NEW POLY(AMIDE-IMIDE) SYNTHESES .4. POLY(AMIDE-IMIDE)S DERIVED FROM 2,5-BIS(4-AMINOPHENYL)-3,4-DIPHENYLTHIOPHENE AND VARIOUS BIS(TRIMELLITIMIDE)S

Fifteen bis(trimellitimide)s 2a-o were prepared by condensation of the corresponding aliphatic or aromatic diamines with trimellitic anhydride. A series of structurally new poly(amide-imide)s were synthesized by the direct polycondensation of these bis(strimellitimide)s with 2,5-bis(4-aminophenyl)-3,4-diphenylthiophene using triphenyl phosphite and pyridine as condensing agents in N-methyl-2-pyrrolidone (NMP). The resultant poly(amide-imide)s have inherent viscosities in the range between 0,72 and 2,73 dL/g at 30-degrees-C in N,N-dimethylacetamide (cf. Tab. 2). The polymers are amorphous and readily soluble in polar aprotic solvents such as N,N-dimethylacetamide (DMAc) and NMP. Transparent and tough films can be cast from their solutions. Most aliphatic-aromatic poly(amide-imide)s show a glass transition in the range between 203 and 242-degrees-C in their differential scanning calorimetry (DSC) traces, whereas the wholly aromatic poly(amide-imide)s show no discernible transition before decomposition. The thermal stability of the polymers was evaluated by thermogravimetry which showed the 10% weight-loss temperatures in the range between 414 and 459-degrees-C in air and between 451 and 578-degrees-C in a nitrogen atmosphere for the aliphatic-aromatic poly(amide-imide)s and above 500-degrees-C in both air and nitrogen atmosphere for the wholly aromatic poly(amide-imide)s.