title: A study of the nanostructure and tensile properties of ultra-high molecular weight polyethylene.
abstract: Ultra-high molecular weight polyethylene (UHMWPE) has gained worldwide acceptance as a bearing material used in orthopaedic implants. Despite its widespread use, inherent properties of the polymer continue to limit the wear resistance and the clinical lifespan of implanted knee and hip prosthetics containing UHMWPE components. The degree of crystallinity of UHMWPE is known to strongly influence several of its tensile mechanical properties such as Young's modulus, yield stress, strain-hardening rates, work of fracture and ultimate tensile properties. In this study, medical grade UHMWPE was subjected to four different crystallization conditions resulting in UHMWPE with a range of crystalline morphologies. Thereafter, the crystalline nanostructure was quantitatively characterized using a combination of ultra-small angle X-ray scattering and differential scanning calorimetry. Low-voltage scanning electron microscopy was employed as a supplementary technique to compare the crystalline morphology resulting from each crystallization condition. In addition, uniaxial tensile tests were performed to assess the effects of crystallization conditions on the mechanical properties of UHMWPE. This study showed that while crystallization conditions strongly influenced the morphology of UHMWPE, in most cases the mechanical properties of the material were not significantly affected.
authors.affiliation: Department of Orthopaedic Surgery, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, MRB 106, Boston, MA 02115, USA.
authors.forename: Mary Beth
authors.initials: MB
authors.lastname: Turell
authors.forename: Anuj
authors.initials: A
authors.lastname: Bellare
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D004548:Elasticity; D008422:Materials Testing / Q000379:methods*; D008968:Molecular Conformation; D036103:Nanotechnology / Q000379:methods*; D011095:Polyethylenes / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D001672:Biocompatible Materials; D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene