Research of thermal oxygen ageing on tensile properties of rubber based on Peck-Yeoh model

Vulcanized natural rubber (NR) is widely used in the industrial areas for absorbing vibrations and shock due to their excellent elastic stability. However, with the increase of exposing to sunlight and oxygen and the change of temperature in their working environment, NR tends to be hardened and lose damping properties. Therefore, the thermal aging effects on the mechanical properties of vulcanized NR need to be considered. In the present work, the effect of thermal oxygen aging on tensile properties of NR is experimentally investigated. Dumbbell-type specimens of different hardness(45/55/65HA) are selected and subjected to thermal oxygen ageing tests at different ageing temperatures (60/70/80/90 °C) for 5,12,24,48 and 72 h.The nominal stress and strain can be measured and recorded by the computer in the process of uniaxial tensile test of aged NR. In the process of analyzing the results of uniaxial tensile test of aged rubber, the modulus of elasticity is chosen as the aging evaluation index, and the hardness, ageing time and temperature are analyzed qualitatively with the aid of the Yeoh hyperelastic constitutive model, while the Peck-Yeoh model is combined to calculate the modulus of elasticity after ageing for the quantitative analysis of the influencing factors. The results of qualitative and quantitative analysis reveal that the NR hardness, ageing temperature and ageing time have a descending order effect on the modulus of elasticity of aged NR. The conclusions drawn from this paper not only provide a basis for the study of the influence of ageing phenomena on the static stiffness properties of rubber elements, but also can give some reference to the design and optimization of the ageing resistance of vulcanized NR.