Thermal degradation of poly(styrene-g-acrylonitrile)

The thermal degradation of a graft copolymer in which acrylonitrile is grafted onto polystyrene has been studied by thermogravimetric analysis, TGA, thermogravimetric analysis coupled to Fourier transform infrared spectroscopy, TGA/FTIR, and cone calorimetry. The results from TGA suggest that the grafted acrylonitrile undergoes thermal degradation to give a char layer and this char offers some thermal protection to the polystyrene. TGA/FTIR results confirm that the appearance of degradation products of polystyrene are formed at a higher temperature in the graft copolymer than in polystyrene homopolymer. Analysis by cone calorimetry shows that the char which is formed in the TGA experiment under nitrogen is volatilized when the combustion reaction is performed in air. (C) 1997 Elsevier Science Limited.