Polyvinylacetate

Polyvinylacetate in a partially saponified form may perform function of its own plasticizer. In some other applications, it is plasticized by the following plasticizers  

This polymer requires only small additions of plasticizers. Plasticizers in most instances must be compatible with water-based systems and enviromnent-friendly. 

The critical concentration of micelle formation. Goo, is a limiting value of absorption, Gm, calculated from equation  

Knowledge of the critical concentration of the micelle formation is useful in calculation of the surface area occupied by one plasticizer molecule  

Investigation of the radiolysis of carefully purified Mowilith-90 was recently performed by Geuskens etal. [352, 353]. The yields for cross- 

RADIOCHEMICAL YIELDS FOR THE RADIOLYSIS OF POLYVINYLACETATE AT ROOM TEMPERATURE [352, 353] 

The evolution of carbon monoxide, carbon dioxide and methane must be ascribed to side-group scission according to reactions (35) and (39). Methane formation is due to hydrogen abstraction by methyl radicals but, since the yield of methane is lower than the yield of carbon monoxide plus carbon dioxide, only a fraction of the methyl radicals produced are able to escape the cage. Most of them recombine with macroradicals according to reactions (38) and (41). Chain scission occurs according to 

On the other hand, crosslinking can be assigned to the recombination of macroradicals produced in reactions (35) and (39) with those formed by abstraction of a tertiary hydrogen from the main chain by the methyl radicals, viz. 

Network formation in the radiolysis of poly vinylacetate can thus be visualized as resulting from 

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The surface energy of fibers is closely related to the hydrophilicity of the fiber [38]. Some investigations are concerned with methods to decrease hydrophilicity. The modification, of wood cellulose fibers with stearic acid [43] hydrophobizes those fibers and improves their dispersion in polypropylene. As can be observed in jute-reinforced unsaturated polyester resin composites, treatment with polyvinylacetate increases the mechanical properties [24] and moisture repellency. 

Polyvinylacetate. A thermoplastic primarily used as a binder in non-metallic cartridge cases (see Mil Spec below)... 

Polyvinylacetate aq emulsion for use as a binder in non-metallic cartridge cases is covered by US Mil Spec, Polyvinyl Acetate Aqueous Emulsion (PAAE) (For use in Ammunition) , MIL-P-50855(MU) (31 March 1971). The requirements and criteria are in Table 1... 

FIGURE 24.4 Master curves of the local segmental relaxation times for 1,4-polyisoprene (-y = 3.0) 1,2-polybutadiene (7=1.9) polyvinylmethylether (7 = 2.55) polyvinylacetate (7 = 2.6) polypropylene glycol (7 = 2.5) polyoxybutylene (7 = 2.8) poly(phenyl glycidyl ether)-co-formaldehyde (7 = 3.5) polymethylphe-nylsiloxane (7 = 5.6) poly[(o-cresyl glycidyl ether)-co-formaldehyde] (7 = 3.3) and polymethyltolylsiloxane (PMTS) (7 = 5.0) [15 and references therein]. Each symbol for a given material represents a different condition of T and P. 

Polyvinylacetate Polymethylmethacrylate Propylene carbonate o-Terphenyl Phenyl salicylate... 

C13-0089. Chewing gum is mostly polyvinylacetate. The monomer used to make chewing gum is vinyl acetate ... 

Polytetrafluoro ethylene Polyurethane foam Polyurethane foam, fire retardant Polyvinylacetate... 

The most stable resin for many of our purposes has proven to be a copolymer of ethyl methacrylate and methyl acrylate. This comes as little surprise the Rohm and Haas Company has for years sold a durable resin based on these two monomers, Acryloid B-72 (6,28). We have also prepared polymers of similar physical properties based on methyl methacrylate and ethyl acrylate and have found that their behavior is practically the same - the methyl and ethyl groups apparently do not become seriously involved in crosslinking. As reported elsewhere( 23), rather than crosslink, Acryloid B-72 tends to chain break under visible and near-ultraviolet radiation, although at a very slow rate. Polyvinylacetate is another polymer used in the care of museum objects that tends more to chain break than crosslink under these conditions(23), but it is not our purpose to discuss its properties at this time. 

A-max = 525 run) has allowed both a determination of the depolymerisation rate and the number of break points (i. e. 2 DPPH molecules per bond breakage). Evidence for the formation of macroradicals in the degradation of polymethyl methacrylate, polystyrene and polyvinylacetate has also been provided by Tabata [63] using spin trapping and esr techniques. Taranukha [64] has also used spin traps to study the degradation of aqueous polyacrylamide. 

Polyvinyl chloride can be shaped into clear, soft flexible tubing and sheets with the aid of using plasticizers such as diethylhexyl phthalate (DEHP). Polyvinyl chloride resins are used for children s toys, automobile seat covers, and for catheters used for intravenous transfusion of blood and nutrients in hospitals and homes. When DEHP was suspected of leaching out of the products, and of being a carcinogen, substitutions were developed with polyvinylacetate and polyethylene. However, these substitutes are not yet totally satisfactory, as they cannot be steam sterilized, and they are not as clear and flexible as PVC. 

When tested in other polymers, maleimides did not affect the rate of cross-linking in polydimethylsiloxane, polyisobutylene, and polyvinylchloride. In polyethylene, the addition of 5 wt.% of m-phenylene dimaleimide increased the G(X) from 1.8 to 7.2. In the polyvinylacetate the effect was even more pronounced the dose for gelation was reduced by about a factor of 50. Contrary to the cross-link enhancing effect found for m-phenylene dimaleimide, cross-linking was retarded in polyvinyl acetate by the addition of monomaleimides. When analyzing the mechanism of the reaction it was concluded that monomaleimides are not expected to affect cross-linking in saturated polymers. ... 

The dye used in the fabrication of the IR DIP disk was a carbocyanine (3,3 -diethyl-12-acetyl-thiatetracyanine perchlorate) it is designated NK1748 and was obtained from the Japanese Research Institute for Photosensitizing Dyes Co. Ltd. Its molecular structure is shown in Figure 12 along with its absorption spectra in methanol and in a thin solid film of polyvinylacetate... 

Figure 12. Molecular structure and absorption spectra of NK1748 in methanol solution and in polyvinylacetate.

Figure 15. Influence of the Polyester Yellow dye film absorbance and polymer binder material on the marking threshold energy. PnBMA = poly(n-butyl methacrylate) PiBMA = poly(isobutyl methacrylate) PS = polystyrene PsBMA = poly (sec-butyl methacrylate) PVB = polyvinylbutyl PMMA = polymethyl methacrylate PVAC = polyvinylacetate, S-iBMA = poly(styrene-co-isobutyl methacrylate), PC = polycarbonate S-AN — poly(styrene-co-...

Schonecker DR, DeMerlis CC, Borzelleca JF. Evaluation of the toxicity of polyvinylacetate phthalate in experimental animals. Food Chem Tox 2003 41 405. 

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