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Artykuły w czasopismach na temat "Electrical Properties - Nanocomposites"
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Cho, Kie Yong, A. Ra Cho, Yun Jae Lee, Chong Min Koo, Soon Man Hong, Seung Sangh Wang, Ho Gyu Yoon i Kyung Youl Baek. "Enhanced Electrical Properties of PVDF-TrFE Nanocomposite for Actuator Application". Key Engineering Materials 605 (kwiecień 2014): 335–39. http://dx.doi.org/10.4028/www.scientific.net/kem.605.335.
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Carbon nanotubes (CNTs) coated by compatibilizer (P3HT-PMMA) imparted sta-ble dispersion in organic solvents and polymer matrix (P(VDF-TrFE)). The compatibility be-tween CNTs with P3HT-PMMA was con rmed by measuring Raman spectroscopy. CoatedCNTs were then blended with P(VDF-TrFE) (70:30 mol%) to obtain polymer nanocompositesby solution- casting process. Polymer nanocomposites showed enhanced electrical characteris-tics, as nanocomposites near the threshold of the transition between P(VDF-TrFE) insulatorand CNT conductor revealed great improvement of electrical conductivity up to 10-6 S/cmat 1 KHz. Electromechanical properties of the polymer nanocomposite were examined as afunction of electric eld.
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Abou El Fadl, Faten Ismail, Maysa A. Mohamed, Magida Mamdouh Mahmoud i Sayeda M. Ibrahim. "Studying the electrical conductivity and mechanical properties of irradiated natural rubber latex/magnetite nanocomposite". Radiochimica Acta 110, nr 2 (22.11.2021): 133–44. http://dx.doi.org/10.1515/ract-2021-1080.
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Abstract Nanocomposites have received voluminous interest due to the combination of unique properties of organic and inorganic component in one material. In this class, magnetic polymer nanocomposites are of particular interest because of the combination of excellent magnetic properties, stability, and good biocompatibility. This paper reports the preparation and characterization of nanocomposites films based on natural rubber in latex state (NRL) loaded with different concentrations of semiconducting magnetite nanoparticles (Fe3O4) (MNPs) (5, 10, 15, 20, and 30%). NRL (100%) and NRL/Fe3O4 nanocomposites were prepared by solution casting technique then, exposed to various irradiation doses (50, 70, 100 kGy).The nanocomposite’s morphological, and physical properties were investigated through various spectroscopic techniques such as Fourier-transformed infrared, X-ray diffraction, scanning electron, and transmission electron microscopies. The mechanical properties, including the tensile strength and elongation at break percentage (E b %) of the nanocomposites were also studied and compared with the 100% NRL films. Based on the results obtained from the mechanical study, it is found that the NRL/20% Fe3O4 nanocomposite film exhibited the highest tensile strength at 100 kGy. On the other hand, based on the conductivity study, it is found that, NRL/Fe3O4 nanocomposite with 10% magnetite exhibit the highest conductivity as the content of magnetite plays an important and effective role based on the high and homogeneous dispersity.
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Polsterova, Helena. "Dielectric Properties of Nanocomposites Based on Epoxy Resin". ECS Transactions 105, nr 1 (30.11.2021): 461–66. http://dx.doi.org/10.1149/10501.0461ecst.
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Nanocomposites are subject of research in many fields of science. Electrical technology focused on the study of electrical properties of nanocomposites including breakdown strength, relative permittivity, resistivity and other. This paper describes the results of measurement of electrical parameters of a nanocomposite at various temperatures. The nanocomposite matrix was casting epoxy resin and nanoparticles were made of TiO2 powder at different concentrations.
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Sabo, Y. T., D. E. A. Boryo, I. Y. Chindo i A. M. Auwal. "Nanocomposites transformed from polystyrene waste/antimony, barium and nickel oxides nanoparticles with improved thermal and electrical properties". Nigerian Journal of Chemical Research 26, nr 2 (5.02.2022): 117–27. http://dx.doi.org/10.4314/njcr.v26i2.7.
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In this experiment, the oxide nanoparticles were synthesized via chemical precipitation and the nanocomposites were produced using in situ polymerization method with varying nanoparticles contents ranged from 0.1 g to 1.0 g for electrical conductivity and from 0.05 g to 0.25 g for thermal conductivity. The electrical and thermal conductivities of nanocomposites were investigated and compared with the values obtained for untreated polystyrene. It was observed that the electrical and thermal properties were higher for the nanocomposites and increase with increasing nanoparticle concentrations in the samples. It can be observed that nanocomposite containing NiO nanoparticles gave a better electrical and thermal conductivity followed by nanocomposite containing BaO nanoparticles and nanocomposite containing Sb2O3 nanoparticles respectively. It can also be observed that nanocomposite containing NiO nanoparticle showed increase in rate of heat transfer from 1.60 W to 2.60 W, while nanocomposite containing BaO nanoparticles recorded increase in rate of heat transfer from 1.40 W to 2.45 W and nanoomposite containing Sb2O3 nanoparticle showed increase in rate of heat transfer from 1.07 W to 2.21 W, as concentration of nanoparticles increased from 0.05 g to 0.25 g respectively. Conclusively, with these results, the nanocomposite containing NiO nanoparticles gave a better thermal and electrical conductivity by having a better conducting filler network inside the matrix than nanocomposite containing BaO nanoparticles and nanocomposite containing Sb2O3 nanoparticles. It is recommended that during the production of polymer nanocomposite, PS/NiO, PS/BaO and PS/Sb2O3 nanocomposites could be used in electrically conductive devices as well as suitable materials for heat transfer applications.
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V. C. Morais, Manuel, Marco Marcellan, Nadine Sohn, Christof Hübner i Frank Henning. "Process Chain Optimization for SWCNT/Epoxy Nanocomposite Parts with Improved Electrical Properties". Journal of Composites Science 4, nr 3 (14.08.2020): 114. http://dx.doi.org/10.3390/jcs4030114.
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Electrically conductive nanocomposites present opportunities to replace metals in several applications. Usually, the electrical properties emerging from conductive particles and the resulting bulk values depend on the micro/nano scale morphology of the particle network formed during processing. The final electrical properties are therefore highly process dependent. In this study, the electrical resistivity of composites made from single-walled carbon nanotubes in epoxy was investigated. Three approaches along the processing chain were investigated to reduce the electrical resistivity of nanocomposites-the dispersion strategy in a three-roll mill, the curing temperature, and the application of electric fields during curing. It was found that a progressive increase in the shear forces during dispersion leads to a more than 50% reduction in the electrical resistivities. Higher curing temperatures of the nanocomposite resin also lead to a decrease of around 50% in resistivity. Furthermore, a scalable resin transfer molding set-up with gold-coated electrodes was developed and tested with different mold release agents. It has been shown that curing the material under electric fields leads to an electrical resistivity approximately an order of magnitude lower, and that the properties of the mold release agent also influence the final resistivity of different samples in the same batch.
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Ouis, Nora, Assia Belarbi, Salima Mesli i Nassira Benharrats. "Improvement of Electrical Conductivity and Thermal Stability of Polyaniline-Maghnite Nanocomposites". Chemistry & Chemical Technology 17, nr 1 (27.03.2023): 118–25. http://dx.doi.org/10.23939/chcht17.01.118.
