The influence of concave dimples on the metallic counterface on the wear of ultra-high molecular weight polyethylene

2011 ◽  
Vol 226 (6) ◽  
pp. 455-462 ◽  
Author(s):  
Xincong Zhou ◽  
Alison L Galvin ◽  
Zhongmin Jin ◽  
Xinping Yan ◽  
J Fisher
Keyword(s):  
Molecular Weight ◽  
Surface Roughness ◽  
Stainless Steel ◽  
High Molecular Weight ◽  
Smooth Surface ◽  
High Nitrogen ◽  
Acetabular Cup ◽  
Reference Case ◽  
High Nitrogen Stainless Steel ◽  
Ultra High Molecular Weight

The aims of this study were to investigate how the dimples on a metallic counterface affect the wear rate of ultra-high molecular weight polyethylene (UHMWPE) in a multi-directional reciprocating pin-on-plate machine. The plates were high nitrogen stainless steel, representing the femoral head material. The pins used in this study were of ultra-high molecular weight polyethylene GUR 1120, which represents the material used in an acetabular cup. Three different cases were investigated: a smooth surface without dimples as a reference case, a surface with medium dimples with an average valley of 2.3 µm and a surface with large dimples with an average valley of 5.9 µm. It was found that all the dimples investigated did not improve the lubrication, but instead increased the surface roughness; consequently, the wear of UHWMPE was slightly increased.

scholarly journals Ultra-High-Molecular-Weight-Polyethylene (UHMWPE) as Desired Polymer Material for Biomedical

2021 ◽  
pp. 11-16
Author(s):  
Assma Said
Keyword(s):  
Molecular Weight ◽  
Impact Strength ◽  
High Molecular Weight ◽  
Moisture Absorption ◽  
Body Part ◽  
The Body ◽  
Clear Understanding ◽  
Acetabular Cup ◽  
Standard Material ◽  
Ultra High Molecular Weight

It is very important that any materials used as implant material work in harmony with the body. There will be drawback with every material. No matter how good, as nothing can be 100% identical as the natural human tissue. The body operates in an environment at a constant temperature of 37°C and pH of 7.25, so choice of materials will have to withstand these conditions. Incorrect use of material can cause rejection by the body, infection and even cancer, leading to more pain and discomfort by the patient. In turn the possibility of even further damage to the joint. The implant must work in the same way as the body part it is replacing- clear understanding of how the joint works is needed. Ultrahigh molecular weight polyethylene is considered as the standard material for Artificial joints to decrease the total weight and the wear rate to make it more flexible. This is what makes Ultra-High-Molecular-Weight-Polyethylene (UHMWPE) such an appropriate polymer. It is very widely used in total hip and knee joint replacements having the highest known impact strength of any thermoplastic presently made, can highly withstand abrasion, and has a very low coefficient of friction. Therefore, these properties, connected with extremely low moisture absorption, make UHMWPE especial material for the medical industry due to good industrial impact and wear resistance sliding applications. For moving joints, the friction would be damaging without the natural lubrication. In implant components this does not exist, however UHMWPE is self-lubricating, making it ideal for component such as an acetabular cup, which would wrap around a metallic femoral head in a hip joint. Also, UHMWPE has high impact strength, high toughness, and low elastic modulus, but it has disadvantages such as low tensile, transverse and compressive strengths with high creep rate. This review article deals with the history of UHMWPE, its material properties that make it an ideal candidate for total joints, implant-component fabrication procedures and provides insights as to why some of the implants eventually fail.

S0202-2-2 Influence of surface roughness on tribological characteristics of ultra-high molecular weight polyethylene

2009 ◽  
Vol 2009.5 (0) ◽  
pp. 47-48
Author(s):  
Yoshitaka NAKANISHI ◽  
Mutsumi TOUGE ◽  
Hidehiko HIGAKI ◽  
Ken SHIMOTO ◽  
Akihisa KUGOTA ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Surface Roughness ◽  
High Molecular Weight ◽  
Tribological Characteristics ◽  
Ultra High Molecular Weight

The Wear of High Molecular Weight Polyethylene—Part I: The Wear of Isotropic Polyethylene Against Dry Stainless Steel in Unidirectional Motion

1978 ◽  
Vol 100 (2) ◽  
pp. 208-218 ◽  
Author(s):  
J. R. Atkinson ◽  
K. J. Brown ◽  
D. Dowson
Keyword(s):  
Molecular Weight ◽  
Stainless Steel ◽  
Steady State ◽  
Wear Rate ◽  
High Molecular Weight ◽  
Transfer Film ◽  
Fatigue Wear ◽  
Ultra High Molecular Weight ◽  
Sliding Distance ◽  
Unidirectional Motion

The wear of surgical grade ultra-high molecular weight polyethylene against stainless steel has been studied for unidirectional motion. After a short wearing-in period, two distinct steady-state regions appear on the wear graphs. In the first section adhesion is the predominant wear mechanism and a transfer film of polymer builds up on the steel counterface. After a certain sliding distance, determined by the load, the adhesive mechanism is augmented by fatigue wear and the wear rate increases sharply and remains constant at the new value.

The Wear of High Molecular Weight Polyethylene—Part II: The Effects of Reciprocating Motion, Orientation in the Polyethylene, and a Preliminary Study of the Wear of Polyethylene Against Itself

1982 ◽  
Vol 104 (1) ◽  
pp. 17-22 ◽  
Author(s):  
K. J. Brown ◽  
J. R. Atkinson ◽  
D. Dowson
Keyword(s):  
Molecular Weight ◽  
Stainless Steel ◽  
High Molecular Weight ◽  
Wear Surface ◽  
Wear Mechanisms ◽  
Molecular Orientation ◽  
Reciprocating Motion ◽  
Preliminary Study ◽  
Ultra High Molecular Weight

The wear of ultra-high molecular weight polyethylene against relatively smooth, dry stainless steel takes place by the same basic wear mechanisms whether unidirectional or reciprocating motion is used, but reciprocating motion produces slightly less wear overall. The effect of molecular orientation in the polyethylene has been studied and it has been shown that orientation perpendicular to the wearing surface is undesirable, whereas orientation parallel to the wear surface is mildly beneficial. The wear of polyethylene against itself is relatively severe and is largely determined by the temperatures reached by the rubbing surfaces.

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