PLA-PHB BLENDS: THE EFFECT OF DIFFERENT COMPATIBILIZERS AND THE PROCESS PARAMETERS ON MECHANICAL AND RHEOLOGICAL PROPERTIES

In recent years, it was developed an interest in biodegradable plastics due to the environmental impact of conventional plastics. Particularly there has been an increase in the use of Polylactic acid (PLA). This is one of the most widely used and studied biopolymers. It is a highly transparent, amorphous and rigid material, with a glass transition temperature of around 60°C. It can been processed as a conventional thermoplastic polymer. The main drawbacks of PLA are its high brittleness and low thermal stability. The ways of overcoming these problems are to use plasticizer, copolymerization with others components, making composites and blending with other polymers to obtain a biodegradable plastic with high mechanical properties intermediate between two polymers.. In this work, a blend with Polyhydroxybutyrate (PHB) was chosen. Specifically, we have studied different compatibilizer systems with different chemical structure to improve the miscibility between PLA and PHB; the thermal and mechanical properties of formulated blends were investigated. Furthermore the process conditions, in terms of, screw configuration and screw speed, have been optimized in order to improve the miscibility of the two phase.