A new method of determining the J-integral fracture toughness of very tough polymers: application to ultra high molecular weight polyethylene.
The thrust of the present work was the development of a new modification to the ASTM E813-89 method for determining the J-integral fracture toughness, JIc, of ductile polymers. The advantages and limitations of the modification, vis a vis the ASTM E813-89 and the hysteresis methods, are presented. The modification was then applied to investigate the effect of sterilization method on the JIc of ultra-high-molecular-weight polyethylene (UHMWPE) specimens that were subsequently aged (heated, in a cylindrical pressure vessel, in oxygen gas at 507 kPa and 70 degrees C for 14 d). Relative to the unsterilized material, it was found that gamma-irradiating the polymer leads to a significant drop in its JIc, while sterilization using either ethylene oxide or gas plasma produced no effect on its JIc. The clinical implications of the present results for the in vivo performance of UHMWPE counterfaces, and, hence, hip and knee arthroplasties, are fully discussed.
Lewis
G
G
Department of Mechanical Engineering, University of Memphis, TN 38152-6576, USA.
Nyman
J S
JS
D006245:Hardness Tests / Q000295:instrumentation / Q000379:methods; D006622:Hip Prosthesis; D006801:Humans; D007720:Knee Prosthesis; D008422:Materials Testing / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D008970:Molecular Weight; D020959:Polyethylene / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*
D011108:Polymers; D020959:Polyethylene