氧化硅纳米材料的制备与表征

发布时间：2018-06-17 11:38

本文选题：氧化硅纳米材料 + 醇解法　；参考：《吉林大学》2016年硕士论文

【摘要】：近年来,氧化硅纳米材料成为纳米材料中的研究热点和重点。氧化硅纳米材料在各个领域都有着广泛的应用,例如医学、催化、国防军事等。制备更小、分散性更好及特殊形貌的氧化硅纳米材料吸引着广泛的研究兴趣。制备氧化硅纳米材料的研究,主要分干法和湿法两大类。这些方法中,溶胶凝胶法的优点是可以制备纯度高的产物,但产物粒径较大;气相法制备的氧化硅纳米材料分散性好、纯度高、表面羟基少,缺点是成本高、技术复杂、能量消耗大、不适宜大量生产。现有文献中提到的所制备的氧化硅纳米颗粒的粒径最小可达到5 nm,由化学沉淀法制备得到。粒径尺寸达到10 nm以下的氧化硅纳米材料具有更好的生物兼容性。但一般涉及复杂的制备过程,条件要求高。本论文所述的氧化硅制备方法简单,产品纯度高,产量大,反应所需的原材料价格低廉,适合大量生产。主要研究结果如下:(1)以正硅酸乙酯(TEOS)为硅源,以油酸为溶剂,分别与甲醇、乙醇、正丙醇、异丙醇在不同条件下进行反应,生成氧化硅粉体。通过XRD,TEM等技术对所制备的样品进行表征,所得到的样品主要为由球形纳米氧化硅团聚而成的链状结构。当前驱物为乙醇,反应时间为24 h时,所得到的样品为尺寸均一的纳米球状氧化硅,且分散性极好,没有团聚,粒径在500 nm左右。(2)研究发现,所用醇的种类及反应时间的不同均会影响所得到的氧化硅纳/微米球体的粒径。当以用异丙醇提供羟基时,所制备的氧化硅粉体的粒径最小,在20 nm~40 nm之间。以甲醇为前驱物时,所制备的氧化硅粉体的粒径最大,在0.5μm~1.5μm之间。(3)在不改变前驱物的条件下,研究发现,反应时间对样品的形貌也有影响。随着反应时间的增加,所得到的样品粒径呈现出先增大后减小的趋势。当前驱物为甲醇时,反应时间为24 h所得到的样品粒径最大,约为1.5μm;当前驱物为异丙醇时,反应时间为48 h所得到的样品粒径最大,约为40 nm。这是由于在反应时间较短时,由醇提供羟基。随着反应时间增加,醇与TEOS发生反应,样品粒径逐渐增加。当醇被大量消耗后,随着反应时间进一步增加,以溶剂油酸与产物发生的反应为主,所以样品粒径减小。(4)为研究表面活性剂的作用,进行了同等条件下加入表面活性剂十二烷基苯磺酸钠(SDBS)的对比试验。实验结果表明,该种表面活性剂可以使所得到的氧化硅表面更平滑。在以无水乙醇为前驱物,反应时间为24 h的对比实验中,得到的样品为由纳米氧化硅球体团聚而成的纳米链状结构。(5)四氯化硅(Si Cl4)是有机硅工业中常见的有毒废料。本论文以Si Cl4为硅源,制备无毒的氧化硅纳米材料。分别用不同醇(乙醇、正丙醇、异丙醇)作为前驱物,并改变反应时间,对不同醇以及反应时间对样品形貌的作用进行研究。以Si Cl4为硅源所制备的样品粒径较大,在200 nm~2μm之间。随着醇的改变,样品粒径也随之变化,其中以用异丙醇提供羟基时样品粒径最小,约为200 nm,以乙醇为前驱物样品粒径最大,可达到2μm。其形貌也明显区别于以TEOS为硅源的样品,当前驱物为异丙醇时,所得到的样品为纳米链状结构,当前驱物为正丙醇时,样品尺寸明显增加,为纳米氧化硅球体。当前驱物为乙醇,反应时间为24 h时,样品为纳米片状氧化硅团聚而成的中空纳米球体。当反应时间增加后,样品为实心球体,且团聚现象严重。
[Abstract]:In recent years, silicon oxide nanomaterials have become the focus of research in nanomaterials. Silicon oxide nanomaterials have been widely used in various fields, such as medicine, catalysis, national defense and military. The preparation of silicon oxide nanomaterials with smaller preparation, better dispersivity and special morphologies has attracted wide research interest. In these two major categories, mainly dry and wet methods, the advantages of the sol-gel method are that the products with high purity can be prepared, but the size of the products is larger. The silica nanomaterials prepared by gas phase method have good dispersibility, high purity, and few surface hydroxyl groups. The disadvantages are high cost, complex technology, large energy consumption and unsuitable production. The minimum particle size of the prepared silicon oxide nanoparticles is up to 5 nm and is prepared by chemical precipitation. The silica nanomaterials with a size size of less than 10 nm have better biocompatibility. But the complex preparation process is generally involved, and the conditions are high. The preparation of silicon oxide described in this paper is simple and the product is simple. The main results are as follows: (1) the reaction between ethyl orthosilicate (TEOS) as silicon source and oleic acid as solvent, methanol, ethanol, propanol and isopropanol in different conditions to produce silica powders by XRD, TEM and so on. The sample is characterized by a chain like structure of spherical nano silicon oxide. The current drive is ethanol, when the reaction time is 24 h, the obtained sample is a homogeneous nanoscale silicon