What is PA?

 

PA, short for polyamide and commonly known as nylon, is a class of high molecular compounds with repeating amide groups in the main molecular chain. It is also one of the earliest engineering plastics to achieve industrial production.

 

From the perspective of production technology, the core of PA preparation is polymerization reaction, with two mainstream methods: first, polycondensation reaction—for example, PA66 is synthesized from two monomers, adipic acid and hexamethylenediamine, with water molecules produced as a byproduct during the reaction; second, ring-opening polymerization—a typical example is PA6, which uses caprolactam as the monomer and opens its cyclic structure under the action of a catalyst to form linear polymer chains. After polymerization, the product is pelletized to obtain PA resin, which is then processed into various products through secondary manufacturing processes such as extrusion, injection molding and spinning according to subsequent application requirements.

 

PA boasts excellent comprehensive properties: it has high mechanical strength and good toughness, capable of withstanding large impact and tensile forces; it features outstanding wear resistance and self-lubricity with a low friction coefficient, making it suitable for manufacturing transmission components like gears and bearings; meanwhile, it is resistant to oils and organic solvents, hence widely applied in the chemical and automotive industries.

 

PA has several common grades based on different polymer monomers, such as PA6, PA66 and PA12. Different grades vary slightly in melting point and rigidity, and are suited for distinct scenarios. PA6 excels in flexibility and is mostly used in fiber spinning and hoses; PA66 has higher rigidity and is often adopted as the raw material for auto parts around the engine.

 

Nevertheless, PA has obvious drawbacks: it has high water absorption, which leads to reduced dimensional stability after water uptake. In some scenarios, its performance needs to be optimized through methods like glass fiber reinforcement and filling modification to expand its application scope.

 

 

 

YANMEI · Application Cases

Widely applied in industries such as electronics, batteries, automotive, cables, machinery, and drones.