Polymorphism in Sheared Isotactic Polypropylene Containing Nucleant Particles

Authors

  • Andrew William Phillips,

    Corresponding author
    1. Formerly at Monash University, now at Maritime Platforms Division, Defence Science and Technology Organisation (DSTO), 506 Lorimer Street, Fishermans Bend, Victoria 3207, Australia
    • Formerly at Monash University, now at Maritime Platforms Division, Defence Science and Technology Organisation (DSTO), 506 Lorimer Street, Fishermans Bend, Victoria 3207, Australia

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  • Amita Bhatia,

    1. Department of Materials Engineering, Cooperative Research Centre for Polymers, Monash University, Clayton, Victoria 3800, Australia
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  • Peng-wei Zhu,

    1. Department of Materials Engineering, Cooperative Research Centre for Polymers, Monash University, Clayton, Victoria 3800, Australia
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  • Graham Edward

    1. Department of Materials Engineering, Cooperative Research Centre for Polymers, Monash University, Clayton, Victoria 3800, Australia
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Abstract

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.

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