聚氧丙烯链对Extended表面活性剂界面性质的影响

Contribution of polypropylene oxide spacer on interfacial properties of extended surfactants

以十二醇、十四醇和十二/十四混合醇为原料,合成了三种直链烷基聚氧丙烯醚硫酸钠-3(C_nP_3S)。利用FTIR,~1H NMR进行了结构表征,分析了表面活性剂的界面和胶束溶液性质,并与十二烷基硫酸钠(SDS)和月桂基聚氧乙烯醚硫酸钠-3(SLE3S)进行了对比。~1H NMR表征结果显示,C_nP_3S的环氧丙烷平均加成数在3.0左右。实验结果表明,聚氧丙烯(PPO)链和烷基链的增长可为C_nP_3S分子提供疏水性,同时PPO链还提供极性作用,因此C_(12)P_3S和C_(14)P_3S降低表面张力的能力及乳化能力优于SDS和SLE_3S,泡沫性质略低于SDS和SLE_3S,润湿力介于SDS和SLE_3S之间,去污力等同或略优于SDS和SLE3S,同时具有优良的低温水溶性及抗钙离子性。由于同系物作用,C_(1214)P_3S混合物在泡沫、去污力和钙离子抗性等性能上表现出一定协同作用。PPO链的双亲性赋予了C_nP_3S优良性质,使其适用于个人护理及家用清洁产品。

Three kinds of extended surfactants(e-surfactants),sodium linear alkyl polyoxypropylene ether sulfates(CnP3S) were synthesized from dodecyl alcohol,tetradecyl alcohol and dodecyl/ tetradecyl mixed alcohol,respectively. Structure of the e-surfactants were characterized by FTIR and 1H NMR. Interfacial and micellar solution properties were investigated in comparison to sodium dodecyl sulfate(SDS) and sodium laureth-3 sulfate(SLE3S). The results from 1H NMR spectra indicate that the average adduct number of propylene oxide of CnP3S is about 3.0. It was found that both the polypropylene oxide(PPO) spacer and alkyl chain growth provide hydrophobicity to CnP3S molecules, at the same time,the PPO chain also provides polarity. Thus both C12P3S and C14P3S show lower surface tension,better emulsifying power,slightly worse foamability,equal or slightly better detergency in comparison to SDS and SLE3S,as well as wettability in between. They also exhibit good low-temperature solubility and calcium tolerance. C1214P3S mixture exhibits synergism on foamability, detergency and calcium tolerance due to homologues. Therefore,these excellent properties of CnP3S are brought about by the amphipathicity being contributed by the PPO spacer,which indicates that CnP3S might be candidates used in personal care and household cleaning products.