Synthesis and properties of new halogen-substituted polyamides from 5-halo-m-phenylenediamines and both aliphatic and aromatic dicarboxylic acids

New halogen-substituted aromatic-aliphatic and wholly aromatic polyamides w ith high inherent viscosities were synthesized by the direct polycondensati on of 5-halo-m-phenylenediamines, where the halogens were Cl, Br, and I, wi th both aliphatic and aromatic dicarboxylic acids in N-methyl-2-pyrrolidone with a mixture of triphenyl phosphite and pyridine as a condensing agent. The solubility of the halogen-substituted polyamides was much higher than t hat of the parent polyamides derived from m-phenylenediamine. The glass-tra nsition temperatures of the substituted aromatic-aliphatic polyamides incre ased in the order Cl < Br < I, whereas the temperatures of 10% weight loss in air decreased in the reverse order. The limiting oxygen index values, as an indication of flammability, increased for the substituted aromatic-alip hatic polyamides in the order Cl < Br < I. (C) 2000 John Wiley & Sons, Inc.