Synthesis and properties of soluble and light-colored poly(amide-imide-imide)s on the basis of tetraimide-dicarboxylic acid condensed from 4,4′-oxydiphthalic anhydride, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, and m-aminobenzoic acid, and various aromatic diamines

A new type of tetraimide‐dicarboxylic acid (I) was synthesized starting from the ring‐opening addition of m‐aminobenzoic acid, 4,4′‐oxydiphthalic anhydride, and 2,2‐bis[4‐(4‐aminophenoxy)phenyl]propane at a 2:2:1 molar ratio in N‐methyl‐2‐pyrrolidone (NMP), followed by cyclodehydration to the diacid I. A series of soluble and light‐colored poly(amide‐imide‐imide)s (IIIa–j) was prepared by triphenyl phosphite‐activated polycondensation from I with various aromatic diamines (IIa–j). All films cast from N,N‐dimethylacetamide (DMAc) had cutoff wavelengths shorter than 390 nm (374–390 nm) and b* values between 25.26 and 43.61; these polymers were much lighter in color than the alternating trimellitimide series. All of the polymers were readily soluble in a variety of organic solvents such as NMP, DMAc, N,N‐dimethylformamide, dimethyl sulfoxide, and even in less polar m‐cresol and pyridine. Polymers IIIa–j afforded tough, transparent, and flexible films that had tensile strengths ranging from 96 to 118 MPa, elongations at break from 9 to 11%, and initial moduli from 2.0 to 2.5 GPa. The glass‐transition temperatures of the polymers were recorded at 240–268 °C. They had 10% weight loss at a temperature above 540 °C and left more than 55% residue even at 800 °C in nitrogen. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 707–718, 2002; DOI 10.1002/pola.10153 A new type of tetraimide‐dicarboxylic acid was synthesized from m‐aminobenzoic acid, 4,4′‐oxydiphthalic anhydride, and 2,2‐bis[4‐(4‐aminophenoxy)phenyl]propane at a 2:2:1 molar ratio. A series of soluble, light‐colored poly(amide‐imide‐imide)s was prepared by triphenyl phosphite‐activated polycondensation from the diacid with various aromatic diamines. All films cast from dimethylacetamide had cutoff wavelengths shorter than 390 nm and b* values between 25.26 and 43.61, which are much lighter in color than alternating trimellitimide series. All the polymers were readily soluble in a variety of organic solvents and in less polar solvents. Polymers afforded tough, transparent, and flexible films that were characterized by good mechanical properties together with excellent thermal stability.