研究并讨论了内水相镁盐与疏水乳化剂 PGPR 对油包水(W/O)乳液稳定性的影响。制备 W/O 乳液的油水质量比为 6:4,油相中疏水乳化剂聚甘油蓖麻醇酸酯(PGPR)质量分数为为 0.5%-2.0%, 水相中六水氯化镁的质量分数为 0%-12.0%. 采用 Turbiscan LabExpert 稳定性分析分析 W/O 乳液在贮藏 14d 过程中的整体稳定性。结果表明:在 14d 的贮藏过程中,液滴的聚沉和沉淀会导致乳液失稳。提高疏水乳化剂 PGPR 和镁盐的浓度可提高W/O 乳液的稳定性。对 W/O 乳液的粒径分布及油水两相界面特性进行分析,发现 W/O 乳液稳定的机制在于乳液粒径的减小以及油水界面张力的降低。此外,油水两相界面粘弹性也在一定程度上改善了乳液稳定性,油水界面膜强度值随着镁盐含量的增加呈现先上升后下降的趋势。
The effect of PGPR and added magnesium chloride hexahydrate on properties of W/O ( water- in-oil) emulsions was investigated. W/O emulsions were formulated with 60% oil phase containing 0.5%, 1.0% and 2.0% PGPR and 40% aqueous phase containing magnesium salt at various concentrations from 0 to 12. 0%. Stability of these W/O emulsions was studied with Turbiscan Lab Expert during 14-day storage. The result indicated that coalescence and sedimentation were the main reasons for destabilization. By increasing the concentrations of PGPR and magnesium chloride, TSI values of W/O emulsions decreased and therefore W/O emulsions became more stable with respect to coalescence. The stabilization mechanism was attributed to the decrease of emulsion droplets and the reduction in interfacial tension. Besides, interfacial viscoelastic measurements between soybean oil and water were conducted. The results indicated that stabilizing effect of PGPR and magnesium salt was not due to the rheological properties of interracial film. The viscoelastic parameters of interracial film increased at a lower concentration of magnesium salt (below 2% ) while further increasing the concentration of magnesium salt to 6% led to a slight decrease of interfacial viscoelastic parameters. Increasing the concentration of PGPR from 0. 5% to 2% led to a reduction in viscoelastic parameters.