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A new nanocomposite based on conducting polyaniline (PANI) and Algerian montmorillonite clay dubbed Maghnite is proposed to combine conducting and thermal properties (Mag). The PANI-Mag nanocompo-sites samples were made by in situ polymerization with CTABr (cetyl trimethyl ammonium bromide) as the clay galleries' organomodifier. In terms of the PANI-Mag ratio, the electrical and thermal properties of the obtained nanocomposites are investigated. As the amount of Maghnite in the nanocomposite increases, thermal stability improves noticeably, as measured by thermal gravimetric analysis. The electric conductivity of nanocomposites is lower than that of free PANI. As the device is loaded with 5 % clay, the conductivity begins to percolate and decreases by many orders of magnitude. The findings show that the conductivity of nanocomposites is largely independent of clay loading and dispersion.
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Abdulla, Estabraq T. "Synthesis and electrical properties of conductive polyaniline/ SWCNT nanocomposites". Iraqi Journal of Physics (IJP) 15, nr 34 (8.01.2019): 106–13. http://dx.doi.org/10.30723/ijp.v15i34.126.
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The synthesis of conducting polyaniline (PANI) nanocomposites containing various concentrations of functionalized single-walled carbon nanotubes (f-SWCNT) were synthesized by in situ polymerization of aniline monomer. The morphological and electrical properties of pure PANI and PANI/SWCNT nanocomposites were examined by using Fourier transform- infrared spectroscopy (FTIR), and Atomic Force Microscopy (AFM) respectively. The FTIR shows the aniline monomers were polymerized on the surface of SWCNTs, depending on the -* electron interaction between aniline monomers and SWCNTs. AFM analysis showed increasing in the roughness with increasing SWCNT content. The AC, DC electrical conductivities of pure PANI and PANI/SWCNT nanocomposite have been measured in frequency range (50Hz - 600KHz) and in the temperature range from (30 to 160K). The results show the electrical conductivity of the nanocomposite is higher than pure PANI.
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Alam, Rabeya Binta, Md Hasive Ahmad, S. M. Nazmus Sakib Pias, Eashika Mahmud i Muhammad Rakibul Islam. "Improved optical, electrical, and thermal properties of bio-inspired gelatin/SWCNT composite". AIP Advances 12, nr 4 (1.04.2022): 045317. http://dx.doi.org/10.1063/5.0089118.
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In this study, we report a facile route to synthesize gelatin-based Single-Walled Carbon Nanotube (gelatin/SWCNT) nanocomposites using a simple solution casting process and investigate the impact of SWCNT filler on the structural, surface morphological, optical, electrical, and thermal features. According to the Fourier transform infrared spectroscopy study, the addition of SWCNTs improves the interaction between gelatin and SWCNTs. The field emission scanning electron microscope images showed the presence of the fillers increased with the increment of SWCNT. The roughness of the samples increased caused by high interfacial interactions between Gel and SWCNTs. The nanocomposite’s optical bandgap was observed to be reduced from 2.1 to 1.9 eV as the SWCNT was varied from 0% to 0.5 vol. %. The addition of SWCNTs significantly boosted the DC electrical conductivity of the prepared samples by four orders of magnitude. The incorporation of SWCNT into the gelatin matrix was also observed to improve the nanocomposite's melting enthalpy and degree of crystallinity up to 94.5%. The gelatin/SWCNT nanocomposites were found to be decomposed completely in 4 days in the soil in an open environment.
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Kasım, Hasan, i Murat Yazıcı. "Electrical Properties of Graphene / Natural Rubber Nanocomposites Coated Nylon 6.6 Fabric under Cyclic Loading". Periodica Polytechnica Chemical Engineering 63, nr 1 (18.06.2018): 160–69. http://dx.doi.org/10.3311/ppch.12122.
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In the present study, an elastomeric nanocomposite was prepared by two roller mixing mill with the Natural Rubber (NR) and Nano Graphene Platelets (NGP). The Nylon 6.6 cord fabrics were laminated with the prepared NR/NGP nanocomposite layers. The NR/NGP composites and Nylon 6.6 cord fabric laminated nanocomposite plates were cured at 165 °C for 10 min under pressure. Nylon 6.6 fabric reinforced NR/NGP nanocomposites were electrically characterized under free and cyclic loading conditions. NGP addition to NR improved the electrical conductivity. Under cyclic loading produced nanocomposite and cord fabric layered plates showed periodical sensing behavior with same amplitude in each period.
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Wang, Shaojing, Peng Xu, Xiangyi Xu, Da Kang, Jie Chen, Zhe Li i Xingyi Huang. "Tailoring the Electrical Energy Storage Capability of Dielectric Polymer Nanocomposites via Engineering of the Host–Guest Interface by Phosphonic Acids". Molecules 27, nr 21 (25.10.2022): 7225. http://dx.doi.org/10.3390/molecules27217225.
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Polymer nanocomposites have attracted broad attention in the area of dielectric and energy storage. However, the electrical and chemical performance mismatch between inorganic nanoparticles and polymer leads to interfacial incompatibility. In this study, phosphonic acid molecules with different functional ligands were introduced to the surface of BaTiO3 (BT) nanoparticles to tune their surface properties and tailor the host–guest interaction between BT and poly(vinylideneflyoride-co-hexafluroro propylene) (P(VDF-HFP)). The dielectric properties and electrical energy storage capability of the nanocomposites were recorded by broadband dielectric spectroscopy and electric displacement measurements, respectively. The influence of the ligand length and polarity on the dielectric properties and electrical energy storage of the nanocomposites was documented. The nanocomposite with 5 vol% 2,3,4,5,6-pentafluorobenzyl phosphonic acid (PFBPA)-modified BT had the highest energy density of 12.8 J cm−3 at 400 MV m−1, i.e., a 187% enhancement in the electrical energy storage capability over the pure P(VDF-HFP). This enhancement can be attributed to the strong electron-withdrawing effect of the pentafluorobenzyl group of PFBPA, which changed the electronic nature of the polymer–particle interface. On the other hand, PFBPA improves the compatibility of the host–guest interface in the nanocomposites and decreases the electrical mismatch of the interface. These results provide new insights into the design and preparation of high-performance dielectric nanocomposites.
Rozprawy doktorskie na temat "Electrical Properties - Nanocomposites"
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Schiţco, Cristina. "Thermal and electrical properties of PVDF/Cu nanocomposites". Master's thesis, Universidade de Aveiro, 2011. http://hdl.handle.net/10773/7531.
