RUBBER BLEND AND FILLER EFFECTS ON DAMAGE MECHANISMS UNDER MONOTONIC AND FATIGUE LOADING

To appreciate the nature and failure mode of elastomers, it is important to understand their fracture behavior. There are various factors that influence the fracture characteristics of rubber vulcanizates, namely, temperature, strain rate, and type of loading. In this research, fracture behavior of gum and carbon black filled rubber compounds having 100 parts natural rubber (NR), polybutadiene rubber (BR), and 60-40 NR/BR blend is reported. The effect of strain rate, temperature, and carbon black on tensile strength, fracture/tearing energy, and crack growth is detailed. Based on our investigation, we have determined BR to be more sensitive to temperature change than NR. Also, contrasting behavior is observed for gum and filled polymer blends. Tensile and fatigue tests were performed on a universal testing machine and tear and fatigue analyzer, respectively. The tested samples were also examined in the scanning electron microscope to obtain high-resolution imaging of fracture surfaces. The samples tested under monotonic loading provide smoother surfaces by showing the phase separation in comparison with fatigue loading.