Disclosed are copolymers derived from ethylene and at least two different alkyl acrylate comonomers, with or without an acid cure site-containing comonomer. The copolymers can be derived from (a) from 10 to 50 weight % of ethylene; (b) 20 to 30 weight % of a first alkyl acrylate having from 1 to 4 carbons in the alkyl group; from 35 to 45 weight % of a second different alkyl acrylate having from 1 to 4 carbons in the alkyl group; and (d) from 0 to 5 weight % of a 1,4-butene-dioic acid moiety, or anhydride or monoalkyl ester thereof; the remainder being ethylene: wherein the copolymer has a number average molecular weight (M.sub.n) above 40,000. 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 constant velocity joint boots and shaft boots, hoses, dampers, seals and gaskets. These copolymers provide improved dynamic fatigue resistance of cured compounds while maintaining an expanded operating temperature range and oil resistance. Blends of other polymers with these copolymers are also disclosed.