基于多重相互作用凝胶体系的构建和性能

发布时间：2018-01-25 11:43

本文关键词： 三元凝胶氢键主-客体作用杂化凝胶可聚合AuNPs 催化　出处：《中国科学技术大学》2017年硕士论文　论文类型：学位论文

【摘要】：凝胶是具有三维网状结构、富含液体的软物质材料。在目前已报道文献中,水凝胶的种类繁多,应用广泛。本论文致力于构建基于多重交联作用的水凝胶体系,从凝胶网络的交联机理和应用两方面对水凝胶进行有益探索,具体工作内容和结果分为以下两个部分:1)构建基于多重物理相互作用的三元水凝胶poly[acrylamide-co-2-(dimethylamino)ethyl methacrylate][P(AM-co-DMAEMA)]和 poly(vinyl alcohol)(PVA)和β-cyclodextrin(β-CD),其中以β-CD接枝的PVA作为超分子受体、以AM与DMAEMA的共聚物作为超分子授体,引入主客体作用;通过低温处理,引入PVA结晶的交联作用;各组分间固有的氢键对交联也有贡献。以傅立叶变换红外光谱(FTIR)研究了各组分间的氢键作用,二维核磁共振氢谱(2H NOESY)确认β-CD与DMAEMA侧基之间的主客体作用,X射线衍射(XRD)则反映出PVA组分在低温处理过程中结晶。综上所述,通过冷冻聚合制备凝胶,对凝胶进行冷冻-融化循环处理,结合流变性能测试和热失重分析,系统研究了体系中的各种相互作用对凝胶性能的影响。作为对比,我们构建了 P(AM-co-DMAEMA)/PVA//β-CD 三元凝胶和 P(AM-co-DMAEMA)/PVA 二元水凝胶,进一步揭示了各种相互作用对凝胶性能的贡献。PVA的结晶受体系中多重相互作用的限制,所以P(AM-co-DMAEMA)和PVA二元凝胶的机械性能最好。2)以DMAEMA为还原剂和单体,在室温下对HAuCl4进行还原,由此得到尺寸均匀分布的可聚合金纳米粒子(AuNPs)。以紫外-可见光谱(UV-Vis)与核磁共振氢谱(1HNMR)对AuNPs的反应过程进行了实时跟踪,确定了制备AuNPs的最佳反应条件。傅立叶变换红外光谱(FTIR)和热失重分析(TGA)证实了在AuNPs上DMAEMA单体的存在。在此基础上,我们分别制备了以可聚合的AuNPs交联和化学交联剂交联的两种单交联的杂化凝胶,以及两种交联作用结合的双交联凝胶,研究了杂化凝胶的催化性能。扫描电镜(SEM)和透射电镜(TEM)结果显示,双交联凝胶孔壁更厚,孔尺寸更小。受甲基橙结构的影响,经过多次催化循环后,以N,N'-亚甲基双丙烯酰胺和双甲基丙烯酸乙二醇酯化学交联的双交联凝胶的催化活性有所降低;以N.N'-双丙烯酰胱胺双交联凝胶中具有可还原基团,在催化过程中交联程度降低,促进了反应物向凝胶内部扩散,所以催化活性良好。单交联凝胶的交联程度低,有利于反应物向凝胶内部扩散,所以经过多次循环后仍然具有良好的催化活性。
[Abstract]:Gel is a kind of soft material with three-dimensional network structure and rich in liquid. There are many kinds of hydrogels and they are widely used in the literature. This paper is devoted to the construction of hydrogel system based on multiple cross-linking. This paper makes a beneficial exploration on hydrogel from the crosslinking mechanism and application of gel network. The specific work and results are divided into the following two parts: 1) A ternary hydrogel poly based on multiple physical interactions is constructed. [Acrylamide-co-2-(dimethylamino)ethyl methacrylate]. [) and poly(vinyl alcohol) and 尾 -cyclodextrin (尾 -CDD). The 尾 -CD grafted PVA was used as supramolecular receptor, and the copolymer of AM and DMAEMA was used as supramolecular donor to introduce host and guest interaction. The crosslinking effect of PVA crystallization was introduced through low temperature treatment. The inherent hydrogen bonds among the components also contributed to the cross-linking. The hydrogen bonding between the components was studied by Fourier transform infrared spectroscopy (FTIR). Two-dimensional nuclear magnetic resonance (1H-NMR) 2H NOESYS confirmed the host and guest interaction between 尾 -CD and the lateral base of DMAEMA. X-ray diffraction (XRD) showed that the PVA component crystallized in the process of low temperature treatment. In conclusion, gel was prepared by freezing polymerization, and the gel was treated by freeze-melting cycle. The effects of various interactions on gel properties were systematically studied by means of rheological test and thermogravimetric analysis. We have constructed the ternary gels of PAM-co-DMAEMAE / PVA / 尾 -CD and binary hydrogels of PVA / AM-co-DMAEMAA / PVA / PVA / 尾 -CD ternary gels. It is further revealed that the contribution of various interactions to gel properties. The crystallization of PVA is limited by the multiple interactions in the system. Therefore, the mechanical properties of DMAEMA and PVA binary gels were the best. 2) DMAEMA was used as reducing agent and monomer to reduce HAuCl4 at room temperature. The size distribution of polymerizable gold nanoparticles was obtained. UV-Visand 1HNMRs were obtained by UV-Visand 1HNMRs. The reaction process of AuNPs is tracked in real time. The optimum reaction conditions for the preparation of AuNPs were determined. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The existence of DMAEMA monomer on AuNPs was confirmed. We prepared two kinds of mono-crosslinked hybrid gels crosslinked by polymerizable AuNPs and crosslinked by chemical crosslinking agent, and two kinds of cross-linked gels combined with crosslinking respectively. The catalytic properties of hybrid gels were studied. The results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the pore wall of double crosslinked gel was thicker and the pore size was smaller, which was influenced by the structure of methyl orange. After several catalytic cycles, the catalytic activity of the bicrosslinked gels which were chemically crosslinked with N- Na-methylene bisacrylamide and ethylene glycol dimethacrylate was decreased. The reducible group was found in the N (N) -diacrylyl cysteine (N) -diacryloyl cysteamine (BAC) cross-linked gel, which decreased the cross-linking degree during the catalytic process and promoted the diffusion of reactants to the gel. Therefore, the catalytic activity is good, and the crosslinking degree of single crosslinked gel is low, which is beneficial to the diffusion of reactants into the gel, so it still has good catalytic activity after many cycles.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O648.17

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