Showing papers on "Vinyl alcohol published in 1995"

Standard Pressure Volume Temperature Data for Polymers

Abstract: 1. INTRODUCTION Pressure-Volume-Temperature (PVT) Data: Equilibrium and Nonequilibrium States of Polymers Scope of This Data Collection Equipment for PVT Measurements: Piston-Die Technique Confining Fluid Technique Equipment Used for Data in This Book Experimental Procedures: Stan- dard PVT Runs Sample Preparation Determination of the Specific Volume at Ambient Conditions Data Interpretation: Tables and Graphs in This Collection Liquids Materials Undergoing a Glass Transition Materials Having a Melt Transition Filled Materials and Blends Application of PVT Data Empirical and Theoretical Fits to PVT Data References 2. HYDROCARBONS n-Undecane (C11H24) n-Tetradecane (C14H30) n-Hexadecane (C16H34) n-Tetracosane (C24H50) n-Hexatriacotane (C36H74) n-Tetratetracotane (C44H90) 3. HYDROCARBON POLYMERS Polyethylene (linear) Polyethylene (branched) Polyethylene wax (M ~2100) Polyethylene wax (M ~1000) Poly(propylene) (atactic) Polypropylene (atactic) Polypropylene (isotactic) Poly(1-butene) (atactic) Poly(1-butene) (isotactic) Poly(1-octene) Polyisobutylene (M ~ 4.2 x 105) Polyisobutylene (M ~ 300) Polyisoprene (hydrogenated) Poly(4-methyl pentene-1) Polynorbornene Hydrocarbon resin Poly(ethylene-co-propylene) (23% polypropylene) Poly(ethylene-co-propylene) (57% propylene) Poly(ethylene-co-propylene) (76% propylene) Poly(ethylene-co-propylene) (84% propylene) Polybutadiene (M ~ 2.33 x 105) Polybutadiene (cis & trans) Polybutadiene (cis) Polybutadiene (M ~ 3000) Polybutadiene (M ~ 1000) Natural rubber 4. ETHYLENE POLYMERS crylic acid) Poly(ethylene-co-methacrylic acid) (9% methacrylic acid) Poly(ethylene-co-methacrylic acid) (11.5% methacrylic acid) Poly(ethylene-co-methacrylic acid) (12% methacrylic acid) Poly(ethylene-co-methacrylic acid) (15% methacrylic acid) Poly(ethylene-co-methacrylic acid) (20% methacrylic acid) Ionomer (~ 1.5% Na) Ionomer (~ 2.2% Na) Poly(ethylene-co-acrylic acid) (9% acrylic acid) Poly(ethylene-co-acrylic acid) (10% acrylic acid) Poly(ethylene-co-acrylic acid) (20% acrylic acid) Poly(ethylene-co-vinyl alcohol) (56% vinyl alcohol) Poly(ethylene-co-vinyl alcohol) (62% vinyl alcohol) Poly(ethylene-co-vinyl alcohol) (70% vinyl alcohol) 5. STYRENICS Polystyrene (M ~ 1.1 x 105) Polystyrene (M ~ 34500) Polystyrene (M ~ 9000) Polystyrene (M ~ 910) Poly(4-chloro styrene) Poly(styrene-block-hydrogenated butadiene) 6. ACRYLICS Poly(methyl methacrylate) (M ~ 1 x 105) Poly(methyl methacrylate) (M ~ 40000) Poly(methyl methacrylate) (M ~ 25000) Poly(methyl methacrylate) (M ~ 10000) Poly(ethyl methacrylate) Poly(propyl methacrylate) Poly(n-propyl methacrylate) Poly(n-butyl methacrylate) Poly(n-hexyl methacrylate) Poly(lauryl methacrylate) Poly(isobutyl methacrylate) Poly(methyl acrylate) Poly(ethyl acrylate) Poly(n-propyl acrylate) Poly(n-butyl acrylate) Poly(acrylic acid) Poly(methacrylic acid) 7. POLYACRYLONITRILE AND COPOLYMERS Polyacrylonitrile Poly(styrene-co-acrylonitrile) (25% acrylonitrile) Poly(acrylonitrile-co-butadiene) (67% butadiene) Nitrile rubber compound 8. OTHER C-C MAIN CHAIN POLYMERS Poly(vinyl acetate) Poly(vinyl alcohol) Poly(vinyl butyral) Poly(vinyl carbazole) Poly(vinyl chloride) Poly(vinyl fluoride) Poly(vinyl formal) Poly(vinylidene fluoride) Poly(tetrafluoro ethylene) Fluoropolymer glass Fluoroelastomer compound Perfluoroelastomer compound 9. POLYETHERS