聚乳酸/氧化锌柱撑皂石纳米复合材料制备与性能及结构表征

通过微波水解法制备了ZnO柱撑皂石,并以其为加工助剂制备了聚乳酸(PLA)/ZnO柱撑皂石纳米复合材料.通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、对ZnO柱撑皂石及PLA/ZnO柱撑皂石纳米复合材料的结构进行了表征,并对其力学性能和热稳定性能进行了测试.微观结构分析表明,ZnO柱撑皂石呈现剥离状,并均匀分散在PLA基质中.力学性能研究表明0.3%ZnO柱撑皂石的加入有助于改善PLA复合材料的断裂伸长率.SEM分析表明PLA复合材料的断面发生明显改变,表现良好韧性;DSC结果显示纳米ZnO柱撑皂石可以降低复合材料的玻璃化转变温度、结晶温度,有助于提高PLA复合材料的结晶度,与XRD分析相吻合;热重分析表明ZnO柱撑皂石可以提高PLA复合材料的热稳定性.测试结果表明,ZnO柱撑皂石在PLA基质中起到了异相成核的作用,促进了PLA基质的结晶.     

层柱人工水热合成皂石的制备与表征(英)

利用具有理想皂石结构的人工水热合成蒙皂石为层原料，通过与羟基聚合铝离子（[Al₁₃O₄(OH)₂₄(H₂O)₁₂]⁷⁺）交换反应合成得到了一种层柱粘土。实验对于该铝柱皂石进行了粉末XRD，FT-IR和TG-DTA表征。氮气吸附实验说明其高温活化（773K，2 h）产物具有很高的BET比表面（360 m²·g^-1）。相对于层柱蒙脱土，层柱皂石显示了更高的催化裂解性能和热稳定性。层柱皂石的异丙苯裂解转化率达到了65%；而层柱蒙脱土的转化率只有4%。这说明层材料的四面体取代对于层柱粘土Br?nsted酸位的形成具有重要的决定作用。氨程序升温脱附实验发现铝柱皂石在350～650 ℃区间具有较强的氨脱附量，表明层柱皂石具有层柱蒙脱土所没有的强酸中心。     

铝交联皂石的合成和表征及催化性能

用XRD、化学分析、IR、MASNMR、TPD等手段表征了合成皂石及其铝交联物的结构。结果表明:皂石的交联密度与四面体层电荷和交联条件(Al/土比)有关。在乙醇氨化反应中,交联皂石显示了较好的催化活性和选择性。皂石的交联密度与液相产物分布的关系表明层柱材料对此反应具有择形催化作用。醇氨化反应可能是在吸附态NH_3和气相醇分子间进行的。     

甲醇氨化反应中交联皂石的催化行为

层柱材料是具有规则孔结构且其表面酸性及孔结构可调变的固体酸催化剂.本文合成了皂石,并用十三聚铝羟基络离子(Al_(13))与其交联,在醇氨化反应中研究了此层柱材料孔结构及表面酸性与催化性能间的关系.     

合成皂石及其交联物在偏三甲苯歧化反应中的催化行为

以羟基铝低聚物与其交联制得柱撑皂石,并在偏三甲苯歧化反应中考察了它们的催化性能.结果表明,催化活性随柱撑皂石表面酸量增加而增加;四甲苯中均四甲苯和二甲苯中邻二甲苯的百分含量皆高于热力学平衡值.催化特性与柱撑皂石的柱密度相关.     

含铁镍皂石的合成与交联的研究

用水热法合成出铁皂石和铁镍皂石,用羟基铝作交联剂制备了交联粘土.经XRD、DTA、IR、TPR、Mssbauer谱和化学分析表征,证明铁进入了粘土层骨架,铝交联可能作用在四面体铁上.形成Al_p-O-Fe键.     

