Poly(3-hydroxybutyrate-Co-3-hydroxyvalerate) (PHBV) Based Biocomposites Containing Coffee Silverskin: Injection Moulding and Migration Performances Assessment

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is among the most attracting low environmental impact polymeric materials. Coffee Silverskin (CS), an agro-food residue, has been compounded in variable amounts into a PHBV matrix in the presence of acetyl tributyl citrate (ATBC) as plasticizer, and calcium carbonate (CaCO3) as filler, to produce biocomposites through a pre-industrial scale melt extrusion technique. Thermal, morphological and mechanical properties have been investigated in order to validate whether these PHBV/CS based biocomposites could be used to manufacture moulded items, e.g. coffee capsules body. The increasing concentration of CS in PHBV improves the stiffness and the heat deflection temperature properties of the biocomposites. Coffee capsules body have been produced by injection moulding starting from the optimized formulations, based on the PHBV/CS system, and were characterized in terms of migration properties in contact with simulants. Notably, the overall migration at 100 °C was below the limit (10 mg/dm2) required for plastic materials in food contact applications.