ical having a valence of n selected from monomeric radicals of the group consisting of alkyl, cycloalkyl, and aralkyl radicals having 1 to 18 carbon atoms and polymeric radicals having the formulae: ##STR2## wherein R4 is an aliphatic radical having 1 to 18 carbon atoms, or a cycloaliphatic radical having 5 to 18 carbon atoms and a valence of r;