Chemical Modification of Commercial Fabrics by Photoinduced Grafting Tannic Acid to Produce Antioxidant and Antibacterial Textiles

The goal of this study was to provide antioxidant and antibacterial properties to different types of fabrics via tannic acid (TA) covalent grafting. To that extent, TA was first methacrylated using glycidylmethacrylate. TA derivatives were characterized using infrared spectroscopy and 1H NMR to assess the degree of acrylation. Antioxidant and antibacterial properties of TA were preserved after chemical modification. The coating process was studied using infrared spectroscopy (IR), weight gain, and radical scavenging activity (RSA) measurements. To covalently bond TA to raw polypropylene (PP) and PP coated with chitosan, photoinduced grafting was performed. The process was optimized and resulted in fabrics with enough tannic acid to provide strong antioxidant activity, with RSA ranging at 95%. The antibacterial activity was assessed against E. coli and S. aureus, the main strains responsible for nosocomial infections. Results revealed a substantial reduction of bacterial contamination for PP samples coated with chitosan, with stronger activity against E. coli, attributed to hydrophobic repellence. This study highlights the benefits of using tannic acid to obtain antioxidant and antibacterial fabrics.