POSTPOLYMERIZATION EFFECT ON MOLECULAR-WEIGHT DISTRIBUTION GENERATED BY PULSED-LASER RADICAL POLYMERIZATION

The postpolymerization effect on molecular weight distributions (MWDs) and on the Pulsed Laser Polymerization (PLP) technique for evaluation of kinetic constants is investigated. General expressions for moments are derived for a polymerization scheme that contains the reactions o f chain initiation, propagation, and termination by recombination or d isproportionation, under polymerization initiation by an arbitrary seq uence of radiation pulses. The results of calculation of MWDs and of t he weight-average degree of polymerization <((P)over bar (W))> for met hyl methacrylate are presented. It is shown that the <(P)over bar (W)> value strongly depends on postpolymerization. A new method for determ ining the rate constants of chain propagation and chain termination fr om a single experiment by polymerization with packets of laser pulses is presented.