Influence of Aromatic Content in Rubber Processing Oils on Viscoelastic Behaviour and Mechanical Properties of Styrene-Butadiene-Rubber (SBR) for Tyre Tread Applications

Abstract

In recent years, the increasing concern on the toxicity of highly aromatic oils has been incentive to the development of rubber process oils (RPOs) which are more environmentally-friendly. Many alternative eco-friendly RPOs have been tested with the aims of selecting the most suitable replacement for these highly aromatic oils. As a consequence, in order to achieve both environmental friendliness and effective rubber compounding, the aromatic content in RPOs must be optimised. In the present study, the experiments have been carried out to investigate the effects of aromatic and polycyclic aromatic compounds (PCAs) contents in RPOs on processability and mechanical properties of styrene butadiene rubber (SBR) compounds and vulcanisates. Results obtained suggest that the presence of RPOs leads to a decreased compound viscosity, and thus an enhanced processability. By incorporating the RPOs into SBR compounds, some mechanical properties including elongation at break and tear strength of cured SBR can be improved, particularly for the RPOs with high aromatic content. It is believed to be attributed to the increased compatibility between RPOs and SBR matrix. Nevertheless, the aromatic and PCA contents play little or insignificant role on the crosslink density and bulk viscosity of rubber compounds as well as hardness and compression set of vulcanisates.