HEMA/AA光接枝薄膜之單體競爭效應及對乙醇／水滲透蒸發分離之影響

Effect of Monomer Competition on Membrane Characteristic and Pervaporation Properties of HEMA／AA Photografted Membranes

本研究主要是以親水性單體2.2-羥基乙基丙烯酸甲酯（HEMA）與丙烯酸（AA）進行高分子光接枝聚合反應，製備超薄接枝複合膜，應用於滲透蒸發分離乙醇／水共沸混合物，研究中以不同單體組成探討單體競爭效應對接枝效率之影響，並討論單階段或多階段式光起始方式對親水性單體進行高分子光聚合接枝反應之影響，研究中光聚合親水性單體（HEMA,AA）反應後薄膜形態明顯影響其接枝膜之表面與橫切面結構，由紅外線光譜分析發現光聚合超薄膜之單體組成明顯影響其聚合接枝反應之接枝度與薄膜特性，光聚合起始方式對超薄膜之製備與特性、型態及其對滲透蒸發性能皆有顯著之影響，親水單體進行光聚合反應接枝反應化學改質可有效改善其滲透蒸發分離之性能。

The purpose of this study was to prepare hydrophilic photografted （polyacrylic acid and poly HEMA） polymer on porous support membranes. The ultra-thin photo-grafted skin layer was prepared on porous support membrane and those composited membranes were applied to separate water／ethanol mixture by pervaporation. The competition between hydrophilic monomers in photo polymerization was investigated by considering different type of vinyl monomers. The influences of the stages of photo polymerization on the degree of grafting on membranes were also discussed in this study. It was evidenced that the vinyl monomers photo-grafted onto surface of porous support significantly changed by different morphology of grafted membranes. The monomer competition on degree of grafting of photo grafted membrane and characteristic of grafted polymers were analyzed by FTIR spectra. It was found that the type of monomer and photo grafted polymerization methods played important role on the membrane properties, morphology, and separation properties. This investigation also evaluated the significantly improved in pervaporation performance by photo grafted modification on a porous support membranes.