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Previous work on the characterization of interphase regions in thermosetting composite systems has focused on the inference of an interphase layer from effects noticed through macroscale mechanical and thermal testing. With the development of atomic force microscopy and active thermal probes for this technique, it is now possible to examine material thermal properties on a much smaller scale. Variations in microscale thermal properties of an aerospace‐grade thermosetting resin system were evaluated for carbon and glass fiber reinforcement, using the modulated local thermal analysis mode of a TA Instruments 2990 μTA. The variations observed clearly demonstrate the presence of a soft interphase layer in the glass material and underline the importance of fiber–matrix interactions during the formation of the interphase. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1643–1649, 2001 相似文献
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Castable particulate‐filled epoxy resins exhibiting excellent thermal conductivity have been prepared using hexagonal boron nitride (hBN) and cubic boron nitride (cBN) as fillers. The thermal conductivity of boron nitride filled epoxy matrix composites was enhanced up to 217% through silane surface treatment of fillers and multi‐modal particle size mixing (two different hBN particle sizes and one cBN particle size) prior to fabricating the composite. The measurements and interpretation of the curing kinetics of anhydride cured epoxies as continuous matrix, loaded with BN having multi‐modal particle size distribution, as heat conductive fillers, are highlighted. This study evidences the importance of surface engineering and multi‐modal mixing distribution applied in inorganic fillered epoxy‐matrix composite. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 相似文献
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石墨/NR导热复合材料的研究 总被引:1,自引:0,他引:1
分别采用可膨胀石墨、粉碎后的可膨胀石墨和膨胀石墨制备石墨/NR导热复合材料,研究石墨品种和用量对复合材料性能的影响.结果表明,随着石墨用量的增大,填充可膨胀石墨、粉碎后的可膨胀石墨和膨胀石墨复合材料的物理性能均有不同程度下降,填充膨胀石墨复合材料的热导率增大,填充可膨胀石墨或粉碎后可膨胀石墨复合材料的热导率先增大后减小.当石墨用量相同时,填充膨胀石墨复合材料的热导率高于填充可膨胀石墨或粉碎后的可膨胀石墨复合材料.石墨/NR复合材料压缩疲劳温升与热导率的正相关性较好. 相似文献
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以天然鳞片石墨为导热填料,E44型环氧树脂为基体,采用超声分散法制备天然鳞片石墨/环氧树脂复合导热材料.系统考察了天然鳞片石墨用量、石墨粒度和炭黑添加量等因素对复合材料导热性能的影响.结果表明:随着天然鳞片石墨用量增加,复合材料的导热系数增大,抗压强度先增加后减小;复合材料的导热系数随天然石墨粒径的增大而增大,抗压强度先减小后增加;在石墨/环氧树脂复合导热材料中添加不同用量的炭黑时,随着炭黑添加量的增加,复合材料的抗压强度增大,导热系数先增大后减小.制备天然鳞片石墨/环氧树脂复合导热材料的最佳配方为天然鳞片石墨用量45%,粒径≤270 μm,炭黑用量2%. 相似文献
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采用浇铸成型法制备碳化硅/环氧树脂(SiC/EP)导热复合材料,研究了SiC种类、粒径、用量和表面改性方法对SiC/EP复合材料的导热性能、力学性能和热性能等影响。结果表明:SiC/EP复合材料的导热系数随纳米级SiC用量增加而增大,当φ(纳米级SiC)=17.80%时,导热系数为0.954 6 W/(m.K);SiC/EP复合材料的弯曲强度和冲击强度随纳米级SiC用量增加均呈先升后降态势,当φ(纳米级SiC)=3.50%时,两者均达到最大值。SiC经表面改性后可有效提高复合材料的导热性能和力学性能,并且改性SiC的加入可有效降低EP的玻璃化转变温度。 相似文献
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《Journal of Adhesion Science and Technology》2013,27(1):829-846
An electrodeposition technique has been used for the modification of the fiber-matrix interphase in graphite fiber-epoxy composites. A coating of poly(styrene-co-maleic anhydride) (SMA) polymer was electrodeposited from an aqueous solution on AU graphite fibers used as electrodes in an electrolytic cell. Different electrocoating parameters were initially used to establish the optimum conditions to achieve thin uniform coatings suitable for functioning as interphases in composites reinforced by the coated fibers. The interfacial shear strength (IFSS), evaluated by a single-fiber composite technique, showed that the SMA coating resulted in an improvement of about 50% in IFSS compared with the commercially treated fibers (AS). This was achieved without sacrificing impact strength. Evidence of good epoxy penetration into the coating was obtained by the use of electron microprobe line scans for bromine across the diameter of a filament in a single fiber composite-the bromine introduced through the use of a brominated epoxy resin. The observed improvement in the fiber-matrix interfacial shear strengths is dependent on the co-monomer ratio in electrodeposited SMA. 相似文献
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Aluminum nitride‐single walled carbon nanotube nanocomposite with superior electrical and thermal conductivities 下载免费PDF全文
Amrita Chakravarty Ravindra Singh Sudakshina Roy Ujjal Chowdhury Sumantra Basu Sampad Kumar Biswas 《Journal of the American Ceramic Society》2017,100(8):3360-3364
Development of aluminum nitride (AlN)‐single walled carbon nanotube (SWCNT) ceramic‐matrix composite containing 1‐6 vol% SWCNT by hot pressing has been reported in this article. The composites containing 6 vol% SWCNT are dense (~99% relative density) and show high dc electrical conductivity (200 Sm?1) and thermal conductivity (62 Wm?1K?1) at room temperature. SWCNTs contain mostly metallic variety tubes obtained by controlled processing of the pristine tubes before incorporation into the ceramic matrix. Raman spectroscopy and field emission scanning electron microscopy (FESEM) of the fracture surface of the samples show the excellent survivability of the SWCNTs even after high‐temperature hot pressing. The results indicate the possibility of preparation of AlN nanocomposite for use in plasma devices and electromagnetic shielding. 相似文献
