Synthesis and Properties of Organosoluble Poly(amide-imide-imide)s Based on Tetraimide-Dicarboxylic Acid Condensed from 4,4’-(Hexafluoroisopropylidene)diphthalic Anhydride, 1,4-Bis(4-aminophenoxy)benzene, and Trimellitic Anhydride, and Various Aromatic Diamines

Abstract

A novel tetraimide-dicarboxylic acid (I) was synthesized starting from the ring-opening addition of 4,4’-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 1,4-bis(4-aminophenoxy)benzene (TPEQ), and trimellitic anhydride (TMA) at a 1:2:2 molar ratio in N-methyl-2-pyrrolidone (NMP), followed by azeotropic condensation to the diacid I. A series of poly(amide-imide-imide)s (PAIIs) with inherent viscosities of 1.0–1.3 dL g-1 was prepared from the diacid I with various aromatic diamines by direct polycondensation. Most of the PAIIs were readily soluble in a variety of amide polar solvents, and even in less polar m-cresol and pyridine. Solvent-cast films had a tensile strength ranging from 80 to 101 MPa, elongation at break from 10 to 17%, and initial modulus from 2.0 to 2.4 GPa, and all of them exhibited clear yield points on their stress-strain curves. The glass transition temperature of these PAIIs was recorded at 260–289°C. They had 10% weight loss at a temperature above 520°C in air or nitrogen atmosphere.