Biocidal acyclic halamine materials can be prepared by chlorination of amide structures grafted onto polymers such as cellulose. This approach extended available halamine structures and potential applications in medical textiles and polymers. However, the conversion yield of the amide bonds to acyclic halamine was quite low (similar to 6%) according to the grafted amide bonds. By using instrumental analyses of FTIR, NMR, and LC-MS, imidization reaction on amide bonds during the graft polymerization was identified as one of the major side reactions that could lead to the low conversion yield. Potassium persulfate was found accountable for the imidization reaction of amide structures. Potential solutions to this side reaction were proposed and evaluated as well in this study. (c) 2008 Wiley Periodicals, Inc.