以油酸为油相的空白O/W微乳体系研究

Oil-in-water Microemulsion with Oleic Acid as the Oil Phase

关键词:  油酸  微乳  相行为  电导率

Key words:  oleic acid  microemulsion  phase behavior  conductivity

摘要:

目的 研究以油酸为油相的不同组成微乳体系的相行为特点，考察常见乳化剂和助乳化剂增溶特性，获得水增溶及油酸增溶量均较大的O/W微乳体系。方法 采用伪三元相图法，以微乳区域面积（A_T）、最大增溶水量（W_m）及对应的乳化剂用量（S_m）为水增溶参数，O/W结构能容纳的最大油酸量（O_m）为油酸增溶参数，通过比较筛选出最适乳化剂、助乳化剂及两者质量比，并通过体系电导率随含水量变化及相转变点绘出O/W微乳区域。结果 多元醇为助乳化剂时水增溶量有限且易形成凝胶；吐温类乳化剂中吐温20水增溶量最大，吐温80油酸增溶量最大，其油水增溶量与HLB值并不完全成正比；选用吐温80/无水乙醇为混合乳化剂，随着吐温80比例下降，最大油酸增溶量逐步下降，水增溶量先上升再下降，两者比例在1∶1时，所绘制三元相图的微乳区域面积最大，但形成的O/W微乳区域亦有限。结论 以油酸为油相，可采用质量比1∶1的吐温80/无水乙醇为混合乳化剂，其水增溶和油酸增溶量均较大，可形成一定区域的O/W微乳。

Abstract:

OBJECTIVE To investigate the phase behavior of microemulsion, frequently-used emulsifier and co-emulsifier's solubilization ability with oleic acid as the oil phase and find the best quaternary system for water solubilization and oleic acid solubilization. METHODS Pseudo-ternary phase diagrams were constructed to screen the emulsifier, co-emulsifier and mass ratio for both by water solubilization parameters (A_T, W_m, S_m) and oleic acid solubilization parameter (O_m). O/W microemulsion area in phase diagram was determined by conductivity and phase inversion point.RESULTS The pseudo-ternary system was apt to form gels and the amount of water solubilization was limited with polyalcohol as co-emulsifier. Tween 20 had the maximum amount of water solubilization, but tween 80 had the best O_m; the amount of oil/water solubilization was partly related to the HLB value. When using tween 80/absolute alcohol as mix-emulsifier, O_m was in direct to their mass ratio, but water solubilization was not completely; the biggest A_T was in 1∶1 mass ratio, but the O/W microemulsion area was limited. CONCLUSION The quarternary system of olelic acid, water and tween 80/ethanol with a mass ratio equal to 1∶1, has a clear O/W structure and proper amount in water and oleic acid solubilization.