CEC基高介電常數(shù)復(fù)合材料的制備與研究
發(fā)布時間：2018-09-06 07:52
【摘要】：伴隨著電子集成技術(shù)的發(fā)展,開發(fā)體積更小、性能更優(yōu)異及加工更容易的電容器成為新的趨勢,這就要求其中的電介質(zhì)材料具有更高的介電常數(shù)。傳統(tǒng)的陶瓷基介電材料雖然介電常數(shù)高,但其介電損耗高,加工溫度高,韌性差,密度大。高分子聚合物材料具有輕質(zhì)、低成本、易加工、機械性能良好等優(yōu)點,但介電常數(shù)較低。通過納米復(fù)合技術(shù)制備聚合物/納米填料復(fù)合材料,在保持聚合物輕質(zhì)、易加工及柔韌性的同時,具備較高的介電常數(shù),是獲得性能優(yōu)良的高介電材料的重要途徑。本文以本征介電常數(shù)高的氰乙基纖維素(CEC)為基體,以具有良好導(dǎo)電性能的石墨烯為填料,制備了一系列復(fù)合材料,表征了其性能,最終獲得了高介電常數(shù)的CEC基復(fù)合材料。以纖維素為原料,以丙烯腈為醚化劑,采用溶媒法合成出高取代度的CEC,通過對堿化濃度、反應(yīng)時間、反應(yīng)溫度等因素的研究,優(yōu)化合成方法,實現(xiàn)了CEC取代度的可控。利用改進的Hummers法制備氧化石墨烯,以苯肼為還原劑,在CEC基體溶液中原位還原制備了石墨烯/CEC高介電常數(shù)材料,結(jié)果表明,隨著石墨烯含量的增大,復(fù)合材料的介電常數(shù)增大,當(dāng)石墨烯含量為0.5 wt.%時,100 Hz下的介電常數(shù)達到了84。同時研究還發(fā)現(xiàn),苯肼不能完全還原氧化石墨烯。采用非溶劑法和溶膠-凝膠伴隨相分離兩種方法制備了CEC的多孔塊體材料,研究了其孔徑及孔徑分布。結(jié)果表明,兩種方法制備的多孔塊體,其氮吸附-脫附等溫曲線都屬于IV型等溫線,H3型滯后環(huán),孔徑分布為雙峰分布,樣品中都既存在介孔,也存在大孔,且都以大孔居多。利用微波-透析法制備了碳點(C-Dots),將其與CEC復(fù)合,制備了C-Dots/CEC復(fù)合膜,研究了溶液pH對C-Dots水溶液熒光性能的影響、C-Dots分散方式及含量對CEC復(fù)合膜熒光與介電性能的影響。結(jié)果表明,微波-透析法制備的C-Dots,其水溶液具有很好的pH穩(wěn)定性,經(jīng)PEG改性的C-Dots可以更均勻的分散在CEC基體中,同時熒光納米粒子的加入可以提高介電常數(shù)。
[Abstract]:With the development of electronic integration technology, the development of capacitors with smaller size, better performance and easier processing has become a new trend, which requires that the dielectric materials have higher dielectric constant. Traditional ceramic based dielectric materials have high dielectric constant, high dielectric loss, high processing temperature, poor toughness and high density. Polymer materials have the advantages of light weight, low cost, easy processing and good mechanical properties, but the dielectric constant is low. Polymer / nano-filler composites prepared by nano-composite technology have high dielectric constant while keeping polymer lightweight, easy to process and flexible, which is an important way to obtain high dielectric materials with excellent properties. In this paper, a series of composites were prepared by using cyanoethylcellulose (CEC) with high dielectric constant as matrix and graphene with good electrical conductivity as filler. The properties of CEC matrix composites with high dielectric constant were characterized. Finally, CEC matrix composites with high dielectric constant were obtained. CEC, with high degree of substitution was synthesized by using cellulose as raw material and acrylonitrile as etherifying agent. Through the study of alkali concentration, reaction time and reaction temperature, the synthesis method was optimized and the degree of substitution of CEC was controlled. Graphene oxide was prepared by modified Hummers method. Graphene / CEC high dielectric constant materials were prepared by in situ reduction of phenylhydrazine in CEC matrix solution. The results showed that the dielectric constant of the composites increased with the increase of graphene content. When the content of graphene is 0. 5 wt.%, the dielectric constant reaches 84. 4 at 100 Hz. It was also found that phenylhydrazine could not completely reduce graphene oxide. The porous bulk materials of CEC were prepared by non-solvent method and sol-gel accompanied phase separation method. The pore size and pore size distribution were studied. The results show that the nitrogen adsorption-desorption isotherm isotherms belong to the IV isotherm H3 hysteresis ring, and the pore size distribution is bimodal distribution. Both mesoporous and macropores exist in the samples, and most of them are macropores. Carbon spot (C-Dots) was prepared by microwave-dialysis method, and then C-Dots/CEC composite membrane was prepared by CEC. The effect of pH solution on the fluorescence properties of C-Dots solution was studied. The effect of dispersion mode and content of C-Dots on the fluorescence and dielectric properties of CEC composite membrane was studied. The results show that the aqueous solution of C-Dots prepared by microwave-dialysis method has good pH stability, and the C-Dots modified by PEG can be more evenly dispersed in CEC matrix, and the dielectric constant can be improved by the addition of fluorescent nanoparticles.
