Synthesis and photochemistry of monodisperse oligomeric-polymeric photoinitiators

Monodisperse polystyrene with a photoinitiator end group was prepared using living free radical polymerization. Nanosecond pulsed laser irradiation was used to generate the oligomeric/polymeric radicals, and the relaxation time constants of the electron spin polarized signal were measured using Time-Resolved Fourier-Transform EPR (TR FT EPR). The preliminary results demonstrate the applicability of this method in the direct experimental study of the properties of the oligomeric/polymeric radicals. This method is expected to allow the study of the chain length dependence of free radical polymerization kinetics with improved accuracy and a larger range of concentration and chain length.