Synthesis and properties of aromatic polyamides and polyamide–smectic oligomer graft copolymer

Abstract

Two series of polyamides 1 and 2, composed of succinic acid and aromatic diamines, were synthesized in the absence and in the presence of p-aminobenzoic acid (ABA) by a direct polycondensation using a phosphorylation polyamidation. Diamines used were 1, 3-phenylenediamine, 1, 4-phenylenediamine, 4-aminodiphenyl ether, 4, 4′-diaminodiphenyl sulfide, and 4-aminodiphenyl sulfone. Polyamides 1 and 2 have 0.10—0.54 dl g−1 and 0.38—0.76 dl g−1 of [η] and 2.1—23.6% and 8.2—23.5% of crystallinity, respectively. Polyamide 2-smectic oligomer graft copolyamide, polyamide 3c, was also prepared from the polycondensation of dicarboxyl terminated smectic macromonomer (MacMHB) and 4-aminodiphenyl ether in the presence of ABA. Polyamide 3c exhibits a mesophase over the temperature range from 98.1 to 122.2°C, whereas polyamides 1 and 2 exhibit no melting process. The thermal degradation of polyamides 1 and 2 began at temperature range of 272—345°C and 356—417°C, respectively. On the other hand, polyamide 3c degrades at 332°C through a two-step one. © 1994, The Society of Polymer Science, Japan. All rights reserved.