Why is the compatibility between SBS and base bitumen poor, and how can functional chemical additives improve their compatibility?



The reason for the poor compatibility between SBS and matrix bitumen is that they have great differences in chemical structure, polarity, density, molecular weight, solubility coefficient and so on. SBS is a non-polar polymer and its molecular weight is larger, while the matrix bitumen contains more polar compounds and its molecular weight is smaller.

In addition, SBS contains more double bonds, its chemical properties are more active, and its resistance to oxidation, ozone and ultraviolet aging is poor.

These differences lead to poor compatibility between SBS and the base bitumen, the two are only mechanically dispersed and wrapped, and the formed SBS modified bitumen belongs to the thermodynamic incompatible system. Functional chemical auxiliaries can improve the compatibility between SBS and base bitumen by chemical modification.


Adding functional chemical additives to SBS modified bitumen system promoted the miscibility between SBS and base bitumen due to the physicochemical effects of its solubilization, crosslinking and grafting. Functional chemical additives can make the C=C double bond in SBS and its adjacent methylene active groups in the matrix bitumen cross-linking, grafting and other chemical reactions, so that the polarity of SBS and the matrix bitumen increase, thereby improving the compatibility between them.