UHMWPE/HA biocomposite compatibilized by organophilic montmorillonite: An evaluation of the mechanical-tribological properties and its hemocompatibility and performance in simulated blood fluid

Abstract

The low interaction between ultra high molecular weight polyethylene (UHMWPE) and hydroxyapatite (HA) has been one of the problems that results in a composite material with low mechanical and tribological performance due to the formation of agglomerates and microstructural defects. These properties affect the quality of the material when used for total joint implants and other applications in hard tissue engineering. This study investigated the effect of the addition of organophilic bentonite (BO) into the interface HA and UHMWPE. The composite was prepared by wet milling in a planetary mill and then by compression molding. The composites samples were characterized by XRD, FTIR, SEM and DSC. The tensile and tribological mechanical properties were also evaluated. Furthermore, in vitro degradation using simulated blood fluid (SBF) and hemocompatibility was performed. The results suggest that the addition of 10 wt% of organophilic bentonite improved the interface between the UHMWPE and HA by exfoliation/intercalation, presenting the best results of modulus of elasticity, tensile strength, coefficient of friction and rate of wear. The composite UHMWPE/HA/BO-10 wt% presented low water absorption and induced the growth of apatite crystals on its surface. Additionally, its hemocompatibility index is within normal limits and induced a low adhesion and agglomeration of platelets in contact with human blood, evidencing that the UHMWPE/HA/BO-10 wt% composite is promising for application in bone tissue engineering.