Study on the synergistic effect of the binary compound system of cardanol sulfonate

Abstract In the present work, the anionic biomass surfactant cardanol sulfonate (CDS) was compounded in different molar fractions ( α 1 ) with the commonly used amphoteric surfactant lauryl amidopropyl betaine (LAB) and the nonionic surfactant alkyl glycoside (APG), respectively. By measuring the surface tension of the binary compound system, the relationship between the surface chemical properties of the compound system and α 1 was investigated, and then the synergistic parameters and thermodynamic parameters of the compound system were calculated. The results showed that both CDS/LAB and CDS/APG systems exhibited non-ideal mixing behavior. The CDS/LAB compound system has the best synergistic effect when the two components were mixed in a 1:1 molar ratio, corresponding to a CMC of 3.06 × 10 −4 mol L −1 and a γ CMC of 32.60 mN m −1 . The formation of mixed micelles was a spontaneous exothermic process driven by enthalpy. The CDS/APG compound system at the molar ratio of n (APG): n (CDS) = 9:1 has a more significant synergistic effect, corresponding to a CMC of 1.13 × 10 −4 mol L −1 and a γ CMC of 29.10 mN m −1 . The application performance of the compound systems was the best at the optimal molar ratio, which confirms the existence of synergistic effect in the compound systems.