Direct Evaluation of Local Dynamic Viscoelastic Properties of Isotactic Polypropylene Films Based on a Dynamic μ-Beam X-ray Diffraction Method

Shuhei Nozaki, Shiori Masuda, Chao Hung Cheng, Chigusa Nagano, Kazutoshi Yokomachi, Kazutaka Kamitani, Kohki Aoyama, Hiroyasu Masunaga, Ken Kojio, Atsushi Takahara

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Abstract

The local mechanical properties of crystalline polymer were evaluated using synchrotron radiation X-ray diffraction with 10 μm lateral resolution. A nonoriented isotactic polypropylene (iPP) film with isolated spherulites in a crystallized matrix was used as a model sample. In situ wide-angle X-ray diffraction (WAXD) measurement was performed on the iPP film using a microbeam synchrotron radiation X-ray under sinusoidal strain. The lattice spacing of the crystal planes increased and decreased in response to the applied sinusoidal strain. Local dynamic viscoelastic functions (dynamic storage and loss moduli (E′ and E″)) were calculated at room temperature from the relationship between the calculated applied stress and the response strain obtained by dynamic μ-beam WAXD measurement inside and outside of the spherulites. The E′ values inside and outside of spherulite obtained from the change in spacing of the (110) plane were 1.8 and 1.1 GPa, respectively. Furthermore, the E′ value inside of spherulite obtained from the change in spacing of the (113) plane was 6.0 GPa. These values can be explained by the deformation of crystallite, which depends on the direction of crystal planes. The results obtained here revealed that synchrotron radiation X-ray diffraction measurement gives not only structural information but also the local mechanical properties of the materials E′.

Original languageEnglish
Pages (from-to)218-222
Number of pages5
JournalACS Macro Letters
Volume8
Issue number2
DOIs
Publication statusPublished - Feb 19 2019

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All Science Journal Classification (ASJC) codes

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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