POLY (p-PHENYLENE TEREPHTHALAMIDE) FIBER FROM THE PARTIALLY N-CYANOETHYLATED HOMOLOGUE BY REMOVAL OF THE SUBSTITUENT WITH HEAT TREATMENT

Abstract

p-Phenylenediamine, N, N′-dicyanoethyl-p-phenylene diamine and terephthaloyl chloride were copolymerized to give a partially N-cyanoethylated poly(p-phenylene terephthalamide) (degree of substitution: 30%), which was soluble in dimethylacetamide-calcium chloride. This solution was wet-spun and the spun fiber was drawn and heat-treated at above 450°C, thereby decyanoethylation occurred to yield a fiber composed substantially of poly(p-phenylene terephthalamide). This fiber showed the following tensile properties: 10.5g/d tenacity, 1.6% elongation and 760g/d initial modulus, respectively.