US 11,777,124 B2
Proton-conducting PBI membrane processing with enhanced performance and durability
Laura A. Murdock, Columbia, SC (US); Fei Huang, West Columbia, SC (US); and Brian C. Benicewicz, Columbia, SC (US)
Assigned to University of South Carolina, Columbia, SC (US)
Filed by University of South Carolina, Columbia, SC (US)
Filed on Mar. 8, 2021, as Appl. No. 17/194,417.
Claims priority of provisional application 62/985,977, filed on Mar. 6, 2020.
Prior Publication US 2021/0280883 A1, Sep. 9, 2021
Int. Cl. H01M 8/103 (2016.01); H01M 8/1004 (2016.01); C25B 13/08 (2006.01); C08J 5/18 (2006.01); C08K 3/32 (2006.01); H01M 8/10 (2016.01)
CPC H01M 8/103 (2013.01) [C08J 5/18 (2013.01); C08K 3/32 (2013.01); C25B 13/08 (2013.01); H01M 8/1004 (2013.01); C08J 2379/04 (2013.01); C08K 2003/329 (2013.01); H01M 2008/1095 (2013.01); H01M 2300/0082 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A process for making a polybenzimidazole film comprising:
forming a polymerization composition comprising a polyphosphoric acid, an aromatic or heteroaromatic tetraamino compound, and an aromatic or heteroaromatic polycarboxylic acid compound, wherein the aromatic or heteroaromatic carboxylic acid compound comprises an aromatic or heteroaromatic polycarboxylic acid or ester, anhydride, or acid chloride thereof and/or comprises an aromatic or heteroaromatic diaminocarboxylic acid;
polymerizing the aromatic or heteroaromatic tetraamino compound with the aromatic or heteroaromatic carboxylic acid compound to form a polymer solution comprising a pol benzimidazole dissolved in the polyphosphoric acid;
shaping the polymer solution to form a membrane precursor comprising the polymer solution;
hydrolyzing at least a portion of the polyphosphoric acid to form phosphoric acid and water, upon which the membrane precursor forms a gel membrane comprising the polybenzimidazole, the gel membrane being a self-supporting membrane capable of incorporating a liquid content of about 60 wt. % or more without loss of structure;
rinsing the gel membrane;
restraining the gel membrane in an X-Y plane direction;
drying the rinsed gel membrane as it is restrained to form a dried film; and
immersing the dried film into an inorganic or organic acid bath.