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Method of making a crosslinked fiber membrane from a high molecular weight, monoesterified polyimide polymer

  • US 8,328,906 B2
  • Filed: 11/28/2011
  • Issued: 12/11/2012
  • Est. Priority Date: 01/10/2008
  • Status: Expired due to Fees
First Claim
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1. A method of making a crosslinked membrane, comprising:

  • (a) preparing a polyimide polymer comprising carboxylic acid functional groups from a reaction solution comprising monomers and at least one solvent, with the preparation of the polyimide polymer taking place under dehydrating conditions such that the concentration of water in the reaction solution is maintained at between about 0 weight percent and 0.26 weight percent;

    (b) treating the polyimide polymer with a diol at esterification conditions in the presence of dehydrating conditions to form a monoesterified polyimide polymer, with the dehydrating conditions at least partially removing water produced during step (b); and

    (c) subjecting the monoesterified polyimide polymer to transesterification conditions to form a crosslinked membrane.

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