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 language | English |
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Pages (from-to) | 747-755 |
Number of pages | 9 |
Journal | Macromolecules |
Volume | 46 |
Issue number | 3 |
DOIs | |
Publication status | Published - Feb 12 2013 |
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry