Comb-shaped structure polybenzimidazole anion exchange membrane with high conductivity and preparation method thereof

A preparation method of comb-shaped polybenzimidazole anion exchange membrane with high conductivity, comprising the steps as follows:

• (1) synthesis of deprotonated comb-shaped side chain grafted polybenzimidazole material:
• dissolving polybenzimidazole in solvent A to form a solution with a mass fraction of 1-5 wt. %, and then adding acid binding agent and side chain
• without quaternary ammonium cations;
• molar ratio of the side chain
• and acid binding agent to N—H proton is both greater than 1:1;
• reacting at −18° C. to 100° C. for 48-168 h until a bright yellow liquid is formed;
• the bright yellow liquid produced by the reaction is precipitated in precipitator B to obtain a solid, which is filtered and dried in vacuum at room temperature for 12-24 h to obtain a deprotonated comb-shaped side chain grafted polybenzimidazole material;
• the side chain
• without quaternary ammonium cation, wherein R2 is halogen, aldehyde group or epoxy group;
• (2) preparation of comb-shaped structure polybenzimidazole anion exchange membrane with high conductivity:
• dissolving the deprotonated comb-shaped side chains grafted polybenzimidazole material obtained in step (1) in DMSO solvent to form a solution with a mass fraction of 1-5 wt. %, followed by adding quaternization reagent and reacting at 40° C. to 100° C. for 24-48 h, and obtaining the reaction solution;
• pouring the reaction solution into precipitator C, a solid product is precipitated, filtered and dried at room temperature for 12-24 h, the comb-shaped structure polybenzimidazole material with high conductivity is obtained, dissolving the comb-shaped structure polybenzimidazole material with high conductivity in DMSO solvent to form a casting solution with a mass fraction of 1-5 wt. %, and then casting the casting solution into a membrane, which is dried under the condition of 60° C. for 48-96 h;
• immersing the membrane in 1M KOH solution for 24-72 h, and then washing to neutral in deionized water to obtain a comb-shaped structure polybenzimidazole anion exchange membrane with high conductivity;
• the solvent A is a mixture of one or more of DMF, DMAc, NMP or DMSO;
• the precipitant B is one or more of water, ethyl acetate or acetone;
• and the precipitant C is ethyl acetate or acetone or a mixture of both;
• the specific reaction formula is as follows:
• molecular structure of the comb-shaped structure polybenzimidazole anion exchange membrane with high conductivity is as follows:
• wherein 0<x≤1;
• structure of —R1- is as follow, and the structure is the same or different:
• R3 is a carbon chain containing ether oxygen bond, with a total length of 1-14 atoms;
• R3 is the same or different;
• R4 is a hydrogen atom or halogen;
• R4 is the same or different;
• R5 is a quaternary ammonium cation, and R5 is the same or different.