Cross-linked liquid crystalline polyimides with siloxane units: Their morphology and thermal diffusivity

Yu Shoji, Ryohei Ishige, Tomoya Higashihara, Junko Morikawa, Toshimasa Hashimoto, Atsushi Takahara, Junji Watanabe, Mitsuru Ueda

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19 Citations (Scopus)

Abstract

Cross-linked liquid crystalline (LC) polyimides with siloxane units have been developed as high thermally conductive materials. The relationship between their thermal diffusivities and film morphologies was investigated. The cross-linking reaction of the LC polyimides was monitored by Fourier transform infrared spectroscopy and differential scanning calorimetry. It was found that the cross-linked LC polyimides successfully maintained their LC structures at room temperature as confirmed by polarized optical microscopy and wide-angle X-ray diffraction (WAXD). The thermal diffusivity of the films in the thickness direction measured by a temperature wave analysis method increased gradually from 0.116 to 0.185 mm2 s-1 with the increasing extent of the cross-linking. In the detailed WAXD study, the obtained cross-linked LC polyimide films showed that the polymer chains vertically aligned in the thickness direction of the films, and the increase in the extent of the cross-linking expanded the areas of chain alignment. Such a chain alignment plays an important role in the phonon conduction in the thickness direction of the films.

Original languageEnglish
Pages (from-to)747-755
Number of pages9
JournalMacromolecules
Volume46
Issue number3
DOIs
Publication statusPublished - Feb 12 2013

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All Science Journal Classification (ASJC) codes

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

Cite this

Shoji, Y., Ishige, R., Higashihara, T., Morikawa, J., Hashimoto, T., Takahara, A., ... Ueda, M. (2013). Cross-linked liquid crystalline polyimides with siloxane units: Their morphology and thermal diffusivity. Macromolecules, 46(3), 747-755. https://doi.org/10.1021/ma302486s