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International audienceThe concentration dependence of specific heat, electrical and thermal conductivities of nanocomposites based on high-density polyethylene (HDPE) filled with silver nanoparticles have been investigated. The composites filled with high filler content show high electrical and thermal conductivities. The dielectric relaxation spectroscopy was used to investigate the electrical properties in the studied systems. The scaling law of electrical percolation was used for an exact estimation of the percolation threshold (Pc). A low electrical percolation threshold was found in the investigated composites. The rule of mixture was sufficient for the prediction of the specific heat dependence of HDPEAg nanocomposites as a function of the weight filler content. The basic models of the thermal conductivity have a tendency to underestimate the measured values for the low and high filler concentrations

A description of a new technology for automatic sorting of plastics, based on X-ray fluorescence detection of tracers, added in such materials is presented. This study describes the criteria for the selection of tracers, and concluded that the most adapted for XRF are some rare earth oxides. The plastics chosen for tracing and identification are the ones contained in ELV and WEEE from which discrimination is difficult for the existing sorting techniques due to their black colour.

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Polypropylene/poly(3-hydroxybutyrate-co-hydroxyvalerate) blend (PHBV) and polyethylene/PHBV blend were prepared by twin screw extruder using preformed copolymer (EVOH-g-PHBV) as compatibilizer or with functional polyolefins that can react in situ with the PHBV phase to form POs-g-PHBV. Scanning electron microscopy shows that by using either EVOH-g-PHBV preformed copolymer or formed copolymers in situ both emulsify the phase interface and reduce the interfacial tension, which result in an enhancement on the mechanical properties of compatibilized blends. Enhancement is more or less pronounced depending on the used PO matrix.