Non-structural applications of Ioncell® carbon fibers

Abstract

Engineering cellulose-based materials has received much attention to relieve the burden of CO2 emissions and dependence on non-renewable resources. In particular, as this thesis demonstrates, cellulose pyrolysis represents a potential route to fabricate carbon fibers (CF), which can alleviate the global demand for natural graphite and synthetic carbons. Nevertheless, understanding cellulose thermal decomposition presents many knowledge gaps; filling them is necessary to tailor CF that display specific nanostructures, functionalities, and textures. The work hereafter examined the carbonization yield y1 of Ioncell® cellulose fibers. y1 is a constraint hindering the scalability of cellulose as a CF precursor. This thesis displays how experimental design can assist in modeling the influence of diammonium hydrogen phosphate (DAP), CO2 activation time, and lignin (BL) on cellulose y1. DAP and BL are factors known for increasing y1 as they inhibit forming small volatile carbon compounds during cellulose pyrolysis. However, this study showed that, when combined, the effect of DAP and BL on y1 are non-additive. Assessing the performance of Ioncell CF in non-structural applications consisted of enhancing their texture and surface chemistry. This thesis bridged gaps in carbon materials science during the CF characterization. For example, the manuscript adapts and verifies tools and methods developed by third-parties to ease the mathematical treatment of adsorption isotherms and Raman spectra. All in all, Ioncell CF had relatively high CO2 adsorptions (~2 mmol/g) at unsaturated pressure conditions. These biobased CF were microporous materials, and they may be crucial in gas separation membranes and storage systems.