Layer structures. 9. Poly(ester-imide)s with a four-layer or a six-layer repeat unit

The phase transition and transition kinetics of a liquid crystalline copoly(amide−imide) (PAI37), which was synthesized from 70 mol % pyromellitic dianhydride, 30 mol % terephthaloyl chloride, and 1,3-bis[4-(4‘-aminophenoxy)cumyl]benzene, was characterized by differential scanning calorimetry, polarized light microscopy, X-ray diffraction, and rheology. PAI37 exhibits a glass transition temperature at 182 °C followed by multiple phase transitions. The crystalline phase starts to melt at ∼220 °C and forms smectic C (SC) phase. The SC phase transforms into smectic A (SA) phase when the temperature is above 237 °C. The SC to SA transition spans a broad temperature range in which the SA phase vanishes and forms isotropic melt. The WAXD fiber pattern of PAI37 pulled from the anisotropic melt revealed an anomalous chain orientation, which was characterized by its layer normal perpendicular to the fiber direction. The transition kinetics for the mesophase and crystalline phase formation was also studied.

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Layer structures. 9. Poly(ester-imide)s with a four-layer or a six-layer repeat unit

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References 11 publications

Liquid-Crystalline Polyimides

Liquid-Crystalline Polyimides

Phase Transition and Transition Kinetics of a Thermotropic Poly(amide−imide) Derived from 70 Pyromellitic Dianhydride, 30 Terephthaloyl Chloride, and 1,3-Bis[4-(4‘-aminophenoxy)cumyl]benzene

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