Antimicrobial Polyester Xuehong Ren, 1 Hasan B. Kocer, 2 Lei Kou, 1 S. D. Worley, 1 R. M. Broughton, 2 Y. M. Tzou, 3 T. S. Huang 3 1 Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849 2 Department of Polymer and Fiber Engineering, Auburn University, Auburn, Alabama 36849 3 Department of Nutrition and Food Science, Auburn University, Auburn, Alabama 36849 Received 10 December 2007; accepted 24 January 2008 DOI 10.1002/app.28126 Published online 13 May 2008 in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: Two N-halamine siloxane precursors, 5,5- dimethyl-3-(3 0 -triethoxysilylpropyl)hydantoin and 3-(3 0 -tri- ethoxysilylpropyl)-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]- decane-2,4-dione, have been synthesized and coated onto polyester fiber surfaces. The coated polyester was rendered biocidal after exposure to household bleach solution by converting the heterocyclic precursors to N-halamine moi- eties. The thermal properties of these coated polyester sam- ples were determined with differential scanning calorime- try. The chlorinated polyester swatches were challenged with Staphylococcus aureus (ATCC 6538) and Escherichia coli O157 : H7 (ATCC 43895) with contact times ranging from 1 to 30 min. The biocidal testing showed that the chlori- nated samples inactivated S. aureus and E. coli O157 : H7 within 5 and 30 min of contact, respectively. Standard washing tests indicated that the chlorinated coated fibers were very resistant to loss of the coating through hydro- lyses. Ó 2008 Wiley Periodicals, Inc. J Appl Polym Sci 109: 2756– 2761, 2008 Key words: biomaterials; biopolymers; functionalization of polymers; polyesters; polysiloxanes INTRODUCTION The introduction of antimicrobial activity into medi- cal textiles has been extensively studied to control the growing problem of hospital-related infections. The desirable biocidal materials should be very effective at inactivating microorganisms, as well as not toxic to humans, and environmental friendly. Techniques such as coating, grafting, and blending have been employed to impart antimicrobial func- tions onto polymers and fabrics for protection against infectious disease pathogens. Among the major biocidal materials such as qua- ternary ammonium salts, 1–3 phosphonium compounds, 4 and metal and metal salts, 5,6 the cyclic N-halamine compounds are the most promising candidates for use in manufacturing antimicrobial textiles due to their durable and regenerable properties upon expo- sure to washing cycles. The most common method to render the materials durable antibacterial activity is to produce covalent bonds between the precursor moieties and host polymers. Sun et al. have exten- sively applied the technology in making biocidal cel- lulose. 7–10 N-halamine compounds can be covalently bonded to nylon 7,11,12 by using similar methods. Another synthetic polymer, poly(ethylene terephtha- late) (PET), can also be rendered biocidal by cova- lently incorporating N-halamine moieties. 7,13 More recently in these laboratories, several reports addressed the synthesis and coating of a series of N-halamine siloxanes. These siloxanes included 3-(3 0 -triethoxysilylpropyl)-7,7,9,9-tetramethyl-1,3,8-tri- azaspiro[4.5]decane-2,4-dione (siloxane 1) (Fig. 1), (5,5- dimethyl-3-(3 0 -triethoxysilylpropyl)hydantoin (siloxane 2) (Fig. 1), 4-[3 0 -triethoxysilylpropoxyl]-2,2,6,6-tetrame- thylpiperidine, and 3-triethoxysilylpropyl-2,2,5,5-tetra- methylimidazolidin-4-one. Liang et al. have produced biocidal silica gel, 14,15 sand, 16,17 cellulose, 14,17–19 and paint 14,17 by covalently coating these N-halamine siloxanes onto the surfaces of the above materials. This study will demonstrate the creation of biocidal polyester by use of N-halamine siloxane coatings. Some ester linkages on the surfaces of polyester fibers were disassociated by treating with aqueous sodium hydroxide solution. The PET treated with NaOH was coated with 3-(3 0 -triethoxysilylpropyl)- 7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione (siloxane 1) and (5,5-dimethyl-3-(3 0 -triethoxysilylpro- pyl)hydantoin (siloxane 2) by the reaction of the resulting hydroxyl and carboxyl fragments with the siloxanes. After subsequent exposure to dilute household bleach, the PET fabrics coated with the N- halamine siloxanes will be shown to demonstrate excel- lent bicidal properties in inactivating Staphylococcus Correspondence to: S. D. Worley (worlesd@auburn.edu). Contract grant sponsor: US Air Force; contract grant number: FA8650-07-1-5908. Contract grant sponsor: HaloSource, Inc. Journal of Applied Polymer Science, Vol. 109, 2756–2761 (2008) V V C 2008 Wiley Periodicals, Inc.