Poly(3-Hydroxybutyrate-co-3-Hydroxyvalerate)/ Purifi ed Cellulose Fiber Composites by Melt Blending: Characterization and Degradation in Composting Conditions

Novel biodegradable composites based on poly(3-hydroxybutirate-co-3-hydroxyvalerate) (PHBV) and different contents of purifi ed alpha-cellulose fi bers (3, 10, 25 and 45%) were prepared by melt blending and characterized. The composites were characterized by scanning electron microscopy (SEM), wide-angle X-ray scattering (WAXS) experiments, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanic analysis (DMA) and Shore D hardness measurements. Disintegrability under composting conditions was studied according to the ISO 20200 standard. Morphological results showed that high dispersion of the fi bers was achieved during mixing. Good adhesion on the fi ber-matrix interface was also detected by SEM. The addition of low and medium cellulose contents did not result in lower thermal resistance with respect to the neat PHBV. A reinforcing effect of the cellulose fi bers was detected in all samples, this effect being more pronounced at high temperatures. The composting results show that the addition of the fi bers did not affect the disintegrability of the PHBV, and thus compostable “green” low-cost PHBV/cellulose composites can be obtained.