Littérature scientifique sur le sujet « Composite nanofibers »
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Articles de revues sur le sujet "Composite nanofibers"
1
Chang, Zhen Jun. « Development of a Polyurethane Nanocomposite Reinforced with Carbon Nanotube Composite Nanofibers ». Materials Science Forum 688 (juin 2011) : 41–44. http://dx.doi.org/10.4028/www.scientific.net/msf.688.41.
Texte intégralRésumé :
Functionalized carbon nanotubes (CNTs) composite nanofibers with high melting point polyurethane (PUH) as matrix were fabricated by electrospinning method, which were later stacked alternately with low melting point polyurethane (PUL) films into composite nanofiber reinforced composites through a hot press treatment. The tensile modulus (30 wt.% composite nanofibers) reaches 54.3 MPa, 187% higher than that pure PUL film.
2
Liu, Ning, et Lilin Jiang. « Effect of microstructural features on the thermal conducting behavior of carbon nanofiber–reinforced styrene-based shape memory polymer composites ». Journal of Intelligent Material Systems and Structures 31, no 14 (20 juin 2020) : 1716–30. http://dx.doi.org/10.1177/1045389x20932216.
Texte intégralRésumé :
This article presents a novel hierarchical micromechanics approach to carefully investigate the thermal conductivities of styrene-based shape memory polymer composites containing carbon nanofibers. The research is mainly focused on the simulation of carbon nanofiber/shape memory polymer interfacial thermal resistance and carbon nanofiber agglomeration as two critical microstructural features of carbon nanofiber–shape memory polymer composite materials. The computed results are compared with the available experimental measurements. It is found that both of those microstructural factors along with carbon nanofiber non-straight shape significantly affecting the thermal conducting behavior must be incorporated in the analysis to have a more realistic prediction. The thermal conductivity of carbon nanofiber–reinforced shape memory polymer composites reduces significantly due to the effects of carbon nanofiber/shape memory polymer interfacial resistance and carbon nanofiber agglomeration and waviness. It is suggested to uniformly disperse carbon nanofibers into the shape memory polymers and reduce interfacial resistance for improving the carbon nanofiber–styrene composite thermal properties. In addition, the present study reveals that the effective thermal conductivities of the shape memory polymer composites reinforced by aligned carbon nanofibers are greatly enhanced over those of the shape memory polymer composites containing randomly dispersed carbon nanofibers. The effects of percentage, waviness parameters, degree of agglomeration, material properties, length and diameter of carbon nanofibers as well as interfacial thermal resistance value on the thermal behavior of carbon nanofiber–reinforced styrene-based shape memory polymer composites are investigated.
3
Gao, Dawei, Hui Qiao, Qingqing Wang, Yibing Cai et Qufu Wei. « Structure, Morphology and Thermal Stability of Porous Carbon Nanofibers Loaded with Cobalt Nanoparticles ». Journal of Engineered Fibers and Fabrics 6, no 4 (décembre 2011) : 155892501100600. http://dx.doi.org/10.1177/155892501100600402.
Texte intégralRésumé :
Porous carbon/cobalt (C/Co) composite nanofibers with diameters of 200–300 nm were prepared by electrospinning and subsequent carbonization processes. Two polymer solutions of polyacrylonitrile (PAN), polyvinyl pyrrolidone (PVP), and Co (CH3COOH) 2 (Co (OAc) 2) were used as C/Co composite nanofiber precursors. The study revealed that C/Co composite nanofibers were successfully prepared and cobalt particles with diameters of 20–30 nm were uniformly scattered in the carbon nanofibers. It was also observed that clear fibrous morphology with grainlike particles and good structural integrity were still maintained after calcination. The TGA analysis indicated the improved thermal stability properties of the composite nanofibers. The Brunauer-Emmett-Teller (BET) analysis indicated that C/Co composites nanofibers with meso-pores possessed larger specific surface area than that of carbon nanofibers.
