Thermal properties of hydrogel-clay nano-composites

Abstract

Hydrogels are one of the most widely employed materials in biological, medical and technological areas. However, the use of hydrogels sometimes is restricted due to their specific properties. It is well-known that polymeric nanocomposites reinforced with clays show valuable improvements in their properties. In this work, eco-friendly composite hydrogels were prepared employing polyvinylalcohol (PVA) and bentonite (abundant and low cost smectite-type clay in Argentina) as raw materials through the previously optimized freezing-thawing (F-T) crosslinking method. Different nanocomposite hydrogels were obtained by varying the corresponding reactor feed. These materials have been recently chemically, morphologically and mechanically analysed in a recent work. Specifically, in the present work, thermal degradation behaviour of PVA-bentonite hydrogels was studied. Kinetic analytical models were applied to non-isothermal thermogravimetric (TGA) measurements trying to identify the possible mechanism for PVA degradation in the presence of bentonite.