Synthesis and characterization of new soluble poly(amide-imide)s derived from 2,2-bis[4-(4-trimellitimidophenoxy)phenyl]hexafluoropropane

A series of new soluble poly(amide-imide)s were prepared from the diimidedi carboxylic acid 2,2-bis[4-(4-trimellitimidophenoxy)phenyl]hexafluoropropane with various diamines by direct polycondensation in N-methyl-2-pyrrolidino ne containing CaCl2 with triphenyl phosphite and pyridine as condensing age nts. All the polymers were obtained in quantitative yields with inherent vi scosities of 0.52-0.86 dL . g(-1). The poly(amide-imide)s showed an amorpho us nature and were readily soluble in various solvents, such as N-methyl-2- pyrrolidinone, NN-dimethylacetamide (DMAc), N,N-dimethylformamide, pyridine , and cyclohexanone. Tough and flexible films were obtained through casting from DMAc solutions. These polymer films had tensile strengths of 71-107 M Pa and a tensile modulus range of 1.6-2.7 GPa. The glass-transition tempera tures of the polymers were determined by a differential scanning calorimetr y method, and they ranged from 242 to 279 degreesC. These polymers were fai rly stable up to a temperature around or above 400 degreesC, and they lost 10% of their weight from 480 to 536 degreesC and 486 to 537 degreesC in nit rogen and air, respectively. (C) 2001 John Wiley & Sons, Inc.