High Value Recycle of Waste Cross-Linking Polyethylene with the Contribution of Phosphogypsum to Prepare Composites

This study shows that phosphogypsum (PG) can promote the recycling of waste crosslinking polyethylene (XLPE) cables with the solid-state shear milling ((SM)-M-3) technology. As a kind of milling aid, phosphogypsum (PG) promoted molecular chain breaking and de-crosslinking. The mechanochemistry of co-milling promoted the uniform dispersion of PG in XLPE and the formation of Ca2+ coordinate covalent bonds. Coordinate covalent bonds improved the compatibility and toughness of the composite. The elongation and notch impact toughness of the composites with co-milled PG were 404.6% and 223.6% higher than those of PG without co-milling. In thermoplastic processing, the bound water of PG as an internal lubricant reduced the melt viscosity to achieve self-plasticizing. The balance torque of the composite was reduced by 29.64%, representing a better processing performance. The (SM)-M-3 technology provided a new idea for high-value recycling of PG and waste XLPE, which has great application potential in the chemical industry. [GRAPHICS]