-01-01

404

Effect of impact modification on slow crack growth in poly(vinyl chloride)  

Microsoft Academic Search

The effect of impact modification on slow crack growth in a poly(vinyl chloride) (PVC) compound was examined in order to test a methodology for predicting long-term creep fracture from short-term tension-tension fatigue tests. In all cases the crack propagated in a stepwise manner through a crack tip craze zone. Step length was analyzed in terms of the Dugdale model for

T. E. Bernal-Lara; Y. Hu; J. Summers; A. Hiltner; E. Baer

2004-01-01

405

Studies on thermal stress of lac-polyvinyl butyral resin blends through specular reflectance spectra  

Microsoft Academic Search

Purpose – To study the changes occurring in lac-polyvinyl butyral (PVB) resin blends at molecular levels on baking the blends at 200°C for different intervals of time. It was also to ascertain the changes in key physico-chemical parameters of these blends, before and after applying thermal stress on these blends. Design\\/methodology\\/approach – Films of lac-PVB blends, applied on tin panels

D. Bhatia; M. Alam; P. C. Sarkar

2007-01-01

406

Preparation of the poly(vinyl alcohol)/layered double hydroxide nanocomposite  

SciTech Connect

Intercalated nanocomposite based on Mg, Al layered double hydroxide (LDH) and poly(vinyl alcohol) (PVA) was prepared using exfoliation-adsorption technique, and characterized by X-ray diffraction and thermal gravimetric analysis. The results suggest that the intercalated species are formed via the re-aggregation of the delaminated LDH lamellar with the interlayer spacing 14.5 A, and the thermal stability of the nanocomposite improved compared with the original PVA.

Li Baoguang; Hu Yuan; Zhang Rui; Chen Zuyao; Fan Weicheng

2003-10-01

407

Pulsed electron beam irradiation of dilute aqueous poly(vinyl methyl ether) solutions  

Microsoft Academic Search

A dilute aqueous solution of the temperature-sensitive polymer, poly(vinyl methyl ether) (PVME), was irradiated by a pulsed electron beam in a closed-loop system. At temperatures, below the lower critical solution temperature (LCST), intramolecular crosslinked macromolecules, nanogels, were formed. With increasing radiation dose D the molecular weights Mw increase, whereas the dimensions (radius of gyration Rg, hydrodynamic radius Rh) of the

Thomas Schmidt; Ireneusz Janik; S?awomir Kad?ubowski; Piotr Ula?ski; Janusz M. Rosiak; Rudolf Reichelt; Karl-Friedrich Arndt

2005-01-01

408

Studies of the interaction of polyvinyl pyrrolidone with reduced vat dyes using visible spectroscopy  

NASA Astrophysics Data System (ADS)

Interaction between polyvinyl pyrrolidone (PVP) and the reduced form of two anthraquinone vat dyes has been studied using the results of spectrophotometric measurements. These results indicate that different types of interaction are possible depending on the chemical constitution of the vat dye and the amount of PVP. Comparison has been made between this interaction behaviour and that which occurs between anions of a disazo dye and PVP under neutral and alkaline conditions.

Sheth, Geeta N.

409

Polyvinyl butyral as a dispersant for barium titanate in a non-aqueous suspension  

Microsoft Academic Search

Polyvinyl butyral (PVB) was used as a dispersant for BaTiO3 in a toluene-methanol system and its efficiency was evaluated by measuring the zeta potential and by a rheological study of the suspension. Addition of only 1.6 vol % low-molecular-weight (50 000) PVB is effective in making a well-dispersed suspension. But a lower concentration (0.6 vol %) of high-molecular-weight (200 000)

S. Bhattacharjee; M. K. Paria; H. S. Maiti

1993-01-01

410

Novel antibacterial fibers of quaternized chitosan and poly(vinyl pyrrolidone) prepared by electrospinning  

Microsoft Academic Search

The preparation of continuous defect-free fibers from quaternized chitosan derivative (QCh) has been achieved by electrospinning of mixed aqueous solutions of QCh with poly(vinyl pyrrolidone) (PVP). The average fiber diameter significantly decreases from 2800 to 1500nm on increasing the polyelectrolyte content. In order to impart to QCh\\/PVP electrospun fibers stability to water and water vapor, the fibers have been crosslinked

Milena Ignatova; Nevena Manolova; Iliya Rashkov

2007-01-01

411

Lithographic properties of novel acetal-derivatized hydroxy styrene polymers  

NASA Astrophysics Data System (ADS)

Lithographic properties of a variety of acetal-derivatized styrene based polymers are reported. The structural modifications in the polymers involve varying the size of the pendent acetal moiety. the lithographic performances of the resists containing structurally modified acetals were found to be superior to the conventional acetals. In the cases where the acidolysis products of the modified acetals are non-volatile alcohols, the post-exposure volatilization, film shrinkage and plasma etch resistance were found to be significantly improved.

Malik, Sanjay; Blakeney, Andrew J.; Ferreira, Lawrence; Maxwell, Brian; Whewell, Allyn; Sarubbi, Thomas R.; Bowden, Murrae J.; van Driessche, Willy; Fujimori, Toru; Tan, Shiro; Aoai, Toshiaki; Uenishi, Kazuya; Kawabe, Yasumasa; Kokubo, Tadayoshi

1999-05-01

412

Megestrol acetate-induced adrenal insufficiency.  

PubMed

Megestrol acetate is a synthetic progestin that has been used since the 1970s for the treatment of advanced cancer and subsequently to treat anorexia, cachexia and weight loss in AIDS patients. It has been shown that high doses or prolonged treatment with this drug may cause Cushing's syndrome, new-onset diabetes and suppression of plasma ACTH and cortisol levels. Megestrol acetate may cause suppression of the pituitary-adrenal axis due to the affinity of this compound for the glucocorticoid receptor. Recognising the glucocorticoid-like activity of megestrol and its effects at the axis level is important for the diagnosis of sub-clinical adrenal insufficiency. We present the case of a 74-year-old woman with infiltrating ductal breast carcinoma refractory to prolonged hormonal treatment with megestrol acetate, presenting with adrenal insufficiency. PMID:18411198

González Villarroel, Paula; Fernández Pérez, Isaura; Páramo, Concepción; Gentil González, Marta; Carnero López, Beatriz; Vázquez Tuñas, M Lidia; Carrasco Alvarez, Juan A

2008-04-01

413

The Reactions of Acetals with Ozone  

NASA Astrophysics Data System (ADS)

Data concerning the composition of the products of the ozonisation of acetals, the stoichiometry of the process, and the influence of substituents and the structure of acetals on their reactivity, the effect of the polarity of the medium, the activation parameters for the process, and the kinetic isotope effects are surveyed and analysed. At lowered temperatures the process proceeds via a heterolytic mechanism, while with increase of temperature the fraction of ozone consumed due to the formation of free radicals rises. The bibliography includes 60 references.

Rakhmankulov, D. L.; Kuramshin, E. M.; Zlotskii, S. S.

1985-06-01

414

Catalysis of an isotopic exchange between CO 2 and the carboxyl group of acetate by Methanosarcina barkeri grown on acetate  

Microsoft Academic Search

Cell suspensions of Methanosarcina barkeri (strain Fusaro) grown on acetate were found to catalyze the formation of methane and CO2 from acetate (30–40 nmol\\/min·mg protein) and an isotopic exchange between the carboxyl group of acetate and 14CO2 (30–40 nmol\\/min·mg protein). An isotopic exchange between [14C]-formate and acetate was not observed. Cells grown on methanol mediated neither methane formation from acetate

Bernhard Eikmanns; Rudolf K. Thauer

1984-01-01

415

Study of the complexation of iron (III) and iron (II) with thioamidated copolymers based on polyvinyl alcohol and polyacrylonitrile by Moessbauer spectroscopy  

SciTech Connect

The mechanism of the interaction of iron(III) with polymeric ligands of vibrous structure, viz., polyvinyl alcohol (PVA), a copolymer of polyvinyl alcohol and polyacrylonitrile (PVA-PAN), and a thioamidated copolymer of polyvinyl alcohol and polyacrylonitrile (PVA-PAN-T), has been established by Moessbauer spectroscopy. It has been found that Fe(III) is partially or completely reduced to Fe(II) during sorption and that both forms of iron coordinate the oxygen-containing functional groups of the polymers.

Turte, K.I.; Yakubov, K.M.; Sokhibov, S.S.; Kalontarova, E.Ya.; Kalontarov, I.Ya.

1988-04-01

416

A quantitative study of the effects of different grades of polyvinyl alcohol on the activities of certain enzymes in unfixed tissue sections  

Microsoft Academic Search

Synopsis  Different grades of the colloid stabilizer, polyvinyl alcohol, used for protecting unfixed cryostat sections during cytochemical reactions, may have different effects on enzymatic activity. The influence of three grades of polyvinyl alcohol on the activities of soluble, membrane-bound and membrane-enclosed enzymes has been investigated in unfixed sections; the activities were measured microdensitometrically.The largest molecular weight polyvinyl alcohol (G18\\/140, mol. wt.

