Catalytic oxidative polymerization of vinyl monomers using cobalt phthalocyanine complex and an exploratory investigation on the polymerization of vinyl acetate

Abstract

This is the first report on the oxidative polymerization of vinyl monomers using cobalt(II) phthalocyanine pyridine {Co^IIPc(Py)} complex. The mechanism of polymerization is described and it has been supported from the kinetic data, UV-vis, ESR and 1^H NMR studies. It is found that the rate of polymerizations (R_p) and number-average molecular weights (M_n) of the vinyl polyperoxides are higher for Co^IIPc(Py) catalyzed polymerization compared to the usual free radical, AIBN, initiated polymerization. This is supported by their activation energy of initiation (E_i) and total activation energy (E_a) of polymerization. The peroxide macroinitiator has been used for the polymerization of vinyl acetate. The polymerization obeys classical kinetics. The K² values of the peroxide macroinitiator has been determined, which reveals that it can also be used at higher temperature for the polymerization compared to monomeric peroxide initiator, benzoyl peroxide. The "active" poly(vinyl acetate) has also been synthesized, which contains peroxy segments at the chain ends.