【作者】 咸华风；

【导师】 罗艳；

【作者基本信息】 东华大学 ， 应用化学， 2012， 硕士

【摘要】 基于电泳显示的电子纸已成为当今应用领域的研究热点,其中微胶囊电子墨水是电子纸显示的核心技术。而当前微胶囊电泳显示存在明显的缺点,例如只能做黑白双色显示,更新频率过慢,仅采用彩色滤光板技术,多使用无机颜料作为电泳颗粒等。通过微加工技术和精密加工技术制造的Y型微通道反应器主要用于有机合成的研究。由于反应过程中,两股反应液在混合同时也可进行乳化,故可制备具有高度分散液滴的乳液,从而获得尺寸均一,大小可控的微胶囊。但国内尚无此类相关微胶囊制备研究的文献报道。鉴此,本文对由酞菁蓝和TiO2组成的电泳粒子表面进行修饰,以加强其在四氯乙烯介质中的分散性,使其满足电泳显示的要求。采用红外光谱仪、扫描电子显微镜和热失重分析仪等分析测试手段,对电泳粒子的改性效果进行表征。以分散有电泳粒子的四氯乙烯为芯材,蜜胺树脂为壁材通过原位聚合法制备电泳显示微胶囊。并采用光学显微镜、扫描电子电镜、表面张力仪、激光粒径分布仪等分析测试手段,对所制备的微胶囊粒径分布、表面形态、包封率进行表征,探索乳化剂种类、乳化剂浓度、芯壁比和pH值等工艺条件对所制备电泳微胶囊性能的影响。搭建Y型微通道反应装置,通过改变两流动相配比和流速比,采用光学显微镜作为测试手段,研究不同流动相配比和流速比对微胶囊制备的影响。得出以下结论：酞菁蓝在四氯乙烯中的分散程度较差,用十八胺对酞菁蓝进行表而改性,十八胺与酞菁蓝之间由于形成氢键而吸附在一起,增强了酞菁蓝在油性介质中的分散稳定性。分散程度测试表明十八胺改性后的酞菁蓝在四氯乙烯中的分散程度达到90%,符合电泳粒子的要求。金红石型TiO2密度较大,约为4.0g/cm3且具有亲水表面,使用硅烷偶联剂K570对其进行改性,K570水解生成的Si-OH与TiO2表面的-OH形成氢键接枝于TiO2的表面,成功的使TiO2表面由亲水变为亲油；亲油表面改性后的TiO2用聚苯乙烯进行包覆,苯乙烯单体和TiO2表面的C=C双键共聚从而包覆于TiO2表面,最终形成一种核-壳微球结构。通过热失重分析计算出聚苯乙烯TiO2微球密度为1.78g/cm3,与密度为1.62g/cm3的四氯乙烯较为相近,符合电泳粒子的要求。通过对不同类型表面活性剂的筛选,发现高分子型表而活性剂苯乙烯马来酸酐共聚物(PDA)是制备蜜胺树脂电泳显示微胶囊的理想乳化剂,其最佳工艺条件为：乳化剂浓度为1.0wt%、芯壁比为2.5、pH值为5.0。实验室搭建的Y型微通道反应器暂时无法成功制备微胶囊,主要与蜜胺树脂壁材的成囊反应有关,但经其流出的乳液大小十分均匀且形态良好,若进一步探索成囊反应机理,有望制得具有极佳的均一性和表面形态的电泳显示微胶囊。更多还原

【Abstract】 The electronic paper which is based on electrophoretic display has already been a research hotspot. The key technology of the electronic paper is in the preparation of microcapsule electronic ink. Microcapsule electronic display, however, exhibits some defections such as monochrome display, slow renew frequency, only applying color filter tabula rasa and mainly using inorganic particles as electrophoretic particles etc.Y-shape micro channel reactor manufactured by the technology both of surface micromachining and of precision machining, is mainly used for the study of organic synthesis. When using Y-shape micro channel reactor, two reaction-liquid can be emulsified evenly and highly dispersed emulsion can be obtained. As the result, the uniform and size-controlled microcapsules can be prepared. So far, the applications of preparing microcapsules by Y-shape micro channel reactor were rarely reported in China.In this paper, electrophoretic particles containing phthalocyanine blue and TiO2 were surface modified to improve their dispersibility in tetrachloroethylene (TCE). Infrared Spectrum, Scanning Electron Microscope (SEM) and thermogravimetry analysis (TG) were used to characterize the result of modificated samples. The microcapsules used for electrophoretic display were prepared by in-situ polymerization. The core material contained electrophoretic particles (phthalocyanine blue and TiO2) and TCE, and the wall material were made of melamine-formaldehyde resin. The Optical Microscope, SEM, Surface Tensiometer and Static Light Scattering were used to characterize the particle size distributions, surface morphology and coating rate of microcapsules. The type and concentration of surfactant, the ratio of core material to wall material and the pH values were all experimentally investigated. Meanwhile, Y-shape micro channel reactor was built. The effect of different flowing phase and speed ratio on microcapsules preparation was studied respectively using Optical Microscope.The main results are summarized as follow:Octadecylamine can used to modify phthalocyanine blue, which had poor dispersibility in TCE. Hydrogen bond can be observed between Octadecylamine and phthalocyanine blue by FTIR, so that the dispersibility of phthalocyanine blue in TCE was enhanced greatly. The results of dispersing extent test suggested that the dispersing extent of phthalocyanine blue in TCE was up to 90%. Hence the modified phthalocyanine blue is suitable for being electrophoretic particles. 3-(trimethoxysilyl) propyl methacrylate (K570) was used to modify the TiO2, whose density is 4.0g/cm3 and surface is hydrophilic. Si-OH can be generated by the hydrolysis of K570. Then the Si-OH and the-OH which was on the surface of TiO2 formed the hydrogen bond. As a result, K570 was fixed to the surface of TiO2. Thus the surface of TiO2 was turned from hydrophilic to lipophilic. If the lipophilic TiO2 was coated with polystyrene (PS), styrene and C=C double bond of TiO2 can copolymerized. Therefore, TiO2/PS Core-Shell particles were obtained. Due to the similar density,1.78g/cm3 of TiO2/PS Core-Shell particles and 1.62g/cm3 of TCE, the modified TiO2 is suitable for using in electrophoretic display.After selecting different types of surfactants, macromolecule surfactant of Styrene-maleic anhydride copolymer (PDA) was found to be the appropriate surfactant for the preparation of melamine-formaldehyde resin microcapsules. The optimum preparation condition was as follow: concentration of surfactant is 1.0wt%, mass ratio of core material to wall material is 2.5, and pH value is 5.0.Microcapsules could not be formed with the built Y-shape micro channel reactor. It might be related to the capsulation reaction. However, the emulsion was of regular morphology. If the mechanism of capsulation reaction can be studied further, the microcapsules with regular morphology are expected to be prepared.更多还原