Improving the aging resistance of styrene‐butadiene‐styrene tri‐block copolymer and application in polymer‐modified asphalt

Thermal oxidation process of styrene-butadiene-styrene (SBS) copolymer was studied by using a variety of analytical and spectroscopic methods including thermal analysis, dynamic mechanical analysis and FTIR spectroscopy. The experimental results indicate that the thermal oxidation process of SBS is a free radical self-catalyzed reaction containing four steps (initiation, growth, transfer, and termination of the chain) with both crosslinking and scission and the latter is confirmed to be the main process. The antioxidants 1010 as scavenger of free radicals and 168 acting decomposition of hydroperoxides were used to improve the oxidation aging resistance of SBS copolymer. It has been found that synergic effect of 1010 and 168 may be the best in practice and 0.2 wt % 1010 + 0.4 wt % 168 can effectively prevent SBS from the thermal oxidation at certain temperature. Furthermore, the aging resistance of the SBS-modified asphalt was improved by addition of complex antioxidants. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 116: 754-761, 2010