Ethylene-vinylacetate polymers

Polyacetal resin compositions having excellent wear resistance were prepared by Kim [4], These resins consisted of polyoxymethylene polymer, ethylene vinylacetate, melamine, triethyleneglycol-bis-3-(3-t-butyl-4-hydroxy-5-methylphenyl)-propionate, and hydroxyl pentaerythritol fatty acid ester. 

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 ESD behavior can be provided by blending in a flexible-chain polymer with an active -OH or -SH group, viz. polyvinyl alcohol (PVAl), ethylene-vinylacetate (EVAc), polyvinylphenol (PVPh), a copolymer of ethylene oxide and epi-chlorohydrin (EO-CHR), maleated copolymer, aliphatic polysulfides, etc. These low performance resins have been incorporated into a variety of alloys and blends (see Table 1.79). 

Hassanpour, S., BGroylou, R, Jabbarzadeh, E., Thermal degradation of electron beam crosslinked polyethylene and (ethylene-vinylacetate) blends in hot water. Journal of Applied Polymer Science 2003,89,2346-2352. 

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. 

Copolymers, as the name implies, are produced from the polymerization of two different materials. Probably one of the most widely used copolymer emulsion adhesives is that based on vinyl acetate ethylenes, commonly referred to as VAEs (see Ethylene vinylacetate copolymers). These are produced by the copolymerization of vinyl acetate and 10-20% ethylene, the resulting polymer base possessing some superior properties over the PVA-based emulsions referred to above. These superior properties relate principally to the increased inherent flexibility of the dry VAE film due to the internal plasticization effect of the ethylene component in the polymer, which enhances adhesion to many difficult surfaces. There are, however, a number of other polymers and copolymers that are used as the formulating basis for alternative specialized emulsion adhesive systems. 

In addition to vinylsilanes, ATH- and MDH-filled ethylene vinylacetate copolymers can be effectively coupled to aminosilanes [37]. Fine and uniform ATH dispersion in the polymer leads to low H FFR compound viscosities (M FI) and high tear strength. The use of 3-aminopropyltriethoxysilane became an industrial standard for the production of reliable thermoplastic HFFR compounds. New primary/secondary aminosilane blends provide further improvements in the final HFFR compound [38]. Aminosilanes are also found in thermoplastic EVA, nonperoxide cross-linked. 

A polymer can be either natural or synthetic. Synthetic polymers are formed by addition or condensation polymerization reactions of monomer. If two or more different monomers are involved, a copolymer (such as ethylene vinylacetate) is obtained. 

The experimental protocol of our studies involved the exposure of fresh healthy platelet-rich plasma (PRP) of young males to 9 pure synthetic polymers, namely polyethylene, ethylene-butylene copolymer, ethylene-propylene copolymer, ethylene-ethylacrylate copolymer, ethylene-vinylacetate copolymer, ethylene-methylmethacrylate sodium ionomer, nylon 12, polyurethane, and tetrafluoroethylene-hexafluoropro-pylene copolymer ( Figure-1). Polymer pellets tested have been especially synthesized under clean conditions and were substances of known composition, free of plasticizers and... 

The determination of melting points from retention diagrams of homo-polymers has involved the use of different injected substances on poly-(ethylene terephthalate) as granules [174, 175] and fibres [176, 177], 66 nylon fibres [178], polyester fibres [179], poly(ethylene terephthalate) and poly- -caprolactam [180, 181], poly(ethylene oxide) [182,183]. Such diagrams are also known for copolymers such as ethylene-vinylacetate, ethylene-carbon oxide [184] and ethylene oxide-propylene oxide [182]. 

Poly(ethylene vinylacetate) 35-205(T ) Elvax Extrudable at low temperatures (60 °C) Excellent controlled-release polymer but nonbiodegradable... 

I. Krupa, V. Cecen, R. Tlili, A. Boudenne, and L. Ibos, "Thermophysical properties of ethylene-vinylacetate copolymer (EVA) filled with wollastonite fibers coated by silver," European Polymer Journal, vol. 44, pp. 3817-3826, 2008. 

The techniques of paraffin removal and paraffin prevention have been reviewed [810]. In particular, inhibitors for paraffin deposits are copolymers of ethylene with vinylacetate [525-527,1597] or polymers from p-nonylphenyl methacrylate and p-dodecylphenyl methacrylate [773]. These materials lower the pour point of the oil. It has been shown that for oils which differ in the content of n-paraffins and asphalt-resinous substances, it is necessary to use blends of copolymers of different compositions and molecular weights to obtain optimal efficiency. Polyacrylamide and wastes from the production of glycerol with a concentration of 400 mg/liter of oil have also been claimed to be effective as paraffin inhibitors [536]. 

Ethyl n-propylmalonate, 486 Ethyl n-propyl ketone, 340 4-Ethylpyridine, 844 Ethyl 2-pyridylacetate, 931, 932 Ethyl salicylate, 783 Ethyl sulphite, 304 Ethyl -valerate, 382, 389 Ethyl vinylacetate, 382, 389 Ethylenediamine-adipic acid polymer, 1019,1025 Ethylene glycol, 285 Ethylene glycol, monoalkyl ethers of, 170, 444... 

Figure 10. Density of different polymer latex particles as a function of centrifugation time (N = 40.000 min 1) (Y ) polyvinyl acetate (%) poly(vinylacetate-co-ethylene) (A) polystyrene (X) poly( butadiene-co-styrene) (O) poly butadiene)...

Internal plasticizers are synthesized by copolymerization of suitable monomers. Polymeric non-extractable plasticizers, mostly copolymers having substantially lower glass transition temperatures due to the presence of plasticizing ( soft ) segments such as poly(ethylene-co-vinyl acetate) with approximately 45 % vinylacetate content, ethylene-vinyl acetate-carbon monooxide terpolymer, or chlorinated PE, are available for rather special applications in medicinal articles (Meier, 1990). In this case, the performance of the internally plasticized polymers is the principal advantage. However, copolymerization may account for worse mechanical properties. A combination with external plasticizers may provide an optimal balance of properties. For example, food contact products made from poly(vinylidene chloride) should have at most a citrate or sebacate ester based plasticizers content of 5 % and at most 10 % polymeric plasticizers. 

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