SOLID STATE DEFORMATION PROCESSING OF CROSSLINKED HIGH MOLECULAR WEIGHT POLYMERIC MATERIALS

• Main Authors: HAWKINS H. GENE, SALYER BRIAN D, SCHROEDER DAVID W, GUNTER JAMES E, FREEDMAN JORDAN H
• Format: Patent
• Language: English
• Published: 12.06.2008
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; BANDAGES, DRESSINGS OR ABSORBENT PADS; CHEMISTRY; COMPOSITIONS BASED THEREON; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF,TUBULAR STRUCTURES OF THE BODY, E.G. STENTS; FILTERS IMPLANTABLE INTO BLOOD VESSELS; FIRST-AID KITS; FOMENTATION; GENERAL PROCESSES OF COMPOUNDING; HUMAN NECESSITIES; HYGIENE; MEDICAL OR VETERINARY SCIENCE; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; PERFORMING OPERATIONS; PROSTHESES; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; TREATMENT OR PROTECTION OF EYES OR EARS; 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 combination of high tensile strength and high oxidative stability. The materials are especially suitable for use as bearing components in artificial hip and other implants. Treated bulk materials are anisotropic, with enhanced strength oriented along the axial direction. The material is oxidatively stable even after four weeks of accelerated aging in a pressure vessel containing five atmospheres of oxygen (ASTM F2003). Because of its oxidative stability, the deformation processed material is a suitable candidate for air-permeable packaging and gas sterilization, which has thus far been reserved for remelted crosslinked UHMWPE.