nylon66

Nylon 66, also known as polyamide 66 (PA66), is a widely used engineering thermoplastic and, in fiber form, a textile material. It is produced by polycondensation of hexamethylenediamine and adipic acid, yielding repeating units linked by amide bonds: -NH-(CH2)6-NH-CO-(CH2)4-CO-, n. The polymer is semicrystalline and has a relatively high melting point, typically around 260°C, and a glass transition in the 50°C range. It offers high tensile strength, stiffness, and exceptional abrasion resistance, along with good heat resistance and chemical resistance to oils and fuels. It is also relatively dimensionally stable when dry but is hygroscopic, absorbing moisture from the environment, which can soften the material and lower dimensional stability and mechanical properties; drying and moisture control are important during processing and service.

Processing and handling: PA66 is melt-processed by standard methods such as injection molding, extrusion, and blow molding. It requires higher processing temperatures than some nylons due to its higher crystallinity and melting point. Drying before processing is commonly recommended, typically around 80–120°C depending on moisture content.

Applications: It is used in automotive powertrain and under-hood components, electrical connectors, housings, gears, bearings, and piping. In fiber form, PA66 is used for textiles, carpets, and industrial yarns, valued for strength and heat resistance.