Synthesis and application of nonionic Gemini surfactants based on grape seed oil

A series of vegetable oil-based nonionic Gemini surfactant (GPNGS) was prepared using grape seed oil and polyethylene glycol monomethyl ether (350, 550, 750) as the primary raw materials. The chemical structures of different types of GPNGS were characterised by Fourier Transform–infrared spectroscopy, elemental analysis, proton nuclear magnetic resonance and carbon-13 nuclear magnetic resonance. The critical micelle concentration (CMC) of GPNGS with different polyoxyethylene chain lengths was measured using the Wilhelmy ring method (CMC: ca. 1.4 × 10⁻⁴ to 5 × 10⁻⁴ mol/L). The results of wettability testing showed that the contact angle of GPNGS on polyamide film was ca. 46-49°. In addition, the interaction of surfactants with acid dyes was also investigated. The ultraviolet spectrum showed a balance between dyes, surfactants and the dye/surfactant complex. Next, the GPNGS was used as a nylon 66 acid dye levelling agent. After adding 0.2 mmol/L of surfactants, the standard deviations (S(λ)) of nylon 66 dyeing decreased from 0.084 to ca. 0.036-0.044, exhibiting a good levelling effect.