PA - Polyamide (Nylon)

PA6 and PA66 are the two most common polyamide types. PA6 (polycaprolactam) has a lower melting point (220°C), easier processing, better surface finish, and slightly higher impact strength. PA66 (polyhexamethylene adipamide) has a higher melting point (260°C), greater rigidity, higher tensile strength, and superior heat resistance. PA66 is preferred for under-hood automotive parts and high-temperature electrical components, while PA6 is favored for consumer goods, extrusion applications, and parts requiring excellent aesthetics.

Syntex America supplies a comprehensive range of polyamide grades including unfilled PA6 and PA66 for general-purpose molding, glass-fiber-reinforced PA (15–50% GF) for structural applications, mineral-filled PA for dimensional precision, impact-modified PA for low-temperature toughness, PA12 for fuel system and tubing applications, and heat-stabilized and UV-stabilized grades for demanding service environments.

Polyamide is hygroscopic, meaning it readily absorbs moisture from the atmosphere. Excess moisture (above 0.2%) causes hydrolytic degradation of the polymer chain during melt processing, resulting in reduced molecular weight, lower mechanical properties, surface defects (splay, silver streaks), and inconsistent part quality. Proper drying using a desiccant dryer at 80–90°C for 4–6 hours is essential before processing any polyamide resin.

Polyamide is used across virtually all major industries. Automotive (under-hood components, connectors, structural parts) is the largest market, followed by electrical and electronics (connectors, circuit breakers, terminal blocks), industrial machinery (gears, bearings, conveyor components), consumer goods (sports equipment, power tools, housewares), and transportation (fuel lines, brake tubing, cable sheathing). Glass-reinforced PA grades are increasingly replacing metals in structural automotive components for weight reduction.

Polyamide absorbs moisture from its environment, which affects part dimensions, mechanical properties, and electrical characteristics. Moisture absorption causes dimensional swelling (up to 2.5% for PA6 at saturation), reduces tensile strength and stiffness, but increases impact resistance and elongation at break. For applications requiring dimensional stability in humid environments, PA12 (0.25% absorption) or mineral-filled grades are preferred. Glass-fiber-reinforced grades also show reduced sensitivity to moisture effects.