Poly(methylene oxide) (homopolymer) Poly(methylene oxide) (copolymer) Poly(ethylene oxide) (M x105) Poly(ethylene oxide) (M ~ 18500) Poly(ethylene oxide) (M ~ 1540) Poly(ethylene oxide) (M ~ 600) Poly(ethylene oxide) (M ~ 300) Poly(ethylene oxide) mono methyl ether (M ~ 750) Poly(ethylene oxide) mono methyl ether (M ~ 350) Poly(ethylene oxide) dimethyl ether (M ~ 1000) Poly(ethylene oxide) dimethyl ether (M ~ 600) Poly(propylene oxide) (M ~ 4000) Poly(propylene oxide) (M ~ 2000) Poly(propylene oxide) (M ~ 1025) Poly(propylene oxide) (M ~ 400) Poly(propylene oxide) dimethyl ether (M ~ 2000) Poly(propylene oxide) dimethyl ether (M ~ 1025) Poly(propylene oxide) dimethyl ether (M ~ 400) Poly(hexafluoropropylene oxide) (M ~ 7000) Poly(hexafluoropropylene oxide) (M ~ 2000) Silicone fluid (commercial) Poly(dimethyl siloxane) (M ~ 1.5 x 106) Poly(dimethyl siloxane) (M ~ 2.24 x 105) Poly(dimethyl siloxane) (M ~ 17200) Poly(dimethyl siloxane) (M ~ 9670) Poly(dimethyl siloxane) (M ~ 3900) Poly(dimethyl siloxane) (M ~ 870) Poly(dimethyl siloxane) (M ~ 340) 10. POLYAMIDES Nylon 6 Nylon 7 Nylon 9 Nylon 11 Nylon 12 Nylon 4/6 Nylon 6/6 Nylon 6/6 (rubber toughened) Nylon 6/7 Nylon 6/8 Nylon 6/9 Nylon 6/10 Nylon 6/10 (pure) Nylon 6/12 Nylon 13/13 Nylon 6I/6T Aramid fiber 11. POLYESTERS Poly(ethylene adipate) Poly(ethylene succinate) Polycaprolactone Poly-L-lactide Poly(ethylene isophthalate) Poly(ethylene terephthalate) Poly(ethylene naphthenoate) Poly(butylene terephthalate) Bisphenol A isophthalate Polyarylate 12. VARIOUS MAIN CHAIN AROMATICS Polycarbonate Chloral polycarbonate Poly(2-6-dimethyl phenylene oxide) Phenoxy resin Polyetherimide Polyimide (film) Poly(ether ether ketone) Poly(ether sulphone) Polysulfone Poly(azomethine ether) (n = 4) Poly(azomethine ether) (n= 7) Poly(azomethine ether) (n= 8) Poly(azomethine ether) (n= 9) Poly(azomethine ether) (n= 10)Poly(azomethine ether) (n= 11) 13. BLENDS Polystyrenepoly(vinyl methyl ether) blend (90/10) Polystyrenepoly(vinyl methyl ether) blend (80/20) Polystyrenepoly(vinyl methyl ether) blend (70/30) Polystyrenepoly(vinyl methyl ether) blend (60/40) Poly- styrenepoly(vinyl methyl ether) blend (50/50) Polystyrenepoly(vinyl methyl ether) blend (40/60) Polystyrenepoly(vinyl methyl ether) blend (30/70) Polystyrenepoly(vinyl methyl ether) blend (20/80) Poly- styrenepoly(vinyl methyl ether) blend (10/90) Poly(2,6-dimethyl phenylene oxide)polystyrene blend (90/10) Poly(2,6-dimethyl phenylene oxide)polystyrene blend (80/20) Poly(2,6-dimethyl phenylene oxide)poly- styrene blend (70/30) Poly(2,6-dimethyl phenylene oxide)polystyrene blend (60/40) Poly(2,6-dimethyl phenylene oxide)polystyrene blend (50/50) Poly(2,6-dimethyl phenylene oxide)polystyrene blend (40/60) Poly(2,6-dimethyl phenylene oxide)polystyrene blend (30/70) Poly(2,6-dimethyl phenylene oxide)polystyrene blend (20/80) Poly(2,6-dimethyl phenylene oxide)polystyrene blend (10/90) Polyethersulphonepoly- (ethylene oxide) blend (40/60) Polyethersulphonepoly(ethylene oxide) blend (20/80) 14. MISCELLANEOUS Starch triacetate >Poly(ethylene-co-vinyl acetate) (14% vinyl acetate) Poly(ethylene-co-vinyl acetate) (18% vinyl acetate) Poly(ethylene-co-vinyl acetate) (25% vinyl acetate) Poly(ethylene-co-vinyl acetate) (28% vinyl acetate) Poly(ethylene-co-vinyl acetate) (33% vinyl acetate) Poly(ethylene-co-vinyl acetate) (40% vinyl acetate) Poly(ethylene-co-vinyl acetate) (65% vinyl acetate) Poly(ethylene-co-methacrylic acid) (4% metha

