Effects of the sintering temperature on the superior cryogenic toughness of ultra-high molecular weight polyethylene (UHMWPE)

Abstract

Higher requirements for the performance of cryogenic materials bring new challenges to the design and preparation of cryogenic materials. Fortunately, ultra-high molecular weight polyethylene (UHMWPE) displays the potential to become the next generation of cryogenic materials due to its many superior properties, especially its outstanding toughness. In this study, we sintered UHMWPE powders under different sintering temperatures and found that higher sintering temperatures could lead to the final product having better toughness. Surprisingly, the impact strength at −196 °C of UHMWPE sintered at 220 °C is approximately 4.2 times that of polychlorotrifluoroethylene (PCTFE), whose low-temperature impact performance is almost the best among the existing engineering plastics. The maximum cryogenic tensile strength is 158.6 MPa for sintered UHMWPE, while that of PCTFE is only 117.8 MPa. We attributed such outstanding cryogenic toughness to many chain entanglements and proposed a potential mechanism based on scanning electron microscopy (SEM), dynamic mechanical analysis (DMA), differential scanning calorimeter (DSC), and X-ray scattering diffraction (XRD) characterizations. In summary, sintered-mould UHMWPE can be a cost-effective candidate for cryogenic materials in industry due to its superior impact resistance even at −196 °C and other excellent mechanical properties.