Mechanical recycling of cross-link polyethylene: Assessment of static and viscoplastic properties

Abstract

Fundamentally, there are two recycling methods for plastics: material recycling (including primary, secondary, and tertiary recycling, i.e. hydrolysis and glycolysis) and energy recycling or quaternary recycling. Since the former method replenishes material resources, it is favored where it is possible, i.e. for none polluted or mixed product. At some point after repeated use, the material may commence to degrade, by then it is destined to energy conversion or total breakdown subjected to incineration, gasification or pyrolysis. This work considers the material recycling of LDPE. LDPE represents nearly of 8-10% of the total MSW waste received at the landfill. Initially thermal analysis based on Simultaneous Thermal Analysis (STA) and Differential Scanning Calorimetry (DSC) is carried out to observe the plastic thermal behavior of two successively molded samples. The samples are remolding using the thermosientific mini extruder and the HAAKE MiniJet II injected. The mechanical and thermomechancial properties are assessed using uniaxial static and dynamic tests under well controlled conditions. Mild variation is obtained in the thermal behavior to the two samples observed by the similarity in melting, extent of thermal stability, and onset and end of degradation. However, the mechanical behavior between the three samples clearly demonstrates the gain in total modulus and lower tan delta for the cross-linked product but with a reversion to original LDP behavior following the molding of the waste. This work support successive material recovery for cable plastics with an additional cross-linking to the rejected waste.