Structure and properties of deeply oxidized waster rubber crumb through long time ozonization

Deeply oxidization of waster rubber crumb (WRC) by ozone treatment was carried out at room temperature with long time exposure. Gel content measurement, TG/DTG (thermogravimetric) analysis, ATR-FTIR (attenuated total reflectance-Fourier transform infrared) spectroscopy, XPS (X-ray photoelectron spectroscopy) and mixing properties tests were used to investigate the structure and properties of deeply oxidized WRC. After ozone oxidation, the gel content of WRC decreased dramatically in the first 3 h and then decreased slowly with prolonging the oxidation time. TG/DTG results showed that few low molecule weight materials were produced although ozone did destroy some cross-linking networks by oxidizing decomposition. ATR-FTIR and XPS spectrum showed the increase of oxygen-containing groups in WRC, indicating that oxidation reaction between ozone and WRC happened. Deeply oxidized WRC could form a uniform plate under pressure and heat due to regaining part of the flowability.