Cho, Hyeongrae Hur, Eun Henkensmeier, Dirk Jeong, Gisu Cho, Eunae Kim, Hyoung Juhn Jang, Jong Hyun Lee, Kwan Young Hjuler, Hans Aage Li, Qingfeng Jensen, Jens Oluf Cleemann, Lars Nielausen 2024-01-20T09:02:50Z 2024-01-20T09:02:50Z 2021-09-02 2014-09 0014-3057 https://pubs.kist.re.kr/handle/201004/126432 Methylation of polybenzimidazole leads to positively charged polymer backbones, and moveable anions. Ion exchange of methylated PBI-OO in phosphoric acid (PA) shows that the resulting polymers dissolve. meta-PBI, however, absorbs about 400 wt% PA while remaining a self supported membrane. We investigate the properties of blend membranes, employing meta-PBI for mechanical integrity and methylated PBI-OO for high PA uptake and resulting proton conductivity. While small additions of PBI-OO decrease the tensile strength of blend membranes (58 MPa for 10% PBI-OO), further addition leads to an increase, and 50% blend membranes show again a tensile strength of 74 MPa, just 3 MPa lower than pure meta-PBI membranes. Thermal stability of iodide exchanged blend membranes appears to be remarkably high, probably because cleaved iodomethane does not evaporate but methylates meta-PBI. PA concentration in doped membranes of 60-63% is reached by doping in 60% PA (blend; 6.3 PA/repeat unit) and 70% PA (meta-PBI; 4.6 PA/r.u.). This suggests that blends absorb PA more strongly. Both membranes show similar conductivity between rt and 140 degrees C, indicating that PA concentration describes these membranes better than PA/r.u. In the fuel cell, blend membranes show similar or better performance than meta-PBI. In the TGA, blends doped in 20% PA showed a stable plateau between 115 and 180 degrees C, while meta-PBI lost weight continuously. (C) 2014 Elsevier Ltd. All rights reserved. English Pergamon Press Ltd. meta-PBI/methylated PBI-OO blend membranes for acid doped HT PEMFC Article 10.1016/j.eurpolymj.2014.06.019 1 European Polymer Journal, v.58, pp.135 - 143 European Polymer Journal 58 135 143 N scie scopus 000341675400014 2-s2.0-84904668390 Polymer Science Polymer Science Article CONTAINING POLYBENZIMIDAZOLE PBI FUEL-CELLS POLYMER ELECTROLYTE THERMAL-STABILITY EXCHANGE MEMBRANE Methylated PBI-OO Polybenzimidazolium Phosphoric acid doping High temperature polymer electrolyte fuel cell Polybenzimidazole Blend membranes