Memory effect of locally ordered α-phase in the melting and phase transformation behavior of β-isotactic polypropylene

Kilwon Cho, D. Nabi Saheb, Hoichang Yang, Byoung Il Kang, Joonkyung Kim, Sang-Soo Lee

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66 Citations (Scopus)

Abstract

Structural changes in β-isotactic polypropylene (β-iPP) during the heating were studied by means of differential scanning calorimetry and real-time in situ X-ray diffraction using a synchrotron source. Crystalline phase transformation and the memory effect caused by residual nuclei of α-iPP were observed during the heating of β-iPP. The memory effect observed in β-iPP during heating and crystallization is believed to be due to the existence of locally ordered α-from in the melt. The effect of local α-form order was probed by studying the behavior under heating of samples with a range of thermal histories. Samples were heated above the equilibrium melting temperature of iPP to remove all residual local order and the memory effect associated with this local order. The samples crystallized isothermally at different temperatures exhibited a significantly different melting and phase transformation behavior during heating. β-iPP is found to be an excellent material for the study of polymorphism, phase transformations, and characteristic memory effects in semicrystalline polymers.

Original languageEnglish
Pages (from-to)4053-4059
Number of pages7
JournalPolymer
Volume44
Issue number14
DOIs
Publication statusPublished - 2003 Jun 13

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Keywords

  • β-Isotactic polypropylene
  • Memory effect
  • Phase transformation

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics

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