Fabrication and characterization of bio-nanocomposites based on kafirin and polyethylene oxide as auxiliary polymer: process optimization, rheological, morphological and thermal properties

The aim of this research was to compare the effects of various solvents on producing kafirin/polyethylene oxide (PEO) bio-nanocomposites by the technique of electrospinning. Different concentrations of kafirin (15, 20, 25, 30 and 40% w/v) and PEO (2, 4 and 6% w/v) were electrospun. For the dissolution and electrospinning of these two biopolymers, different solvents were used comparatively, i.e. distilled water, ethanol (70%), acetic acid (40%), 2-Butanol and glacial acetic acid. An evaluation of flow behavior showed that kafirin and PEO had Newtonian and pseudoplastic behaviors, respectively. A mixture of these two polymers demonstrated quasi-Newtonian and shear-independent behaviors in a low shear rate range, which positively affected the electrospinning process. SEM images showed that the best concentrations of kafirin and PEO were 25 and 2%, respectively, for producing nanofibers with uniform structures. Fourier-transform infrared spectroscopy (FTIR) indicated the presence of kafirin and PEO in the bio-nanocomposite after electrospinning. The FTIR proved that these two polymers had no chemical interactions with each other. Overall, the results showed that selecting an appropriate solvent and a suitable auxiliary polymer could have significant roles in producing biodegradable kafirin nanofibers. Graphical abstract