【摘要】 研究了一系列直链三取代和支链双取代烷基苯磺酸钠水溶液的动态表面张力(DST)和泡沫性能,考察了分子结构变化对烷基苯磺酸钠水溶液的DST和泡沫性能的影响.探讨了动态表面张力参数(t*,n,R1/2)的变化规律及其与泡沫性能的关系.结果表明,随着取代烷基链长度增加,t*和n值增大,R1/2减小,动态表面活性降低.由于双取代支链烷基苯磺酸钠分子具有特殊的柔性长支链,使得吸附膜排列紧密、膜弹性增大,因而其泡沫稳定性明显优于多取代直链烷基苯磺酸钠的稳定性.在气流法产生泡沫的过程中,动态表面张力是控制起泡高度的关键因素.更多还原

【Abstract】 Foaming properties and dynamic surface tension(DST) of aqueous solutions of a series of sodium 2,4,5-trialkyl benzene sulfonates and sodium 2,5-dialkyl benzene sulfonates were determined. The parameters of DST (t, n, R1/2) were correlated with the foaming ability of the same surfactant solution. The results indicate that the molecular diffusion in the solution, adsorption and arrangement on the air/water interface were changed with the changes of molecular structures: with the increase of the alkyl chain length, the values of t and n increase, and the value of R1/2 decreases. For 2,4,5-trialkyl benzene sulfonates, 2-alkyl and 5-alkyl have strong steric hindrance, which have a strong influence on the molecular arrangement on the air/water interface, with increasing the chain length, foam stability decreases. While the 4-alkyl chain has a weak influence on the structure of adsorption film, the 4-alkyl chain almost doesn′t influence the foam stability. For 2,5-dialkyl benzene sulfonates, the branched-alkyl chain is more flexible, which is characterized by more densely packed adsorbed molecules and higher film elasticity of the adsorption film. Therefore, the foam stability is higher than that of sodium 2,4,5-trialkyl benzene sulfonates. In the case of modified Bikerman method, DST is the key factor controlling the foaming ability.更多还原