Disclosed are copolymers derived from copolymerization of from about 50 to about 70 weight % of methyl acrylate; from about 0.5 to about 5 weight % of 1,4-butene-dioic acid moieties, or anhydrides or monoalkyl esters thereof; the remainder being ethylene, wherein the copolymer has a number average molecular weight from about 40,000 to about 65,000 and a melt index from about 1 to about 6 g/10 minutes. Also disclosed are compounded compositions comprising these copolymers, and cured compositions (i.e., vulcanizates) as well as rubber articles formed from these compounded compositions, such as hoses, dampers, boots, seals, and gaskets for automotive and nonautomotive applications. Blends of other polymers with these copolymers are also disclosed.