| 摘要 |
An N-substituted polyamide-imide essentially composed of identical or different repeating units of the formula I <IMAGE> (I) where R1 is one of the following tetravalent aromatic radicals <IMAGE> <IMAGE> <IMAGE> <IMAGE> <IMAGE> and X is a bond or one of the following linkers <IMAGE> C(CF3)2, Si(CH3)2; where R2 and R4 are each, independently of one another, one of the following divalent aromatic radicals <IMAGE> <IMAGE> <IMAGE> <IMAGE> and where X has the abovementioned meanings and where R3 is hydrogen or a monovalent radical such as C1-C6-alkyl or phenyl, and the C1-C6-alkyl-, C1-C6-alkoxy-, aryl- or halogen-substituted derivatives thereof, and precursors (monomers) therefor, are described.
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