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Mestrado em Ciência e Engenharia de MateriaisPoly(vinylidene fluoride) (PVDF) nanocomposites films with spherical and 1 Dimension (1D) copper nanoparticles as fillers were prepared; the morphology, dielectric properties, and thermal conductivity were studied. The role of dimensionality of the fillers was assessed and discussed. Spherical or nanowires copper nanoparticles were incorporated into the polymeric matrix up to 0.30 wt % via solution casting from dimethylformamide DMF, which acts as a good solvent for PVDF. The obtained films were shown to be porous when investigated by Scanning Electron Microscopy (SEM). The porosity of the films was eliminated by a hot pressing step. Fourier transform infrared (FTIR) and Raman spectroscopy investigations indicated the formation of γ-phase in the pure polymer as for polymer matrix for both spherical and nanowires copper nanoparticles loading. The presence of Cu in the polymer matrix was only detected for high nanoparticles contents by UV-Vis spectroscopy and X Ray Diffraction (XRD). The crystallization of the polymer was not significantly affected in the case of Cu spheres nanoparticles loading. For Cu nanowires, an increase of the degree of crystallization (ΔXc) with Cu loading was observed (pressed samples). The dielectric and thermal conductivity measurements showed a significant improvement of the dielectric constant and thermal conductivity compared to pure PVDF. When the loading of Cu nanoparticles equals to 0.30%, the dielectric constant and thermal conductivity of the nanocomposites incorporating spherical particles is ~20 at 103 Hz and 0.39 W/mK, respectively. However and particularly interesting this effect is more noticeable for Cu nanowires nanocomposites for which the dielectric constant and the thermal conductivity reached values of 24.4 at 103 Hz and 0.45 W/mK, respectively. These results, until now not reported in the literature, have a unique relevance for future applications of PVDF as electric stress control, electromagnetic shielding and high storage capability of the electric energy devices.
Neste trabalho foram preparados filmes nanocompósitos de poli (fluoreto de vinilideno) (PVDF) com nanoesferas e nanofios de cobre. Foram estudadas a morfologia, propriedades dieléctricas e condutividade térmica. O papel da dimensionalidade do enchimento (fillers) foi avaliado e discutido. As nanopartículas esféricas ou nanofios de cobre foram incorporados na matriz polimérica até 0,30% em peso, através da conformação de soluções de dimetilformamida (DMF). Os filmes obtidos mostraram-se porosos quando analisados por microscopia electrónica de varrimento (SEM). A porosidade dos filmes foi eliminada por uma etapa de prensagem a quente. Espectroscopias de Infravermelho (FTIR) e Raman indicaram a formação da fase γ na matriz polimérica para ambos os tipos de fillers, nano esferas e nanofios de cobre. A presença de Cu na matriz do polímero só foi detectada por espectroscopia UV-VIS e Difracção de raios X (XRD) para altos teores de nanopartículas. A cristalização do polímero não foi significativamente afectada no caso da carga com nanoesferas de Cu. Contudo, foi observada um aumento do grau de cristalização (ΔXc) com a carga para os nanofios de Cu (amostras prensadas). Medições da resposta eléctrica e térmica revelaram uma melhoria significativa da constante dieléctrica e da condutividade térmica em comparação com PVDF puro. Quando a carga de nanopartículas de Cu equivale a 0,30%, a constante dieléctrica e a condutividade térmica dos nanocompósitos com partículas esféricas é de aproximadamente 20 a 103 Hz e 0,39 W/mK, respectivamente. No entanto, e particularmente interessante, este efeito é mais evidente para os nanocompósitos com nanofios de Cu, para os quais a constante dieléctrica e a condutividade térmica atingem valores de 24,4 a 103 Hz e 0,45 W/mK, respectivamente. Estes resultados, até agora não reportados na literatura, são de relevância para futuras aplicações de PVDF em dispositivos controladores de stress eléctrico, de blindagem electromagnética e de alta capacidade de armazenamento de energia eléctrica.
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Lau, K. Y. "Structure and electrical properties of silica-based polyethylene nanocomposites". Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/358889/.
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The topic of polymer nanocomposites remains an active area of research in the dielectrics community, due to the unique electrical properties that these materials could exhibit. To explain the behaviour of these materials, the importance of clarifying the interfaces between nanoparticles and polymer matrices has been emphasised. However,understanding of the interface in nanocomposites is unsatisfactory and, consequently,many experimental results remain unexplained. This thesis reports on an investigation into a polyethylene nanocomposite system that contains varying amounts of nanosilica that differ with respect to their surface chemistry. The addition of nanosilica, even with different surface chemistries, was found to enhance the nucleation density of polyethylene and perturb the spherulitic development. While less organised lamellar structures would be expected to lead to a lower breakdown strength, this does not appearto be the case for the material systems considered here under alternating current (AC) fields. In addition, nanosilica filled polyethylene was found to absorb significantly more water than unfilled polyethylene, with the consequence that both the permittivity and the loss tangent increase with increasing duration of water immersion. However, appropriate surface treatment of nanosilica reduces the water absorption effect and modifies the dielectric response of the nanocomposites compared with those containing an equivalent amount of untreated nanosilica. Although water absorption may not be a technologically desirable characteristic, the results indicate that water molecules can act as effective dielectric probes of interfacial factors. Meanwhile, the direct current (DC) breakdown strength reduces with the inclusion of increasing amount of nanosilica in the polyethylene, but surface treatment of nanosilica improves the DC breakdown strength with respect to equivalent nanocomposites containing untreated nanosilica. Results from space charge studies reveal increased space charge accumulation in the presence of the untreated nanosilica and, upon surface treatment of the nanosilica, the charge development was suppressed in comparison with nanocomposites containing an equivalent amount of untreated nanosilica. This observation suggests that space charge accumulation and DC failure are related in these systems and it would seem that control of surface chemistry is particularly critical in connection with the use of nanocomposites in DC applications. Finally, the mechanisms underpinning the concept of filler functionalisation in nanocomposites were investigated via the use of different aliphatic chain length silane coupling agents, and the results show that long silane chains enhance the DC breakdown strength of the resulting nanocomposites. The possible further enhancement in DC breakdown strength is also highlighted. Overall, this thesis demonstrates how a nanoparticle’s interface chemistry can affect both the structure and the electrical properties of the resulting nanocomposites, and serves as an important foundation towards the engineering of nanocomposites as the reliable electricalinsulation materials of the future, through the understanding of the interface.
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Zhang, Guoqiang. "The Synthesis and Electrical Properties of Functional Polymer Nanocomposites". Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case149010222646324.
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Lim, Chee-Sern. "Mechanical and electrical properties of aligned carbon nanofiber/epoxy nanocomposites". Thesis, Wichita State University, 2010. http://hdl.handle.net/10057/3315.
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Carbon Nanofibers (CNFs) are high aspect ratio nanofillers that possess excellent
mechanical and electrical properties. Hence, CNFs have been incorporated into polymer to
fabricate nanocomposites with superior mechanical and electrical properties. Studies have shown
that nanocomposites with superior mechanical and electrical properties can be fabricated with
relatively low concentration of nanofillers by properly aligning them in polymer resins through
AC electric field. In this work, functionalized CNFs have been incorporated into a high-strength
epoxy-based resin and aligned into a preferential direction using AC electric field to tailor
aligned carboxylic-functionalized CNFs (O-CNFs) and amine-functionalized CNFs (A-CNFs)
reinforced polymeric nanocomposites.
Both mechanical and electrical properties were quantified in order to examine the effect
of addition and alignment of functionalized CNFs on the properties of final nanocomposites.