4
Toriello, Mariela, Morteza Afsari, Ho Kyong Shon et Leonard D. Tijing. « Progress on the Fabrication and Application of Electrospun Nanofiber Composites ». Membranes 10, no 9 (28 août 2020) : 204. http://dx.doi.org/10.3390/membranes10090204.
Texte intégralRésumé :
Nanofibers are one of the most attractive materials in various applications due to their unique properties and promising characteristics for the next generation of materials in the fields of energy, environment, and health. Among the many fabrication methods, electrospinning is one of the most efficient technologies which has brought about remarkable progress in the fabrication of nanofibers with high surface area, high aspect ratio, and porosity features. However, neat nanofibers generally have low mechanical strength, thermal instability, and limited functionalities. Therefore, composite and modified structures of electrospun nanofibers have been developed to improve the advantages of nanofibers and overcome their drawbacks. The combination of electrospinning technology and high-quality nanomaterials via materials science advances as well as new modification techniques have led to the fabrication of composite and modified nanofibers with desired properties for different applications. In this review, we present the recent progress on the fabrication and applications of electrospun nanofiber composites to sketch a progress line for advancements in various categories. Firstly, the different methods for fabrication of composite and modified nanofibers have been investigated. Then, the current innovations of composite nanofibers in environmental, healthcare, and energy fields have been described, and the improvements in each field are explained in detail. The continued growth of composite and modified nanofiber technology reveals its versatile properties that offer alternatives for many of current industrial and domestic issues and applications.
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Bayat, Masoumeh, Heejae Yang et Frank Ko. « Effect of iron oxide nanoparticle size on electromagnetic properties of composite nanofibers ». Journal of Composite Materials 52, no 13 (20 septembre 2017) : 1723–36. http://dx.doi.org/10.1177/0021998317732139.
Texte intégralRésumé :
Electrically conductive and magnetically permeable carbon nanofiber-based composites were developed using the electrospinning with subsequent heat treatment. The composite nanofiber contains a variable composition of magnetite nanoparticles with two different size regimes, ranging from superparamagnetic (10–20 nm) to ferromagnetic (20–30 nm). The composite nanofibers are then characterized using Scanning/Transmission Electron Microscopy, X-Ray Diffractometry, Raman Spectroscopy, four-point probe, and a Superconducting Quantum Interference Device. Electromagnetic Interference Shielding Effectiveness of pristine carbon nanofibers as well as electromagnetic composite nanofibers are examined in the X-band frequency region. Higher degree of graphitization, electrical conductivity, and magnetic strength are obtained for nanocomposites containing larger magnetite nanoparticles (20–30 nm). A transition from superpartamagnetic to ferromagnetic characteristics is observed during nanocomposite processing. Electromagnetic Interference Shielding Effectiveness of as high as 68 dB (in the working frequency of 10.4 GHz) is observed for composite nanofibers fabricated with larger magnetite nanoparticles carbonized at 900℃.
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Tan, Noel Peter B., Luis K. Cabatingan et Kramer Joseph A. Lim. « Synthesis of TiO2 Nanofiber by Solution Blow Spinning (SBS) Method ». Key Engineering Materials 858 (août 2020) : 122–28. http://dx.doi.org/10.4028/www.scientific.net/kem.858.122.
Texte intégralRésumé :
Synthesis of ceramic nanofibers is commonly carried out through electrospinning method. However, with the emergence of solution blow spinning (SBS) technology, spinning of nanofiber and its composites has resulted in a more straightforward and commercially scalable process. In this study, ceramic nanofibers (i.e., TiO2 nanofibers) were synthesized through SBS followed by calcination. Three critical parameters were investigated (i.e., precursor concentration, calcination temperature and time) to produce ready-to-use composite membranes and pure ceramic nanofibers. Characterizations of ceramic membranes and pure nanofibers include scanning electron microscope (SEM) analysis and energy dispersive x-ray (EDX) for elemental component analysis. Insights on the transformation of composite membranes into pure ceramic nanofibers and the role of calcination are also discussed.
