Utilization of lignin in carbon fibers preparation offers a sustainable alternative to non-renewable materials as well as value-added co-products for lignocellulosic biorefinery. Primarily, these biorefinery lignin streams are burnt for energy or discarded through landfills and can present a low-cost alternative for carbon fibers. To produce automobile-grade carbon fiber, in this study, biorefinery lignin from wet explosion pretreatment of poplar was chemically modified and blended with polyarylonitrile (PAN) before melt spinning into lignin fibers. Esterification of the polar hydroxyl groups in lignin with acid anhydrides was conducted to enhance the miscibility of carbon fiber precursor. Ionic liquid [BIMIM]Cl as an external plasticizer facilitates melt-spinning of the polymer blends into fibers. Precursor fine filaments were melt spun with a variety of lignin loading levels (0-50%). The influence of esterification and physical blending on the structures and properties of the resulting fiber were evaluated by a series of characterization techniques, including nuclear magnetic resonance (NMR), elementary analysis, Differential scanning electronic microscopy (SEM), scanning differential calorimetry (DSC) and thermogravimetric analysis (TGA). Results indicate that esterification facilitate miscibility of lignin with PAN during blending. The structural and mechanical properties of carbon fibers from lignin/PAN blends were mainly dependent on the lignin content in the blending system. Studies indicated that at 20% blending with lignin, PAN-lignin films showed greater mechanical strength but lower extensibility when compared to 100% PAN. These studies also indicated that the carbon fiber composites produced from PAN-lignin blends (up to 30wt% blending) can be used in several low to medium strength automobile applications such as internal parts, castings and tire frames. The findings from this study provides insights on new avenues to utilize a low-cost biorefinery lignin stream to produce high-value carbon fiber composites resulting in subsequent cost savings for automobile and aircraft industries.

Lowering the carbon foot print of the automobile industry through the in-mixing of modified biorefinery lignin for producing durable interior materials in cars

254th National Meeting (2017)

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