评价表面活性剂溶液泡沫性能的方法—真球气泡法

Method of Evaluating the Foaming Properties of Surfactant Solutions—Real Sphere Bubble Method

通过真球气泡法测定了不同价数和浓度的无机盐体系下十二烷基硫酸钠(SDS)表面活性剂溶液的表面张力和表面扩展黏度;通过Ross-Miles法测定了相应同一溶液的发泡力和泡沫稳定性;结果表明:SDS溶液的表面张力值随着各种无机盐浓度的增加而减小至不变,此时的无机盐浓度作为相对浓度100%来考察时,发现临界胶束浓度(CMC)值与添加盐的种类无关,只随无机盐的相对浓度的增加而减少;即CMC值随着无机盐的相对浓度的增加从不含无机盐时的8.3 mmol/L均收敛至最小值3.0 mmol/L;表面张力值和对应的发泡力值呈负线性关系,由此推断表面张力值可以评价发泡力;表面扩展黏度值和对应的泡沫稳定性值呈正线性关系,由此推断表面扩展黏度可以评价泡沫稳定性;无机盐种类对SDS表面活性剂发泡力和泡沫稳定性的影响力随阳离子价数(Na^(+)、Cu^(2+)、Fe^(3+))增加而增加。

The surface tension and surface expansion viscosity of sodium dodecyl sulfate(SDS)surfactantsolutions of different valences and concentrations of inorganic salt systems were measured by the true sphericalbubble method.The foaming power and foam stability of the same solution were measured by the Ross-Milesmethod.The following results are obtained:(Ⅰ)The surface tension of the SDS solution decreases with theincrease of inorganic salt concentrations until a constant value at certain concentration which is set as as arelative concentration of 100%.It is found that the critical micelle concentration(CMC)value has nothing todo with the type of added salt,but only decreases with the increase of the relative concentration of inorganicsalt,i.e.,the CMC value increases with the inorganic salt.The increase in the relative concentration of,from 8.3 mmol/L without inorganic salt,converges to the minimum value of 3.0 mmol/L;(Ⅱ)The surface tensionand the corresponding foaming force are in a negative linear relationship,and the surface tension is inferred.The foaming power can be evaluated as that,the surface expansion viscosity and the corresponding foamstability value have a positive linear relationship,from which it is inferred that the surface expansion viscositycan evaluate the foam stability;(Ⅲ)The foaming power and foam stability of SDS surfactants increases withthe valence of cations(Na,Cu,Fe).