【作者】 张明艳；

【导师】 雷清泉；

【作者基本信息】 哈尔滨理工大学 ， 高电压与绝缘技术， 2006， 博士

【摘要】 聚酰亚胺作为一种高性能工程塑料,在宽广的温度范围内表现出优异的物理、化学和电性能,又因其合成工艺上具有多种途径的特点,使其制品种类繁多,广泛应用于航空/航天、电气/电子等领域。近年来,随着高新技术的发展与应用,各领域对高性能化、功能化聚酰亚胺材料的需求日益迫切。作为聚酰亚胺主要制品之一的聚酰亚胺薄膜,其应用领域不断扩大,为满足对其高性能化、功能化的需求,国内外学者针对聚酰亚胺薄膜的改性研究做了大量工作。近十年来,研究热点在于:采用溶胶-凝胶途径,将各种无机组分引入聚酰亚胺基质中,制备聚酰亚胺/无机纳米杂化薄膜,主要研究了无机纳米组分的掺杂对杂化薄膜的拉伸强度、断裂伸长率、热分解温度、玻璃化转变温度以及介电系数的影响规律,但理论分析不够深入,而对主要作为绝缘材料使用的聚酰亚胺薄膜的电性能研究鲜有报导。本文采用两相原位同步聚合技术制备聚酰亚胺/二氧化硅(PI/SiO2)纳米杂化薄膜。在掺杂胶液的制备中,有机相是通过均苯四甲酸二酐(PMDA)和4, 4′-二氨基二苯醚(ODA)在N, N-二甲基乙酰胺(DMAc)的溶液中经逐步缩聚反应制备,无机相是通过正硅酸乙酯(TEOS)或甲基三乙氧基硅烷(MTEOS)在DMAc的溶液中经溶胶-凝胶反应与聚酰胺酸原位同步生成。实验中用3-氨丙基三乙氧基硅烷(APrTEOS)做偶联剂以促进有机/无机两相的相容性。杂化薄膜的制备是将掺杂胶液浇铸在玻璃板上,经热亚胺化成膜。采用傅立叶变换红外光谱和扫描电镜能谱分析技术对杂化薄膜的化学结构进行分析,证实了杂化薄膜中有二氧化硅组分存在。用原子力显微镜和扫描电子显微镜对杂化薄膜的表面形貌和断面形貌进行表征。研究结果表明,二氧化硅的掺杂量从5wt%到30wt%变化时,采用两相原位同步聚合技术均能获得相分散程度较好的纳米杂化薄膜。以TEOS为无机前驱体时(A体系),二氧化硅纳米粒子呈球状,以MTEOS为无机前驱体时(B体系),二氧化硅粒子呈棒状。随着二氧化硅含量增加,杂化薄膜中二氧化硅与聚酰亚胺基质形成了相互贯穿的半互穿网络。研究表明:制备工艺、无机前驱体水解所需水量、偶联剂及亚胺化过程等因素对杂化薄膜的聚集态结构均有影响。采用WDW型电子万能试验机对杂化薄膜的力学性能进行了分析测试。结果表明,当二氧化硅含量为5wt%时,与纯聚酰亚胺薄膜相比,两个更多还原

【Abstract】 Polyimide (PI), as one of the highest performance engineering plastics, exhibits excellent physical, chemical and electrical properties at a large temperature range. It was used widely in aerospace, electric and electronic industries in forms of films, fibers and separation membranes and so on, because of the multi-preparation approaches and the excellent properties, including high thermal resistance, good chemical resistance and preeminent mechanical properties as well as electrical properties at elevated temperature. Along with the development and application of the new technologies, some applications, like miniaturizing of the electrical devices and manufacturing of the frequency conversion motors, however, prefer a more rigid claim to polyimide, demand high performance and functionalized polyimide. A great many researches have been carried out, domestically and abroad, on the modification of polyimide film for preparing new kind of materials to meet the increasing demand of polyimide film caused by the increasing broadened application. Great attentions were focused, mainly, on the preparation of the polyimide/inorganic nano-hybrid films through sol-gel route and the simple analysis of influences of the nano-inorganic components on tensile strength, elongation at break and thermal decomposition temperature, as well as glass transition temperature and dielectric coefficient of PI/SiO2 hybrid films. But there were seldom deep researches on the electric properties of polyimide/inorganic nano-hybrid films which served mostly as insulating materials.In this work, polyamic acid solution was synthesized by the step-polycondensation of pyromellitic dianhydride (PMDA) and 4, 4′-oxydianilline (ODA) in the solution of N, N-dimethylacetamide (DMAc). PI/SiO2 hybrid films were prepared by the hydrolysis and condensation of tetraethoxysilane (TEOS) or methyl-triethoxysilane (MTEOS) that served as the inorganic precursor and produced the nano-particles of silica in-situ in the polyamic acid solution of更多还原