Relations between thermal degradations of SBS copolymer and asphalt substrate in polymer modified asphalt

摘要

The variations in the chemical characteristics of asphalt constituents and styrene-butadiene-styrene tri-block copolymer (SBS) in the polymer modified asphalt (MA) during degradation process should be clarified to design the effective recycle method of MA. In this study, the chemical characteristics of MA during thermal degradation process were studied in detail. The effects of the period of thermal degradation of MA, the content of as-phaltene constituent in MA and the kind of substrate instead of the straight asphalt were discussed from the yield and thermogravimetry (TG) curves of four constituents in MA and the molecular weight distribution of SBS. As a result, the yield of polar constituent (asphaltene) increased gradually with decomposition of SBS during thermal degradation of MA. Decomposition of SBS was enhanced by the low molecular weight substrate, such as aromatic oil. On the other hand, decomposition of SBS was inhibited by MA of high asphaltene content.