Solvent Effects on the Free Radical Polymerization of Styrene

Abstract

The free radical polymerization of styrene in various solvents has been studied. Using the rotating sector technique at 25°C rate coefficients for termination kt and propagation Ap were deter mined. The linear decrease of the former with decreasing medium fluidity shows that termination is diffusion-controlled. Values of kp decrease as the solvents used arc increased in concentration. A similar trend in Ap is observed when polymerization is initiated thermally at 60°C. The solvent effect on kt is similar to that previously recorded for methyl methacrylate, but solvents such as benzonitrile and diethyl malonatc diminish Ap of styrene while they enhance Arp for methyl metha crylate.