丁炔二醇醚改性有机硅表面活性剂的制备及构效关系

Preparation and structure-activity relationship of butynediol ether modified organosilicon surfactants

以八甲基环四硅氧烷和四甲基环四硅氧烷为单体、六甲基二硅氧烷为封端剂,在酸性条件下经缩聚反应制得了不同硅氧烷链长(简称链长,m+n)和硅氧烷链节与含氢硅氧烷链节比(简称链节比,m/n)的含氢聚硅氧烷(LPMHS);接着,LPMHS与丁炔二醇二乙氧基醚(BEO)进行氢化硅烷化反应,制得了一系列丁炔二醇醚改性有机硅表面活性剂(PSi-EO)。采用FTIR和^(1)HNMR对PSi-EO进行了表征,测试了其性能,探究了其结构与性能之间的构效关系。结果表明,当m/n=4时,随着m+n的增加(5~30),PSi-EO消泡能力持续降低,抑泡能力呈先升高后降低的趋势,当m+n=20时抑泡时间为16.53 min,而其水溶液的临界胶束浓度不断减小、最低表面张力不断提高,PSi-EO水溶液的最低表面张力由链长决定;当m+n=20时,随着m/n的减小(18/2~14/6),PSi-EO的消泡能力增加,而抑泡能力降低,m/n=17/3时的PSi-EO具有较优的消/抑泡能力(消泡时间71.28 s;抑泡时间19.34 min);随着m+n的增加和m/n的降低,PSi-EO分子链延长且亲水基接枝量增加,其接触角也随之增大,润湿能力降低;PSi-EO在水溶液中均能形成球形胶束,较小的聚集体可自组装形成大而复杂的聚集体,平均粒径为100~300 nm,其聚集体形态与其链长和链节比无关;PSi-EO分子更倾向吸附于气液界面,可快速降低分子附近泡膜的表面张力,从而促使气泡破灭。

A series of hydrogen-containing polysiloxanes(LPMHS)with different siloxane chain lengths(short for chain length,m+n)and ratios of siloxane links to hydrogen-containing siloxane links(short for chain link ratio,m/n)were prepared by polycondensation under acidic condition using octamethylcyclotetrasiloxane and tetramethylcyclotetrasiloxane as monomers,and hexamethyldisiloxane as terminating agent.Subsequently,a series of butynediol ether(BEO)modified organosilicone surfactants(PSi-EO)were prepared from hydrogensilanization of LPMHS,characterized by FTIR and ^(1)HNMR,analyzed for their properties,and evaluated for the structure-activity relationship.The results showed that when m/n=4,with the increase of m+n(5~30),PSi-EO exhibited a decrease in the antifoaming ability and the critical micelle concentration of its aqueous solution,a trend of increase first and then decrease in the foam-suppressing ability with the highest value reached when m+n=20(foam-suppressing time 16.53 min),and an increase in the minimum surface tension with the lowest surface tension determined by chain length.When m+n=20,with the decrease of m/n(18/2~14/6),PSi-EO displayed an increment in the antifoaming ability and reduction in the foam-suppressing ability,while the PSi-EO with m/n=17/3 showed an excellent antifoaming and foam-suppressing ability(antifoaming time 71.28 s,foam-suppressing time 19.34 min).With the increase of m+n and the decrease of m/n,the molecular chain of PSi-EO was extended and the amount of hydrophilic group grafting was increased,and its contact angle was also increased,and the wetting ability was reduced.The PSi-EO could form spherical micelles in aqueous solution,and the smaller aggregates could be self-assemble to form large and complex aggregates with an average particle size of 100~300 nm,and its aggregate morphology was independent of its chain length and chain link ratio.The PSi-EO molecules were more inclined to adsorb at the gas-liquid interface,and thus the surface tension of the bubble film in the vicinity of the molecules was rapidly reduced,which lead to the bubble bursting.