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Pastes for field emission test were prepared by 3-roll milling of multi-walled carbon nanotubes (MWNTs) and UV-sensitive binder solution. The effects of four filler additives, namely two types of indium tin oxide (ITO) powder, glass frit and Ag on the field emission properties of the screen-printed paste were investigated and compared to those without filler using a diode-type configuration. The paste formulation was shown to be adequate for fine patterning using a UV-lithography technique. MWNT pastes containing any type of filler showed better emission properties than the paste without filler, thereby confirming the importance of the filler. The MWNT paste with 1 wt.% glass frit showed the best results with the lowest turn-on field of 1.75 V/μm at 1 μA/cm2, highest emission current density of 78 μA/cm2 at 5 V/μm, and β-factor of 17,000 approximately, which are satisfactory for practical application. 相似文献
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Ruili Wang Shuang Bao Fengwei Liu Xiaoze Jiang Qinghong Zhang Bin Sun Meifang Zhu 《Materials science & engineering. C, Materials for biological applications》2013,33(8):4759-4766
To enhance wear behavior of resin composites, bimodal silica nanostructures including silica nanoparticles and silica nanoclusters were prepared and proposed as fillers. The silica nanoclusters, a combination of individually dispersed silica nanoparticles and their agglomerations, with size distribution of 0.07–2.70 μm, were fabricated by the coupling reaction between amino and epoxy functionalized silica nanoparticles, which were obtained by the surface modification of silica nanoparticles (~ 70 nm) using 3-aminopropyl triethoxysilane (APTES) and 3-glycidoxypropyl trimethoxysilane (GPS) as coupling agents, respectively. Silica nanoparticles and nanoclusters were then silanized with 3-methacryloxypropyl trimethoxysilane (γ-MPS) to prepare composites by mixing with bisphenol A glycerolate dimethacrylate (Bis-GMA) and tri (ethylene glycol) dimethacrylate (TEGDMA). Experimental composites with various filler compositions were prepared and their wear behaviors were assessed in this work. The results suggested that composites with increasing addition of silica nanoparticles in co-fillers possessed lower wear volume and smoother worn surface. Particularly, the composite 53:17 with the optimum weight ratio of silica nanoparticles and silica nanoclusters presented the excellent wear behavior with respect to that of the commercial Esthet-X, although the smallest wear volume was achieved by Z350 XT. The introduction of bimodal silica nanostructures as fillers might provide a new sight for the design of resin composites with significantly improved wear resistance. 相似文献
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《Materials Letters》2007,61(11-12):2156-2158
Epoxy resin coated silica fillers composites with high percentage of filler loading, such as 80 to 95 vol.% are able to be produced by a mechanical mixing technique. The advantages of high filler loading of theses materials are noted from the thermal and flexural modulus. Apparently, the materials exhibit low coefficient of thermal expansion (CTE) at as low as or below 10 ppm/°C and high flexural modulus of above 20 GPa. In general, these promising characteristics fulfill the requirement to be used as substrate materials in electronic packaging applications. 相似文献
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将原位乳液聚合制得的SiO2-聚合物杂化微球与聚丙烯熔融共混制备了SiO2/聚丙烯(SiO2/PP)复合材料, 利用差示扫描量热法(DSC)研究了SiO2/PP复合材料的非等温结晶动力学行为。结果表明, SiO2-聚合物杂化微球具有明显的异相成核效应, 提高了PP的结晶温度和结晶速率, 同时降低了PP的结晶度, 提高了PP的结晶活化能。运用Mo法处理纯PP和SiO2/PP复合材料的非等温结晶动力学, 结果显示SiO2-聚合物杂化粒子降低了聚丙烯在单位结晶时间内达到一定结晶度时所需的降温速率。 相似文献
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Rubber compounds are traditionally reinforced with carbon black or silica fillers of minute particle size. Prior studies in which much larger recycled rubber scrap has been incorporated, indicate that only low levels can be tolerated before significant deterioration in performance is noted. Failure can be superficially linked to macroscopic flaws as is commonly observed in both thermoplastics and elastomers. In this study a detailed examination of soft elastomeric fillers in a polybutadiene matrix is described. In particular the effect of filler hardness and interfacial bonding is stressed. An estimation of the interfacial adhesion is made from peel tests. 相似文献
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将原位乳液聚合制得的SiO2-聚合物杂化微球与聚丙烯熔融共混制备了SiO2/聚丙烯(SiO2/PP)复合材料,利用差示扫描量热法(DSC)研究了SiO2/PP复合材料的非等温结晶动力学行为.结果表明,SiO2-聚合物杂化微球具有明显的异相成核效应,提高了PP的结晶温度和结晶速率,同时降低了PP的结晶度,提高了PP的结晶活化能.运用Mo法处理纯PP和SiO2/PP复合材料的非等温结晶动力学,结果显示SiO2-聚合物杂化粒子降低了聚丙烯在单位结晶时间内达到一定结晶度时所需的降温速率. 相似文献
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聚合物材料因其质轻、价廉、耐腐蚀以及优异的自润滑特性而广泛应用于工程机械润滑领域中。加入功能性减摩和增强填料复合改性聚合物树脂可以克服本征型高分子材料的一些固有缺陷,得到低摩擦因数、高耐磨性、高承载力以及耐高温等优异特性的摩擦学复合材料。本文综述了功能性填料如碳基材料、过渡金属硫化物、微胶囊、软金属、陶瓷纳米颗粒、矿物盐以及自润滑高分子对复合材料的减摩抗磨效果及机理。同时,力学性能是保证聚合物材料服役性能和使役寿命的关键参数,也会对材料的摩擦学性能带来显著影响。本文还重点论述了纳米颗粒和纤维等填料对复合材料的增强和增韧机理。最后,展望了功能性填料对力学性能与摩擦学性能的协效作用,以及计算机模拟在复合材料摩擦学中应用的发展趋势。 相似文献
