Abstract:
In this study, the modified graphite waste from metals smelting industry was studied in order to use as an additive in natural rubber (NR) composite via oxidation (Hummers method) and reduction of L-ascorbic acid. The obtained graphene was then characterized by CHN analysis, x-ray diffractrometer, fourier transform infrared spectrophotometer, x-ray photoelectron spectroscopy, BET surface area, transmission electron microscopy and four-point probe. The amount of oxygen on the graphene surface was decreased and the graphene sheets became more single layer sheets, resulting in the increase of conductivity (~1.96-fold) compared to graphite (before modification). The electrical conductivity of NR composites with graphene showed the critical concentration at 5 phr (9.06x10-6 S/m) which was comparable with that of NR composite with carbon black Printex XE 2B (5 phr, 8.15x10-6 S/m) and was higher than that of NR composite with carbon black N339 (25 phr, 2.35x10-7 S/m). In addition, the mechanical properties of NR composites with graphene were similar to those of NR composite with carbon black Printex XE 2B and carbon black N339.