Reinforced Wool Keratin Fibers via Dithiol Chain Re‐bonding

Abstract

Regenerated wool keratin fibers (RWKFs) have heretofore attracted tremendous interest according to environmental friendliness, ample resource, and intrinsic biocompatibility for broad applications. In this realm, both uncontrollable keratin fibril assembly procedure and resultant insufficient mechanical strength, have greatly hindered their large-scale manufacture and commercial viability. Herein, a continuous wet-spinning strategy is put forward to rebuild wool keratin into compact regenerated bio-fibers with improved strength via disulfide re-bonding. Dithiothreitol (DTT) has been introduced to renovate disulfide linkage inside keratin polypeptide chains, and bridge keratin fibrils via covalent thiol bonding to form a continuous backbone as mechanical support. A thus-derived RWKF manifests a tensile strength of 186.1 ± 7.0 MPa and Young's modulus of 7.4 ± 0.2 GPa, which exceeds those of natural wool, feathers, and regenerated wool or feather keratin fibers. The detailed wetspinning technical parameters, such as coagulation, oxidation, and posttreatment, have been systematically optimized to guarantee the continuous preparation of high-strength regenerated keratin fibers. This work offers insight into solving the concurrent challenges for continuous manufacture of regenerated protein fibers and sustainability concerns about biomass waste.

Upcycling of Keratin Wastes in Sustainable Textile Fiber Applications

“…However, the cost-intensive nature of DTT and its substantial consumption at 13 wt % rendered it impractical for extensive large-scale manufacturing endeavors. 13 In this work, we did not succeed in spinning a pure regenerated wool fiber. The filaments spun from pure keratin solutions were too weak to withstand the elongational stress in the air gap.…”

“…This method yielded keratin fibers exhibiting a remarkable tensile strength of 180 MPa. However, the cost-intensive nature of DTT and its substantial consumption at 13 wt % rendered it impractical for extensive large-scale manufacturing endeavors . In this work, we did not succeed in spinning a pure regenerated wool fiber.…”

“…The disulfide bonds can be disrupted via oxidation or reduction using peroxides, sulfites, and thiols, , while the hydrogen bonds and ionic bonds are disrupted by urea and SDS, respectively . An aqueous solution containing different amounts of urea, SDS, and disulfide bond cleavage agent is commonly used for the extraction of keratin. ,, This method requires an alkaline condition (pH > 10), and therefore, a significant amount of strong bases and, subsequently, a large amount of strong acids to neutralize the hydrolysate are needed …”

“…11 An aqueous solution containing different amounts of urea, SDS, and disulfide bond cleavage agent is commonly used for the extraction of keratin. 10,12,13 This method requires an alkaline condition (pH > 10), and therefore, a significant amount of strong bases and, subsequently, a large amount of strong acids to neutralize the hydrolysate are needed. 14 Ionic liquids (ILs) are solvents that have shown promise for the dissolution of keratin.…”

Scalable Fabrication of Fabrics Dyed with Wool Powder and Its Deodorization Performance

“…21 These three peaks are attributed to the characteristic functional groups of protein, which correspond to Amide A, Amide I, and Amide II, respectively. 22 For pristine cotton fabric, absorption bands centered at 3335 and 3291 cm 26 Both the coated cotton fabrics and polyester fabrics displayed characteristic peaks of wool powder (Figure 2c), including Amide I and Amide II, manifesting that the wool powder was successfully coated on fabrics. Moreover, the peak intensity of Amide I and Amide II observed on fabrics increased gradually as increasing the mass ratio of wool powder in the paste.…”