本文選題：St(?)ber法 + 四丁基氫氧化銨��； 參考：《吉林大學(xué)》2017年碩士論文

【摘要】：二氧化硅(SiO_2)粒子具有優(yōu)良的化學(xué)穩(wěn)定性和生物相容性,近年來在工業(yè)催化、生物成像、臨床檢驗等領(lǐng)域展現(xiàn)了廣闊的應(yīng)用前景,是目前研究者最關(guān)注的粒子體系之一。目前,二氧化硅粒子的制備多采用St(?)ber法,即在乙醇/水混合溶劑中,以氨水為催化劑,正硅酸四乙酯(TEOS)為硅源,通過一系列水解/縮合過程而獲得SiO_2粒子。然而,目前對于St(?)ber法中水解/縮合平衡的變化規(guī)律與SiO_2生長機制及其微結(jié)構(gòu)聯(lián)系的研究仍處于初級階段,在粒子尺寸及形貌調(diào)控,尤其是制備小尺寸(10 nm)以及非球形SiO_2粒子方面仍較為困難。因此,本論文主要研究了二氧化硅(SiO_2)粒子的可控合成。通過向經(jīng)典的St(?)ber體系中引入有機強堿四丁基氫氧化銨(TBAOH)作為助催化劑,系統(tǒng)研究了TBAOH對體系中TEOS水解/縮合過程的影響,并以此為基礎(chǔ)調(diào)控SiO_2粒子的尺寸與形貌,實現(xiàn)了小尺寸(10 nm)及非球形SiO_2粒子的可控制備。主要的工作內(nèi)容包括:1.在St(?)ber法制備SiO_2粒子的研究基礎(chǔ)上,加入TBAOH作為助催化劑,TBAOH是一種有機強堿,其電離的OH-和TBA+均會對SiO_2的成核生長過程產(chǎn)生一定的影響。OH-促進(jìn)了TEOS的水解縮合速率,增加了成“核”量,從而抑制初級粒子的聚合生長,TBA+濃度的提高則增加了離子強度,從而促進(jìn)粒子的聚集生長,本論文利用這一機理,通過調(diào)整助催化劑TABOH的濃度,制備了一種尺寸可調(diào)、穩(wěn)定分散的小尺寸SiO_2粒子(6-35 nm),并通過電導(dǎo)率,紅外光譜研究了不同濃度TBAOH對SiO_2成核生長過程的影響。固定NH3·H2O濃度為0.3 M,當(dāng)助催化劑TBAOH的濃度分別為0,0.2,0.4,0.6,0.8,1.0,2.0 m M時,制備的SiO_2粒子尺寸分別為10,28,35,27,20,16,6 nm;實驗結(jié)果表明,隨著進(jìn)一步增加TBAOH濃度,粒子的尺寸先增大而后減小,當(dāng)TBAOH濃度為0.4 m M時,獲得的SiO_2粒子尺寸最大(35 nm),當(dāng)TBAOH濃度為2.0 m M時,獲得的SiO_2粒子尺寸最小(6 nm)。透射電鏡以及動態(tài)光散射結(jié)果表明,利用這種方法制備的SiO_2粒子具有良好的單分散性,可與傳統(tǒng)的St(?)ber法相比擬。2.利用TBAOH先催化TEOS反應(yīng)一段時間后(預(yù)水解過程),在體系中補加NH3·H2O繼續(xù)反應(yīng),制備出非球形的SiO_2粒子。通過改變NH3·H2O濃度,調(diào)控SiO_2粒子的尺寸,粒子尺寸隨NH3·H2O濃度升高而變大,隨NH3·H2O濃度降低而變小。在NH3·H2O濃度一定的情況下,通過改變預(yù)水解時間,調(diào)控SiO_2粒子的形貌。實驗結(jié)果表明:當(dāng)預(yù)水解時間分別為0,20,40,60,90,120,150 min,獲得的花生狀SiO_2粒子,其長徑比分別為1.00,1.06,1.58,1.84,3.06,5.17,6.82。隨著延長預(yù)水解時間,粒子長徑比逐漸增大。預(yù)水解時間越長,TEOS水解越完全,體系內(nèi)成“核”數(shù)越多,越容易聚集,從而獲得不同尺寸的非球形SiO_2粒子。
[Abstract]:Silicon dioxide (SiO_2) particles have excellent chemical stability and biocompatibility. In recent years, it has been widely used in the fields of industrial catalysis, bioimaging, clinical testing and other fields, and is one of the most concerned particle systems. At present, the preparation of silica particles is mostly used in the St (?) BER method, that is, in the ethanol / water mixed solvent. With ammonia as the catalyst and four ethyl orthosilicate (TEOS) as the silicon source, SiO_2 particles are obtained by a series of hydrolysis / condensation processes. However, the study on the change of the hydrolysis / condensation equilibrium in the St (?) ber method and the relationship between the SiO_2 growth mechanism and the microstructure of the SiO_2 is still in the primary stage, and the particle size and morphology control, especially the preparation, is made. Small size (10 nm) and non spherical SiO_2 particles are still relatively difficult. Therefore, this paper mainly studies the controllable synthesis of silica (SiO_2) particles. By introducing organic strong alkali and four Butyl Ammonium Hydroxide (TBAOH) into the classical St (?) ber system as a co catalyst, the effect of TBAOH on the hydrolysis / condensation of TEOS in the system is systematically studied. Ringing and controlling the size and