THE PREPARATION OF PERFECTLY ALTERNATING POLY(AMIDE-IMIDE)S VIA AMIDEUNIT CONTAINING NEW DIAMINE

The synthesis of N,N'-bis(4'-amino-4-biphenylene) isophthalamide (BABP I) and its applicability as a new diamine for the preparation of a ser ies of new, high T-g, perfectly alternating poly(amide-imide)s is desc ribed. BABPI was synthesized from the catalytic reduction of the corre sponding dinitro compound which was prepared by the condensation of is ophthaloyl chloride and 4-amino-4'-nitrobiphenyl. The modified selecti ve reduction technique was used for the preparation of 4-amino-4'-nitr obiphenyl from 4,4'-dinitro-biphenyl. Poly(amide-imide)s were synthesi zed by polycon densation of diamine BABPI with various commercially av ailable aromatic dianhydrides via a conventional two-step procedure. I n the first step, poly(amic-acid)s were prepared in a polar aprotic so lvent, such as N-methyl pyrrolidone (NMP) at room temperature. Dependi ng on the dianhydride used, intrinsic viscosities of poly(amic-acid)s were found to range between 0.43-0.69 dL/g. Bulk thermal imidization t echnique was used to obtain fully imidized poly(amide-imide)s at the s econd step. The synthesized poly(amide-imide)s showed good thermal sta bility up to 320 degrees C and the 10% weight loss temperatures were r ecorded in the range of 525-550 degrees C as evidenced by thermogravim etric analysis (TGA). The glass transition temperatures were found to be between 225-235 degrees C from differential scanning calorimeter (D SC) measurements. (C) 1997 John Wiley & Sons, Inc.