Acrylic Elastomers

Abstract

AbstractAcrylic elastomers (ACMs) are specialty rubbers whose structure shows both the presence of a saturated backbone, which is responsible for the high heat, and oxidation resistance, and the ester side groups, which contribute to the marked polarity of this elastomer family. The first commercial ACMs were produced and introduced in the market in the United States in the 1940s.The base monomers of modern acrylic rubbers are ethyl acrylate, butyl acrylate, and 2‐methoxyethyl acrylate. These monomers are polymerized by free‐radical catalysts in aqueous suspension and emulsion polymerization. In order to facilitate vulcanization, proper reactive monomers are copolymerized with alkyl and/or alkoxyalkyl acrylates. A large variety of cure‐site monomers has been proposed, but only a few have achieved commercial significance. Two of the most important classes are labile chlorine‐containing monomers and epoxy/carboxyl‐containing monomers.Acrylic elastomers can be tailor‐made to meet certain performance requirements. The influence of monomer composition on oil resistance and low temperature flexibility has been studied both from the theoretical and experimental point of view. ACMs, as most elastomers, have to be propertly formulated in order to supply valuable performance. Reinforcing filler(s) and other typical rubber ingredients and additives are required. Acrylic elastomers have found commercial applications mainly in automotive non‐tire applications such as: seals, gaskets, valve stem oil deflectors, hose and hose linings, wire and cable jacketing, noise control, and vibration damping.