B. Henderson; N. Loveridge; W. R. Robertson

1978-01-01

417

Structural design of ketal and acetal blocking groups in two-component chemically amplified positive DUV resists  

NASA Astrophysics Data System (ADS)

In the present study, protecting groups of moderate stability, such as acetals and ketals, were investigated as pendant blocking groups in polyvinyl phenols. Polymers were obtained by reacting enol ethers with the phenolic side groups to form acetal or ketal blocked phenols. Decomposition temperatures, glass transition temperatures, and molecular weights of the resulting polymers were monitored and correlated with the protecting group structure. Stability of the protecting groups can be explained by protonation occurring at either of the two oxygen sites, making two cleavage routes possible. Secondary reactions of the released protecting groups in the resist film were investigated and discussed. The structure of the protecting group was designed in order to meet basic resist properties such as resolution/linearity, DOF, post exposure delay latitude and thermal stability. A Canon FPA 4500 (NA equals 0.37) and a GCA XLS exposure tool (NA equals 0.53) were used for the optimization process. A preoptimized resist formulation based on the above criteria exhibits 0.23 micrometers line/space resolution, 0.8 micrometers focus latitude at 0.25 micrometers resolution and approximately two hours post exposure delay latitude.

Mertesdorf, Carlo; Muenzel, Norbert; Holzwarth, Heinz E.; Falcigno, Pasquale A.; Schacht, Hans-Thomas; Rohde, Ottmar; Schulz, Reinhard; Slater, Sydney G.; Frey, David; Nalamasu, Omkaram; Timko, Allen G.; Neenan, Thomas X.

1995-06-01

418

Synthesis of Cellulose Acetate from Cotton Byproducts  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cotton burr and cottonseed hull are relatively inexpensive cotton byproducts. In an effort to derive greater value out of these natural renewable materials, we have succeeded in converting part of them into cellulose acetate without prior chemical breakdown or physical separation of cellulose, ligni...

419

The PVT Properties of Acetic Acid.  

National Technical Information Service (NTIS)

The PVT properties of acetic acid in the saturated and single-phase regions were measured at temperatures between 448.15 and 603.15 K, at pressures up to about 10 MPa. The experimental results were corrected for decomposition of the sample.

D. A. Lee G. B. Lewis I. J. Lawrenson

1977-01-01

420

Calcium Magnesium Acetate Production and Cost Reduction,  

National Technical Information Service (NTIS)

Calcium Magnesium Acetate (CMA) has been found to be a much less corrosive and environmentally safer substance for effective highway de-icing. However, CMA costs are currently about $640 per ton, while road salt costs $25 per ton. In addition, present CMA...

A. P. Leuschner

1988-01-01

421

Fragrance material review on phenethyl acetate.  

PubMed

A toxicologic and dermatologic review of phenethyl acetate when used as a fragrance ingredient is presented. Phenethyl acetate is a member of the fragrance structural group aryl alkyl alcohol simple acid esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for phenethyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, toxicokinetics, repeated dose, genotoxicity, and carcinogenicity data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22414644

McGinty, D; Vitale, D; Letizia, C S; Api, A M

2012-03-05

422

Fragrance material review on ?-methylbenzyl acetate.  

PubMed

A toxicologic and dermatologic review of ?-methylbenzyl acetate when used as a fragrance ingredient is presented. ?-Methylbenzyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for ?-methylbenzyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, elicitation, and repeated dose data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22406576

McGinty, D; Letizia, C S; Api, A M

2012-03-03

423

Fragrance material review on piperonyl acetate.  

PubMed

A toxicologic and dermatologic review of piperonyl acetate when used as a fragrance ingredient is presented. Piperonyl acetate is a member of the fragrance structural group aryl alkyl alcohol simple acid esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for piperonyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, skin sensitization, toxicokinetics, and genotoxicity data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22445840

McGinty, D; Letizia, C S; Api, A M

2012-03-15

424

Fragrance material review on 2-phenylpropyl acetate.  

PubMed

A toxicologic and dermatologic review of 2-phenylpropyl acetate when used as a fragrance ingredient is presented. 2-Phenylpropyl acetate is a member of the fragrance structural group Aryl Alkyl Alcohol Simple Acid Esters (AAASAE). The AAASAE fragrance ingredients are prepared by reacting an aryl alkyl alcohol with a simple carboxylic acid (a chain of 1-4 carbons) to generate formate, acetate, propionate, butyrate, isobutyrate and carbonate esters. This review contains a detailed summary of all available toxicology and dermatology papers that are related to this individual fragrance ingredient and is not intended as a stand-alone document. Available data for 2-phenylpropyl acetate were evaluated, then summarized, and includes: physical properties, acute toxicity, skin irritation, mucous membrane (eye) irritation, and skin sensitization data. A safety assessment of the entire AAASAE will be published simultaneously with this document. Please refer to Belsito et al. (2012) for an overall assessment of the safe use of this material and all AAASAE in fragrances. PMID:22421639

McGinty, D; Letizia, C S; Api, A M

2012-03-06

425

Fermentative biohydrogen production from lactate and acetate.  

PubMed

In this study, a continuous-flow stirred tank reactor (CSTR) fed with lactate and acetate was operated to enrich hydrogen-producing bacteria. By varying the influent substrate concentrations and hydraulic retention times (HRT), the volumetric loading rate (VLR) of 55.64 kg-COD/m(3)/day seemed to be optimum for this enriched culture for fermentative hydrogen production from lactate and acetate. The results of batch experiments confirmed that the enriched culture tended to fulfill the e(-) equiv requirement for cell growth at a lower VLR condition (21.77 kg-COD/m(3)/day), while it could largely distribute the e(-) equiv for hydrogen production at a higher VLR condition. However, a maximum lactate/acetate concentration allowed for enriching this culture existed, especially at a lower HRT condition in which wash-out can be an issue for this enriched culture. Finally, the results of cloning and sequencing indicated that Clostridium tyrobutyricum was considered the major hydrogen-producing bacteria in the CSTR fed with lactate and acetate. PMID:22318084

Wu, Chao-Wei; Whang, Liang-Ming; Cheng, Hai-Hsuan; Chan, Kan-Chi

2012-01-05

426

Process for the preparation of vinyl acetate  

DOEpatents

This invention pertains to the preparation of vinyl acetate by contacting within a contact zone a mixture of ketene and acetaldehyde with an acid catalyst at about one bar pressure and between about 85.degree. and 200.degree. C. and removing the reaction products from the contact zone.

Tustin, Gerald Charles (Kingsport, TN); Zoeller, Joseph Robert (Kingsport, TN); Depew, Leslie Sharon (Kingsport, TN)

1998-01-01

427

Thermal Properties of Poly(vinyl chloride-co-vinyl acetate-co-2-hydroxypropyl acrylate) (PVVH) Polymer and Its Application in ZnO Based Nanogenerators  

NASA Astrophysics Data System (ADS)

A novel piezoelectricity based nano energy conversion device using vertically aligned ZnO nanowires/PVVH matrix as the working unit is proposed. Thermal energy is converted to electricity via the interaction of the PVVH polymer and ZnO nanowires. The thermal properties of PVVH are studied using Raman spectroscopy under different temperatures. The results show that the structure of PVVH is sensitive to fluctuations of the environmental temperatures. With the increasing temperature, PVVH tends to be crystallized and stress can be developed inside the polymer. The stress is responsible for the deformation and voltage generation of the ZnO nanowires.

Zhang, Lei; Yang, Jun-He; Wang, Xian-Ying; He, Xing; Zhao, Bin; Tang, Zhi-Hong; Yang, Guang-Zhi; Qiu, Han-Xun

2011-01-01

428

Phenyl Acetate Preparation from Phenol and Acetic Acid: Reassessment of a Common Textbook Misconception.  

ERIC Educational Resources Information Center

|Reassesses a common textbook misconception that "...phenols cannot be esterified directly." Results of experiments are discussed and data tables provided of an effective method for the direct preparation of phenyl acetate. (CS)|

Hocking, M. B.

1980-01-01

429

Polyvinyl alcohol-polyvinyl pyrrolidone thin films provide local short-term release of anti-inflammatory agents post spinal cord injury.  

PubMed

Spinal cord injury (SCI) triggers a large inflammatory response that results in exacerbated tissue damage. Locally delivering anti-inflammatory drugs could mitigate this secondary wave of degeneration. The mitogen-activated protein kinase family members p38 and c-Jun N-terminal kinase (JNK) play important roles in the inflammatory response and cell death. We propose that the use of polymer thin films, made of polyvinyl alcohol and polyvinyl pyrrolidone blends (PVA-PVP), can be used to provide local release of inhibitors to p38 and JNK post-SCI. Release studies performed in vitro confirmed the inhibitors could be released from the film for up to 7 days. The thin film was also tested for its surgical feasibility using a cervical contusion model of SCI in adult female rats. Films with or without the inhibitors were placed subdurally over the injury site immediately following SCI. Animals were sacrificed 5 days post-SCI and spinal cord tissue above and below the injury site was harvested. Additionally, films were removed for analysis. Scanning electron microscopy confirmed the anti-fouling properties of the PVA-PVP film. Tissue histology confirmed that the films themselves did not generate a large immune response, but they did compress the tissue slightly at its placement above the injury site. Finally, quantitative Western blot analysis determined the films loaded with p38 and JNK inhibitors delivered bioactive agents to the injury site and resulted in a significantly decreased amount of pro-cell death proteins. These data indicate that PVA-PVP films can be used to effectively deliver drugs to a SCI site. PMID:22821814

Comolli, Noelle; Donaldson, Olivia; Grantier, Nathan; Zhukareva, Victoria; Tom, Veronica J

