where [η] is intrinsic viscosity, k and α are constants, and Mv is viscosity
average molecular weight. The values of k and α depend on the
polymer type, solvent, and temperature. The intrinsic viscosity of
CTS was measured with an Ubbelohde viscometer in 2% acetic acid/
0.2 M sodium acetate, the values of the constants are 1.38∗10−4
and 0.85, respectively, at 25 °C as reported in Ref. [28] and they do
not depend on the deacetylation degree of CTS. Molecular weight of
chitosan determined by this method was 4.38∗107 g/mol.