New Bio-Composites Based on Polyhydroxyalkanoates and Posidonia oceanica Fibres for Applications in a Marine Environment

摘要

Bio-composites based on polyhydroxyalkanoates (PHAs) and fibres of Posidonia oceanica\ud(PO) were investigated to assess their processability by extrusion, mechanical properties, and potential\udbiodegradability in a natural marine environment. PHAs were successfully compounded with PO\udfibres up to 20 wt%while, at 30 wt%of fibres, the addition of 10 wt%of polyethylene glycol (PEG 400)\udwas necessary to improve their processability. Thermal, rheological, mechanical, and morphological\udcharacterizations of the developed composites were conducted and the degradation of composite\udfilms in a natural marine habitat was evaluated in a mesocosm by weight loss measure during an\udincubation period of six months. The addition of PO fibres led to an increase in stiffness of the\udcomposites with tensile modulus values about 80% higher for composites with 30 wt % fibre (2.3 GPa)\udcompared to unfilled material (1.24 GPa). Furthermore, the impact energy markedly increased with\udthe addition of the PO fibres, from 1.63 (unfilled material) to 3.8 kJ/m2 for the composites with 30 wt %\udPO. The rate of degradation was markedly influenced by seawater temperature and significantly\udpromoted by the presence of PO fibres leading to the total degradation of the film with 30 wt % PO in\udless than six months. The obtained results showed that the developed composites can be suitable to\udmanufacture items usable in marine environments, for example, in natural engineering interventions,\udand represent an interesting valorisation of the PO fibrous wastes accumulated in large amounts on\udcoastal beaches.