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 TiO 2 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 TiO 2 increased to 4.5 nm when carbonized at 1000 °C. TiO 2 was shown to improve flexibility by relieving the stress concentration of cracks on the fiber surface, thus reducing the fracture of the produced FCNF.