scholarly journals Structure, Processing and Performance of Ultra-High Molecular Weight Polyethylene (IUPAC Technical Report). Part 1: Characterizing Molecular Weight

2021 ◽  
Author(s):  
Clive Bucknall ◽  
Volker Altstädt ◽  
Dietmar Auhl ◽  
Paul Buckley ◽  
Dirk Dijkstra ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Technical Report ◽  
And Performance ◽  
Ultra High Molecular Weight

scholarly journals Structure, processing and performance of ultra-high molecular weight polyethylene (IUPAC Technical Report). Part 3: deformation, wear and fracture

2020 ◽  
Vol 92 (9) ◽  
pp. 1503-1519
Author(s):  
Clive Bucknall ◽  
Volker Altstädt ◽  
Dietmar Auhl ◽  
Paul Buckley ◽  
Dirk Dijkstra ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Tensile Tests ◽  
Mechanical Tests ◽  
Dominant Factor ◽  
Stress Strain ◽  
Entanglement Density ◽  
Wide Range ◽  
And Performance ◽  
Ultra High Molecular Weight

AbstractThree grades of polyethylene, with weight-average relative molar masses, ${\bar{M}}_{\text{W}}$, of approximately 0.6 × 106, 5 × 106, and 9 × 106, were supplied as compression mouldings by a leading manufacturer of ultra-high molecular weight polyethylene (UHMWPE). They were code-named PE06, PE5, and PE9, respectively. Specimens cut from these mouldings were subjected to a wide range of mechanical tests at 23 °C. In tensile tests, deformation was initially elastic and dominated by crystallinity, which was highest in PE06. Beyond the yield point, entanglement density became the dominant factor, and at 40 % strain, the rising stress–strain curves for PE5 and PE9 crossed the falling PE06 curve. Fracture occurred at strains above 150 %. Differences in stress–strain behaviour between PE5 and PE9 were relatively small. A similar pattern of behaviour was observed in wear tests; wear resistance showed a marked increase when ${\bar{M}}_{\text{W}}$ was raised from 0.6 × 106 to 5 × 106, but there was no further increase when it was raised to 9 × 106. It is concluded that the unexpected similarity in behaviour between PE5 and PE9 was due to incomplete consolidation during moulding, which led to deficiencies in entanglement at grain boundaries; they were clearly visible on the surfaces of both tensile and wear specimens. Fatigue crack growth in 10 mm thick specimens was so severely affected by inadequate consolidation that it forms the basis for a separate report – Part 4 in this series.

Using Isostatic Pressing Techniques to Mold Uhmwpe

1995 ◽  
Vol 394 ◽  
Author(s):  
Joel Higgins ◽  
David Schroeder
Keyword(s):  
Molecular Weight ◽  
Quality Control ◽  
High Molecular Weight ◽  
Bearing Material ◽  
Isostatic Pressing ◽  
Manufacturing Methods ◽  
Particulate Debris ◽  
And Performance ◽  
Ultra High Molecular Weight

Ultra High Molecular Weight Polyethylene (UHMWPE) has been and is currently the standard for bearing material used in the orthopedic industry. The components are produced using a variety of manufacturing methods, many of which can have an effect on the longevity and performance of the device. Recently there has been extensive research into the causes of loosening of orthopedic devices. One area that has been targeted as a cause for loosening is reactions to particulate debris from the bearing surfaces of these appliances. As biological reactions to particulate become better understood, there has been an increased emphasis on the quality of the UHMWPE forms used for orthopedic bearing surfaces. Due to this increased awareness, various manufacturing and quality control improvements have been made throughout the industry.

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