Isothermal degradation kinetics of nanocomposites based on polyhydroxybutyrate (phb) modified clays.

D'AMICO DAVID ALBERTO; L. B. MANFREDI; V. P. CYRAS

Bahia Blanca

Simposio; IX Simposio Argentino de Polímeros (SAP 2011); 2011

Plapiqui

Preparation of blends or nanocomposites, using low percentages of inorganic fillers, is among the routes to improve some of the properties of biodegradable polymers such as thermal and oxidative barrier, when they are compared with traditional composites (Cyras et al., 1999). Montmorillonite (MMT) is among the most commonly used layered silicates because it is environmentally friendly and readily available in large quantities with relatively low cost (Ray and Okamoto, 2003). There are many factors which limit the use of nanocomposite based on biodegradable polymers on industrial scale such as thermal stability, humidity absorption and mechanical properties. In any industrial process, operational variables exist that must be controlled in order to avoid the degradation of the raw materials. When the polymer is processed, in many cases, it is desired the temperature to remain constant, e.g. melting polymer in the mold cavity. To know the limits processing temperatures of the raw materials, it is necessary to characterize their thermal degradation behavior. The aim of the kinetic analysis is the determination of kinetic triplets (i.e. kinetic model, g(a), activation energy, E, and pre-exponential factor, A) for the investigated process. It is suggested that prior to any kinetic analysis, the dependence of E on conversion (a), by isoconversional methods, should be investigated. The purpose of this work is to analyze the thermal degradation behavior of PHB and its nanocomposites (Vyazovkin and Lesnikovich, 1990).