Material BehaviourPhoto-degradability of ketone modified PS/HIPS blends

The present work studies the degradability of PS/HIPS blends (50/50%, w/w) modified with different amounts of acetophenone and benzophenone (2.5 and 5%), aiming at the improvement of its decomposition when exposed to natural environment. Suitable characterization techniques, such as infrared and UV-Vis spectroscopy, viscosimetry and tensile tests were used to monitor the extent of the degradation. Evidence for the formation of hydroperoxides and carbonyl groups, occurrence of chain scission and loss of mechanical properties was achieved, being higher for samples with benzophenone. Further, it was also observed that for the same ketone level, benzophenone caused higher changes of mechanical properties, which is in agreement with the decrease of molecular weight observed. Thus, the photo-degradability of PS/HIPS blends could be enhanced by adding this type of chemical compound.The results obtained are presented and discussed aiming at the optimization of the degradation of PS/HIPS when exposed to the natural environment.