【作者】 李欣；

【导师】 孙秋；

【作者基本信息】 哈尔滨工业大学 ， 化学工程与技术， 2020， 硕士

【摘要】 随着现代科技的发展进步,集成电路在现代电子器件和电力系统（如医疗设备、混合动力汽车（HEVs）、过滤器、开关电源和动力武器系统）中具有广阔的应用前景;聚脲以开路故障小、重量轻、击穿强度高、与有机基板或印刷电路板的相容性好等特点引起了人们的关注。本文通过制备两种不同结构的聚脲以及以聚脲薄膜为基体进行陶瓷纳米粒子和导体材料的掺杂改性,达到进一步提高基体聚合物的介电常数的目的。利用常温下的介电常数、不同电场下的D-E回线来分析样品的介电、储能性能。本文采用溶液聚合的方式,利用4,4’-二氨基二苯醚（ODA）与4,4’-亚甲基双（异氰酸苯酯）（MDI）通过控制不同反应条件与异氰酸酯指数（R）制备芳香族聚脲薄膜ArPUⅠ,当R为1.06时,聚合反应进行的最为充分,各方面性能最优,此时ArPUⅠ的介电常数在频率大于103 Hz时可以稳定在5.89。在此基础上,向结构中引入间苯二胺（m PDA）,控制其摩尔分数为二胺比例的0%～50%,以10%的梯度递增,制备偶极密度更高的芳香族聚脲薄膜ArPUⅡ系列薄膜;其中ArPUⅡ-20%在保持良好的力学与热稳定性的基础上,击穿场强可达516 MV/m,进而得到最高的储能密度为6.65 J/cm³。以ArPUⅡ-20%为基体,向其中掺杂质量分数为0%～1.5%的PDA@MWCNTs,制备PDA@MWCNTs/ArPUⅡ复合薄膜;利用溶胶-凝胶法制备钛酸钡纳米颗粒,通过原位共混的方式得到BT-HN₂掺杂质量分数为0%～25%的BT/ArPUⅡ复合薄膜。当PDA@MWCNTs的质量分数在1.25%时,薄膜的介电常数接近11,为基础薄膜介电常数的2倍左右,MWCNTs含量的增加薄膜的击穿场强所有下降。BT的加入会使薄膜的力学性能下降,介电常数不断升高,常温下加入10%的BT,复合薄膜的介电常数即可达到8左右,但在高频处介电损耗较为明显。BT/ArPUⅡ-5%在500 MV/m电场下的有效储能密度达到7 J/cm³。本文制备的系列薄膜力学性能良好且均具有良好的热稳定性,可高温环境（200℃）下使用,填料的加入会提高基体薄膜的热分解温度,进而扩大复合薄膜的使用范围。更多还原

【Abstract】 With the development of modern technology,the circuit has broad application prospects in modern electronic devices and power systems（such as medical equipment,hybrid electric vehicles（HEVs）,filters,switching power supplies and power weapon systems）;Polyurea has attracted people’s attention due to its small open circuit failure,light weight,high breakdown strength,good compatibility with organic substrates or printed circuit boards,and other characteristics.In this paper,we prepared two kinds of polyurea with different structures and then doping modification of ceramic nanoparticles and conductor materials with polyurea film as the matrix,the dielectric constant of the matrix polymer is further improved.Using the impedance value at normal temperature,the applied electric field strength and the D-E loops under different electric fields to analyze the dielectric and energy storage performance of the samples.In this paper,the ArPU Ⅰ polyurea films were prepared by solution polymerization method,using MDA and MDI though controlling different reaction conditions and isocyanate index（R）.When R is 1.06,the polymerization proceeds most fully and the performance is optimal in all aspects.At this time,the dielectric constant of ArPU Ⅰ can be stabilized at 5.89 when the frequency is greater than 103 Hz.Based on this,m PDA was introduced into the structure,and its molar fraction was controlled to be 0 % ～ 50 % of the diamine ratio,and the gradient was increased by 10 % to prepare ArPU Ⅱ series films with higher dipole density;Among them,ArPU Ⅱ-20 %,on the basis of maintaining good mechanical and thermal stability,the breakdown field strength can reach 516 MV/m,and the highest energy storage density is 6.65 J/cm³.PDA@MWCNTs/ArPU Ⅱ composite film was prepared with ArPU Ⅱ-20 % as the matrix and doped with PDA@MWCNTs with a mass fraction of 0 % ～ 1.5 %;The sol-gel method was used to prepare barium titanate nanoparticles,and a BT / ArPU Ⅱ composite film with a BT-HN₂ doped mass fraction of 0 % ～ 25 % was obtained by insitu blending.When the mass fraction of PDA@MWCNTs is 1.25 %,the dielectric constant of the film is close to 11,which is about 2 times the dielectric constant of the base film.As the MWCNTs increases,the breakdown field strength of the film decreases.The addition of BT will reduce the mechanical properties of the film,but the dielectric constant will continue to increase.When 10 % BT is added at room temperature,the dielectric constant of the composite film can reach about 8,but the dielectric loss is obvious at high frequencies.The effective energy storage density of BT/ArPU II-5 % under 500 MV/m electric field reaches 7 J/cm³.The series of films prepared in this paper all have good mechanical properties and good thermal stability.They can be used in high temperature environments（200 °C）.The addition of fillers will increase the thermal decomposition temperature of the base film,thereby expanding the use of the composite film.更多还原