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- Bengtsson, Andreas, et al.
(author)
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Continuous Stabilization and Carbonization of a Lignin–Cellulose Precursor to Carbon Fiber
- 2022
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In: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 7:19, s. 16793-16802
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Journal article (peer-reviewed)abstract
- : The demand for carbon fibers (CFs) based onrenewable raw materials as the reinforcing fiber in composites forlightweight applications is growing. Lignin−cellulose precursorfibers (PFs) are a promising alternative, but so far, there is limitedknowledge of how to continuously convert these PFs underindustrial-like conditions into CFs. Continuous conversion is vitalfor the industrial production of CFs. In this work, we havecompared the continuous conversion of lignin−cellulose PFs (50wt % softwood kraft lignin and 50 wt % dissolving-grade kraft pulp)with batchwise conversion. The PFs were successfully stabilizedand carbonized continuously over a total time of 1.0−1.5 h,comparable to the industrial production of CFs from polyacrylonitrile. CFs derived continuously at 1000 °C with a relative stretch of−10% (fiber contraction) had a conversion yield of 29 wt %, a diameter of 12−15 μm, a Young’s modulus of 46−51 GPa, and atensile strength of 710−920 MPa. In comparison, CFs obtained at 1000 °C via batchwise conversion (12−15 μm diameter) with arelative stretch of 0% and a conversion time of 7 h (due to the low heating and cooling rates) had a higher conversion yield of 34 wt%, a higher Young’s modulus (63−67 GPa) but a similar tensile strength (800−920 MPa). This suggests that the Young’s moduluscan be improved by the optimization of the fiber tension, residence time, and temperature profile during continuous conversion,while a higher tensile strength can be achieved by reducing the fiber diameter as it minimizes the risk of critical defects.
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