Application of Hansen Solubility Parameters to Predict Compatibility of SBS-Modified Bitumen

Abstract

Hansen solubility parameters (HSPs) of six bitumens were determined using the method of three-dimensional turbidimetric titration (Fmax). Compatibility between styrene-butadiene-styrene (SBS) block copolymer and different base bitumens were experimentally evaluated by the softening point difference and intrinsic viscosity. By comparing the difference between the HSP of SBS and bitumen with the results of compatibility evaluations, it was found that HSP has a very good agreement with results of compatibility evaluations between bitumen and SBS, which can be used to predict the compatibility of SBS-modified bitumen. Dispersive forces (δd) play a dominant role in HSP of bitumen. Polar interactions (δp) and hydrogen bonding (δh) forces have negative effects on compatibility between SBS and bitumen. Closer δd between SBS and bitumen, and lower δp and δh of bitumen improves the compatibility of SBS-modified bitumen. By comparing distribution of nonpolar components of six kinds of bitumens with dispersive forces (δd), the results showed that dispersive forces (δd) do not apparently correlate with the colloidal instability index of bitumen.