Preparation and characterization of pH-sensitive, interpenetrating networks of poly(vinyl alcohol) and poly(acrylic acid)

Abstract: Hydrogels with varying cross-linking ratio and ionic content were prepared from interpenetrating networks of poly(vinyl alcohol) and poly(acrylic acid). Equilibrium swelling studies were conducted and the average molecular weight between cross-links, Mc, and mesh size were determined. Hydrogels with large Mc, values were found to swell to a greater extent than those with small Mc values. It was also observed that an increase in Mc yielded faster swelling and deswelling rates, as the rates for membranes with Mc = 18,000 were about twice as fast as were the rates for membranes with Mc = 34,000. Oscillatory swelling behavior was investigated in response to changes in the pH and ionic strength of the swelling medium. A change in pH from 3 to 6 caused an ionization of the hydrogels and an increase in the weight swelling ratio, with a greater increase exhibited by IPNs with a higher ionic content. Increase in pH also caused an increase in the average mesh size. © 1995 John Wiley & Sons, Inc.

Conducting Polyaniline Nanoparticle Blends with Extremely Low Percolation Thresholds

Abstract: Blends of HCl-doped polyaniline (PANI.HCl) nanoparticles with the following conventional polymers, poly(vinyl chloride), polystyrene, poly(methyl methacrylate), poly(vinyl acetate), and poly(vinyl alcohol) (PVA), were prepared by suspending preformed submicronic PANI-HCl particles in the solutions of the matrix polymers and sonicating the suspension for 1.5 h. The submicronic PANI-HCl particles were prepared by oxidative dispersion polymerization using poly(vinyl methyl ether) (PVME) stabilizer. The particles contained 4.4 wt % PVME and had a conductivity of 4.96 S/cm. They had an oblong shape (250 nm×190 nm). Sonication breaks the particles to sizes less than 20 nm. The blend films exhibit an extremly low percolation threshold (f p ) in every case. The volume fraction of PANI-HCl at the percolation threshold for the above mentioned matrices lies in the range 2.5×10 -4 to 4×10 -4 . Transmission electron microscoopy of PANI-HCl-PVA blend films directly cast on carbon-coated TEM grids reveals connectivity at compositions close to f p . Self-assembly of the nanoparticles is evident from the TEM pictures

Studies on the preparation and properties of conductive polymers. VIII. Use of heat treatment to prepare metallized films from silver chelate of PVA and PAN

Abstract: Metallized polymer films were prepared from polyacrylonitrile or poly(vinyl alcohol) silver chelate solution by heat treatment. These metallized film exhibited low surface resistivity around 100Ω/cm2. The surface of these conductive films was proved to be metallized using X-ray analysis. The metal adhered on the film was believed to be responsible for the improvement of electrical conductivity. The effects of types and concentrations of silver salt, types and volume of solvent, and drying time on the conductivity of metallized films were investigated. © 1995 John Wiley & Sons, Inc.

Crystallization and compatibility of poly(vinyl alcohol)/poly(3‐hydroxybutyrate) blends: Influence of blend composition and tacticity of poly(vinyl alcohol)

Abstract: Compatibility of a crystalline/crystalline polymer blend, poly(vinyl alcohol) (PVA)/poly(3-hydroxybutyrate) (PHB), was studied by high-resolution solid-state 13C-NMR spectroscopy. The 1H T1 measurement demonstrated that both the compatibility and the domain size depend on the composition of the blend. The PVA/PHB blend is compatible only when the blend contains a large amount of PVA. The domain sizes of the compatible blend are less than 200 A. In the pulse saturation transfer (PST) MAS NMR spectra, the carbonyl carbon resonance from PHB showed a downfield shift, which indicates that the compatibility of the PVA/PHB blends is due to the hydrogen-bonding interaction in the amorphous phase. The DSC measurement showed that the compatible blends adopt low crystallinity for both PHB and PVA. The crystallization in these blends is likely to be distributed by the hydrogen-bonding interaction in the amorphous phase. The compatibility of PVA/PHB is also affected by the tacticity of PVA. The compatible composition range of the syndiotacticrich PVA/PHB blend is wider than that of the atactic-PVA/PHB blend. It is likely that the capacity to form the hydrogen bond depends on the tacticity of PVA. © 1995 John Wiley & Sons, Inc.