2012-07-23

430

Conducting polymer blends: Polypyrrole and polythiophene blends with polystyrene, polycarbonate resin, poly(vinyl alcohol) and poly(vinyl methyl ketone)  

SciTech Connect

Various aromatic compounds can be polymerized by electrochemical oxidation in solution containing a supporting electrolyte. Most studies have been devoted to polypyrrole and polythiophene. In situ doping during electrochemical polymerization yields free standing conductive polymer film. One major approach to making conducting polymer blends is electrochemical synthesis after coating the host polymer on a platinum electrode. In the electrolysis of pyrrole or thiophene monomer, using (t-Bu[sub 4]N)BF[sub 4] as supporting electrolyte, and acetonitrile as solvent, monomer can diffuse through the polymer film, to produce a polypyrrole or polythiophene blend in the film. Doping occurs along with polymerization to form a conducting polymer alloy. The strongest molecular interaction in polymers, and one that is central to phase behavior, is hydrogen bonding. This mixing at the molecular level enhances the degree of miscibility between two polymers and results in macroscopic properties indicative of single phase behavior. In this dissertation, the authors describes the syntheses of conducting polymer blends: polypyrrole and polythiophene blends with polystyrene, poly(bisphenol-A-carbonate), polyvinyl alcohol and poly(vinyl methyl ketone). The syntheses are performed both electrochemically and chemically. Characterization of these blends was carried out by Fourier Transform Infrared spectroscopy, Differential Scanning Calorimetry, Thermogravimetric Analysis, Scanning Electron Microscopy, and X-ray diffraction. Percolating threshold conductivities occur from 7% to 20% for different polymer blends. The low threshold conductivity is attributed to blend homogeneity enhanced by hydrogen bonding between the carbonyl group in the insulating polymer and the N-H group in polypyrrole. Thermal stability, environmental stability, mechanical properties, crystallinity and morphological structure are also discussed. The authors have also engaged in the polymerization of imidazoles.

Wang, H.L.

1992-01-01

431

Polymer coating of paramagnetic particulates for in vivo oxygen-sensing applications  

PubMed Central

Crystalline lithium phthalocyanine (LiPc) can be used to sense oxygen. To enhance biocompatibility/stability of LiPc, we encapsulated LiPc in Teflon AF (TAF), cellulose acetate (CA), and polyvinyl acetate (PVAc) (TAF, previously used to encapsulate LiPc, was a comparator). We identified water-miscible solvents that don’t dissolve LiPc crystals, but are solvents for the polymers, and encapsulated crystals by solvent evaporation. Oxygen sensitivity of films was characterized in vitro and in vivo. Encapsulation did not change LiPc oximetry properties in vitro at anoxic conditions or varying partial pressures of oxygen (pO2). EPR linewidth of encapsulated particles was linear with pO2, responding to pO2 changes quickly and reproducibly for dynamic measurements. Encapsulated LiPc was unaffected by biological oxidoreductants, stable in vivo for four weeks. Oximetry, stability and biocompatibility properties of LiPc films were comparable, but both CA and PVAc films are cheaper, and easier to fabricate and handle than TAF films, making them superior.

Eteshola, Edward; Pandian, Ramasamy P.; Kuppusamy, Periannan

2009-01-01

432

Polymer coating of paramagnetic particulates for in vivo oxygen-sensing applications.  

PubMed

Crystalline lithium phthalocyanine (LiPc) can be used to sense oxygen. To enhance biocompatibility/stability of LiPc, we encapsulated LiPc in Teflon AF (TAF), cellulose acetate (CA), and polyvinyl acetate (PVAc) (TAF, previously used to encapsulate LiPc, was a comparator). We identified water-miscible solvents that don't dissolve LiPc crystals, but are solvents for the polymers, and encapsulated crystals by solvent evaporation. Oxygen sensitivity of films was characterized in vitro and in vivo. Encapsulation did not change LiPc oximetry properties in vitro at anoxic conditions or varying partial pressures of oxygen (pO2). EPR linewidth of encapsulated particles was linear with pO2, responding to pO2 changes quickly and reproducibly for dynamic measurements. Encapsulated LiPc was unaffected by biological oxidoreductants, stable in vivo for four weeks. Oximetry, stability and biocompatibility properties of LiPc films were comparable, but both CA and PVAc films are cheaper, and easier to fabricate and handle than TAF films, making them superior. PMID:19083100

Eteshola, Edward; Pandian, Ramasamy P; Lee, Stephen C; Kuppusamy, Periannan

2009-04-01

433

40 CFR Table 2 to Subpart B of... - MON Source Categories  

Code of Federal Regulations, 2013 CFR

...Vinylidene Chloride Production. Polymethyl Methacrylate Resins Production. Polyvinyl Acetate Emulsions Production. Polyvinyl Alcohol Production. Polyvinyl Butyral Production. Ammonium Sulfate Production-Caprolactam...

2013-07-01

434

Nasal pungency, odor, and eye irritation thresholds for homologous acetates.  

PubMed

We measured detection thresholds for nasal pungency (in anosmics), odor (in normosmics) and eye irritation employing a homologous series of acetates: methyl through octyl acetate, decyl and dodecyl acetate. All anosmics reliably detected the series up to heptyl acetate. Only the anosmics without smell since birth (congenital) reliably detected octyl acetate, and only one congenital anosmic detected decyl and dodecyl acetate. Anosmics who lost smell from head trauma proved to be selectively less sensitive. As expected, odor thresholds lay well below pungency thresholds. Eye irritation thresholds for selected acetates came close to nasal pungency thresholds. All three types of thresholds decreased logarithmically with carbon chain length, as previously seen with homologous alcohols and as seen in narcotic and toxic phenomena. Results imply that nasal pungency for these stimuli rests upon a physical, rather than chemical, interaction with susceptible mucosal structures. When expressed as thermodynamic activity, nasal pungency thresholds remain remarkably constant within and across the homologous series of acetates and alcohols. PMID:1763117

Cometto-Muñiz, J E; Cain, W S

1991-08-01

435

21 CFR 582.5892 - a-Tocopherol acetate.  

Code of Federal Regulations, 2013 CFR

...AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5892 a -Tocopherol acetate. (a) Product. a -Tocopherol acetate....

2013-04-01

436

Draft Guidance on Calcium Acetate Active ingredient: Calcium ...  

Center for Drug Evaluation (CDER)

Text VersionPage 1. Contains Nonbinding Recommendations Draft Guidance on Calcium Acetate ... Active ingredient: Calcium Acetate Form/Route: Tablets/Oral ... More results from www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation

437

Studies on an acetate-fermenting strain of Methanosarcina.  

PubMed Central

An acetate-fermenting strain of Methanosarcina was isolated from an acetate enrichment culture inoculated with anaerobic sludge from a waste treatment digestor. In pure culture, this organism fermented acetate in the absence of added hydrogen at rates comparable in magnitude to those found in digestor systems. This rate was significantly higher than previously obtained for pure cultures of this genus. Mineral components of yeast extract were highly stimulatory for cultures growing on methanol. Comparable stimulation was not observed for cultures growing on acetate. Labeling studies indicated that acetate was converted to methane and CO2 as predicted by previous studies on mixed cultures. Total oxidation or reduction of acetate was not the mechanism of conversion of acetate to methane by the pure culture. The ability of this strain to form colonies or to produce methane from acetate was apparently influenced by the choice of substrate and conditions used for growing the inoculum. Images

Mah, R A; Smith, M R; Baresi, L

1978-01-01

438

Preparation and Characterization of Palm Leaf Incorporated Polyvinyl Alcohol Bio Composites  

NASA Astrophysics Data System (ADS)

The Bio Composites of palm leaf (PL) incorporated polyvinyl alcohol (PVA) has been prepared using solution cast technique. Structural and microhardness properties of pure PVA and PL filled PVA Bio Composites has been determined by using FTIR and Vicker's indentation techniquque respectively. The FTIR analysis reveals the presence of PL moieties in PVA, which indicates the good compatibility between PL and PVA. The values of microhardness increases in all composition of PL incorporated PVA films as compared to the pure PVA. This increment in the microhardness is attributed to the excellent binding of PL into PVA.

Patel, Arunendra Kumar; Bajpai, Rakesh; Keller, J. M.; Saha, Abhijit

2011-12-01

439

Monitoring of temperature fatigue failure mechanism for polyvinyl alcohol fiber concrete using acoustic emission sensors.  

PubMed

The applicability of acoustic emission (AE) techniques to monitor the mechanism of evolution of polyvinyl alcohol (PVA) fiber concrete damage under temperature fatigue loading is investigated. Using the temperature fatigue test, real-time AE monitoring data of PVA fiber concrete is achieved. Based on the AE signal characteristics of the whole test process and comparison of AE signals of PVA fiber concretes with different fiber contents, the damage evolution process of PVA fiber concrete is analyzed. Finally, a qualitative evaluation of the damage degree is obtained using the kurtosis index and b-value of AE characteristic parameters. The results obtained using both methods are discussed. PMID:23012555

Li, Dongsheng; Cao, Hai

2012-07-11

440

Poly(vinyl chloride)-based macrocyclic membrane sensors for magnesium  

Microsoft Academic Search

Poly(vinyl chloride)-based membranes of macrocycles 4,11-dimethyl-2,4,9,11-tetraethyl-1,5,8,12-tetraaza cyclotetradeca-1,8-diene (I) and 4,11-dioxa-2,9-dimethyl-1,5,8,12-tetraaza cyclotetradeca-1,8-diene (II) with sodium tetraphenyl borate (STB) as an anion excluder and dibutyl phthalate (DBP), dioctyl phthalate (DOP), dibutylbutyl phosphonate (DBBP) and 1-chloronaphthalene (CN) as plasticizing solvent mediators were prepared and investigated as magnesium selective electrodes. The best performance was observed having the composition (II)–PVC–STB–DBP in the ratio 2:10:1:7, which

Seema Baniwal; S. Chandra; A. Panwar; A. K. Singh

1999-01-01

441

Flexible polyvinyl chloride neutron guides for transporting ultracold and very cold neutrons  

SciTech Connect

The transmission of ultracold neutrons (UCNs) through flexible polyvinyl chloride (PVC) tubes with lengths of up to 3 m and an internal diameter of 6-8 mm has been studied. High UCN transmission is found even for arbitrarily bent tubes (single bend, double bend, triple bend, figure eight, etc.). The transmission can be improved significantly by coating the inner surface of the tube with a thin layer of liquid fluorine polymer. The prospects of these neutron guides in fundamental and applied research are discussed.

Arzumanov, S. S., E-mail: sarzumanov@yandex.ru; Bondarenko, L. N. [Russian Research Center Kurchatov Institute (Russian Federation); Geltenbort, P. [Institut Laue-Langevin (France); Morozov, V. I. [Russian Research Center Kurchatov Institute (Russian Federation); Nesvizhevsky, V. V. [Institut Laue-Langevin (France); Panin, Yu. N.; Strepetov, A. N.; Chuvilin, D. Yu. [Russian Research Center Kurchatov Institute (Russian Federation)

2011-12-15

442

Role of metal oxides in the thermal degradation of poly(vinyl chloride)  

SciTech Connect

Thermal degradation of poly(vinyl chloride) has been studied in the presence of metal oxides by a thermogravimetric method. It follows a two-step mechanism. In the first step chlorine free radical is formed as in the case of pure PVC, and in the second step chlorine free radical replaces oxygen from metal oxide to form metal chloride and oxygen free radical. Subsequently, the oxygen free radical abstracts hydrogen from PVC. Formation of metal chloride is the rate-controlling step. The metal chlorides formed during the thermal degradation either volatilize or decompose simultaneously to lower metallic chlorides depending on the boiling point or the volatilization temperature.

Gupta, M.C.; Viswanath, S.G. [Nagpur Univ. (India)

1998-07-01

443

Cross-linked polyvinyl alcohols and oil reservoir permeability control therewith  

SciTech Connect

This patent describes an improved method of recovering oil under steam flooding conditions from an oil-bearing subterranean formation penetrated by an injection well and a production well, in which an aqueous fluid is injected into the formation through the injection well to displace oil to the production well. The improvement comprising employing, in at least a portion of the aqueous fluid injected into the formation, a cross-linked polymer obtained by cross-linking polyvinyl alcohol with a cross-linking agent which is a mixture of a phenolic component and an aldehyde or a mixture of a naphtholic component and an aldehyde.

Hoskin, D.H.; Shu, P.

1990-01-30

444

Suppression of instability by double ablation in tungsten doped polyvinyl alcohol foils  

NASA Astrophysics Data System (ADS)

In Inertial fusion Energy (IFE) research stable acceleration of fusion targets is a significant problem due to hydrodynamic instabilities. This paper presents the results of the experiments done to investigate the effects of doping 20% of Tungsten (W) (by weight) in Polyvinyl Alcohol (PVA) polymer foils for suppression of instability during laser ablative acceleration. A 20J, 1.060?m, 900ps, Nd: Glass laser system with a focusable intensity of 3 to 9.6×1013W/cm2 was used in the experiment. It is observed that the doped PVA targets yielded stable and enhanced foil acceleration as compared to the undoped PVA foils.

Peedikakkandy, Leshma; Chaurasia, S.

2012-07-01

445

Near ultraviolet photodetector fabricated from polyvinyl-alcohol coated In2O3 nanoparticles  

NASA Astrophysics Data System (ADS)

A near ultraviolet (UV) photodetector is fabricated from colloidal In2O3 nanoparticles coated with polyvinyl-alcohol (PVA). The device exhibits lower dark current and higher responsivity compared with a photodetector fabricated from uncoated In2O3 nanoparticles. The rise and fall time of the PVA coated photodetector is about 500 s and 1600 s, respectively, one half of the uncoated device. The faster response time of the PVA enhanced photodetector is due to surface passivation which reduces the surface defects while enhancing desorption of oxygen from the nanoparticle surface, thus increasing free carrier concentration.

Shao, Dali; Qin, Liqiao; Sawyer, Shayla

2012-11-01

446

Molecular vibrational dynamics in polyvinyl alcohol studied by femtosecond coherent anti-stokes Raman spectroscopy  

NASA Astrophysics Data System (ADS)

We have performed femtosecond time-resolved coherent anti-stokes Raman spectroscopy (CARS) to study the vibrational dynamics in polyvinyl alcohol (PVA) film. We observed femtosecond coherent vibrational relaxation and CARS signal beats in PVA at room temperature. We found that the coherent vibrational relaxation of anti-symmetric CH2 stretching modes in PVA is faster than that of symmetric modes, probably due to faster vibrational energy transfer. The coherent vibrational relaxation of OH stretching modes was observed to be slower than that of CH2 modes, because OH stretching modes have less resonant energy transfer rate compared to CH2 modes.

Kozai, T.; Yamashita, S.; Hirochi, K.; Miyagawa, H.; Tsurumachi, N.; Koshiba, S.; Nakanishi, S.; Itoh, H.

2012-11-01

447

Dyed-polyvinyl alcohol films: molecular weight and hydrolysis degree influence on optical recording  

NASA Astrophysics Data System (ADS)

An analysis of different polyvinyl alcohol films dyed with Malachite Green is presented. Absorbance and diffraction efficiency of holographic gratings are compared, taking as a parameter the molecular weight and hydrolysis degree of the polymer. It is observed that, using the same dye concentration, the absorption coefficient of the films increases as the molecular weight increases. The absorbance of these plates can be modified when exposed to UV light. In addition, it is found that for holographic recording there is an optimal dye-polymer system film.

Solano, Cristina; Martinez-Ponce, Geminiano; Castañeda, Carlos

2006-07-01

448

A high-dose dosimeter-based polyvinyl chloride dyed with malachite green  

NASA Astrophysics Data System (ADS)

Polyvinyl chloride (PVC) film dyed with malachite green was studied for high-dose radiation dosimetry using visible spectrophotometry. A linear relationship between the relative absorbance and the absorbed dose at the wavelength 628 nm in the range of 0 125 kGy was found. The effect of dose rate, irradiation temperature, film thickness and dye intensity were found not to influence the response. The effects of shelf life and the post-irradiation storage in darkness and indirect daylight conditions on dosimetry performance were discussed.

Kattan, M.; Daher, Y.; Alkassiri, H.

2007-07-01

449

Thermo-responsive devices using poly(vinyl methyl ether) hydrogels  

SciTech Connect

Aqueous solution of poly(vinyl methyl ether) (PVME) shows phase transition around 38 C. PVME hydrogel cross-linked by gamma-ray irradiation is also a thermally responsive hydrogel and undergoes volume change at the same temperature; it swells below and shrinks above 38 C. PVME hydrogel prepared near phase transition temperature has heterogeneous and macroporous structure. The volume change of the macroporous hydrogel takes place rapidly with changing temperature. An attempt has been made to develop thermally activated chemomechanical devices such as an artificial muscle model, an automatic separation system, an artificial finger model, and a photo-responsive device.

Kishi, R.; Ichijo, H.; Hirasa, O. [National Inst of Materials and Chemical Research, Ibaraki (Japan)

1993-10-01

450

Water vapor barrier property of organic–silica nanocomposite derived from perhydropolysilazane on polyvinyl alcohol substrate  

Microsoft Academic Search

Poly(vinyl alcohol) membrane was coated with organic–silica nanocomposite derived from perhydropolysilazane. For organic composite part, polystyrene-block-poly(4-vinyl phenol) [SP], poly(tert-butyl acrylate-co-2-hydroxyethyl methacrylate) [BA] and poly(butyl methacrylate-co-2-hydroxyethyl methacrylate) [BMA] were used. Water vapor barrier property of coat membrane was measured at relative humidity=96% by a cup method. The coat films of nanocomposites with SP–silica and BA–silica showed better water vapor barrier property

Reiko Saito; Takayoshi Hosoya

2008-01-01

451

Diffusion studies of FeCl3 doped poly(vinyl alcohol) films  

NASA Astrophysics Data System (ADS)

Poly(vinyl alcohol) (PVA) films doped with various mass fractions of FeCl3 were prepared by solution casting method. The diffusion studies of FeCl3 doped PVA were carried out using distilled water, rain water and sea water. The diffusion coefficient and penetration rate decreases with increasing FeCl3 concentration, which is explained by Fick's law of diffusion. The crosslinking density Ve, is calculated based on Flory-Huggins theory. The crosslinking density increases with increase in FeCl3 dopant concentration.

Sheela, T.; Ravindrachary, V.; Bhajantri, R. F.; Ismayil; Rathod, Sunil; Praveena, S. D.

