聚苯乙烯模板法制备金属镍中空微球的研究

发布时间：2018-01-30 11:46

  本文关键词： 聚苯乙烯微球 化学镀 聚苯乙烯/镍 核壳结构 中空微球　出处：《济南大学》2011年硕士论文　论文类型：学位论文

【摘要】：随着纳米科学的发展,纳米多孔材料作为一个重要的研究方向,已经成为了材料科学研究的焦点。由于该多孔材料具有纳米级的孔径,大的孔隙率,显著的表面效应及高的比表面积,成为了一种新型的兼具功能和结构双重属性的性能优异的材料,被广泛地应用于环保清洁、高效节能等绿色材料,高效过滤及分离材料,燃料电池、消声、减振材料,电磁屏蔽性材料,催化材料等各个领域。目前制备金属纳米多孔材料的方法很多,主要有金属粉体烧结法、脱合金法、斜入射沉积法、胶体晶模板法等。本论文提出了一种新的方法制备有机/无机纳米复合材料及纳米金属中空微球,通过对实验条件的优化,分别制得了镀层均匀的纳米复合材料和孔径均一的中空微球。 本文首先采用微乳液聚合法制备了形貌可控的120 nm左右的聚苯乙烯微球,研究了单体用量、反应温度及引发剂、乳化剂用量对聚苯乙烯微球粒径及分布的影响,实验测得聚苯乙烯微球的平均粒径随单体用量和引发剂用量的增加而增大,随乳化剂浓度的增大和反应温度的升高而减小,实验室条件下测得制备聚苯乙烯微球的最佳配比条件为:单体苯乙烯10 mL,引发剂过硫酸钾0.25 g,乳化剂十二烷基磺酸钠0.4 g,反应介质水90 mL,水浴反应温度75℃,反应时间8 h;然后采用化学镀法,以聚苯乙烯微球为基体,分别用传统的有钯活化法和新的无钯活化工艺对其进行前处理,使聚苯乙烯微球表面植入催化活性中心,制备了具有可控壳层的镍包覆聚苯乙烯微球的核壳结构复合微球,优化了化学镀工艺,同时对两种方法所制备的复合微球进行SEM、EDS、红外光谱分析,由实验结果可得,与传统的有钯活化工艺镀镍法相比,无钯活化工艺镀镍法制得的PS/Ni复合微球分散性较好,且镀层较均匀、较厚;然后论文根据复合微球的分解温度范围,在500℃下保温5 h除去聚苯乙烯微球模板,制得了壁厚大约为15-20 nm,孔径为100-130 nm的中空微球,并研究了不同烧失温度对材料孔结构的影响,对最佳烧失温度下制得的纳米金属镍中空微球试样进行了X射线衍射分析和N2吸附-脱附分析,结果表明,纳米镍中空微球试样具有面心立方结构,且晶型很好,基本没有引进其他杂质,通过BET吸附测得纳米金属镍中空微球的比表面积为161.69 m~2·g~(-1)。论文选用液相催化加氢法,将制得的金属镍中空微球用于催化2,4-二甲基硝基苯加氢制备2,4-二甲基苯胺,结果表明,该多孔材料对2,4-二甲基硝基苯加氢反应有催化作用,但是选择性和催化活性均不理想,在实验室条件下,温度为50℃,压力为3.0 MPa,恒温反应120 min,测得2,4-二甲基苯胺的收率为46 %,并初步探讨了催化加氢反应机理。
[Abstract]:With the development of nanoscience, nano-porous materials, as an important research direction, have become the focus of material science, because the porous materials have nanometer pore size and large porosity. Because of its remarkable surface effect and high specific surface area, it has become a new type of material with dual properties of function and structure, which has been widely used in green materials such as environmental protection, clean, high efficiency and energy saving. High efficiency filtration and separation materials, fuel cells, noise suppression, vibration absorption materials, electromagnetic shielding materials, catalytic materials and other fields. At present, there are many methods to prepare metal nano-porous materials, mainly metal powder sintering method. In this paper, a new method was proposed to prepare organic / inorganic nanocomposites and nanometallic hollow microspheres by optimizing the experimental conditions. Nanocomposites with uniform coating and hollow microspheres with uniform pore size were prepared respectively. In this paper, polystyrene microspheres with controllable morphology were prepared by microemulsion polymerization. The amount of monomer, reaction temperature and initiator were studied. The effect of emulsifier dosage on the particle size and distribution of polystyrene microspheres was studied. The experimental results showed that the average particle size of polystyrene microspheres increased with the increase of the amount of monomer and initiator. With the increase of emulsifier concentration and reaction temperature, the optimum conditions for preparing polystyrene microspheres were determined as follows: monomer styrene 10 mL. The initiator potassium persulfate 0.25 g, emulsifier 12 alkyl sulfonate 0.4 g, reaction medium 90 mL water, water bath temperature 75 鈩，

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