【作者】 王燕萍；

【导师】 颜德岳；

【作者基本信息】 上海交通大学 ， 材料学， 2009， 博士

【摘要】 介孔材料和超支化聚合物是近二十年来化学和材料学研究的热点领域。介孔材料具有高比表面积、大孔道容量、孔径在2.0～50.0 nm之间由合成条件任意调节等结构特征,从而赋予其许多独特的性能,在多相催化、传感器、吸附与分离等众多领域具有潜在的应用价值。超支化聚合物具有较好的流动性、良好的溶解性、大量的末端官能团等特点,且合成简单,使其在表面修饰、聚合物加工、生物医药、吸附等领域具有广泛的应用前景。本文结合介孔材料和超支化聚合物的相关特性,将超支化聚合物应用于介孔二氧化硅的制备和改性。论文实验工作从三个方面展开,共四章。第二章和第三章利用双亲性超支化共聚醚的自组装性能,以其作为模板,成功制备了介孔二氧化硅;第四章在常规介孔二氧化硅上接枝超支化聚砜胺,研究了其在酸性染料吸附中的应用;第五章将介孔材料的制备和改性相结合,以超支化聚砜胺作为模板制备了介孔二氧化硅,以共缩合法在介孔二氧化硅的制备过程中将超支化聚砜胺直接接枝在介孔二氧化硅中,并用于酸性染料的吸附。具体的研究内容和主要结论如下:1.基于弱两亲性的超支化PEHO-star-PPO的介孔二氧化硅的制备及表征采用活性阳离子开环聚合法制备了以憎水性超支化PEHO为核、弱亲水性PPO为臂的共聚醚。由于PEHO-star-PPO是具有弱亲水性的两亲性超支化共聚醚,难以在水中直接形成胶束,因此引入了共溶剂。利用超支化PEHO-star-PPO作为模板剂,在共溶剂和选择性溶剂体系中,以TEOS作为硅源,成功制备了孔径均一的介孔材料。在该体系中,起模板作用的是PEHO-star-PPO在共溶剂/选择性溶剂体系中形成的组装体,因而能够通过改变组装体尺寸的因素来调控所制备介孔二氧化硅的介孔尺寸。可采用三种方法对这种介孔二氧化硅的孔径进行调节:(1)通过调节超支化PEHO-star-PPO中PO和EHO的摩尔比,可改变所制备介孔材料的孔径。当超支化共聚醚中PO的比例增加时,导致聚集体尺寸变小,相应的介孔材料的孔径随之变小。(2)改变共溶剂和选择性溶剂的体积比,将改变组装体的尺寸,对介孔材料的孔径造成很大的影响。当甲醇或乙醇用作共溶剂,水用作选择性溶剂,提高水/醇的体积比,所制备的介孔材料的孔径大幅度增加。(3)共溶剂的极性对所制备的材料的孔径有十分重要的影响。当DMSO和丙酮用作共溶剂时,所制备的介孔材料的氮气吸附-脱附曲线呈H2型滞后环,所制备材料的介孔尺寸较小;而当甲醇和乙醇作共溶剂时,所制备介孔材料的氮气吸附-脱附曲线呈H1型滞后环,所制备材料的介孔尺寸较大。2.基于两亲性超支化PEHO-star-PPO的介孔二氧化硅的制备及表征采用活性阳离子开环聚合法制备了以憎水性超支化PEHO为核、亲水性PEO为臂的共聚醚。超支化PEHO-star-PEO是一种两亲性超支化共聚醚,在水中直接形成胶束。本章利用超支化PEHO-star-PEO作为模板剂,以TEOS作为硅源,成功制备了介孔二氧化硅。模板剂的去除可以通过煅烧或溶剂抽提来实现。由于PEHO-star-PEO结构的不均一性,导致以其为模板而制备的介孔二氧化硅的孔径大小不一,分布较宽。在该体系中,起模板作用的是PEHO-star-PEO形成的组装体或单分子胶束,因而能够通过改变组装体尺寸控制因素调节所制备介孔二氧化硅的介孔尺寸。可采用三种方法对这种介孔二氧化硅的孔径进行调节:(1)通过改变合成体系的温度来调节介孔二氧化硅的孔径。随着体系合成温度的上升,胶束中嵌段共聚物的聚集数增加,而且亲水链段的憎水性有所加强,两者共同作用造成胶束的增大,因而以胶束为模板制备的介孔材料孔径随之增大。(2)加入扩孔剂来扩大所制备材料的介孔孔径。少量三甲苯的加入可大大增加介孔二氧化硅的孔径。(3)溶剂对所制备材料的孔径有十分重要的影响。当水用作溶剂时,所制备的介孔二氧化硅的氮气吸附-脱附曲线呈H3型滞后环,制备的介孔尺寸较大,起作用的模板剂为PEHO-star-PEO的组装体;而当丙酮用作溶剂时,所制备介孔材料的氮气吸附-脱附曲线呈H2型滞后环,所制备材料的介孔尺寸较小,其介孔大小与单分子胶束大小相符。3. SBA-15接枝超支化聚砜胺及其在酸性染料吸附中的应用利用线型两亲性共聚物PEO-PPO-PEO合成了介孔二氧化硅SBA-15,通过硅烷偶联剂首先将胺丙基引入到SBA-15的内外表面,使其与二乙烯基砜和胺乙基哌嗪进一步反应,将超支化聚砜胺接枝到介孔二氧化硅表面。对改性前后的介孔材料进行了系统的表征,发现超支化聚砜胺的接枝并未改变孔洞的有序结构,但孔径、比表面积和孔容有所减小。研究了改性前后的介孔二氧化硅对山德兰红的吸附作用,并与活性炭的吸附作了比较,超支化聚砜胺接枝的介孔二氧化硅的最大吸附量可达活性炭的3.3～4.7倍,其吸附复合符合Langmuir方程,吸附动力学可用拟二级动力学方程解释,可以认为吸附主要是单分子层吸附。超支化聚砜胺的接枝量、染料溶液的pH值和温度对SBA-HPSA吸附染料的平衡吸附量有一定的影响。4.超支化聚砜胺/介孔二氧化硅杂化材料的制备和表征采用超支化聚砜胺为模板剂制备了聚砜胺/二氧化硅杂化材料,对杂化材料与煅烧后的无机物进行了测试和分析,发现杂化体内的聚砜胺含量约为25.5%,以聚砜胺为模板可制备介孔二氧化硅。在此基础上,采用“one-spot”法在杂化时引入了胺丙基三乙氧基硅烷,在形成聚砜胺/二氧化硅杂化材料的同时,将超支化聚砜胺直接接枝在二氧化硅的内外表面,对这种改性杂化材料的结构和吸附酸性染料的性能进行了分析。测试结果表明,改性杂化材料对酸性染料的吸附能力远高于活性炭,其最大吸附量可达活性炭的3倍。更多还原

【Abstract】 Mesoporous materials and hyperbranched polymers have attracted increasing attention in chemistry and material science since 1990’s. Mesoporous materials have unique structure, such as extremely high surface area, large pore volume, tunable pore size from 2 to 50 nm and versatile possibilities of surface functionalization. Therefore, they have potential application in catalysis, sensors, adsorption and separation. On the other hand, hyperbranched polymers possess some advantages such as low viscosity, good solubility, plentiful of terminal functional groups. Hyperbranched polymers can be prepared easily so that they have emerging application in surface modification, polymer processing, medicine, adsorption and nanotechnology. This dissertation focused on the