2012-06-01

452

Gold-catalyzed cyclization of allenyl acetal derivatives.  

PubMed

The gold-catalyzed transformation of allenyl acetals into 5-alkylidenecyclopent-2-en-1-ones is described. The outcome of our deuterium labeling experiments supports a 1,4-hydride shift of the resulting allyl cationic intermediates because a complete deuterium transfer is observed. We tested the reaction on various acetal substrates bearing a propargyl acetate, giving 4-methoxy-5-alkylidenecyclopent-2-en-1-ones 4 via a degradation of the acetate group at the allyl cation intermediate. PMID:24062838

Vasu, Dhananjayan; Pawar, Samir Kundlik; Liu, Rai-Shung

2013-08-27

453

Gold-catalyzed cyclization of allenyl acetal derivatives  

PubMed Central

Summary The gold-catalyzed transformation of allenyl acetals into 5-alkylidenecyclopent-2-en-1-ones is described. The outcome of our deuterium labeling experiments supports a 1,4-hydride shift of the resulting allyl cationic intermediates because a complete deuterium transfer is observed. We tested the reaction on various acetal substrates bearing a propargyl acetate, giving 4-methoxy-5-alkylidenecyclopent-2-en-1-ones 4 via a degradation of the acetate group at the allyl cation intermediate.

Vasu, Dhananjayan; Pawar, Samir Kundlik

2013-01-01

454

Contribution of acetate to butyrate formation by human faecal bacteria  

Microsoft Academic Search

Acetate is normally regarded as an endproduct of anaerobic fermentation, but butyrate-producing bacteria found in the human colon can be net utilisers of acetate. The butyrate formed provides a fuel for epithelial cells of the large intestine and influences colonic health. (1-13C)Acetate was used to investigate the contribution of exogenous acetate to butyrate formation. Faecalibacterium prausnitzii and Roseburia spp. grown

Sylvia H. Duncan; Grietje Holtrop; Gerald E. Lobley; A. Graham Calder; Colin S. Stewart; Harry J. Flint

2004-01-01

455

Effect of trimethylamine on acetate utilization by Methanosarcina barkeri  

Microsoft Academic Search

During growth of Methanosarcina barkeri strain Fusaro on a mixture of trimethylamine and acetate, methane production and acetate consumption were biphasic. In the first phase trimethylamine (33 mmol x l-1) was depleted and some acetate (11–14 from 50 mmol x l-1) was metabolized simultaneously. In the second phase the remaining acetate was cleaved stoichiometrically into CH4 and CO2. Kinetic experiments

Michael Blaut; Gerhard Gottschalk

1982-01-01

456

Separating acetic acid from furol (furfural) by electrodialysis method  

SciTech Connect

Furfural production by hydrolysis of fibrous plant materials is accompanied by formation of acetic acid in amounts depending on the material used. The amount of acetic formed in the hydrolysis of the fruit shell of oil-tea camellia (Camellia oleosa) (an oilseed-bearing tree) is equal to the amount of furfural. The acetic acid can be separated from the furfural and concentrated to 10% by electrodialysis. A smaller amount of furfural is separated with acetic acid.

Guan, S.F.; Li, C.S. Ye, S.T.; Shen, S.Y.; Wang, Y.T.; Yu, S.H.

1981-01-01

457

Interferon beta and glatiramer acetate therapy.  

PubMed

Interferon beta and glatiramer acetate have been mainstays of treatment in relapsingremitting multiple sclerosis for two decades. Remarkable advances in our understanding of immune function and dysfunction as well as increasingly sophisticated clinical trial design have stemmed from efforts to better understand these drugs. In this chapter, we review the history of their development and elaborate on known and theorized mechanisms of action. We describe the pivotal clinical trials that have led to their widespread use. We evaluate the clinical use of the drugs including tolerability, side effects, and efficacy measures. Finally, we look to the future of interferon beta and glatiramer acetate in the context of an ever growing armamentarium of treatments for relapsing remitting multiple sclerosis. PMID:23264098

McGraw, Corey A; Lublin, Fred D

2013-01-01

458

Assessment Guidelines for Managing Cellulose Acetate Collections  

NSDL National Science Digital Library

Photographic negatives, motion picture film, microfilm, and sound recordings produced from the 1930s into the 1950s often used cellulose acetate as the transparent plastic carrier. As anyone who has ever come in contact with it well knows, its strong vinegar-like scent is hard to miss. Unfortunately, over time, the material is prone to deterioration, which eventually renders it unusable. In an effort to help guide libraries in Australia with this problem, the National Library of Australia has created this document. It provides assistance in identification of cellulose acetate (vs. other similar materials) and establishes criteria to assess condition, cultural importance, and use within the library or storage context. The document guides readers through the first step in a strategy for preserving these collections.

2001-01-01

459

36 CFR 1232.24 - Unstable cellulose-acetate film.  

Code of Federal Regulations, 2010 CFR

...Public Property 3 2009-07-01 2009-07-01 false Unstable cellulose-acetate film. 1232.24 Section 1232.24...MANAGEMENT Audiovisual Records Management § 1232.24 Unstable cellulose-acetate film. Cellulose-acetate film,...

2009-07-01

460

Kinetics of Ethyl Acetate Synthesis Catalyzed by Acidic Resins  

ERIC Educational Resources Information Center

|A low-cost experiment to carry out the second-order reversible reaction of acetic acid esterification with ethanol to produce ethyl acetate is presented to illustrate concepts of kinetics and reactor modeling. The reaction is performed in a batch reactor, and the acetic acid concentration is measured by acid-base titration versus time. The…

Antunes, Bruno M.; Cardoso, Simao P.; Silva, Carlos M.; Portugal, Ines

2011-01-01

461

Acetic acid vapor levels associated with facial prosthetics  

SciTech Connect

The use of Silastic Medical Adhesive Type A in the fabrication of facial prostheses may cause health hazards to the patient and the operator because of acetic acid emissions. Caution must be exercised to remove acetic acid vapors from the air and unliberated acetic acid from material applied directly to the skin.

McElroy, T.H.; Guerra, O.N.; Lee, S.A.

1985-01-01

462

21 CFR 582.5933 - Vitamin A acetate.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Vitamin A acetate. 582.5933 Section 582...AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5933 Vitamin A acetate. (a) Product. Vitamin A acetate. (b) Conditions of...

2013-04-01

463

Kinetics of the methanogenic fermentation of acetate. [Methanosarcina barkeri  

SciTech Connect

Inhibition of the fermentation of acetate to methane and carbon dioxide by acetate was analyzed with an acetate-acclimatized sludge and with Methanosarcina barkeri Fusaro under mesophilic conditions. A second-order substrate inhibition model, q{sub CH{sub 4}} = q{sub m}S/(K{sub s} + S + (S{sup 2}/K{sub i})), where S was the concentration of undissociated acetic acid, not ionized acetic acid, could be applicable in both cases. The analysis resulted in substrate saturation constants, K{sub s}, of 4.0 {mu}M for the acclimatized sludge and 104 {mu}M for M. barkeri. The threshold concentrations of undissociated acetic acid when no further acetate utilization was observed were 0.078 {mu}M (pH 7.50) for the acclimatized sludge and 4.43 {mu}M (pH 7.45) for M. barkeri. These kinetic results suggested that the concentration of undissociated acetic acid became a key factor governing the actual threshold acetate concentration for acetate utilization and that the acclimatized sludge in which Methanothrix spp. appeared dominant could utilize acetate better and survive at a lower concentration of undissociated acetic acid than could M. barkeri.

Fukuzaki, Satoshi; Nishio, Naomichi; Nagai, Shiro (Hiroshima Univ. (Japan))

1990-10-01

464

PREPARATION AND PROPERTIES OF WATER-SOLUBLE STARCH ACETATES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Starch acetates of degree of substitution (DS) 0-1.5 were prepared by heating dry corn starch, acetic acid and acetic anhydride in sealed 60 ul vessels at 180 degree C for 5 minutes. These reactions appeared to be homogeneous (clear) and proceeded to completion without added catalyst. Starch aceta...

465

Pathway of acetate assimilation in autotrophic and heterotrophic methanococci.  

PubMed Central

The autotroph Methanococcus maripaludis contained high levels of acetate-coenzyme A ligase, pyruvate synthase, pyruvate, water dikinase, pyruvate carboxylase, and the enzymes of the incomplete reductive tricarboxylic acid cycle. Phosphoenolpyruvate carboxykinase, citrate synthase, and isocitrate dehydrogenase were not detected. In contrast, the heterotroph Methanococcus sp. strain A3 contained acetate kinase, and acetate coenzyme A ligase was virtually absent.

Shieh, J S; Whitman, W B

1987-01-01

466

Pathway of acetate assimilation in autotrophic and heterotrophic methanococci.  

PubMed

The autotroph Methanococcus maripaludis contained high levels of acetate-coenzyme A ligase, pyruvate synthase, pyruvate, water dikinase, pyruvate carboxylase, and the enzymes of the incomplete reductive tricarboxylic acid cycle. Phosphoenolpyruvate carboxykinase, citrate synthase, and isocitrate dehydrogenase were not detected. In contrast, the heterotroph Methanococcus sp. strain A3 contained acetate kinase, and acetate coenzyme A ligase was virtually absent. PMID:3667534

Shieh, J S; Whitman, W B

1987-11-01

467

Preparation and selective hydrolysis of acetal esters  

Microsoft Academic Search

and Summary  Medium chain length aldehydic acids and esters (C8-C13) were synthesized by ozonolysis of readily available cyclic and straight chain alkenoate esters followed by rearrangement\\u000a or reduction of the ozonide. The acetal esters, prepared by reaction of the aldehydic acids with CH3OH-HC1, were characterized by gas liquid chromatography, proton magnetic resonance, carbon magnetic resonance, thin layer\\u000a chromatography, and infrared analysis.

