SYNTHESIS OF SEQUENTIAL POLYAMIDE BY DIRECT POLYCONDENSATION

A convenient method for the synthesis of sequential polyamide (head-to-head, or tail-to-tail) has been developed. This polymer was prepared by the direct polycondensation of symmetric monomer (YccY), isophthalic acid (2b) with nonsymmetric monomer (XabX), 2,6-dimethyl-p-phenylenediamine (4) using the activating agent, diphenyl(2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphate (1). The polycondensation was carried out by slow addition of 2b to 4, and gave the sequential (head-to-head, or tail-to-tail) polyamide (14) with inherent viscosity of 0.2 dlg-1. The authentic polyamides with different values of s (probability of -accb- placement) were prepared to verify the structure of polyamide 14. Furthermore, the model reaction was studied in detail to demonstrate the feasibility of the sequential polyamidation.