Thermogravimetric Characteristics of Coal-derived Graphene Oxide Composites via Ball Milling

摘要

Thermal analysis techniques are perfect tools to investigate the thermal stability (physical properties) as well as the reaction (chemical properties) of studied materials. Thermal gravimetric analysis (TGA) is one of the thermal analysis techniques to study materials and their changes in both physical and chemical properties under a well-controlled temperature profile. This study investigated the thermal stability and potential chemical reactions of selected materials, including coal, char, and graphite mixed with Potassium Permanganate (PM), before and after ball-milling. Both coal and char samples were mixed with PM. However, some graphite samples were mixed with PM and others were not. The ball-milling method for material preparations was conducted under an air atmosphere, and the TGA method for the material characterization was conducted under a nitrogen atmosphere. Our experiment supported the effectiveness of the ball-milling method for the production of graphene composites from any carbon source. The thermogravimetric characterization of the ball-milled products showed some similarity in their characteristics between ball-milled graphite-derived products and ball-milled coal-derived or char-derived products. Other advanced spectroscopic characterizations revealed that there were likely the formations of layered graphene-like composites, which appeared thermally-stable until the temperatures approached and exceeded 700 °C. This also implied the usefulness of this thermal analysis method for the characterization of graphene. Further investigations will be continued to purify the ball-milled carbon-derived or char-derived products for the confirmation of the viability of thermal analysis techniques, as well as a ball-milling method of graphene synthesis using a variety of carbon sources.