Development of Fibres-Reinforced Biodegradable Composites

In this work, blends of poly(3-hydroxybutyrate) (PHB), the most widespread member of the polyhydroxyalkanoates (PHAs), with wood fibres were investigated to assess the feasibility of producing biodegradable materials suitable for applications in packaging and agricultural environment. Due to its high crystallinity, PHB is stiff and brittle resulting in very poor mechanical properties with low extension at break, which limits its range of application. PHB was compounded successfully with wood fibres up to 30 % by weight in presence of polyethylene glycol (PEG) by extrusion. The composites were characterized by differential scanning calorimetry (DSC) and by scanning electron microscopy (SEM). Their mechanical properties were tested by dynamic mechanical thermal analysis (DMTA) and tensile tests. Preliminary tests in soil were carried out on the samples with wood fibres in order to investigate their biodegradation behavior, and further tests were performed in compost. Polyethylene glycol resulted effective as lubricating agent for the production of composites based on PHB and fibres. The good preliminary biodegradability results in soil showed that the blends PHB/wood fibres appear suitable for the production of natural fibre-reinforced thermoplastic items degradable in agricultural environment