title: Microstructure, thermooxidation and mechanical behavior of a novel highly linear, vitamin E stabilized, UHMWPE.
abstract: A novel, vitamin E-stabilized, medical grade ultra-high molecular polyethylene, MG003 (DSM Biomedical; The Netherlands), has been very recently introduced for use in total joint replacements. This homopolymer resin features average molecular weight similar to that of conventional GUR 1050 resin (5.5-6*10(6)g/mol), but a higher degree of linearity. The aim of this study was to characterize the microstructure, thermal and thermooxidation properties as well as the mechanical behavior of this novel MG003 resin before and after gamma irradiation in air to 90 kGy. For this purpose, a combination of experimental techniques were performed including differential scanning calorimetry (DSC), thermogravimetry (TG), transmission electron microscopy (TEM), X-Ray Diffraction, electron paramagnetic resonance (EPR), and uniaxial tensile tests. As-consolidated MG003 materials exhibited higher crystalline contents (~62%), transition temperatures (~140 °C), crystal thickness (~36 nm), yield stress (~25 MPa) and elastic modulus (~400 MPa) than GUR 1050 controls (55%, 136 °C, 27 nm, 19 MPa, and 353 MPa, respectively). Irradiation produced similar changes in both MG003 and GUR 1050 materials, specifically increased crystallinity (63% and 60%, respectively), crystal thickness (39 nm and 30 nm), yield stress (27 MPa and 21 MPa), but, above of all, loss of elongation to breakage (down to 442 and 469%, respectively). Thermogravimetric and EPR results suggest comparable susceptibilities to oxidation for both MG003 and GUR 1050 polyethylenes. Based on the present findings, MG003 appears as a promising alternative medical grade polyethylene and it may satisfactorily contribute to the performance of total joint replacements.
authors.affiliation: Department of Mechanical Engineering. Engineering and Architecture School, Universidad de Zaragoza, E-50018, Zaragoza, Spain. fjmedel@unizar.es
authors.forename: F J
authors.initials: FJ
authors.lastname: Medel
authors.affiliation: Department of Materials Science and Technology, Instituto de Investigaciones en Ingeniería de Aragón, I3A, Universidad de Zaragoza, E-50018, Zaragoza, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Martínez-Morlanes
authors.affiliation: Instituto Ciencia de Materiales de Aragón, ICMA, Universidad de Zaragoza-CSIC, E-50018, Zaragoza, Spain.
authors.forename: P J
authors.initials: PJ
authors.lastname: Alonso
authors.affiliation: Instituto Ciencia de Materiales de Aragón, ICMA, Universidad de Zaragoza-CSIC, E-50018, Zaragoza, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Rubín
authors.affiliation: Department of Materials Science and Technology, Instituto de Investigaciones en Ingeniería de Aragón, I3A, Universidad de Zaragoza, E-50018, Zaragoza, Spain.
authors.forename: F J
authors.initials: FJ
authors.lastname: Pascual
authors.affiliation: Instituto Ciencia de Materiales de Aragón, ICMA, Universidad de Zaragoza-CSIC, E-50018, Zaragoza, Spain; Department of Materials Science and Technology, Instituto de Investigaciones en Ingeniería de Aragón, I3A, Universidad de Zaragoza, E-50018, Zaragoza, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Puértolas
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D055119:Elastic Modulus; D004578:Electron Spin Resonance Spectroscopy; D005609:Free Radicals / Q000737:chemistry; D005720:Gamma Rays; D046529:Microscopy, Electron, Transmission; D010084:Oxidation-Reduction; D011095:Polyethylenes / Q000737:chemistry*; D013314:Stress, Mechanical; D013718:Tensile Strength; D013818:Thermogravimetry; D044366:Transition Temperature; D014810:Vitamin E / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D000180:Acrylic Resins; D005609:Free Radicals; C477624:GUR 1050 resin; D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene; D014810:Vitamin E