Preparation and mechanical properties of melt-spun carbon fibers from wood tar and wood tar/kraft lignin blends

초록

The chemical and mechanical properties of the wood tar (WT) preheated at 80°G for a period time were investigated as a suitable precursor of melt-spun carbon fibers using gel permeation chromatography (GPC), elemental analyzer, hydroxyl content analysis and thermogravimetric analyses (TGA). As the results, the WT24 (heat-treated at 80°C for 24 h) was selected as a precursor for making carbon fiber. The micro-size spun fibers were prepared from the WT24 and WT24/kraft lignin (KL) blends (95/5-70/30, w/w) using melt-spinning. The carbon fibers were then prepared by stabilizing melt-spun fibers in the temperature range of 50-250°C and followed by carbonizing thermal-stabilized fibers at 1,200°C without holding time under N₂ gas flow. The diameters of carbon fibers produced from both WT24 and WT24/KL averaged 129.5 ±16.6 μm, and their surfaces were smooth. However, it was seen that the holes in carbon fiber cross sections were often observed as the KL content increased, confirmed by scanning electron microscopy (SEM) analysis. The tensile strength of WT24 carbon fiber was measured as 129.9±32.6 MPa, while tensile strength of carbon fibers produced from WT24/KL blends decreased from 117.8±41.0 to 24.7±9.5 MPa as the KL content increased.

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