Summary: Styrene‐maleic imide copolymer with benzimidazole side group was prepared from 2‐amino‐benzimidazole and styrene‐maleic anhydride copolymer. The structures of the new styrene‐maleic imide copolymers from both random and alternating styrene‐maleic anhydride copolymer were characterized by FTIR, DSC, and gel permeation chromatography (GPC). Styrene‐maleic imide copolymer has good solubility, excellent film forming ability, and is easy to prepare, though the solubility of styrene‐maleic imide copolymer decreases a little with increasing maleic imide. The proton conductivity of phosphoric acid doped styrene‐maleic imide copolymer was studied. The temperature dependence of proton conductivity in H3PO4 doped a‐styrene‐maleic imide copolymer can be fitted by a simple Arrhenius equation very well, while H3PO4 doped r‐styrene‐maleic imide copolymer has somewhat deviation from Arrhenius equation. The structure of alternating copolymer is more favorable for proton transport contributed by hopping mechanism. The proton conductivity of phosphoric acid doped styrene‐maleic imide copolymer can be improved by increasing the acid doping level or the imidazole content.
