Characterization and Mechanism Analysis of Flexible Polyacrylonitrile-Based Carbon Nanofiber Membranes Prepared by Electrospinning

Carbon nanofiber membranes have a wide range of applications in energy and environmental fields with excellent thermal stability, electrical conductivity, and chemical resistance. Electrostatic spinning is a simple and effective technique to prepare nanofiber membranes; however, electrostatically spun carbon nanofiber membranes tend to be brittle, which is limiting the application of carbon nanofiber membranes. Herein, flexible carbon nanofiber (FCNF) membranes were prepared in this study by a simple procedure of electrostatic spinning, pre-oxidation, and carbonization. During the high-temperature carbonization process, tetra-butyl titanate (TBT) is transformed into TiO2 grains. The average diameter of FCNF rose with increasing the proportion of TBT. The stress-strain curves showed the best flexibility of FCNF-1.5. The grain size of TiO2 increased to 4.5 nm when carbonized at 1000 degrees C. TiO2 was shown to improve flexibility by relieving the stress concentration of cracks on the fiber surface, thus reducing the fracture of the produced FCNF.