preparation and modification of mesoporous silica based on hyperbranched polymer, which consisted of three primary parts. The second and third chapters described the preparation of mesoporous silica by the template of amphiphilic hyperbranched polymer self-assemblies. The fourth chapter paid attention to the modification of mesoporous silica with hyperbranched poly(sulfone-amine) and its application in acid dye removal. The fifth chapter concentrated on the preparation of mesoporous silica by the template of poly(sulfone-amine) and its direct simultaneous hypergrafting. The main results and conclusions are described as follows:1. Preparation and characterization of mesoporous silica by the template of poor amphiphilic hyperbranched PEHO-star-PPOAmphiphilic hyperbranched multiarm copolyethers with hydrophobic hyperbranched PEHO cores and linear poor hydrophilic PPO arms were synthesized by cationic ring-opening polymerization. The PEHO-star-PPO is difficult to self-aggregate directly in water due to poor hydrophilicity of PPO arms and hydrophobicity of hyperbranched PEHO cores. Therefore, hyperbranched copolyethers were dissolved in cosolvent and selective solvent for PEHO cores and PPO arms. Mesoporous silica was prepared successfully by the template of PEHO-star-PPO with TEOS as silica source in cosolvent and deoined water. DLS and nitrogen adsorption/desorption isotherms showed that the real structure-directing agent was the self-assemblies of amphiphilic PEHO-star-PPO. As a result, the aggregate size had an important influence on the mesoporous diameter. Three strategies had been used to adjust the mesoporous size: (1) Mesoporous size decreased with increasing of lipophile-hydrophile ratio (the molar ratio of PPO arms to PEHO cores) in the hyperbranched copolyethers template. (2) The volume ratio of selective solvent to cosolvent had great influence on the aggregate size and consequently had effect on the mesoporous size. Mesoporous size increased rapidly with the increasing of water volume ratio in ethanol/methanol and water mixed solvent. (3) The polarity of cosolvent had great effect on the mesopore. When DMSO or acetone as cosolvent, the adsorption/desorption showed H2 hysteresis loop and mesoporous size was small. However, the adsorption/desorption showed H1 hysteresis loop and mesoporous size was much larger with methanol or ethanol as cosolvent.2. Preparation and characterization of mesoporous silica by the template of amphiphilic hyperbranched PEHO-star-PEOAmphiphilic hyperbranched multiarm copolyethers with hydrophobic hyperbranched PEHO cores and linear hydrophilic PEO arms were synthesized by cationic ring-opening polymerization. The PEHO-star-PEO was a typical amphiphilic hyperbranched copolyether and it could form micelles in water. Mesoporous silica was prepared successfully by the template of PEHO-star-PEO with TEOS as silica source. The pore size of as-synthesized mesoporous silica is uneven because of high polydisperse index. Nitrogen adsorption/desorption isotherms showed that the real structure-directing agent was the self-assemblies or unimolecular micelles of amphiphilic PEHO-star-PEO. As a result, the