The Synthesis and Characterization of a Novel Cationic Asphalt Emulsifier

Abstract

A new cationic asphalt emulsifier of N,N-dimethyl-N-(3-(N',N'-dimethyl amido)-2-hydroxy propyl)- coconut oil amide propyl-1-ammonium chloride was synthesized by two steps reaction of coconut oil acyl propyl dimethyl tertiary amine (PKO), epoxy chloropropane and dimethylamine. The chemical structure of the key intermediate of N,N-dimethyl-N-(ethylene oxide-2-methylene)-coconut oil amide propyl-1-ammonium chloride was confirmed by FTIR, 1H NMR and elemental analysis. The optimum reaction condition of first step was obtained by single factor analysis: reaction time 5 h, reaction temperature 50 °C, feedstock mole ratio of epoxy chloropropane to PKO 1.05. The reaction yield is 82.15% and the epoxy value is 40.39% at the optimum conditions. The critical micelle concentration (CMC) of the asphalt emulsifier is 7.80×10-2 mol/L. The surface tension at CMC is 24.57 mN/m. The emulsifier showed excellent emulsification effect for the asphalt. The prepared bituminous emulsion had higher storage stability. The emulsifier belongs to medium-set asphalt emulsifier.