Polymer Nanocomposite Artificial Joints

Abstract

Artificial joints (AJ) often have a polymeric component to decrease the wear rate and the total weight at the same time and make it more flexible. Ultrahigh molecular weight polyethylene (UHMWPE) is considered as the standard material for these applications. Therefore, UHMWPE has been reinforced by many of the nanomaterials, hoping to improve the tribology characteristic, which is considered as the most important factor in determining the life span of AJ. However, all attempts were in laboratory scale and did not live up to the actual implementation due to the high viscosity of UHMWPE, leading to poor dispersion with bulk components. This chapter aims to explain in detail a novel technique to produce a real UHMWPE nanocomposite (UNC) hip cup using the paraffin oil dispersion technique and tested by an artificial joint simulator (AJS), which was designed by the author. The chapter contains three parts: the first part starts with a brief account of AJ and then illustrates the AJ polymeric components. The wear behavior of the polymeric components is also presented. The second part reviews some previous attempts for the synthesis of UNC and the common nanomaterials [carbon nanofiber (CNF), carbon nanotubes (CNT), and graphene (GA)], which are used as a nanofiller. The problems that had arisen during the mixing process and UNC characterizations are also presented. For the third part, the chapter concludes by explaining a novel technique to produce UHMWPE hip cup reinforced by CNT using the paraffin oil dispersion technique and testing by AJS, which was designed especially for this.