Photodegradation of polystyrene/rubber waste blends compatibilized with SBS copolymer

Abstract

The aim of this study was to evaluate the photooxidative stability of polystyrene/vulcanized rubber waste blends, compatibilized with styrene–butadiene–styrene. High-impact polystyrene (HIPS) was used for comparison. All samples were exposed to ultraviolet (UV) radiation for 8 weeks and then analyzed for mechanical properties (tensile and impact), infrared spectroscopy, colorimetry, and optical microscopy. It was observed that the mechanical behavior of the photodegraded samples was a consequence of the superficial chemical modification, which was accompanied by defect formation. The most sensitive properties to aging were the impact strength and elongation at break, with HIPS being the least photostable material. The penetration depth of the UV radiation was lower for the core of the blends than for the HIPS. This finding indicated that the protective additives and mineral fillers (titanium dioxide and talc, respectively), which are present in the rubber residue, minimized the transmittance of radiation into the blends. Consequently, losses in the mechanical properties were minimized.