Reconstruction of Fibroin Nanofibers (FNFs) via Electrospinning: Fabrication of Poly(vinyl alcohol)/FNFs Composite Nanofibers from Aqueous Solution

Fibroin nanofibers (FNFs) achieved from physical treated silk can keep its original crystal structure, showing excellent mechanical properties, however, processing the FNFs into fibers is still a challenge. Herein, a brand-new environmentally friendly approach is proposed to manufacture FNFs-based composite nanofibers. The water-soluble polymer, poly(vinyl alcohol) PVA, was applied to increase the viscoelasticity of the spinning dope, and the content of FNFs can reach up to 20 wt%. The established phase image of spinning suggested that the concentrations ranging from 6 wt% to 8 wt% are premium to achieving relatively homogenous FNFs/PVA nanofibers. Random fibers were deposited on a fixed collector, while the fiber orientation intensity increased with the rotational speed of drum and started decreasing after 12 m/s. The mechanical properties of the composite nanofibers showed the similar tendency of variation of fiber orientation. In addition, chemical changes, crystallinity, and thermal properties of the composite nanofibers were further clarified by means of FTIR, DSC, and TG. As a result, high FNFs contained nanofibers with excellent thermal properties were created from an aqueous solution. This study is the first original work to realize the spinnability of FNFs, which provides a new insight of the FNFs.