共查询到20条相似文献,搜索用时 46 毫秒
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采用均相沉淀法制备了氧化锌(ZnO)前驱体,通过煅烧前驱体制备了不同粒径的ZnO纳米颗粒,并在此基础上制备了ZnO/环氧纳米复合材料.借助TG、XRD和TEM等手段对纳米ZnO进行了表征,采用UV-VIS研究了ZnO含量、颗粒粒径等因素对复合材料光学性能的影响.研究结果表明:在紫外光区,提高ZnO的含量和选择ZnO最佳粒径,可以改善对紫外光的屏蔽效果;随着ZnO粒径的减小,ZnO对紫外光的屏蔽存在明显的蓝移现象,因此选择合适的粒径尤为重要.在可见光区,ZnO含量和颗粒粒径的影响相似,当ZnO含量低于0.07wt%、粒径小于27nm时复合材料的透过率几乎没有变化,增加含量或增大粒径透过率则随之下降.当ZnO的粒径为27nm时,添加0.07wt%的ZnO所制备的ZnO/环氧纳米复合材料具有优异的光学性能:在保持可见光区高透明性的同时又能够对紫外光区有良好的屏蔽效果,能够满足LED封装等光学器件的需要. 相似文献
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Due to their outstanding mechanical, thermal, and durability properties, polymer matrix nanocomposites (PMCs) are currently a prominent area of research. The opportunity of applying PMCs in structural reinforcement and rehabilitation of damaged infrastructures, as well as working as a new structural material, justifies the increasing number of recent studies. In this review article, the effect of adding different reinforcements at nano-scale, such as carbon nanotubes, nanoclay, graphene, or nanosilica to polymer matrices, is discussed and the improvement in mechanical properties of PMCs is evaluated. Some concluding remarks and new perspectives on the use of PMCs in structures are given. 相似文献
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Graphene oxide (GO) was added to a polymer composites system consisting of surfactant-wrapped/doped polyaniline (PANI) and divinylbenzene (DVB). The nanocomposites were fabricated by a simple blending, ultrasonic dispersion and curing process. The new composites show higher conductivity (0.02–9.8 S/cm) than the other reported polymer system filled with PANI (10−9–10−1 S/cm). With only 0.45 wt% loading of GO, at least 29% enhancement in electric conductivity and 29.8% increase in bending modulus of the composites were gained. Besides, thermal stability of the composites was also improved. UV–Vis spectroscopy, X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) revealed that addition of GO improves the dispersion of PANI in the polymer composite, which is the key to realize high conductivity. 相似文献
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Magnetic nanocomposites with well-defined mesoporous structures, shapes, and tailored properties are of immense scientific and technological interest. This review article is devoted to the progress in the synthesis and applications of magnetic mesoporous materials. The first part briefly reviews various general methods developed for producing magnetic nanoparticles (NPs). The second presents and categorizes the synthesis of magnetic nanocomposites with mesoporous structures. These nanocomposites are broadly categorized into four types: monodisperse magnetic nanocrystals embedded in mesoporous nanospheres, microspheres encapsulating magnetic cores into perpendicularly aligned mesoporous shells, ordered mesoporous materials loaded with magnetic NPs inside the porous channels or cages, and rattle-type magnetic nanocomposites. The third section reviews the potential applications of the magnetic nanocomposites with mesoporous structures in the areas of heath care, catalysis, and environmental separation. The final section offers a summary and future perspectives on the state-of-the art in this area. 相似文献
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Yutaka Oya Kyosuke Inuyama Tomonaga Okabe Jun Koyanagi Ryosuke Matsuzaki 《Advanced Composite Materials》2018,27(4):427-438
The characteristics of laminated graphene oxide (LGO) nanocomposite, which are expected to be used for highly functional composites, are known to be related to its microstructure. In this study, we investigate the influences of hydrogen-bonding and cross-linked network structures on the initial stiffness and yield stress, using molecular dynamics simulations. Our results show that each structure increases the mechanical properties, and the combination of these structures strengthens the properties. Moreover, we found that the physical origin of the enhancement is cross-linked networks that generate stretched polymers connecting graphene sheets. Our study concludes by suggesting an appropriate selection of materials for high-performance LGO nanocomposites. 相似文献
