Rechargeable N-halamine Modified Antimicrobial Latex, Epoxy, and Polyurethane Coating on Different Materials

Abstract

N-halamines are effective antimicrobial agents with good stability, rechargeability, nontoxicity and low costs. They have been applied in many fields, such as the food industry and the textile industry. The object of this study is to determine the antimicrobial activity and the antimicrobial longevity of N-halamine coated paints. Four N-halamine precursors, 1-glycidyl-s-triazine-2,4,6-trione (GTT), 1-(2,3-dihydroxypropyl)-s-triazine-2,4,6-trione (DTT), polymeric N-halamine-containing quaternary ammonium salt (PHQS) and HYDH were dissolved in three paints: latex, epoxy and polyurethane. The antimicrobial samples were challenged with Staphylococcus aureus, Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes. The antimicrobial tests illustrated that each N-halamine modified paint had different biocidal efficacy against different bacteria. However, at 5% N-halamine concentration, the modified paints were able to kill all the loading bacteria completely at 106-107 CFU/mL. Based on the results, the antimicrobial longevities and rechargeabilities of these samples were tested using iodometric/thiosulfate titration and the “sandwich test” method. The results showed that at 5% concentration level, these samples hold a 100% bacterial reduction within 30 min contact time for 21 days. These samples were able to kill all loading bacteria (106-107 CFU/mL) after 10 discharge-recharge cycle times at 5% concentration within 30 min. From this research, the N-halamine modified paints may have potential use as eco-friendly materials in food storage and food processing.