Antibacterial Activity of Cationically Modified Cotton Fabric with Carboxymethyl Chitosan Amira M. El-Shafei, 1 Moustafa M.G. Fouda, 1 Dierk Knittel, 2 Eckhard Schollmeyer 2 1 Textile Research Division, National Research Centre, Dokki, Cairo, Egypt 2 German Textile Research Centre, D-47798 Krefeld, Germany Received 25 June 2007; accepted 21 January 2008 DOI 10.1002/app.28352 Published online 16 July 2008 in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: A water-soluble carboxymethyl chitosan was prepared with a view to develop a multifunctional finish on cotton. Carboxymethyl chitosan (CMCTS) was synthesized by chemical reaction of chitosan with mono- chloroacetic acid under alkaline condition. The water soluble CMCTS was applied to cationized cotton with different concentrations. The treated fabrics were charac- terized through monitoring the textile physical proper- ties and for the antibacterial activity against Escherichia coli DSMZ 498 and Micrococcus luteus ATCC 9341. The results obtained show that the physical properties of the treated fabrics are improved by increasing the CMCTS concentration, as well as the antibacterial activity. Ó 2008 Wiley Periodicals, Inc. J Appl Polym Sci 110: 1289–1296, 2008 Key words: cationized cotton; carboxymethyl chitosan; textile finishing; antibacterial activity, polyelectrolyte INTRODUCTION Chitosan is the deacetylated derivative of chitin, which is the second most abundant polysaccharide found on earth next to cellulose. Chitin, a major component of the shell of crab and shrimp, is one of the most abundant natural polysaccharides with a large unexplored commercial potential. Chitosan is found in some fungi, but its quantity is so limited that it is mainly produced commercially by alkaline deacetylation of chitin. 1 Chitosan is a partially deace- tylated polymer of acetyl glucosamine obtained after alkaline deacetylation of chitin. It comprises copoly- mers of glucosamine and N-acetyl glucosamine 2 and has a combination of many unique properties such as nontoxicity, biocompatibility, and biodegradabil- ity. 3 Chitosan has got wide application in textile dye- ing and finishing as a substitute for the various chemicals used in textile processing. 4 It has been used as a pretreatment agent in dyeing of cotton, in textile printing, wool dyeing, and shrink proofing, and in durable press finish. However, the applica- tion of chitosan in textiles is limited due to its poor solubility above pH 6.5. 5 Another major problem is its poor durability on cotton textile due to lack of strong bonding forces between the two polysaccha- rides. 6 It was hypothesized that if a water-soluble chitosan derivative could be developed it can lead to development of a multifunctional finish. Cotton can be made antimicrobial, its dyeability can be modified or enhanced and treatment with chitosan can also impart wrinkle recovery property to it, and because of this water-soluble carboxymethyl chitosan (CMCTS) was prepared. The carboxymethyl derivatives N,O-substituted derivatives are water soluble and contain an amino group either as the primary (ÀÀNH 2 ) or as secondary amine (ÀÀNHÀÀCH 2 COOH). 7 The degree of water solubility of this derivative N- and O-substituted appears to vary with the molecular weight of the material as well as the degree of substitution. The multifunctional chitosan derivative will be favorable to find new kind of polysaccharide with multifunc- tion such as antibacterial character. 8 The textile industries continue to look for eco- friendly processes that substitute for toxic textile chemicals. In this point of view, chitosan and car- boxymethyl chitosan are selected to be useful as excellent candidates for an ecofriendly textile chemi- cal. 4 The major problem of chitosan as antibacterial agent is the loss of cationic nature and antibacterial activity under alkaline condition and due to this, carboxymethyl chitosan can afford a suitable water- soluble substitute derivative that can work properly under alkaline condition. This work is undertaken with a view of imparting cotton fabric with antibacterial activity. The fabric Correspondence to: A. M. El-Shafei (mayamira2001@ yahoo.com). Contract grant sponsor: Federal Ministry for Education and Research (BMBF); contract grant numbers: 033459, 0312689C. Contract grant sponsor: Deutsche Forschungsgemein- schaft (DFG); contract grant number: 445 AGY-112/37/04. Journal of Applied Polymer Science, Vol. 110, 1289–1296 (2008) V V C 2008 Wiley Periodicals, Inc.