单一及复合表面活性剂对联苯菊酯微乳液的影响

Effects of Pure and Mixed Surfactants on Bifenthrin Microemulsion

通过对单一及复合型表面活性剂水溶液临界胶束浓度(CMC)和表面张力(γcmc)的测定分析,研究了表面活性剂对以水为介质、环己酮为溶剂形成的联苯菊酯质量分数为2.5%微乳液相行为及稳定性的影响。结果表明,在几种单一非离子表面活性剂中,苯乙烯基苯酚聚氧乙烯聚氧丙烯醚嵌段型非离子表面活性剂EPE的γcmc最低,为28.18mN/m;按m(EPE)∶m(SDBS)=2∶1形成的复合型表面活性剂水溶液的γcmc更低,为27.60mN/m,有利于O/W型微乳液的形成,当其质量分数为10%时,配制联苯菊酯质量分数为2.5%微乳液的有效成分热贮分解率为2.35%。

The critical micelle concentration （CMC） and surface tension of several different types of surfactants and their mixtures were measured in the system with water as continuous medium and cyclohexanone as solvent. Their effects on phase behavior and physical stability of 2.5 % bifenthrin microemulsion were investigated in detail. Among several pure surfactants, the CMC of triphenylphenoxy polyoxyethylenyl polyoxypropylene（ EPE type） with block nonion surfactant stucture is the lowest, γcmc = 28. 18 mN/m. The CMC of a mixture of EPE and SDBS [m（EPE）：m（SDBS） =2：1] is 27.60 mN/m, which is further lower than that of pure EPE. This is very helpful to form O/W type microemulsion. When the dosage of the mixture was about 10% , the heat storage decomposition rate of 2.5% bifenthrin microemulsion was 2.35%.