共查询到20条相似文献,搜索用时 15 毫秒
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En-Rong Li Qian-Jun Zhang Wei Wang Qing-Wen Zhu Long Ba 《Frontiers of Materials Science in China》2010,4(1):52-56
Mesoporous silica nanospheres (MSNs) with regular pores have been fabricated using cetyltrimethylammonium bromide (CTAB) as surfactant in high pH solution. The average size of the MCM-41 silica nanospheres was reduced from 95 to 48 nm, while the concentration of CTAB increases from 7.7 to 11.5 mmol/L. Carbon black was deposited on MSNs using hexane as the carbon source. By mixing such materials with silicone rubber, the composites become conducting when equivalent carbon volume fraction is higher than a certain region, which is less sensitive to the morphology of the deposited carbon. The improved piezoresistance repeatability has been found on the composite sample of MSNs/carbon plus extra high conducting carbon black. The load and strain sensitive range up to 0.35 MPa and 0.10, respectively, with less resistance fluctuation during multiple press loading cycles. 相似文献
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Suk Bon Yoon Kuen-Woo Lee Jei-Kwon Moon Yong Suk Choi 《Journal of Experimental Nanoscience》2014,9(3):221-229
Hard template-based fabrication of mesoporous carbon unavoidably goes through the removal process of the template to generate template-free carbon replica, including troublesome disposal of template waste often accompanied by toxic etchant, which not only increases the fabrication cost of materials but also raises serious environmental concerns. As a novel strategy to overcome such problem, a direct in situ synthesis approach using silica waste in carbon/silica nanocomposite as a silica source and cetyltrimethylammonium bromide as a porogen under basic condition is reported in this study for the generation of a new composite composed of mesoporous MCM-41 silica and hollow carbon capsule. The resultant MCM-41/carbon capsule composite offers a 3-D interconnected multimodal pore system, which discloses a wide pore range of ordered uniform mesopores (ca 2.3?nm) resulting from MCM-41 silica and disordered uniform mesopores (ca 3.8?nm) and macropores (ca 300?nm) from hollow mesoporous carbon, respectively. The composite has a high specific surface area (ca 909?m2/g) and large pore volume (ca 0.73?cm3/g). The in situ transformation approach of silica waste into valuable mesoporous silica is considered as a promising scalable route for efficient new multi-functional composites useful for a wide range of applications such as adsorption of volatile organic compounds and radioactive wastes produced in a nuclear facility. 相似文献
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Precipitated silicas have been utilized successfully as rubber reinforcing fillers instead of carbon black. The development
of new mesoporous silicas with properties different than the precipitated silicas, specially their high BET surface areas
and their organized pore structures with pore sizes between 1.5–10 nm, make them potential materials in rubber reinforcing.
The knowledge of the interactions between rubber and its filler at a fundamental level is important to understand the physical
and mechanical properties of a filled rubber system. This paper presents a comparative microstructural analysis of the interactions
of the styrene butadiene rubber (SBR) with mesoporous silica and with Ultrasil VN3 silica, made on mixtures prepared in a
rheometer at 150 °C and their toluene extracted residues. Solid state nuclear magnetic resonance, Fourier transform infrared
(FTIR), thermogravimetry (TGA), scanning electron microscopy (SEM) and nitrogen adsorption isotherms, show a relation between
the strength of the interaction and the particle size and pore structure characteristics of the mesoporous materials. Such
a material prepared under certain specific conditions shows better interaction with the rubber than Ultrasil VN3 silica.
