SYNTHESIS AND CHARACTERIZATION OF NEW POLYAMIDES CONTAINING ADAMANTYLAND DIAMANTYL MOIETIES IN THE MAIN-CHAIN

This work synthesized a series of new polyamides by direct polycondens ation of 1,3-bis[4-(4-carboxyphenoxy)phenyl] adamantane (I) with vario us diamines. The diacid I was synthesized from 1,3-bis(4-hydroxyphenyl ) adamantane in two steps. Polyamides III were soluble in N-methyl-2-p yrrolidone (NMP), N,N-dimethylacetamide (DMAc), and pyridine. The poly amides had medium inherent viscosities of 0.30-0.55 dL/g and number-av erage molecular weights (M-n) of 22,000-36,000. The polyamides IIIa an d IIIb had tensile strengths of 59.8 and 77.5 MPa, elongation to break age values of 5.8 and 7.6%, and initial moduli of 1.9 and 1.8 GPa, res pectively. Their glass transition temperatures were found to be 219-29 5 degrees C by means of differential scanning calorimetry(DSC). Dynami c mechanical analysis (DMA) reveals that the incorporation of rigid an d bulky diamantane into polyamides IIIa and IIIb leads to high glass t ransition temperatures (T(g)s), at 299 and 286 degrees C, respectively . The decomposition temperatures of polyamides III at a 5% weight loss ranged from 388 to 416 degrees C in air and from 408 to 435 degrees C in N-2 atmosphere. (C) 1998 John Wiley & Sons, Inc.