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聚丙烯/层状硅酸盐纳米复合材料的制备、结构和性能 总被引:10,自引:0,他引:10
聚丙烯/层状硅酸盐纳米复合材料可通过丙烯单体插层聚合、聚丙烯溶液插层和聚丙烯熔融插层等方法制备,得到插层型或剥离型纳米复合材料,形成了与传统填充型聚合物复合材料不同的微观结构,其机械性能,热性能,阻隔性能和流变性能等明显提高,由于聚丙烯的非极性及层状硅酸盐纳米复合材料制备方法的特殊性,该研究具有一定的理论价值。 相似文献
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纳米硅胶多孔层毛细管气相色谱柱的原位溶胶-凝胶法制备及其应用 总被引:3,自引:0,他引:3
采用原位溶胶-凝胶法在毛细管内壁上合成出均匀的纳米硅胶多孔层,对纳米硅胶颗粒进行了形貌表征,同时考察了不同反应条件下合成的纳米硅胶的比表面积、孔容和孔径的变化规律。先采用含氢硅油高温键合固化硅胶层,然后用无机盐淋洗钝化毛细管色谱柱,制备出纳米多孔层硅胶毛细管色谱柱。考察了所制备的纳米多孔层硅胶毛细管色谱柱对挥发性氟氯烃、水中氯代烃、含硫化合物以及低碳烃的分离特性。结果表明:所制备的纳米多孔层硅胶毛细管色谱柱具有良好的分离能力、一定的抗水性、稳定的色谱保留特性和良好的制柱重复性。 相似文献
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近年来有序交替的层状纳米结构薄膜的制备吸引了研究者们的极大关注. 目前, 这类薄膜的制备方法研究得最多的是LB技术[1~3]、基于化学吸附的自组装成膜技术[4,5]和交替沉积组装技术[6~8]. 但这几种方法都有明显的缺陷[9,10], 其中,通过LB技术制备有序交替层状纳米复合薄膜需要昂贵的仪器, 而且由于层间是分子相互作用, 膜的稳定性较差; 基于化学吸附的自组装成膜技术由于需要高反应活性的分子和特殊的基底表面, 并且由于化学反应的产率很难达到100%, 因此通过这种方法制备结构有序的多层膜并不容易; 利用交替沉积的方法制备出具有实用厚度的纳米多层膜需要耗费大量的时间. 最近, 出现了一种称为蒸发诱导的超分子自组装方法, 由这种方法制备的纳米多层膜具有成膜速度快和膜有序度高等优点, 此外还可以通过改变成膜物质浓度和拉膜速度来控制薄膜的厚度, 但与LB膜相比其厚度无法在分子水平上控制. 利用这种方法制备多层膜目前的文献报道仅限于线形SiO2与有机物的组装[10~13]. 本文利用这种方法制备了TiO2/十六烷基三甲基溴化铵纳米复合薄膜并对其结构进行了表征, 结果表明所制备的薄膜具有TiO2/十六烷基三甲基溴化铵有序交替的层状结构. 相似文献
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以氟碳表面活性剂全氟辛基磺酸钾为插层剂, 通过离子交换制备插层水滑石, 并以其为填料, 通过原位插层聚合方法, 制备了水滑石/氟碳表面活性剂/聚酰亚胺纳米复合材料. 用X射线衍射、 红外光谱和热失重等方法分析插层水滑石结构. 结果表明, 全氟辛基磺酸钾插层水滑石后, 水滑石的层间距由0.76 nm增加到2.52 nm, 在水滑石层间构建了氟碳链的微环境. 这种氟化水滑石可剥离分散于聚酰亚胺基体中, 改善了纳米复合材料的气体阻隔性能、 介电性能和机械性能. 这种影响不仅体现无机纳米片层的杂化效果, 而且展示出氟碳链的特点. 相似文献
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通过正离子交换将引发剂AIBA负载在蒙脱土上制得负载型引发剂V50-MMT.进而采用原位乳液聚合方法引发苯乙烯聚合制备PS/MMT纳米复合材料.采用XRD、TGA、DSC、TEM和抽提等方法对负载型引发剂和纳米复合材料进行了表征.结果表明,负载过程中引发剂AIBA进入了MMT的片层之间;聚合过程中介于片层间的引发剂因发生分解一方面产生自由基引发St聚合,另一方面MMT发生了剥离分散;由此法制备的PS/MMT纳米复合材料,MMT片层无规、均匀地分散于PS基体中,片层厚度在几个纳米至十几个纳米之间,长度为几十至几百个纳米不等;大量的PS链段以化学键接枝在MMT的片层上,接枝在MMT片层上的PS的分子量及其分布与游离的PS不同. 相似文献
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Qin Zheng YANG Chun Guang ZHANG De Jun SUN* Zhi Lin JIN Key Laboratory for Colloid & Interface Chemistry of Education Ministry Shandong University Jinan 《中国化学快报》2003,14(1)
Layered double hydroxides (LDHs), or the so-called hydrotalcite-like compounds, are important clay materials owing to their intercalation ability of anionic species and other physicochemical properties for application as anion adsorbents, medicine stabilizers, ion-exchangers, ionic conductors, catalysts and catalyst supports 1-2. The general formula is, [MⅡ1-x MⅢx(OH)2]x+ [Xm-x/m·nH2O]x-, abbreviated by: [MⅡ-MⅢ-X]. The net positive charge, due to substitution of trivalent by divale… 相似文献
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Venugopal BR Ravishankar N Perrey CR Shivakumara C Rajamathi M 《The journal of physical chemistry. B》2006,110(2):772-776
Layered double hydroxide (LDH)-monodispersed 4-nm CdSe nanoparticle composites were prepared through restacking of layers of colloidally dispersed delaminated LDH in the presence of CdSe nanoparticles in 1-butanol. The composites exhibit a blue shift for CdSe absorption, which increases with a decrease in nanoparticle content. The observed blue shift is due to the interaction of the quantum dots with the LDH layers, which leads to surface modification of the nanoparticles. 相似文献
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Mg-Al-NO_3层状双金属氢氧化物电性质研究 总被引:1,自引:0,他引:1
