High molecular polyethylene

Thermal destruction of low-pressure polyethylene with molecular weight of 34,800 and of high-pressure polyethylene is completely retarded by potassium hydroxide. The molecular weight of high-molecular polyethylene decreases by a factor of 1.8, and without an... 

Large yields of polymer seem to be obtained only when polymerization proceeds on the outer catalyst surface, because the transport of high molecular polyethylene from catalyst pores is impossible (112). The working part of the specific surface of the catalyst can be expected to increase with diminishing strength of links between catalyst particles (112). Therefore, to obtain a highly active catalyst a support with large pore volume should be used (e.g. silica with pore volume >1.5 cm8/g). 

Tilting disc Leaflet Delrin Pyrolytic carbon (carbon deposited on graphite substrate) ultra high molecular polyethylene (UHMPE)... 

Verfahren zur Herstellung von hochmolekularen Polyathylenen Process for Preparing High-Molecular Polyethylenes Karl Ziegler, Heinz Breil, Erhard Holzkamp, Heinz Martin Filed 18 November 1953, Published 14 April 1960... 

The crystalline fraction, C, is correlated with the chain length. High molecular polyethylene (HMPE) has a crystalline... 

Streicher RM. Ultra-high-molecular polyethylene as material for hip-joint cups. Stuttgart Georg Thieme Verlag 1986. 

For special parts, preference is given to using plastic, for the filter grids and the fdtrate pipes, for example polypropylene. The control and near plates are normally made of high-molecular polyethylene. These parts can optionally also be supphed in other materials, for example steel, stainless steel or cast iron. 

Turning to analogy about mediiuns with crystalline morphology of polymer matrices, let us note, that semicrystalline polymers (e.g., high-molecular polyethylenes) large strains, making 1000 2000%, are realized owing to... 

Beloshenko, V. A., Kozlov, G. V., Slobodina, V. G., Prut, E. U., Grinev, V. G. (1995). Thermal Shrinkage of Extrudates of Ultra-High-Molecular Polyethylene and Polymerization-Filled Compositions on its Basis. Vysokomolek. Soed. B, 37(6), 1089-1092. 

Kozlov, G. V, Beloshenko, V. A., Aloev, V. Z., Varyukhin, V. N. (2000). Microhardness of Ultra-High-Molecular Polyethylene and Componor on its Basis Produces by Solid-Phase Extrusion Method. Fiziko-Khimicheskaya Mekhanika Materialov, 36(3), 98-101. 

The orifice angle of the cone can signiflcantly influence the flow anomalies that are frequently found with high molecular polyethylene (PE). In such cases, changing the melt temperature has little effect. Computer programs are available to calculate the distribution of shear rate in the extrusion flow channel. It is important to ensure that the critical shear rate occurs near the die exit resp. is confined to as narrow a region as possible. With the accumulator head, the effects of flow anomahes can be influenced by the extrusion velocity. To achieve the shortest cycle times with continuous extrusion, the plastic usually exits from the orifice at close to critical shear rate. 

Garcia RM, Kraay Ml, Messerschmitt PJ, Golberg VM, Rimnac CM. Analysis of Retrieved Ultra High Molecular Polyethylene Tibial Components From Rotating-Platform Total Knee Arthroplasty. J Arthroplasty. 2009 24 131-8. 

Figure 6.33 The dependences of the microhardness on the extra energy localisation regions dimension D for EP-1 (1), EP-3 (2), polyarylate (3), ultra-high molecular polyethylene (UHMPE) (4) and Componor UHMPE-bauxite (5) [87]...

The introduction of bauxite as a filler in ultra-high molecular polyethylene (UHMPE) results in two-fold growth of the extra energy localisation regions dimension from D 4 (UHMPE) to Df 8 (UHMPE-bauxite). In addition the microhardness increases approximately twice (Figure 6.33). 

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