Study on the Degradation Behavior and Performance Evolution of Rubber in Hot‐Air Aging Environments

ABSTRACT Rubber sealing components in power equipment degrade during long‐term thermal–air aging, which threatens reliability. This study investigates the aging behavior of three representative sealing materials: fluorocarbon rubber (FKM), ethylene propylene diene monomer (EPDM), and nitrile rubber (NBR). Accelerated thermal aging tests are performed at temperatures selected according to material stability (FKM: 150°C–250°C; EPDM and NBR: 95°C–150°C) for 0.5–14 days. Surface morphology, mechanical properties (hardness, stress–strain response, and compression set), and physical properties (density, volume, and mass) are characterized; DMA and TGA are used to evaluate the evolution of thermal properties. All three materials show degradation, with different severities. FKM exhibits only minor changes in hardness, density, and compression set. NBR shows the most pronounced deterioration: after 14 days at 150°C, hardness increases by 31.1%, accompanied by marked volume shrinkage and mass loss. EPDM displays intermediate behavior. An Arrhenius‐based kinetic model based on compression‐set data is established to predict service life, supporting material selection and preventive maintenance for power equipment.