Effect of Thermo‐Oxidative, Ultraviolet, and Ozone Aging on Nonlinear Viscoelasticity of Carbon Black‐Filled Rubber Based on Crosslink Density Evolution

Carbon black (CB)‐filled rubber has been extensively used in many engineering fields. In the service process, CB‐filled rubber tends to experience mechanical properties degradation resulting from environmental factors, such as thermo‐oxidative, ultraviolet, and ozone aging. To better understand the degradation mechanism, dynamic mechanical analysis tests were conducted, and the Maier‐Göritz (MG) model was used to analyze the crosslink density evolution with aging time. It was found that thermo‐oxidative, ultraviolet, and ozone aging had a great effect on the Payne effect and hysteresis loss. Based on experimental results, the MG model was used to simulate the Payne effect under various aging conditions, and the constants of the MG model were obtained. It was observed that the simulating results were in good accordance with the experimental ones. In addition, a novel method was proposed to evaluate the crosslink density evolution with aging time based on the constants of the MG model. The reliability of the proposed method was verified by the existing results, which indicated that the crosslink density was one of the dominant factors affecting the Payne effect and hysteresis loss of CB‐filled rubber in the process of aging.