Study on the interaction between fluoroelastomer and silica: Characterizations

Abstract Due to their excellent chemical stability, fluoroelastomers have been widely used in various severe circumstances since birth. At present, carbon blacks and inorganic fillers are the two most prominent reinforcing agents in fluoroelastomers. However, despite the rise of silica in the rubber industry, it is still difficult to apply this non‐carbon filler alone as a reinforcing agent in fluoroelastomer. Research on the interaction between silica and fluoroelastomer is even less and not systematical. Based on the above, we analyzed the interaction between silica and fluoroelastomer under different conditions through x‐ray photoelectron spectroscopy (XPS), Fourier‐transform infrared spectroscopy, bound rubber (BR) content analysis and rheological properties, and so forth. The interaction between fluoroelastomer and silica can be characterized by the binding energy variation at different temperatures (especially 260°C the new peak at about 685 eV) and wavenumber shift of Si–OH and Si–O–Si in XPS and infrared (IR) analysis, respectively. The BR content varied with loading, temperature, and atmosphere, reflecting the strength of the interaction from a macro perspective. The evolution of the rheological curves of different recipes and test conditions correlate closely with the results of XPS, IR, and BR content analysis, which also shows the sensitive response of polymer‐filler interaction to temperature and load. The observation results of transmission electron microscopy (TEM) directly demonstrate the differences in the dispersion of fillers at different temperatures. The proposed mechanism of fluoroelastomer–silica interaction mode will provide us with novel approaches to the applications of silica in the fluorine industry. Highlights X‐ray photoelectron spectroscopy analysis indicates new fluorine species on the interfaces. Infrared and bound rubber tests verify the fluoroelastomer–silica interactions. Rheological curves reflect the interaction strength.