aggregate size had influence on the mesoporous diameter. Three strategies had been used to adjust the mesoporous size: (1) Higher temperature made micelles larger, therefore the pore size increased. (2) Pore-expanding agent, such as trimethylbenzene, could expand the pore size of mesoporous silica. (3) Solvent had effect on pore size of as-synthesized mesoporous silica. When water as solvent, the adsorption/desorption showed H3 hysteresis loop and mesoporous size was large. The real structure-directing agent was the self-assemblies of hyperbranched PEHO-star-PEO. However, the adsorption/desorption showed H2 hysteresis loop and mesoporous size was small with acetone as solvent. The mesoporous size was consistent with unimolecular micelles.3. Modified SBA-15 with hyperbranched poly(sulfone-amine) grafting and its adsorption capacity in acid dye removalMesoporous SBA-15 was synthesized by the template of linear amphiphilic PEO-PPO-PEO. Aminopropyl was anchored, and then hyperbranched poly(sulfone-amine) was grafted onto the SBA-15. The structure and morphology of unmodified and modified mesoporous silica were characterized by FTIR, 29Si CP/MAS NMR, TGA, elemental analysis, XRD, SEM, TEM and nitrogen adsorption/desorption isotherms. Hyperbranched poly(sulfone-amine) grafting did not change the order of mesopore. However, pore size, BET surface area and pore volume were reduced with modification. The adsorption behaviors of Sandolan Red on SBA-15 with and without modification were studied. The maximum adsorption capacity of SBA-15 with hyperbranched poly(sulfone-amine) grafting was 3.3-4.7 times as that of active carbon. The adsorption equilibrium data could be fitted well by the Langmuir adsorption isotherm model. It was then concluded that once a dye molecule occupied a site, no further adsorption could take place at that site and a saturation value was reached which corresponded to the completion of a monolayer. The adsorption process obeyed the pseudo-second-order model, indicating anionic dye had a very strong affinity on SBA-15 with hyperbranched poly(sulfone-amine) grafting. The effect of the experimental parameters, such as grafting content, temperature and solution pH was investigated through a number of batch adsorption experiments. It was found that the removal of acid dye increased with the increase in grafting content of hyperbranched polymer. Temperature and solution pH had effect on the adsorption capacity of Sandolan Red.4. Preparation, characterization and application in dye adsorption of hyperbranched poly(sulfone-amine)/mesoporous silica hybridsPoly(sulfone-amine)/mesoporous silica hybrids and their calcined silica were prepared and characterized. The hybrids had 25.5% poly(sulfone-amine), and the inorganic framework was mesoporous silica with 3.2 nm mesopore. Then, aminopropyltriethoxylsilane was introduced at the same time of hybrid. Hyperbranched poly(sulfone-amine) was grafting onto mesoporous silica with“one-spot”method. The adsorption behaviors of Sandolan Red on modified poly(sulfone-amine)/silica hybrids were studied. Their maximum adsorption capacity of Sandolan Red was 3 times as that of active carbon.更多还原