Solid-state shear pulverization of post-industrial ultra-high molecular weight polyethylene: Particle morphology and molecular structure modifications toward conventional mechanical recycling

Ultra-high molecular weight polyethylene (UHMWPE) is one of the most prominent high-performance thermoplastics for biomedical, leisure, and coating applications. Large-scale recycling of UHMWPE is extremely difficult due to the high melt viscosity of the material as well as its exceptional chemical resistance and impact strength. There is a need for a commercially scalable methodology that can process the waste feedstock for mechanical recycling while sustaining the outstanding physical properties of the material. Solid-state shear pulverization (SSSP) is a continuous, twin-screw extruder-based processing technique in which the low-temperature application of shear and compressive forces impart changes in structure at different length scales to overcome the challenges of difficult-to-recycle polymers. This paper investigates the use of SSSP in mechanically recycling post-industrial scrap UHMWPE (rUHMWPE) material from a local ski and snowboard manufacturer. The SSSP-processed particles are flat, micron-scale flakes with enhanced surface area, which can sinter very quickly when compression molded. The molded rUHMWPE samples in turn exhibit enhanced ductility and toughness compared to the as-received scrap material, based on the tunable mechanochemical modification of the ethylene chains.

Automated summary

Ultra-high molecular weight polyethylene (UHMWPE) is a high-performance thermoplastic widely used in biomedical, leisure, and coating applications. However, its recycling is challenging due to its high melt viscosity and exceptional chemical resistance. This study investigates the use of a processing technique called solid-state shear pulverization (SSSP) for mechanically recycling post-industrial scrap UHMWPE materials and improving their ductility and toughness.