Preparation of low-cost carbon fiber precursors from blends of wheat straw lignin and commercia textile-grade polyacrylonitrile (PAN)

Low-cost precursor fibers (PFs) were prepared from blends of a wheat straw lignin (WSL) and a commercial textile-grade polyacrylonitrile (PAN) by wet spinning, and then the precursors were converted into carbon fibers (CFs) by thermal stabilization and carbonization. The PFs were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The lignin content in the blends was found to play an important role in the PF structure, which was closely related to the change of intermolecular forces in the spinning solution. The lignin, acting as the carboxylic acid comonomer, had significantly promoted the thermal stabilization of the lignin/PAN blend PFs, which helped to further decrease the production cost of CFs. With increasing lignin contents, the carbon content of CFs remained at about 95%. The carbon of lignin could be utilized for the preparation of CFs.