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Wool keratin, a natural biopolymer, is potentially an important renewable source of raw materials for the polyamide plastics industry. Large quantities of non-spinnable and short fibers of wool are discarded globally and hence are available as low value waste materials. In this study, we have investigated different solvents, including ionic liquids and deep eutectic mixtures, for the dissolution and processing of wool. The results show that substantial dissolution of wool (up to 475 mg wool per gram of solvent) can be obtained in the 1-allyl-3-methylimidazolium dicyanamide [AMIM][dca] ionic liquid at 130 °C. Our studies also indicated enhanced dissolution (an additional 50-100 mg g-1) of wool upon the addition of a reducing agent to the ionic liquids. Water insoluble fractions (20-40%) were obtained on the addition of water to the dissolved wool. This regenerated fraction was characterized for structural and chemical changes and found to contain a larger fraction of β-sheets and random coils than the starting material. The water soluble fraction was characterised and the results indicated the presence of fragments of low molecular weight polypeptide chains. [ABSTRACT FROM AUTHOR]

Keratin from various livestock industries is currently a waste material that has potential as a source of polyamide polymers that could replace fossil fuel derived materials if processing methods can be developed. In this work we have investigated methods for the dissolution and regeneration of keratin. Dissolution of keratin (from turkey feather) in ionic liquids was conducted under nitrogen at 130 °C for 10 hours. It was found that [BMIM]Cl, [AMIM]Cl and [choline][thioglycolate] could dissolve turkey feather keratin without addition of solvent or other chemicals. A significant percentage of solubility was obtained, up to 45% by weight. A water insoluble fraction was recovered by addition of water to the solution (∼50%). The structure and properties of this regenerated, water insoluble fraction were investigated. Compared to the starting material, the regenerated keratin shows structural changes rather than chemical changes within the polypeptide chains. The remaining fraction, consisting of water soluble fragments, was characterised by gel electrophoresis. [ABSTRACT FROM AUTHOR]