Preparation and characterization of wholly aromatic para-linked copolyamides of poly(p-phenyleneterephthalamide)

Abstract

Wholly aromatic para-linked copolyamides of poly(p-phenyleneterephthalamide) have been prepared by direct polycondensation via a phosphorylation reaction using various amounts of p-aminobenzoic acid, toluene-p-diamine or nitroterephthalic acid (NTA) as comonomer. Viscosity number, perhaps degree of polymerization as well, increased with increasing comonomer content, whereas crystallinity of copolymers decreased. In particular, a bulky nitro group decreased crystallinity and the copolymers with NTA content > 50 mol% were amorphous and similar to poly (p-pheneylenenitroterephthalamide). Melting point was not greatly changed by copolymerization. Thermal decomposition temperatures of copolymers containing NTA were lower than those of other copolymers by ca. 100 °C.