A rapid method to prepare exfoliated graphite using Sri Lankan vein graphite

Abstract

Expansion of graphite using Microwave Irradiation Technique is very promising because it can be performed at room temperature in a short time and less energy consuming with a simple laboratory facility. The aim of this study was to prepare exfoliated graphite from Sri Lankan vein graphite using microwave heating. In the present study, two precursors were prepared by mixing needle platy graphite (NPG) with KMnO4 and HNO3 at 1:1:2 ratio. After that, the first sample was irradiated with microwave just after mixing and while the second one was irradiated after keeping for 12 hrs. As visual observations, the first sample underwent the maximum exfoliation to graphite. Fourier transmission infrared (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and d.c. four probe conductivity characterizations were carried out on the raw and treated samples. Worm-like structure of expanded graphite could be clearly observed from SEM study and the new IR peaks formed during the microwave treatment at 1269cm–1 and 1384cm–1 could be evidently confirmed intercalation of functional groups. The findings of this study should lead to better understanding of the exfoliation of Sri Lankan vein graphite using microwave irradiation technique within a short period of time.