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A detailed examination of failure of properties of polybutadiene containing soft elastomeric fillers has previously been described [1]. Here the effect of filler modulus and filler-matrix adhesion on tear strength is measured. Tear behaviour depends upon the level of interfacial adhesion; when high, tear strength increases with increasing filler hardness, but if interfacial adhesion is low, incorporation of fillers may result in low tear strengths. An estimate of the edge flaw size is made from the tear strength and strain energy densities at break. It was found that compounds with low interfacial adhesion generally had edge flaw sizes of the same order as the maximum filler particle size. A correlation between tear strength and tear surface morphology is made. 相似文献
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Anna Wolska Marcin Go?dzikiewicz Joanna Ryszkowska 《Journal of Materials Science》2012,47(15):5627-5634
Flexible polyurethane foams (FPF) are polymer materials that have high flammability. Fyrol PNX (FPNX) and expandable graphite (EG), have been used to modify the properties of these materials. The aim of this study was to assess the possibility of improving the thermal stability and flame retardancy of FPF by the addition of FPNX and EG fillers. The prepared foams were characterised by their apparent density, hardness, flexibility, irreversible strain and linear flammability, as well as thermogravimetric analysis (TGA), dynamic mechanical analysis, Fourier transform infrared spectroscopy (FT-IR) and pyrolysis combustion flow calorimetry (PCFC) measurements. The apparent density, hardness, flexibility and irreversible strain results showed that the addition of graphite and phosphorous fillers to the FPF makes slight changes to the mechanical properties, which remain within the acceptable norms. It was also observed that reducing the amount of Fyrol PNX and replacing it with the same amount of EG allowed similar values of linear flammability to be obtained with a simultaneous increase in thermal stability, as shown in the TGA study and the PCFC test. Moreover, it was found that the modification of flexible polyurethane foam by the addition of a mixture of FPNX and EG fillers allows the best properties of this type of materials to be obtained. This result indicates that this type of modification could be an effective way to improve the thermal stability of FPF. 相似文献
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Short fibre reinforced polymer composites are nowadays used in numerous tribological applications. In spite of this fact, new developments are still under way to explore other fields of application for these materials and to tailor their properties for more extreme loading conditions. The references given at the end of this review describe some of these developments. In the present overview further approaches in designing polymeric composites in order to operate under low friction and low wear against steel counterparts are described. A particular emphasis is focused on special filler (including nanoparticle) reinforced thermoplastics and thermosets. Especially, the influence of particle size and filler contents on the wear performance is summarised. In some of the cases, an integration of traditional fillers with inorganic nanoparticles is introduced and presents an optimal effect. Furthermore, some new steps towards the development of functionally graded tribo-materials are illustrated. 相似文献
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Preparation of high silica microporous zeolite SSZ-13 using solid waste silica fume as silica source
Yuanhui Wang Jieyu Chen Xinrong Lei Yuujie Ren Ji Wu 《Advanced Powder Technology》2018,29(5):1112-1118
Silica fume (SF) is a kind of solid waste that produced in the process of industrial silicon smelting. The disposal of SF for environmental problem is of great urgency. Here, a facile and novel one-step approach of high silica microporous materials SSZ-13 (SF-SSZ-13) were hydrothermally synthesized using silica fume (SF) as silica source. This method requires significantly shorter reaction times (48?h) compared to conventional SSZ-13. The as-synthesized SF-SSZ-13 exhibited high purity structure, popcorn-like morphology, and a large BET surface area of 545.74?m2?g?1. Additionally, on the basis of controlled growth under different hydrothermal times, the formation mechanism of the SF-SSZ-13 outlined for further extension to other materials. The results on time- and energy-efficient of SF-based preparation of SSZ-13 pave the way for the reducing the cost of production of raw materials and decreasing environment load of solid waste, and also extend the application of silica fume. 相似文献
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Emilie Planes Laurent Chazeau Gérard Vigier Thomas Stuhldreier 《Composites Science and Technology》2010
