BACKGROUND
Coarse low grade wool holds a share of more than 40% of the worldwide production of 1.2 million tons per year. Wool hair with a diameter above 32.5 μm and recycled wool waste represent an important source of high quality keratin. An efficient and simple shaping procedure to form all‐keratin composites could open a new approach to utilise wool keratin for production of sustainable and biodegradable all‐keratin composite.
RESULTS
In this work the dissolution and regeneration of wool keratin was studied using a concentrated solution of calcium chloride-water-ethanol as solvent and thioglycolate as reducing agent to open disulphide bonds. Up to 70% of the wool keratin dissolved in the solvent at pH 7, 60 °C. After dilution with water a share of 80% of the total keratin could be obtained as regenerated composite structure while 20% of the protein remains in solution. Based on the model studies, all‐keratin composites were prepared by impregnation of wool with solvent followed by thermal consolidation in a heated press at 60 °C and 2.2-3.3 bar pressure.
CONCLUSIONS
The new method for production of all‐keratin composites permits production of a protein‐based bio‐composite, which opens new applications for low value coarse wool and recycled wool waste. By use of cheap chemicals and thermal consolidation in standard equipment scale‐up of the technology is expected to be straightforward and commercially feasible, leading to a bio‐based and biodegradable composite material.