Improved properties of polystyrene-modified asphalt through dynamic vulcanization

Storage-stable polystyrene (PS)-modified asphalt has been successfully prepared in the presence of linear styrene–butadiene–styrene triblock copolymer (SBS) through dynamic vulcanization. The vulcanization characteristics of the asphalt/PS/SBS/sulfur blends were studied using a strain-controlled rheometer. At temperatures from 140 to 180°C, the curing rate of the blends increases significantly with increasing temperature. A suitable processing temperature is between 170 and 180°C for the sake of good mechanical and thermal stability properties. The physical properties, including softening point, penetration, and ductility at low temperature of the modified asphalt through dynamic vulcanization were compared to that of modified asphalt without sulfur. The storage stability of the PS-modified asphalt was effectively improved in the presence of SBS through dynamic vulcanization. The morphology and rheological properties of the modified asphalt were also investigated using an optical microscope and a dynamic shear rheometer, respectively. The morphology was compared between the pure PS-modified asphalt, the PS/SBS-modified asphalt, and the PS/SBS/sulfur-modified asphalt, which indicated that the compatibility and high-temperature storage stability of the PS-modified asphalt were improved significantly in the presence of SBS through dynamic vulcanization.