【摘要】 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.更多还原

【Abstract】 PNIPAAm with terminal amino groups was synthesized using 2-aminoethanethiol hydrochloride(AESH) as a chain transfer agent.It was then reacted with methacryloyl chloride to result in macromer,vinly PNIPAAm.A graft copolymer,P(AN-g-NIPAAm) was synthesized through the copolymerization of acrylonitrile(AN) and vinyl PNIPAAm.Using this graft copolymer as an additive,thermal responsive PAN-based membranes were prepared by the immersion precipitation phase inversion method(IPPI).Results from FTIR and NMR indicate that the molecular weight of PNIPAAm can be effectively modulated by changing the concentration of AESH.Then,the weight average molecular weight(Mw) was measured by laser scattering.Results of captive bubble contact angle measurements and turbidity analysis show that the graft copolymers are still thermally responsive,which is more remarkable with higher PNIPAAm content.XPS analysis proves that the PNIPAAm graft chains are enriched at the membrane surface and pore surface during the course of IPPI because of the hydrophilicity of PNIPAAm.Pure water flux at 40℃(above the LCST of PNIPAAm) is almost twice as that at 25℃(below the LCST of PNIPAAm),which is due to the conformation change of PNIPAAm chains.All these results demonstrate the synthesized graft copolymers are effective additives for the preparation of thermal responsive PAN membranes.更多还原