Influência da incorporação de poli(ácido lático) - PLA, de pó de madeira e outros aditivos no comportamento físico-mecânico do poli(hidroxibutirato) - PHB.

Abstract

Polymeric materials are used today in the most varied sectors and the deleterious effects of their application, particularly in the short-term, have led to increasing environmental concern. On the other hand, innovative biodegradable polymers, which promise to offset these effects, are still hampered by their high cost and often unsatisfactory performance. In view of this fact, a study was made of poly(hydroxybutyrate)/poly(lactic acid) - PHB/PLA; poly(hydroxybutyrate)/wood powder-PHB/WP; and PHB/other modifiers (starch, rice chaff, sugarcane bagasse fiber) blends and compounds. These blends and compounds were evaluated and characterized using the following techniques: Melt Flow Index (MFI), Capillary Rheometry, Torque Rheometry, Differential Scanning Calorimetry (DSC), Thermogravimetry (TG), Dynamic Mechanical Thermal Analysis (DMTA), Physical and Mechanical Tensile and Impact tests, Heat Deflection Temperature (HDT) tests, and Scanning Electron Microscopy (SEM). The results obtained indicated the immiscibility of the PHB/PLA blends. The absence of transesterification reactions in the PHB/PLA blends was verified by TG. From the standpoint of mechanical properties, the PHB/PLA blends generally displayed characteristics superior to those of pure polymers. On the other hand, the polymeric compounds containing wood powder displayed rigidity and greater brittleness due to the lack of adhesion between the wood powder and the polymer, as indicated by SEM. This study therefore indicated that it is possible to obtain materials with adequate physical and mechanical characteristics that are viable particularly for short-term applications.