本文選題：聚苯并咪唑　切入點：二氧化鈦　出處：《北京化工大學》2015年碩士論文

【摘要】：隨著現代工業(yè)的發(fā)展,對質量輕和大容量的儲能材料需求越來越迫切。高介電性聚合物基復合材料同時具備介電性能優(yōu)異,質量輕,易加工等優(yōu)點,對儲能材料的發(fā)展具有重要意義,然而目前廣泛研究的高介電性聚合物基復合材料所用聚合物基底通常耐熱性較差,不能在高溫下長期使用。本文選擇具有高玻璃化轉變溫度的聚苯并咪唑(PBI)作為聚合物基體,制備耐高溫的高介電聚合物基復合材料,分別制備了PBI/TiO2復合膜,PBI/Gn-TiO2復合膜及PBI/Ag@TiO2復合膜三個系列的介電復合膜材料,并研究了其微觀結構、結晶性能、熱穩(wěn)定性和介電性能等性質。具體研究內容如下：(1) 采用溶液澆鑄法制備PBI/TiO2復合膜并研究其性能：通過微波輔助的溶液縮聚法制備聚苯并咪唑,通過改性的溶膠凝膠法制備金紅石型的二氧化鈦粉末,并用KH550對其進行改性得到kTiO2,將納米Ti02和kTiO2分別用溶液共混法與PBI復合,制備得到不同TiO2和不同kTiO2含量的復合膜。納米TiO2在復合膜中分布均勻,且復合膜均表現出優(yōu)異的熱穩(wěn)定性,在450℃下失重量很少。隨著TiO2含量的增大,復合膜的介電常數先降低后增大,在1000Hz加入量為20wt%時達到20.5。隨著kTiO2添加量的增大,復合膜的介電常數出現下降趨勢,但其頻率穩(wěn)定性得到明顯提高。復合膜的介電損耗均保持在較低的水平。(2) 采用溶液澆鑄法制備PBI/Gn-TiO2復合膜并研究其性能：通過改進的Hummer法制備氧化石墨,并采用一步溶劑熱法制備石墨烯負載納米二氧化鈦(Gn-TiO2),將Gn-TiO2與PBI復合,制備一系列不同Gn-TiO2添加量的復合膜。Gn-TiO2在復合膜中分布均勻,且復合膜熱穩(wěn)定性良好,在500℃下失重量很少。在Gn-TiO2摻雜量為3wt%時,復合膜的介電常數和介電損耗均出現了較為明顯的增長,在該添加量時達到滲流閾值。(3) 采用溶液澆鑄法制備PBI/Ag@TiO2復合膜并研究其性能：通過步還原水解法制備Ag@TiO2,將其與PBI進行復合,制備了PBI/Ag@TiO2復合膜材料。Ag@TiO2在聚合物基體中分布均勻,且形成網狀結構。復合膜熱穩(wěn)定性能良好,在500℃下失重量很少。室溫下隨著Ag@TiO2含量的增加,復合膜的介電常數出現先下降后升高的趨勢。在Ag@TiO2的添加量達到50%時,復合膜的介電常數達到最大值。1000Hz下,PBI/Ag@TiO2復合膜的介電常數和介電損耗在60℃以下有輕微的提高,當溫度大于60℃時,介電常數和介電損耗隨溫度顯著增大。
[Abstract]:With the development of modern industry, the demand for energy storage materials of light weight and large capacity is more and more urgent. High dielectric polymer matrix composites have the advantages of excellent dielectric properties, light weight, easy processing and so on. It is of great significance for the development of energy storage materials. However, the polymer substrates used in high dielectric polymer matrix composites, which are widely studied at present, are usually of poor heat resistance. Polybenzimidazole (PBI) with high glass transition temperature was selected as the polymer matrix to prepare high temperature resistant high dielectric polymer matrix composites. Three series of dielectric composite membranes, PBI/TiO2 / Gn-TiO _ 2 composite membrane and PBI/Ag@TiO2 composite membrane, were prepared, and their microstructure and crystallization properties were studied. The main contents are as follows: (1) PBI/TiO2 composite films were prepared by solution casting method and their properties were studied: polybenzimidazole was prepared by microwave-assisted solution Polycondensation. Rutile titanium dioxide powder was prepared by modified sol-gel method and modified by KH550 to obtain kTiO _ 2. The nano-sized Ti02 and kTiO2 were blended with PBI by solution blending method, respectively. The composite films with different TiO2 and different kTiO2 content were prepared. The TiO2 nanoparticles were uniformly distributed in the composite films and showed excellent thermal stability. The weight loss was very small at 450 鈩，

本文編號：1692127