反相微乳液聚合制备聚丙烯酰胺水凝胶微球研究

以油酸/Span20/OP10为复合乳化剂,柴油为连续相,采用反相微乳液聚合制备了聚丙烯酰胺水凝胶微球.通过微乳面积等值图、拟三元图确定出体系中乳化剂最佳比例为w(油酸)∶w(Span)∶w(OP10)=41∶31∶28;在最佳聚合点处,油相、乳化剂相、水相分别占体系质量的34.62%,15.38%,50.00%.应用冷冻蚀刻透射电子显微镜、扫描电子显微镜及动态光散射分别对聚合前后的微乳液体系进行表征,可以看出聚合前微乳液中存在大量反胶束(团)(10nm以下)及溶胀胶团(约50nm)结构,聚合后得纳米级水凝胶微球,前后尺寸相差不大.同时测定油酸/Span20/OP10复合乳化剂水溶液与桩西原油之间的界面张力并与反相微乳聚合常规乳化剂的结果进行对比,发现前者界面张力较低,能够起到驱油用表面活性剂的作用.

Preparation of the nanometer-level acrylamide hydrogel microspheres by inverse microemulsion polymerization

Using oleic acid/Span20/OP10 as compound emulsifier and diesel oil as continuous phase,acrylamide hydrogel microspheres is synthesized by inverse microemulsion polymerization.The optimal ratio of the compound emulsifier is determined according to area contour diagram and pseudoternary phase diagram,and the mass ratio of oleic acid to Span20 to OP10 is 41∶31∶28.At the optimal polymerization point,the mass fractions of oil phase,emulsifier phase and water phase are 34.62%,15.38% and 50.00% separately.The microemulsions before and after the polymerization are characterized respectively by freeze-etching transmission electron microscope,scanning electron microscope and dynamic light scattering,it is shown that there is a great deal of reverse micelle structure (below 10 nm) and swelling micelle (above 50 nm) in the microemulsion before polymerization,the microemulsion after polymerization is nanometer-level hydrogel microspheres,and there is a little difference between the sizes of the particles of the microemulsions before and after polymerization.The interfacial tension between the oleic acid/Span20/OP10 compound emulsifier solution and ZhuangXi crude oil is measured and is compared with that between several conventional emulsifier solutions obtained by inverse microemulsion polymerization and ZhuangXi crude oil,it is found that the interfacial tension of the former is lower,and so it can be used as oil displacement surfactant.