采用电泳法和电势滴定法测定出不同电解质(LiCl,NaCl和KCl)溶液中Mg-Al- NO_3层状双金属氢氧化物(Mg-Al-NO_3LDH)颗粒的ξ电位、等电点、永久电荷密 度以及零电荷点等电化学物理量,探讨了电解质、pH和样品化学组成对Mg-Al- NO_3LDH电性质的影响,研究发现一价阳离子Li~+,Na~+,K~+对Mg-Al-NO_3LDH颗粒 的等电点有影响,电荷点依次增大,而等电点依次降低。 相似文献
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Elastomer/LDH nanocomposites: Synthesis and studies on nanoparticle dispersion, mechanical properties and interfacial adhesion 总被引:1,自引:0,他引:1
Layered double hydroxides (LDHs) based elastomer nanocomposites have been synthesized and characterized in terms of nanoparticle dispersion, mechanical properties and interfacial adhesion. Since LDH has basic hydroxyl groups on its surface, its potential as reinforcing filler in elastomers and in additionally a crosslinking agent in carboxylated elastomers has been investigated in details. For this purpose, two different elastomers having widely different polarities and functional groups (e.g., ethylene propylene diene terpolymer, i.e. EPDM and carboxylated nitrile rubber, i.e. XNBR) have been used as the matrix. The pristine LDH based on Mg and Al was modified with decane sulfonate by the regeneration method. The morphological analysis of the nanocomposites (done by X-ray diffraction analysis and electron microscopy) shows that in both matrices LDH particles are dispersed in three different forms, i.e. as primary particles, as exfoliated layers and as soft clusters formed by both of them. However, their relative proportion differs drastically in the two matrices. We have shown in this study that the LDH can significantly improve the mechanical properties in both the system. In XNBR/LDH nanocomposites containing no conventional metal oxide curative, this improvement is very prominent due to secondary interaction between LDH and XNBR matrix indicating that LDH can crosslink carboxalated elastomers. It is also observed that LDH particle promotes strain-induced crystallization in XNBR/LDH. The fracture surface analysis shows that in XNBR/LDH nanocomposite very stable polymer-filler interface is formed and tensile failure takes place through the matrix rather than through the interface. In case of EPDM/LDH nanocomposites the opposite is observed and the polymer matrix hardly wets the surface of the LDH particle. 相似文献
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Biochemically functionalized silica nanoparticles 总被引:12,自引:0,他引:12
In this report, we demonstrate the biochemical modification of silica based nanoparticles. Both pure and dye-doped silica nanoparticles were prepared, and their surfaces were modified with enzymes and biocompatible chemical reagents that allow them to function as biosensors and biomarkers. The nanoparticles produced in this work are uniform in size with a 1.6% relative standard deviation. They have a pure silica surface and can thus be modified easily with many biomolecules for added biochemical functionality. Specifically, we have modified the nanoparticle surfaces with enzyme molecules (glutamate dehydrogenase (GDH) and lactate dehydrogenase (LDH)) and a biocompatible reagent for cell membrane staining. Experimental results show that the silica nanoparticles are a good biocompatible solid support for enzyme immobilization. The immobilized enzyme molecules on the nanoparticle surface have shown excellent enzymatic activity in their respective enzymatic reactions. The nanoparticle surface biochemical functionalization demonstrates the feasibility of using nanoparticles for biosensing and biomarking applications. 相似文献
