[—HN(CH2)6-NHCO(CH2)4 - CO—]n a linear aliphatic polyamide produced by polycondensation of nylon salt in a melt from hexamethylene diamine, H2N(CH2)6NH2, and adipic acid, HOOC(CH2)4-COOH. Polyhexamethylene adipamide is a white, odorless, horny crystalline polymer with molecular weight 15,000–25,000, density 1.14 g/cm3 at 20°C, crystallinity 40–60 percent, and melting point 264°C. It is the most common polyamide. Polyhexamethylene adipamide has high strength properties (tensile strength, 80 meganewtons per sq m [MN/m2], or 800 kilograms-force per sq cm [kgf/cm2]; bending strength, 100 MN/m2, or 1,000 kgf/cm2) and good abrasion resistance, and it surpasses other aliphatic polyamides in heat resistance (it decomposes at temperatures above 350°C, with the release of CO, CO2, and NH3). It dissolves in concentrated sulfuric, acetic, and formic acids, and in fluorinated alcohols and phenols; it is resistant to the action of oils and alkaline solutions, and has high moisture absorption (water absorption at saturation, 9–10 percent). Polyhexamethylene adipamide is processed using the standard methods for polyamides; it is mainly used in the manufacture of fibers.
Polyhexamethylene adipamide is manufactured under the trade names Anid (USSR); Nylon-66, Zytel–101, and Zytel-106 (USA); Maranyl, Luron, Sutron, and Brulon (Great Britain), and Perlon T, Igamid A, and Anternamid (Federal Republic of Germany).