Optical images revealed negligible agglomeration before and after curing of nanocomposites, at
the same time, they showed alignment arrays of functionalized CNFs in the nanocomposites that
were subjected to AC electric field. Additionally, the configuration of alignment for low
concentration of aligned O-CNFs and A-CNFs filled nancomposites was slightly different
compare to aligned nanocomposites with high concentration possibly due to elevated localized
interaction of adjacent functionalized CNFs. An increase of 11.34% in compressive modulus and
8.36% in compressive strength were achieved when adding 3wt% and 4.5wt% of O-CNFs to the
base resin system, respectively. By comparing different concentration of aligned and non-aligned
A-CNFs reinforced nanocomposites correspondingly, it was found that the percentage change of
compressive modulus for aligned A-CNFs filled samples was two to three times higher than nonaligned
samples. Meanwhile, a four order magnitude of reduction in electrical resistivity to 10⁶ Ω.cm was
obtained by aligning the functionalized CNFs in the epoxy resin. Furthermore, the electrical
percolation threshold of aligned O-CNFs filled nanocomposites was estimated to be 0.75wt%. A
possible trend of electrical resistivity of aligned A-CNFs filled nanocomposites was extrapolated
up to 4.5wt% and suggested that the percolation threshold of electrical resistivity would occur at
0.75wt%, which is similar to aligned O-CNFs nanocomposites. Moreover, it is also suggested
that the electrical resistivity of 4.5wt% aligned A-CNFs filled nanocomposites would reduce to
10⁴ Ohm.cm range.Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.
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Maruzhenko, Oleksii. "Structure, thermal and electrical properties of nanocomposites with hybrid fillers". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI131.
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Isolante. On a étudié les processus de formation d'une structure ségrégée, qui conduisait à la formation d'une distribution ordonnée de particules dans une matrice polymère. Il est montré que dans le système ségrégé, la valeur du seuil de percolation φc est d'un ordre de grandeur inférieur à celui d'un composite présentant une distribution aléatoire des charge (2,95% vol. pour le composite ségrégé contre 24,8% vol. pour le composite à distribution aléatoire). Le seuil de percolation dans le cas d'un mélange de charges est très inférieur à la valeur calculée à l'aide de la règle des mélanges. Il est montré que les résultats expérimentaux de conductivité thermique ne révèlent pas de comportement de percolation et peuvent être décrits de façon satisfaisante par le modèle de Lichtenecker. La valeur du paramètre λf traduisant la conductivité thermique de la charge en tenant compte de l’interface charge/matrice est de 4,4 fois plus élevé pour les systèmes ségrégés que pour un composite à distribution aléatoire de particules. Il est montré que dans les systèmes ségrégés, les paramètres de blindage sont considérablement augmentés en raison de l'absorption provoquée par la réflexion interne sur les parois conductrices du réseau de charges conductrices. Il est établi que les charges de carbone constituent la base la plus efficace, ce qui garantit une absorption élevée des rayonnements électromagnétiques (REM) aux faibles concentrations. Il est avéré que le plus grand effet de blindage est observé pour un mélange de charges hybrides GNP/CNT (nanoplaques en graphite / nanotubes de carbone). L'effet de synergie s'explique par la meilleure interaction du REM avec le réseau hybride ramifiée formés par les charges, ce qui entraîne une absorption accrue du REM. Les systèmes à structure ségrégée à base d'élastomères présentent un effet piézorésistif prononcé avec une relation linéaire de déformation / modification de l'intensité du courant. L'étude de l'effet piézorésistif dans une large gamme de température (-40 / +50°С) a montré la stabilité des caractéristiques principales et la possibilité d'utiliser le composite dans une large gamme de températuresThe thesis determines the principles of the conductive phase structure formation in polymer composites containing conductive fillers, which will be different types of carbon fillers. The processes of segregated structure formation in which the particles of the filler are localized on the surfaces of polymer grains is studied. It is shown that the value of the percolation threshold φc for the segregated system is one order lower than in the composite with a random distribution of the filler 2.95 vol.% and 24.8 vol.%, respectively. The hybrid filler shows percolation threshold, much lower than the value calculated using the mixing rule. Experimental results of thermal conductivity for systems filled with anthracite, graphene and hybrid filler Gr/A do not reveal percolation behaviour and can be well described by the Lichtenecker model. It is shown that λf for segregated systems is 4.4 times higher than for a composite with a random distribution of filler particles. It is shown that in segregated systems the shielding parameters are significantly increased due to the absorption caused by the internal reflection on the conductive walls of the filler framework. Carbon fillers create the most effective basis that ensures a high absorption rate of EMI at low concentrations. It was found that the greatest shielding effect in the interaction of a composite with electromagnetic radiation was observed for the hybrid filler GNP/CNT (graphite nanoplatelets/carbon nanotubes). The synergistic effect is explained not by their higher electrical conductivity, but by the better interaction of the EMI with the developed hybrid framework of the filler, which causes increased absorption of the EMI. Systems with a segregated structure based on elastomer (ground rubber) with a polymer-adhesive and hybrid electroconductive nano-fillers exhibit a significant piezoresistive effect. The cyclic studies of electric response, depending on the applied external load, showed a linear relationship between composite deformation and current changes through the sample and demonstrate stable long-term stability. The study of the piezoresistive effect in a wide temperature range (-40 ÷ +50°C) showed the stability of the main characteristics and the possibility of exploiting the composite in a wide temperature range
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Noël, Amélie. "Electrical properties of film-forming polymer/graphene nanocomposites : Elaboration through latex route and characterization". Thesis, Saint-Etienne, EMSE, 2014. http://www.theses.fr/2014EMSE0767/document.
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Les dispersions de nanocomposite à base aqueuse sont produites pour des applications diverses telles que les adhésifs, les revêtements et plus récemment les encres. Ce projet consiste à réaliser des encres conductrices nanocomposites comprenant des particules de polymère (latex) à basse température de transition vitreuse, Tg, pour la formation de films à température ambiante, et des plaquettes de graphène, en raison de leurs excellentes propriétés conductrices. Les charges conductrices, appelées multi-feuillets de graphène, sont réalisées par broyage en voie aqueuse de graphite (1-10 µm) stabilisées par différents tensio-actifs et/ou stabilisants. Cette méthode sans solvant et à bas coût permet de produire des suspensions de multi-feuillets (1-10 feuillets) de graphène. Les particules de polymères utilisées sont synthétisées par polymérisation en émulsion de monomères acrylates. Dans un second temps, des mélanges physiques de suspensions de graphène et de latex acrylates ont permis d’obtenir des encres nanocomposites. L’ajout de graphène permet l’obtention d’un seuil de percolation à bas taux de charge et une nette amélioration des propriétés électriques et du renfort. Le diamètre des billes de latex a une influence importante sur ces propriétés et a également été étudié. Afin d’augmenter la stabilité des suspensions et les interactions graphène/latex, des nanocomposites structurés ont été synthétisés par polymérisation in situ en émulsion, miniemulsion ou dispersion en présence de graphène. Les excellentes propriétés électriques associées à leur flexibilité font de ces matériaux des candidats adaptés pour la réalisation d’encres conductrices pour impression sur textilePrinted electronics, particularly on flexible and textile substrates, raised a strong interest during the past decades. This project presents a procedure that provides a complete and consistent candidate for conductive inks based on a graphene/polymer nanocomposite material. It consists in the synthesis of conductive inks nanocomposites comprising polymer particles (latex) with low glass transition temperature, Tg, and graphene platelets, for the conductive properties. The conductive particles, named Nanosize Multilayered Graphene (NMG), are prepared by wet grinding delamination of micro-graphite suspensions stabilized by various surfactants and/or polymeric stabilizers. This solvent-free procedure allows the formation of NMG suspensions with low thickness (1-10 sheets). Polymer particles are synthetized by surfactant-free emulsion polymerization with acrylates monomers.Physical blending of latex particles and NMG platelets are performed to obtain conductive nanocomposites inks. Adding NMG induce a low percolation threshold and a sharp increase of the electrical and mechanical properties of the nanocomposites. Moreover, the polymer particles diameters have an impact on these properties.To increase the formation of a well-defined cellular microstructure, the nanocomposites are also synthetized by in situ polymerization in presence of NMG platelets, using emulsion, miniemulsion or dispersion polymerization. The excellent electrical properties of these nanocomposites associated to their flexibility make these materials suitable candidates for the production of conductive inks for textile printing applications
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MINNAI, CHLOE'. "OPTICAL AND ELECTRICAL PROPERTIES OF METAL POLYMER NANOCOMPOSITES FABRICATED WITH SUPERSONIC CLUSTER BEAM IMPLANTATION". Doctoral thesis, Università degli Studi di Milano, 2018. http://hdl.handle.net/2434/637068.
