有机硅树脂表面修饰氢氧化镁复合材料的合成与应用

发布时间：2018-07-10 04:22

本文选题：表面改性 + 丙烯酸树脂　；参考：《兰州大学》2015年硕士论文

【摘要】：在聚合物材料的实际应用过程中,往聚合物基体中添加无机填料以降低聚合物材料的成本和改善材料的某一方面性能己经有很久的历史了。随着对无机纳米粒子的研究深入,已经证明由无机纳米粒子和有机聚合物构成的聚合物基纳米复合材料比起微米级的无机粒子复合聚合物材料表现出了更加优异的性能。然而无论无机粒子是以纳米级别还是微米级别填充进聚合物中,对复合材料性能影响至关重要的就是无机粒子在聚合物基体的团聚以及无机粒子与聚合物基体不相容问题。对无机粒子表面改性是解决上述两大问题的最常用方法。本论文着眼于工业微米级氢氧化镁的表面改性,将一系列有机硅改性的丙烯酸树脂作为微米级氢氧化镁的表面改性剂。主要工作内容由以下三个方面组成：首先我们探究用树脂改性氢氧化镁的可行性。我们用Y-甲基丙烯酰氧基丙基三甲氧基硅烷(KH--570)与丙烯酸酯类单体共聚成硅丙树脂。再将所得树脂在溶剂异丙醇条件下改性氢氧化镁。结果表明,硅丙树脂成功改性到了氢氧化镁表面,并且改性效率高达20%。经过改性,氢氧化镁颗粒的平均粒径从3微米减小到1微米以下,分散性更好,粒径分布更窄。我们证明了硅羟基与氢氧化镁的结合强度大于羧基。存在于树脂链段上过多的硅羟基会引起氢氧化镁的团聚。由改性氢氧化镁复合低密度聚乙烯材料的拉伸强度较未改性的氢氧化镁复合材料有明显提高。当改性用硅丙树脂中KH—570含量为20%时,所做复合材料的力学性能最佳,拉伸强度为8.80MPa。出于环保和工业化可行性的考虑,我们用水代替溶剂异丙醇,合成具有长烷基侧链的硅丙树脂改性氢氧化镁。在水性条件下改性成功。我们同样观察到树脂改性对氢氧化镁有细化作用。经过长烷基侧链的硅丙树脂改性的氢氧化镁在丙酮中的沉降时间最长。复合材料的力学性能随着硅丙树脂添加量的增加而上升。树脂添加量为20%时,材料力学性能最佳。为了避免在改性氢氧化镁的过程中氢氧化镁过度团聚,我们用硅丙树脂与二甲基二乙氧基硅烷共乳化成乳液,再改性氢氧化镁。当乳液添加量仅为5%时,氢氧化镁粒子平均粒径就细化至360nm。改性的氢氧化镁呈现规则的片层六边形结构。制备的复合材料的热稳定性和力学性能是在所有改性复合材料中最好的。乳液添加量为5%时,热稳定性最好,力学性能最好,拉伸强度达到10.10MPa。接近纯低密度聚乙烯的拉伸强度。
[Abstract]:In the practical application of polymer materials, it has a long history to add inorganic fillers to polymer matrix to reduce the cost of polymer materials and improve some aspects of properties of polymer materials. With the further study of inorganic nanoparticles, it has been proved that the polymer based nanocomposites composed of inorganic nanoparticles and organic polymers have better performance than those of micron scale inorganic particles composite polymer materials. However, no matter whether the inorganic particles are filled in the polymer with nanometer or micron level, the most important influence on the properties of the composites is the agglomeration of inorganic particles in the polymer matrix and the incompatibility of inorganic particles with the polymer matrix. Surface modification of inorganic particles is the most common method to solve the above two problems. In this paper, a series of organosilicon modified acrylic resin was used as the surface modifier of micrometer magnesium hydroxide. The main work consists of the following three aspects: first, we explore the feasibility of resin modified magnesium hydroxide. The acrylic resin was synthesized by copolymerization of Y- methacryloxy propyl trimethoxy silane (KH-570) with acrylate monomer. Then the resin was modified with magnesium hydroxide under the condition of isopropanol. The results showed that silicone acrylic resin was successfully modified to the surface of magnesium hydroxide, and the modification efficiency was as high as 20%. After modification, the average particle size of magnesium hydroxide decreased from 3 micron to less than 1 micron, the dispersion was better and the particle size distribution was narrower. We have proved that the bonding strength of hydroxyl silicon with magnesium hydroxide is greater than that of carboxyl group. Excessive silica hydroxyl groups in the resin chain can cause agglomeration of magnesium hydroxide. The tensile strength of the modified magnesium hydroxide composite low density polyethylene is obviously higher than that of the unmodified magnesium hydroxide composite. When the content of KH-570 in the modified silicone resin is 20, the mechanical properties of the composites are the best and the tensile strength is 8.80 MPA. Considering the feasibility of environmental protection and industrialization, we used water instead of isopropanol to synthesize magnesium hydroxide modified by silicone acrylic resin with long alkyl side chain. It was successfully modified under water condition. We also observed that the modified resin has fine effect on magnesium hydroxide. Magnesium hydroxide modified by long alkyl side chain silica resin has the longest settling time in acetone. The mechanical properties of the composites increased with the increase of silicone acrylic resin content. When the resin content is 20, the mechanical properties of the material are the best. In order to avoid excessive agglomeration of magnesium hydroxide in the process of modification of magnesium hydroxide, the emulsion was co-emulsified with silicone acrylic resin and dimethyl diethoxy silane, and then modified with magnesium hydroxide. When the emulsion content is only 5, the average particle size of magnesium hydroxide particles is reduced to 360 nm. The modified magnesium hydroxide presents a regular hexagonal structure. The thermal stability and mechanical properties of the composites are the best among all the modified composites. When the emulsion content is 5, the thermal stability is the best, the mechanical property is the best, and the tensile strength is 10.10 MPA. Close to the tensile strength of pure low density polyethylene.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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