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1、西安科技大学 硕士学位论文 基于Pickering乳液制备功能材料研究 姓名：张超 申请学位级别：硕士 专业：应用化学 指导教师：贺拥军 2011 论文题目：基于 Pickering 乳液制备功能材料研究 专 业：应用化学 硕 士 生：张 超 (签名) 指导教师：贺拥军 (签名) 摘 要 Pickering乳液是基于固体粒子稳定作用形成的乳状液，在新材料合成、催化反应等 具有重要应用前景。本论文基于Pickering乳液介质合成出MgO/Mg(OH)2空心球壳、MgO 空心球壳、含水聚苯乙烯复合阻燃材料，进行了结构表征，并测试了其应用性能。 以Pickering乳液的液滴为模板，通过液滴表面M
2、gO水合作用，制备了MgO/Mg(OH)2 复合空心球壳。用SEM、XRD、BET等手段对空心球壳进行了表征，探讨了其形成机理。 制备的MgO/Mg(OH)2复合空心球壳粒径分布均匀，平均粒径为62m。Pickering乳液油 水界面的部分MgO通过水化反应转变成Mg(OH)2，复合在未反应的MgO粒子上，形成 MgO/Mg(OH)2复合空心球壳。 将复合空心球壳应用于阿维菌素的缓释。 紫外分光光度法 测定结果表明，阿维菌素微胶囊释放可分为前期快速释放阶段和中后期稳定释放阶段， 以MgO/Mg(OH)2复合空心球壳做壁材的阿维菌素微胶囊具有良好的缓释效果。 MgO/Mg(OH)2空心球壳经焙烧
3、后得到 MgO 空心球壳。结果表明，MgO 空心球壳 为方镁石结构，比表面积为 28m2/g，表面由平均宽度为 65nm 的纳米片层构成。将纳米 结构 MgO 空心球壳应用于水中镍离子的脱除，探讨了处理剂用量、温度、搅拌时间、 沉降时间等操作参数对脱除效果的影响作用，并对镍离子的脱除机理进行了分析。结果 表明，纳米结构 MgO 空心球壳对 Ni2+的沉降性能与 MgO 纳米粒子相近，并且易于通过 简单的过滤过程分离出来。当纳米结构 MgO 空心球壳用量为 0.4g/L 时，溶液(初始浓度 25mg/L)中 Ni2+的去除率为 98.3%。 以Pickering乳液液滴为模板，通过偶氮二异丁腈引
4、发苯乙烯聚合，制备出含水 Mg(OH)2/聚苯乙烯复合阻燃材料。 结果表明， Mg(OH)2/聚苯乙烯复合阻燃材料中存在平 均直径为155m的孔洞，能够包裹一定质量的水。随着聚合温度的提高，复合阻燃材料 的含水量下降。含水复合阻燃材料由于具有水和Mg(OH)2的双重阻燃作用，氧指数显著 高于Mg(OH)2/PS复合材料，但其力学性能有所下降。 关 键 词： Pickering乳液；空心球壳；纳米结构； MgO纳米粒子；阻燃；微胶囊 研究类型： 基础研究 Subject ：Research on Preparation of Functional Materials in a Pickering
5、 Emulsion Specialty ：Applied Chemistry Name ：Zhang Chao (Signature) Instructor ：He Yongjun (Signature) ABSTRACT When some fine solid powders were mixed with water and an oily solvent, a solid-stabilized emulsion (often referred to as a Pickering emulsion) could be obtained even if no surfactants wer
6、e used. Recently, Pickering emulsions have been found to be a suitable medium in many frontiers, such as the preparation of functional materials, catalytic reaction. With the droplets of a Pickering emulsion as templates, MgO/Mg(OH)2 hollow microspheres, MgO hollow microspheres and water-containing
7、Mg(OH)2/PS composites were prepared. The structure and performance of the products were characterized. MgO/Mg(OH)2 hollow microspheres were prepared with the droplets of a Pickering emulsion as templates. MgO/Mg(OH)2 microspheres were formed via a hydration reaction of MgO at the oil/water interface
8、s. The products were characterized by SEM, XRD and BET measurement. A possible mechanism of an interfacial hydration reaction was proposed. The images of SEM showed that the MgO/Mg(OH)2 microspheres had an average diameter of 62 m. During the hydration, part of the MgO particles turned into Mg(OH)2,
9、 and clinged to the surface of MgO. MgO/Mg(OH)2 hollow microspheres formed. The controlled-release formulation of avermectins microcapsule encapsulated with MgO/Mg(OH)2 hollow microspheres was studied. The results showed that, avermectin in the microcapsules release quickly at beginning and stablely
10、 later. Avermectins microcapsules displayed good controlled-release characteristics and satisfied the necessary prerequisites for prolonged control period. After calcinations, MgO/Mg(OH)2 hollow microspheres turned into MgO hollow microspheres. The MgO microspheres were of periclase structure and ha
11、d a specific surface area of 28 m2/g. The surfaces of the MgO microspheres were made up of nanoflakes with an average thickness of 65 nm. The adsorptive ability of the MgO microspheres to Ni2+ was investigated. The effect of the treatment agents dosage, temperature, mixing time, stirring time and se
12、ttling time on the removal ratio was analyzed. The results showed that, the MgO microspheres had a similar adsorptive ability to Ni2+ to that of MgO nanoparticles, while were more easily separated from the aqueous solution by simple filtration procedure. With the dosage of 0.4g/L, the concentration
13、of Ni2+ decreased to 1.7% Water-containing Mg(OH)2/PS composites were prepared by a polymerization reaction with the droplets of a Pickering emulsion as templates. The results showed that the Mg(OH)2/PS composites had holes with an average diameter of about 155m, which served as reservoirs for water
14、. With the increase of polymerization temperature, the amount of water in the composites decreased. The mechanical properties of the water-containing Mg(OH)2/PS composites decreased, however, the oxygen index of the composites was much higher than that of the ordinary Mg(OH)2/PS composites, due to t
15、he dual flame retardant effect of water and Mg(OH)2。 Keywords: Pickering emulsion Hollow microspheres Nanostructures MgO nanoparticles Flame retardant Microcapsule Thesis : Basic theoretical research 1 绪论 1 绪论 1.1 Pickering乳液 乳状液(Emulsions)是由两种互不相溶的液相组成的混合体系，其中一相以液滴的形 式分散于另一相中。由于油水界面积比较大，且通常油水相互不相溶，
16、所以乳状液是一 种热力学极不稳定的体系。通常需要向体系中添加乳化剂，降低表面张力，才能获得稳 定的乳液。人们对于此类表面活性剂稳定乳液的研究从理论上和实际应用上相对成熟， 并且广泛应用于食品、化妆品、涂料、医药、农业以及乳液合成等领域。但是在固体粒 子对乳液稳定性影响方面认识较少。早在 1903 年，Ramsden1首先发现不溶性细粉能够 代替传统的表面活性剂稳定乳液，所形成的稳定乳液被称为固体稳定乳液(Solid stabilized emulsion)。Pickering2随后对其进行系统而全面的研究工作，正式提出固体粒 子稳定乳液的存在，因此，固体粒子稳定的乳液被称为 Pickering 乳液。近年来，Binks 等3-4在固体粒子稳定乳液研究方面作了大量的工作，分析了固体粒子稳定乳液的制备 特性，通过固体粒子在油水界面的吸附实现稳定乳状液，考察了固体粒子稳定乳液的稳 定机理、影