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Clusters are aggregates composed of a countable number of atoms or molecules, starting with the dimer and reaching, with a vaguely defined upper bound of several hundred thousand atoms, into that interesting size range.
Clusters have properties that are different from both atoms and bulk materials as in these small aggregates the surface-to-volume ratio is very large and hence the surface atoms, play a dominant role compared to the bulk ones.
By assembling preformed clusters, one can build nanostructured materials. These can be divided in two main categories: cluster assembled films and nanocomposites. In the former case nanoparticles are deposited on a substrate in the latter they are incorporated in a matrix, a polymer for instance. Nanostructured materials offer exciting pathway for the construction of macroscopic materials with designer-specified optical, electrical, and catalytic properties which reflect the ones of their building blocks.
The object of this thesis is the study of the optical and electrical properties of metal-polymer nanocomposites (MPNs) in response to mechanical deformation. Reflectance of MPNs is also exploited to develop reflective and bendable diffracting gratings which can be adapted to concave surfaces in order to add focusing power to the diffracting one.
A further study regards the evolution of the electrical resistance during the growing of the nanostructured materials on different substrates. Then, the electrical properties of the systems in response to a voltage applied are explored, to find if peculiar phenomena such as resistance switching could occur.
Recipes to fabricate robust and reproducible devices which exhibit controllable resistance switching were developed, both for cluster-assembled thin films and MPNs; in this latter case the possibility of controlling the switching activity with mechanical bending is demonstrated as well.
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DeGeorge, Vincent G. "Chemical Partitioning and Resultant Effects on Structure and Electrical Properties in Co-Containing Magnetic Amorphous Nanocomposites for Electric Motors". Research Showcase @ CMU, 2017. http://repository.cmu.edu/dissertations/885.
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chemical partitioning of Cobalt-containing soft magnetic amorphous and nanocomposite materials has been investigated with particular focus on its consequences on these materials’ nanostructure and electrical resistivity. Theory, models, experiment, and discussion in this regard are presented on this class of materials generally, and are detailed in particular on alloys of composition, (Fe65Co35)79.5+xB13Si2Nb4-xCu1.5, for X={0- 4at%}, and Co-based, Co76+YFe4Mn4-YB14Si2Nb4, for Y={0-4at%}. The context of this work is within the ongoing efforts to integrate soft magnetic metal amorphous and nanocomposite materials into electric motor applications by leveraging material properties with motor topology in order to increase the electrical efficiency and decrease the size, the usage of rare-earth permanent magnets, and the power losses of electric motors. A mass balance model derived from consideration of the partitioning of glass forming elements relates local composition to crystal state in these alloys. The ‘polymorphic burst’ onset mechanism and a Time-Temperature- Transformation diagram for secondary crystallization are also presented in relation to the partitioning of glass forming elements. Further, the intrinsic electrical resistivity of the material is related to the formation of virtual bound states due to dilute amounts of the glass forming elements. And lastly, a multiphase resistivity model for the effective composite resistivity that accounts for the amorphous, crystalline, and glass former-rich amorphous regions, each with distinct intrinsic resistivity, is also presented. The presented models are validated experimentally on the Co-containing alloys by Atom Probe Tomography performed through collaboration with Pacific Northwestern National Laboratory.
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Jung, de Andrade Mônica. "Study of electrical properties of 2- and 3-dimensional carbon nanotubes networks". Toulouse 3, 2010. http://thesesups.ups-tlse.fr/1288/.
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Des réseaux bi- et tridimensionnels de nanotubes de carbone (2D- et 3D-CNTNs) ont été préparés sur substrat de silice amorphe et dans une matrice silice. Les aptitudes de plusieurs types de CNTs (mono-, double- et multi-parois : SWCNTs, DWCNTs et MWCNTs) à former un réseau percolant ont été comparées par mesure de la conductivité électrique (EC) de suspensions dynamiques de ces CNTs dans le chloroforme. Les suspensions de SWCNTs présentent une EC normalisée maximale (3. 08 S. Cm2/g) d'où leur choix pour les 2D-CNTNs tandis que les suspensions de DWCNTs ont le plus faible seuil de percolation (0. 002-0. 06 vol. %) d'où leur choix pour les 3D CNTNs. Pour les 2D-CNTNs, des suspensions aqueuses de SWCNTs (avec surfactant et sonication par sonde (PS)) ont été déposées par trempage, filtration, spray et dépôt électrophorétique. La plupart des 2D-CNTNs forment un réseau percolant dont EC obéit à la loi de puissance (exposant d'environ 1,29). Leurs conductance de surface et transparence dans l'UV permettent leur utilisation dans les écrans d'affichage, les écrans tactiles, les tubes cathodiques et la dissipation des charges électrostatiques. Les CNTNs les plus lisses sont intéressants pour les cellules solaires. Les 3D-CNTNs (nanocomposites) ont été préparés par sol-gel avec des DWCNTs modérément fonctionnalisés (avec/sans séchage) dispersés par PS, puis densifiés par "spark-plasma sintering". La voie sèche conduit au plus faible seuil de percolation (0,35 vol. % DWCNT) alors que le matériau le plus conducteur de la voie humide présente une EC de 1,56 S/cm (6,43 vol. % DWCNT). Les EC sont suffisantes pour l'évacuation des charges électrostatiques ou pour servir d'éléments chauffantsTwo and three dimensional carbon nanotube networks (2D- and 3D-CNTNs) were prepared over silica glass substrate and in silica matrix, respectively. The aptitudes of various CNTs (single-, double- and multi-walled CNTs: SWCNTs, DWCNTs and MWCNTs, respectively) to form percolating CNTNs were compared by measurement of their electrical conductivity (EC) in dynamic suspensions in chloroform. The SWCNTs suspensions show the highest maximum normalized EC (3. 08 S. Cm2/g) while the DWCNTs ones have the lowest percolation thresholds (0. 002-0. 06 vol. %). This led to choose SWCNTs for 2D-CNTNs and DWCNTs for 3D ones. To produce 2D-CNTNs, SWCNTs aqueous suspensions (prepared with surfactant and probe sonication, PS) were deposited over the substrates through: dip-coating (DC), filtration (FM), spray-coating (SC) and electrophoretic deposition (ED). Most of the 2D-CNTNs formed a percolating CNTN whose EC follow the power law (exponent ~1. 29). Their surface conductance and UV transparency allow their use in displays, touch screens, shielding in cathode tubes and electrostatic dissipation. The smoothest CNTNs obtained by DC and ED are also interesting for solar cells. The 3D-CNTNs were prepared by sol-gel route using mildly functionalized DWCNTs (with/without dry step) dispersed with PS. The nanocomposites were fully densified by spark-plasma sintering. The "Dry" route allowed the lowest percolation threshold (0. 35 vol. % DWCNT), while the more conductive material from "Wet" route shows EC of 1. 56 S/cm (6. 43 vol. % DWCNTs). Besides the dispersion of CNTs could be improved, the achieved EC of these nanocomposites is high enough for their use in anti-electrostatic or heating applications
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Takele, Haile [Verfasser]. "Optical and electrical properties of metal-polymer nanocomposites prepared by vapor-phase co-evaporation / Haile Takele". Kiel : Universitätsbibliothek Kiel, 2009. http://d-nb.info/1019810459/34.
