UHMWPE uses

Sample Preparation. The UHMWPE used in this study was a HiFax 1900 (Himont, Inc.) with an average molecular weight of 2-8 x 10. The UHMWPE was added to paraffin oil to concentrations from 2 to 5% w/w. To avoid polymer degradation at high temperatures, the polymer was stabilized with approximately 0.5% of BHT antioxidant. The mixture was stirred at 150 C. A solution was obtained that was clear until it was cooled to about 120 C when it became opaque and transformed into a gel-like or pseudo-gel. 

Enhancing the wear resistance of polymers (e.g., ultra-high-molecular-weight polyethylene-UHMWPE-used for in vivo implants, such as artificial hip joints). ... 

O K. MURATOGLU, D.O.O CONNOR, C.R. BRAGDON, J. DELANEY, M. JASTY, W.H. HARIS, E. MERRILL, P. VENUGOPALAN, Gradient crosslinking of UHMWPE using irradiation in molten state for total joint arthroplasty , Biomaterials, 23 (2002)717-724... 

Tivar . [Ifoly-Hi Menasha] UHMWPE used in psqrer industry (pulping and fin-... 

Bergstrom, J. S., Rimnac, C. M., and Kurtz, S. M., Prediction of Multiaxial Behavior for Conventional and Highly Crosslinked UHMWPE using a Hybrid Constitutive Model, Biomaterials, 24 1365-1380 (2003)... 

Carbon fibers have been incorporated in the high density polyethylene used in total knee replacements (Figure 41.5). The standard ultra high molecular weight polyethylene (UHMWPE) used in these implants... 

Edidin A.A., and S.M. Kurtz. 2001. Development and validation of the small punch test for UHMWPE used in total joint replacements. In Functional biomaterials. N. Katsube, W. Soboyejo, and M. Sacks. Eds. Winterthur, Switzerland Trans Tech Publications. 

Kurtz S.M., C. Cooper, R. Siskey, and N. Hubbard. 2003. Effects of dose rate and thermal treatment on the physical and mechanical properties of highly crosslinked UHMWPE used in total joint replacements. Transactions of the 49th Orthopedic... 

Table 12.1 summarizes some of the tests discussed in the FDA guidance document Data Requirements for Ultra-High Molecular Weight Polyethylene (UHMWPE) used in Orthopedic Devices (FDA 1995). If the new polyetirylene has almost identical properties to a polyethylene already on the market after stage 1 testing, no further testing may be required. If it does differ in properties from an existing... 

Kurtz S.M., C.W. Jewett, J.S. Bergstrom, et al. 2003. Miniature specimen shear punch test for UHMWPE used in total joint replacements. Biomaterials 23 1907-1919. 

In summary, there are a number of different constitutive models that can be used to predict different aspects of UHMWPE behavior. The most advanced of the currently available models is the HM, which has been shovm to be able to predict the behavior of both conventional and highly crosslinked UHMWPE used in total joint replacements. The HM is currently limited to isothermal deformation histories, although research is ongoing to enable to arbitrary thermomechanical deformation states. In addition, fatigue, fracture, and wear are targets for current and future studies. 

Bergstrom J.S., C.M. Rimnac, and S.M. Kurtz. 2003. Prediction of multiaxial behavior for conventional and highly crosslinked UHMWPE using a hybrid constitutive model. Biomaterials 24 1365-1380. 

The mechanical properties at the surface of the UHMWPE will also play an important role in determining the tribological behavior. The UHMWPE pins were produced and machined in the same way and y-irradiated with the same dose before use to ensure the same surface properties as UHMWPE used in artificial joints. It can, therefore, be assumed that there is little variation in the mechanical properties. However, small variations in the shear strength at the surface may be sufficient to determine whether lumpy transfer of poljoner occurs or a smooth transfer fOm is formed. If the transfer film was thinner than 10 nm it would not be detected in the fluorescence imaging but may have been formed in those cases where the friction coefficient dropped to a lower value. 

The wear rates shown for UHMWPE used for hip joint replacement are somewhat in conflict. 

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]. 

F2759-11 Standard guide for assessment of the Ultra High Molecular Weight Polyethylene (UHMWPE) used in Orthopedic and Spinal Devices... 

Figure 4.20. A representative TEM image of a chemically cross linked UHMWPE, used as an implant material in artificial joints, prepared by staining with chlorosulfonic acid and poststaining in 2% uranyl acetate [261], shows numerous lamellae. (From Kurtz [261] used with permission.)...

The ultra-high molecular weight polyethylene (UHMWPE) used in orthopedic applications is a type of polymer generally classified as a linear homopolymer. Our first task is to explain what is meant by all of these terms. Before proceeding to a definition of UHMWPE, one needs to first understand what constitutes a linear homopolymer. 

During the 1990s, the packaging and sterilization of UHMWPE was a controversial topic. As recently as 1995, UHMWPE was typically sterilized with a nominal dose of 25 to 40kGy of gamma radiation in the presence of air. By 1998, all of the major orthopedic manufacturers in the United States were either sterilizing UHMWPE using... 

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