【作者】 马艳；

【导师】 陈宇飞；

【作者基本信息】 哈尔滨理工大学 ， 高分子化学与物理， 2008， 硕士

【摘要】 聚酰亚胺因具有高热稳定性、高强度与高模量、低热膨胀系数和介电常数、优异的绝缘性能和耐溶剂性等优异性能而被广泛地应用于航空航天、军事、电气电子等工业领域。但是由于它是有机高聚物,耐电晕性差,限制了其在高压电动机及变频调速电机系统中的应用,鉴于在有机-无机纳米复合材料在聚合物材料改性方面的应用,对PI纳米复合材料的发展也提出了新的要求。本文采用3,3′,4,4′-二苯甲酮四甲酸二酐(BTDA)、3,3′-二乙基-4,4′-二胺基二苯甲烷(DEDADPM)和纳迪克酸酐(NA)为原料,利用两步合成法合成聚酰胺酸(PAA),再通过化学亚胺化方法制备热固性聚酰亚胺。同时采用溶胶-凝胶法合成无机纳米氧化铝并反方式加料,再加入偶联剂乙烯基三(β-甲氧基乙氧基)硅烷,然后在一定温度梯度下固化成纳米复合材料。采用傅立叶变换红外光谱(FT-IR)、原子力显微镜(AFM)、扫描电子显微镜(SEM)、X射线衍射仪(XRD)和热重分析仪(TGA)分别表征复合材料的化学结构、聚集态结构和热性能,并利用耐电晕测试装置和介电谱仪对其电性能进行了表征。结果表明:当铝氧化物掺杂量达16wt%时,Al2O3粒子均匀地分布于有机相PI树脂基体中,两相间的界面变得模糊。偶联剂的加入使无机纳米粒子尺寸明显减小,分散更均匀,团聚现象减弱,粒径分布变窄。当Al2O3含量为16wt%时,比掺杂前PI提高了16.75℃;酮酐型聚酰亚胺的热分解温度为482.88℃,均酐型聚酰亚胺的热分解温度为472.56℃,酮酐型固化物的热分解温度明显高于均酐型固化物的热分解温度。掺杂前PI的耐电晕时间为11h,当铝氧化物掺杂量增加时,复合材料的耐电晕性能显著增强,当掺杂16wt%时,耐电晕时间达到165小时,比掺杂前PI提高了14倍。聚酰亚胺复合材料在所有测试频率下介电常数和介电损耗随着铝氧化物掺杂量的增加呈现上升趋势。酮酐型固化物比均酐型固化物的介电常数和介电损耗略高。更多还原

【Abstract】 Polyimide (PI) that serves as a typical kind of engineering polymer material has been used widely in the aerial, martial and electric industries, because of its outstanding characteristics, such as excellent thermal stability, relatively high tensile strength and modulus, low thermal expand coefficient, preminent insulation capability and solvent resistance. However, as high polymer it has inferior corona-resistance property, which limits its application in the fields of high voltage electromotor and variable frequency adjusting speed. The application of organic-inorganic nano composites in the aspect of modification demands high developmet of PI nano composite material too.The thermosetting polyimide material was prepared from 3,3’-diethyl-4,4’-diamino diphenyl methane (DEDADPM), 3,3’,4,4’-benzophenone tetracarboxylic dianhydride (BTDA) and nadic anhydride (NA), and chemical imide process was used. Alumina was added by reverse sequence, via Sol-gel method, then A-172 was added, and nano-composite material was solidied at some temperature grades at last.The chemical structure, aggregation structure and the thermal properties of the composite material were respectively characterized by Fourier Transform Infrared Spectroscope (FT-IR), Atomic Force Microscope (AFM), Scanning Electronic Microscope (SEM), X-ray Diffraction(XRD), Thermogravimetric Analysis (TGA), and their electric properties were characterized by corona discharge measuring equipment and dielectric spectrometer. All the results indicated that Al2O3 particals spreaded uniform in the PI resin matrix, and the two phase interface became very faint, when the amount of alumna was 16wt%. The adding of A-172 make the inorganic nano particles dimensions minish, spread uniform, reunite decrease, distribution of particles diameter narrow. When the amount of alumna was 16wt%, the thermal decomposition is 16.75℃higher than that of pure PI. The thermal decomposition temperature of BTDA-PI was 482.88℃, the thermal decomposition temperature of PMDA-PI was 472.56℃, the thermal decomposition temperature of BTDA-PI was higher than that of the PMDA-PI very much. The corona-resistant lifespan of pure PI material is 11 hours, as the amount of alumina increased, the corona-resistant property of the composite material increased greatly, and that of the PI film with 16wt% amount of alumina was 165 hours, 14 times longer than that of pure material. At all test frequencies, the dielectric constant and the dielectric loss of the PI composite growed with the amout of alumina increased. The dielectric constant and dielectric loss of BTDA-PI were higher than that of the PMDA-PI.更多还原