Bioconversion of Carbon Fiber
Due to carbon fibers excellent strength to weight ratio it has found uses in many demanding aerospace and other high-end applications. The high cost of polyacrylonitrile (PAN) based carbon fiber, $10–20 per pound, has limited its use in the automotive industry as a way to decrease vehicle weight and by doing so, increasing the fuel economy and efficiency. The use of PAN as a precursor in the production of current carbon fiber is responsible for 50% of the cost associated in is manufacture. By incorporating lignin, the second most abundant natural polymer and byproduct of the paper industry, the cost of carbon fiber could be reduced to as little as $3-5 per pound. These compounded fibers were experimentally produced using the gel spinning and melt processing methods. The gel spinning method used a combination of PAN, lignin, Dimethyl Sulfoxide, and water to produce long continuous fibers, as well as investigating how changing certain parameters of the method affect the resulting product. Along with this method a melt processing method was examined several different additives were incorporated into polymer blends that were then comparison molded. From both processing methods samples were then taken through the same pyrolysis process used to make PAN based carbon fiber. The resulting samples were evaluated using RAMAN spectroscopy to determine their composition.
Once samples were successfully produced the fibers were evaluated using multiple material testing machines to understand the fibers’ chemical and structural make up. The fibers were analyzed using differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, energy dispersion spectrometry, and RAMAN spectroscopy. Upon gathering these results, it was confirmed that samples produced form both production methods had the same composition as commercial available carbon fiber. The quality of the gel spun fibers needs to be improved, especially by decreasing fiber void content and processing at higher graphitization temperatures. The melt processing method can currently be used to compression mold panels, but is still unable to achieve the desired melt flow properties to allow for fiber formation.