Influence of methacrylamide grafting on silk fabric properties

In this study, methacrylamide (MAAm) was employed as the grafting monomer, and silk fabrics were modified by free radical polymerization using a potassium persulfate–sodium bisulfite redox initiation system. Grafted silk fabrics with different weight gains were prepared, and the effects of MAAm grafting on wrinkle recovery, moisture regain, water vapor permeability, air permeability, tensile properties, antibacterial activity, abrasion resistance, and washing durability were systematically evaluated. Results show that with increasing graft weight gain, the crease recovery angle and moisture absorption improved, whereas air permeability decreased markedly. At lower grafting levels, the increase in tensile strength per unit width exceeded the increase in fabric areal density. However, at higher grafting levels, the strength increment became smaller relative to the density increase. Grafting also substantially reduced elongation. At 33.20% graft weight gain, compared with ungrafted silk, the dry crease recovery angle increased by 14.0%, moisture regain by 24.0%, and water vapor transmission by 4.8%; in contrast, air permeability decreased by 58.0% and elongation by 32.7%. Antibacterial activity against S. aureus was slightly enhanced, whereas activity against E. coli declined. In addition, grafting had a pronounced negative effect on initial abrasion resistance but improved long-term wear resistance. Collectively, this study comprehensively discusses the advantages and disadvantages of MAAm grafted silk fabrics from different perspectives, and reveals the relevant mechanisms of their impact on performance, filling a gap in research on the influence of MAAm grafted silk fabrics on their performance. It also offers a useful reference for producers and consumers in the manufacture and selection of grafted silk products.