Polycaproamide

[—NH(CH₂)₅CO—]_n, a linear polymer of caprolactam; an aliphatic polyamide. A white, odorless, horny substance. Molecular weight, 10,000–35,000; density, 1.13–1.14 g/cm³ at 20°C; crystallinity, ~ 60 percent; melting point, 225°C.

Polycaproamide is one of the best known polyamides. It is characterized by high wear resistance and mechanical strength —for example, bending strength, ~90 meganewtons per sq m (MN/m²), or ~900 kilograms-force per sq cm (kgf/cm²); impact strength 150–170 kilojoules per sq m, or kgf. cm/cm². Polycaproamide is chemically stable; it is resistant to most solvents (soluble only in concentrated sulfuric and formic acids and in fluorinated alcohols). It is physiologically harmless and is gradually resolved in the human body. At room temperature and normal humidity, polycaproamide absorbs 2–3 percent moisture (maximum, up to 12 percent).

Polycaproamide is produced industrially by polymerization of the monomer and is processed according to the standard methods for polyamides. Large polycaproamide products requiring no mechanical processing are produced by mold polymerization. Polycaproamide is primarily used in fiber manufacture, as well as in the manufacture of various machine parts. Polycaproamide is manufactured under the trade names Kapron and Kaprolon (USSR), Perlon (Federal Republic of Germany), Dederon (German Democratic Republic), Silon (Czechoslovakia), Amilan (Japan), and Nylon-6, Plaskon, and Caprolan (USA).