Anna Wojtasz-Pająk and Piotr J. Bykowski
Sea Fisheries Institute, Kołłątaja 1, 81-332 Gdynia, Poland

Key words: chitin, deacetylation, chitosan.

Abstract.
The properties of chitosan: deacetylation degree, molecular weight and viscosity of its solution are most often modified by choosing the time and temperature of the reaction of deacetylation of chitin. The relationships between the time and temperature of the reaction of deacetylation and the discussed parameters are described by general equations presented in the paper. The polymer was obtained from shells of common shrimp(Crangon crangon [L.]). Deacetylation was conducted by using a 50% solution of sodium hydroxide. Temperature and time of the deacetylation reaction were calculated from general equations. The properties characterizing the produced chitosans remained within the specified ranges. By using the derived equations for the computation of the time and temperature of the reaction of deacetylation, chitosan with desired properties can be produced. Deviations of the values of the deacetylation degree, average viscometric modecular weight and viscosity of the solution characterizing the product from the values computed for a given time-temperature variant depend on the fluctuations of the temperature of the process.