Electronic Publication 相似文献
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The polyaniline composition by silica based mesoporous hollow nanosphere (silica-HNS) was synthesized and selected as a promising solid support for palladium nanoparticle stabilization. Then the nanocomposite was applied as a nanocatalyst for aerobic benzyl alcohol oxidation reactions. Catalyst recyclability showed six successful runs for the reaction. TEM and SEM-EDX/mapping images were used to study the structure and morphology of the PdNPs@PANI/HNS. FT-IR spectroscopy, Thermal gravimetric analysis (TGA), and BET were used to characterize and investigate the catalyst nature. In addition, the amounts of Pd loading were characterized by ICP-AES technique. 相似文献
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介孔炭材料及介孔炭/氧化硅复合材料对大分子有机污染物的吸附 总被引:1,自引:0,他引:1
介孔炭材料与活性炭相比具有较大的孔体积和孔径,高的比表面积以及规则的孔道结构,而介孔炭/氧化硅复合材料兼顾了活性炭与介孔材料的优点,因此在吸附大分子有机污染物方面有很好的应用前景。笔者综述了近年来介孔炭,负载/修饰后的介孔炭,介孔炭/氧化硅复合材料的制备和最新研究进展。在制备方面,根据其制备机理的不同可分为硬模板法和软模板法,制备出有序的介孔炭与介孔炭/氧化硅复合材料。在应用方面,重点介绍了介孔炭材料和介孔炭/氧化硅复合材料对大分子有机污染物的吸附性能。进而对介孔炭/氧化硅复合材料在吸附方面的应用进行了展望。 相似文献
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Self-assembled natural rubber/silica nanocomposites: Its preparation and characterization 总被引:1,自引:0,他引:1
Zheng Peng Ling Xue Kong Si-Dong Li Yin Chen Mao Fang Huang 《Composites Science and Technology》2007,67(15-16):3130-3139
A novel natural rubber/silica (NR/SiO2) nanocomposite is developed by combining self-assembly and latex-compounding techniques. The results show that the SiO2 nanoparticles are homogenously distributed throughout NR matrix as nano-clusters with an average size ranged from 60 to 150 nm when the SiO2 loading is less than 6.5 wt%. At low SiO2 contents (4.0 wt%), the NR latex (NRL) and SiO2 particles are assembled as a core-shell structure by employing poly (diallyldimethylammonium chloride) (PDDA) as an inter-medium, and only primary aggregations of SiO2 are observed. When more SiO2 is loaded, secondary aggregations of SiO2 nanoparticles are gradually generated, and the size of SiO2 cluster dramatically increases. The thermal/thermooxidative resistance and mechanical properties of NR/SiO2 nanocomposites are compared to the NR host. The nanocomposites, particularly when the SiO2 nanoparticles are uniformly dispersed, possess significantly enhanced thermal resistance and mechanical properties, which are strongly depended on the morphology of nanocomposites. The NR/SiO2 has great potential to manufacture medical protective products with high performances. 相似文献
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制备了三相纳米复合材料SBR/ZDMA/气相法白炭黑。采用了两种气相法白炭黑,U—fumed silica是一种未改性的气相法白炭黑,M—fumed silica是一种采用硅烷偶联剂Si69表面改性的气相法白炭黑。主要研究了气相法白炭黑和ZDMA之间的协同补强效应。研究结果显示,单独添加同样份数的改性气相法白炭黑和未改性气相法白炭黑对硫化胶物理机械性能的影响不同,改性气相法白炭黑的效果明显优于未改性气相法白炭黑。单独添加气相法白炭黑,体系的物理机械性能仍然维持在较低值。当同时添加气相法白炭黑和ZDMA时,会观察到明显的协同补强效应。交联密度和丙酮抽出试验表明对气相法白炭黑进行表面改性和在体系中添加ZDMA均会减弱气相法白炭黑表面羟基的影响。扫描电镜显示改性后气相法白炭黑在SBR中的分散性得到提高。在体系中添加ZDMA会提高气相法白炭黑的分散性。 相似文献
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Electroactive response of mesoporous silica and its nanocomposites with conducting polymers 总被引:1,自引:0,他引:1
Electroactive response of suspensions of mesoporous silica and its nanocomposites with conducting polyaniline and copolyaniline inside its channels were examined under an electric field, mainly focusing on their rheological characteristics. Initially these conducting polymer/mesoporous silica nanocomposites were synthesized and their physical properties were studied by scanning electron microscopy, transmission electron microscopy and N2-adsorption isotherm. Then, mesoporous silica and its nanocomposites were dispersed in silicone oil as an electrorheological (ER) material. Typical ER behaviors of shear stress and shear viscosity curves as a function of electric field and shear rate were observed. Without an electric field, the suspensions behaved almost like a Newtonian fluid. However, under an electric field, their shear stresses increased with shear rate, demonstrating a yield stress. Compared with mesoporous silica and polyaniline, polyaniline/mesoporous silica-based ER fluid showed enhanced ER performance due to the anisotropic characteristics. In addition, it was found that a suggested shear stress model (Cho–Choi–Jhon model) well described the flow curves. 相似文献
