Oxidation can change a rubber compound's molecular structure and mechanical properties. Chain scission and additional crosslinking may both occur, with their relative effects depending on the formulation and exposure conditions.
Spectroscopic analysis can help identify chemical changes. Mechanical measurements, such as changes in hardness or tensile properties, provide different information. A softer or harder surface alone does not establish the full reaction mechanism.
Comparative testing should identify the compound, specimen geometry, temperature, duration and oxygen exposure. If stress-relaxation results are used, explain whether loading is continuous or intermittent and report the method. Use the measured changes to assess application requirements; do not infer a fixed service life from an unreferenced curve or a generic material name.
