A Study on Functionalization of Waste Tire Rubber Powder Through Ozonization

In this study, ozone treatment was used to improve the surface wettability of waste tire rubber (WTR) powders. Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) were performed in order to characterize the surface composition of the treated samples. The progress of surface modification was also monitored by contact angle measurements of different test liquids (water and liquid paraffin). The surface energy values were evaluated in terms of the Owens’ method and the contact angle data were compared with the results obtained by the surface analytical methods (i.e. FTIR and XPS measurements). These results showed that ozone treatment lead to a remarkable decrease in water contact angle owing to the implantation of oxygen-containing functional groups. Using XPS and FTIR, the oxygen-containing groups can be identified as C–O, O–C=O and C=O. With prolongation of ozone treatment time, WTR exhibited increasing oxygen-containing groups, surface energy and wettability.