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碳微球表面二苯并噻吩分子印迹聚合材料的制备及性能

Preparation and Properties of Dibenzothiophene Molecular Imprinted Polymer on the Surface of Carbon Microspheres

【作者】 郭明聪

【导师】 刘旭光;

【作者基本信息】 太原理工大学 , 应用化学, 2010, 硕士

【摘要】 分子印迹聚合物(MIP)是一种具有分子识别能力的新型高分子材料,由于它具有预定性、识别性和实用性三大特点,因此近年来发展非常迅速,已在分离、萃取、富集、酶模拟以及生物模拟传感器等领域展现出广泛的应用前景。本论文在碳微球(CMSs)制备基础上,对其表面进行化学修饰,然后经接枝、聚合、分子模板交联等步骤,得到一类对油品中二苯并噻吩化合物优先识别和吸附的新型表面分子印迹材料,此材料对油品的深度脱硫具有重要意义。本论文中,首先利用化学气相沉积法(CVD),分别以脱油沥青和乙炔为碳源制备了CMSs;然后对CMSs进行了KMnO4、KMnO4/HNO3、KMnO4/H2SO4化学修饰的研究,得到MnO2/CMSs复合物和氧化CMSs;最后初步探索了在CMSs表面接枝聚甲基丙烯酸(PMAA)和制备二苯并噻吩表面分子印迹聚合物。采用场发射扫描电子显微镜、高分辨透射电子显微镜、X-射线衍射分析、热重分析和红外分析等手段对产物进行表征和分析。结果如下:1. CVD法合成了直径约为350nm的CMSs,然后将CMSs进行了KMnO4、KMnO4/HNO3、KMnO4/H2SO4化学修饰,在CMSs的表面原位生成并包覆了MnO2,得到MnO2/CMSs复合材料,有望用于高效电容器;修饰后的CMSs用过量草酸进行洗涤,得到氧化CMSs,在水中分散效果较好,且在乙醇中也有一定分散性。氧化后CMSs的表面存在活性位点,达到了改善CMSs表面惰性的目的,为CMSs的进一步修饰奠定基础;2.在氧化CMSs的基础上,使用偶联剂γ-(甲基丙烯酰氧)丙基三甲氧基硅烷对氧化CMSs进行了表面化学改性,将双键引至CMSs表面;然后用热引发和光引发的方式,成功地将PMAA接枝到CMSs表面,为制备表面分子印迹材料奠定了实验和理论基础。3.以二苯并噻吩为模板分子、MAA为单体、氯仿为溶剂、偶氮二异丁腈为引发剂、二甲基丙烯酸乙二醇酯为交联剂,在CMSs表面制得了二苯并噻吩表面分子印迹材料。通过吸附实验测得此印迹材料达到吸附平衡的吸附时间为5h,吸附量为0.595mmol/g。与非印迹聚合物相比,MIP表现出对二苯并噻吩有较好的吸附性能,此MIP有望用于油品的深度脱硫。

【Abstract】 Molecularly imprinted polymer (MIP) is a new kind of macromolecular material with high molecular recognition characteristics. Owing to predetermined property with specific recognition capability and wide practicability, it has developed quickly in recent years, exhibiting extensive application potentials in separation, extraction, enrichment, enzyme mimic, biomimic sensor and other fields. In this paper, the surface chemical modification of carbon microspheres (CMSs) was firstly carried out. Then the new surface molecular imprinted materials with priority recognition and adsorption were gained through grafting, polymerization, and molecular template crosslinking steps. It is very important for deep desulfurization of oils.In this paper, first of all, CMSs were synthesized by chemical vapor deposition method (CVD), using deoiled asphalt and acetylene as carbon sources. Subsequently, the surface chemical modification of CMSs was carried out in KMnO4, the mixture of KMnO4 and HNO3, and the mixture of KMnO4 and H2SO4, and MnO2-coated CMSs and oxidized-CMSs were obtained separately. In addition, polymethyl acrylic acid (PMAA) was grafted onto the surface of modified-CMSs, and dibenzothiophene molecularly imprinted polymers on CMSs were prepared. The morphologies and surface microstructures of different products were characterized by field emission scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction, thermogravimetry and fourier transformation infra-red spectrometry. The results are as follows:1. CMSs with the diameter 350 nm were prepared by CVD. KMnO4, KMnO4/HNO3, KMnO4/H2SO4 solution were used to modify the CMSs. The obtained products were MnO2-coated CMSs particles. The MnO2/CMSs composites are expected to be efficient candidate for supercapacitor. And then H2C2O4 solution was used to wash MnO2-modified CMSs, forming oxidized CMSs. The oxidized CMSs had good dispersion in water and ethanol. After the CMSs were oxidized, some active sites were formed on the surface of CMSs, which was effective to change the inert nature of the surface of CMSs, thus laying the foundation for further modification.2. The oxidized CMSs were modified using the coupling agent 3-methacryloxypropyl trimethoxysilane, so as to introduce C=C bonds on the surface of CMSs. PMAA was grafted on the surface of CMSs by photo-initiating or thermal-initiating approach. This laid an experimental and theoretical foundation for the preparation of molecular imprinting materials.3. Surface molecular imprinting polymers were prepared on the surface of CMSs using dibenzothiophene as template, MAA as functional monomer, chloroform as solvent, azobisisobutyronitrile as initiator, ethylene glycol dimethacrylate as crosslinking agent. The adsorption behavior of MIP showed that the adsorption equilibrium time was about 5h and the adsorption amount was 0.595mmol/g. Compared with blank polymers, MIP possessed a better adsorption property toward dibenzothiophene, showing its portential for deep desulfurization.

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