Polyether- and Polystyrene-Modified Polymeric Cationic Asphalt Emulsifiers: Synthesis and Performance

Abstract

Two novel polymeric cationic asphalt emulsifiers modified respectively by polyoxyethylene ether [named as polyether-type cationic asphalt emulsifier (PEAE)] and polystyrene [named as polystyrene-type cationic asphalt emulsifier (PSAE)] via free radical polymerization were synthesized by using cumene hydrogen peroxide as the initiator and 3-mercaptopropionic acid as the chain transfer agent. The investigation was conducted on the effects of polyoxyethylene ether dosage, initiator dosage, monomer molar ratio, acid/amine ratio, emulsifier dosage, and pH value on the high- and low-temperature performance of emulsified asphalt and storage stability at room temperature. The molecular structures of emulsifiers were characterized using Fourier transform infrared spectroscopy (FT-IR), and their surface activity and emulsifying performance were evaluated. The results demonstrate that the indexes of PEAE and PSAE satisfied the Chinese national standard regulations, and displayed excellent emulsifying capacity, low-temperature performance, and storage stability at room temperature. Both emulsifiers belong to slow cracking cationic asphalt emulsifiers. PEAE and PSAE can reduce the side effect of traditional small molecular cationic asphalt emulsifier on the low-temperature ductility of emulsified asphalt and improve the low-temperature performance of emulsified asphalt. PSAE was found to serve as an asphalt modifier and could improve the high-temperature performance of emulsified asphalt. The emulsified asphalt prepared using PEAE and PSAE shows promising applications in slurry seal coat construction and microsurface treatment. It is conducive to solving the problem that the traditional small molecular cationic asphalt emulsifier has large negative effect on the low-temperature performance of emulsified asphalt, which can open the window of the subsequent synthesis of polymeric cationic asphalt emulsifiers.