Hybrid starch/silica films with improved mechanical properties

Environmental concern has increased the research in development of biodegradable packaging. Although there are many reports about starch films, their physicochemical properties need to be improved, and the introduction of an inorganic compound is an alternative to be applied. However, there are few reports about the development of biodegradable hybrid organic–inorganic films for food packaging. Therefore, the preparation of biodegradable films was proposed by using sol–gel and casting techniques, based on starch and glycerol as plasticizers, with the incorporation of an alkoxide precursor containing silicon, TEOS (tetraethyl orthosilicate) in different concentrations. Morphological, thermal, optical, and mechanical properties, water solubility, swelling, and water vapor permeability were evaluated. The addition of TEOS was more efficient when it underwent pre-hydrolysis before incorporation into the film-forming solution, significantly interfering with the results of mechanical, optical, and barrier properties. The silica phase was uniformly incorporated into the polymer, presenting micrometric domains. The hybrid films produced have satisfactory properties for application as biodegradable packaging.