共查询到19条相似文献,搜索用时 62 毫秒
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利用高压均质液相剥离法,以鳞片石墨为原料,水为介质,制备高浓度石墨烯水分散液。采用紫外可见光谱研究表明活性剂浓度、高压均质压力和循环次数对石墨烯水分散液浓度C_G的影响。通过拉曼光谱、扫描电镜、透射电镜、激光粒度仪分析水分散液中石墨烯的结构和形貌。结果表明:通过调节各工艺参数,获得了浓度为324.3mg·L-1的石墨烯水分散液,所得浓度是超声液相剥离法的10倍;石墨烯水分散液中石墨烯缺陷少、厚度薄、片径大,具有良好的品质;将所得石墨烯分散液制备石墨烯自支撑膜,其电导率可达3.2×10~4S·m-1。 相似文献
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为了提高热还原法制备的还原氧化石墨烯(RGO)在水溶液中的分散性,采用超声波处理结合非离子表面活性剂分散的方法,选择聚乙烯吡咯烷酮(PVP)、吐温80(TW-80)和聚乙烯醇(PVA)三种非离子表面活性剂,研究RGO的分散性能。通过静置法分析了不同非离子表面活性剂对RGO水溶液的分散稳定性,结果表明添加非离子表面活性剂能有效提高RGO的分散性,其中1.5%PVP K30和3%TW-80处理后的RGO分散稳定性最好。通过拉曼光谱、X射线衍射(XRD)、扫描电镜(SEM)和透射电镜(TEM)等对分散后的RGO进行了表征,结果表明,分散后RGO的层间距增大,PVP K30-RGO的表面褶皱较少,较为光滑,且层间距最大,为0.42nm。 相似文献
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选用非离子表面活性剂(TX-100)作为分散剂,制备了稳定性较好的石墨-H2O分散液.通过测定石墨-H2O分散液的吸光度和Zeta电位,探讨了不同TX-100添加量、pH值、电解质对石墨-H2O分散液稳定性的影响,并分析了作用机理.结果表明,TX-100的添加量存在一个最佳值,以石墨质量为基准,TX-100用量为25%时,分散液稳定性最好;分散液受pH值影响较小,在较宽的pH值范围内都能达到稳定,在pH=3的强酸性环境下,由于电荷中和及分散剂吸附状态的变化导致分散液稳定性下降;电解质的加入严重破坏了体系稳定性;该体系中,主要通过空间斥力使石墨粒子稳定,同时静电斥力也是不可忽略的因素;石墨-H2O分散液的粒径分布及粘度曲线表明,石墨粒子在水中达到良好的分散. 相似文献
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通过氧化还原法合成石墨烯,结合1-萘甲酸的双极性作用防止石墨烯发生自团聚,得到稳定的胶体分散液。通过分析拉曼光谱的特征峰确定了氧化石墨烯的还原程度;利用TEM观察到了单层、双层以及多层的石墨烯。通过测试分散液的zeta电位、粒径以及丁达尔效应,参照胶体的经典稳定理论—DLVO理论,阐述了石墨烯分散液稳定存在的原因和机理,并进一步通过蒸发溶胶合成了自组装无基底的石墨烯薄膜。各项结果表明,利用该法合成的石墨烯分散液具有大量稳定存在的单层石墨烯,是当前石墨烯基微纳器件所需的优良前驱体。为液相化学法制备石墨烯提供了理论支撑,为石墨烯的后续应用开辟了新的途径。 相似文献
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表面活性剂对液膜分离传质性能的影响 总被引:3,自引:0,他引:3
研究了不同表面活性剂组成的液膜体系在分离过程中的传质、溶胀和渗透等性能,分别考查了聚胺型表面活性剂L-113A和LMA-1及酯型表面活性剂Span80对含P204载体液膜体系迁移镧(Ⅲ)的影响,以及L—113A、L—113B和EM-301对无载体液膜体系富集氨氮的影响.实验表明,因表面活性剂不同,造成乳状液膜体系在分离富集镧或氨氮时,分离传质性能相差较大,LMA—1—P204-煤油的液膜体系对镧具有最大的迁移能力。迁移率97.4%;而L-113A-膜相添加剂-煤油的液膜体系对氨氮的溶解渗透能力最大。迁移率为86.4%.另外,对因表面活性剂结构不同而造成油水界面黏度的差异以及对传质速率的影响,从乳状液膜和自组装双分子液膜等方面进行了探讨. 相似文献
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液膜用高分子表面活性剂性能研究 总被引:7,自引:2,他引:5
本文介绍液膜用高分子表面活性剂PSN_(-89414)的性能,通过界面张力测定,用表面活性剂分子在界面上吸附理论导出公式求得Span80,PSN_(-89414)的界面吸附平衡常数K_(s)及S_(sf)的数值,结果表明,K_(s)、S_(sf)数值愈大的表面活性剂制得乳状液愈稳定,液膜溶胀愈小。PSN_(-89414)的W/O/W乳状液体系用于稀土分离,速度快,从浓度1.2g/L的稀土溶液浓集到103g/L。 相似文献
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Zeeshan Baig Othman Mamat Mazli Mustapha Mansoor Sarfraz 《Fullerenes, Nanotubes and Carbon Nanostructures》2017,25(9):545-557
Graphene dispersion in aluminium matrix is a critical concern for the attainment of composite improved mechanical and tribological properties which hinders broad applications of Al nanocomposites. Herein, graphene nanoplatelets (GNPs) dispersion in Al matrix achieved by colloidal processing, i.e., combining sonication and surfactant dispersing aid. In this work, the performance of the two types of surfactant (anionic, sodium dodecyl benzene sulfonate (SDBS), and nonionic polymeric, ethyl cellulose (EC)) were evaluated for effective GNPs dispersion in a solvent and Al matrix. Surfactant assisted GNPs solvent dispersion characterized through sedimentation test and UV-vis spectroscopy to optimize surfactant concentration. Density, hardness, wear properties and microstructural characterizations of GNPs/Al powder and sintered discs were performed to gauge the effect of surfactant type. It was found that surfactant addition enhances dispersion ability of GNPs than neat GNPs but at low GNPs fractions. The results show that EC assisted GNPs/Al nanocomposites of 0.5 wt% GNPs concentration has shown an increase in hardness (31%) and reduce wear rate (98%). Whereas, 0.3 wt% SDBS assisted GNPs/Al nanocomposites shown maximal increases in hardness (18%) and reduce wear rate (98%) as compared to pure aluminium, respectively. Conclusively, it has been revealed that polymeric EC based surfactant GNPs owing to steric repulsion shows better dispersion effect resulting in high density and improved wear resistance and performed better than SDBS based surfactant GNPs in Al matrix. 相似文献
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In order to measure aqueous solution concentration, radio frequency resonator sensors based on sections of a long line are
proposed: two-conductor, coaxial and screened with a U-shaped inner conductor. Specific sensor structural features and the
contents of their radio frequency measuring devices are described. Results are provided for experimental confirmation of the
efficiency of these sensors for measuring the concentration of various two-component liquids with losses.
