SYNTHESIS AND CHARACTERIZATION OF TOUGH POLYAMIDES DERIVED FROM 4,9-BIS[4-(4-AMINOPHENOXY)PHENYL]DIAMANTANE

A series of new polyamides was synthesized by direct polycondensation of the 4,9-bis[4-(4-aminophenoxy)-phenyl]diamantane (I) with various d icarboxylic acids. The polyamides had high inherent viscosities and nu mber-average molecular weights ((M) over bar(n)) of 0.65-1.65 dl g(-1) and 32000-140000, respectively. Although the symmetrical and rigid 4, 9-diphenyldiamantane units were incorporated into polyamide III, espec ially, most polyamides III were extremely tough. Their elongation valu e at break was up to 60.5%. These films had tensile strength up to 116 .1 MPa, and initial modulus reached 2.1 GPa. Two relaxations occurred on the temperature scale between 0 and 400 degrees C in these polyamid es. Their oc relaxations arose at high temperatures, ranging from 342 to 381 degrees C. Moreover, these polyamides remained quite stable at high temperatures and maintained good mechanical properties (G'approxi mate to ca. 10(8) Pa) up to temperatures close to the main transition markedly exceeding 330 degrees C. Furthermore, incorporating bulky dia mantane units and the flexible ether linkages into the polyamides III, contributes toward the good solubility of most polyamides. In additio n: their temperatures at a 5% weight loss ranged from 384 to 433 degre es C in air and from 387 to 436 degrees C in N-2 atmosphere. (C) 1998 Elsevier Science Ltd. All rights reserved.