Thermal Properties and Structure Study of Lignin-based Carbon Fiber
This work reports on the thermal properties and micro-structure study of lignin-based carbon fibers (CFs) at the microscale. The thermal conductivity (k) of the CFs varies from 1.83 to 2.63 W/m·K at room temperature (RT). The thermal diffusivity of the CFs changes a little as temperature goes down from RT to 10 K, which means that the thermal transport in samples is dominant by the phonon-boundary scattering. With this mechanism, the phonon mean free path due to boundary scattering (?eff) could be estimated. The ?eff of three samples are determined to be 1.23, 1.1 and 1.18 nm based on the residual thermal reffusivity at the 0 K limit. The Raman spectrum of the CFs indicates the high disorder degree and the existence of graphite oxide (GO) in the lignin-based CFs. The lattice spacing between two carbon layers determined by X-ray diffraction is 3.777 Å, which also proves the existence of GO in our samples. The k of the lignin-based CFs is increased by ten folds after being annealed at ~2800 K, reaching a value of 24 W/m·K. After being annealed, the typical Raman spectrum of single-layered graphene is studied, explaining the thermal conductivity increase of the sample.
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Jing Liu (POC,Primary Presenter,Author), Iowa State Univeristy, firstname.lastname@example.org;
Xinwei Wang (Co-Author), Iowa State University, email@example.com ;