ABSTRACT
The effect of composition and mechanoactivation in the rotor-stator device on the rheological and film-forming properties of casting blends based on corn starch and chitosans with high (HDC) and low (LDC) deacetylation degree was studied. Films were characterized using optical and atomic force microscopy, X-ray diffraction, FTIR-spectroscopy and by tensile and moisture permeability testing data. An increase in chitosan content was found to result in the blends viscosity increase as well as the tensile strength, elongation and moisture permeability of films. Mechanoactivation was shown to cause an increase in the homogeneity, smoothness and transparency of the films, and an increase in the tensile strength by 1.5 and 2.5 times for the HDC and LDC based films, respectively. It is concluded that the developed eco-friendly and easily implemented method, which allows improving the unsatisfactory properties of starch-chitosan films without the introduction of additional chemicals, can be used on an industrial scale.
ABSTRACT
The method of mechanical activation in the rotor-stator device was used to combine the starch hydrogel and the latex of the synthetic copolymer. The compatibility of the components was found to improve consistently by the preliminary mechanoactivation of the starch gel and the joint activation of the mixturs. The joint activation was shown to promote the crystallization of starch and the amorphous phase ordering of the composite. An increase in the starch content and co-activation were found to result in rise in the Young's modulus and tensile strength, but joint activation ensures an increase in the elasticity of the samples. The kinetic parameters of moisture transfer through composite films were estimated. A distinct compensative effect was found, consisted in a significant increase in the sorption coefficient and a decrease in the diffusion coefficient with increasing starch content.
