Infrared and thermogravimetric studies of thermal degradation of polystyrene in the presence of ammonium sulfate

Thermal and thermo-oxidative degradation of polystyrene (PS), in the presen ce of ammonium sulfate, was studied with thermogravimetry (TG) and infrared spectroscopy (IR). Thermogravimetry results indicated that ammonium sulfat e accelerated thermal degradation in nitrogen but delayed thermo-oxidative degradation of PS in air. IR analysis of tetrahydrofuran extracts, from the samples degraded at 340 degrees C, and of residues after thermal treatment at 340 degrees C in a muffle furnance, showed that the acceleration of the rmal degradation and the suppression of thermo-oxidative degradation were d ue to sulfonation and oxidation of ammonium sulfate and its decomposition p roducts, and formation of unsaturated structures in the PS chain. (C) 1998 Elsevier Science Limited. All rights reserved.