polyamidebased

Polyamide-based materials are polymers that feature amide linkages in their repeat units. They include aliphatic polyamides (nylons) such as nylon-6, nylon-6,6, and nylon-11, as well as aramids like Kevlar and Nomex, which impart high strength and temperature resistance.

Most polyamides are formed by condensation of diamines with dicarboxylic acids (example nylon-6,6) or by ring-opening polymerization of caprolactam (nylon-6). The amide bonds enable strong intermolecular hydrogen bonding, contributing to mechanical performance but also leading to moisture absorption.

Key properties: high tensile strength, stiffness, abrasion resistance, good chemical resistance; thermal stability varies; moisture uptake can soften polymers; crystallinity influences stiffness and barrier properties; processing techniques include extrusion, injection molding, and 3D printing with various grades.

Applications: fibers and textiles (carpets, tire cords), engineering plastics for automotive and electronics, moldings, coatings, and composite matrices with glass or carbon fibers; specialized uses include high-temperature aramids for protective gear and aerospace.

Environmental and sustainability notes: some polyamides are bio-based (PA11 and PA610 from castor oil; PA12 derived from laurolactam), and recycling can be mechanical or chemical. However, most polyamides are not readily biodegradable, and end-of-life management is a consideration.