Enzymatic thiol-ene click reaction: an eco-friendly approach for MPEGMA-grafted modification of wool fibers

Abstract

The thiol–ene click reaction has been commonly used for the modification of many materials due to its high efficiency, high selectivity, and reliability. To further promote the sustainable technology for the modification of keratin-based materials, enzymatic biotechnology and thiol–ene click chemistry was integrated for the first time for grafting modification of wool fibers with methoxy polyethylene glycol methacrylate (MPEGMA). Wool fibers were reduced to create thiol groups and then grafted with MPEGMA through a horseradish peroxidase (HRP)-mediated thiol–ene click reaction. In order to understand the grafting mechanism of MPEGMA on wool, l-cysteine was used as a model compound for the thiol group of the reduced wool in the current research. The structures of MPEGMA reacted with l-cysteine and grafted on wool fabrics were investigated by FTIR, MALDI-TOF, Raman spectra, and XPS. The surface morphology, wettability, moisture penetrability, and regain of modified wool fibers were also assessed. The results showed that l-cysteine reacted with MPEGMA through the thiol–ene click reaction. The MPEGMA-grafted wool fabric had good surface wettability, and its moisture penetrability and regain were also improved when compared with untreated wool fabric. The HRP-initiated thiol–ene grafting reaction not only encouraged green and sustainable click chemistry but also provide an alternative eco-friendly approach for modification and functionalization of keratin and keratin-containing materials.