US4587163B1 - - Google Patents
Abstract
Abstract An isotropic semicrystalline morphology of ultra-high-molecular-weight polyethylene and a method of making it. An original powder stock or a partially fused, melt-crystallized stock having a granular memory, is heated to a temperature at which the stock fuses completely to form a homogeneous melt which loses memory of the granular structure of the original stock. The resultant melt is cooled to ambient temperatures under compression to provide a novel homogeneous isotropic semicrystalline morphology. An anisotropic morphology of ultra-high-molecular-weight polyethylene may then be made by solid-state deforming that semicrystalline morphology at a temperature near but below its crystalline melting point at a deformation ratio of about 5 to 8.
Inventors
- 👤 E Zachariades Anagnostis
Bibliographic Details
Claims Analysis
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1993-04-02 | 1993-10-02 | 1994-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-02 | 1997-10-02 | 1998-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-02 | 2001-10-02 | 2002-04-03 | $7700.00 | Window Closed / Lapsed |