Graft polymerization of styrene onto waste rubber powder and surface characterization of graft copolymer

The surface of waste rubber powder (WRP) was graft-modified with styrene (St) by bulk polymerization method. The effects of styrene content, initiator mass, time of reaction, and temperature on the graft efficiency were investigated. The results showed that the graft efficiency (%) was highest when 89 wt% styrene and 0.11 g of initiator were added for reaction time of 25 h at 85 °C. The surface of graft-modified rubber powder was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy dispersive X-ray (EDXS) analysis, and thermogravimetric (TG/DTG) analysis. The results showed that polystyrene (PS) was grafted onto waste rubber powder, which formed a WRP/PS core–shell structure.