Preparation and Characterization of a Biocomposite Based on Cork Microparticles in Poly(beta-hydroxybutyrate)-co-Poly(beta-hydroxyvalerate) Matrix

摘要

Poly(beta-hydroxybutyrate)-co-poly(beta-hydroxyvalerate) (PHBV) loaded with 1 to 10 wt.% of cork microparticles (CM) were manufactured via compression molding technique. CM were isolated by alkali, bleaching and acid hydrolysis treatments. They were then added to the PHBV matrices via solution casting technique. The filler microparticles showed typical diameters of 10 to 55 mu m. Mechanical tests in tension showed that in PHBV containing 5 wt.% CM the Young's modulus and the tensile strength increased by 50% and 10% respectively. Meanwhile, the elongation at break decreased by 70% for the same CM content. The mechanical behavior of the reinforced composites was discussed in conjunction with the morphology of the samples studied by optical and electron microscopy. The temperature of initial degradation T-id, the temperature at 5% weight loss T-d5% and the temperature of maximum degradation T-dmax increase with increasing CM content by up to 13.6 degrees C, 10.1 degrees C and 12.3 degrees C respectively for the composite of 5 wt.%. The composite with 10 wt.% CM content showed the best thermal stability with temperature increments of 20 degrees C, 14.1 degrees C and 21.5 degrees C respectively. DSC results showed that the presence of CM has a very weak influence on the melting/crystallization behavior of the composites.