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Negative pressure effects during the isothermal crystallization of isotactic poly(propylene) studied by light and atomic force microscopy
Author(s) -
Thomann Ralf,
Wang Chun,
Kressler Jörg,
Mülhaupt Rolf
Publication year - 1996
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1996.021970326
Subject(s) - tacticity , materials science , crystallization , isothermal process , optical microscope , atomic force microscopy , microscopy , composite material , polymer chemistry , optics , chemical engineering , thermodynamics , polymer , nanotechnology , polymerization , scanning electron microscope , physics , engineering
The formation of holes during the late stage of the isothermal crystallization in thin films of isotactic poly(propylene) between two cover glasses was observed by light microscopy and atomic force microscopy. This behavior can be described consistently by the well‐known negative pressure effect. Light microscopy reveals the simultaneous and sudden occurrence of a large number of small holes at the liquid‐solid interface after the liquid in front of the spherulites is completely confined by other spherulites for a certain time interval. In exceptional cases only a few holes appear and finally large cavities are formed. Atomic force microscopy measurements carried out in the height mode are able to prove the hole formation in front of the spherulites. Furthermore, a substantial thinning of the two‐dimensional spherulites in thin films can be observed prior to the hole formation.