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以巯基乙胺盐酸盐(AESH)为链转移剂、2,2’-偶氮二异丁腈为引发剂,合成了具有端氨基的聚(N-异丙基丙烯酰胺)(PNIPAAm);与甲基丙烯酰氯反应,得到可聚合的PNIPAAm大分子单体;进而与丙烯腈共聚,合成了丙烯腈-N-异丙基丙烯酰胺接枝共聚物(P(AN-g-NIPAAm)).基于浸没沉淀相转化法制备了聚丙烯腈/P(AN-g-NIPAAm)共混膜.红外及核磁分析表明,通过调控AESH的浓度可制备得到不同链长的PNIPAAm大分子单体;用激光光散射进一步测定了共聚物的重均分子量;采用鼓泡接触角及浊度测定考察了共聚物的温敏特性;XPS结果证实PNIPAAm链在膜表面发生富集;纯水压滤实验发现所制备的分离膜40℃(高于PNIPAAm的LCST)时的水通量是25℃(低于PNIPAAm的LCST)时的近2倍,具有较明显的温敏性.
Poly (N-isopropylacrylamide) (PNIPAAm) with terminal amino group was synthesized by using mercaptoethylamine hydrochloride (AESH) as chain transfer agent and 2,2’-azobisisobutyronitrile as initiator. Reacted with methacryloyl chloride to obtain polymerizable PNIPAAm macromonomer; then copolymerized with acrylonitrile to synthesize acrylonitrile-N-isopropylacrylamide graft copolymer (P (AN-g-NIPAAm)). Poly (acrylonitrile) / P (AN-g-NIPAAm) blend membranes were prepared by immersion-precipitation phase inversion method. Infrared and nuclear magnetic analysis showed that PNIPAAm macromonomers with different chain lengths were prepared by controlling the concentration of AESH. The weight average molecular weight of the copolymer was further determined by light scattering. The thermal sensitivity of the copolymer was investigated by bubble contact angle and turbidity measurement. The XPS results confirmed that the PNIPAAm chain was enriched on the membrane surface. Of the separation membrane at 40 ℃ (above LCIPAAm of PNIPAAm) when the water flux is 25 ℃ (lower than LCIPAAm LCST) almost twice, with more obvious temperature sensitivity.