VINYLACETATE COPOLYMER

Unexpectedly, PVC/rubber blends show under certain circumstances quite a different morphology. This was shown experimentally for chlorinated polyethylene and ethylene-vinylacetate copolymers as rubber phase. 

Figure 4.24. Vinyl acetate, ethylene and ethylene-vinylacetate copolymer formulae...

Terpolymer ethylene, propylene, diene Expandable (or Expanded) Polystyrene Environmental Stress Cracking Electrostatic Discharge Ethylene-TetraEluoroEthylene Ethylene-VinylAcetate copolymers... 

Zingone G, Rubessa D. Release of carbamazepine from solid dispersions with polyvinyl-pyrrolidone/vinylacetate copolymer (PVP/VA). STP Pharm Sci 1994 4 122-127. 

Membrane-reservoir systems based on solution-diffusion mechanism have been utilized in different forms for the controlled delivery of therapeutic agents. These systems including membrane devices, microcapsules, liposomes, and hollow fibres have been applied to a number of areas ranging from birth control, transdermal delivery, to cancer therapy. Various polymeric materials including silicone rubber, ethylene vinylacetate copolymers, polyurethanes, and hydrogels have been employed in the fabrication of such membrane-reservoir systems (13). 

The pronounced amplitude dependence of the complex modulus, referred to as the Payne effect, has also been observed in low viscosity media, e.g., composites of carbon black with decane and liquid paraffin [50], carbon black suspensions in ethylene vinylacetate copolymers [51], and clay/water suspensions [52, 53]. It was found that the storage modulus decreases with... 

Even dynamic measurements have been made on mixtures of carbon black with decane and liquid paraffin [22], carbon black suspensions in ethylene vinylacetate copolymers [23], or on clay/water systems [24,25]. The corresponding results show that the storage modulus decreases with dynamic amplitude in a manner similar to that of conventional rubber (e.g., NR/carbon blacks). This demonstrates the existence and properties of physical carbon black structures in the absence of rubber. Further, these results indicate that structure effects of the filler determine the Payne-effect primarily. The elastomer seems to act merely as a dispersing medium that influences the magnitude of agglomeration and distribution of filler, but does not have visible influence on the overall characteristics of three-dimensional filler networks or filler clusters, respectively. The elastomer matrix allows the filler structure to reform after breakdown with increasing strain amplitude. 

Vojnovic D, Rubessa F, Bogataj M, Mrhar A. Formulation and evaluation of vinylpyrrolidone/vinylacetate copolymer microspheres with griseofulvin. / Microencapsul 1993 10(1) 89-99. 

Homopolymers and both ethylacrylate and vinylacetate copolymers of 8-hydroxyqulnolyl acrylate, (5), gave large zones of inhibition in agar dish tests due to rapid self-hydrolysis from the polymers. Thus, the polymer systems are not suitable for slow release. Tests are underway on polymers of the extended chain analog, (6). 

V,V dimethyl acetamide Ethylene-vinylacetate copolymer Hour... 

Ethylene and vinylacetate copolymer was irradiated at -196° C (137). Methyl radicate, however, were not observed but there was an apparent singlet spectrum with some shoulders. 

Films. Three films were included in this study. Low density polyethylene (LDPE) was included as a representative polyolefin. It is not considered to be a barrier polymer. It has permeabilities to selected aroma compounds slightly higher than the permeabilities of polypropylene and high density polyethylene (1). A vinylidene chloride copolymer (co-VDC) film was included as an example of a barrier that is useful in both dry and humid conditions. The film was made from a Dow resin which has been designed for rigid packaging applications. A hydrolyzed ethylene-vinylacetate copolymer (EVOH) film was included as an example of a barrier film that is humidity sensitive. The polymer was a blend of resins with total composition of 38 mole% ethylene. 

The theory was found to predict complex behavior near the phase separation conditions. As the rate of shear increases, first, the system undergoes homogenization, then demixing, followed by another homogenization and demixing. At high rates of shear, the system should behave similarly as in a quiescent state. These predictions were found to be in qualitative agreement with experimental data, e.g., for blends of ethylene-vinylacetate copolymer with chlorinated polyethylene, EVAc/CPE, or polystyrene with poly(vinyl methyl ether), PS/PVME [Hindawi et al., 1992 Eernandez ef fl/., 1993, 1995]. 

Ethylene-vinylacetate blends with PVC have been widely used in Europe as permanent polymeric plasticizers for PVC. Low cost and good weatherability of these blends permitted their use in window profiles, cable jacketing and other outdoor applications. Ethylene vinylacetate copolymer with 65-75% vinyl acetate content is quite miscible with PVC exhibiting a single T for the blend [Hammer, 1971 Ranby, 1975 Rellick and Runt, 1985]. Two phases are apparent when the vinylacetate is < 45%. Vinylchloride grafted ethylene-vinyl acetate copolymers have also been used for blending with PVC. 

Trimethylcyclohe.xanone [873-94-9] (TMC-one, 3,3,5-trimethylcyclohexanone) is a saturated cyclic ketone. It is a colorless high boiler with an aromatic odor reminiscent of menthol. Trimethylcyclohexanone is only moderately miscible with water, but is miscible in all proportions with all organic solvents. It is chemically closely related to isophorone. Trimethylcyclohexanone dissolves cellulose nitrate, low molecular mass PVC grades, poly(vinyl acetate), vinyl chloride-vinylacetate copolymers, chlorinated rubber, alkyd resins, unsaturated polyester resins, epoxy resins, acrylic resins, etc. 

Classification Polyvinylpyrrolidone-vinylacetate copolymer Definition Copolymer obtained by free-radical polymerization of 6 parts of vinylpyrrolidone and 4 parts vinyl acetate in I PA Formula (C6H,N0) (C,H602) ... 

Chattopadhyay, S., Chaki, T. K., Bhowmick, A. K., Heat shrinkability of electron-beam-modified thermoplastic elastomeric films from blends of ethylene-vinylacetate copolymer and polyethylene. Radiation Physics and Chemistry 2000, 59(5-6), 501-510. 

Alkane sulfonates are applied in a widespread manner in emulsion polymerization. They are used as processing aids, in particular in the emulsion polymerization of vinyl chloride, vinyl acetate, styrene and acrylonitrile. Because they possess no double bonds, alkane sulfonates do not act as radical chain stoppers. Well-known lattices derived from emulsion polymerization are poly(vinyl chloride), ethylene-vinylacetate copolymers, polyacrylates, and butadiene and chloroprene rubbers. Alkane sulfonates also offer good stabilizing effects in lattices against coagulation by fillers. 

IN-LINE FIBRE-OPTIC NEAR-INFRARED SPECTROSCOPY FEASIBILITY STUDIES FOR THE SIMULTANEOUS MONITORING OF VINYL ACETATE AND ERUCAMIDE ADDITIVE CONCENTRATIONS IN POLYETHYLENE-VINYLACETATE COPOLYMERS Vedula S Hansen M G Deshpande B J Tennessee,University (SPE)... 

The major polymers with whieh PVC ean be alloyed are aerylonitrile-butadiene eopolymers, aerylonitrile-butadiene-styrene terpolymer, ethylene-vinylacetate copolymers, chlorinated polyethylene, chlorosulfonated polyethylene, thermoplastic polyurethanes, acrylics and methacrylics, and polycaprolactone. Table 18 lists the property enhancements achieved by blending these polymers with PVC. 

EVM ethylene-vinylacetate copolymer (previous code EVA or EVAC)... 

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