d aryl. cycloulkyl substituted cycloulkyl. aralkyl, substituted aralkyl, alkyl and substituted alkyl groups containing l to 4 carbon atoms: and A is a polyvalent organic moiety free of unsaturated groups in conjunction with the reactive ene or yne groups in X. Thus A may contain cyclic groupings and minor amounts of hetero atoms such as N, S, P or 0, but contains primarily carboncarbon, carbon-oxy