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以八官能度倍半硅氧烷(BCP-POSS)为引发剂,用两步原子转移自由基聚合(ATRP)合成了以聚甲基丙烯酸甲酯-b-聚苯乙烯为臂的星型POSS-(PMMA-b-PS)8嵌段共聚物。用后磺化方法制备具有相同磺化度的磺化杂化高分子POSS-(PMMA-b-SPS)8,并用以制备了质子交换膜(PEM)。分析了在不同水合状态下两种PEM的传导率随着湿度的变化规律,发现在同样低水合状态下具有较长SPS链段的PEM其质子传导率较高;TGA分析结果表明,两种PEM都具有高温保水性能和高的初始热分解温度;用透射电子显微(TEM)和原子力显微镜(AFM)分析了不同嵌段比例PEM的微相结构,发现具有较长SPS链段的PEM有利于质子传导的两相连通的微相形貌;用低场核磁共振分析仪测定了自旋-自旋弛豫时间T2和不同共聚物低水合状态下链段分子运动特性,发现具有较长SPS链段的PEM有较狭长且连通性较好的微相分离形貌,显示出较高的质子自旋扩散系数,在低湿度环境下具有较高的质子传导率。
The star POSS with poly (methyl methacrylate) -b-polystyrene as the arms was synthesized by two-step atom transfer radical polymerization (ATRP) using octa-functional silsesquioxane as initiator - (PMMA-b-PS) 8 block copolymer. The sulfonated hybrid polymer POSS- (PMMA-b-SPS) 8 with the same degree of sulfonation was prepared by post-sulfonation method and used to prepare proton exchange membrane (PEM). The conductivity of two PEMs under different hydration conditions was analyzed with the change of humidity. It was found that the proton conductivity of PEM with longer SPS segment in the same low hydration state was higher. The results of TGA analysis showed that the two PEMs Both had high temperature water retention capacity and high initial thermal decomposition temperature. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) were used to analyze the microphase structures of PEM with different block ratios. It was found that PEM with longer SPS segment was beneficial Proton conduction of the two phase micro-phase morphology; low-field nuclear magnetic resonance analyzer measured spin-spin relaxation time T2 and different copolymer low hydration state segment molecular motion characteristics and found to have a longer SPS chain The PEM has a narrow and well-spaced microphase separation morphology with high proton spin diffusion coefficient and high proton conductivity in low humidity environment.