Polyethylene joints

Y-aminopropyl triethoxy silane in a-Al203/polyethylene joint. Polymer Engng. Sci. 22 637 (1982). 

Tomita N, Kitakura T, Onmori N, Ikada Y, Aoyama E. Prevention of fatigue cracks in ul-trahigh molecular weight polyethylene joint components by the addition of vitamin E. J Biomed Mater Res 1999 48 474-8. 

Figure 2.8 Joint strength versus wetting constant, k2, for a series of thermosetting resin/polyethylene joints [144].

The effect of test velocity on weld performance was investigated with impact tests performed at 20 C and 1, 2 and 3.7 m/s. Over this range the dynamic effects very often overshadow the true material response and additional measurement techniques must be applied to determine dynamic fracture toughness [8]. Therefore impact strength was evaluated as the ratio of the total consumed energy and the resistant area. The quahty of fused polyethylene joints was assessed by means of the weld efficiency, cp [9], which is defined as ... 

The work presented in this paper was the result of the joint effort with the following colleagues. For the simulations on catalysis Simonetta larlori (IBM Italy), Franco Buda (Scuola NormaJe Superiore, Pisa, Italy) and Gerard van Doremaele (DSM Research) were involved. For the work on polyethylene the simulations were performed by Joost Hageman, with help from Martina Heinemann and Rob de Groot (all University of Nijmegen, The Netherlands). 

The materials used in a total joint replacement ate designed to enable the joint to function normally. The artificial components ate generally composed of a metal piece that fits closely into bone tissue. The metals ate varied and include stainless steel or alloys of cobalt, chrome, and titanium. The plastic material used in implants is a polyethylene that is extremely durable and wear-resistant. Also, a bone cement, a methacrylate, is often used to anchor the artificial joint materials into the bone. Cementiess joint replacements have mote tecentiy been developed. In these replacements, the prosthesis and the bone ate made to fit together without the need for bone cement. The implants ate press-fit into the bone. 

In 1971 a metal-backed polyethylene acetabular cup was introduced. This cup provided an eccentric socket which was replaceable, leaving the metal and replacing only the polyethylene. Because of the success of this component, metal-backed high density polyethylene (HDPE) liner is standard for prosthetic acetabular components. Research confirms that metal-backing reduces the peak stresses in the bone cement, and that HDPE forms a successfiil articulating surface for the prosthetic joint. 

Charnley, J., Total Prosthetic Replacement of the Hip Joint Using a Socket of High Density Polyethylene , Wrightington Hospital Publication No. 1 Centre for Hip Surgery, (1966)... 

Although iron pipes suffer from the same corrosion risk as steel pipelines, associated with the generation of a galvanic cell with a small anode and a large cathode, the risk is mitigated for iron pipelines because the electrical continuity is broken at every pipe joint. For this reason long-line currents are uncommon in iron lines and cathodic protection is rarely necessary. It also accounts for the ability to protect iron lines by the application of nonadherent polyethylene sleeving . 

Heat-shrink crosslinked polyethylene DIN 30672 Flame or heat gun in fieid 1-25-2-25 Utiiised for coating of field weld joints and repairs on extruded polyethylene coated pipes. Careful application required to achieve consistent bond. 

Weld joints may be coated in the field with FBE powder, utilising a portable blast cleaning/induction heating and powder application system. Alternatively joints may be provided with self-adhesive laminate tapes or heat-shrink crosslinked polyethylene sleeves. 

Repairs to the coating are made with either hot-melt polyethylene sticks or polyethylene sheet patches with mastic profiling compounds for small damaged areas. Large repair areas are best treated as for field weld joint coating, where either heat-shrink crosslinked polyethylene sleeves or cold-applied self-adhesive laminate tapes are employed. 

UNIPOL [Union Carbide Polymerization] A process for polymerizing ethylene to polyethylene, and propylene to polypropylene. It is a low-pressure, gas-phase, fluidized-bed process, in contrast to the Ziegler-Natta process, which is conducted in the liquid phase. The catalyst powder is continuously added to the bed and the granular product is continuously withdrawn. A co-monomer such as 1-butene is normally used. The polyethylene process was developed by F. J. Karol and his colleagues at Union Carbide Corporation the polypropylene process was developed jointly with the Shell Chemical Company. The development of the ethylene process started in the mid 1960s, the propylene process was first commercialized in 1983. It is currently used under license by 75 producers in 26 countries, in a total of 96 reactors with a combined capacity of over 12 million tonnes/y. It is now available through Univation, the joint licensing subsidiary of Union Carbide and Exxon Chemical. A supported metallocene catalyst is used today. 

Low pressure low density polyethylene (LDPE), 70 595 Low pressure tanks, 24 288 Low Q-state, 74 674 Low rank coal, defined, 6 828 Low resistivity joints, 23 847 Low silica zeolites, 76 833... 

These include attempts by surgeon M.N. Smith-Petersen in 1925, Robert and Jean Judet in 1938, and Dr. Edward J. Haboush in 1953. However, the first successful hip prosthesis was not developed until 1961 when Dr. Chamley made a hip prosthesis out of a high molecular weight polyethylene cup. Today, artificial hip joints are implanted in over 200,000 people each year in the USA (Ratner, 2004). 

ISO 1872-1 1993 Plastics - Polyethylene (PE) moulding and extrusion materials - Part 1 Designation system and basis for specifications ISO 1872-2 1997 Plastics - Polyethylene (PE) moulding and extrusion materials - Part 2 Preparation of test specimens and determination of properties ISO 1969 2004 Fibre ropes - Polyethylene - 3- and 4-strand ropes ISO 3458 1976 Assembled joints between fittings and polyethylene (PE) pressure pipes -Test of leakproofness under internal pressure ISO 3459 1976 Polyethylene (PE) pressure pipes - Joints assembled with mechanical fittings - Internal under-pressure test method and requirement ISO 3501 1976 Assembled joints between fittings and polyethylene (PE) pressure pipes -Test of resistance to pull out... 

ISO 3503 1976 Assembled joints between fittings and polyethylene (PE) pressure pipes -Test of leakproofness under internal pressure when subjected to bending ISO 3663 1976 Polyethylene (PE) pressure pipes and fittings, metric series - Dimensions... 

ISO 4059 1978 Polyethylene (PE) pipes - Pressure drop in mechanical pipe-jointing systems - Method of test and requirements ISO 4427 1996 Polyethylene (PE) pipes for water supply - Specifications ISO 4437 1997 Buried polyethylene (PE) pipes for the supply of gaseous fuels - Metric series - Specifications... 

ISO 8796 2004 Polyethylene PE 32 and PE 40 pipes for irrigation laterals - Susceptibility to environmental stress cracking induced by insert-type fittings - Test method and requirements ISO 9625 1993 Mechanical joint fittings for use with polyethylene pressure pipes for irrigation purposes... 

ISO/TR 11647 1996 Fusion compatibility of polyethylene (PE) pipes and fittings ISO 12176-1 1998 Plastics pipes and fittings - Equipment for fusion jointing polyethylene systems - Part 1 Butt fusion... 

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