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Translated from Izmeritel’naya Tekhnika, No. 10, pp. 65–67, October 2007. 相似文献
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Kate Ryan Sabine M. Neumayer Harsha Vardhan R. Maraka Nicolae-Viorel Buchete Andrei L. Kholkin James H. Rice 《Science and Technology of Advanced Materials》2013,14(1):172-179
AbstractNanocomposites of diphenylalanine (FF) and carbon based materials provide an opportunity to overcome drawbacks associated with using FF micro- and nanostructures in nanobiotechnology applications, in particular their poor structural stability in liquid solutions. In this study, FF/graphene oxide (GO) composites were found to self-assemble into layered micro- and nanostructures, which exhibited improved thermal and aqueous stability. Dependent on the FF/GO ratio, the solubility of these structures was reduced to 35.65% after 30 min as compared to 92.4% for pure FF samples. Such functional nanocomposites may extend the use of FF structures to e.g. biosensing, electrochemical, electromechanical or electronic applications. 相似文献
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In this study, one-dimensional vision of carrier movement based on the band structure of trilayer graphene nanoribbon in the presence of a perpendicular electric field is employed. An analytical model of ABA-stacked trilayer graphene nanoribbon carrier statistics as a fundamental parameter of field effect transistor (FET) in corporation with a numerical solution is presented in the degenerate and non-degenerate limits. The simulated results based on the presented model indicate that the model can be approximated by degenerate and non-degenerate approximations in some numbers of normalised Fermi energy. Analytical model specifies that carrier concentration in degenerate limit is strongly independent of normalised Fermi energy; however, in the non-degenerate limit, it is a strong function of normalised Fermi energy. The proposed model is then compared with other types of graphene. As a result, the developed model can assist in comprehending experiments involving trilayer graphene nanoribbon FET-based devices. 相似文献
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纳米Al2O3粒子浓度对弥散强化铜合金退火行为的影响 总被引:1,自引:0,他引:1
通过力学性能、金相和TEM观察对低、中浓度Cu-Al2O3弥散强化铜合金的退火行为进行了研究.结果表明:低浓度弥散强化铜合金具有一定的抗高温软化性能,500℃退火后发生再结晶,900℃退火后已基本完全再结晶,屈强比约为56%.中浓度合金抗高温软化性能较好,900℃退火后,合金仍然以回复过程为主,金相尺度下不能看到再结晶晶粒,屈强比可达70%.弥散强化铜合金优越的抗高温软化性能归功于铜基体内均匀弥散分布的纳米Al2O3粒子.Al2O3粒子尺寸在10~20nm内时,粒子间距>200nm时,阻碍晶界迁移能力较差,粒子间距<90nm时,可显著阻碍晶界的迁移,合金抗高温软化性能优越. 相似文献
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通过对新型耐高温聚合物杂萘联苯聚芳醚腈酮(PPENK)中的氰基转化为亲水性基团羧基或酰胺基,系统地研究了改性聚芳醚腈酮(HPPENK)在耐高温水性涂料中的应用,考察了不同氰基转化率的HPPENKa(55.82%)、HPPENKb(78.23%)和HPPENKc(93.82%)树脂作为主要成膜物质的水分散体的性能,其中HPPENKc具有较好的分散稳定性和良好的成膜性,漆膜附着力(划圈法)为一级,铅笔硬度>6H,能耐受300℃(24h),对水和有机溶剂有一定耐受能力.甄选了六甲基醚化三聚氰胺树脂(HMMM)、环氧氯丙烷(ECH)、三乙醇胺、甘油、乙二胺等作为HPPENK的交联剂,其中HMMM和环氧氯丙烷具有较好的交联效果,外加乳化剂采用司班和吐温的复配取得较好的乳化效果.同时,通过考察了乳化剂、分散剂、中和剂、附着力促进剂等涂料助剂的选择及用量,提出了水分散体配方. 相似文献