Solid state deformation processing of crosslinked high molecular weight polymeric materials

• Main Authors: HAWKINS H. GENE, SALYER BRIAN D, GUNTER JAMES E, FREEDMAN JORDAN H, SCHROEDER DAVID WAYNE
• Format: Patent
• Language: English
• Published: 16.06.2009
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CHEMISTRY; COMPOSITIONS BASED THEREON; GENERAL PROCESSES OF COMPOUNDING; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS, SLAG, OR MIXTURESCONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; WORKING CEMENT, CLAY, OR STONE; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL; WORKING-UP

Solid-state deformation processing of crosslinked high molecular weight polymers such as UHMWPE, for example by extrusion below the melt transition, produces materials with a desirable combination of physical and chemical properties. Crosslinked bulk materials are heated to a compression deformable temperature, and pressure is applied to change a transverse dimension of the material. After cooling and stress relieving, a treated bulk material is obtained that has enhanced tensile strength in the axial direction orthogonal to the dimension change. In preferred embodiments, medical implant bearing materials are machined from the treated bulk material with the in vivo load bearing axis substantially parallel or coincident with the axial direction of the treated bulk material.