Chitosan processing: influence of process parameters during acidic and alkaline hydrolysis and effect of the processing sequence on the resultant chitosan’s properties

The objectives of this study were to investigate the influence of reaction temperature, processing time, and mechanical shear on the depolymerization (DP) of chitosans and to evaluate the importance of the sequencing of the deacetylation and DP processes on the resultant macromolecules and their properties. Process sequence did not alter the degree of deacetylation (DD), the intrinsic viscosity, or the molecular weight (MW). Treatment conditions affected the properties of the resultant polymer: the reaction temperature and processing time had a significant impact on the MWs and DDs of the resultant polymer. Mechanical shear, however, did not significantly affect the above properties. Furthermore, polymer crystallinity was affected by reaction temperature but not by shear or processing time.