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Character of crystallization nuclei in isotactic polypropylene
Author(s) -
Rybnikář František
Publication year - 1982
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1982.070270507
Subject(s) - tacticity , crystallization , polypropylene , materials science , metastability , isothermal process , chemical engineering , talc , melting point , polymer chemistry , polymerization , composite material , thermodynamics , polymer , chemistry , organic chemistry , physics , engineering
Examination of the isothermal crystallization and the effect of melting conditions on samples of isotactic polypropylene and its composite with talc, combined with electron‐microscopic observation, has shown two types of heterogeneous nuclei effective in the crystallization process: (1) metastable nuclei, representing the unmelted crystalline phase of polypropylene, stabilized by solid heterogeneities, and operating after melting at relative low melting temperature and/or short melting time; and (2) stable crystallization nuclei, associated with solid heterogeneities, being probably catalyst residues. On the surface of these nuclei isotactic polypropylene tends to crystallize in an ordered fashion.