CONTROL OF STRUCTURAL ISOMERISM IN POLYAMIDES.

Abstract

When a bifunctional monomer of the type X-ab-X, in which the two equal functions X B(being bound to different parts of the molecule) must have different reactivities, is polycondensed with a monomer of the type Y-cc-Y- structural isomerism must exist in the resulting macromolecules. This phenomenon, which is analogous to the structural isomerism arising from head-to-tail and head-to-head/tail-to-tail enchainments in vinyl polymers, has been very little investigated. In the present paper the authors report the isomeric composition, determined by chemical methods, of polyamides obtained from (Xa) or (Xb) and from ethylene diamine by different polycondensation methods. In experiments, first the monomers were synthesized and then polymerized by polycondensation methods. Experimental data and tabulated and evaluated. It is concluded that not only can the investigation of structural isomerism in condensation polymers lead to the synthesis of new polymers with unusual properties, but it also can be used as a useful tool to investigate (1) the conditions under which trans-esterification or trans-amidation reactions take place in polyesters or polyamides, respectively, and (2) some mechanistic aspects of interfacial polycondensation.