R. O. Adlof; W. E. Neff; E. A. Emken; E. H. Pryde

1977-01-01

468

Effect of ethyl acetate on carbohydrate components and crystalline structure of pulp produced in aqueous acetic acid pulping  

Microsoft Academic Search

The aim of this study was to investigate the changes in carbohydrate components and the crystalline structure in hemp bast\\u000a fibers by adding ethyl acetate to acetic acid\\/water pulping processes. It was found that ethyl acetate added to acetic acid\\/water\\u000a process had a positive effect on yield, viscosity and carbohydrate components in pulp. It was assumed that the delignification\\u000a ratio

Esat Gümü?kaya; Mustafa Usta; Mualla Balaban Uçar

2009-01-01

469

Interaction of gloves and rubber dam with a poly(vinyl siloxane) impression material: a screening test.  

PubMed

Polymerization inhibition of poly(vinyl siloxane) impression materials has been reported with the use of latex gloves. This study evaluated the effect on polymerization of a poly(vinyl siloxane) impression material in both direct and indirect contact with 25 brands of latex gloves, two brands of vinyl gloves, and two weights of rubber dam. Use of all but one of the latex products (96%) resulted in inhibition of polymerization with direct contact. Forty percent of the latex gloves tested inhibited polymerization with indirect contact. The vinyl gloves tested had no effect on polymerization. The implications of inhibited polymerization were discussed. PMID:2638846

Kahn, R L; Donovan, T E; Chee, W W

470

A quantitative histochemical study of 5?-nucleotidase activity in rat liver using the lead salt method and polyvinyl alcohol  

Microsoft Academic Search

Summary  5-Nucleotidase (EC 3.1.3.5) activity was demonstrated in cryostat sections of rat liver using the Wachstein—Meisel medium and polyvinyl alcohol as tissue stabilizer. Optimum activity was obtained using an incubation medium containing 5mm AMP, 10mm magnesium chloride, 7.2mm lead nitrate, 0.1m Tris—maleate buffer, pH 7.2, and 17% (w\\/v) polyvinyl alcohol (Sigma, type III). The activity was localized at the bile canalicular

Wilma M. Frederiks; Frans Marx

1988-01-01

471

Isothermal vapor-liquid equilibria for mixtures of methyl tert-butyl ether, methyl acetate, and ethyl acetate  

Microsoft Academic Search

A static apparatus was applied to measure isothermal vapor-liquid equilibrium (VLE) data for binary and ternary mixtures composed of methyl tert-butyl ether (MTBE), methyl acetate, and ethyl acetate at temperatures from 353 K to 373 K. Maximum pressure azeotropes were exhibited in the MTBE + methyl acetate system. All the binary data passed thermodynamic consistency tests. Data reduction was made

Ming-Jer Lee; Chien-Chih Hsiao; Ho-mu Lin

1997-01-01

472

Elution behavior of oligomers on a polyvinyl alcohol gel column with chloroform, methanol, and their mixtures  

SciTech Connect

Elution phenomena of size exclusion chromatography (SEC) plus superimposed adsorption effects for oligostyrenes, epoxy resins, methylated melamine-formaldehyde resin prepolymers, p-cresol-formaldehyde resin prepolymers, and phenol-formaldehyde resin prepolymers were investigated. SEC and superimposed adsorption effects could be elucidated from a concept of solubility parameter. Minimum retention volumes of these obligomers were obtained with the mobile phases of chloroform/methanol, 80/20 or 60/40 (v/v), and separation was expected to be mostly performed by SEC. The solubility parameter of polyvinyl alcohol gels was estimated to be between 21 and 23 from the above results. Elution for normal phase chromatography was in the order of increasing molecular weight and that for reversed-phase chromatography was in the order of decreasing molecular weight. These are reversed phenomena to those for low-molecular weigh compounds. Solubility of sample solutes to mobile phase must be considered. Methanol mobile phase-polyvinyl alcohol gel system might be exception.

Mori, S. (Dept. of Industrial Chemistry, Faculty of Engineering, Mie Univ., Tsu, Mie 514 (JP))

1988-01-01

473

Properties of novel polyvinyl alcohol/cellulose nanocrystals/silver nanoparticles blend membranes.  

PubMed

Novel polyvinyl alcohol (PVA) blend membranes containing cellulose nanocrystals (CNs) and silver nanoparticles (AgNPs) were prepared via a simple method. CNs were prepared by sulfuric acid treatment of microcrystalline cellulose. AgNO3 aqueous solution mixed with the CNs aqueous suspension and was reduced by NaBH4 at room temperature. Purified CNs/AgNPs nanocomposites as functional fillers mixed with polyvinyl alcohol to prepare blend membrane. The morphology, mechanical properties, and antibacterial activities of PVA/CNs/AgNPs composite films were investigated. The PVA/CNs/AgNPs composite films were stable and homogeneous. The tensile strength of PVA was increased from 57.02MPa to 81.21MPa when filled with CNs/AgNPs. Antibacterial ratio of PVA/CNs/AgNPs composite against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus was 96.9% and 88.2%, respectively. The CNs/AgNPs nanocomposites could be applied as bi-functional nanofillers within PVA to improve the mechanical properties and antibacterial activities. PMID:24053842

Xu, Xu; Yang, Yi-Qin; Xing, Ying-Ying; Yang, Jiu-Fang; Wang, Shi-Fa

2013-08-07

474

Band gap energy and optical transitions in polyenes formed by thermal decomposition of polyvinyl alcohol  

NASA Astrophysics Data System (ADS)

The band gap of the ensemble of oligoene clusters formed by thermocatalytic decomposition of polyvinyl alcohol is parametrized using optical absorption spectra. A band gap energy of E gm =1.53 ± 0.02 eV at the end of an infinite polyene chain is found by extrapolating the energies of ? ? ?* transitions in clusters with a number of double bonds varying from 4 to 12. This value is close to the band gap of trans-polyacetylene and the lower bound for the Tauc energy E gT =1.50 eV, which characterizes the minimum interband transition energy. E gT is essentially independent of the concentration of oligoene clusters, which is determined by the concentration of the AlCl3 thermal decomposition catalyst. The Urbach energy determined from the long wavelength edge of the spectrum falls from 2.21 to 0.66 eV as the AlCl3 concentration is raised from 11.1 to 41.7 mmol per mol of polyvinyl alcohol structural units.

Kulak, A. I.; Bondarava, G. V.; Shchurevich, O. A.

2013-07-01

475

Influence of heparin coating on in vitro bacterial adherence to poly(vinyl chloride) segments.  

PubMed

End-point attached, covalently bound heparin has been shown to be effective in preventing activation of the coagulation cascade by biomaterials. Data concerning its possible influence on bacterial attachment and resistance to biomaterial-associated infection are, so far, lacking. In the present work, the in vitro adherence of Staphylococcus aureus, Staphylococcus epidermidis and Escherichia coli, one isolate of each species, to plain poly(vinyl chloride) (plain PVC) and heparin coated poly(vinyl chloride) (EPA-PVC) segments was compared. Also, the influence of precoating the segments with human normal plasma for 2 h was studied. 35S-Methionine was used to radiolabel bacteria. The segments were exposed to bacterial suspensions of approximately 10(7) colony forming units (CFU) per milliliter at 37 degrees C for 0.5-6 h. Following repeated washing in phosphate buffered saline (PBS), radioactivity associated with the segments was measured. Plain PVC as compared to EPA-PVC bound significantly more cells of all three tested species. Plasma precoating significantly decreased adherence of the tested species to plain PVC but did not affect the binding to EPA-PVC. However, after precoating with human plasma, EPA-PVC compared to plain PVC showed a higher binding of S. aureus which might possibly be due to bridging effects of fibronectin or other plasma proteins, interacting with S. aureus. PMID:9342649

Zdanowski, Z; Koul, B; Hallberg, E; Schalén, C

1997-01-01

476

Acute health effects among firefighters exposed to a polyvinyl chloride (PVC) fire  

SciTech Connect

Firefighters are frequently being called on to fight fires that are chemical in nature. In the aftermath of a chemical fire in Plainfield, New Jersey on March 20-21, 1985, the authors conducted a retrospective cohort study which surveyed 80 firefighters exposed to burning polyvinyl chloride (PVC) as well as 15 nonexposed firefighter subjects. By means of an 81-item symptom checklist, exposed firefighters reported more frequent and severe symptoms at 5-6 weeks post incident. This was true for a total symptomatology score as well as 19 individual items. Some of the items with an elevated risk were consistent with exposure to hydrogen chloride, the main pyrolysis product of polyvinyl chloride. Other items with an elevated risk appeared to be related to smoke inhalation while others seemed psychosocial in nature. Analyses conducted within the exposed firefighter group showed that fighting the fire the first day, being a truckman, and residence within 1 mile (1.6 km) of the firehouse were significant risk factors for high total symptom scores. These risk factors may have been associated with level or duration of exposure to the toxic substances produced during the fire.

