Fabrication and characterization of starch films containing chitosan nanoparticles using in situ precipitation and mechanoactivation techniques

The aim of this work is to introduce a new environmentally friendly process for the production of starch films containing submicron chitosan particles using mechanoactivated in situ precipitation in the presence of magnesium sulfate as a crosslinker. Mechanoactivation in the rotor-stator device ensures the destruction of swollen starch granules and the embedding of simultaneously formed particles in a gel structure, which prevents their aggregation. The influence of the chitosan: sulfate molar ratio (1.0 and 0.7) on the rheological and film-forming properties of dispersions was evaluated. The composite films were characterized using optical and AFM microscopy and X-ray diffraction. The tensile properties and moisture resistance of the films were also studied. An increase in the particle concentration to 10% had almost no effect on the strength of the films, but caused a 4 time increase, on average, in the elongation. The composite films were smooth, uniformly translucent, and had lower moisture absorption and water vapor permeability than the films made from starch alone. •Submicron chitosan-sulfate particles (CSP) were incorporated into starch films.•Mechanically activated CSP formation in the starch hydrogel was carried out.•CSP increase the structuring degree of starch hydrogels.•CSP increase the elongation and flexibility of starch films.•CSP-containing films had lower vapor permeability than pure starch films.