Characterization Of Elastomer Durability: Insight Into Compression Set And Stress Relaxation

Abstract

This study investigates the thermal aging behaviour of EPDM rubber compounds cured with varying concentrations of peroxide. Mechanical properties such as hardness, tensile strength, elongation at break, compression set, and stress relaxation were evaluated before and after exposure to elevated temperatures. A key innovation of this research is the use of a newly developed testing apparatus for stress relaxation measurements, designed to enable discontinuous long-term testing under controlled deformation and environmental conditions. The device allowed monitoring of stress decay over time, providing deeper insight into the viscoelastic behaviour of rubber material during thermal exposure. Results showed that peroxide concentration significantly influences crosslink density and aging resistance, with optimal performance observed at intermediate peroxide levels. The findings highlight the importance of formulation design and introduce a novel methodology for evaluating long-term elastomer durability.