Enhanced Thermal Stability of Biodegradable Poly (3 Hydroxybutyrate)/Layered Silicate Nanocomposites

Abstract

Polymer nanocomposites are a class of materials that has already gained a big popularity among researchers both in academia and industry due to their exceptional properties, which are superior to those of the virgin polymers and of the conventional composites [1]. These hybrid materials consist of a polymer matrix in which inorganic particles with at least one dimension in the nanometer scale are homogeneously dispersed. In the case of polymer layered silicate nanocomposites, the high aspect ratio particles interact with the polymer matrix and improve substantially many physical properties of the pristine polymer including enhanced mechanical characteristics and barrier resistance, decreased flammability and increased biodegrability in the case of biodegradable polymers. Recently, biodegradable and biocompatible polymers have received significant attention because they are environmentally friendly and are extensively used in biomedical applications. Poly (3-hydroxybutyrate)(PHB) is rapidly gaining recognition as one of the most promising biopolymers [2]. PHB is a linear, aliphatic polyester produced by different types of microorganisms. However, the poor thermal stability at temperatures slightly higher than its melting point restricts the application field of PHB. In the present work, various loadings of montmorillonite organically modified by octadecylamine (C18MMT) were dispersed in PHB by the melt intercalation method. The aim was to produce hybrid material with improved thermal properties over the pristine PHB. Morphological characterization of the composites was conducted by x-ray diffraction analysis (XRD). The effect of clay content on the thermal properties of the material was studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA)