【作者】 汪冀；

【导师】 张福强；

【作者基本信息】 河北工业大学 ， 高分子化学与物理， 2011， 硕士

【摘要】 空心乳液是一种特殊的核壳乳液,一般是指通过乳液聚合法制备出来的内部具有空腔的乳液,干燥后形成球状空心结构。空心乳液由于具有中空结构,其外部壳层聚合物与空腔内的空气对光的折射系数不同,入射光能被有效散射,因而具有良好的遮盖效果和优异的白度。目前空心乳液多作为替代钛白粉的白色塑料颜料应用于涂料、水性油墨、低定量涂布纸等领域。除此之外也可用作微胶囊材料和抗紫外线添加剂等。自上世纪八十年代问世以来,空心乳液良好的应用前景引起了人们的广泛关注。本文采用半连续滴加法制备了具有空心结构的聚合物乳液。制备过程中,首先以甲基丙烯酸甲酯和丙烯酸丁酯为共聚单体合成了种子乳液,然后加入甲基丙烯酸、甲基丙烯酸甲酯、丙烯酸丁酯和二乙烯基苯进行共聚合,制备了带羧基的亲水性核。用苯乙烯、丙烯酸乙酯、丙烯酸丁酯和二乙烯基苯为共聚单体制备了具有疏水性壳层的核壳乳液。最后在90℃下用碱溶液对其进行溶胀处理,得到了空心乳液。本文详细研究了反应温度、乳化剂、中和度、单体组成、核壳比等因素对乳液遮盖性能、粘度及乳胶粒结构的影响。采用透射电子显微镜分析了乳胶粒的形态结构,用动态光散射和透射电子显微镜表征了乳胶粒直径和内腔直径。结果表明:核壳比、中和度、MAA、BA与St用量等因素影响空心乳液的结构及性能。随着核壳比从1/20提高到1/8,乳液的遮盖能力增强,白度提高,当核壳比为1/8,中和度为40%时乳液白度达92.4,同时当MAA在种子单体中用量为28%,BA与St质量比为1/10时,白度达94.4。为了研究空心乳液结构和遮盖性能的关系,本文结合Mie散射理论通过合理假设和简化建立了相关物理模型,进行了相应的算式推导和化简,运用MATLAB软件进行了编程和运算模拟。结果表明,空心乳液的内外径的大小与乳液的遮盖性能相关。更多还原

【Abstract】 Hollow is a special core-shell latex emulsion, generally it refers to prepared by emulsion polymerization with a cavity inside .Because of the hollow latex hollow structure, it has very different refractive index of light between shell polymer and the air cavity , scattering of incident light can be effective, which has a good covering effect and excellent whiteness. Multiple emulsion as an alternative to the current titanium hollow white plastic pigment used in paint, water-based inks, the field of low-weight coated paper. Moreover micro-capsules are also used as materials and UV additives. Since its inception in the eighties of last century, a good prospect of hollow latex aroused extensive attention.Semi-continuous dropping method was adopted to prepare hollow latex particles with moderate size and enough rigidity. Methyl methacrylate (MMA), butyl acrylate and methacrylic acid (MAA) were first copolymerized as seed latexes, and then MMA, MAA and divinyl benzene (DVB) were carried out to prepare hydrophilic carboxylated core latex particles consequently. On the basis of the core latex, the hydrophobic shell was then formed with styrene, MMA and DVB. Finally, the hollow emulsion were obtained by alkalization treatment of the core-shell latex particles. The effects of reaction temperature, MAA, emulsifier, cross-linked monomer, core/shell ratio and alkali treating on the emulsion stability and morphologies of hollow latex were investigated. The morphologies and particle sizes of hollow latex particles were characterized by TEM. The results show that the structure and properties of hollow emulsion is effected by the diameter and number of seeding emulsion, dosages of core/shell monomer, alkali treating, when core/shell ratio was 1:8, and counteract degree was 40%, the covering performance of hollow emulsion was the best and if it was more than the condition, covering power was going down. Meanwhile, the buildup of shell monomer also affects covering power greatly, when MAA mass ratio between seed monomer and core monomer is 28% and BA/ St mass ratio is 1/10, whiteness reaches tiptop, which is 94.40.In order to study the relationship between the performance of hollow emulsion structure and hiding power.This paper takes the Mie scattering theory , and simplified through the establishment of reasonable assumptions related to the physical model for the corresponding formula derivation and simplification, the use of MATLAB software programming and operation simulations. The results showed that the inner diameter of the hollow latex emulsion covering the size and performance-related.更多还原