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Shantala D. Patil S. C. Raghavendra M. Revansiddappa P. Narsimha M. V. N. Ambika Prasad 《Bulletin of Materials Science》2007,30(2):89-92
Conducting polyaniline/cobaltous oxide composites have been synthesized using in situ deposition technique by placing fine graded/cobaltous oxide in polymerization mixture of aniline. The a.c. conductivity and
dielectric properties are studied by sandwiching the pellets of these composites between the silver electrodes. It is observed
that the values of conductivities increase up to 30 wt% of cobaltous oxide in polyaniline and decrease thereafter. Initial
increment in conductivity is due to extended chain length of polyaniline where polarons possess sufficient energy to hop between
favourable sites. Beyond 30 wt% of cobaltous oxide in polyaniline, blocking of charge carriers takes place reducing the conductivity
values. It can be noted that the value of dielectric constant increases up to 10 wt% of cobaltous oxide. Thereafter, it decreases
up to 30 wt% of cobaltous oxide and again increases up to 40 wt% of cobaltous oxide and decreases thereafter. The observed
behaviour is attributed to the variation of a.c. conductivity. And it is observed that the dielectric loss increases up to
10 wt% of cobaltous oxide in polyaniline, decreases to a lower value of 20 wt% of cobaltous oxide and increases to 35 wt%
and thereafter decreases. These values go in accordance with the values of dielectric constant. The results obtained for these
composites are of greater scientific and technological importance. 相似文献
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Optical and structural properties of porous zinc oxide fabricated via electrochemical etching method
C.G. Ching S.C. Lee P.K. Ooi S.S. Ng Z. Hassan H. Abu Hassan M.J. Abdullah 《Materials Science and Engineering: B》2013,178(15):956-959
We investigated the optical and structural properties of porous zinc oxide (ZnO) thin film fabricated by ultraviolet light-assisted electrochemical etching. This fabrication process used 10 wt% potassium hydroxide solution as an electrolyte. Hillock-like porous ZnO films were successfully fabricated according to the field emission scanning electron microscopy results. The cross-sectional study of the sample indicated that anisotropic-dominated etching process occurred. However, the atomic force microscopic results showed an increase in surface roughness of the sample after electrochemical etching. A resonance hump induced by the porous structure was observed in the infrared reflectance spectrum. Using theoretical modeling technique, ZnO porosification was verified, and the porosity of the sample was determined. 相似文献
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采用超声辅助Hummers法制得厚度约为1 nm的氧化石墨烯, 以其为氧化介质与苯胺反应合成了石墨烯/聚苯胺(RGO/PANI)导电复合材料。利用AFM、SEM、XRD和FTIR对反应所得产物进行了表征。结果表明: 苯胺在略高于室温的酸性水溶液中可以对氧化石墨烯(GO)进行还原, 而苯胺自身则被氧化石墨烯中大量的含氧基团氧化并发生聚合反应, 最终生成RGO/PANI导电复合材料, 当苯胺用量为1 mL, 氧化石墨烯用量为0.1 g, 在水浴温度为70 ℃下剧烈搅拌24 h时, 获得的RGO/PANI复合材料导电性最佳, 约为10 S/cm。 相似文献
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Damien Hudry Jean-Christophe Griveau Christos Apostolidis Olaf Walter Eric Colineau Gert Rasmussen Di Wang Venkata Sai Kiran Chakravadhaluna Eglantine Courtois Christian Kübel Daniel Meyer 《Nano Research》2014,7(1):119-131
One of the primary aims of the actinide community within nanoscience is to develop a good understanding similar to what is currently the case for stable elements. As a consequence, efficient, reliable and versatile synthesis techniques dedicated to the formation of new actinide-based nano-objects (e.g., nanocrystals) are necessary. Hence, a "library" dedicated to the preparation of various actinidebased nanoscale building blocks is currently being developed. Nanoscale building blocks with tunable sizes, shapes and compositions are of prime importance. So far, the non-aqueous synthesis method in highly coordinating organic media is the only approach which has demonstrated the capability to provide size and shape control of actinide-based nanocrystals (both for thorium and uranium, and recently extended to neptunium and plutonium). In this paper, we demonstrate that the non-aqueous approach is also well adapted to control the chemical composition of