Solvent effects on the coupling processes of polystyryl radicals

Abstract

The molecular weight distributions of polystyrene prepared in various solvents at 60 °C showed broadening with increasing solvent viscosity, whereas the effects of solvent power were not conspicuous. Simulations of polymerization reactions with several models showed that the coupling probability of polystyryl radicals is not independent of chain length at 60 °C and that the chain length dependence becomes apparent with increasing solvent viscosity. These results were discussed in terms of the dynamical behavior of polymer radicals in solution and it was tentatively concluded that the chain length dependence of coupling probability of polystyryl radicals originates mainly from the hydrodynamic interactions between polymer segments.