SPTES-b-PI质子交换膜的制备及表征

质子交换膜作为质子交换膜燃料电池的核心部件具有提供离子通道传递质子和隔绝两极气体的双重作用，其性能的好坏直接影响着电池性能的优劣。主链引入亲水和疏水段的嵌段芳香族共聚物，由于各嵌段之间具有热力学不相容性会产生微相分离结构，进而形成高效的质子传导通道。本文以磺化双（4-氟苯基）砜（SDFDPS）和4，4'-硫代双苯硫酚（TBBT）为单体，以间羟基苯胺为封端剂合成了带有氨端基的磺化聚芳硫醚砜（SPTES-NH₂）。嵌段聚合物SPTES-b-PI通过亲水段SPTES-NH₂与以1，4，5，8-萘四羧酸二酐（NDA）和4，4'-双（3-氨基苯氧基）二苯基砜（m-BAPS）为单体缩聚而成的疏水段聚酰亚胺（PI）的酰亚胺化偶联反应来合成，制备出了PI分子量不同的SPTES-b-PIx（x=5~20kg/mol）。SPTES-b-PIx膜显示出优异的热力学稳定性，SPTES-b-PIx膜的脱磺化反应开始于290℃高于260℃的SPTES膜，与SPTES-70相比吸水率降低。随着聚酰亚胺分子量的增大，热稳定性增加，质子传导率增加。SPTES-b-PIx的质子传导率25℃下达到0.045~0.124S/cm。

Preparation and properties of sulfonated poly(arylene thioether sulfone)-b-polyimide block copolymers as proton exchange membrane

Aromatic backbone block copolymer generally consists of hydrophilic segment and hydrophobic segment. Due to the thermodynamic incompatibility, microphase separation of block copolymers easily occurs which can form proton conductivity channel. In this paper, sulfonated poly(arylene thioether sulfone)-b-polyimide(SPTES-b-PI) copolymers were synthesized and tested for being used as proton exchange membranes(PEMs). Amine terminated sulfonated poly(arylene thioether sulfone) hydrophilic oligomers and anhydride terminated naphthalene based polyimide hydrophobic oligomers were synthesized via the step growth polymerization method. Synthesis of SPTES-b-PI was achieved by an imidization coupling reaction of hydrophilic and hydrophobic oligomers in a m-cresol/NMP mixed solvent system, and SPTES-b-PIx with different molecular weights of polyimide were obtained. As a result, the membrane prepared from the blocks of SPTES and PI showed excellent thermodynamic stability, and the desulfonation reaction of SPTES-b-PIx copolymers began around 290℃, higher than that (260℃) for SPTES. Lower water absorption than SPTES-70 was also observed. The thermal stability and the proton conductivity of SPTES-b-PIx increases with the increase of the molecular weight(5-20kg/mol) of polyimide. The proton conductivity of SPTES-b-PIx is 0.045-0.124 S/cm at 25℃.