title: Influence of crystallization conditions on the tensile properties of radiation crosslinked, vitamin E stabilized UHMWPE.
abstract: Radiation crosslinking for ultra-high molecular weight polyethylene results in improved wear resistance but a reduction in mechanical properties. Incorporation of vitamin E has been known to decrease the rate of oxidative degradation occurring through radiation crosslinking and prevents the need for post-irradiation melting with subsequent loss of crystallinity. In this study, we aimed to determine the effect of thermal treatments prior to crosslinking on the morphology and tensile properties of vitamin-E-containing polyethylene. Vitamin-E-blended polyethylene was melted and subsequently quenched in ice water in order to induce high rate crystallization. A second group was additionally annealed at 126°C following quenching and all samples were irradiated using electron beam radiation to a dose of 100kGy. The morphology of control, quenched and quench-annealed polyethylene was characterized using small angle x-ray scattering and differential scanning calorimetry. Tensile properties of these polyethylenes were measured before and after radiation crosslinking with equilibrium swelling experiments performed to assess the crosslink density of irradiated samples. This study shows how the tensile properties of polyethylene can be enhanced by varying thermal treatments prior to crosslinking; and thus how it may be possible to offset the reduction in tensile properties afforded by the crosslinking process.
authors.affiliation: Department of Orthopedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
authors.forename: A
authors.initials: A
authors.lastname: George
authors.affiliation: Department of Orthopedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
authors.forename: H D
authors.initials: HD
authors.lastname: Ngo
authors.affiliation: Department of Orthopedic Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States. Electronic address: anuj@alum.mit.edu.
authors.forename: A
authors.initials: A
authors.lastname: Bellare
mesh_terms: D001672:Biocompatible Materials; D003460:Crystallization; D008422:Materials Testing; D011095:Polyethylenes / Q000737:chemistry*; D013718:Tensile Strength; D014810:Vitamin E / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene; D014810:Vitamin E
keywords: Crystallization; Fracture toughness; Joint replacement; Mechanical properties; Polyethylene