NYLON-6 COPOLYMERS - COPOLYMERIZATION WITH ALPHA-AMINO-ACIDS

Alanine (Ala), leucine (Leu), phenylalanine (Phe) and lysine hydrochloride (Lys . HCl) were incorporated in nylon-6 by melt polycondensation. The reduced specific viscosities of the polymers decreased with increasing comonomer content, in the order Ala > Leu almost-equal-to Phe > Lys . HCl. Glass transition temperature (T(g)), cold crystallization temperature (T(cc)) and melting temperature (T(m)) were measured by differential thermal analysis. T(m) decreased in the order Ala > Leu > Phe much greater than Lys . HCl. T(g) increased slightly with increasing comonomer content. The ease of crystallization, indicated by (T(cc) - T(g)), decreased in the order Ala > Leu > Phe much greater than Lys - HCl. Heat resistance, measured by thermogravimetry, decreased in the same order. Weight loss on alkali hydrolysis increased with increasing comonomer content. The copolymer with Lys . HCl showed the largest weight loss suggesting biodegradability. Acid dyeability could be greatly improved by the incorporation of 1-2 mol% Lys . HCl.