Everything You Need to Know About Nylon (PA)
Introduction to Nylon (Polyamide, PA)
Nylon — the commercial name for the family of polyamide (PA) polymers — was the world’s first fully synthetic thermoplastic fiber, developed by DuPont in the 1930s. Today, nylon is one of the most widely used engineering thermoplastics globally, valued for its exceptional combination of mechanical strength, toughness, wear resistance, chemical resistance, and processing versatility.
The polyamide family includes numerous grades — PA6, PA66, PA11, PA12, PA46, PA6T, and others — each offering a distinct balance of properties optimized for specific applications across automotive, electronics, textiles, consumer goods, and industrial equipment.
Key Properties of Nylon (PA)
Mechanical Strength and Toughness: Nylon offers high tensile strength, excellent impact resistance, and outstanding fatigue endurance — making it suitable for structural components subject to cyclic loading.
Wear and Friction Resistance: PA is one of the best self-lubricating engineering polymers. Its low friction coefficient and high abrasion resistance make it ideal for gears, bearings, bushings, and sliding wear applications.
Chemical Resistance: Nylon resists aliphatic hydrocarbons, most oils and greases, alkalis, and dilute acids. It is attacked by concentrated mineral acids and certain solvents (alcohols, phenols).
Moisture Absorption: Nylon is hygroscopic — it absorbs moisture from the environment, causing dimensional changes and a reduction in mechanical properties (modulus and strength decrease; toughness increases). This is a critical design and testing consideration.
Thermal Performance: PA66 has a melting point of approximately 260°C; PA6 melts at around 220°C. Heat-stabilized and glass-fiber-reinforced grades significantly extend service temperatures.
Processability: Nylon is readily injection-molded, extruded, blow-molded, and machined — available in a wide range of filled, reinforced, and modified grades.
Testing of Nylon
Testing PA materials covers mechanical, thermal, electrical, and environmental characterization:
Tensile Testing (ASTM D638): Evaluates tensile strength, elongation, and modulus — with testing performed at both dry and conditioned (moisture-equilibrated) states to capture the full property range.
Impact Testing (ASTM D256 — Izod, D6110 — Charpy): Notched impact values quantify toughness for design and material comparison.
Flexural Testing (ASTM D790): Flexural strength and modulus under bending load — critical for structural and semi-structural applications.
Moisture Absorption Testing (ASTM D570): Quantifies water uptake across different humidity levels and temperatures, providing data for dimensional change and property-correction calculations.
Heat Deflection Temperature (ASTM D648): Measures the temperature at which nylon begins to deflect under a defined flexural load — important for under-hood, electrical, and high-temperature service applications.
Wear and Friction Testing (ASTM D3702, G99): Evaluates sliding wear rate and friction coefficient for tribological applications.
Flammability (UL 94, ASTM D635): Rates the flame retardancy of nylon grades for electrical and electronic applications.
Industry Applications
Automotive: Engine covers, air intake manifolds, fuel system components, cable ties, connectors, and gear selector forks use nylon for its thermal performance, chemical resistance, and weight-saving potential versus metals.
Electronics: Nylon is widely used for connector housings, cable ties, circuit breaker housings, and coil formers due to its electrical insulation properties and dimensional stability under moderate heat.
Textiles and Apparel: PA6 and PA66 fibers form the basis of nylon textiles — hosiery, sportswear, outdoor gear, and technical fabrics — valued for strength, elasticity, and abrasion resistance.
Industrial Equipment: Nylon gears, bearings, bushings, and rollers replace metal components where self-lubrication, noise reduction, and weight savings are priorities.
Consumer Goods: Toothbrush bristles, zip fasteners, sports equipment, and packaging films represent the wide range of consumer products that use nylon.
Conclusion
Nylon’s combination of mechanical strength, wear resistance, chemical compatibility, and processing versatility makes it one of the most specified engineering thermoplastics across automotive, electronics, and industrial applications — but its hygroscopic nature means that the moisture conditioning state must be defined and controlled in every mechanical test. Comprehensive characterization per ASTM D638, D570, D648, and D3702 in both dry and conditioned states gives design engineers the full property picture needed to select the right polyamide grade and predict real-world dimensional stability and structural performance under service humidity and temperature conditions.
Why Choose Infinita Lab for Nylon Testing?
Infinita Lab offers comprehensive nylon (polyamide) testing services with a nationwide network of accredited facilities across the USA. Our advanced equipment and expert professionals deliver highly accurate, prompt test results in both dry and conditioned states, helping businesses achieve quality compliance and product reliability. From mechanical and thermal characterization to moisture absorption and wear testing, Infinita Lab is your single point of contact for all PA testing needs.
Looking for a trusted partner to achieve your research goals? Schedule a meeting with us, send us a request, or call us at (888) 878-3090 to learn more about our services and how we can support you. Request a Quote.
Frequently Asked Questions
What is the difference between PA6 and PA66? PA66 has a higher melting point (~260°C vs ~220°C), slightly higher tensile strength and modulus, and somewhat lower moisture absorption than PA6. PA6 generally offers better impact resistance and easier processing. Both are widely used, with the choice depending on the specific thermal, mechanical, and cost requirements.
How does moisture absorption affect nylon properties? Moisture acts as a plasticizer in nylon, reducing stiffness and tensile strength but significantly improving toughness and impact resistance. Dry-as-molded PA66 may have twice the modulus of its moisture-equilibrated counterpart. All structural designs with nylon should account for both dry and conditioned property states.
Can nylon be reinforced to improve mechanical properties? Yes. Glass fiber reinforced nylon (typically 15–50% GF) dramatically increases tensile strength, modulus, and heat deflection temperature while reducing moisture sensitivity. Carbon fiber, mineral fillers, and lubricant additives provide further property tailoring.
What chemicals are incompatible with nylon? Concentrated mineral acids (HCl, H₂SO₄, HNO₃), strong oxidizing agents, and certain alcohols and phenols can attack nylon. Design engineers must evaluate chemical compatibility carefully, especially for fluid-contact applications.
What ASTM standards apply to nylon testing? Key standards include ASTM D638 (tensile), ASTM D790 (flexural), ASTM D256 (impact), ASTM D570 (moisture absorption), ASTM D648 (heat deflection temperature), and UL 94 (flammability).
