Synthesis and Properties of Multi-Block Copolymers Based on Polybutadiene and Aromatic Polyamides Having Unsymmetrical Structures

Abstract

Polybutadiene-aramid multi-block copolymers having structural regularity were synthesized by a one-pot two-step method of direct polycondensation using triphenyl phosphite and pyridine as condensing agents. Amine-terminated telechelic aramid oligomers were prepared by the reaction of 3,4′-oxydianiline and isophthalic acid, and condensed with α,ω-polybutadienedicar-boxylic acid giving the multi-block copolymers with inherent viscosities of 0.2—0.4 dlg−1. They were soluble in a wide range of solvents including N,N-dimethylacetamide, pyridine, and tetrahydrofuran, and gave transparent, ductile, and elastomeric films by casting from the solutions of these solvents. Depression of the glass transition temperatures of polybutadiene phase in the multi-block copolymers was observed by increasing the aramid content. The tensile strength and modulus decreased with decreasing aramid content, whereas elongation at break increased.