Markowitz, J.S.; Gutterman, E.M. (New York State Psychiatric Institute (USA)); Schwartz, S.; Link, B.; Gorman, S.M. (Columbia Univ., New York (USA))

1989-05-01

477

Lidocaine stability in cardioplegic solution stored in glass bottles and polyvinyl chloride bags.  

PubMed

The stability of lidocaine hydrochloride in buffered cardioplegic solutions stored in glass and polyvinyl chloride bags was studied. Concentrations of lidocaine (incorporated as the hydrochloride salt) were measured in buffered cardioplegic solutions containing potassium chloride, sodium bicarbonate, dextrose, and sodium chloride. Solutions were stored at 22 +/- 2 degrees C and 4 degrees C in glass bottles and 500-ml and 250-ml polyvinyl chloride (PVC) containers; some 250-ml PVC bags were underfilled to study the effects of varying surface area-volume ratios. Lidocaine concentrations were measured using a homogeneous enzyme immunoassay (EMIT, Syva Corporation) on days 0, 1, 2, 7, and 21. Lidocaine concentrations decreased significantly in all PVC bags stored at 22 degrees C and in underfilled PVC bags stored at 4 degrees C. Lidocaine loss in PVC bags appeared to result from sorption. It is concluded that lidocaine is stable in cardioplegic solutions when these are refrigerated and stored in glass containers or filled large-volume PVC bags for 21 days. PMID:6823998

Lackner, T E; Baldus, D; Butler, C D; Amyx, C; Kessler, G

1983-01-01

478

Recovery of very dilute acetic acid using ion exchange  

SciTech Connect

Acetic and related acids occur in many industrial wastewaters, often mixed with several other classes of organic compounds. Acetic acid can be recovered from 1% solutions using weakly basic ion exchange resins. The acid is adsorbed by the free-base form of the resin, which can then be eluted using a slurry of lime to give a solution of calcium acetate. This solution could either be evaporated to crystallize calcium acetate or reacted with sulfuric acid to form acetic acid and gypsum. Laboratory tests of the proposed process gave product solutions of 15--20% acetic acid using pure 1% acetic acid as feed. Some measurements using a typical industrial effluent gave similar recoveries and showed that there was no initial fouling of the resins.

Cloete, F.L.D.; Marais, A.P. [Univ. of Stellenbosch (South Africa). Dept. of Chemical Engineering

1995-07-01

479

[Degradation of oxytetracycline with ozonation in acetic acid solvent].  

PubMed

Use acetic acid as the media of ozone degradation of oxytetracycline (OTC), and effects of the initial dosing ratio of ozone/OTC, ozone flow, free radical scavenger, metal ions on the removal rate of OTC were investigated respectively. The results showed that acetic acid had a high ozone stability and solubility. OTC had a high removal rate and degradation rate in acetic acid solution. With the increase of OTC dosage, the removal rate of OTC decreased in acetic acid. Removal rate of OTC was increased distinctly when ozone flow increased properly. It was also observed that free radical scavenger had a significantly negative effect on OTC ozonation degradation in acetic acid. Furthermore the main reactions of OTC ozone oxidation were direct oxidation and indirect oxidation in acetic acid. When Fe3+ and Co2+ were existent in acetic acid, the degradation of OTC was inhibited significantly. PMID:23379161

Li, Shi-Yin; Li, Xiao-Rong; Zhu, Yi-Ping; Zhu, Jiang-Peng; Wang, Guo-Xiang

2012-12-01

480

Calcium Magnesium Acetate at Lower-Production Cost: Production of CMA Deicer from Cheese Whey.  

National Technical Information Service (NTIS)

Calcium magnesium acetate (CMA), a mixture of calcium acetate and magnesium acetate, is used as an environmentally benign roadway deicer. The present commercial CMA deicer made from glacial acetic acid and dolomitic lime or limestone is expensive compared...

H. Zhu S. T. Yang W. Qin Y. Huang Y. L. Huang Z. Jin

1999-01-01

481

Roseovarius sp. strain 217: aerobic taurine dissimilation via acetate kinase and acetate-CoA ligase.  

PubMed

The genome sequence of Roseovarius sp. strain 217 indicated that many pathway enzymes found in other organisms for the degradation of taurine are represented, but that a novel, apparently energy-dependent pathway is involved in the conversion of acetyl phosphate to acetyl CoA. Thus, an ABC transporter for taurine could be postulated, while inducible taurine: pyruvate aminotransferase, alanine dehydrogenase, sulfoacetaldehyde acetyltransferase and sulfite dehydrogenase could be assayed. Whereas phosphate acetyltransferase has been found in other organisms, none was indicated in the genome sequence and no activity was found in cell-free extracts. Instead, acetate kinase was active as was acetate-CoA ligase. PMID:17425660

Baldock, Marijke I; Denger, Karin; Smits, Theo H M; Cook, Alasdair M

2007-04-10

482

Acetate supplementation attenuates lipopolysaccharide-induced neuroinflammation  

PubMed Central

Glyceryl triacetate (GTA), a compound effective at increasing circulating and tissue levels of acetate was used to treat rats subjected to a continual 28 day intra-ventricular infusion of bacterial lipopolysaccharide (LPS). This model produces a neuroinflammatory injury characterized by global neuroglial activation and a decrease in choline acetyltransferase immunoreactivity in the basal forebrain. During the LPS infusion, rats were given a daily treatment of either water or GTA at a dose of 6g/kg by oral gavage. In parallel experiments free-CoA and acetyl-CoA levels were measured in microwave fixed brains and flash frozen heart, liver, kidney and muscle following a single oral dose of GTA. We found that a single oral dose of GTA significantly increased plasma acetate levels by 15 min and remained elevated for up to 4 hr. At 30 min the acetyl-CoA levels in microwave-fixed brain and flash frozen heart and liver were increased at least 2.2-fold. The concentrations of brain acetyl-CoA was significantly increased between 30 and 45 min following treatment and remained elevated for up to 4 hr. The concentration of free-CoA in brain was significantly decreased compared to controls at 240 min. Immunohistochemical and morphological analysis demonstrated that a daily treatment with GTA significantly reduced the percentage of reactive GFAP-positive astrocytes and activated CD11b-positive microglia by 40–50% in rats subjected to LPS-induced neuroinflammation. Further, in rats subjected to neuroinflammation, GTA significantly increased the number of ChAT-positive cells by 40% in the basal forebrain compared to untreated controls. These data suggest that acetate supplementation increases intermediary short chain acetyl-CoA metabolism and that treatment is potentially anti-inflammatory and neuroprotective with regards to attenuating neuroglial activation and increasing ChAT immunoreactivity in this model.

Reisenauer, Chris J.; Bhatt, Dhaval P.; Mitteness, Dane J.; Slanczka, Evan R.; Gienger, Heidi M.; Watt, John A.; Rosenberger, Thad A.

2011-01-01

483

Acetals of lactams and acid amides  

Microsoft Academic Search

A new approach to the synthesis of one-, two-, and three-ring compounds from enamides and enamino ketones was investigated. Thus the reaction of a-cyano-ß-dimethylaminoacrylamide with guanidine gave 2, 4-diamino-5-carbamidopyrimidine, the cyclization of which with dimethylformamide acetal and subsequent hydrolysis gave 2-amino-5,6-dihydro-5-oxopyrimido[4,5-d]pyrimidine. An enamino ketone — 1-benzoyl-2-dimethylamino-2-methylethylene — was subjected to condensation with guanidine, thiourea, and acetamidine, as a result of

O. Ya. Belyaeva; V. G. Granik; R. G. Glushkov; T. F. Vlasova; O. S. Anisimova

1978-01-01

484

4-Meth-oxy-benzamidinium acetate.  

PubMed

The title compound, C8H11N2O(+)·CH3CO2(-), was synthesized by a reaction between 4-meth-oxy-benzamidine (4-amidino-anisole) and acetic acid. In the cation, the amidinium group forms a dihedral angle of 11.65?(17)° with the mean plane of the benzene ring. The ionic components are associated in the crystal via N-H(+)?O(-) hydrogen bonds, resulting in a one-dimensional structure consisting of dimers and catemers and orientated approximately along the c axis. PMID:23468790

Irrera, Simona; Portalone, Gustavo

2012-11-03

485

4-Meth-oxy-benzamidinium acetate  

PubMed Central

The title compound, C8H11N2O+·CH3CO2 ?, was synthesized by a reaction between 4-meth­oxy­benzamidine (4-amidino­anisole) and acetic acid. In the cation, the amidinium group forms a dihedral angle of 11.65?(17)° with the mean plane of the benzene ring. The ionic components are associated in the crystal via N—H+?O? hydrogen bonds, resulting in a one-dimensional structure consisting of dimers and catemers and orientated approximately along the c axis.

Irrera, Simona; Portalone, Gustavo

2012-01-01

486

Simultaneous adsorption of sodium dodecyl sulfate and poly(vinyl pyrrolidone) on titanium dioxide with quaternary ammonium groups  

Microsoft Academic Search

Simultaneous adsorption of sodium dodecyl sulfate (SDS) and poly(vinyl pyrrolidone) (PVP) on titanium dioxide with quaternary ammonium groups (XNm, where m is the carbon number of the alkyl chain, 8 and 12) was investigated by measuring the amount of adsorbed SDS and PVP, ? potential, and dispersion stability. The conformation of PVP adsorbed was also estimated using a spin-labeled polymer.

