CEC基高介电常数复合材料的制备与研究
发布时间：2018-09-06 07:52
【摘要】：伴随着电子集成技术的发展,开发体积更小、性能更优异及加工更容易的电容器成为新的趋势,这就要求其中的电介质材料具有更高的介电常数。传统的陶瓷基介电材料虽然介电常数高,但其介电损耗高,加工温度高,韧性差,密度大。高分子聚合物材料具有轻质、低成本、易加工、机械性能良好等优点,但介电常数较低。通过纳米复合技术制备聚合物/纳米填料复合材料,在保持聚合物轻质、易加工及柔韧性的同时,具备较高的介电常数,是获得性能优良的高介电材料的重要途径。本文以本征介电常数高的氰乙基纤维素(CEC)为基体,以具有良好导电性能的石墨烯为填料,制备了一系列复合材料,表征了其性能,最终获得了高介电常数的CEC基复合材料。以纤维素为原料,以丙烯腈为醚化剂,采用溶媒法合成出高取代度的CEC,通过对碱化浓度、反应时间、反应温度等因素的研究,优化合成方法,实现了CEC取代度的可控。利用改进的Hummers法制备氧化石墨烯,以苯肼为还原剂,在CEC基体溶液中原位还原制备了石墨烯/CEC高介电常数材料,结果表明,随着石墨烯含量的增大,复合材料的介电常数增大,当石墨烯含量为0.5 wt.%时,100 Hz下的介电常数达到了84。同时研究还发现,苯肼不能完全还原氧化石墨烯。采用非溶剂法和溶胶-凝胶伴随相分离两种方法制备了CEC的多孔块体材料,研究了其孔径及孔径分布。结果表明,两种方法制备的多孔块体,其氮吸附-脱附等温曲线都属于IV型等温线,H3型滞后环,孔径分布为双峰分布,样品中都既存在介孔,也存在大孔,且都以大孔居多。利用微波-透析法制备了碳点(C-Dots),将其与CEC复合,制备了C-Dots/CEC复合膜,研究了溶液pH对C-Dots水溶液荧光性能的影响、C-Dots分散方式及含量对CEC复合膜荧光与介电性能的影响。结果表明,微波-透析法制备的C-Dots,其水溶液具有很好的pH稳定性,经PEG改性的C-Dots可以更均匀的分散在CEC基体中,同时荧光纳米粒子的加入可以提高介电常数。
[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.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33
本文编号：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.
【学位授予单位】：北京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33
【参考文献】
相关期刊论文 前1条
1 李翠珍,胡开堂,余志伟;海绵状纤维素制品的研究进展[J];林产化学与工业;2003年03期
，本文编号：2225711
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