Preparation And Properties Of Grafted SBS Modified Asphalt

SBS modified asphalt has been used widely for the excellent performance. Unfortunately, the SBS modified asphalt was showed the lower compatibility and stability by high temperature storage, the application of the SBS modified asphalt in road performance and many industrial areas were limited. Therefore, it is very significative for the road performance to improve the compatibility of SBS modified asphalt.In this paper, methyl methacrylate grafted SBS (MMA-g-SBS),acrylic acid grafted SBS(AA-g-SBS) and maleic anhydride grafted SBS(MAH-g-SBS) were prepared by solution graft polymerization. The grafted degree (DG) of graft SBS modifier was investigated and structure was characterized by Fourier transform infrared spectroscopy (FTIR). This experiment studied mainly on the effects of the physical properties,microstructure,compatibility,rheological properties and ageing properties of grafted SBS modified asphalt by changing grafting degree.The result showed that, with the increase of grafting degree, ductility and elastic recovery of grafted SBS modified asphalt obviously increased. Softening point,viscosity,penetration and high temperature storage stability was improved of MAH-g-SBS modified asphalt; Softening point and viscosity were decreased of MMA-g-SBS and AA-g-SBS modified asphalt.The results with isolation test and fluorescent microscope analysis showed that: with the increase of grafting degree, compatibility of grafted SBS modified bitumen obviously increased and the high temperature storage stability was improved by isolation testing and fluorescence microscopy.The dymamic shear rheometry parameter (DSR) showed that: compared to SBS modified asphalt, grafted SBS modified asphalt exhibit higher complex modulus (G~*), rut foctor (G~*/sinδ) at the same temperature, which display greatly improve their rutting resistance at high temperature.The ageing properties of grafted SBS modified asphalt were evaluated by the Thin Film Oven Test (TFOT), the pressure ageing vessel (PAV), long-term ultraviolet(UV) aging. The experiment results showed that better anti-ageing of grafted SBS modified asphalt than pure SBS, and MAH-g-SBS modified asphalt than MMA-g-SBS and AA-g-SBS. This is because the C=C double bond was decreased with graft copolymer, and the hot degradation of SBS chains was reduced. The anti-ageing property of grafted SBS modified asphalt was improved. At the same of grafting degree, the least double bonds of MAH-g-SBS with tha all grafting modified was contained, so the better anti-aging properityof MAH-g-SBS modified asphalt.