Biodegradable composites based on flax/polyhydroxybutyrate and its copolymer with hydroxyvalerate

The present paper focuses on short flax fibre reinforced composites based on polyhydroxybutyrate (PHB) and its copolymer with hydroxyvalerate (HV). The effect of the fibre and copolymer content on the mechanical properties of the composites is being discussed. Furthermore, the influence of manufacturing method (compression moulding of non-woven mats and injection moulding of short fibre compounds) and processing conditions (cooling temperature and annealing) on the mechanical properties of the composites is being investigated. Finally, the biodegradability of the aforementioned composites expressed as weight, stiffness and strength loss as a function of burrier time is presented on the example of injection moulded flax/PHB/HV composites. It can be concluded that the addition of flax fibres along with controlled processing conditions seems to be a convenient way of toughening of the PHB matrix. Composites manufactured through injection moulding exhibited lower impact strength than those manufactured through compression moulding. Based on the biodegradation study of PHB/HV composites it can be concluded that the tensile properties drop significantly in the initial stage of degradation. The drop in tensile properties is more gradual in the later stages of biodegradation.