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α‐ and β‐crystalline forms of isotactic polypropylene investigated by nanoindentation
Author(s) -
Labour Thomas,
Ferry Laurent,
Gauthier Catherine,
Hajji Philippe,
Vigier Gérard
Publication year - 1999
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/(sici)1097-4628(19991003)74:1<195::aid-app24>3.0.co;2-8
Subject(s) - tacticity , nanoindentation , materials science , polypropylene , crystallite , composite material , crystallization , optical microscope , modulus , stiffness , atomic force microscopy , spherulite (polymer physics) , polymer chemistry , polymer science , polymer , chemical engineering , scanning electron microscope , nanotechnology , polymerization , engineering , metallurgy
Under special crystallization conditions from the melt, both α‐ and β‐forms of isotactic polypropylene were produced simultaneously. The α‐ and β‐spherulites of polypropylene were differentiated under optical microscope, allowing the nanoindentation of individual spherulites of each crystallographic form. Elastic modulus and hardness of β‐spherulites were found to be 10 and 15% respectively lower than in α‐spherulites. The higher stiffness of α may be related to the particular interlocked structure with cross‐hatched lamellae, and to a lower molecular mobility in the crystallites. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 195–200, 1999