Injection-Molded Ultrahigh Molecular Weight Polyethylene Material with Improved Moldability for Artificial Joint Implants Design

Fabrication of pure ultrahigh molecular weight polyethylene (UHMWPE)-based artificial joint implants is a bottleneck problem as it is only limited to quasistatic approaches that have low efficiency due to the high density of fusion defects. The main objective of this work is to improve the moldability of UHMWPE using the injection molding technique while maintaining its superior mechanical integrity. Groups of UHMWPE samples are injected at barrel melting temperatures of 300, 320, 340, and 360 °C, at various injecting pressures. The high-temperature melting (HTM) allows the fabrication of robust UHMWPE samples using injection molding with an improved yield stress of 29.63 ± 3.19, compared to 23.0 ± 0.6 and 17.8 ± 0.75 achieved by HTM compression molding and conventional compression molding, respectively. Moreover, the scanning electron microscopy (SEM) results suggest an almost complete elimination of all fusion defects, and that is supported by the outstanding tensile strain at breaks reaching up to approximately 1300%. The thermochemical properties of the injection-molded UHMWPE samples are tested as well to investigate the impact of HTM on their characteristics. Moreover, the materials’ biocompatibility and wear are assessed. This study sets up a new approach to fabricate high-performance injection-molded UHMWPE joint implants by HTM.