BPO和AIBN作引发剂对阳离子交换膜性能的影响

Effect of BPO and AIBN as initiators on the performance of cation exchange membrane

摘要:

改进传统制备聚偏氟乙烯(PVDF)均相阳离子交换膜的方法，利用引发剂和浓硫酸磺化直接制备PVDF均相阳离子交换膜。通过溶剂蒸发法制备了含引发剂过氧化苯甲酰(BPO)和/或偶氮二异丁腈(AIBN)的PVDF阳离子交换膜，研究不同引发剂及其含量对膜结构和膜性能的影响。利用热场发射扫描电镜(FE-SEM)和傅立叶红外光谱(FTIR)分析膜的形貌结构，结果表明含有BPO的阳离子交换膜中PVDF与苯乙烯形成了半互穿网络结构，而含有AIBN的阳离子交换膜中苯乙烯接枝在线性PVDF链上并形成相分离结构。PVDF阳离子交换膜的结构和性能受AIBN和BPO含量的影响。当AIBN含量为0.25 g，BPO含量为0.1g时离子交换膜的膜电阻达到最低为4.2Ω∙cm^2 ，离子交换容量最高为1.6 meq/g；当AIBN含量为0.15g，BPO含量为0.1g时离子交换膜的迁移数为95.15%。最后通过循环伏安法和计时电位法进一步验证了引发剂对膜电阻和迁移数影响的实验结论。

Abstract:

A conventional method for preparing a polyvinylidene fluoride (PVDF) homogeneous cation exchange membrane is improved. The PVDF homogeneous cation exchange membrane was directly prepared by using initiators and sulfonation with concentrated sulfuric acid. A series of PVDF cation exchange membranes using the initiator benzoyl peroxide (BPO) and/or 2,2'-azobis(2-methylpropionitrile) (AIBN) were prepared by solvent evaporation. The effects of different initiators and their contents on the membrane structure and membrane properties were investigated. The physical morphology and chemical structure of PVDF cation exchange membranes were analyzed by thermal field emission scanning electron microscopy (FE-SEM) and Fourier Transform infrared spectroscopy (FTIR). The results show that PVDF and styrene form a semi-interpenetrating network structure in the cation exchange membrane containing BPO. In the cation exchange membrane containing AIBN, styrene is grafted on the linear PVDF chain and forms a phase separation structure. The structure and properties of the PVDF cation exchange membrane are affected by the content of AIBN and BPO. When the AIBN content is 0.25 g and the BPO content is 0.1 g, the membrane resistance of the ion exchange membrane reaches a minimum of 4.2 Ω∙cm^2. The ion exchange capacity is up to 1.6 meq/g; when the AIBN content is 0.15 g and the BPO content is 0.1 g, the migration number of the ion exchange membrane is 95.15%. The effects of different initiators and their contents on membrane resistance and migration number were further verified by cyclic voltammetry and chronopotentiometry.