Production of Value-Added Composites from Aluminum-Plastic Package Waste via Solid-State Shear Milling Process

Aluminum-plastic multilayer films have been widely used in the packaging industry, but the recycling of such a material is a great challenging task. Herein, we reported a facile route to produce value-added composites with high thermal conductivity and high electrical insulation from aluminum plastic package waste (APPW) for the first time. Briefly, solid-state shear milling (S3M) technology was applied to prepare ultrafine APPW powder and exfoliate expandable graphite (EG) into graphite nanoplatelets (GNPs) with a lateral dimension of 1-5 mu m which constructed the conductive network. For the blocking of electron transfer through the aluminum/GNPs network in composites, an in situ oxidation process was employed for aluminum flakes to form a nano-Al2O3 electronic insulation layer around the aluminum flakes, whereas phonons can transport through this barrier layer easily. As a result, the APPW/GNPs composites exhibit an excellent balance of thermal conductivity and electrical insulation, well above all reported data to date on graphite or graphene/polymer composites, with a thermal conductivity of 1.7 W/(m K) and electrical conductivity of 10(-10) S/cm. Furthermore, enhanced mechanical strength and stiffness are achieved in APPW/GNPs composites. Such materials could have potential applications in the electronic industry and turn an environmental pollutant into a valuable resource.