From Waste to Wealth: Upcycling Waste Polypropylene/ Polyethylene for Thermal Management via Pressure-Induced, Flow-Enhanced Segregated Structurizing with Hexagonal Boron Nitride

The low value of recycled products is the main roadblock for sustainable development of polymers. In this work, waste polypropylene and waste polyethylene were chosen to be recycled for value-added thermal management with the addition of hexagonal boron nitride (hBN). Through specific design of melt flow indexes (MFIs), we proposed a novel pressure-induced, flow-enhanced segregated structurization (PiF-SS) process. The segregated structures were visually confirmed by various microscopies at different scales. The highest in-plane thermal conductivities of similar to 7.48 W/mk was obtained for the sample with a low hBN loading of 20 wt %. Ultimately, we evaluated the thermal management performance of all samples with various compositions. In this work, we believe that the concept of combinational utilization of a high-MFI polymer and a low-MFI polymer to perform PiF-SS can not only work for the sustainable reuse of waste polymers but also be used for manufacturing advanced functional materials.