【作者】 牛颖；

【导师】 张明艳；

【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】 近年来,聚酰亚胺/二氧化硅（PI/SiO₂）纳米杂化材料已成为合成高分子材料新的研究热点。目前为止,国内外学者对PI/SiO₂纳米杂化薄膜已经进行了大量的研究,主要集中在PI/SiO₂纳米杂化薄膜的合成以及力学性能、热性能、电性能等方面。关于不同掺杂条件对PI/SiO₂杂化薄膜聚集态结构的影响研究较少,目前尚未形成完整的关于纳米复合材料性能与聚集态结构之间关系的研究体系。本文采用两步法,两相原位同步聚合技术制备PI/SiO₂纳米杂化薄膜。以均苯四甲酸二酐（PMDA）和4, 4′-二氨基二苯醚（ODA）为有机单体,通过其在N, N-二甲基乙酰胺（DMAc）中的逐步缩聚反应制备聚酰胺酸（PAA）;以正硅酸乙酯（TEOS）为无机前驱体,通过其在DMAc的溶液中经溶胶-凝胶反应与聚酰胺酸原位同步生成无机相SiO₂,得到杂化PAA胶液,经热亚胺得到PI/SiO₂纳米杂化薄膜。本文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）、广角X射线衍射仪（WAXD）分析了PAA杂化胶液固体含量、水含量、溶剂和热亚胺化工艺对PI/SiO₂纳米杂化薄膜聚集态结构的影响。研究结果表明,本实验工艺路线能够成功制备出PI/SiO₂纳米杂化薄膜。以上四种工艺参数均对PI/SiO₂纳米杂化薄膜聚集态结构有不同程度的影响。当固体含量在一定范围内时,SiO₂粒子粒径随固体含量增加而增加。水含量过多或过少对杂化薄膜聚集态结构均产生不利影响。采用不同溶剂时,PI/SiO₂纳米杂化薄膜聚集态结构也不同。在本论文采用的8种溶剂体系中,以N-甲基-2-吡咯烷酮（NMP）/二甲苯为溶剂时,SiO₂粒子粒径最小,两相界面模糊。在热亚胺化过程中,适当增加60oC低温区域停留时间;将亚胺化终止温度达到350oC,并延长350oC的停留时间;减慢高温区升温速率是增加两相相互作用,减少SiO₂粒径尺寸的有效方法。更多还原

【Abstract】 Recently, great attentions have been focused, mainly, on the preparation of polyimide/silica （PI/SiO₂） nano-hybrid films and properties such as mechanical property, thermal stability and so on. But there were seldom systematical researches about the influences of different incorporating conditions on the aggregation structure, and the perfect study system has not been formed about the relationship between properties and aggregation structure of PI/SiO₂ nano-hybrid films.In present study, polyamic acid/silica solutions were synthesized via Sol-Gel route by the hydrolysis and condensation of tetraethoxysilane （TEOS） that served as the precursors of the inorganic moiety and produced the silica nano-particles in-situ in the polyamic acid solution （PAA） based on the stepwise polycondensation of pyromellitic dianhydride （PMDA） and 4, 4′-oxydianiline （ODA） in N, N-dimethylacetamide （DMAc）. PI/SiO₂ hybrid film was obtained by casting PAA/silica solution onto glass substrate, followed by thermally imidizing. The chemical structure and aggregation structure of PI/SiO₂ films were respectively characterized by Fourier Transform Infrared Spectroscope （FT-IR）, Atomic Force Microscope （AFM）, Scanning Electronic Microscope （SEM）, Wide-angle X-ray Diffraction （WAXD）. The influence of solid content of PAA hybrid solutions, deionized water content, solvent and thermal imidization process on the aggregation structure of PI/SiO₂ nano-hybrid films was studied. All results indicated that PI/SiO₂ nano-hybrid films have been prepared by schematic route of this experiment successfully. The aggregation structure of PI/SiO₂ nano-hybrid film was influenced by four kinds of technical parameters above. The sizes of silica particles increased with solid content increasing in a certain content range. The content of deionized water was very important to the aggregation structure of PI/SiO₂ nano-hybrid films. In the eight kinds of solvents system, the sizes of silica particles were the smallest, and the interface between organic and inorganic phases was obscure using N-methyl-2-pyrrolidone （NMP）/ dimethyl benzene as solvent. In thermal imidization process, it is all effective methods to reduce silica particle size that extending residence time at 60oC, improving final temperature to 350oC, extending residence time at 350oC and reducing heating rate in high temperature area.更多还原