Oxidative stabilization of polyacrylonitrile nanofibers and carbon nanofibers containing graphene oxide (GO): a spectroscopic and electrochemical study

In this study, a precursor for carbon nanofibers (CNF) was fabricated via electrospinning and carbonized through a thermal process. Before carbonization, oxidative stabilization should be applied, and the oxidation mechanism also plays an important role during carbonization. Thus, the understanding of the oxidation mechanism is an essential part of the production of CNF. The oxidation process of polyacrylonitrile was studied and nanofiber webs containing graphene oxide (GO) are obtained to improve the electrochemical properties of CNF. Structural and morphological characterizations of the webs are carried out by using attenuated total reflectance Fourier transform infrared spectroscopy and Raman spectroscopy, scanning electron microscopy, atomic force microscopy and transmission electron microscopy. Mechanical tests are performed with a dynamic mechanical analyzer, and thermal studies are conducted by using thermogravimetric analysis. Electrochemical impedance spectroscopy, and cyclic voltammetry are used to investigate capacitive behavior of the products. The proposed equivalent circuit model was consistent with charge-transfer processes taking place at interior pores filled with electrolyte

Electrospun carbon nanofiber web electrode: Supercapacitor behavior in various electrolytes

Carbon nanofibers (CNFs) draw great interest due to their noticeable mechanical, electrochemical, and physical properties. In this study, polyacrylonitrile-based CNFs are obtained via electrospinning technique. Thermal oxidation and low temperature (950 degrees C) carbonization are applied to the electrospun web in order to achieve CNF. Through the process, Fourier transform infrared-attenuated total reflectance spectroscopy and Raman spectroscopic results are investigated. The electrochemical properties of the self-standing CNF webs are examined with electrochemical impedance spectroscopy and cyclic voltammetry. In addition, various electrolyte solutions are studied to investigate the capacitive behavior of CNF webs. Electrolyte type variation has a significant effect on the capacitance results and high capacitance values are achieved in aqueous solution. According to the differing electrolyte types, specific capacitance values (C-sp) are recorded between 204 and 149 Fg(-1) where maximum specific capacitance is obtained in 0.5 M H2SO4 as 204 Fg(-1). (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45723

Fabrication of gelatin nanofiber webs via centrifugal spinning for N95 respiratory filters

Due to the impact of the Covid-19 pandemic, the usage of numerous protective face masks has faced an explosion in demand around the world. Therefore, the need to reduce the environmental pollution caused by disposable single-use face masks has become vital. Recently, alternative raw material solutions have been discussed to eliminate the consumption of single-use plastics. Within this research, gelatin nanofibers were fabricated via centrifugal spinning technique, and filtration media were investigated in terms of air permeability and filtration efficiency. In addition, morphological properties were examined with scanning electron microscopy. Fabricated fibers have a changing average diameter range from 232 to 778 nm, and targeted 95% filtration efficiency was achieved in several compositions. It was proven that biodegradable gelatin nanofibers could be a sustainable alternative for disposable N95 respiratory filters.This research was funded by The Scientific and Technological Research Council of Turkey (TUBITAK) (TEYDEB-1507), Project number 7200424. We would like to thank Halavet Gelatin, Turkey, for their gelatin supply.Scientific and Technological Research Council of Turkey (TUBITAK) [TEYDEB-1507, 7200424