one or more activating cationic organo group-4 catalyst(s) or an organic Lewis acid and one or more monomer(s), said one or more of each monomer(s) of each reactant stream, independently, having the formula: ##STR15## wherein R1 is hydrogen or an alkyl group having from 1 to 4 carbon atoms and R2 is an alkyl or a cycloalkyl group having from 1 to 10 carbon atoms, or wherein R2 is R5 -silyl-R6 or R