Preparation and application of durable flame retardant antimicrobial finishing agent for cotton fabrics

Abstract Simultaneously endowing cotton fabrics with flame retardancy and antimicrobial functionality is a key research focus. This study synthesized a finishing agent, FRA-PHMG, using glycidyl methacrylate, polyhexamethylene guanidine hydrochloride, phosphoric acid, and urea as primary raw materials. Cotton fabric modifieded with a 200 g/L FRA-PHMG solution and cured at 180°C for 3 minutes exhibited effective flame retardancy, achieving a LOI of 42.1% and a char length of 4.3 cm with no afterflame observed. The modification significantly suppressed heat release, reducing the total heat release by 48.50% and the peak heat release rate by 91.40% compared with the control fabric. Furthermore, the modified cotton demonstrated outstanding antimicrobial activity, achieving 99% against Escherichia coli , 99% against Staphylococcus aureus , and 100% against Candida albicans . The fabric also displayed excellent washing durability, maintaining a limiting oxygen index of 31.6%, a char length of 7.0 cm, and antimicrobial inhibition rates above 85% after 50 laundering cycles, with no detectable leaching of agents, due to robust covalent bonding with the cellulose. The finishing process had a minimal impact on the tensile properties of the fabric.