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Monoclinic phase in reactor powders of ultrahigh-molecular-weight polyethylene and its changes during compaction and monolithizationстатья Исследовательская статья
Информация о цитировании статьи получена из
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 3 ноября 2018 г.
- Авторы: Aulov V.A., Shcherbina M.A., Chvalun S.N., Makarov S.V., Kuchkina I.O., Pantyukhin A.A., Bakeev N.F., Pavlov Yu S.
- Журнал: Vysokomolekularnye Soedineniya. Ser.A Ser.B Ser.C - Kratkie Soobshcheniya
- Том: 46
- Номер: 6
- Год издания: 2004
- Издательство: Russian Academy of Sciences
- Местоположение издательства: Russian Federation
- Первая страница: 1005
- Последняя страница: 1013
- Аннотация: Reactor powders of ultrahigh-molecular-weight polyethylene not subjected to any mechanical treatment after their synthesis are shown to contain up to 50% crystallites in the monoclinic phase. During compaction, two-thirds of crystallites are transformed into the orthorhombic phase. This process is accompanied by the development of a new monoclinic phase; at 100-150 MPa, the content of this phase reaches its limiting level of ≈50%. At a constant pressure, the content of the monoclinic phase increases in proportion to the logarithm of the treatment time. Upon monolithization, the monoclinic phase of the pellets is fully transformed into the orthorhombic phase. This process is accompanied by the development of a new monoclinic phase; at ultimate plastic deformation ratios, the content of this phase is ≈20%. The resultant structure is not stable: after pressure release, the content of the monoclinic phase decreases. The rate of the transition from the monoclinic to the orthorhombic phase increases with increasing temperature, and, finally, the monoclinic phase fully disappears at 100°C. The development of the monoclinic phase is assumed to take place not in the process of compaction but immediately thereafter (once the pellet is released from pressure). During the action of pressure, bonds between reactor powder grains appear and prevent any volume relaxation after the pressure release. The stresses induced at the bonds are transferred to the crystallites; as a result, the orthorhombic phase is transformed into the monoclinic one. The relaxation character of this process is due to the involvement of amorphous regions in the polymorphous transition.
- Добавил в систему: Павлов Юрий Сергеевич