Investigation of Ageing Behaviour of Nitrile-Butadiene Rubber with Added Graphene in an Accelerated Thermal Ageing Environment

In this paper, the thermal ageing of nitrile-butadiene rubber (NBR) reinforced with different graphene (GE) concentrations has been investigated. NBR and NBR-GE composites were exposed to an accelerated thermal ageing environment produced by an air-circulating oven for seven days. The mechanical properties, chemical changes, and thermal stability of ageing samples and neat samples were evaluated. The results showed that the surface damage of NBR was severe and inhomogeneous, and the degree of ageing was most serious on the edge region of the voids, but NBR-GE composites were changed slightly before and after ageing. The tensile strength increased with the increase of GE concentration, up to a maximum value, and decreased with further increases in GE concentration. The GE embedded crosslinked network limited the segment movement of chains in the stretch direction and played a role in the composites properties, and the GE sheets (contained the functional groups of −OH, −C=O and C=C) after ageing. This behaviour may indicate greater interface adhesion between the GE and NBR. In addition, results obtained by thermogravimetric analysis (TGA) indicated that the thermal stability of NBR significantly changed with accelerated thermal ageing environment, but with addition of a certain amount of GE to NBR, the thermal stability of NBR could be improved. The NBR/GE composites exhibited good comprehensive performance with a mass fraction of GE of 10 %. Before and after the thermal ageing, the failure mechanism of NBR-GE composites appeared intergranular and ductile fracture, respectively.