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XIANHUA, Z., F. XIANGWEI, Y. BIN, L. FAN, C. LINA et Z. CENGCENG. « STUDY ON PREPARATION AND PROPERTIES OF PVA/AgNPs COMPOSITE NANOFIBER MASK MATERIAL ». Digest Journal of Nanomaterials and Biostructures 15, no 2 (avril 2020) : 299–309. http://dx.doi.org/10.15251/djnb.2020.152.299.
Texte intégralRésumé :
In this paper, the preparation and properties of polyvinyl alcohol (PVA)/silver nanoparticles (AgNPs) composite nanofiber mask material were studied. Firstly, PVA spinning solution was prepared, and PVA nanofibers with different mass fractions (5 wt%, 7 wt%, 8 wt%, 9 wt% and 11 wt%) were prepared by electrospinning technology. The morphology of PVA nanofibers was observed under electron microscope, and the results showed that 8 wt% PVA nanofibers had the best morphology. AgNPs with different mass fractions (0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt% and 0.06 wt%) were dispersed in pure water and blended with 8 wt% PVA solution to prepare PVA/AgNPs composite nanofibers by electrospinning. The effects of different mass fractions of AgNPs on the morphology of PVA/AgNPs composite nanofibers were analyzed. Infrared spectroscopy and X-ray diffraction were used to test the PVA/AgNPs composite nanofibers. PVA/AgNPs composite nanofiber mask fabric was prepared by using activated carbon nonwoven fabric as substrate. The filterability, air permeability and moisture permeability of PVA/AgNPs composite nanofiber mask material were tested and analyzed. The result showed that PVA/AgNPs composite nanofiber mask material has good filtration, moisture permeability and air permeability, and has broad application prospects.
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Huang, Yi-Jen, Chien-Lin Huang, Ruo-Yu Lai, Cheng-Han Zhuang, Wei-Hao Chiu et Kun-Mu Lee. « Microstructure and Biological Properties of Electrospun In Situ Polymerization of Polycaprolactone-Graft-Polyacrylic Acid Nanofibers and Its Composite Nanofiber Dressings ». Polymers 13, no 23 (3 décembre 2021) : 4246. http://dx.doi.org/10.3390/polym13234246.
Texte intégralRésumé :
In this study, polycaprolactone (PCL)- and poly(acrylic acid) (PAA)-based electrospun nanofibers were prepared for the carriers of antimicrobials and designed composite nanofiber mats for chronic wound care. The PCL- and PAA-based electrospun nanofibers were prepared through in situ polymerization starting from PCL and acrylic acid (AA). Different amounts of AA were introduced to improve the hydrophilicity of the PCL electrospun nanofibers. A compatibilizer and a photoinitiator were then added to the electrospinning solution to form a grafted structure composed of PCL and PAA (PCL-g-PAA). The grafted PAA was mainly located on the surface of a PCL nanofiber. The optimization of the composition of PCL, AA, compatibilizer, and photoinitiator was studied, and the PCL-g-PAA electrospun nanofibers were characterized through scanning electron microscopy and 1H-NMR spectroscopy. Results showed that the addition of AA to PCL improved the hydrophilicity of the electrospun PCL nanofibers, and a PCL/AA ratio of 80/20 presented the best composition and had smooth nanofiber morphology. Moreover, poly[2 -(tert-butylaminoethyl) methacrylate]-grafted graphene oxide nanosheets (GO-g-PTA) functioned as an antimicrobial agent and was used as filler for PCL-g-PAA nanofibers in the preparation of composite nanofiber mats, which exerted synergistic effects promoted by the antibacterial properties of GO-g-PTA and the hydrophilicity of PCL-g-PAA electrospun nanofibers. Thus, the composite nanofiber mats had antibacterial properties and absorbed body fluids in the wound healing process, thereby promoting cell proliferation. The biodegradation of the PCL-g-PAA electrospun nanofibers also demonstrated an encouraging result of three-fold weight reduction compared to the neat PCL nanofiber. Our findings may serve as guidelines for the fabrication of electrospun nanofiber composites that can be used mats for chronic wound care.
