An N-Halamine biocidal polymer was prepared by co-polymerizing toluene-2,6-diisocyanate with a new heterocyclic uramil-based azo-monomer, followed by halogenation. The mode of action of N-halamine polymers on bacteria was investigated and halogenation conditions (temperature, halogenation time, halogen concentration) were optimized for bactericidal action against E. coli and S. aureus. It was found that the mode of action of this type of polymer is a combination of different factors; contact, release, and through interaction of the polymer with the bacterial medium. The most effective halogenation conditions were stirring 1 g polymer in 10 mL sodium hypochlorite (10 %) for 1 h at ambient temperature (22 degrees C). (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 2404-2412, 2009