| 摘要 |
The present invention is directed to polyimide systems which simultaneously offer low toxicity, a high glass transition temperature, excellent thermal oxidative stability, and desirable processing characteristics. These various polyimide systems include mixtures of monomeric reactants, polyimide-precursor reaction products, polyimides, and polyimide-containing articles. In one aspect of the invention, the mixture of monomeric reactants includes at least one dianhydride or a derivative thereof, and at least one diamine. The diamine may be 4,4'-[1,4-phenylene-bis(1-methylethylidene)]bisaniline, 4,4'- [1,3-phenylene-bis(1-methylethylidene)]bisaniline, and/or a derivative thereof. The diamine also may include a phenylenediamine, 2,2- bis[4-(4-aminophenoxyl)phenyl]propane, 4,4' (1,4-pheny-lene-bismethylene)bisaniline, and/or a derivative thereof. In addition, the mixture may include a reactive end-capping agent and/or a non-reactive end-capping agent. Also, if desired, the mixture of monomeric reactants may be a dry mix or a solution. The invention also is directed to articles formed from mixtures of monomeric reactants, articles formed from polyimide-precursor reaction products, and articles formed from polyimides themselves. Non-limiting examples include a powder, a neat resin, a coating, a film, a membrane, a foam, an adhesive, a fiber, a composite, a laminate, a prepreg, a part, and bushing.
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