Synthesis and characterization of an amphiphilic lignin-based cationic surfactant

Abstract

Based on the application of alkali lignin polymer modification, not only can the alkali lignin green treatment be realized, but also the dependence on petroleum-based materials can be effectively reduced, and the properties of the modified polymer can be enhanced. Therefore, in this study, α-cinnamon group as the lipophilic group and diethylenetriamine group as the hydrophilic group were successfully introduced into alkali lignin to construct a lignin-based amphiphilic cationic surfactant. The lipophilic group introduced through the amine methylation reaction causes the lignin derivative to form a regular arrangement of lipophilic groups at the oil phase interface, and diethylenetriamine is introduced into the lignin through amine methylation reaction and ketoamine condensation reaction. Effectively enhance the hydrophilicity of the lignin derivative. The characterization of this lignin derivative is accomplished by different methods, such as elemental analysis, Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1HNMR) and X-ray photoelectron spectroscopy (XPS). The physical and chemical properties of the lignin derivative are tested by testing its stability in acidic solution, Zeta potential, surface tension, critical micelle concentration (CMC) and hydrophilic-lipophilic balance (HLB). Studies have shown that this amphiphilic cationic surfactant obtained by modifying alkali lignin has good performance, which means that it can be used as a W/O emulsion as an asphalt emulsifier, wetting agent, etc.