Kunio Esumi; Kenichi Sakai; Kanjiro Torigoe; Tsuneo Suhara; Hiroshi Fukui

1999-01-01

487

Preparation and characterization of electrospun core sheath nanofibers from multi-walled carbon nanotubes and poly(vinyl pyrrolidone).  

PubMed

Electrospinning is a versatile technique to prepare polymer fibers in nano to micrometer size ranges using very high electrostatic fields. Electrospun nanofibers with tunable porosity and high specific surface area have various applications, including chromatographic supports for protein separation, biomedical devices, tissue engineering and drug delivery matrices, and as key components in solar cells and supercapacitors. Unspinnable materials such as nanoparticles, nanorods, nanotubes or rigid conducting polymers can also be electrospun into fibers through co-axial electrospinning. In this study, we have prepared core-sheath nanofibers utilizing co-axial electrospinning. The core portion of these electrospun fibers consists of multi-walled carbon nanotubes and the sheath portion is poly(vinyl pyrrolidone) (PVP). Various morphologies were obtained by changing both core and sheath solution concentrations. The core-sheath nanofibers were characterized by scanning electron microscopy and transmission electron microscopy, to confirm core-sheath morphology, thermogravimetric analysis, and mechanical strength testing. The electrical conductivity of the surfaces of poly(vinyl pyrrolidone) fibers and poly(vinyl pyrrolidone)-multi-walled nanotube fibers were both 10(-15) S/m. The highest bulk conductivity observed for the poly(vinyl pyrrolidone)-multi-walled nanotube fibers was 1.2 x 10(-3) S/m. PMID:22755063

Miao, Jianjun; Miyauchi, Minoru; Dordick, Jonathan S; Linhardt, Robert J

2012-03-01

488

Preparation of Delaminated Clay Having a Narrow Micropore Distribution in the Presence of Hydroxyaluminum Cations and Polyvinyl Alcohol  

Microsoft Academic Search

The pillaring of Na-montmorillonite with cationic oligomers of hydroxyaluminum (COHA) in the presence of an aqueous solution of polyvinyl alcohol resulted in the formation of a clay having a large surface area and pore volume. The pore-size distribution determined from a N2 adsorptiordde- sorption hysteresis was narrow and centered at about 25 ~. The peak width at half height in

Kenzi Suzuki; KAORU KAWASE; HIROSHI SAKAMI; SHOZO IIDA

1988-01-01

489

Reanalysis of updated mortality among vinyl and polyvinyl chloride workers: Confirmation of historical evidence and new findings  

Microsoft Academic Search

BACKGROUND: The production of vinyl chloride (VC) and polyvinyl chloride (PVC) involves the use of various chemicals, some known to be toxic and potentially or definitely carcinogenic. The related potential risk often has not been properly investigated. Updated cancer mortality among different subgroups of workers employed in a VC-PVC production plant located in Porto Marghera (Italy) was re-analyzed using an

Valerio Gennaro; Marcello Ceppi; Paolo Crosignani; Fabio Montanaro

2008-01-01

490

Cost Estimation of Butadiene-Grafted Polyvinyl Chloride Produced by Gas Phase Radiation-Induced Graft Polymerization.  

National Technical Information Service (NTIS)

Butadiene gas in contact with polyvinyl chloride (PVC) powder is easily graft-polymerized onto PVC by Co-60 gamma irradiation. The product polymer has a high impact strength comparable with that of blended PVC and a modifier (ABS, MBS, chlorinated polyeth...

K. Yoshida K. Araki

1976-01-01

491

A study of the thermodynamics of chitosan interaction with polyvinyl alcohol and polyethylene oxide by differential scanning calorimetry  

Microsoft Academic Search

Chitosan\\/polyvinyl alcohol and chitosan\\/polyethylene oxide blend films were prepared by coagulation from solutions. The interaction\\u000a energy density B and interaction parameter x\\u000a 12 of the components were estimated from the change in the melting point of the synthetic component in the blends.

E. S. Sashina; A. V. Vnuchkin; N. P. Novoselov

2006-01-01

492

Structural and magnetic properties of nanoscale iron oxide particles synthesized in the presence of dextran or polyvinyl alcohol  

Microsoft Academic Search

Magnetite\\/maghemite nanoparticles were synthesized in the presence of either dextran or polyvinyl alcohol, yielding cluster- and necklace-like aggregates, respectively. Magnetization, Mössbauer spectroscopy, and microscopy measurements indicate that the arrangement of the particles within the aggregates affects the magnetic properties of the particles resulting in smaller particles in the clusters having higher superparamagnetic blocking temperatures than larger particles in the necklaces.

Heath Pardoe; Wanida Chua-anusorn; Timothy G. St. Pierre; Jon Dobson

2001-01-01

493

Fabrication and operation of a system for the PVA (polyvinyl alcohol) coating of polymer microshells with trace gas fill  

SciTech Connect

Polymer microshells with a PVA (polyvinyl alcohol) coating are produced for the ICF Program by the Fusion Target Fabrication (FTF) Group at Lawrence Livermore National Laboratories. A PVA coating greatly reduces the permeation of gas through a polymer microshell. The equipment and procedures used in the production of PVA coated microshells are discussed. 6 figs.

King, K.J.

1988-03-31

494

Photocrosslinkable polyvinyl alcohol hydrogels that can be modified with cell adhesion peptides for use in tissue engineering  

Microsoft Academic Search

Photoactive polyvinyl alcohol hydrogels (PVA) have been investigated for use as tissue engineering scaffolds. These materials allow in situ polymerization for minimally invasive implantation methods. The mechanical properties of these materials can be tailored for a variety of soft tissue applications. The Young's modulus and ultimate tensile strength of PVA hydrogels are increased with increasing polymer concentration, and highly elastic

Rachael H. Schmedlen; Kristyn S. Masters; Jennifer L. West

2002-01-01

495

The histochemical localization of lactic dehydrogenase isoenzymes in the rat nephron by means of an improved polyvinyl alcohol method  

Microsoft Academic Search

The histochemical localization of lactic dehydrogenase (LDH) activity and the prevailing type of isoenzyme in different segments of the nephron in male and female rats are described. Polyvinyl alcohol was added to the incubation medium in order to reduce enzyme diffusion. Localization of the reaction product was further improved by the use of a high concentration of Nitro BT (and

N. O. Jacobsen

1969-01-01

496

Fungal colonization of soil-buried plasticized polyvinyl chloride (pPVC) and the impact of incorporated biocides  

Microsoft Academic Search

Plasticized polyvinyl chloride (pPVC) with or without incorporated biocides was buried in grassland and forest soil for up to 10 months. The change with time in viable counts of fungi on the plastic surface was followed, together with the percentage capable of clearing the two plasticizers dioctyl adipate (DOA) and dioctyl phthalate (DOP). With time fungal total viable counts (TVC)

H. A. Sabev; P. S. Handley; G. D. Robson

2006-01-01

497

Supercritical extraction of binder containing poly(vinyl butyral) and dioctyl phthalate from barium titanate–platinum multilayer ceramic capacitors  

Microsoft Academic Search

Supercritical extraction using carbon dioxide was examined for the removal of binder from multilayer ceramic capacitors. The binder contained poly(vinyl butyral) (PVB) and dioctyl phthalate (DOP), and the dielectric and metal electrode materials were barium titanate and platinum, respectively. At 40 MPa of carbon dioxide at 95 °C, approximately 55 wt % of the binder could be removed, and this

Rajesh V. Shende; Daniel S. Krueger; Stephen J. Lombardo

2001-01-01

498

Coagulation size of freezable water in poly(vinyl alcohol) hydrogels formed by different freeze\\/thaw cycle periods  

Microsoft Academic Search

The coagulation size of freezable water in a poly(vinyl alcohol) (PVA) hydrogel was investigated as a function of the freeze\\/thaw cycle period using thermal analysis. The melting temperature of ice in the gel shifted to a lower temperature than that of normal ice. This temperature depression can be interpreted in terms of the coagulation size of freezable water in the

Tatsuro Nakano; Takahiko Nakaoki

2011-01-01

499

Mechanical evaluation of poly(vinyl alcohol)-based fibrous composites as biomaterials for meniscal tissue replacement  

Microsoft Academic Search

In this study, poly(vinyl alcohol) (PVA) hydrogels were reinforced with ultrahigh molecular weight polyethylene (UHMWPE) and PP fibers and evaluated as potential nondegradable meniscal replacements. An investigation of hydrogel and composite mechanical properties indicates that fiber-reinforced PVA hydrogels could replicate the unique anisotropic modulus distribution present in the native meniscus; the most commonly damaged orthopedic tissue. More specifically, fibrous reinforcement

Julianne L. Holloway; Anthony M. Lowman; Giuseppe R. Palmese

2010-01-01

500

Poly(vinyl alcohol) cryogels employed as matrices for cell immobilization. 3. Overview of recent research and developments  

Microsoft Academic Search

Poly(vinyl alcohol) cryogels, which are prepared by the freeze-thawing of concentrated aqueous solutions of the polymer, are promising gel carriers for cell immobilization. These carriers possess definite advantages when compared to other hydrogels commonly used for the same purposes. Similar benefits are as follows: (i) PVA cryogels have very high micro- and macroporosities which provide favored conditions for the nonhindered

V. I. Lozinsky; F. M. Plieva

1998-01-01