Inhibiting wax precipitation in asphalt binder from perspective of dispersing asphaltenes

Abstract

In cold region, crystalline wax can continuously precipitate from the asphalt binder distilled from the crude oil after cooling, which seriously damages cracking resistance of the asphalt pavement at the low-temperature. Few researchers have developed wax inhibitors (WIs) to inhibit wax crystallization in the asphalt field and existing WIs only focus on direct interaction with wax crystals. Herein, the ionic liquid (IL) modified with different commonly used concentrations of graphene oxide (GO) (0.3 %, 0.6 %, 0.9 %, 1.2 % IL) was synthesized as novel WI through in situ polymerization from the new perspective that the dispersed asphaltenes could inhibit wax crystal network. The successfully synthesized nanocomposites at the optimal content (900 ppm) and component (IL-0.6 %GO) reduced wax precipitation temperature (WPT) of asphalt binders by 14 °C, and the synergistic effect of IL and GO in the nanocomposite has most significant effect on wax inhibition than the existing WIs (IL and Poly(methyl methacrylate) (PMMA)). IL indirectly inhibits wax crystal network by dispersing asphaltenes through π-π interactions and charge transfers from IL to asphaltenes, which is superior to the direct reduction of wax crystals by PMMA. Therefore, it is very effective and promising to synthesize nanocomposites as wax inhibitors from the new perspective of dispersing asphaltenes compared with existing WIs to improve the low-temperature performance of asphalt.