Improved Thermostability of Polystyrene Prepared by a TEMPO Mediated Free Radical Polymerization-The End Group Substitution by the Thioacetic Acid Treatment

Abstract

Polystyrene was synthesized by living free radical polymerization in the presence of TEMPO (2, 2, 6, 6-tetramethylpiperidine-1-oxy). The molecular weight distribution (M_w/M_n.) of TEMPO-polystyrene was relatively low. In order to remove the TEMPO end group, TEMPO-polystyrene was treated with thioacetic acid. From the ESR analysis of TEMPO-polystyrene, strong radical signals were observed for TEMPO-polystyrene in xylene at 110°C, while no signal was observed for that after the thioacetic acid treatment. The thermal stability of TEMPO-polystyrene and the modified polystyrene was investigated by TGA. The thioacetic acid treatment was found to improve the thermal stability of the obtained polystyrene effectively.