Carbon fiber based composites have been recognized as optimal materials for advanced engineering application. Due to their unique reinforcing abilities, combined with high strength, low mass, and excellent fatigue resistance, carbon fiber-reinforced composites outperform metallic material such as aluminum and titanium alloys [1]. In the realm of carbon fibers, petrochemical-based poly(acrylonitrile) (PAN) is by far the most important precursor. However, there are several disadvantages associated with the use of PAN, such as high cost, slow carbonization, and environmental problems associated to the high carbon footprints and solvent usage during its production through wet-spinning [2]. In order to address these issues, recent efforts have been directed towards the use of renewable resources as well as finding alternative ways of fabricating sustainable composites without using toxic and harmful solvents. In the quest for alternative sources, lignin and cellulose have gained increased attention due to their wide availability in substantial amounts. Within this topic, we have investigated the blending of lignin and cellulose esters to produce carbon fibers in a green and renewable way, without any use of chemical solvent. Carbon fiber precursor were prepared from lignin derivatives, blended in various concentration with cellulose acetate and an appropriate plasticizer in order to improve the processability by favoring thermo-plasticization and softening during the spinning of the fibers. In detail, the fibers were prepared with the melt-spinning technique employing a micro-extruder, avoiding the use of solvents as in the case of PAN. The glass transition and degradation temperatures of the extruded materials were assessed by a differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. Subsequently, the fibers were subjected to heat treatments under air by means of a TGA, simulating the stabilization and oxidation process of the precursor fibers. Preliminary results highlighted that the stabilization tests carried out at lower temperatures lead to less degradation of the sample with the consequent possibility of stabilizing the fibers while preserving their shape.
Stabilization of Carbon Fibers from Lignin and Cellulose Precursors
Benedetta Palucci;Adriano Vignali;Fabio Bertini
2022
Abstract
Carbon fiber based composites have been recognized as optimal materials for advanced engineering application. Due to their unique reinforcing abilities, combined with high strength, low mass, and excellent fatigue resistance, carbon fiber-reinforced composites outperform metallic material such as aluminum and titanium alloys [1]. In the realm of carbon fibers, petrochemical-based poly(acrylonitrile) (PAN) is by far the most important precursor. However, there are several disadvantages associated with the use of PAN, such as high cost, slow carbonization, and environmental problems associated to the high carbon footprints and solvent usage during its production through wet-spinning [2]. In order to address these issues, recent efforts have been directed towards the use of renewable resources as well as finding alternative ways of fabricating sustainable composites without using toxic and harmful solvents. In the quest for alternative sources, lignin and cellulose have gained increased attention due to their wide availability in substantial amounts. Within this topic, we have investigated the blending of lignin and cellulose esters to produce carbon fibers in a green and renewable way, without any use of chemical solvent. Carbon fiber precursor were prepared from lignin derivatives, blended in various concentration with cellulose acetate and an appropriate plasticizer in order to improve the processability by favoring thermo-plasticization and softening during the spinning of the fibers. In detail, the fibers were prepared with the melt-spinning technique employing a micro-extruder, avoiding the use of solvents as in the case of PAN. The glass transition and degradation temperatures of the extruded materials were assessed by a differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), respectively. Subsequently, the fibers were subjected to heat treatments under air by means of a TGA, simulating the stabilization and oxidation process of the precursor fibers. Preliminary results highlighted that the stabilization tests carried out at lower temperatures lead to less degradation of the sample with the consequent possibility of stabilizing the fibers while preserving their shape.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
