Controlled de-cross-linking and disentanglement of feather keratin for fiber preparation via a novel process

Pure protein fibers were fabricated from chicken feathers via a potentially green process. In the last several decades, efforts have been made to produce keratin-based industrial products, especially fibers. However, the methods of producing keratin fibers directly from chicken feathers could not be repeated. In this research, protein fibers from chicken feathers were developed using chemicals that could be either derived from renewable resources or facilely recycled. Backbones of keratin were preserved after cleavage of disulfide bonds using cysteine. Sodium dodecyl sulfate (SDS) was applied to dissolve keratin for spinning. Increasing SDS concentration intensified the ordered conformation of keratin, first increased and then decreased the viscosity of solution, suggesting continuous disentanglement of keratin molecules and enhancement in inter- and intramolecular electrical repulsion. Diameters of the obtained fibers as small as 20 μm also proved good drawability of the keratin solution. Change in crystallinity indices was found to be consistent with that of tensile properties of the keratin fibers. In summary, regenerated fibers were successfully produced as linear keratin with preserved backbones that could be untangled and aligned in a controlled manner.