Synthesis and Properties of Sodium Salts of Sulfonated Cardanol Polyethoxylates

Abstract Sodium salts of sulfonated cardanol polyethoxylates (NSF–nSO, with n = 3 or 6 for the average ethylene oxide number) were synthesized using cardanol polyethylene oxides from renewable cardanol and sodium isethionate as reagents. The surface tension, interfacial tension (IFT), foaming, wetting ability and emulsifying ability of NSF–nSO were investigated. It was found that there was no significant difference between NSF–3SO and NSF–6SO in the critical micelle concentration (CMC), but the surface tension of NSF–3SO at CMC was lower than that of NSF–6SO. The diffusion coefficient (D eff ) decreases with the increase of the NSF–nSO concentration. The IFT between NSF–3SO solution and dodecane is lower than that of NSF–6SO at studied salt concentrations. The foaming, wetting and emulsifying abilities of NSF–3SO are better than those of NSF–6SO. The above results show that NSF–3SO has better surface/interface activity than NSF–6SO.