Pełny tekst źródłaKsiążki na temat "Electrical Properties - Nanocomposites"
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Wang, Qing, i Lei Zhu. Functional polymer nanocomposites for energy storage and conversion. Redaktorzy Wang Qing, Zhu Lei i American Chemical Society. Division of Polymeric Materials: Science and Engineering. Washington, D.C: American Chemical Society, 2010.
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Wang, Qing. Functional polymer nanocomposites for energy storage and conversion. Washington, D.C: American Chemical Society, 2010.
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ZnO bao mo zhi bei ji qi guang, dian xing neng yan jiu. Shanghai Shi: Shanghai da xue chu ban she, 2010.
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Huang, Xingyi, i Chunyi Zhi. Polymer Nanocomposites: Electrical and Thermal Properties. Springer, 2018.
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Huang, Xingyi, i Chunyi Zhi. Polymer Nanocomposites: Electrical and Thermal Properties. Springer, 2016.
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Huang, Xingyi, i Chunyi Zhi. Polymer Nanocomposites: Electrical and Thermal Properties. Springer London, Limited, 2016.
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Novel Nanocomposites: Optical, Electrical, Mechanical and Surface Related Properties. MDPI, 2021. http://dx.doi.org/10.3390/books978-3-0365-2248-7.
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Ayyar, Manikandan, Anish Khan, Abdullah Mohammed Ahmed Asiri i Imran Khan. Magnetic Nanoparticles and Polymer Nanocomposites: Structural, Electrical and Optical Properties and Applications [Volume 2]. Elsevier Science & Technology, 2023.
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Ayyar, Manikandan, Anish Khan, Abdullah Mohammed Ahmed Asiri i Imran Khan. Magnetic Nanoparticles and Polymer Nanocomposites: Structural, Electrical and Optical Properties and Applications, Volume 2. Elsevier Science & Technology, 2023.
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Araújo, Ana Cláudia Vaz de. Síntese de nanopartículas de óxido de ferro e nanocompósitos com polianilina. Brazil Publishing, 2021. http://dx.doi.org/10.31012/978-65-5861-120-2.
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In this work magnetic Fe3O4 nanoparticles were synthesized through the precipitation method from an aqueous ferrous sulfate solution under ultrasound. A 23 factorial design in duplicate was carried out to determine the best synthesis conditions and to obtain the smallest crystallite sizes. Selected conditions were ultrasound frequency of 593 kHz for 40 min in 1.0 mol L-1 NaOH medium. Average crystallite sizes were of the order of 25 nm. The phase obtained was identified by X-ray diffractometry (XRD) as magnetite. Scanning electron microscopy (SEM) showed polydisperse particles with dimensions around 57 nm, while transmission electron microscopy (TEM) revealed average particle diameters around 29 nm, in the same order of magnitude of the crystallite size determined with Scherrer’s equation. These magnetic nanoparticles were used to obtain nanocomposites with polyaniline (PAni). The material was prepared under exposure to ultraviolet light (UV) or under heating, from dispersions of the nanoparticles in an acidic solution of aniline. Unlike other synthetic routes reported elsewhere, this new route does not utilize any additional oxidizing agent. XRD analysis showed the appearance of a second crystalline phase in all the PAni-Fe3O4 composites, which was indexed as goethite. Furthermore, the crystallite size decreases nearly 50 % with the increase in the synthesis time. This size decrease suggests that the nanoparticles are consumed during the synthesis. Thermogravimetric analysis showed that the amount of polyaniline increases with synthesis time. The nanocomposite electric conductivity was around 10-5 S cm-1, nearly one order of magnitude higher than for pure magnetite. Conductivity varied with the amount of PAni in the system, suggesting that the electric properties of the nanocomposites can be tuned according to their composition. Under an external magnetic field the nanocomposites showed hysteresis behavior at room temperature, characteristic of ferromagnetic materials. Saturation magnetization (MS) for pure magnetite was ~ 74 emu g-1. For the PAni-Fe3O4 nanocomposites, MS ranged from ~ 2 to 70 emu g-1, depending on the synthesis conditions. This suggests that composition can also be used to control the magnetic properties of the material.
Części książek na temat "Electrical Properties - Nanocomposites"
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Fothergill, J. C. "Electrical Properties". W Dielectric Polymer Nanocomposites, 197–228. Boston, MA: Springer US, 2009. http://dx.doi.org/10.1007/978-1-4419-1590-0_7.
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Fothergill, J. C. "Electrical Properties". W Dielectric Polymer Nanocomposites, 197–228. Boston, MA: Springer US, 2009. http://dx.doi.org/10.1007/978-1-4419-1591-7_7.
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Saini, Parveen. "Electrical Properties and Electromagnetic Interference Shielding Response of Electrically Conducting Thermosetting Nanocomposites". W Thermoset Nanocomposites, 211–37. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2013. http://dx.doi.org/10.1002/9783527659647.ch10.
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Costa, L. C. "Microwave Electrical Properties of Nanocomposites". W Nanoscience Advances in CBRN Agents Detection, Information and Energy Security, 227–38. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9697-2_23.
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Nizamuddin, Sabzoi, Sabzoi Maryam, Humair Ahmed Baloch, M. T. H. Siddiqui, Pooja Takkalkar, N. M. Mubarak, Abdul Sattar Jatoi i in. "Electrical Properties of Sustainable Nano-Composites Containing Nano-Fillers: Dielectric Properties and Electrical Conductivity". W Sustainable Polymer Composites and Nanocomposites, 899–914. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-05399-4_30.
