Highly cross-linked UHMWPE

H. Schmotzer, Method for producing implant parts from highly cross-linked uhmwpe and implant parts for human medicine, US Patent 7 364 685, assigned to Plus Orthopedics AG (Rotkreuz, CH), April 29, 2008. 

Testing using the shear punch apparatus of convenhonal and highly cross-linked UHMWPE strongly suggested the representative behaviors in shear... 

Despite the promising results presented by other antioxidants, the main oxidation stabilizers of choice are sterically hindered phenols, among which Vitamin E and Irganox (1010, 1035, 1076) stand out. These antioxidants have been shown to be more effective in radiative processes [80, 81]. Also, advances on the mechanisms of stabilization in polymer processing have shown that vitamin E is more efficient compared to other commercial additives [82,83]. Tocopherol compounds were proposed as stabilizers for polyolefins in the 1980s [84] and currently, they are the best alternative for the oxidative stabilization of highly cross-linked UHMWPEs. 

Figure 2.7 Decomposition curves corresponding to the beginning of the TG experiment for various stabilixed highly cross-linked UHMWPEs. Adapted from Ref [76].

Oral E, Malhi A, Wannomae K, Muratoglu O. Highly cross-linked UHMWPE with improved fatigue resistance for total joint arthroplasty. Journal of Arthroplasty (Winner of the 2006 HAP Paul Award). In press. 

Edidin A.A., L. Pruitt, C.W. Jewett, et al. 1999. Plasticity-induced damage layer is a precursor to wear in radiation- cross-linked UHMWPE acetabular components for total hip replacement. Ultra-high-molecular-weight polyethylene. J Arthroplasty 14 616-627. 

Recently Nitto Denko developed a battery separator made by a wet process that had high puncture strength and high heat rupture resistance. They used a polyolefin resin with a high-molecular-weight rubber as its main component materials and cross-linked through oxidation in air. The melt rupture temperature, as measured by thermomechanical analysis, was over 200°C in this material. They also tried cross-linking UHMWPE with electron-beam and ultraviolet irradiation, but this had the... 

The fixation of the impiant parts in the bone may be achieved by self-curing polymer resins (bone cements) such as PMMA (see above) or via direct integration of micro- or macroporous implant surfaces into the host bone. The UHMWPE used for knee and hip joints is usually highly cross-linked [17]. 

Polyethylene (PE) high-density (HOPE), low density (LDPE), hnear low density (LLDPE), ultra high molecular weight (UHMWPE), cross linked (XLPE), and polyethylene foam Ethylene copolymers ethylene-vinyl acetate (EVA), ionomers Polypropylene (PP)... 

Oral E, Godleski Beckos C, Malhi A, Muratoglu O. The effects of high dose irradiation on the cross-linking of vitamin E-blended UHMWPE. Biomaterials. In press. 

J. Fu, B.N. Doshi, E. Oral, O.K. Muratoglu. High temperature melted, radiation cross-linked, vitamin E stabilized oxidation resistant UHMWPE with low wear and high impact strength. Polymer 54(1), 199-209, 8 January (2013). 

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