Polymeric networks from water-soluble prepolymers

Abstract: The present invention describes a water-soluble crosslinkable prepolymer that comprises, in the copolymer chain, units derived from the following monomeric structural units: a vinyl lactam (a), vinyl alcohol (b), optionally a lower alkanecarboxylic acid vinyl ester (c), a vinylic crosslinking agent (d) and optionally a vinylic photoinitiator (e); a process for the preparation of the novel prepolymers; crosslinked water-insoluble polymeric networks therefrom; hydrogels and moulded articles made from the crosslinked water-insoluble polymeric networks, especially contact lenses; and a process for the manufacture of hydrogels and finished contact lenses using the mentioned crosslinkable water-soluble prepolymers.

Study of cryostructuration of polymer systems. XI. The formation of PVA cryogels by freezing–thawing the polymer aqueous solutions containing additives of some polyols

Abstract: The influence of the presence of some polyols in initial poly(vinyl alcohol) aqueous solutions on rheological and thermal properties of the cryogels, which were produced by the freezing–thawing method, was investigated. The polyol additives (cosolvents) were as follows: glycerol, propylene glycol, mono-, di-, and triethylene glycols, and oligoethylene glycols (PEG-400 and PEG-1000). It was shown that the introduction of glycerol, propylene, or ethylene glycols into the polymer solution resulted in a decrease of cryogel's shear modulus and fusion temperature, whereas the use of triethylene and higher ethylene glycol oligomers as cosolvents gave rise to an increase in the gel's strength and thermostability, and diethylene glycol exhibited a transitional influence. The possible mechanism of the action of reinforcing cosolvents is discussed. © 1995 John Wiley & Sons, Inc.

Competitive Adsorption of Citric Acid and Poly(vinyl alcohol) onto Alumina and Its Influence on the Binder Migration during Drying

Abstract: Poly(viny1 alcohol) (PVA) and citric acid (CA) are a commonly used binder and dispersant, respectively, for aqueous Al2O3 slurries. The competitive adsorption of these additives on A12O3 from aqueous solution was studied, as was the influence of this competition on the binder migration in centrifugally cast compacts during the drying process. PVA did not influence the adsorption behavior of CA. However, the adsorption of PVA on α-Al2O3 was strongly reduced by the presence of CA. This displacement of PVA by CA led to a drastically increased segregation of PVA during the drying process.

Dynamic Light Scattering and Dynamic Viscoelasticity of Poly(vinyl alcohol) in Aqueous Borax Solutions. 5. Temperature Effects

Abstract: Steady viscosity, dynamic viscoelasticity (DVE), and dynamic light scattering (DLS) measurements were made to study the effects of temperature, T, on association behaviors of poly(vinyl alcohol) (PVA) with weight-average degree of polymerization DPw = 350 in aqueous Borax solution. Intrinsic viscosity, [η], monotonically decreased by 23% with a rise in T from 10 to 65 °C. At low T, enhancement in viscosity was observed with increasing polymer concentration, C, due to formation of viscoelastic network with the didiol complex as temporal cross-links, and the time−temperature superposition principle was found to be applicable for construction of a composite curve at each C. Those composite curves were further reduced so as to give one master curve. The system tended to lose its viscoelastic nature, when raising the temperature, toward a viscous solution owing to a decrease in the number of the didiol complexes as well as the shrinkage of the PVA chains. We found from analysis of DVE and DLS data that a clear...

Separation of MTBE-Methanol Mixtures by Pervaporation

Abstract: Membranes made of a polymer blend of poly(acrylic acid) and poly(vinyl alcohol) were evaluated for the separation of methanol from methyl tert-butyl ether (MTBE) by pervaporation. The influence of the blend composition and the feed composition on the pervaporation performance were investigated. Methanol permeates preferentially through all tested blend membranes, and the selectivity increases with increasing poly(vinyl alcohol) content in the blends. However, a flux decrease is observed with increasing poly(vinyl alcohol) content. With increasing feed temperature the flux increases, and the selectivity remains constant. In addition, the influence of crosslinking on the permselectivity was investigated. The pervaporation flux decreases with increasing crosslinking density, but the selectivity is enhanced. This is due to a more rapid decrease in the component flux of MTBE compared to that of methanol.

