【作者】 张乐乐；

【导师】 张瑞丰；

【作者基本信息】 宁波大学 ， 无机化学， 2009， 硕士

【摘要】 本文利用环氧树脂和二亚乙基三胺在聚乙二醇介质中反应,制备了聚合物整体型模板,用此模板制备了大尺寸的三维二氧化硅大孔材料,并利用高频超声波研究了环氧树脂在聚乙二醇介质中的固化反应,分析相分离过程中微相结构的变化过程,具体内容如下:1.利用高频超声波对多相体系的界面Rayleigh散射作用,首次实现反应诱导相分离过程的在线跟踪。新技术用来跟踪环氧树脂在聚乙二醇介质中的固化反应,研究体系在不同浓度、不同反应介质、不同固化剂用量以及不同反应温度下的相分离过程。在对旋节线相分离模式深入分析的基础上,提出了双函数模型来描述相分离过程。将超声波散射强度与相分离速率函数以及相离散速率函数相结合,所得到的数学模型合理解释了超声波跟踪数据。2.双酚A型环氧树脂和二亚乙基三胺在PEG1000/PEG2000介质中固化反应,制得带有低交联密度和高亲水性的三维骨架聚合物(三维整体型聚合物模板)。PEG1000/PEG2000的比率控制着这个体系的反应诱导相分离。观察最终聚合物的形貌得出环氧相的连通性主要取决于PEG2000的含量而且也受固化温度的影响。通过使用PEG1000/PEG2000重量比为7/1混合物作为反应介质和致孔剂制得了带有良好可控性大孔连通通道的三维骨架聚合物。在三维骨架聚合物中充满了高折射率的液体时,发现一种独特的光过滤现象,这种效果很可能是由在三维大孔连通通道中光的全反射机理产生的。3.利用上述聚合物模板制备了三维二氧化硅大孔材料。将正硅酸四乙酯浸润此骨架聚合物表面,然后在40℃将此模板在NH3?H2O气氛中熏12小时,即形成三维二氧化硅超薄膜。通过改变正硅酸四乙酯的水解程度,膜的厚度在20-80nm可控。在820℃焙烧SiO2/聚合物形成的复合物可除去聚合物模板。三维SiO2超薄膜浸入某些高折射率的液体可形成光的全反射,通过测试此种液体折射率得到大孔二氧化硅的折射率为1.445。更多还原

【Abstract】 Three dimensional monolithic polymer template has been prepared via Bisphenol A epoxy cured with diethylenetriamine in the PEG1000/PEG2000 mixing medium, using template method we have prepared three dimensional SiO2 macroporous materials in large sizes, and high frequent ultrasonic wave was employed to track the curing reaction of epoxy resin in PEG medium,the experimental results and conclusions are summarized as follows:1. On-line tracking of reaction-induced phase separation has been realized for the first time by using high frequent ultrasonic wave, which is based on the Rayleigh scattering of ultrasonic wave on the interface of a multiphasic system. The new technology was employed to track the curing reaction of epoxy resin in PEG medium. The investigation involved the effects of concentration, reaction medium, amount of curing agent and temperature on the reaction-induced phase separation. Based on an intensive analysis of spinodal demixing in this curing system, a physical model has been put forward, in which two processes have been abstracted to describe the reaction-induced phase separation. One is the process of phase separation, and the other is phase isolation. In the related mathematical model the scattering intensity of ultrasonic wave is expressed as a function of the rates of both phase separation and phase isolation, by which the experimental data from ultasonic tracking have been explained reasonably.2. In order to prepare three dimensional skeletal polymer(3D monolithic polymer template) with low cross-linking density and high hydrophilicity Bisphenol A epoxy was cured with diethylenetriamine in the PEG1000/PEG2000 mixing medium. The reaction-induced phase separation of this system was controlled by changing the weight ratio of PEG1000 and PEG2000. The morphology observation of the resulted polymers showed that the connectivity of epoxy phase strongly depended on the content of PEG2000 and was also influenced by the curing temperature. The role of PEG2000 in the reaction system was found to be similar to that of the dispersing agent in dispersion polymerzation. A 3D skeletal polymer with well-controlled macro-through-pores was prepared by using a mixture of PEG1000 and PEG2000 in 8/1 weight ratio. A unique light-filtrating effect was first time found in the prepared 3D skeletal polymer with divinylbenzene filled in the uniform macro-through-pores. The effect most likely resulted from a total reflection mechanism of light in 3D macro-through-pores.3. Three Dimensional SiO2 macroporous materials have been prepared in large sizes via templating method. The 3D skeletal polymer used as a proper template was prepared by curing epoxy resin in polyethylene glycol mediums using diethylenetriamine as a curing agent. The formation of ultrathin silica film was accomplished on the polymer surface through the insitu hydrolysis of infiltrated ethyl silicate by exposing samples in NH3?H2O atmosphere at 40°C for 12 h. The thickness of silica ultrathin film was controlled in a range of 20～80nm by changing the amount of ethyl silicate participated in the hydrolysis. The polymer templates were removed by calcinations of silica/polymer composites at 820°C. The refractive index of ultrathin silica film was measured to be 1.445 by matching the refractive indexes of filled liquids and the fixed solid films to reach a maximum of light transmittance.更多还原