oxide, with excellent dispersion and no reunion, the particle size is in the left right of 500 nm. (2) the study found that the types of alcohol used and the reaction time were found. The particle size of the oxidized silicon nano / microsphere will be affected. When the hydroxyl group is provided with isopropanol, the particle size of the silica powders is the smallest, between 20 nm~40 nm. When methanol is used as a precursor, the size of the silica powder is the largest, between 0.5 and m~1.5 mu m. (3) study under the condition of not changing the precursor It is found that the reaction time has an influence on the morphology of the sample. With the increase of the reaction time, the particle size of the sample increases first and then decreases. When the current is methanol, the size of the sample with the reaction time of 24 h is the largest, about 1.5 mu m, and the particle size of the sample when the current is isopropanol and the reaction time is 48 h The maximum is about 40 nm., which is due to the supply of hydroxyl alcohol by alcohol at the short reaction time. As the reaction time increases, the alcohol and TEOS react with the particle size. When the alcohol is consumed, the reaction time is increased, the reaction of the solvent oil acid and the product is the main, so the sample size decreases. (4) the study of surface activity. The effect of the sex agent was carried out under the same condition as a contrast test on the addition of twelve alkyl benzene sulfonate (SDBS) with the surfactant. The results showed that the surface active agent could make the surface of the silicon oxide more smooth. In the contrast experiment with anhydrous ethanol as the precursor and the reaction time of 24 h, the sample obtained was the nano silicon oxide. (5) four silicon chloride (Si Cl4) is a common toxic waste in the organosilicon industry. This paper uses Si Cl4 as a silicon source to prepare non-toxic silica nanomaterials. Different alcohols (ethanol, propanol, isopropanol) are used as precursors, and the reaction time is changed, and the samples form different alcohols and reaction times. The size of the sample prepared by Si Cl4 as the silicon source is larger and between 200 nm~2 mu m. With the change of alcohol, the particle size also changes. In the case of isopropanol providing hydroxyl group, the size of the sample is the smallest, about 200 nm, and the size of the sample with ethanol as the precursor is the largest, and the morphology of the sample is 2 mu m. and the morphology is distincently different from TEOS. For the sample of silicon source, when the current drive is isopropanol, the sample is a nano chain structure. When the current drive is normal propanol, the size of the sample is increased obviously, it is a nanometer silicon oxide sphere. The current drive is ethanol, when the reaction time is 24 h, the sample is a hollow nanoscale sphere formed by the nanometallic silicon oxide. When the reaction time is increased, The sample is a solid sphere, and the agglomeration is serious.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB383.1

【参考文献】