A curable composition of claim 3; wherein each R is hydrogen or an alkyl or aromatic group having from 1 to about 6 carbon atoms, each R' is a divalent hydrocarbyl group having from 1 to about 5 carbon atoms; each R is independently hydrogen or a hydrocarbyl group having from 1 to about 5 carbon atoms and Z is chloride, bromide, phosphate, fluoborate, or acetate.acetic acid complex.