Crosslinked Hydroxyl-Conductive Copolymer/Silica Composite Membranes Based on Addition-Type Polynorbornene for Alkaline Anion Exchange Membrane Fuel Cell Applications

Crosslinked hydroxyl-conductive copolymer/silica composite membranes based on addition-type polynorbornene, poly(dodoxymethylene norbornene-co-norbornene-3-(trimethylpropyl ammonium)-functionalized silica (QP(DNB/NB-SiO2), were prepared by a sol-gel method. Copolymer composite membranes with different degree of quaternary ammonium functional silica, designated as QP(DNB/NB-SiO2-X) (X = 5, 10, 15 and 25 wt%, respectively), displayed good dimensional stabilities with low in-plane swelling rate of 1.32-3.7%, good mechanical properties with high elastic modulus of 605.4-756.8 MPa and high tensile strength of 13.2-20 Mpa. The achieved copolymer composite membranes could self-assemble into a microphase-separated morphology with randomly oriented long-range aliphatic chain/cylinder ionic channels that were imbedded in the hydrophobic PNB matrix. Among these membranes, the QP(DNB/NB-SiO2-25) showed the parameter with ionic conductivity of 9.33 x 10(-3)S cm(-1), methanol permeability of 2.89 x 10(-7)cm(2) s(-1), and ion-exchange capacity(IEC) of 1.19 x 10(-3) mol g(-1). A current density of 82.3mA cm(-2), the open circuit voltage of 0.65 V and a peek power density of 32 mW cm(-2) were obtained. (c) 2017 Society of Plastics Engineers