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US 2022/0064391 A1Published application
Method for producing pbi films without organic solvents
AssigneeUniversity of South Carolina
InventorsLAURA A. MURDOCK, LIHUI WANG, FEI HUANG, BRIAN C. BENICEWICZ
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Abstract
A novel process for making PBI films starting from gel PBI membranes polymerized and casted in the PPA process wherein acid-imbibed gel PBIs are neutralized in a series of water baths and undergo controlled drying in association with a substrate material, yielding a PBI film without the use of organic solvents.
Claims18
A process for forming a polybenzimidazole (PBI) film comprising:
- polymerizing an aromatic or heteroaromatic tetraamino compound with at least one aromatic or heteroaromatic polycarboxylic acid or ester, anhydride, or acid chloride thereof or at least one aromatic or heteroaromatic diaminocarboxylic acid in the presence of a polyphosphoric acid solvent to form a PBI polymer solution that includes the PBI polymer in solution with the polyphosphoric acid solvent;
- processing the PBI polymer solution to form a membrane precursor;
- hydrolyzing at least a portion of the polyphosphoric acid to form phosphoric acid and water, thereby causing a sol-gel transfer of the PBI polymer solution and solidification of the PBI polymer to form a PBI gel membrane;
- rinsing the PBI gel membrane and thereby removing the phosphoric acid from the gel membrane;
- drying the rinsed PBI gel membrane as it is restrained on a porous substrate and thereby forming the PBI film.
2 more elements
A dried PBI film exhibiting a tensile stress at break of at least 25 MPa.
Dependencies are inferred from the claim text.