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Khanam, P. Noorunnisa, Deepalekshmi Ponnamma i M. A. AL-Madeed. "Electrical Properties of Graphene Polymer Nanocomposites". W Graphene-Based Polymer Nanocomposites in Electronics, 25–47. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-13875-6_2.
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Indolia, Ajay Pal, Malvika Chaudhary, M. S. Gaur i Sobinder Singh. "Electrical Properties of PU/CdS Nanocomposites". W Recent Advances in Metrology, 343–51. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-2468-2_37.
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Gunasekaran, Vijayasri, Mythili Narayanan, Gurusamy Rajagopal i Jegathalaprathaban Rajesh. "Electrical and Dielectric Properties: Nanomaterials". W Handbook of Magnetic Hybrid Nanoalloys and their Nanocomposites, 783–800. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-90948-2_25.
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Gunasekaran, Vijayasri, Mythili Narayanan, Gurusamy Rajagopal i Jegathalaprathaban Rajesh. "Electrical and Dielectric Properties: Nanomaterials". W Handbook of Magnetic Hybrid Nanoalloys and their Nanocomposites, 1–18. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-34007-0_25-1.
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Tsekmes, Alex, Peter Morshuis i Gary C. Stevens. "Chapter 8 Electrical Properties of Polymer Nanocomposites". W Tailoring of Nanocomposite Dielectrics, 218–42. Penthouse Level, Suntec Tower 3, 8 Temasek Boulevard, Singapore 038988: Pan Stanford Publishing Pte. Ltd., 2016. http://dx.doi.org/10.1201/9781315201535-9.
Pełny tekst źródłaStreszczenia konferencji na temat "Electrical Properties - Nanocomposites"
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Ngabonziza, Yves, Jackie Li i Carol F. Barry. "Electrical Conductivity and Elastic Properties of MWCNT-PP Nanocomposites". W ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-68431.
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Electrical and elastic properties of multiwalled carbon nanotubes (MWCNTs) reinforced polypropylene (PP) nanocomposites were studied experimentally and theoretically. The MWCNT-PP nanocomposites samples with a range of 0 to 12 wt% MWCNT were injection molded using different injection velocities. These nanocomposites were characterized for their electrical resistance using 2-Probe measurement and their tensile properties. Parallel to the experimental investigation, a percolation theory was applied to study the electrical conductivity of the nanocomposite system in terms of content of nanotubes and injection rate. Both Kirkpatrick [1] and McLachlan [2] models were used to determine the transition from low conductivity to high conductivity which designates as percolation threshold. Both experimental and modeling results have shown that the electrical conductivity increased suddenly as the content of MWNTs was close to percolation threshold of 3.8 wt%. The injection speed also showed an effect on electrical conductivity of the composites. In addition, several micromechanical models were applied to elucidate the elastic properties of the nanocomposites. The results indicate that the interphase between the carbon nanotubes and polymers plays an important role in determining elastic modulus of the system.
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Minnich, Austin, i Gang Chen. "Modeling the Thermoelectric Properties of Nanocomposites". W ASME 2008 3rd Energy Nanotechnology International Conference collocated with the Heat Transfer, Fluids Engineering, and Energy Sustainability Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/enic2008-53003.
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Modeling the thermoelectric properties of nanocomposites is difficult due to the complex grain boundary scattering processes which scatter both electrons and phonons. In this work we describe a code we developed which numerically calculates the electrical and thermal properties of bulk and nanocomposite thermoelectric materials using the Boltzmann equation under the relaxation time approximation. The code is capable of calculating all the relevant thermoelectric properties over a wide range of temperatures, doping concentrations, and compositions, allowing for a full characterization of the material. We model nanocomposites by incorporating a grain boundary scattering rate based on a simple model we developed and models in the literature. The code and grain boundary scattering models are validated on bulk data and data from nano-SiGe, and are then applied to other candidate thermoelectric materials to see if they would be good candidates for nanocomposites. The analysis shows that GaAs might be promising as a nanocomposite thermoelectric material.
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Reddy, R. J., R. Asmatulu i W. S. Khan. "Electrical Properties of Recycled Plastic Nanocomposites Produced by Injection Molding". W ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-40259.
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Plastic recycling is a recovery process of waste plastics to make new products into different forms. Plastics are usually sorted based on their resin identification codes before the recycling and melting processes. Although the recycling rate of plastics is significantly high, properties and economical value of the recycled plastics are fairly low, which in turn limits the use of recycled plastics in the market. In the present study, high density polyethylene (HDPE) in the form of pellets was dissolved in toluene, and then nanoscale graphene inclusions at different loadings (e.g., 0%, 0.25%, 0.5%, 1%, 2% and 4%) were added into the polymeric solutions. The remaining solvent was removed from the nanocomposite before the injection molding process. The injection molding process was conducted on the chopped recycled plastics associated with graphene loadings. The dielectric and electric properties of plastic nanocomposites were studied in detail. The test results showed that the dielectric properties were slightly improved by the addition of inclusions, which may be due to the non-polar nature of HDPE and/or residues in the recycled plastics. However, electrical conductivities of nanocomposites were significantly increased because of the improved electrical conduction, polarization and electron mobility at room temperature.
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Ngabonziza, Yves, i Jackie Li. "Electrical Conductivity and Elastic Properties of Carbon Nanotube Reinforced Polycarbonate Nanocomposites". W ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-62685.
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In the past years, carbon nanotubes and their composites have been intensively studied due to their extremely high strength and high electrical and thermal conductivities. However, to be able to use CNT-reinforced composites as structural materials in real applications, more cost-efficient processing methods should be adopted and the properties of such nanocomposites need to be further analyzed. Here we investigate the electrical and elastic properties of multi-walled carbon nanotubes (MWCNT) reinforced polycarbonate (PC) nanocomposites produced by injection molding which has been widely used in industrial plastic production. Nanocomposite samples with MWCNT ranging from 0 to 7wt% were tested for both electrical conductivity using a 2-probe measurement and mechanical properties under tensile loading. It has been found that the electrical conductivity depends on both injection velocity and the CNT content while the elastic properties of the nanocomposites only depend on the CNT content. Besides the experimental testing, a percolation theory and micromechanics models have been applied to determine the electrical conductivity percolation threshold and the effective elastic modulus of the nanocomposites in terms of CNT contents. The results are compared with our experimental data. It shows that a percolation threshold is around 1.8wt% of MWCNT. The evaluation of elastic properties using micromechanics models not only indicates the influence of MWCNT on elastic properties but also the presence of an interphase between the CNT and PC matrix.
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Enomoto, Hiroyuki, Masayuki Kawaguchi, Nipaka Sukpirom i Michael M. Lerner. "Electrical properties of polymer/ MX 2 nanocomposites". W International Symposium on Optical Science and Technology, redaktor Naomi J. Halas. SPIE, 2002. http://dx.doi.org/10.1117/12.450467.
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Oskouyi, Amirhossein B., Uttandraman Sundararaj i Pierre Mertiny. "A Numerical Model to Study the Effect of Temperature on Electrical Conductivity of Polymer-CNT Nanocomposites". W ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-62602.
