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Acrylic Elastomers

المؤلف:  A. Ravve

المصدر:  Principles of Polymer Chemistry

الجزء والصفحة:  p375-376

2026-02-02

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Acrylic Elastomers

Polymers of lower n-alkyl acrylates are used commercially to only a limited extent. Ethyl and butyl acrylates are, however, major components of acrylic elastomers. The polymers are usually formed by free-radical emulsion polymerization. Because acrylate esters are sensitive to hydrolysis under basic conditions, the polymerizations are usually conducted at neutral or acidic pH. The acrylic rubbers, like other elastomers must be cross-linked or vulcanized to obtain optimum properties. Cross-linking can be accomplished by reactions with peroxides through abstractions of tertiary hydrogens with free radicals:

Another way to cross-link acrylic elastomers is through a Claisen condensation:

The above illustrated cross-linking reactions of homopolymers, however, form elastomers with poor aging properties. Commercial acrylic rubbers are, therefore, copolymers of ethyl or butyl acrylate with small quantities of comonomers that carry special functional groups for cross-linking. Such comonomers are 2-chloroethylvinyl ether or vinyl chloroacetate, used in small quantities (about 5%). These copolymers cross-link through reactions with polyamines.