The use of a nanocellulose-reinforced polyacrylonitrile precursor for the production of carbon fibers

Polyacrylonitrile (PAN) reinforced by nanocellulose (NC) in different concentrations was used as a precursor for carbon fiber production. The NC was prepared by mechanical and chemical treatments. For control of the spinning process, the rheological properties of PAN–NC solutions were investigated. The strong polar interaction between the nitrile groups of PAN and the hydroxyl groups of NC resulted in the formation of an interconnected structure, as shown by the rheological properties. In addition, the NC was an effective reinforcement for PAN precursor because of its high aspect ratio and good interfacial adhesion to the PAN matrix. The spun PAN–NC fibers, containing NC in different concentrations, were oxidatively stabilized at 280 °C in air and carbonized at 1000 °C in nitrogen. Using Raman spectroscopy the Tuinstra–Koenig formula was used to estimate the graphite crystallite size of the resulting carbon fiber and it was found to have been increased by incorporation of the NC. The possibility of a decrease in energy consumption by lowering the carbonization temperature as a result of incorporation of NC was confirmed.