An analytical investigation of the thermal degradation of a cation-exchange resin — part 2

Abstract

In part 1 of this study the thermal degradation of an ion-exchange resin was followed by laser microprobe mass analysis (LAMMA), which revealed the processes of desulphonation and polymer chain degradation. Also, an initial gas chromatography/mass spectrometry (GC/MS) analysis identified 1,3-diphenylpropane as being a major degradation product. Unsaturated organic degradation products were not particularly evident. In this article the identification by GC/MS analysis of the organic thermal degradation products of the same ion-exchange resin are presented, permitting the LAMMA technique to be used alone in order to follow the resin's degradation processes. All the information obtained has led to the proposal of an approximate thermal degradation mechanism for this resin, which is presented here. The resin is a sulphonated copolymer of polystyrene and divinylbenzene. The organic degradation products are formed from pyrolysis at 300 °C over 24 h. During pyrolysis the resin is in an aqueous environment.