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Polymorphism in Sheared Isotactic Polypropylene Containing Nucleant Particles
Author(s) -
Phillips Andrew William,
Bhatia Amita,
Zhu Pengwei,
Edward Graham
Publication year - 2013
Publication title -
macromolecular materials and engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 96
eISSN - 1439-2054
pISSN - 1438-7492
DOI - 10.1002/mame.201200199
Subject(s) - tacticity , materials science , nucleation , crystallization , polymorphism (computer science) , shear flow , composite material , shear (geology) , polypropylene , chemical engineering , thermodynamics , polymer , polymerization , biochemistry , chemistry , physics , gene , genotype , engineering
This study explored the combined influence of shear flow and nucleating agents on isotactic polypropylene (iPP) crystallisation. The study showed that oriented α‐iPP crystals were not necessary to form β‐iPP crystals, contrary to the accepted view that the surface of oriented α‐iPP crystals provides nucleation sites for an α‐iPP to β‐iPP growth transition. Instead it was proposed that flow‐induced mesomorphic point‐like nuclei preferentially nucleates β‐iPP. The combined effect of shear flow and nucleant was found to promote γ‐iPP crystals. The surprising γ‐iPP nucleation effect was explained by the high density of flow‐induced and heterogeneous nuclei present at the start of crystallisation.