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Gao, Da Wei, Qu Fu Wei, Chun Xia Wang, Guo Liang Liu, Xue Mei He, Li Li Wang, Tian Chi Zhou, Bian Bian Yuan et Xin Zou. « Preparation and Characterization of Porous Carbon/Nickle Nanofibers by Electrospinning ». Advanced Materials Research 853 (décembre 2013) : 101–4. http://dx.doi.org/10.4028/www.scientific.net/amr.853.101.
Texte intégralRésumé :
By employing the electrospinning technique and subsequent carbonization processes, porous carbon/nickle (C/Ni) composite nanofibers with diameters of 100-200 nm were successfully prepared. Two polymer solutions of polyacrylonitrile (PAN), polyvinyl pyrrolidone (PVP), and Ni (CH3COOH)2(Ni (OAc)2) were used as C/Ni composite nanofiber precursors. The study revealed that C/Ni composite nanofibers were successfully prepared and nickle particles with diameters of 20-70 nm were uniformly scattered in the carbon nanofibers. It was also observed that the fiber with clear fibrous morphology with particles broke into shorter fibers after sinter. X-ray diffraction (XRD) showed that these particles crystallized with the face centered cubic (FCC) structure. The Brunauer-Emmett-Teller (BET) analysis indicated that C/Ni composites nanofibers with meso-pores possessed larger specific surface area than that of carbon nanofibers.
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Wei, Anfang, Juan Wang, Xueqian Wang, Dayin Hou et Qufu Wei. « Morphology and Surface Properties of Poly (L-lactic acid)/Captopril Composite Nanofiber Membranes ». Journal of Engineered Fibers and Fabrics 7, no 1 (mars 2012) : 155892501200700. http://dx.doi.org/10.1177/155892501200700115.
Texte intégralRésumé :
In this study, Poly (L-lactic acid)/Captopril composite nanofiber membranes were electrospun for drug delivery. Different mass fractions of Poly (L-lactic acid), different ratios of Captopril and the influences of PEG4000 added in the spinning solution are discussed. The morphology, chemical components, the surface areas and pore sizes, wettability of the composite nanofiber membranes were investigated. The results showed that the diameters of the composite nanofibers increased with the increase of Poly (L-lactic acid) mass fractions, the diameters decreased with the increase of Captopril content as well as the addition of the surfactant. Fourier Transform Infrared (FT-IR) showed the chemical components of Captopril remained unchanged when it was electrospun into the composite nanofibers. The surface areas pore width and pore volume of the composite nanofibers became a little larger than those of poly (L-lactic acid) nanofibers, and the wettability of the composite nanofiber membranes was better than those of poly (L-lactic acid) nanofiber membranes. Wettability was improved by an increase of the drug load amount.
Thèses sur le sujet "Composite nanofibers"
1
Bayat, Masoumeh. « Electromagnetic composite nanofibers ». Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/39894.
