Preparation and characterization of surface active N-butyrated low molecular weight chitosan

Abstract

New classes of natural surfactants have been prepared through the reaction of low molecular weight chitosans (1.3, 6, 10, 18 and 30 kDa) with butyric anhydride in aqueous medium. The new compounds were characterized by ¹H NMR and FT-IR spectroscopy. Their surface tension and particle size were also determined. The degree of substitutions was in the range of 44-57% as confirmed by ¹H NMR spectra. These compounds possess low aggregate size 12-18 nm with higher surface activity on comparison with native chitosan. The prepared compounds are found to be soluble in all pH media in contrast to native chitosan. This may be due to the breaking up of chitosans inter-strand hydrogen bonding upon substitutes.