皂石的合成、表征及其催化性能

用水热法合成了皂石,并用羟基铝低聚物与其交联制得AICLS。用XRD、~(27)Al和~(29)Si MASNMR及吡啶吸附量表征其晶相、结构和表面酸性。合成产物的结晶度很高。皂石中T—O—T片内四面体层上铝量可由合成条件控制,表明交联密度的柱间距与铝量有关。在异丙苯裂解反应中,AICLS的活性高于皂石,但活性衰减较慢;样品的催化裂化活性与探针分子可抵达的强酸中心数有关。     

镓取代皂石的合成与交联的研究

以XRD、MAS NMR、IR和化学分析等方法研究了镓取代皂石及其羟基铝低聚物交联物。结果表明,Ga占据骨架四面体位置,影响四面体层电荷及Al柱的交联密度。交联物经焙烧后,Al柱与层形成Ga—O—Al_p键,实现了层与柱的交联,而Al_(13)基本结构不变。     

镓皂石的合成,交联及表征

用水热法合成了镓皂石，并用Ａｌ１３齐聚物进行交联。经ＸＲＤ，ＩＦ，ＭＡＳＮＭＲ和元素分析表征，结果显示镓存在于粘土层四面体骨架中，交联剂引入量与层四面体中镓含量有关。层与柱键合可能发生在ＧａＯ４四面体上。     

锌皂石的非水热合成与插层组装性能研究

以尿素为羟基缓释剂和pH值控制剂, 在常压和低于100 ℃的温和实验条件下, 用非水热法合成出了八面体片阳离子为Zn^2＋的皂石, 研究了原料的硅铝配比(n_Si/n_Al), 溶液pH值、晶化温度和晶化时间对锌皂石合成的影响, 利用XRD, TEM, IR等手段对样品进行了表征. 结果表明: 合成样品具有三八面体皂石结构; 在比较宽的投料范围内 (n_Si/n_Al＝5.67～19), 合成皂石的晶相和晶形无明显变化; 在初始pH＝6的体系中, 90 ℃晶化12.5 h即可获得结构完整、晶相单一的锌皂石; 非水热条件下, 锌皂石在a向和b向上择优生长, c向生长速度相对较慢; 另外, 利用层间域离子的可交换性和层板带电荷的相反性, 将带正电荷的类水滑石客体层板引入到带负电荷的皂石层间, 形成了c向上单个皂石主体层板与单个类水滑石客体层板交叉堆垛的结构方式.     

镁皂石的水热合成与表征研究

采用优化的水热合成法,在473K反应2h合成了具有优良长程有序性的2：1型三八面体蒙皂石(皂石)。XRD分析表明合成产物具有典型的皂石层状结构。TEM测试发现,不同温度下合成的皂石具有类似的形态,但其层状片大小随着合成温度的提高而增大。不同温度(423K,473K,523K,573K)下水热合成实验结果表明,473K是合成具有良好层状有序结构皂石的临界温度。不同层电荷合成皂石对于活性染料(MB)的等温吸附实验说明吸附过程包含离子交换和絮凝机理。相对于天然蒙脱石,合成皂石对于离子性染料具有更大的吸附容量和作用力。     

交联镓皂石表面酸性及催化性能的研究

用水热法合成出两种不同镓含量的镓皂石，并用羟基铝低聚物对其进行了交联。对其表面酸性的考察发现，样品的酸量随嫁含量的增加而增大；样品均含有Ｂ酸和Ｌ酸中心，交联样品的Ｂ酸中心比交联前少。对样品催化性能的研究发现，催化活性与镓含量及酸量呈顺变关系。     

Synthesis and Characterizations of Hydroxy-aluminum Cross-Linked Montmorillonite

Cross-linked montmorillonite was prepared by reacting homoionic sodium form of bentonite (Na-M) from Istenmezeje (Hungary) with high molecular weight polyhydroxy-aluminum complex. The complex was prepared by controlled hydrolysis of alumina macrocation. The intercalated clay (Na-Al-M) was thermally treated to convert the hydroxy cations to oxide pillars. The pillared products were characterized by X-ray powder diffraction (XRD), Fourie transform infrared spectroscopy (FTIR), (thermogravimetry (TG), differential thermal analysis (DTA) and thermal analysis-mass spectrometry (TA-MS) methods. The specific surface area as well as pore size and pore structure distribution of samples were measured by nitrogen, water and carbon tetrachloride adsorption, and the heat of immersion was also determined. The pillared products were characterized by d(001) reflections of 19 Å, which is stable even at 500°C. The interaction of polymer alumina caused several changes in the obtained FTIR spectra due to the formation of different new bonds. The rate of dehydroxylation of the pillared product is very moderate, the water release occurred in different temperature ranges according to TA-MS results. Dehydration starts at interfaces and at the wall of pores, occurring nearly with uniform rate at 250-500°C. DTA curve indicates the formation of a new phase at 950°C. The obtained surface area of the pillared product by nitrogen adsorption becomes larger (208 m2 g-1) with respect to the non pillared clay, which decreases less than 10% upto 700°C. The pillared sample has a definite pore structure, the quantity of micropores (0-40 Å) decreased with increasing of macropores (>1000 Å). The obtained domestic pillared montmorillonite possesses a high degree of thermal stability and may be used as adsorbent.     

