Thermogravimetric analysis of modified asphalt based on structure difference of styrene-butadiene-styrene block copolymer during thermal oxidation aging

Abstract

Seven styrene-butadiene-styrene block copolymer (SBS) modifiers with different styrene butadiene diblock (SB) content, styrene chain content and number average molecular weight were prepared for the preparation of modified asphalt. The effect of SBS structure on the properties of modified asphalt was investigated. The results showed that the thermogravimetric curves of SBS modified asphalt was similar to that of matrix asphalt. Its aging process included the transformation from light components to heavy components and the degradation and crosslinking of SBS itself. The mass loss rate and size of modified asphalt with different SBS structures were different. The modified asphalt with high number average molecular weight of SBS had good stability after long-term aging; The mass loss rate of SBS modified asphalt with high polystyrene segment content was significantly reduced after aging, and it had good thermal stability after short-term aging. SBS modified asphalt with more SB had poor aging resistance, and the mass loss rate increased significantly after aging.

Keywords

• styrene-butadiene-styrene block copolymer
• modified asphalt
• thermal oxygen aging
• mass loss rate
• thermogravimetric analysis