ABSTRACT A variety of concepts for structural modification such as flexible bridging linkages, bulky substituents, noncoplanar conformation unit, and bulky pendent group have been used to enhance the solubility and processability of polyamides, polyimides and polyamide-imides which were derived from several new diamines, dicarboxylic acids and diimide-dicarboxylic acids. It was observed that the incorporation of flexible units, such as aryl ether, hexafluoroisopropylidene, sulfonyl, isopropylidene, oxyethylene and hydroxyl units, and bulky substituents such as tert-butyl group, and noncoplanar conformation such as 2,2`-dimethyl-4,4`-biphenyl unit, as well as of pendent groups such as cyclododecylidene, adamantane, tricyclodecane and diphenylmethylene, enhances the solubility and processability of these polymers. In comparison with the effect of various structural modifications on the polymer properties, the incorporation of rigid and bulky pendent group such as adamantane group led to the most success. The introduction of sulfonyl and oxyethylene units in the polymer backbone showed relatively less satisfied results.
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