Deriving Temperature Derating Factors for Polymer Fatigue Characterization in Engineering Resins
Polymer fatigue temperature derating derives from isothermal S-N curves and viscoelastic shift equations adjusted for cyclic hysteretic heat buildup.
Environmental Aging
Meaning
Degradation processes involve the gradual breakdown of material properties caused by exposure to external factors such as heat, moisture and radiation. The study of environmental aging identifies how long a product remains functional when subjected to the conditions of its operating environment. It stops being relevant once the material has reached a state of complete failure or total stabilization.
Durability varies by chemistry.
Exposure Effect
Chemical bonds within a polymer or coating weaken when hit by ultraviolet light or oxygen. Observations of environmental aging help manufacturers determine the shelf life and service life of their goods. A coating that looks perfect in the factory might peel after six months of sun exposure.
Longevity Prediction
Laboratory chambers simulate years of field use in just a few weeks by increasing the intensity of the stressors. Technicians use environmental aging data to refine the chemical formulation of materials before they go to market. This step is a prerequisite for any product intended for outdoor use.
Service Standard
Modeling the rate of decay allows for the estimation of warranty periods and replacement cycles. Understanding environmental aging prevents the reputation damage and financial loss associated with premature product failure. Reliable aging data ensures that the demonstrations given during the prototype phase match the long term performance of the production units.