the nanocrystals obtained when mixing two different actinides. Indeed, the controlled hot co-injection of thorium acetylacetonate and uranyl acetate (together with additional capping agents) into benzyl ether can be used to synthesize thorium/uranium mixed oxide nanocrystals covering the full compositional spectrum. Additionally, we found that both size and shape are modified as a function of the thorium:uranium ratio. Finally, the magnetic properties of the different thorium/uranium mixed oxide nanocrystals were investigated. Contrary to several reports, we did not observe any ferromagnetic behavior. As a consequence, ferromagnetism cannot be described as a universal feature of nanocrystals of non-magnetic oxides as recently claimed in the literature. 相似文献
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采用原位聚合法,以过硫酸铵为氧化剂,在比表面积为2945cm2/g的中间相沥青基活性炭微球(AMCMB)表面引发苯胺聚合,制备中间相沥青基活性炭微球/聚苯胺复合材料(AMCMB/PANI)。利用扫描电镜、X射线衍射和傅里叶变换-红外光谱分析,考察其微观结构和表面形貌;通过恒流充放电、循环伏安及交流阻抗测试,研究其在6mol/L KOH溶液中的电化学性能。在电流密度为0.02A/g时,AMCMB/PANI电极的比容量为387.72F/g,与AMCMB电极的比容量相比,提高了57.46%,说明少量聚苯胺的加入可以显著地提高电极材料的比容量;当电流密度增大1000倍时,AMCMB/PANI电极的比容量为157.68F/g,表现出好的大电流充放电能力。 相似文献
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用机械化学及热压烧结方法成功制备了高致密Ni-20Fe/ Al2O3 纳米复合材料。通过X2ray、FE-SEM、力学性能、磁性能测试, 结果表明, 复合后材料断裂韧性从纯α2Al2O3 相的4. 7 MPa·m1/2 提高到6. 2 MPa·m1/2(19 % (Ni-20Fe) / Al2O3 ) , 断裂方式有沿晶断裂和穿晶断裂两种。当Ni-20Fe 合金的体积百分数达到19 %时, 复合材料的饱和磁化强度达33 emu/ g , 矫顽力为200 Oe , 且在低于500 ℃的情况下, 矫顽力基本不随温度而变, 具有良好的磁热稳定性。 相似文献
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H. Q. Wu D. M. Xu Q. Wang Y. Z. Yao Q. Y. Wang G. Q. Su 《Bulletin of Materials Science》2008,31(5):801-806
Fe46Co35Ni19/CNTs nanocomposites have been prepared by an easy two-step route including adsorption and heat treatment processes. We investigated
the effect of heat treatment conditions on structure, morphology, nanoparticle sizes and magnetic properties of the Fe46Co35Ni19 alloy nanoparticles attached on the carbon nanotubes by X-ray powder diffraction (XRD), scanning electron microscopy (SEM),
high-resolution transmission electron microscopy (HRTEM), energy-disperse X-ray spectroscopy (EDS) and vibrating sample magnetometer
(VSM). When the reducing temperature changes from 300–450°C, a transition of the crystalline structure from bcc phase to fcc-bcc dual phase and an increase in particle size of Fe46Co35Ni19 nanoparticles together with a local maximum at 350°C are observed. Meanwhile, the saturation magnetization (M
s) for Fe46Co35Ni19 nanoparticles increases with the increase of reducing temperature and the coercivity (H
c) decreases rapidly with a local minimum at 350°C. When the reducing time (tr) changes from 2–5 h, bcc phase is predominant in the Fe46Co35Ni19 alloy particles. Both the particle size and M
s have a maximum at tr = 3 h, and the H
c reaches a maximum at tr = 4 h. 相似文献
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采用超声场下原位聚合法制备了Ba0.6Sr0.4-TiO3/PANI复合材料。其结构、形貌和电磁性能分别采用X射线衍射仪(XRD)、扫描电镜(SEM)和HP8510网络矢量分析仪进行了研究。结果表明,HCl掺杂后的PANI是部分结晶的。Ba0.6Sr0.4TiO3与PANI分子链之间存在某些相互作用。与PANI相比,在8.2~12GHz频率范围内,Ba0.6Sr0.4TiO3/PA-NI复合物的ε′值和ε″值均较大。在9.8~12.4GHz的频率范围内,Ba0.6Sr0.4TiO3/PANI复合物的tanδε值大于PANI的tanδε值。Ba0.6Sr0.4TiO3/PANI复合材料具有较好的微波吸收性能,最大损耗为-14dB,-10dB带宽超过了5GHz。 相似文献
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Conducting nanocomposites of polyacrylonitrile (PAN) and antimony-doped tin oxide (ATO) were prepared by solution blending.
Electrical properties of the nanocomposites were characterized by means of electrical conductivity measurements and the phase
structures were investigated via scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analyses (TGA)
and dynamical mechanical analysis (DMA). This study unveiled a remarkable, interpenetrating network of chainlike nano-ATO
within the PAN matrix, consistent with the existence of connected conducting paths at content as low as 4 wt% of the nano-ATO.
The storage modulus of the nanocomposites increased with increasing content of ATO, due to formation of immobilized layer
between polymer and filler. The interactions between ATO and PAN molecules resulted in high tan δ for the PAN/ATO nanocomposites. Thermal stability of the nanocomposites was found remarkably enhanced by the incorporation
of nano-ATO. 相似文献