Thermal aging depends on more than the name of the base rubber. Polymer structure, cure system, fillers, protective additives and service conditions all affect the response of a finished grommet.
Temperature and exposure duration must be considered together. Oxygen availability, part thickness and mechanical loading can also influence the result. A short-term temperature limit should not be treated as a continuous operating rating.
When reviewing aging data, identify the actual compound and the test conditions. Compare relevant changes in strength, hardness, deformation or sealing behavior with the application's acceptance criteria. Silicone rubber and carbon-chain elastomers have different structures, but neither should be assigned a universal degradation threshold without supporting data for the selected grade.
