POLYMERIZATION OF METHACRYLIC-ACID AND ACRYLONITRILE BY PARA-NITROBENZYL TRIPHENYL PHOSPHONIUM YLIDE

Radical polymerization of methacrylic acid (MAA) and acrylonitrile (AN) in the presence of p-nitrobenzyl triphenyl phosphonium ylide (p-NBTPy) in dimethyl sulphoxide at 65 +/- 0.1-degrees-C under inert atmosphere was investigated by dilatometry. The ylide failed to initiate the polymerization, but significantly accelerated the rate of polymerization. An interesting feature is that the average polymer molecular weight (MBAR upsilon) is a direct function of (p-NBTPy). The radical polymerization of MAA follows ideal kinetics since calculated monomer and initiator (AIBN) exponents are unity and 0.5, respectively. However, the AN system follows non-ideal kinetics due primarily to radical termination and transfer reactions. The energy of activation, in the presence of p-NBTPy, is low. The accelerating effect of p-NBTPy has been attributed to decreased termination because the ylide did not affect the rate of decomposition of AIBN, as well as form a complex with monomer(s).