STUDIES ON THE SYNTHESIS AND PROPERTIES OF THERMOTROPIC LIQUID-CRYSTALLINE COPOLY(AMIDE-ESTER-IMIDE) DERIVED FROM N-(HYDROXYPHENYL)PHTHALIMIDE-4-CARBOXYLIC ACID WITH AMINO-ACID

Three series of copoly (amide-ester-imide)s were prepared from amino acid (4-aminobenzoic acid, 3-aminobenzoic acid, or 6-aminohexanoic acid) and N-(4-hydroxyphenyl)phthalimide-4-carboxylic acid (M1), N-(3-hydroxyphenyl)phthalimide-4-carboxylic acid (M2), or N-(2-methyl-4-hydroxyphenyl)phthalimide-4-carboxylic acid (M3) in the presence of diphenylchlorophosphate (DPCP) and pyridine as direct condensation agents. The inherent viscosities of copoly (amide-ester-imide) s were in the range of 0.13-0.95 dL/g. Thermotropic liquid crystalline (LC) behavior of these polymers was examined by differential scanning calorimetry (DSC) and optical polarizing microscopy. These copoly(amide-ester-imide)s (IIa, IIc, IIIa, and IIIc) polymerized from S-aminobenzoic acid or 6-aminohexanoic acid with M1 or M3, respectively, showed thermotropic liquid crystalline behavior in the range of 190-426 degrees C. (C) 1995 John Wiley and Sons, Inc.