Synthesis and characterization of thermotropic liquid crystalline poly(ester imide)s

Two closely series of poly(ester imide)s had been synthesized by solution p olycondensation of p-phenylenebis(trimellitate) dianhydride with aliphatic diamines. The differential scanning calorimetry (DSC) traces of the most po ly(ester imide)s exhibited two endotherms representing the solid state to a nisotropic phase transition (T-m1) and the anisotropic to isotropic melt tr ansition (T-m2), respectively. Observation under polarizing microscope and wide-angle X-ray diffraction (WAXD) measurements suggested that the anisotr opic phase formed above the melting paints (T-m1) had a smectic character. The thermogravimetric analyses (TGA) revealed that the thermal stabilities of the poly(ester imide)s were up to 350 degrees C. (C) 1999 John Wiley & S ons, Inc.