Texte intégralRésumé :
Multifunctional composite nanofibers containing magnetite (Fe₃O₄) nanoparticles are developed
in this work. The multifunctional composite nanofibers are proved to be electrically conductive
and magnetically permeable. Polyacrylonitrile (PAN) is used as an appropriate polymer which is
capable of being pyrolized to produce electrically conductive carbon nanofiber matrix. In order
to develop magnetic nanofibers, various amounts of Fe₃O₄ nanoparticles ranging from 3 to
10wt.% are embedded in the PAN nanofiber matrix. In addition, the electromagnetic behaviour
of nanocomposites made of two different sizes (GA:20-30nm and GB:10-20nm) of Fe₃O₄
nanoparticles is examined. Electrospun composite nanofibers are thermally treated at both 700°C
and 900°C to produce electromagnetic carbon nanofiber composites. The composite nanofibers
are characterized using scanning electron microscopy (SEM), transmission electron microscopy
(TEM), X-ray diffractometry (XRD), Raman spectroscopy, four-point probe and
Superconducting Quantum Interference Device (SQUID). Electromagnetic Interference
Shielding Effectiveness (EMI SE) of the pristine carbon nanofibers as well as electromagnetic
composite nanofibers is examined using Vector Network Analyzer with Thru-Reflect-Line
(TRL) calibration. Uniform nanofibers are obtained for all samples with choosing 10wt.% PAN
concentration in Dimethylformamide (DMF) with larger fiber diameters for composite
nanofibers as compared with pristine carbon nanofiber. The magnetic properties of Fe₃O₄
nanoparticles are successfully transferred into the as-spun Fe₃O₄/PAN composite nanofibrous
structure. The electromagnetic properties of the composite materials are tuned by adjusting the
amount and size of Fe₃O₄ nanoparticles in the matrix and carbonization process. By embedding
10wt.% of GA:20-30nm Fe₃O₄ nanoparticle, saturation magnetization (Ms) of 16emu/g is obtained with electrical conductivity of 9.2S/cm for composite nanofiber carbonized at 900°C. However, the Ms and electrical conductivity values respectively decrease to 9.0emu/g and 1.96S/cm for composite made of 10wt.% GB:10-20nm Fe₃O₄ nanoparticle carbonized at 900°C. The high surface area provided by the ultrafine fibrous structures, the flexibility and tuneable electromagnetic properties are expected to enable the expansion of the design options for a wide range of electronic devices such as sensors and actuators as well as Electromagnetic Interference Shielding Effectiveness (EMI SE). The electromagnetic composite nanofibers are demonstrated to act as strong electromagnetic interference shield of up to 70-80dB.
2
Haji, Aminoddin, Komeil Nasouri, Ahmad Mousavi Shoushtari et Ali Kaflou. « Reversible Hydrogen Storage in Electrospun Composite Nanofibers ». Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35201.
Texte intégralRésumé :
Composite nanofibers containing single-walled carbon nanotubes (SWNT) were prepared by using elec-trospinning technique and hydrogen adsorption/desorption isotherms were carried out by a Sieverts appa-ratus at room temperature. The SEM analysis of the nanofibers revealed that the deformation of the nano-fiber increases with increasing SWNT concentration. The diameter of neat nanofibers was below 200 nm and had smooth surface. The surface of the composite nanofibers was rough even by adding low quantity of SWNT. The hydrogen storage results showed an improvement in the adsorption capacity with increasing the SWNT content in composite nanofibers. These nanofibers were evacuated again to remove the ad-sorbed hydrogen at room temperature. Moreover, even though specific surface area and total pore volume were important factors for increasing the capacity of hydrogen adsorption. Finally, maximum adsorption capacity was 0.29 wt % in case of nanofibers with 10 wt % SWNT under 30 bar at 298 K.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35201
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Bovicelli, Federico. « On the influence of polymeric nanofibers in laminated composite materials. Studio dell'influenza di nanofibre polimeriche in materiali compositi laminati ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/6784/.
Texte intégralRésumé :
During the last years an increased interest about the reinforcement of laminated composites by means of polymeric nanofibers has been growth. During this master-degree-thesis work, unidirectional and plane-textile composites have been interleaved with Nylon 6.6, PCL and mixed (Nylon 6.6+PCL) nanofibrous mats and the DCB (mode I interlaminar fracture toughness), ENF (mode II interlaminar fracture toughness and DMA (damping capability) tests have been performed. Regarding the interlaminar fracture toughness, marked increases have been recorded; while further investigation about damping capability is requested.
