Preparation and Characterization of Nano Chitosan from Crab Shell Waste by Beads-milling Method

This research aimed to produce well-dispersed chitosan nanoparticles suspension from a crab shell waste by beads-milling method. Tween 80 surfactant was applied as a dispersing agent to improve the dispersion stability. A mono-dispersed chitosan nanoparticle suspension was obtained at milling times 90 and 120 minutes by adjusting their pH values. The characterization was performed to obtain the size and size distribution, the particle stability, the characteristics of the functional groups and the degree of deacetylation. The results showed that chitosan nanoparticle was achieved in the milling process 90 minutes and low pH dispersion medium. The average particle size of the as-prepared suspension is 232.5 nm with polydispersity index of 0.452. Beads milling process did not change the glucosamine and N-acetylglucosamine content on chitosan structure indicated by degree of deacetylation higher than 70%. Based on the FTIR investigation the mechanism of surface modification of chitosan due to milling process was proposed. It was concluded that beads milling process can be applied to prepare chitosan nanoparticles by proper adjustment of the milling time, pH and appropriate dispersing agent type and amount. (paper)