Semi-aromatic Polyamides and Polyhydrazides Based on Bisacid A2

The attempted preparation of linear polyamides and polyhydrazides based on 2,2'-bis (4 phenyleneoxy) propane-0,0'-diacetic acid (hereinafter referred to as Bisacid A2) by a number of synthetic routes is reported. It was found that polymers having molecular weights high enough to render them film forming were obtained only when the low temperature Schotten-Bauman solution polycondensation technique was employed. This method involves the reaction of the diacid chloride of Bisacid A2 (known as Bischloride A2) with aromatic and semi-aromatic diamines in an amide solvent. It was observed that maximum molecular weights were obtained when a reactant ratio other than the theoretical 1:1 stoichiometry was used. In order to explain this phenomenon an investigation of the monomer, Bischloride A2, and of the polyamides formed from it was undertaken. It was found that the Bischloride A2 contained a number of impurities, the most significant of which was thee -chloro derivative. It was also found. that the. polymers were highly branched. The implied degree of branching was greater than could be accounted for by the « -chloro derivative and it was therefore proposed that the | electrophilicity of the acid chloride and the basicity of the solvent combine to promote the formation of imide branch points on the polymer chain. This makes a significant contribution to the understanding of the low temperature Schotten-Bauman solution polycondensation as it is applied to aliphatic acid chlorides. A number of polyamides and polyhydrazides based on Bisacid A2 were prepared. Their physical and chemical properties were investigated and compared with those of similar commercially produced polymers.