Morphology and barrier properties of oriented blends of poly(ethylene terephthalate) and poly(ethylene 2,6-naphthalate) with poly(ethylene-co-vinyl alcohol)

Abstract: Morphology and oxygen permeability studies were carried out for blends of poly(ethylene terephthalate), PET, and poly(ethylene 2,6-naphthalate), PEN, with poly(ethylene-co-vinyl alcohol), EVOH. PET/EVOH blends are seen as a possible substitute for poly(vinylidene chloride)-coated PET packaging films. The effects of several processing parameters such as draw temperature and draw ratio on blend morphology and barrier properties suggest that the morphology of the EVOH phase dictates to a large extent the oxygen permeabilities of these blends. The relationships between morphology and oxygen permeability and explained are explained by consideration of two-phase conduction models. The model of Fricke is found to be a good predictor of the barrier properties of the PET/EVOH system. The oxygen permeability of PET was reduced by a factor of 4.2 with the addition of 20 wt% EVOH and that of PEN by a factor of 2.7 with the addition of 15 wt% EVOH. Water vapor permeabilities and mechanical properties of PET and PEN were only slightly affected by the addition of 15 wt% EVOH.

Thermal Decomposition Chemistry of Poly(vinyl alcohol) Char Characterization and Reactions with Bismaleimides

Abstract: The fundamental condensed phase processes which lead to char formation during the fue-like pyrolysis of polyvinyl alcohol), PVA, and PVA-cent.aining maleimides were characterized using CPIMAS 13C NMR. In addition to evidence of the well known chain-stripping elimination of ElzO and the chain-scission reactions, which occur during the pyrolysis of pure PVA, evidence is presented in support of cyclization and radical reaction pathways responsible for the conversion ( of unsa ated carbons into aliphatic carbons. Two general mechanisms; on escribed as a physical encapsulation, and the other a lowering of e average volatility of certain degradation products, are proposed for the primary modes of action of maleimides on the pyrolysis of PVA. j

PVOH-based coating solutions

Abstract: An improved PVOH-based coating solution for application to a polymeric substrate. The coating solution includes poly(vinyl alcohol), a formaldehyde-containing crosslinking agent and a crosslinking-promoting acid catalyst which lowers the pH of the solution to about 3.5 or less and, preferably, to about 3 or less. The coating solution exhibits improved viscosity stability, particularly with the addition of a second acid catalyst. The coating solution also provides improved crosslinking and oxygen barrier characteristics upon drying.

Hydrophilic polymer alloy, fiber and porous membrane comprising this polymer alloy, and methods for preparing them

Abstract: A hydrophilic polymer alloy which has a permanent hydrophilic nature, a sufficient mechanical strength and a high safety and which is suitable for the formation of hydrophilic porous membranes manufacturable by an industrially advantageous process can be prepared by blending an amorphous hydrophilic copolymer (X) containing 10 mole % or more of an ethylene unit, 10 to 60 mole % of a vinyl alcohol unit and 1 mole % or more of a vinyl acetate unit with a polyolefin (Y). Furthermore, this polymer alloy is also suitable for the formation of hydrophilic (porous) fibers having a sufficient mechanical strength and antistatic function.

Effect of solution concentration on the gelation of aqueous polyvinyl alcohol solution

Abstract: The concentration dependence of cryogenic gelation for aqueous solution of poly(vinyl alcohol) was studied by measuring the apparent gel fraction G and the swelling ratio Q of the gel formed by freezing and thawing. It was found that for the gelation process there were three distinct regions of solution concentration bounded by two concentrations C gel and C * gel . The gel started to form at C = C gel , while no visible gel could be detected even upon repeated freezing and thawing of the extremely dilute solutions of C C * gel . In the intermediate concentration region, C gel < C < C * gel , which covers three orders of magnitude in concentration, gel and sol phases coexist. Both concentration dependencies of G and Q show two branches jointed at a concentration very close to the overlap concentration C * . The curve of G.Q versus C shows a sharp cusp. In case the sharp cusp concentration is really the value of C * , gelation offers a precise method to determine the overlap concentration.