Nylon materials exhibit different physical and chemical properties at various temperatures.
Here's how nylon reacts under different temperature conditions:
At Low Temperatures: Nylon becomes more brittle and susceptible to cracking. For instance, the brittleness temperature of dry Nylon 6,6 is around -80°C, and it increases to -65°C when the relative humidity is at 50%.
At Room Temperature: Nylon typically exhibits good toughness and impact resistance.
At High Temperatures: Nylon gradually loses its strength and rigidity, becoming soft and malleable. For example, the melting point of Nylon 6 is around 220°C (428°F), and for Nylon 66, it's about 265°C (509°F). When temperatures approach or exceed the melting point, nylon may experience permanent deformation or melting.
Glass Transition Temperature: The glass transition temperatures for most nylons range between 40°C and 70°C (104°F to 158°F). Within this temperature range, nylon transitions from a brittle, glassy state to a more ductile and flexible state.
During Processing: The processing temperature of nylon must be carefully controlled. For example, the mold temperature for nylon is recommended to be maintained between 80°C and 120°C (176°F and 248°F) to balance the cycle time and mechanical properties of the molded parts.
Thermal Stability: Prolonged exposure to high temperatures can lead to thermal degradation, such as discoloration, loss of mechanical properties, and even rupture.
Moisture Absorption: Nylon materials are hygroscopic, and absorbing moisture can cause dimensional changes, affecting their mechanical properties.
Long-term Sun Exposure: Nylon has relatively weak resistance to UV light, and it can become brittle and degrade under long-term sun exposure.
Heat Treatment: Under high temperatures and certain conditions, nylon can undergo heat treatment, such as heat setting or melting, to improve its properties.
Flammability: Nylon is not highly flammable, but its flame resistance can be improved by adding flame retardants in some cases.
It's important to note that the specific reactions of nylon also depend on its type, processing methods, and the presence of additives.
