High‐molecular‐weight poly(p‐phenyleneterephthalamide) by the direct polycondensation reaction with triphenyl phosphite

Publisher Website
Google Scholar
Abstract
Poly(p‐phenyleneterephthalamide) of high molecular weight was obtained when the polycondensation of terephthalic acid and p‐phenylenediamine was carried out in N‐methylpyrrolidone (NMP) that contained dissolved CaCl2 and LiCl in the presence of pyridine. The molecular weight of the polymer obtained varied with the amount of pyridine relative to the metal salts and with the molar ratios of CaCl2 to LiCl, the maximum ηinh value of 4.5 being obtained under the conditions Py/(CaCl2 + LiCl) ≈ 2.5 (mol/mol), CaCl2/LiCl ≈ 1.2 (mol/mol), and LiCl + CaCl2 ≈ 4 g. Among the solvents tested, NMP was significantly effective for the reaction. Polycondensations of several combinations of other dicarboxylic acids and diamines were carried out with limited success.