溶凝膠法製備聚亞醯胺-有機矽酸鹽複合材料及其性質研究

Abstract

本實驗以溶-凝膠法（sol-gel process）製備具有低介電係數特性的聚亞醯胺-有機矽酸鹽複合材料。紅外光譜分析（FTIR）顯示，含聚醯胺酸的原料經熟化處理後可形成含有機矽酸鹽微粒的聚亞醯胺複合結構；29Si CP MAS固態核磁共振、Mapping、SEM與TEM結果顯示有機矽酸鹽為非緻密結構且可以數奈米尺寸之球狀顆粒均勻分散於聚亞醯胺基材中；熱分析實驗顯示複合材料於氮氣氣氛下測得之裂解溫度皆高於540℃，於空氣氣氛下測得之裂解溫度皆高於520℃，因此聚亞醯胺-有機矽酸鹽複合材料具有優良熱穩定與抗氧化性質。本實驗電性結果顯示：（I）Class 3與Class 4之複合材料系統應有空孔結構；（II）介電係數降低與否主要和有機矽酸鹽之生成環境、添加量和發生相分離程度有關，而與混合物反應時間關係不大；（III）聚亞醯胺-有機矽酸鹽複合材料於1.5 MV/cm電場下皆未崩潰，電阻係數皆大於5×1014 W×cm；（IV）導入（-CH3）官能基對複合材料整體吸水性有抑制效果。 實驗結果顯示，Class 4試片於理想矽莫耳百分比含量為80，反應時間為6小時時可獲得一有機矽酸鹽以5 nm奈米級尺寸球狀顆粒均勻分散之複合材料，此時擁有最低的介電係數（2.201）、於1.5 MV/cm電場之作用下仍未崩潰、高電阻係數（2.316×1015 W×cm），和對吸水性有抑制效果等優異電氣性質，同時擁有於氮氣氣氛下所測得之高裂解溫度（594℃）和空氣氣氛下所測得之高抗氧化性（570℃）性質。

Sol-gel process was applied to prepare the low dielectric polyimide（PI）- organosilicate hybrids and their physical properties were investigated. The FTIR results confirmed that the hybrid precursors might transform into polyimides containing finely dispersed organosilicate particles by appropriate curing treatment. The organosilicates were not dense structures and can dispersed with the size of several nm in the PI matrix, as is reasonably inferred from the 29Si CP MAS solid NMR、Si Mapping、SEM and TEM results. All hybrid specimens exhibited excellent thermal stability that they had decomposition temperatures higher than 540℃ in N2 atmosphere and higher than 520℃ in air atmosphere, as indicated from the thermal analysis. Electrical measurements indicated that：（I）Class 3 and Class 4 hybrids might have the structures similar in xerogel；（II）Reaction ambient, addition amount and degree of phase separation of organosilicates affected the dielectric constant of the hybrids；（III）No breakdown of the hybrids at the electric field strength as high as 1.5MV/cm and the resistivities were greater than 5×1014 W×cm；（IV）Introduction of the（-CH3）functional group to organosilicates must suppress the water absorption of hybrids. The best dielectric constant value（2.201）was observed in Class 4 hybrids containing organosilicates about 5 nm in diameter. It exhibited high oxidiation resistanc（570℃）, high decomposed temperature（594℃）, high electrical resistivity（2.316×1015 W×cm）, and no breakdown at the electric field of 1.5 MV/cm when containing 80 mol.% of Si and reacting for 6 hours.