Characterization and properties of non-granular thermoplastic starch-Clay biocomposite films

Biocomposite films were prepared using as raw materials non-granular normal maize starch plasticized with glycerol and Na-montmorillonite clay particles in various concentrations. The physicochemical properties of films were studied, and their structure and morphology were investigated using XRD analysis, Thermal analysis, Scanning Electron Microscopy combined with Element Microanalysis. The mechanical characteristics were investigated through tensile test. The results indicated that the presence of clay particles in the starch matrix reduced the water absorption rate of films in comparison to starch films containing glycerol but not clay particles. The biocomposite films exhibited enhanced tensile properties at low glycerol and high clay contents. Best results were obtained for films containing 20 wt% glycerol and 10-20 wt% clay content. It is suggested that the non-granular maize starch, is a suitable raw material for the preparation of biocomposite films with improved structural and mechanical characteristics in comparison to films prepared using granular starch.