This study evidences that the presence of silica fillers as well as their surface treatment influences the impact of gamma irradiation on the mechanical properties of the filled materials. It influences it both chemically, by a modification of the kinetics of the degradation reactions, and physically, through the complex modification of the filler–filler and filler–matrix interactions involved in the mechanical properties of the filler network. 相似文献
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Diego A. Acosta Gary P. Funkhouser Brain P. Grady 《Journal of Materials Science》2007,42(10):3632-3644
Low-cost polyalkenoate cements analogous to dental cements, i.e., cements based on polymers of acrylic acid crosslinked via
bridging metal cations, were developed with a goal of producing a more flexible alternative to Portland cement. Economic constraints
necessitated the replacement of the acid-degradable glass normally used in dental cements; the purpose of the glass is to
provide both a source of polyvalent cations for crosslinking and solid filler for a composite material. The dual functionality
of the powdered glass was accomplished via the use of manganese tetraoxide as the filler and aluminum chloride as the cation
source for the ionic crosslinks. Unlike dental cements that have a gel-like consistency before setting, low viscosity cements
were produced by using acrylic acid monomer rather than low-molecular weight poly(acrylic acid). Mechanical and rheological
properties were used to monitor cement characteristics. Because of the large number of formulation variables, a design of
experiments (DOE) approach was used. DOE helped narrow the search for formulations that would result in hardened cements and
find the optimal set of ingredients that led to cements with the best properties given the economic constraints on the ingredients.
Rheology was adjusted to match that of Portland cement by altering the filler volume fraction, which was very effective since
the rheology depended strongly on that variable. The most pertinent independent variables for the mechanical properties were
the curing time and monomer/cation ratio in the ranges tested; however, the monomer/water ratio was fixed at the minimum level
possible and not increased because of economic considerations. The best materials produced in terms of mechanical properties
resulted when acrylic acid monomer was partially replaced by N,N′-methylenebisacrylamide; this substitution resulted in a stronger and tougher cement.
An erratum to this article can be found at 相似文献
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Effect of fillers on natural rubber/high styrene rubber blends with nano silica: Morphology and wear 总被引:1,自引:0,他引:1
Kaushik Pal R. Rajasekar Dong Jin Kang Zhen Xiu Zhang Samir K. Pal Chapal K. Das Jin Kuk Kim 《Materials & Design》2010,31(2):677-686
The blends of high styrene rubber (HSR) and natural rubber (NR) with nano silica were prepared using a blending technique in presence of different types of carbon black. The effect of filler on morphological and wear characteristics was studied. ISAF (Intermediate Super Abrasion Furnace) type of carbon black have showed a significant effect on optimum cure time, cure rate index and mechanical properties by reacting at the interface between HSR and NR matrix. All the samples show only one melting peak on the DSC curve; this is attributed to the same backbone structure of the matrix and the carbon black reinforcement. The samples containing 30 wt.% of HSR with ISAF type of carbon black has shown maximum heat buildup, lower swelling and lower compression set value. Blends containing ISAF type of carbon black with 30 wt.% of HSR showed high abrasion resistant properties against Du-Pont abrader, DIN abrader and different mining rock surfaces and also is found to be the toughest rubber against all types of rock. Coal is main abrader against the rubber under this study. 相似文献
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M. A. Lutfullin O. N. Shornikova K. V. Pokholok N. E. Sorokina V. V. Avdeev 《Inorganic Materials》2012,48(12):1175-1182
Using the anodic oxidation of graphite in Fe(NO3)3-HNO3 mixed electrolytes, followed by heat treatment, we obtained exfoliated graphite modified with iron oxides. All of the samples obtained were characterized by X-ray diffraction, M?ssbauer spectroscopy, and scanning electron microscopy. The results demonstrate that the proposed approach allows one to produce exfoliated graphite containing up to 14% Fe in the form of oxides and hydroxides, whose composition depends on the exfoliation temperature. 相似文献
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This paper describes numerical investigations conducted on filled rubbers. Some experimental data on stress relaxation tests carried out on various filled elastomers evidenced that increasing the content of rigid particles such as fillers or changes in the crystallization index, result in higher values of the stress relaxation rate. This result seems to indicate that higher rigid particle contents promote macroscopic viscoelastic strain. To better understand this effect, finite element analyses were carried out on axi-symmetric unit cells as well as unit cell for numerical homogenization with periodic computations. 相似文献