morphology of SiO_2 particles on this basis, the controllable preparation of small size (10 nm) and non spherical SiO_2 particles is realized. The main work contents include: 1. on the basis of the study of SiO_2 particles in the St (?) ber method, TBAOH is added as a co catalyst, TBAOH is an organic strong base, and the ionized OH- and TBA+ will all be to SiO_2. The nucleation growth process has a certain effect on.OH-, which promotes the hydrolysis condensation rate of TEOS, increases the "nucleation" and inhibits the polymerization of primary particles. The increase of TBA+ concentration increases the ionic strength, thus promoting the aggregation and growth of the particles. This paper uses this mechanism to prepare the catalyst TABOH by adjusting the concentration of the catalyst. A small size SiO_2 particle (6-35 nm) with adjustable size and stable dispersion, and the influence of different concentrations of TBAOH on the nucleation process of SiO_2 by electrical conductivity and infrared spectroscopy. When the concentration of NH3. H2O is 0.3 M, and when the concentration of Co catalyst TBAOH is 0,0.2,0.4,0.6,0.8,1.0,2.0 m M, the size of the prepared SiO_2 particle is respectively 5,27,20,16,6 nm; the experimental results show that the size of the particle first increases and then decreases with the increase of TBAOH concentration. When the concentration of TBAOH is 0.4 m M, the size of the SiO_2 particle is the largest (35 nm). When the concentration of TBAOH is 2 m M, the size of the SiO_2 particle is the least (6). Transmission electron microscopy and dynamic light scattering results show that the use of this method is the use of this method. The prepared SiO_2 particles have good monodispersity, which can be compared with the traditional St (?) ber method..2. uses TBAOH to catalyze TEOS reaction for a period of time (pre hydrolysis process). The non spherical SiO_2 particles are prepared by adding NH3 H2O in the system. The size of the SiO_2 particles is regulated by changing the NH3 H2O concentration, and the particle size depends on the size of the particle size. The concentration of H2O increases and decreases with the decrease of NH3 H2O concentration. Under a certain concentration of NH3. H2O, the morphology of SiO_2 particles is regulated by changing the prehydrolysis time. The experimental results show that when the pre hydrolysis time is 0,20,40,60,90120150 min, the peanut like SiO_2 particles are obtained, and the ratio of the length to diameter is 1.00,1.06,1.58,1.84,3.06, respectively. The length to diameter ratio of 5.17,6.82. increases with the prolongation of prehydrolysis time. The longer the pre hydrolysis time is, the more complete the hydrolysis of TEOS, the more the number of nucleation in the system, the more easy to gather, thus obtaining different sizes of non spherical SiO_2 particles.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O613.72

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