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AbstractWe have developed composite hydrogels of chitosan (CS) and mesoporous silica nanoparticles (MSNs) in this study. The gelation rate, gel strength, drug delivery behavior and chondrocyte proliferation properties were investigated. The introduction of MSNs into CS accelerated the gelation process at body temperature and also increased the elastic modulus G′ from 1000 to 1800 Pa. When we used gentamicin (GS) and bovine serum albumin (BSA) as model small chemical drugs and biomacromolecules, respectively, the CS/MSN hydrogels released GS and BSA in a sustained manner simultaneously, but the CS hydrogels only showed sustained BSA release. Furthermore, in vitro chondrocyte culture showed that the CS/MSN composite hydrogels indeed performed much better in supporting chondrocyte growth and maintaining chondrocytic phenotype compared to the CS hydrogels. Therefore, the results suggest that the CS/MSN composite hydrogels can be potentially very useful for cartilage regeneration. 相似文献
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以一种松香基双季铵盐和CTAB为共混模板,正硅酸乙酯为硅源,通过调节两种表面活性剂的不同用量,在碱性条件下水解制备了SiA、SiB、SiC、SiD4种SiO2材料。采用TGA确定煅烧温度为550℃;SEM照片分析可知SiC、SiD的微观形貌优于SiA、SiB,且为分散均匀的球形颗粒,无团聚;TEM照片分析可知,SiC、SiD为具有介孔结构的球形颗粒;FT-IR确证了SiC、SiD煅烧前后的基本结构;经氮气吸附-脱附实验分析,结果表明,SiC、SiD的孔径主要集中在3.8nm处,比表面积和累积孔体积分别为685.29m2/g、1.22cm3/g和609.73m2/g、0.93cm3/g。 相似文献
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Liuding Wang Hongjing Wu Zhongyuan ShenShaoli Guo Yiming Wang 《Materials Science and Engineering: B》2012,177(18):1649-1654
We propose and demonstrate a new scheme to improve microwave absorption property through polyaniline (PANI)-functionalized Ni-doped ordered mesoporous carbon (OMC) by in situ polymerization method. The polymer-functionalized nanocomposites, embedding polyaniline within ordered mesoporous carbon, exhibit strong and broadband microwave absorption due to its better dielectric loss characteristic. OMC-Ni0.15/PANI exhibits an effective absorption bandwidth (i.e., reflection loss (RL) ≤ −10 dB) of 4.7 GHz and an absorption peak of −51 dB at 9.0 GHz. The absorption peak intensity and position can be tuned by controlling the thickness of the coating. 相似文献
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在高速搅拌条件下调整分子组装过程的外界应力,制备出短通道(500~700 nm)、条棒状的有序介孔二氧化硅,研究不同模板剂脱除方式对介孔二氧化硅的水蒸气吸附性能影响,获得强化介孔二氧化硅吸附性能的方法。结果表明:在短通道、条棒状介孔二氧化硅的制备过程中模板剂脱除的温度对材料表面羟基浓度影响较大,选择萃取与低温煅烧相结合方法脱除模板剂,萃取4次,250℃煅烧脱除模板剂的材料水蒸气吸附性能最好,在实验条件下平衡吸附时间约为7.5 min,是商品SBA-15的78.95%;平衡吸附量0.73 g·g^(-1),是商品SBA-15的1.49倍。 相似文献
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Sandwich-type ordered mesoporous carbon/graphene nanocomposites were successfully synthesized using 2D ordered mesoporous silica/graphene nanocomposites as the hard template and an ionic liquid as a N-rich carbon source. We used an ionic liquid of 1-(3-cyanopropyl)-3-methylimidazolium dicyanamide containing nitrile groups (–CN) in the cation and anion as a carbon precursor for the preparation of the nanocomposites. Nitriles do not decompose under thermal treatment in an inert gas atmosphere, but leave significant amounts of N-rich carbon materials. The nanocomposites had a large surface area (1,316 m2·g–1), an average pore diameter of 5.9 nm, and high electrical conductivity. The nanocomposite electrode showed a high specific capacitance of 190 F·g–1 at 0.5 A·g–1 in 1 M TEABF4/AN electrolyte and a good rate capability between 0 and 2.7 V for supercapacitor (or ultracapacitor) applications. 相似文献
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AbstractIn this study, we proposed to modify mesoporous silica nanoparticles (MSNs) with 3-aminopropyltriethoxysilane (NH2-TES), aminoethylaminopropyltriethoxysilane (2NH2-TES) and 3-[2-(2-aminoethylamino)ethylamino] propyl-trimethoxysilane (3NH2-TES) for binding of cytosine-phosphate-guanosine oligodexynucleotides (CpG ODN), and investigated the effect of different amino groups of MSNs on the CpG ODN delivery. Serum stability, in vitro cytotoxicity, and cytokine interleukin-6 (IL-6) induction by MSN-NH2/CpG, MSN-2NH2/CpG and MSN-3NH2/CpG complexes were investigated in detail. The results showed that three kinds of aminated-MSN-based CpG ODN delivery systems had no cytotoxicity to RAW264.7 cells, and binding of CpG ODN to MSN-NH2, MSN-2NH2 and MSN-3NH2 nanoparticles enhanced the serum stability of CpG ODN due to protection by the nanoparticles. However, three aminated MSN-based CpG ODN delivery systems exhibited different CpG ODN delivery efficiency, and MSN-NH2/CpG complexes had the highest ability to induce IL-6 secretion. 相似文献
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