Process of making ultra high molecular weight polyethylene prosthetic devices
AssigneesThe General Hospital Corporation, Massachusetts Institute of Technology
InventorsEdward W. Merrill, William H. Harris, Premnath Venugopalan, Murali Jasty, Charles R. Bragdon, Daniel O. O'Connor
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Abstract
The present invention relates to a medical prosthesis for use within the body, which is formed of ultra high molecular weight polyethylene having a polymeric structure with less than about 50% crystallinity, less than about 290 Å lamellar thickness and less than about 940 MPa tensile elastic modulus, so as to reduce production of fine particles from the prosthesis during wear of the prosthesis. The present invention also relates to methods of manufacture of such devices and material used therein.
Claims12
A method for making highly entangled and crosslinked ultra high molecular weight polyethylene, comprising the steps of:
- providing conventional ultra high molecular weight polyethylene;
- surrounding said ultra high molecular weight polyethylene with an inert material that is substantially free of oxygen;
- heating said ultra high molecular weight polyethylene above the melting temperature of said ultra high molecular weight polyethylene for a time sufficient to enable the formation of entangled polymer chains in said ultra high molecular weight polyethylene;
- irradiating said heated ultra high molecular weight polyethylene so as to trap the polymer chains in the entangled state;
- and
- cooling said irradiated ultra high molecular weight polyethylene to about 25° C.
Dependencies are inferred from the claim text.