A Study on a Visualization of Fatigue Behavior near the Glass Transition Region

This study aimed to visualize crack initiation and propagation of rubber at low temperatures. Typical fatigue behavior such as cracking at only the compressed part of rubber products like dustcovers during oscillation tests at ultra-low temperatures have been reported [1]. Rubber products are usually used at temperatures where good rubber elasticity can be obtained. However, in some cases, they are used near glass transition temperatures at which rubber elasticity is poor. Fatigue failures of rubbers generally occur due to existing defects in the rubber material, and rubber tends to fracture easily near glass transition temperatures due to cracking on the surface of the compressed side of the rubber. The observation of the crack initiation process of rubber is difficult at low temperatures because the fracture patterns on rubber disappear when elasticity is recovered at room temperature. For this reason, in this study, we aimed to observe the fatigue behavior of rubber near the glass transition temperature by testing rubber materials whose T_g is above room temperature.