Chapter 10. Fibroin Grafting Onto Wool Fibers: Recent Advances and Applications

During the process of silk manufacturing higher amounts of by-products are produced. These are mainly constituted by very short fiber wastes not useful for spinning that represent about 10% wt of spun yarn. These materials are highly homogeneous and have higher protein content (fibroin and sericin content about 94% wt), then they are suitable as source of significant amount of purified fibroin in form of powder, gel and film, useful as biopolymer for wound healing, cosmetic preparations, membranes supporting enzymes and so on. Another possible application not yet thoroughly studied can be the use of the recovered fibroin, after solubilization, as functional product for textile finishing. The aim of the present work was just to obtain bicomponent natural fibers by coating wool fibers with thin fibroin film. The finishing should be stable to washing hence much work was devoted to the search of a polyfunctional chemical reagent able to graft fibroin onto wool fibers without damaging the physical and chemical properties. To this purpose four epoxides (three bifunctional and a trifunctioctional ) were investigated. The finishing of wool with fibroin should confer to the final fabric innovative surface effects regarding shine and handfeel. Moreover, since the fibroin film should cover the scales of the wool surface responsible for felting, even an improvement of antifelting properties could be expected. The experiments were carried out on wool top as well as on fabric and the products were characterized by SEM and FTIR-ATR analyses. The better operating conditions to obtain fabrics with homogeneous fibroin coating on the wool fibers were determined.