CONICET | Buscador de Institutos y Recursos Humanos

Clay based nanocomposites show notable improvements in several properties in comparison with a polymer or conventional micro-composites, such as increased strength and heat resistance and decreased gas permeability and flammability. The hydrophilic character of clays promotes dispersion of these inorganic crystalline layers in water soluble polymers. Polyvinylalcohol (PVOH) is a synthetic water soluble polymer, non-toxic, with excellent film forming properties. It is characterized by strong hydrophilic and hydrogen bonding character. It has been studied for medical and biomedical applications, as well as for food packaging applications. It is also an interesting polymer for the synthesis of biocompatible high-strength hydrogels. However, some applications are stillrestricted because of its high degree of swelling and solubility in water, and its limited mechanical properties. Some of these drawbacks can be improved by the incorporation of reinforcement like clays. In this work, PVOH has been used for the synthesis of nanocomposites in different ways: films (by casting)and hydrogels (by freezing-thawing). In both cases, bentonite (clay) was used as reinforcement. PVOH/clay nanocomposites can be easily obtained because, as both of them are hydrophilic, the clay can be incorporated into the PVOH without pre-treatments by simply dispersing the two components in water. The aim of this work was to study the chemical, barrier and thermal properties of the nanocomposites in order to analyze the effect of clay incorporation on the general behavior of PVOH matrices. It was determined that the incorporation of bentonite produces a decrease on the water vapour transmission rate which is very important for both selected applications. On the other hand, that filler was able to enhance the mechanical performance of neat PVOH matrices measured by tensile properties.