FABRICATION OF CARBON FIBER LIGNIN BASED EXTRACTED FROM BLACK LIQUOR WASTE

• Main Author: Mar'atus Shoimah, Silvia
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/46401
• Institution: Institut Teknologi Bandung

Carbon fiber is a type of high-performance fiber which can be applied in various fields. Carbon fiber has the highest price compared to other fibers. The price of carbon fiber is strongly influenced by the production cost, especially the manufacturing cost of the carbon fiber precursor. Precursor is a raw material required to produce carbon fiber which contributes around 51% of the total manufacturing cost of carbon fiber. Lignin is the second most abundant natural polymer in the world and has the potential to be utilized as carbon fiber precursor due to its high amount of carbon content, which reached 68%. In this research, carbon fiber is fabricated from lignin-based fiber precursor extracted from black liquor waste. Lignin was extracted from black liquor waste by using the acidification method until pH 2 and followed by washing the lignin by using the deionized water (DI). The lignin was refluxed by using DI water with water to lignin ratio of 100, 150, 200, 300, and 400 (w/w). Lignin was blended with polyvinyl alcohol (PVA) with the concentration of 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% (wt%) and formed into fiber by using the wet spinning method. The stabilization process was carried out at 220ºC and followed by carbonization process at 850ºC in nitrogen atmosphere. The tensile strength of precursor and carbon fiber was determined according to ASTM D-3882 standard. SEM characterization was conducted to evaluate the morphology of lignin fiber. DSC/TGA characterization was conducted to evaluated the thermal properties, miscibility, and carbon yield of the lignin fiber, respectively. Based on the purity test, the highest purity of lignin was obtained in LR300 sample with a purity of 95.91%. The highest tensile strength of lignin fiber precursor is 2.8 GPa for 40% lignin/PVA (L60P40). The result obtained in this research showed that the lignin fiber has a potential to be utilized as carbon fiber precursor. However, the strength and stiffness of lignin-based carbon fiber was still lower than commercial carbon fiber. The highest strength and stiffness of carbon fiber were observed in L70P30 precursor, with a tensile strength of 528.92 MPa and stiffness of 40.61 GPa.