粒子稳定的乳液和高内相乳液的研究.pdf

中国科学技术大学 硕士学位论文 粒子稳定的乳液和高内相乳液的研究 姓名：李停停 申请学位级别：硕士 专业：高分子化学与物理 指导教师：刘华蓉 2011-05 摘 要 I 摘 要 摘 要 随着纳米技术的发展，纳米粒子在油-水界面的吸附行为及其稳定的乳液越 来越受到人们的关注， 但目前人们对于此类乳液的研究还不是很完善 本论文中， 我们首先合成了一种新型的两亲性聚合物粒子，将其用于稳定乳液的研究；然后 合成了一种 AOA 改性的磁性纳米粒子，并将其用于高内相乳液的研究中具体 的工作内容概括如下： 1. 通过反相微乳液法合成了聚（甲基丙烯酸十八酯-co-丙烯酰胺-co-丙烯 酸） ， 这种粒子内部亲水、 外部疏水， 通过调节油溶性单体和水溶性单体的比例， 可以很方便地改善粒子的润湿性 将上述聚合物粒子用于稳定苯乙烯的正相乳液 体系，聚合之后我们得到了尺寸分布较均匀的亚微米级聚苯乙烯微球通过研究 我们发现，在乳液的制备过程中，刚开始乳化时会形成 Pickering 乳液；但是随 着时间的延长，大的液滴逐渐消失，聚合物粒子有可能被溶胀、脱落，成为种子 球，即发生 Pickering 乳液向种子乳液的转变；这是与无机粒子稳定乳液的不同 之处。

2. 通过共沉淀法制备磁性纳米粒子， 并用12-丙烯酰氧基-9-十八烯酸 （AOA） 对其进行表面改性，将改性的磁性粒子用于 St-DVB 高内相乳液（HIPE）的制备 和聚合中由于 AOA 结构中含有活性双键，经 AOA 修饰后的磁性粒子（MPs） 可以参与聚合，进一步提高了乳液稳定性和界面结合力；而且，磁性粒子的添加 对聚合物多孔材料起到一定的增强作用我们研究了 MPs 浓度和内水相含量对 高内相乳液稳定性和多孔材料结构的影响结果表明，当粒子浓度达到 20%时， 材料的杨氏模量达到最大值（69.7 MPa） ，压缩强度也提高到 5.29 MPa同时， 材料的孔洞尺寸也随粒子浓度的增大而逐渐降低并且尺寸大小趋向均匀然而， 增加内水相含量会导致材料的机械性能下降，密度降低，孔洞尺寸增加，但是有 利于多孔贯通结构的形成 3. 我们还研究了室温下 γ-射线辐射引发和 60°C 下热引发高内相乳液聚合 时，表面活性剂 Span 80 的浓度对乳液稳定性和多孔材料结构形貌的影响结果 发现，室温下引发聚合有利于乳液的稳定，而且当表面活性剂的用量降低到 1.4 wt%时，依然可以获得良好的多孔贯通的聚合物大孔材料。

关键词：关键词：Pickering乳液 种子乳液 辐射聚合 高内相乳液 大孔材料 ABSTRACT II ABSTRACT With the development of nanotechnology, the adsorption behavior of nano-particles in the oil - water interface and the stability of the emulsion attract more and more attention, but the study of such emulsions is not very systemic. In this thesis, we first synthesized a new kind of amphipathic polymer particles, and used them to stablilize emulsion; then synthesized magnetite nanoparticles surface-modified with AOA for the study of high internal phase emulsion (HIPE). The specific contents of the work are summarized as follows: 1. Poly(stearyl methacrylate-co-acrylamide-co-acrylic acid) [P(SMA-co-AM-co- AA)] was synthesized through inverse microemulsion polymerization which owns the hydrophilic interior core and hydrophobic surface. By changing the ratio of oil-soluble monomers to water-soluble monomers, it is easy to control the wettability of nanoparticles. The P(SMA-co-AM-co-AA) nanoparticles were used to stabilize styrene- water emulsion, and submicron-sized polystyrene (PS) microspheres with a relatively narrow particle size distribution were obtained after polymerization. We found that Pickering emulsion was first formed after emulsification, but the big droplets disappeared grasually with the passage of time, and the polymer nanoparticles might be swollen, dropped off and became seeds, namely Pickering emulsion would change into seeded emulsion afterwards，which is different from the emulsions stabilized by inorganic particles. 2. Magnetite nanoparticles (MPs) modified with 12-acryloxy-9-octadecenoic acid (AOA) were synthesized by the coprecipitation method, and St-DVB HIPEs were prepared solely stabilized by MPs. Due to the existence of an active double bond in the structure of AOA, AOA-modified magnetite nanoparticles would take part in the polymerization, improving on their binding to the interface and the stability of HIPE. Moreover, MPs play an important role in the reinforcement for macroporous polymer foams. We studied the effects of MPs concentration and internal phase weight fraction on the stability of HIPE and the structure of macroporous materials. It is found that when the concentration of MPs was 20 wt% based on oil phase, the Young’s modulus reached to the maximum value (69.7 MPa) and the compression strength was improved to 5.29 MPa. Meanwhile, the void sizes and size distributions decreased with increasing the content of MPs until up to 20 wt%. However, increasing the ABSTRACT III internal phase fraction would lead to the decrease of mechanical properties and foam density and the increase of voids size, but it is favorable for the formation of macroporous interconnected structure. 3. We also studied the effect of the surfactant Span 80 concentration on the stability of HIPE and the structure of macroporous materials when the polymerization is initiated by γ-ray at room temperature or by chemical initiator at 60°C. The results showed that it is beneficial to the stability of HIPE when polymerized at room temperature, and even if the Span 80 concentration is as low as 1.4 wt% we can still obtain macroporous interconnected polymer materials. Keywords: Pickering emulsion, seeded emulsion, radiation polymerization, high internal phase emulsion, macroporous materials 中国科学技术大学学位论文原创性声明 本人声明所呈交的学位论文,是本人在导师指导下进行研究工作所取得的成 果。

除已特别加以标注和致谢的地方外，论文中不包含任何他人已经发表或撰写 过的研究成果 与我一同工作的同志对本研究所做的贡献均已在论文中作了明确 的说明 作者签名：___________ 签字日期：_______________ 中国科学技术大学学位论文授权使用声明 作为申请学位的条件之一， 学位论文著作权拥有者授权中国科学技术大学拥 有学位论文的部分使用权，即：学校有权按有关规定向国家有关部门或机构送交 论文的复印件和电子版，允许论文被查阅和借阅，可以将学位论文编入《中国学 位论文全文数据库》等有关数据库进行检索，可以采用影印、缩印或扫描等复制 手段保存、 汇编学位论文 本人提交的电子文档的内容和纸质论文的内容相一致 保密的学位论文在解密后也遵守此规定 □公开 □保密（____年） 作者签名：_______________ 导师签名：_______________ 签字日期：_______________ 签字日期：_______________ 第一章 绪论 1 第一章 绪 论 第一章 绪 论 1.1 引言 近年来，以固体粒子稳定的乳液越来越受到人们的关注，它们的应用范围比 较广泛，在化妆品、医药学、食品工业等方面有着重要的应用价值。

Pickering 等 人 1 对这种乳液体系做了系统的研究工作，因此这类乳液又被称为 Picker。