Insights into the effects of high-temperature lubricating oils on the aging behavior and degradation mechanism of fluoroelastomers

The aging behavior and degradation mechanism of fluoroelastomers (FKM) after exposure to thermal air, commercial lubricating oil, and the corresponding base oil at elevated temperatures were investigated. The FKMs immersed in oil and exposed to air are denoted by FKM-O and FKM-A, respectively. The crosslinking densities of the samples were determined by equilibrium swelling and dynamic mechanical analyses, and the results were different. Compared to the performances of FKM-A, noticeable changes in the mechanical and swelling performances of FKM-O were observed, attributed to the severe deterioration induced by both the lubricating oil and the high-temperature. The FTIR results revealed that the dehydrofluorination induced by the oil caused the fracture of the C-F bonds, and the degradation of the oil itself exerted negative impacts on the properties of the FKM. The findings of this study will facilitate the development of FKMs with degradation-resistant properties for various applications.