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Study of cryostructuring of polymer systems: 28. Physicochemical properties and morphology of poly(vinyl alcohol) cryogels formed by multiple freezing-thawingстатья
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
- Авторы: Lozinsky V.I., Damshkaln L.G., Kurochkin I.N., Kurochkin I.I.
- Журнал: Colloid Journal
- Том: 70
- Номер: 2
- Год издания: 2008
- Издательство: Pleiades Publishing, Ltd
- Местоположение издательства: Road Town, United Kingdom
- Первая страница: 189
- Последняя страница: 198
- DOI: 10.1007/s10595-008-2011-0
- Аннотация: Macroporous viscoelastic poly(vinyl alcohol) (PVA) cryogels are prepared from aqueous concentrated (80-120 g/l) PVA solutions subjected to 1-5 cycles of cryogenic treatment (freezing at -20 degrees C for 19 h and subsequent thawing at a rate of 0.3 degrees C/min). Shear moduli and fusion temperatures of corresponding samples are determined and the structure of thin sections is studied by optical microscopy with subsequent processing and analysis of images obtained. The previously described effect of a substantial increase in the rigidity and thermal stability of PVA cryogels resulted from the repeated freezing-thawing cycles is confirmed. The largest (jumpwise) changes in the physicochemical characteristics of such gels and their macroporous morphology take place after the second cycle of cryogenic treatment. Moreover, depending on the PVA concentration in the initial solution, the mean cross section of micropores increases by a factor of 2-3 and the total porosity of cryogel rises by a factor of 1.5-2; i.e., the imperfection of material increases. Nevertheless, this negative (from view-point of the integral properties of cryogel) effect is completely overpowered by processes of additional structuring, which result in the strengthening of polymer phase proceeding during the repeated freezing-thawing cycles.
- Добавил в систему: Курочкин Илья Николаевич