Synthesis and property studies of N‐carboxymethyl chitosan

N‐carboxymethyl chitosans (N‐CMC) were synthesized from chitosan in water with chloroacetic acid instead of comparatively expensive glyoxylic acid. The optimal reaction conditions were 90°C and 4 h with a ratio of chloroacetic acid to chitosan 5 : 1(w/w). The degree of substitution of product exceeded 1.32. The N‐carboxymethyl chitosans were characterized by XRD, FTIR, ¹H‐NMR, and the water solubility and isoelectric point of N‐CMC with different degrees of substitution were determined. FTIR and ¹H‐NMR data has confirmed that the substitution reaction occurred on the amino groups. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011