A polymeric adduct support having units of the formula ##STR15## wherein R1 is H or CH3,R2 and R3 each independently is an alkyl group having 1 to 14 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, an aryl group having 5 to 12 ring atoms, an arenyl group having 6 to 26 carbon and 0 to 3 S, N, and nonperoxidic O heteroatoms, or R2 and R3 taken together with the carbon to which they ar