Electrospun Thermosetting Carbon Nanotube–Epoxy Nanofibers

This paper represents the process of fabrication and characterization of submicron carbon nanotube (CNT)–epoxy nanocomposite filaments through an electrospinning process. Electrospinning is one of the most versatile, inexpensive, and environmentally well-known techniques for producing continuous fibers from submicron diameter all the way to tens of nanometer diameter. Here, electrospinning of submicron epoxy filaments was made possible by partial curing of the epoxy by mixing the hardener and through a thermal treatment process without the need for adding any plasticizers or thermoplastic binders. This semicuring approach makes the epoxy solution viscous enough for the electrospinning process, that is, without any solidification or nonuniformity caused by the presence of the hardener inside the mixture. The filaments were spun using a CNT/epoxy solution with a viscosity of 65 p using 16 kV and a collector distance of 10 cm. The diameter of these filaments can be tuned as low as 100 nm with adjustment of electrospinning parameters. By incorporating a low amount of CNT into epoxy, better structural, electrical, and thermal stabilities were achieved. The CNT fibers have been aligned inside the epoxy filaments because of the presence of the electrostatic field during the electrospinning process. The modulus of the epoxy and CNT/epoxy filaments were found to be 3.24 and 4.84 GPa, respectively. The presence of the CNT can lead up to 49% improvement on modulus. Accordingly, using a commercially available epoxy suitable for industrial composite productions makes the developed filament suitable for many applications.