On the evolution of the viscoelastic properties and its microstructural/chemical origin in filled NBR subjected to coupled thermal and mechanical loads

This study deals with the effect of coupled thermal and cyclic mechanical loadings on the viscoelastic response of carbon black filled nitrile rubber. For this purpose, cyclic loading tests were performed at different temperatures by means of Dynamic Mechanical and Thermal Analysis (DMTA). The type and level of the thermomechanical loadings applied were chosen in order to determine the relative contribution of each of the mechanical and thermal loadings (and their coupling) to the viscoelastic response during the cyclic tests. X-ray Photoelectron Spectroscopy (XPS) and Fourier Transformed Infrared spectroscopy (FTIR) analyses were also carried out to track the change in the chemical structure corresponding to the evolution in the viscoelastic response. First, results obtained show that due to the crosslink increase, the storage modulus increases with the number of cycles. It is also observed that temperature amplifies this phenomenon. Second, the cyclic mechanical loading is found to significantly amplify the effect of temperature.