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Almuhamed, Sliman. « Study and Development of Nonwovens made of Electrospun Composite Nanofibers ». Thesis, Mulhouse, 2015. http://www.theses.fr/2015MULH8864.
Texte intégralRésumé :
L’électrofilage est actuellement la méthode la plus utilisée pour la production de nanofibres grâce à sa simplicité, sa reproductibilité et la possibilité d’être industrialisée. Grâce à leurs propriétés particulières telles qu’un grand rapport surface-volume, une porosité inter-fibre élevée et une grande capacité d’adsorption, les nanofibres électrofilées sont de bons candidats pour de nombreuses applications telles que la filtration, les masques respiratoires, les matériaux composites, etc. Cependant, certaines applications particulières, telles que les capteurs, les systèmes d'administration contrôlée de médicaments ou les super condensateurs, exigent que les nanofibres doivent présenter des propriétés complémentaires telles que la conductivité électrique, la porosité de surface de nanofibres, l’hydrophobicité, ou d’autres propriétés particulières. Certains nanomatériaux comme les nanotubes de carbone, la silice mésoporeuse ordonnée, les argiles, ont des propriétés particulières comme la conductivité électriques élevée des nanotubes de carbone, la porosité des matériaux de silice mésoporeuse ordonnée ou de l’argile. Ces propriétés des nanomatériaux peuvent être les fonctions complémentaires cherchées. Dans notre étude, des non-tissés composés de nanofibres de polyacrylonitrile chargées par nanotubes de carbone à multi-parois (MWNT), de la montmorillonite sodique (MMT-Na) ou de la silice mésoporeuse ordonnée (de type SBA-15), sont produits par électrofilage. Les résultats montrent que l’insertion de MWNT rend le non-tissé conducteur en augmentant la conductivité électrique volumique par six ordres de grandeur (de ~ 2×10-12 à ~ 3×10-6 S/m) avec un très faible seuil de percolation de 0.5 % massique. Lorsque le non-tissé est soumis à une compression, la conductivité électrique volumique augmente en augmentant la pression (jusqu’à ~ 2 kPa). Ces non-tissés conducteurs sont très intéressants pour le développement des capteurs à faible amplitude. Les résultats montrent aussi que l’accessibilité des pores des particules inorganiques (c’est-à-dire, les mésopores de SBA-15 et l’espace interfoliaire de MMT-Na) insérées dans la structure nano fibreuse est encore possible. Il a été trouvé que plus de 50% des mésopores de SBA-15 insérées sont encore accessibles quelles que soit les conditions de l’électrofilage et la fraction massique de SBA-15. En outre, l’insertion de ces particules inorganiques apporte plus de stabilité thermique aux nanofibres compositesElectrospinning is the most common method for the production of nanofibres due to its simplicity, repeatability, and the ability to be scaled up. Owing to their advanced properties like the high surface-to-volume ratio, high interfibrous porosity, high adsorption capacity, etc. electrospun nanofibers are good candidates for many applications such as filtration, respiratory masks, composite materials and others. However, some specific applications including sensors, controlled drug delivery systems, supercapacitors, etc. still require complimentary functions that do not exist in pristine nanofibers in their basic structure like the electrical conductivity, surface porosity of the nanofibers, hydrophobicity, and others.Nanomaterials like carbon nanotubes, ordered mesoporous silica, layered silicate, etc. are characterized by particular properties like the high electrical conductivity of carbon nanotubes, the porosity of ordered mesoporous silica or layered silicate. These particular properties of nanomaterials can fulfill of the targeted functions.In our study, nonwovens made from nanofibers of polyacrylonitrile incorporated with multiwalled carbon nanotubes (MWNT), layered silicate type Na-montmorillonite (Na-MMT) or ordered mesoporous silica type SBA-15 are successfully produced by electrospinning.Results reveal that the incorporation of MWNT altered the electrical state of the nonwoven from insolent to conductor where the volume electrical conductivity increased by six order of magnitude (from ~ 2×10-12 to ~ 3×10-6 S/m) with a very low percolation threshold of about 0.5 wt%. The application of mechanical pressure to the conductive nonwoven causes an increase in the volume electrical conductivity with the increase of the applied pressure (up to ~ 2 kPa). Such conductive nonwoven is very interesting for the development of sensor with low amplitude.Results also show that accessibility of the pores of the inorganic particles (i.e. mesopores of SBA-15 and interlayer space of Na-MMT) incorporated into the nanofibers is still possible. It is found that at least 50% of SBA-15 mesopores are still accessible whatever is the electrospinning conditions and SBA-15 mass fraction. In addition, the incorporation of the studied inorganic particles yields higher thermal stability for the composite nanofibers
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Antoine, Donley. « Optical Transparent Pmma Composite Reinforced By Coaxial Electrospun Pan Hollow Nanofibers ». Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc271772/.
