Modified chitosan as antimicrobial agent and strength additive for paper products

Abstract

Chitosan is an abundant natural biopolymer with many interesting properties such as antimicrobial, biodegradable and ono-toxic qualities. The limitation of chitosan in practical applications is its poor solubility in aqueous solutio. The present research is targeted on modifying chitosan to have the water solubility and to facilitate is use as an antimicrobial agent as well as a strength additive for paper products. Two types of chitosans with low molecular weight and medium molecular weight have been modified by a cationic reagent glycidyltrimethylammonium chloride (GTMAC) under various reaction conditions. The structures of cationicmodified chitosan were characterized using FTIR and NMR. The minimum inhibitor concentrations (MIC) of the cationic chitosans against E.Coli were found at 31 and 62 ppm for the low molecular weight and the medium molecualr weight, respetively. Modified chitosan can also be used as a strength additive in conjunction with an anionic polymer for paper products. Combining cationic polymer with anionic polymer gives an improvement for tensile strength of approximately 80%