A controlled, highly effective and sustainable approach to the surface performance improvement of wool fibers

Abstract

As part of the green concept, biorenewable deep eutectic solvent has emerged as an appealing type of ionic liquid and has shown their advance as environmentally benign sustainable alternative to the conventional solvents in the deep utilization of natural polymers, such as cellulose and lignin, which contributes to alleviating the pressure of the reduction of non-renewable resource. However, it has been few studies related to the value increase of another abundant natural polymer-protein material.As a representative, keratin fiber is a renewable biopolymer with excellent biocompatibility and biodegradability, but the poor surface performance results it is difficult to be functional modified, and the application is also limited in the textile industry. In this paper, the dissolution was controlled on the wool fiber surface using an eco-friendly and biorenewable deep eutectic solvent (DES). Surface dissolution is different from those used in previous studies and has been investigated in detail for the first time. The results show that a fast and facile surface dissolution process could be reached by incubating the wool fiber in DES for 10 min and the DES can be reused more than 10 times. Allwörden reaction, SEM and AFM images show that the controlled dissolution on the fiber surface was successfully accomplished. This process was also accompanied by the dissolution of amino acids and cleavage of disulfide bonds, which were ascertained using Raman spectroscopy, XPS and amino acid analysis. The protein macromolecular backbone and secondary structure of the surface-dissolved wool were not lost using FTIR spectroscopy, XRD and NMR spectroscopy. The modified wool by DES method has better surface properties; moreover, the method offers a more cost-effective and sustainable alternative for the modification of protein material.