Oxidation and pyrolysis of chitosan as a route for carbon fiber derivation

The oxidation and pyrolysis of chitosan were studied with the aim of obtaining carbon fibers from chitosan fibers. The effect of heat treatment temperature and time as well as pretreatment with ammonium chloride on the conversion process was analyzed. The mechanism for the conversion of chitosan to carbon during oxidation, suggested by FTIR analysis, is one where degradation takes place together with decomposition of the pyranose ring with partial dehydration and deamination. Pretreatment of chitosan improved the carbon yield significantly in the end product. Improved tensile strengths were observed upon pyrolysis. Although the heat treatment temperatures were considerably low, a higher C yield was obtained with chitosan fibers compared to rayon fibers (>20 vs. 15%, respectively). It is concluded that pyrolysis of chitosan fibers in an inert atmosphere can be an alternative method for the production of carbon fibers with regard to pyrolysis of cellulose (rayon) fibers. (C) 2002 Elsevier Science Ltd. All rights reserved.