【學(xué)位授予單位】：北京理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB33
本文編號：2225711
[Abstract]:With the development of electronic integration technology, the development of capacitors with smaller size, better performance and easier processing has become a new trend, which requires that the dielectric materials have higher dielectric constant. Traditional ceramic based dielectric materials have high dielectric constant, high dielectric loss, high processing temperature, poor toughness and high density. Polymer materials have the advantages of light weight, low cost, easy processing and good mechanical properties, but the dielectric constant is low. Polymer / nano-filler composites prepared by nano-composite technology have high dielectric constant while keeping polymer lightweight, easy to process and flexible, which is an important way to obtain high dielectric materials with excellent properties. In this paper, a series of composites were prepared by using cyanoethylcellulose (CEC) with high dielectric constant as matrix and graphene with good electrical conductivity as filler. The properties of CEC matrix composites with high dielectric constant were characterized. Finally, CEC matrix composites with high dielectric constant were obtained. CEC, with high degree of substitution was synthesized by using cellulose as raw material and acrylonitrile as etherifying agent. Through the study of alkali concentration, reaction time and reaction temperature, the synthesis method was optimized and the degree of substitution of CEC was controlled. Graphene oxide was prepared by modified Hummers method. Graphene / CEC high dielectric constant materials were prepared by in situ reduction of phenylhydrazine in CEC matrix solution. The results showed that the dielectric constant of the composites increased with the increase of graphene content. When the content of graphene is 0. 5 wt.%, the dielectric constant reaches 84. 4 at 100 Hz. It was also found that phenylhydrazine could not completely reduce graphene oxide. The porous bulk materials of CEC were prepared by non-solvent method and sol-gel accompanied phase separation method. The pore size and pore size distribution were studied. The results show that the nitrogen adsorption-desorption isotherm isotherms belong to the IV isotherm H3 hysteresis ring, and the pore size distribution is bimodal distribution. Both mesoporous and macropores exist in the samples, and most of them are macropores. Carbon spot (C-Dots) was prepared by microwave-dialysis method, and then C-Dots/CEC composite membrane was prepared by CEC. The effect of pH solution on the fluorescence properties of C-Dots solution was studied. The effect of dispersion mode and content of C-Dots on the fluorescence and dielectric properties of CEC composite membrane was studied. The results show that the aqueous solution of C-Dots prepared by microwave-dialysis method has good pH stability, and the C-Dots modified by PEG can be more evenly dispersed in CEC matrix, and the dielectric constant can be improved by the addition of fluorescent nanoparticles.
【學(xué)位授予單位】：北京理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB33
【參考文獻】
相關(guān)期刊論文 前1條
1 李翠珍,胡開堂,余志偉;海綿狀纖維素制品的研究進展[J];林產(chǎn)化學(xué)與工業(yè);2003年03期
，本文編號：2225711
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