聚合物调控氧化钛层柱蒙脱石的结构和性能研究

为了改善氧化钛层柱蒙脱石的结构性能,以长链聚合物-端氨基聚甲基环氧乙烷(PPO-D-2000)为结构调节剂,调控合成了聚合物-氧化钛层柱蒙脱石材料。采用X射线粉末衍射、红外、拉曼光谱、TG/DSC、TEM和BET等手段进行了结构表征。结果表明,相比于小分子量表面活性剂而言,长链聚合物不仅能显著提高氧化钛层柱蒙脱石中的二氧化钛含量,而且比表面积比单独氧化钛柱撑蒙脱石增加了约13%,达到241.52m2/g,尤其是孔径、孔体积等孔道结构参数增加一倍左右。将合成的柱撑蒙脱石材料应用于对水中甲基橙的吸附和光催化性能研究表明,聚合物的调控作用能提高氧化钛层柱蒙脱石的吸附能力,光催化效率也有所改善。因此,聚合物对优化无机层柱粘土材料结构、改善吸附和催化性能具有良好的调控作用,为发展环境催化材料提供了新的途径。     

Molecular simulation of adsorption and separation of mixtures of short linear alkanes in pillared layered materials at ambient temperature

Grand canonical Monte Carlo and configurational-bias Monte Carlo techniques are carried out to simulate the adsorption of ternary and quaternary mixtures of short linear alkanes, involving methane, ethane, propane, and n-butane, in pillared layered materials at ambient temperature, T=300 K. In the simulation, a pillared layered pore is modeled by a uniform distribution of pillars between two layered walls built by making two separate talc lamellas parallel each other with a given size of interlayer distance. The interaction between fluid molecules and two layered walls is measured by storing potentials calculated in advance at a series of grid points. The interaction between fluid molecules and pillars is also calculated by a site-to-site method. The potential model proposed in this work is proved to be effective because of the simulation result being good agreement with the experimental data for the adsorption of nitrogen at 77 K. Then, the adsorption isotherms of mixtures of short linear alkanes in pillared layered pores with three different porosities psi=0.98, 0.93 and 0.85, and three pore widths H=1.02, 1.70 and 2.38 nm at 300 K are obtained by taking advantage of the model. The simulation results tell us that the longer chain component is preferentially adsorbed at low pressures, and its adsorption increases and then decreases as the pressure increases while the shorter chain component is still adsorbed at high pressures. Moreover, the sorption selectivity of pillared layered materials for the longest chain component in alkane mixtures increases as the mole fraction of methane in the gas phase increases. The selectivity of pillared layered materials for the longest chain component in alkane mixtures also increases as the pore width decreases and the porosity increases.     

Preparation and characterization of manganese- and samarium-manganese-alumina pillared montmorillonites

A Na-montmorillonite was intercalated with manganese- and samarium-manganese-aluminium solutions. The pillared montmorillonites were characterized by X-ray diffraction and nitrogen adsorption. The presence of manganese and samarium-manganese citrates in the intercalation process modify the distance between the clay sheets and the microporous structure of the pillared montmorillonites.     

超临界甲烷在氯化锆层柱纳米材料中吸附的分子模拟

用巨正则MonteCarlo(GCMC)方法模拟了甲烷在氯化锆层柱材料中的吸附。模拟中,氯化锆层柱材料模型化为柱子均匀分布在层板间的层柱孔,非极性分子甲烷采用Lennard-Jones分子模型,层板墙采用Steele的10-4-3模型,流体分子与柱子的相互作用采用点-点(sitetosite)的方法计算。在高度理想化模型的基础上,引入交互作用参数kfw,建立了有效势能模型。通过实验数据确定交互作用参数kfw,从而使该模型能有效地表征流体与层板墙的相互作用。根据77K温度下氮气的实验吸附数据,确定了流体和层板墙间的交互相作用参数。然后用这个有效的参数kfw=0.65模拟了三个超临界温度下氯化锆层柱材料中甲烷的吸附情形,得到了它位的吸附等温线,局部密度分布以有流体分子在层柱微孔中的瞬时构象,并分析了温度对材料吸附性能的影响。结果表明GCMC方法是预测材料吸附性能的一种强有力的工具。