Thermal characterization of oil extracted from ethylene–propylene–diene terpolymer residues (EPDM-r)

In this study, extender oil was extracted from automotive scraps of ethylene–propylene–diene terpolymer (EPDM-r). After extraction, the oil was characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). From the TGA analysis at multiple heating rates, the Flynn–Wall–Ozawa (FWO) method was used to determinate the activation energy (Ea) of the degradation process. The FTIR results obtained showed that the extracted oil remained structurally stable after extraction, and no oxidation of the oil was observed. The DSC analysis revealed that the extender oil present in the elastomer composition has the characteristics of paraffinic oil. Thermogravimetric and Ea results showed that the extracted oil had higher thermal stability than the pure oil, since the extraction process can remove some additives and low molecular weight molecules present in the elastomer. Also, the vulcanization and extraction processes can affect the characteristics of the extender oil. This study showed that it is possible to reuse rubber-derivate residues, such as extender oil, without significantly modifying their initial characteristics.