Preparation and characterization of nanocomposites based on biodegradable polyesters and modified clays.

ROMINA OLLIER; DAVID A. D’AMICO; WALTER F. SCHROEDER; VERA A. ALVAREZ; CYRAS, VIVIANA P.

Foz de Iguazú

Congreso; 13er Congreso Internacional en Ciencia y Tecnología de Materiales (SAM-CONAMET); 2013

The study of materials is one of the major areas of science, with legions of researchers in chemistry and materials science working on this topic. Bionanocomposites could work towards remedying some of the problems related to plastics in the environment. The polyhydroxybutyrate (PHB) is a biodegradable polyester produced by microorganisms from renewable resources. Its main advantage is the low gas permeation, similar to that of low density polyethylene. In addition, it is very fragile and its melting temperature is very close to the degradation process, so its processing window is very narrow. Polycaprolactone (PCL) is a chemically synthesized, linear, semicrystalline and biodegradable polyester that can be processed using conventional techniques and is suitable for a number of potential industrial applications. Until now, the main drawback of PCL to replace commodities for packaging and disposable polymer applications was the relative high price and some inferior properties which have limited their large-scale production as a substitute of traditional polymers. It is well known that the performance of these polymers can be greatly enhanced by the addition of nanometer-size inorganic fillers, such as layered silicates producing nanocomposites with improved the barrier, mechanical and thermal properties. To study the effect of adding a nanofiller to the properties of two different biodegradable polyesters (PHB and PCL), films of nanocomposites were prepared containing 4% W / W of three kinds of montmorillonites with different chemical modifications. The films were obtained by casting process in Petri dishes. Thermal characterization of films was obtained by differential scanning calorimetry and thermogravimetric analysis. The morphology of nanocomposites was studied by X-ray diffraction. The effect on the hydrophobicity by adding different clays was measured by means of the drop test. Finally, the mechanical properties of nanocomposites were studied by uniaxial tensile test and dynamic mechanical assays.