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Toshihiro Ishikawa Keiko Tsujikura Masaki Tanaka Naoto Nishida Atsuyuki Mitani 《International Journal of Applied Ceramic Technology》2020,17(6):2734-2743
MgO is industrially produced from seawater or dolomite as the raw material. MgO synthesized from seawater has a relatively low impurity concentration. However, these impurities strongly affect the fine structure and physical properties (especially the thermal conductivity) of MgO. In this research, the influence of impurity concentration on the MgO grain growth and its thermal conductivity was investigated. The processing conditions for MgO powder synthesis were optimized by a polymer complex method using magnesium nitrate hydrate, citric acid, ethylene diamine, and chemical compounds containing B, Ca, or Si, which are the main impurities of MgO produced from seawater. The morphology and phase composition of the MgO powders were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDS). The morphological changes and differences in the thermal conductivity of MgO crystalline systems containing impurities (B, Ca, and/or Si) were clarified, and the relationship between the fine structure of MgO crystals containing impurities and their thermal conductivities was described in detail. 相似文献
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A low‐disturbance nonequilibrium molecular dynamics algorithm applied to the determination of thermal conductivities 下载免费PDF全文
Filipe A. Furtado Charlles R. A. Abreu Frederico W. Tavares 《American Institute of Chemical Engineers》2015,61(9):2881-2890
A new nonequilibrium molecular dynamics algorithm is proposed for the determination of thermal conductivity and other transport properties. The proposed algorithm aims at diminishing the energy drift problem observed in this type of method while conserving linear momentum and being compatible with constrained molecules. The features of the proposed algorithm are evaluated by determining thermal conductivities of water at 323 K, n‐octane at 300 K, and argon close to its triple point, and by comparing these results with those obtained using established methods. The analysis of systems presenting diverse molecular characteristics allowed us to assess the usefulness of the proposed algorithm. The energy drift and temperature variation were reduced in the range of 10–80%, depending on the parameters of the proposed algorithm and the characteristics of the system. The determined thermal conductivities showed good agreement when compared to experimental and simulation data. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2881–2890, 2015 相似文献
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为了探究二维纳米材料的尺寸对复合相变材料储热特性的影响, 将膨胀石墨分别超声振荡10、30和90 min, 得到3种不同尺寸的石墨纳米片:GNS-10、GNS-30、GNS-90, 添加到十六醇中制备出纳米复合相变材料。利用SEM、XRD和Hot Disk等方法对其微观结构和性能进行表征和测试的同时, 对比研究了Maxwell、Bruggeman及Nielsen模型对热导率的计算结果。结果显示, 石墨纳米片尺寸越大, 对复合相变材料热导率的提升幅度越大。当GNS-10添加量为10%(质量分数)时, 热导率提升了约517%。Nielsen模型在形状因子A取100~180时可以较好地预测实验值。与大幅增长的热导率相比, 复合相变材料相变温度、相变焓的变化可忽略不计。此外, 石墨纳米片的加入明显缩短了储热材料的凝固速率, 有效热导率的提高是产生这种效果的主要原因。 相似文献
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Dong Huang Ruixuan Tan Ling Liu Chong Ye Shipeng Zhu Zhen Fan Peng Zhang Huang Wu Fei Han Hongbo Liu Jinshui Liu 《Journal of the European Ceramic Society》2021,41(8):4438-4446
The novel three dimensional highly thermal conductive carbon/carbon-silicon carbide (C/C-SiC) composite was successfully prepared using the mesophase-pitch-based carbon fibers and pyrocarbon as the thermal diffusion channels. The results show that the highly thermal conductive C/C-SiC composite with 221.1 W m?1K?1 in the ablation direction exhibits a smaller temperature gradient, and the surface temperature is 470 °C lower than that of the lowly thermal conductive C/C-SiC composite. The mass and linear ablation rates of the highly thermal conductive C/C-SiC composite are 0.56 mg·cm?2 s?1 and 0.11 μm·s?1, respectively. 相似文献
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无机填料的表面处理及其在导热天然橡胶复合材料中的应用 总被引:1,自引:0,他引:1
用季戊四醇、丙三醇和钛酸酯偶联剂分别对氧化铝、氧化镁和高岭土进行表面改性,并将改性填料填充天然橡胶(NR)制备了导热复合材料,考察了表面处理剂种类及其用量对无机填料的影响,并研究了季戊四醇改性氧化铝填充NR复合材料的硫化特性、物理机械性能和导热性能.结果表明,3种填料中季戊四醇的改性效果最好,且其用量为1.0~1.5份时对氧化铝的改性效果最佳;随着改性氧化铝填充量的增加,复合材料的最大转矩、300%定伸应力、拉伸强度和热导率均增大,当其用量为60份时,改性氧化铝填充NR复合材料的热导率比未填充NR复合材料提高了23.9%. 相似文献
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相变材料(PCMs)作为潜热储存和释放的介质,能够解决热能供需矛盾,从而缓解能源危机。纯相变材料具有能量密度高、温度范围广、能量输出稳定性强等优点,但其热导率低和在相变过程发生渗漏的缺点阻碍了其广泛的应用和发展。通过将PCMs与二维纳米片复合,PCMs热导率低和渗漏问题被有效解决。通过在导热机理方面进行详细阐述的基础上,综述了近几年来有关碳基二维纳米片、六方氮化硼(h-BN)纳米片、二硫化钼等复合储热材料的研究进展,为高性能二维纳米片基复合PCMs的设计提供一定的研究思路。 相似文献