Browsing by Subject "Electrospun Nanofibers"

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    Fabrication of Submicron Thermosetting Carbon Nanotube-Epoxy Fibers Using Electrospinning
    (American Society for Composites, 2020-09-20) Aliahmad, Nojan; Wable, Vidya; Biswas, Pias Kumar; Hernadez, Iran; Dalir, Hamid; Agarwal, Mangilal
    Recently epoxy-based nanocomposites are gaining tremendous attention in many structural applications such as those in aerospace, automotive and motorsports. This research represents a new approach to fabricate submicron thermoset epoxy filaments enhanced with carbon nanotubes (CNT), through optimized curing followed by an electrospinning process. The optimized curing process is based on the uniform mixing of CNT with epoxy, and partial curing of the CNT/epoxy mixture with the hardener through a thermal treatment without adding any plasticizers or thermoplastic binders. Later the fibers have been made by electrospinning of the semi-cured mixture. Fig 1 shows the fabrication process of the described filaments. The key goal is to make the thermosetting epoxy without adding any thermoplastic to keep the integrity and quality of the fibers. The diameters of these filaments can be tuned between 100 nm to 500nm. Further, the CNT structure has been aligned inside the filament structure by the presence of the electrostatic field during the electrospinning process results in better stability and smaller diameters for the fibers. The fabricated filaments show that adding a low amount of CNT in the epoxy structure, better structural, electrical and thermal stability, has been achieved.
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    Multi-nozzle electrospinning optimization of carbon nanotube/epoxy submicron filaments – A numerical study
    (American Chemical Society, 2021-08-26) Liyanage, Asel Habarakada; Biswas, Pias Kumar; Cumbo, Eric; Siegel, Amanda P.; Agarwal, Mangilal; Dalir, Hamid
    Electrospinning is the process of spinning a polymer melt or solution through a nozzle in the presence of a high-voltage electric field, which causes it to coalesce into a continuous filament. Diameter of the filament is anywhere from tens of nanometers to a few microns, depending on the materials being spun, viscosity, electric field, and other experimental conditions. This process has gained attention because of its versatility, low cost, and ease of processing for many polymers. Thermosetting reinforced epoxy is particularly challenging because of the variability in viscosity caused by temperature changes and induced by the electrospinning process itself. Nevertheless, our research group previously developed the fabrication and characterization of submicron carbon nanotube (CNT)–epoxy nanocomposite filaments through an electrospinning process via a single nozzle, horizontal spray process. In this study, electric fields and other parameters were simulated using COMSOL Multiphysics® software to understand the induced surface charges that cause the Taylor cone of the CNT-epoxy solution.. Optimization of the simulation results coupled with those of experiments enabled us to achieve stability and fabricate smaller but more uniform diameter fibers with enhanced structural, electrical, and thermal properties. The main challenge addressed in this paper is the use of the COMSOL models to understand the effect of different geometries on the electric field in the presence of multi-nozzle systems.