Abstract:

To promote the recycling of waste wool, keratin was extracted from the waste wool using L-cysteine as reducing agent, and spinning solution was prepared by dissolving the regenerated keratin in the sodium carbonate-sodium bicarbonate buffer. Multi-walled carbon nanotubes were functionalized with 4-substituted benzoic acid by direct Friedel-Crafts acylation. Regenerated keratin/functionalized multi-walled carbon nanotubes  (F-MWCNTs) composite fibers were wet-spun from the mixed solution of F-MWCNTs suspensing and keratin solution. The results show that F-MWCNTs were homogeneously dispersed in keratin matrix without any aggregation.  With the addition of F-MWCNTs, the composite fibers present crystallinity and content of β-sheet gerater than pure keratin fibers. The low addition of F-MWCNTs enhanced the mechanical properties of composite fibers, and the highest breaking stress of the composite fibers reaches 91.5±12.6 MPa with 0.15% F-MWCNTs, which is improved by 139% in comparison with that of pure keratin fibers.

Key words: wool keratin, protein fiber, multi-walled carbon nanotube, Friedel-Crafts acylation, wet spinning