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AssigneesOhio Aerospace Institute, The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorsMary Ann B. Meador, Baochau N. Nguyen
Estimating the term…
Porous cross-linked polyimide-urea networks are provided. The networks comprise a subunit comprising two anhydride end-capped polyamic acid oligomers in direct connection via a urea linkage. The oligomers (a) each comprise a repeating unit of a dianhydride and a diamine and a terminal anhydride group and (b) are formulated with 2 to 15 of the repeating units. The subunit was formed by reaction of the diamine and a diisocyanate to form a diamine-urea linkage-diamine group, followed by reaction of the diamine-urea linkage-diamine group with the dianhydride and the diamine to form the subunit. The subunit has been cross-linked via a cross-linking agent, comprising three or more amine groups, at a balanced stoichiometry of the amine groups to the terminal anhydride groups. The subunit has been chemically imidized to yield the porous cross-linked polyimide-urea network. Also provided are wet gels, aerogels, and thin films comprising the networks, and methods of making the networks.
A porous cross-linked polyimide-urea network comprising a subunit comprising two anhydride end-capped polyamic acid oligomers in direct connection via a urea linkage, wherein:
A porous cross-linked polyimide-urea aerogel comprising a cross-linked and imidized subunit comprising two anhydride end-capped polyamic acid oligomers in direct connection via a urea linkage, wherein the oligomers (a) each comprise a repeating unit of a dianhydride and a diamine and a terminal anhydride group and (b) are formulated with 2 to 15 of the repeating units, and the aerogel has a density of 0.18 to 0.21 g/cm3 and a Young's modulus of 10 to 40 MPa.
Dependencies are inferred from the claim text.