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有机配体修饰纳米Al2O3的合成及性质研究 总被引:1,自引:0,他引:1
合成了以β-二酮配体3-甲基-1-苯基-4-(十八烷基酰基)吡唑啉酮-5(PMOP)修饰的Al2O3纳米粒子,并用IR、UV光谱、NMR和荧光光谱等手段进行了表征.修饰后的Al2O3纳米粒子能溶于氯仿、乙醇和甲苯等常见有机溶剂,并有较强的蓝色荧光.表明在一些无机纳米粒子的表面键合上有机配体后,可以产生新的光物理性质.修饰后的Al2O3纳米粒子还可作为支架材料用于准固态染料敏化纳米晶太阳能电池中. 相似文献
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Sheng-Ping Gao Tian-Hong Lu Shu-Ping Li Hui Zhong 《Colloids and surfaces. A, Physicochemical and engineering aspects》2009,351(1-3):26-29
The influence of zeta potential, altered by the pH value in synthesis, on the property of glutamic acid (Glu for short)/LDH compounds has been studied. It was found that the layer charges increased first then decreased as the pH value increased, and the layer charge had prominent effect on the properties of the samples. The crystallinity degree and the interlayer spacing increased gradually and the morphology changed from tubular or fibrous to platelet structure as the layer charge increased. And a model has been proposed to explain how pH values in the synthesis influence the LDH compound property by altering their layer charges. 相似文献
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合成了一种具有双光子荧光探针功能的有机纳米粒子2,5,2',5'-(4'-N,N-二苯胺苯乙烯基)联苯(DPA-TSB), 并研究其细胞毒性. 利用水溶性四氮唑(WST-1)法、 乳酸脱氮酶(LDH)法和流式细胞术检测了胃癌细胞吞噬纳米粒子后的生理活性. 研究结果表明, 在纳米粒子浓度小于12 μg/mL时, 胃癌细胞仍表现出较好的生理活性, 表明该纳米粒子是一种具有较好生物安全性的光功能有机纳米粒子. 相似文献
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As for the stabilization of chemically sensitive bioactive molecule in this study, gallic acid (GA) with antioxidant property was intercalated into interlayer space of layered double hydroxide (LDH), which was realized by exfoliation and reassembling reaction. At first, the pristine nitrate-type Zn2Al-LDH in solid state was synthesized via co-precipitation followed by the hydrothermal treatment at 80 °C for 6 h, and then exfoliated in formamide to form a colloidal solution of exfoliated LDH nanosheets, and finally reassembled in the presence of GA to prepare GA intercalated LDH (GA-LDH) desired, where the pH was adjusted to 8.0 in order to deprotonate GA to form gallate anion. According to the XRD analysis, GA-LDH showed well-developed (00l) diffraction peaks with a basal spacing of 1.15 nm, which was estimated to be larger than that of the pristine LDH (0.88 nm), indicating that gallate molecules were incorporated into LDH layers with perpendicular orientation. From the FT-IR spectra it was found that gallic acid was completely deprotonated into gallate, and stabilized in between LDH lattices via electrostatic interaction. The content of GA in GA-LDH was determined to be around 23 wt% by UV–vis spectroscopic study, which was also confirmed by HPLC analysis. According to the in-vitro release of GA out of GA-LDH in PBS solution (pH 7.4) at 4 °C, GA was sustainably released from GA-LDH nanohybrid up to 86% within 72 h. The antioxidant property of GA-LDH was almost the same with that of intact GA which was examined by DPPH. The photostability of GA-LDH under UV light irradiation was immensely enhanced compared to intact GA. It is, therefore, concluded that the present GA-LDH nanohybrid can be considered as an excellent antioxidant material with high chemical- and photo-stabilities, and controlled release property. 相似文献