Preparation and Characterization of Carbon Fibers from Lyocell Precursors Grafted with Polyacrylamide via Electron-Beam Irradiation

Abstract

Carbon fibers, which act as reinforcements in many applications, are often obtained from polyacrylonitrile (PAN). However, their production is expensive and results in waste problems. Therefore, we focused on producing carbon fibers from lyocell, a cellulose-based material, and analyzed the effects of the process parameters on their mechanical properties and carbon yields. Lyocell was initially grafted with polyacrylamide (PAM) via electron-beam irradiation (EBI) and was subsequently stabilized and carbonized. Thermal analysis showed that PAM grafting increased the carbon yields to 20% at 1000 °C when compared to that of raw lyocell, which degraded completely at about 600 °C. Stabilization further increased this yield to 55%. The morphology of the produced carbon fibers was highly dependent on PAM concentration, with fibers obtained at concentrations ≤0.5 wt.% exhibiting clear, rigid, and round cross-sections with smooth surfaces, whereas fibers obtained from 2 and 4 wt.% showed peeling surfaces and attachment between individual fibers due to high viscosity of PAM. These features affected the mechanical properties of the fibers. In this study, carbon fibers of the highest tensile strength (1.39 GPa) were produced with 0.5 wt.% PAM, thereby establishing the feasibility of using EBI-induced PAM grafting on lyocell fabrics to produce high-performance carbon fibers with good yields.

Facile Fabrication of SrTiO3/In2O3 on Carbon Fibers via a Self-Assembly Strategy for Enhanced Photocatalytic Hydrogen Production

“…Figure 3b,c reveal that the SrTiO3 material layer is coated on the carbon fibers, with the diameter reduced to 6-7 µm. The reduction is probably caused by the high-temperature carbonization [17]. Figure 3b,c also show that the SrTiO3 material layer is composed of nanoparticles with a cubic phase structure, which are closely bonded to form a continuous coating layer.…”

Electromagnetic-Interference-Shielding Effectiveness of Lyocell-Based Carbon Fabrics Carbonized at Various Temperatures

“…Notably, (002) lattice diffraction peak patterns were clear. These two peaks at 24 and 43° indicate the development of the graphitic crystalline structures [ 15 , 19 , 33 , 34 , 35 , 36 , 37 , 38 ]. In Figure 1 a, with an increase in carbonization temperature to 900 °C, 1100 °C, and 1300 °C, the full width at half-maximum (FWHM) values at 2 θ values of 24° decreased to 8.09, 7.28, and 6.59°, while the intensities of these respective peaks increased.…”

“…In this study, we specifically investigated the EMl-shielding effectiveness (SE) of carbon fabrics obtained from lyocell grafted using polyacrylamide (PAM) via electron-beam irradiation (EBI). Kim et al [ 33 ] prepared carbon fiber obtained from lyocell grafted using a 100 kGy dose of EBI dose according to the PAM concentration. The results revealed a 55% carbon yield of the thermally stabilized lyocell fiber grafted with 0.5 wt.% PAM, along with high tensile strength of 1.39 GPa.…”

Electron beam irradiation treatment of textiles materials: a review

“…In 2021, Kim et al [75] initially grafted Lyocell with (PAM) via EBI followed by subsequently fabric stabilizing and carbonizing as shown in Fig. 12.…”