To improve the hydrolysis resistant ability of trisiloxane surfactants, ethoxylated single-tail and doubletail trisiloxane surfactants of the general formulas Me 3 SiOSiMeR 1 OSiMe 3 (R 1 = (CH 2 ) 3 NHCH 2 CH(OH)CH 2 (OCH 2 CH 2 ) x OCH 3 ; x = 8.4, 12.9, 17.5, 22) and Me 3 SiOSiMeR 2 OSiMe 3 (R 2 = (CH 2 ) 3 NR 3 CH 2 CH(OH)CH 2 (OCH 2 CH 2 ) x OCH 3 ; R 3 = CH 2 (CH 2 ) y CH 3 ; x = 8.4, 12.9, 17.5, 22; y = 2, 6) were synthesized. Their structures were characterized by 1 H NMR and 13 C NMR. The surface activity and hydrolysis resistant properties of the trisiloxane surfactants prepared were also studied. The values of the critical micelle concentration of all trisiloxane surfactants prepared were at levels of 10 -5 and 10 -4 mol/L. They can reduce the surface tension of water to less than 24 mN/m. The hydrolysis resistant properties of double-tail trisiloxane surfactants are superior to those of single-tail trisiloxane surfactants. The double-tail trisiloxane surfactants 1B (x = 8.4; y = 2) and 2C (x = 12.9; y = 6) can be stable for 8 days in an acidic solution (pH 4.0) and 11 days in an alkaline environment (pH 10.0).

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