Ethylene with Vinyl Acetate

Various copolymers of ethylene with vinyl acetate are prepared by a free-radical mechanism in emulsion polymerizations. Both reactivity ratios are close to The degree of branching in these 

Vinyl acetate residues in ethylene-vinyl acetate copolymers reduce the regularity of polyethylene. This reduces crystallinity in the polymer. Materials containing 45% vinyl acetate are elastomers and can be crosslinked with peroxide. 

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The copolymerisation of ethylene with vinyl acetate (VA) is another method by which the crystallinity of polyethylene can be reduced and a rubbery polymer obtained. The final properties of the copolymer depend on the VA content at a VA level of 50% the copolymer is entirely amorphous, and elastomeric grades generally contain 40-60% VA by weight. The oil resistance of the copolymer is also dependent on the VA content in general, however, this lies between that of SBR and polychloroprene. It is swollen by most organic solvents and not resistant to animal and vegetable oils, but has some resistance to weak acids and alkalis at ambient temperature. 

Newman, R. D. Prausnitz, J. M., "Thermodynamics of Concentrated Polymer Solutions Containing Polyethylene, Polyisobutylene, and Copolymers of Ethylene with Vinyl Acetate and Propylene," AlChE J., 19, 704 (1973a). 

Braun and Guillet 84) investigated copolymers of ethylene with vinyl acetate and carbon monoxide as well as modified polyethylene waxes. While the crystallinity of such polymers can no longer be derived from their density, it was found that the GC method was equally successful with copolymers or modified K)fymers. Figure 9... 

Vinyl acetate homopolymers are simply-made adhesive bases manufactured by addition polymerization in the presence of water and stabilizers. They are made commercially by the batch reactor process or by the Loop reactor continuous process. External plasticizers such as dibutyl phthalate are often added to confer flexibility and to lower the temperature at which they form a film on drying. Higher-quality products may be made by the copolymerization of ethylene with vinyl acetate to form an EVA. This involves the safe handling of ethylene gas under high pressure, and the plant required is more complex and considerably more costly. The Loop process has considerable attraction in the field of pressure polymerization. 

General Description Polyethylenes consist of a family of thermoplastic resins obtained by polymerizing the gas ethylene [C2H4]. High molecular weight polymers (i.e., over 6,000) are the materials used in the plastics industry. Copolymers of ethylene with vinyl acetate, ethyl acrylate, and acrylic acid are commercially important,... 

Discuss the copolymers of ethylene with vinyl acetate. How are they prepared and used ... 

It is possible to raise affinity of a surface to other materials by introduction of polar units to a macromolecules by copolymerisation of ethylene with vinyl acetate [73,74], aciylonitrile [75], or methyl methacrylate [76],... 

A comparison of the emulsion and miniemulsion processes used to copolymerize ethylene with vinyl acetate [78] showed that, for batch processes, the extent of ethylene incorporation into the copolymer was greater for miniemulsions... 

Various copolymers of ethylene with vinyl acetate are prepared by free-radical mechanism in emulsion polymerizations. Both reactivity ratios are close to 1.0 [106]. The degree of branching in these copolymers is strongly temperature-dependent [107]. These materials find wide use in such areas as paper coatings and adhesives. In addition, some are hydrolyzed to form copolymers of ethylene with vinyl alcohol. Such resins are available commercially in various ratios of polyethylene to poly(vinyl alcohol), can range from 30% poly(vinyl alcohol) to as high as 70%. 

EVA derived from the copolymerization of ethylene with vinyl acetate. 

Modification of ethylene with vinyl acetate copolymers by glycidoxy-alkoxysilane has no effect on the strength of the adhesive contact ethylene copolymer - PET. However, the introduction of 1.5 wt% of this additive in SEVAMA leads to a significant (in 3.4 times) increase in adhesion strength of the system, and the destruction of the substrate is observed (Fig. 3). 

Generally, low-density polyethylenes, poly(vinyl chloride), potybutylene, or copol3miers of ethylene with vinyl acetate are used for plastic mulches, and their ratio is adjusted to provide protection for specific growing periods. The photodegradation of... 

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