They are inert to biological attack, and have adequate electrical properties for most voltages and frequencies. The crystalline structure of nylons, which can be controlled to some degree in processing, affects stiffness, strength, and heat resistance. Low crystallinity imparts greater toughness, elongation, and impact resistance, but at the sacrifice of tensile strength and stiifness. Moisture absorption leads to dimensional and property changes dependent upon the equilibrium level absorbed. Weatherability will be reduced unless UV stabilizers are incorporated into the formulation.
Carbon black is the most commonly used UV stabilizer.
Carbon black lowers the ductility and toughness as a trade-off for UV stability. Nylons have good resistance to creep and cold flow compared to many less rigid thermoplastics. Creep can be calculated from long-term apparent modulus under load data.