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.