- 學位論文
聚醯亞胺與陶瓷複合薄膜之製備及其特性之研究
Preparation and Properties of Polyimide / Ceramic Composite Films
摘要
本研究分為三個部份來討論，第一部分為探討三種不同結構的聚醯亞胺，在電性及熱性方面有何不同。本實驗分別採用Pyromellitic dianhydride（PMDA）、4,4-Oxydiphthalic anhydride（ODPA）、3,3’,4,4’-Benzophenone tetracarboxilic dianhydride （BTDA）為二酸酐單體和4,4'-Oxydianiline（ODA）二胺單體先合成三種聚醯胺酸，經過熱熟化步驟得到聚醯亞胺。本實驗結果中，PMDA的熱穩定性為最佳（熱裂解溫度為542 ℃，玻璃轉換溫度為309 ℃），而ODPA系列的聚醯亞胺不僅熱穩定性均較其他兩系列的聚醯亞胺低，且其電阻率與介電常數也稍低，但是在常溫下測試頻率為10 kHz時，此三種不同結構的聚醯亞胺之介電常數均十分接近（約3.5），在吸水性研究上， PMDA系列的聚醯亞胺為最差，這是因為結構上較不對稱導致內部自由體積較大的緣故。 第二部份為製備低介電複合材料，目前在液晶產業中配向膜通常是以有機單體Pyromellitic dianhydride（PMDA）和4,4'-Oxydianiline （ODA）先合成聚醯胺酸，再經過熱熟化步驟，得到聚醯亞胺。本研究在合成聚醯胺酸後，將以分散劑改質過的氧化鋯無機相強制分散在聚醯胺酸有機相中，經過階段式升溫加熱後得到聚醯亞胺/氧化鋯複合薄膜。本實驗結果中，複材的介電常數和電阻率皆隨著氧化鋯量的增加而些微升高（複材在常溫下、測試頻率為10 kHz時的介電常數為3.8），而熱穩定性也較純聚醯亞胺佳（摻雜2.71 vol.％氧化鋯之聚醯亞胺複材的熱裂解溫度為550 ℃高於純聚醯亞胺的熱裂解溫度542 ℃），吸水率也大幅下降。 第三部份為製備高介電複合薄膜，目前在電容器中間的介電層仍以鈦酸鋇為主，本研究是希望能藉由聚醯亞胺的可撓性及鈦酸鋇的高介電特性來製備出可撓曲且厚度薄的高介電材料，本實驗中採用有機單體3,3’,4,4’-Benzophenone tetracarboxilic dianhydride（BTDA）和4,4'-Oxydianiline（ODA）先合成聚醯胺酸，再將鈦酸鋇粉體無機相強制分散在聚醯胺酸有機相中，混合後經過縮合反應可以得到聚醯胺酸/鈦酸鋇混合溶液。最後階段升溫的方式加熱使其脫水環化，形成聚醯亞胺/鈦酸鋇複合薄膜。本實驗結果中，複材的介電常數和電阻率（複材之介電常數可達42）均因為鈦酸鋇添加量的增加而大幅提升，且熱穩定性佳（摻雜18.75 vol.％氧化鋯之聚醯亞胺複材的熱裂解溫度為550 ℃高於純聚醯亞胺的熱裂解溫度520 ℃），吸水率也因添加量的增加而大幅降低。
並列摘要
In this study, two kinds of monomers- Pyromellitic dianhydride（PMDA）and 4,4'-Oxydianiline（ODA） were used to synthesize the precursor called polyamic acid （PAA）of polyimide（PI）. Two series of polyimide/ZrO2 and polyimide/BaTiO3 composite films with varying amounts of ZrO2 （0 ~ 2.71 vol.％）and BaTiO3 content （2.5 ~ 67.5 vol.％）were successfully prepared by the mixing method（System A）and the mixing method with the dispersion agent（System B）. Films were characterized by fourier transform infrared spectroscopy（FTIR）, X-ray diffraction（XRD）, thermo gravimetric analysis（TGA）, and differential scanning calorimetry（DSC）. XRD results confirm the ceramic particles remain unchanged in the polyimide matrix and no undesired secondary phases are present in the films. The functional group and chemical structure were characterized by FTIR spectroscopy. The mentioned peaks are the characteristic absorption of imide group shown in the FTIR spectra of the entire PI film, PI/ZrO2 hybrid and PI/BaTiO3 films. Besides, the introduction of the ZrO2 and BaTiO3 lead to a broad and strong absorption band in the range of 566 cm-1 and 542 cm-1, respectively. Their glass transition behavior and thermal stability were investigated by DSC and TGA, and the thermal decomposition temperature of these films were stable to 500 ℃, and the glass transition temperature of these films were stable to 500 ℃. The electric properties of composite material were measured by resistance analysis and dielectric constant analysis. The results indicate that glass transition temperature（Tg）and the thermal decomposition temperature（Td）of PI/Ceramic composite films increased with increasing ceramic content. Therefore, the dielectric constant of PI/Ceramic composite material increased with increasing ceramic content.