Ultra High Molecular Weight Polyethylene UHMWPE

12 Ultra High Molecular Weight Polyethylene (UHMWPE) 

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

Ultra high molecular weight polyethylene (UHMWPE)... 

H.L. Stein, "Ultra high molecular weight polyethylene (UHMWPE)," in M.M. Gauthier, ed., Engineered Materials Handbook, Vol. 2, Engi-... 

Ultra-high molecular weight polyethylene (UHMWPE) has been used in orthopaedic prosthetic surgery for many years due to its excellent mechanical properties and frictional resistance. A large number of studies on both retrieved prostheses and raw material have, however, been necessary in order to understand and prevent degradation of the prostheses. The shape of the prostheses and the compression moulded blocks from which they are cut is usually not suitable for examination. In a number of studies microtomy has therefore been used in order to produce pieces suitable for further studies [112, 113, 114, 115, 116, 117, 118, 119, 120]. However, very often when microtomy is used, it is without any consideration of the fact that the process... 

Figure 10.32 TG curves of hydroxyapatite (HA)-ultra-high molecular weight polyethylene (UHMWPE) composites with different content HA particles. The legends indicate the nominal volume fraction of HA in the UHMWPE matrix.

Valenza, A. Visco, A.M. Torrisi, L. Campo, N. Characterization of ultra-high-molecular-weight polyethylene (UHMWPE) modified by ion implantation. Polymer 2004, 45, 1707-1715. 

Greatest drawability was studied for blend films with branched low molecular weight polyethylene (B-LMWPE) and ultra-high molecular weight polyethylene (UHMWPE) prepared by gelation/crystallization from solutions. The morphology of B-LMWPE-UHMWPE dry gel film was determined by solid-... 

Blends of LLDPE/PP = 50 50, with or without compatibilizing ethylene-propylene copolymer, EPR, were studied by Dumouhn et al. [1984]. In spite of the expected immiscibihty, the blends showed additivity of properties with good superposition of the stress growth functions in shear and elongation, as well as with the zero deformation rate Trouton ratio, Rj, = 1. In earlier work, blends of medium density PE (MDPE) with small quantities of ultra-high molecular weight polyethylene (UHMWPE) were studied in shear and extension. Again, SH and Rj, = 1 were observed. 

Table 11.10. Melting and crystallization enthalpies of ultra-high molecular weight polyethylene (UHMWPE) and normal molecular weight polyethylene (NMWPE) blends [Minkova and Mihailov, 1990]...

Two sets of experiments were performed. In the first set, three polymers with very different mechanical properties were chosen to determine their response to this experiment. Polycarbonate PC, rigid polyvinyl chloride PVC, and ultra-high molecular weight polyethylene UHMWPE, were loaded with 10, 8.5, and 7.2 N and tested at 0.04 m/s sliding speed. In these tests, the friction force was continuously... 

When polytetrafluoroethylene (PTFE) was Introduced in the early 1960 s the life of total replacement hip joints was limited to about three years by the poor wear characteristics of the polymer. When ultra-high molecular weight polyethylene (UHMWPE) replaced PTFE, the rate of penetration of the metallic component into the polymeric component was reduced to such an extent that loosening emerged as a major aspect of prosthetic life. There is, nevertheless, a need to pursue studies of the wear of prosthetic materials to facilitate the development of satisfactory materials which can be used with confidence in long-life prostheses. 

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... 

The blood bag case study illustrates the use of polymeric film as a flexible container. It considers the permeability of polymers, plus processes for fabricating plastics film. Plasticised PVC has dominated the market for years, but there could be a changeover to flexible polyolefin films. The case study on replacement joints for implanting in the body illustrates wear and the effects of wear debris. Research continues on improving the wear resistance of the ultra high molecular weight polyethylene (UHMWPE) and mitigating the effects of sterilisation on the implant properties. 

Ultra-high molecular weight polyethylene (UHMWPE) can also be considered as sncb an intentional additive, becanse it can be nsed for scratch-resistant coatings, which can... 

Copolymer ethylene-dimethyl-aminoethyl methacrylate (EDAM) with 3.9% DAM side groups and ultra-high molecular weight polyethylene (UHMWPE) were blended in decalin solvent. The hot homogenized solution was poured into an aluminum tray to form gels and the decalin was allowed to evaporate from the... 

The focus in this chapter will be on the two main polyolefin polymers, namely polyethylene (PE) and polypropylene (PP). The latter especially has established itself as a very versatile fiber with unique applications in the textile and nonwoven industry. Polyethylene, on the other hand, has not been widely used as a fiber compared to other synthetic polymers such as PET, PP, and nylon, due in part to its low melting point. This chapter will, however, discuss ultra-high molecular weight polyethylene (UHMWPE) fiber that given its success and uniqueness in the synthetic fiber industry. 

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