Preparation of chitosan powder and investigation of its properties

For the preparation of chitosan powder, the thermocatalytic destruction method developed in our earlier works was applied. Chitosan samples obtained from exoskeletons of crustaceans with a molecular weight of 500 kDalton, deacetylation degree 80% and with a molecular weight of 900 kDalton, deacetylation degree 70% were investigated. For these samples, optimal thermocatalytic treatment conditions for partial destruction of chitosan, which was controlled from the change in intrinsic viscos ity, to the levelling-off degree of polymerization (LODP) were developed. In our case, LODP was ~ 140 units. The destructed chitosan was dissolved in water and precipitated with adding a definite amount of NaOH. The precipitated chitosan was washed off, dried at 60 °C, and ground in a ball mill. As a result, a cream-like powder was obtained, whose major part of particles had sizes of 1-15 µm. The properties of the obtained powder were investigated by the microscopic, X-ray diffraction, IR spectroscopic, and physico- chemical methods.