Synthesis and characterization of new aromatic poly(amide–imide)s derived from 1,4-bis(4-aminophenoxy)-2-t-butylbenzene and various bis(trimellitimide)s

A series of novel t-butyl group-containing poly(amide–imide)s IIIa–m were synthesized by the direct polycondensations of 1,4-bis(4-aminophenoxy)-2-t-butylbenzene (BAP-tBB) with various aromatic bis(trimellitimide)s IIa–m in N-methyl-2-pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. Poly(amide–imide)s III having inherent viscosities between 0.67 and 1.77 dl g−1 were obtained in quantitative yields. Most of the resulting polymers were readily soluble in polar solvents such as NMP and N,N-dimethylacetamide. All of the soluble poly(amide–imide)s afforded transparent, flexible, and tough films. The glass transition temperatures of these polymers were in the range of 243–300°C, and the 10% weight loss temperatures were above 490°C in nitrogen. The properties of poly(amide–imide)s III were compared with those of the corresponding poly(amide–imide)s III′ prepared from the bis(trimellitimide) of BAP-tBB and various aromatic diamines.