Synthesis of copper-grafted graphite and its effect on properties of natural rubber composites

Conductive polymer composites, which are extensively applied in the fields of sensors, batteries, memory materials, etc. possess some significant properties mainly high electrical conductivity and good mechanical performance. In this study, copper (Cu) was grafted onto the graphite surface according to a chemical process. The Cu-grafted graphite (Cu-g-graphite) was characterized via fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM), where the analysis proved that Cu was successfully grafted onto the graphite surface. Subsequently, natural rubber (NR) composites were prepared by varying the Cu-g-graphite loading from 0 phr (parts per hundred rubber) to 10 phr at 2 phr intervals. The 8 phr Cu-g-graphite filled NR composite showed better physico-mechanical properties in comparison with the other Cu-g-graphite composites and the NR composite prepared without Cu-g-graphite (control). Also, the former composite showed better thermal ageing and electrical conductivity which are requirements for sensor applications. Further, electrical conductivity of the Cu-g-graphite/NR composites prepared with greater than 4 phr loading of Cu-g-graphite was at a high level. Furthermore, the Cu-g-graphite filled NR composites indicated a remarkable improvement in electrical conductivity compared to that of the control. Finally, the performance of NR composite prepared with 8 phr loading of Cu-g-graphite in overall showed a considerable level of applicability for high electrical, thermal and physico-mechanical polymeric applications.