LAUSR

Abstract The objective of the work was to investigate how different concentrations of sodium caseinate (SC) and chitosan (CH) affect the structure and physical properties of the obtained blended films. Different concentrations of SC and CH solution were mixed in a proportion of 1:1 (v/v) to obtain 16 different blends. The structure of film forming solutions and films were studied by phase separation behavior, rheological behavior and microstructure characterization. The properties of the films were investigated by the moisture adsorption behavior, water vapor permeability (WVP) and mechanical analysis. Rheological behavior of samples highlighted that chitosan and caseinate electrolyte complexes are function of the biopolymer concentration and ration between CH and SC. Blend film showed improved mechanical properties respect to CH films. The sample with a SC/CH ratio equal to 2 and surface density of 10 mg cm −2 has the greatest elastic modulus, tensile strength and elongation at break values. The hydrophilic nature of films is reduced by increasing biopolymer concentration and ratio between CH and CS even if the barrier proprieties of blend film were not optimized respect to chitosan film.