Mechanics of ZnO morphological dependence on wear resistance of ultra high molecular weigh polyethylene
Article
Sharma, RK, Nisar, A, Balani, K. (2017). Mechanics of ZnO morphological dependence on wear resistance of ultra high molecular weigh polyethylene
. 65 149-158. 10.1016/j.euromechsol.2017.03.010
Sharma, RK, Nisar, A, Balani, K. (2017). Mechanics of ZnO morphological dependence on wear resistance of ultra high molecular weigh polyethylene
. 65 149-158. 10.1016/j.euromechsol.2017.03.010
Ultra high molecular weight polyethylene (UHMWPE) is widely used as an acetabular cup liner for cartilage replacement in hip arthroplasty. The implant failure mainly occurs due to the wear of polymeric liner. Thus, in order to increase the wear resistance of polymer liner, 20 wt % ZnO is reinforced in compression molded UHMWPE. Herein, the role of various ZnO morphologies, viz. microrods (R), nanoparticles (NP), and microdisks (D) is assessed on the tribological properties (such as wear rate and coefficient of friction) of UHMWPE matrix. Sliding wear (bulk length scale) and fretting wear (micrometer length scale) have shown highest wear resistance of ZnO(D) reinforced UHMWPE. On one hand, ZnO(R) experience pronounced buckling and weak interfacing in matrix and show an increased sliding wear rate of 8.08 × 10−14m3/Nm (when compared to that of 5.88 × 10−14 m3/Nm for UHMWPE). Contrastingly, ZnO(D) exhibited strong interfacing and demonstrated a reduced wear rate of 1.80 × 10−14 m3/Nm. A similar trend of wear rate was observed at micrometer length scale i.e. least (1.17 × 10−21 m3/Nm) for ZnO(D) and highest (3.19 × 10−21 m3/Nm) for ZnO(R) when compared to that of UHMWPE (2.40 × 10−21 m3/Nm). Damage mechanism in ZnO(NP) is attributed to the formation of tribofilm on counter surafce. Further, wear-resistance rendered by ZnO morphologies is found to be higher (up to 19%) in sliding wear when compared to that of fretting. In summary, enhanced tribological resistance of UHMWPE-ZnO(D) can make it a potential polymeric liner in total joint arthoplasty.
