Crosslinked anion exchange membranes prepared from highly reactive polyethylene and polypropylene intermediates

Abstract

To obtained polyolefin-based anion exchange membranes (AEMs) with high performance in high efficiency, reactive polyolefin intermediates were prepared via polymerization of ethylene or propylene with 1-iodo-10-undecene (IUD) by single-site rac-ethylenebis(indenyl)Zr(IV) dichloride and dimethyl (pyridylamido)Hf(IV) catalysts, respectively. The catalytic activity for synthesis of these reactive polyolefin intermediates was up to 2.94 × 106 for ethylene copolymers (PEI-x) and 7.20 × 106 gpolymer molcat.−1 h−1 for propylene copolymers (PPI-x), respectively. Moreover, incorporation ratio of IUD in copolymers was high up to 19.8 (PEI-x) and 29.7 mol% (PPI-x), respectively. These copolymers could be well dissolved in o-xylene, make them easily crosslinked and quaternized to give polyolefin-based AEMs. These AEMs with crosslinking structure exhibited high hydroxide conductivity (131 and 143 mS/cm for PEI-20-C100-QA and PPI-30-C70-QA at 80 °C, respectively) and excellent alkaline stability without visible loss in hydroxide conductivity after 1680 h. These AEMs exhibited evident microphase separation via microphase study, presented low swelling ratio even with high water uptake. A H2/O2 fuel cell with PEI-20-C100-QA presented a peak power density of 439 mW cm−2 without optimized membrane electrode assembly fabrication process.