Other Organic Vinyl Ester Polymers

Of the higher vinyl ester homopolymers only poly(vinyl propionate) is currently believed to be of commercial value, being marketed as Propiofan (BASF) for surface coating application where greater alkali resistance is possible than with the normal vinyl acetate based copolymers. 

Whilst vinyl acetate is reluctant to copolymerise it is in fact usually used today in copolymers. Two of particular interest to the plastics industry are ethylene-vinyl acetate (Chapter 11) and vinyl chloride-vinyl acetate copolymers (Chapter 12). In surface coatings internal plasticisation to bring the Tg to below ambient temperatures and thus facilitate film forming is achieved by the use of ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and dialkyl maleates and fumarates. 

DAVIDSON, R.L., and srmG, m.. Water-soluble Resins, Reinhold, New York (1962) 

DELZENNE, G.A., Encyclopaedia of Polymer Science and Technology, Supplement, Vol.l, p.401, Wiley, New York (1976) 

LEONARD, E. c. (Ed.), Vittyl and Diene Monomers (High Polymers Series Vol. 24), Wiley-Interscience, New York (1971) 

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As shown in Table 2.7, the coefficient of chemical resistance of RubCon is 1.0 for water, 0.81-0.95 for all mineral acids (exception is KCI = 0.69 for 36% solution of hydrochloric acid), 0.82-0.95 for organic acids, 0.82-0.91 for alkalis, 0.88 for solvents and petroleum products, and 0.84-0.86 for solution of salts. The analysis of experimental data has shown that RubCon offers universal chemical resistance many times higher than ordinary Portland cement concrete and surpasses the chemical resistance of polyester, polyepoxy, and vinyl ester polymer concrete. It is worth noting that penetration depths of 5% nitric and 36% solution of hydrochloric acids into RubCon sample bodies were 3, 4, and 5.1 mm, respectively the penetration ability of these acids is higher as compared with other corrosive environments. 

The polymerization of vinyl acetate can be carried out in a wide variety of solvents in which both the monomer and polymer are soluble. Azo, peroxide, and hydroperoxide initiators as well as many other organic-soluble initiators can be used. Solvents with low chain-transfer constants, such as benzene, toluene, acetic acid, acetic anhydride, acetone, and cyclohexanone, are required to obtain reasonably high molecular weights. Solution techniques are especially convenient for the laboratory preparation of poly(vinyl esters) and are used in certain commercial applications in which the polymers are sold directly as solutions. 

From elementary organic chemistry, we know that the positions and hence reactivities of the electrons in unsaturated molecules are influenced by the nature, number, and spatial arrangement of the substituents on the double bond. As a result of these influences, the double bond reacts well with a free radical for compounds of the types CHj = CHY and CHj = CXY. These compounds constitute the so-called vinyl monomers where X and Y may be halogen, ally l, ester, phenyl, or other groups. It must, however, be noted that not all vinyl monomers produce high polymers. In symmetrically disubstituted double bonds (e.g., 1,2 disubstituted ethylenes) and sterically hindered compounds of the type CHj = CXY, polymerization, if it occurs at all, proceeds slowly. 

Benzyl alcohol [100-51-6] is miscible with organic solvents apart from aliphatic hydrocarbons. It dissolves cellulose esters and ethers, fats, oils, alkyd resins, natural and synthetic resins, and colorants. Polymers—with the exception of lower poly(vinyl ethers) and poly(vinyl acetates)—are not dissolved. Small amounts of benzyl alcohol improve the flow and gloss paints, delay the evaporation of other solvent components, and have a plasticizing effect in physically drying paints. It is used in ballpoint pen inks. Benzyl alcohol reduces the viscosity in two-pack epoxy resin systems. 

Ethyl amyl ketone, a high boiling ketone, is a colorless, stable liquid with a mild pleasant odor. It is compatible with alcohols, ethers, other ketones and organic liquids, and in addition, exhibits low water miscibility. Ethyl amyl ketone s high solvency for cellulose esters, vinyl polymers... 

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