aryl, C7-C15 aralkyl, C7-C15 alkaryl, or alkenyl group of 1 to 40 carbons or -C(0)-X wherein X is C1-C30 alkyl, C6-Ci4 aryl, C7-C15 aralkyl, Ci- Ci5alkaryl, or an alkenyl group of 1 to 40 carbons, or a mixture thereof; R31 is a divalent group selected from alkylene radical of 1 to 40 carbon atoms which may be interrupted with arylene group of 6 to 18 carbons or an alkylene group containing unsatur