Conversion of Paper and Oil Industry Byproducts to Graphitic Material

Abstract

Many different graphitic materials have become integral in modern society for the past couple of decades. Advances in developing carbon fibers, graphene, and graphene oxide have improved the amount of the material that can be produced in bulk as well as improving different properties of the material such as increasing its mechanical strength carbon fiber or improving the conductivity of graphene oxide. Carbon fiber has seen use in both commercial and industrial applications ranging from electronics to fuselages, which can have impressive electrical and mechanical properties combined with its relatively low-density compared to traditional metals. Both graphene and graphene oxide have seen advances in many different areas, including high-performance sports gear, flexible electronics, and even use in space equipment. However, there is an opportunity to explore different sources to produce graphitic materials, many derived from renewable materials. Thus, finding alternative precursors to meet the demand for graphitic products, whether through renewable biomass or industrial waste, is crucial. One precursor that has gained broad attention is lignin, a byproduct of the pulp and paper industry. Lignin is one of the most common naturally occurring macromolecules derived from three different phenolic alcohols, and there has been research into developing various products from lignin, including carbon fiber. Another precursor is asphaltene, which is a byproduct of the asphalt industry. While asphaltene is not a renewable material like lignin, it has limited applications, making it a waste product. The oil industry can become more sustainable by converting the material into graphitic carbon, like graphene. In the first chapter, background information is discussed on various graphitic carbons, their applications in the market, and the potential for lignin and asphaltene to be converted into carbon fiber, graphene, and graphene oxide. Chapter II details the development of lignin-based carbon microfibers and a novel method of using different surface treatments to control the specific capacitance of the carbon fibers. Characterization showed that the specific capacitance is increased by activating the carbon and/or growing Ni(OH)2 nanocrystals on the surface. The next chapter studies a new method of producing graphene oxide (GO) from lignin using vermiculite as a scaffold. This is one of the few methods of producing graphene oxide from lignin. Various characterization techniques were performed on the material, confirming that it is graphene oxide. In addition, a reduction reaction using ascorbic acid was performed to produce reduced graphene oxide (RGO), a semiconductive material. Chapter IV investigates the usage of a unique form of lignin called alkaline lignin to develop graphene using an iron catalyst. Characterization showed that the material was graphitic and incorporated into electrospun PVDF fibers. These fibers were studied for their piezoelectric properties, where it was demonstrated that they could produce a voltage when mechanical force was applied to them. Chapter V demonstrated a novel application of asphaltene-based graphene as a filler for UV-curable resin. Mechanical analysis showed that the graphene improved the flexural properties and the thermal stability of the resin. Chapter VI contains potential future work for these projects.