Development Of Novel Grade Of SBS For Asphalt Modification

SBS has many advantages such as good solubility to asphalt, stability, process ability, and reasonable price, etc. It is widely used to the industry of modified asphalt. Considering many kinds of structure of SBS and the different composition of asphalt, each grade of SBS should combine with proper asphalt to have the perfect modifying effect. It is necessary to develop more grades of SBS asphalt modifier to meet the market need and produce more competitive product for Beijing Yanshan Petrochemical Corporation (BYPC).There are only two grades of SBS-modified asphalt in BYPC, they are GuoChang No.1 and SBS 4303. But both of them have a low modifying ability to some asphalt, which cannot meet the demand for modified asphalt in road and only can be applied in a very limited field. The purpose of this article is researching related literature and analyzing the influence factors of the product physical character, improving the production process, and developing a new grade of asphalt modifier SBS1301-2 which is demanded in the market. It shows that the rubber solution blending, the number-average molecular weight and the distribution in rubber solution in the single reactor are important factors which influence melt flow index of SBS1301. Instead, the monomer concentration, reaction condition and the feeding method of tetrahydrofuran have little influence on the tensile strength. when the molecular weight of SBS1301 is almost the same, the tensile strength of SBS block copolymer improves with the increasing amount of the styrene; when the block ratio of SBS1301 is almost the same, the tensile strength of SBS block copolymer improves with the increase of the peak position molecular weight at the beginning, then when the tensile strength reaches a specific data, the value will decrease; the existence of small amount high molecule and gel leads to the decrease of tensile strength of SBS block copolymer. In conclusion, adjusting the amount of the styrene and molecular weight can improve the character of SBS1301 prominently.By adjusting the amount of the styrene and molecular weight rationally, the asphalt modifier SBS1301-2 has been developed successfully. The estimation and the test to the SBS1301 feed, the store stability of modified asphalt and the construction on site show that SBS1301 can be applied to modified asphalt in road with good modifying effect and application performance, its some performances are higher than those of the same kind of domestic product, it can meet the demand of the customers well.