Preparation of Cellulose-Derived Carbon Fibers Using a New Reduced-Pressure Stabilization Method

Abstract

We present a new continuous stabilization process for cellulose-derived carbon fibers (CFs) with mechanical properties rivaling those of polyacrylonitrilederived CFs. The novel process enables optimum control over the stabilization process. The effects of process temperature and dwell time on the structure and mechanical properties of the stabilized fibers were investigated by elemental analysis, wide-angle Xray scattering, infrared spectroscopy, scanning electron microscopy, and tensile testing. Laboratory-scale carbonization trials of the stabilized fibers were accomplished in a continuous process at 1400 °C. Received CFs had tensile strengths up to 2.8 GPa and Young's moduli up to 112 GPa. By adjusting the stabilization conditions, the mechanical properties of the resulting CFs can be tuned.

Carbon Fibers from Wet-Spun Cellulose-Lignin Precursors Using the Cold Alkali Process

“…Despite the low intrinsic viscosity (260 mL/g) of the cellulose pulp and the relatively low precursor tensile properties obtained with the cold NaOH(aq) process, the resultant CFs had tensile properties in the same range as those made from air-gap-spun cellulose-lignin precursors using ionic liquids and neat cellulosic rayon precursors [8,19]. The tensile properties were, however, lower than those recently reported for CFs from high-tenacity rayon and ionic liquid-based cellulose precursors prepared via a reducedpressure stabilization method [47]. Vocht et al (2022) used a stabilization method which made it possible to achieve cellulose-based CFs with higher tensile properties, and this non-conventional stabilization method should be explored for the precursors prepared in the present work.…”

Lignin/Poly(vinylpyrrolidone) Multifilament Fibers Dry‐Spun from Water as Carbon Fiber Precursors

“…than the PAN‐based Toray T300CF (Table 3), which is also reflected by lower L c and P.O., and higher L a and d 002 values. [ 34 ]…”

“…than the PANbased Toray T300CF (Table 3), which is also reflected by lower L c and P.O., and higher L a and d 002 values. [34] As displayed in Figure S11, Supporting Information, the Raman spectra of the CFs displayed the typical D-and G-bands. The intensity ratio (I D /I G ) of the defect band (D1 band, 1340 cm −1 ) and the graphite band (G band, 1590 cm −1 ) depends on the carbonization temperature and provides information about defects in the graphite structure.…”

“…Table 4 provides an overview of the Weibull strengths (𝜎 0 ) and the Weibull modulus (m) of the fabricated CFs, the corresponding plots are shown in Figure S7, Supporting Information. The larger the value, the more uniformly the defects are distributed in the CF, that is, the better the ho- [3,34,38] In line with the highest values for tensile strength and Yong's modulus, CF1400.3 (DR 1.05) showed the highest m-value of 5.1, which indicates that these fibers had a higher homogeneity compared to CF1400 (DR 1.00) with m = 4.2 and CF1400.2 (DR 1.01) with m = 4.3 (Table 5). Weibull statistics revealed that the process is stable and allows for the preparation of CFs with reproducible mechanical properties.…”

“…The intensity ratio (I D /I G ) of the defect band (D1 band, 1340 cm −1 ) and the graphite band (G band, 1590 cm −1 ) depends on the carbonization temperature and provides information about defects in the graphite structure. [34,[39][40][41] The lower the I D /I G ratio is, the lower the number of defects in the carbon structure is. With increasing maximum carbonization temperature, the I D /I G ratio decreased from 9.5 to 2.3 (−76%, Table 8), which is comparable to the literature known I D /I G ratio of lignin-based CFs (I D /I G = 2 to 5).…”