Reinforcing Efficiency of Pyrolyzed Spent Coffee Ground in Styrene-Butadiene Rubber

This research aimed to study the reinforcing efficiency of pyrolyzed spent coffee ground (SCG) in styrene-butadiene rubber (SBR). The SCG was initially treated at elevated temperatures of 700 °C and 900 °C (under nitrogen gas) before being characterized by various techniques, e.g., particle size analysis, Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. After being added into SBR, properties of the rubber compounds and vulcanizates were determined. The results showed that pyrolysis of SCG at 700 °C and 900 °C significantly reduced the average particle size from 39.8 µm to 27.3 µm and 25.3 µm, respectively. The addition of pyrolyzed SCG into SBR resulted in the increases of both rubber-filler interaction, as evidenced from the increase of bound rubber content, and crosslink density, leading to the improvement of mechanical properties of the rubber vulcanizates when compared with the addition of untreated SCG.[Figure not available: see fulltext.]