| 摘要 |
An improved synthesis for PMR-type polyimides, including first preparing a dimer of 5-norbornene-2,3-dicarboxylic acid, or acid ester or anhydride and 4,4'-methylenedianiline. This dimer is then reacted with the dimethyl ester of 3,3',4,4'-benzophenonetetracarboxylic acid and 4,4'-methylenedianiline. The resulting polyimide prepolymer exhibits superior physical properties and is substantially free of the undesired trimer of 5-norbornene-2,3-dicarboxylic acid, or acid ester or anhydride and 4,4'-methylenedianiline.
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