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In this study the effect of the temperature on the electrical conductivity of nanocomposites with carbon nanotube (CNT) fillers was investigated. A three-dimensional continuum Monte Carlo model was developed and employed first to form a CNT percolation network. CNT fillers were randomly generated and dispersed in a cubic representative volume element. Periodic boundary conditions were applied in this model to minimize size effects while decreasing computational cost. CNT fibers that connected electrically to each other through electron hopping were recognized and grouped as clusters. In addition to tunneling resistance, the effect of intrinsic CNT resistivity was considered. A three-dimensional resistor network was subsequently developed to evaluate nanocomposite electrical properties. Modeling employing the finite element method was conducted to evaluate the electrical conductivity of the percolation network. Considering the determining role of tunneling resistance on electrical conductivity of CNT based nanocomposites, as well as results obtained from experimental studies, temperature was expected to play an important role in nanocomposite electrical properties. The effect of temperature on electrical conductivity of CNT nanocomposites was thus investigated through employing the developed Monte Carlo and finite element models. Other aspects, including the electrical behavior of the polymer, tunneling resistivity and the intrinsic resistivity of CNT were considered in this study as well. The comprehensiveness of the developed modeling approach enables an evaluation of results in conjunction with experimental data in future works.
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Herren, Blake, Mrinal C. Saha, M. Cengiz Altan i Yingtao Liu. "Effects of Rapid Microwave-Curing on Mechanical and Piezoresistive Sensing Properties of Elastomeric Nanocomposites". W ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23175.
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Abstract Carbon nanotubes (CNTs) have the unique ability to absorb microwave radiation and efficiently transfer the energy into substantial heat. When adequately dispersed in a thermoset polymer, such as polydimethylsiloxane (PDMS), the nanocomposite can be fully cured in seconds in a microwave oven rather than in hours in a convection oven. In this paper, cylindrical PDMS nanocomposites containing well-dispersed CNTs are fabricated by either microwave-curing or conventional thermal-curing. The mechanical, electrical, and piezoresistive properties of the fabricated samples are compared to understand the effects of different curing methods. Microwave-cured nanocomposites exhibit a significantly reduced compressive modulus for different CNT loadings. In addition, the electrical conductivity of microwave-cured nanocomposites is significantly enhanced over the thermally-cured counterparts. Experimental results demonstrate that the one-step microwave-curing procedure can improve the electrical conductivity of 1 wt% nanocomposites by almost 150 % over thermal-curing. However, their piezoresistive sensitivity remains remarkably similar, showing the potential for microwave-curing to replace thermal-curing for the manufacturing of highly flexible CNT-based nanocomposites.
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Thaler, Dominic, Nahal Aliheidari i Amir Ameli. "Electrical Properties of Additively Manufactured Acrylonitrile Butadiene Styrene/Carbon Nanotube Nanocomposite". W ASME 2018 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/smasis2018-8002.
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Additive manufacturing is an emerging method to produce customized parts with functional materials without big investments. As one of the common additive manufacturing methods, fused deposition modeling (FDM) uses thermoplastic-based feedstock. It has been recently adapted to fabricate composite materials too. Acrylonitrile butadiene styrene (ABS) is the most widely used material as FDM feedstock. However, it is an electrically insulating polymer. Carbon Nanotubes (CNTs) on the other hand are highly conductive. They are attractive fillers because of their high aspect ratio, and excellent mechanical and physical properties. Therefore, a nanocomposite of these two materials can give an electrically conductive material that is potentially compatible with FDM printing. This work focuses on the investigation of the relationships between the FDM process parameters and the electrical conductivity of the printed ABS/CNT nanocomposites. Nanocomposite filaments with CNT contents up to 10wt% were produced using a twin-screw extruder followed by 3D printing using FDM method. The starting material was pellets from a masterbatch containing 15 wt% CNT. Compression-molded samples of ABS/CNT were also prepared as the bulk baselines. The effects of CNT content and nozzle size on the through-layer and in-layer electrical conductivity of the printed nanocomposites were analyzed. Overall, a higher percolation threshold was observed in the printed samples, compared to that of the compression-molded counterparts. This resulted in the conductivity of the printed samples that is at least one order of magnitude lower. Moreover, at CNT contents up to 5 wt%, the in-layer conductivity of the printed samples was almost two orders of magnitudes higher than that in the through-layer direction. In ABS/3 wt% CNT samples, the through-layer conductivity continuously decreased as the nozzle diameter was decreased from 0.8 mm to 0.35 mm. These variations in the electrical conductivity were explained in terms of the CNT alignment, caused by the extrusion process during the print, quality of interlayer bonding during deposition, and the voids created due to the discrete nature of the printing process.
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Li, Hua, i Gang Li. "Computational Analysis of Strain Effects on Electrical Transport Properties of Crystalline Nanocomposite Thin Films". W ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64641.
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In this work, we model the strain effects on the electrical transport properties of Si/Ge nanocomposite thin films. We utilize a two-band k·p theory to calculate the variation of the electronic band structure as a function of externally applied strains. By using the modified electronic band structure, electrical conductivity of the Si/Ge nanocomposites is calculated through a self-consistent electron transport analysis, where a nonequilibrium Green’s function (NEGF) is coupled with the Poisson equation. The results show that both the tensile uniaxial and biaxial strains increase the electrical conductivity of Si/Ge nanocomposite. The effects are more evident in the biaxial strain cases.
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Han, Zhi-dong, Changjun Diao, Ying Li i Hong Zhao. "Thermal properties of LDPE/silica nanocomposites". W 2006 IEEE Conference on Electrical Insulation and Dielectric Phenomena. IEEE, 2006. http://dx.doi.org/10.1109/ceidp.2006.311931.
Pełny tekst źródłaRaporty organizacyjne na temat "Electrical Properties - Nanocomposites"
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Barnes, Eftihia, Jennifer Jefcoat, Erik Alberts, Hannah Peel, L. Mimum, J, Buchanan, Xin Guan i in. Synthesis and characterization of biological nanomaterial/poly(vinylidene fluoride) composites. Engineer Research and Development Center (U.S.), wrzesień 2021. http://dx.doi.org/10.21079/11681/42132.
Pełny tekst źródłaStreszczenie:
The properties of composite materials are strongly influenced by both the physical and chemical properties of their individual constituents, as well as the interactions between them. For nanocomposites, the incorporation of nano-sized dopants inside a host material matrix can lead to significant improvements in mechanical strength, toughness, thermal or electrical conductivity, etc. In this work, the effect of cellulose nanofibrils on the structure and mechanical properties of cellulose nanofibril poly(vinylidene fluoride) (PVDF) composite films was investigated. Cellulose is one of the most abundant organic polymers with superior mechanical properties and readily functionalized surfaces. Under the current processing conditions, cellulose nanofibrils, as-received and 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) oxidized, alter the crystallinity and mechanical properties of the composite films while not inducing a crystalline phase transformation on the 𝛾 phase PVDF composites. Composite films obtained from hydrated cellulose nanofibrils remain in a majority 𝛾 phase, but also exhibit a small, yet detectable fraction of 𝛼 and ß PVDF phases.