Texte intégralRésumé :
Electrospinning has been recognized as an efficient technique for the fabrication of polymer fibers. These electrospun fibers have many applications across a broad range of industries. In this research, optical transparent composites were successfully fabricated by embedding polyacrylonitrile (PAN) hollow nanofibers into poly (methyl methacrylate) (PMMA) matrix. The hollow PAN nanofibers were prepared by coaxial electrospinning. The PAN was used as the shell solution, and the mineral oil was used as the core solution. The resulting fibers were then etched with octane to remove the mineral oil from the core. The hollow PAN fibers were then homogeneously distributed in PMMA resins to fabricate the composite. The morphology, transmittance and mechanical properties of the PAN/PMMA composite were then characterized with an ESEM, TEM, tensile testing machine, UV-vis spectrometer and KD2 Pro Decagon device. The results indicated that the hollow nanofibers have relatively uniform size with one-dimensional texture at the walls. The embedded PAN hollow nanofibers significantly enhanced the tensile stress and the Young's modulus of the composite (increased by 58.3% and 50.4%, respectively), while having little influence on the light transmittance of the composite. The KD2 Pro device indicated that the thermal conductivity of the PMMA was marginally greater than the PAN/PMMA composite by 2%. This novel transparent composite could be used for transparent armor protection, window panes in vehicles and buildings, and airplane windshield etc.
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Vidotti, Hugo Alberto. « O papel da concentração de nanofibras e da composição da matriz resinosa nas propriedades flexurais de compósitos experimentais baseados em nanofibras ». Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/25/25146/tde-26042016-104952/.
Texte intégralRésumé :
O objetivo do presente estudo foi de avaliar a influência de soluções de resina com diferentes proporções de monômeros e diferentes concentrações em massa de nanofibras nas propriedades flexurais de compósitos resinosos experimentais reforçados com nanofibras de poliacrilonitrila (PAN). Materiais e métodos: Nanofibras de PAN foram produzidas pelo processo de eletrofiação e caraterizadas por teste de tração e microscopia eletrônica de varredura (MEV). Os compósitos experimentais foram produzidos pela infiltração das mantas de nanofibras com diferentes misturas de BisGMA-TEGDMA (BisGMA/TEGDMA: proporções em % massa de 30/70, 50/50, e 70/30). Foram incorporadas diferentes concentrações em massa de nanofibras (de 0% a 8%). Espécimes em forma de barra foram seccionados a partir de blocos do compósito experimental e armazenados em água na temperatura de 37oC por 24h anteriormente à realização dos testes de flexão de três pontos. Foram avaliados a resistência flexural (RF), o módulo flexural (MF) e o trabalho de fratura (TF). Resultados: Os testes de tração das nanofibras de PAN demonstraram um comportamento anisotrópico das mantas de nanofibras. As propriedades mecânicas exibiram maiores valores na direção perpendicular ao eixo de rotação do coletor metálico utilizado na produção das fibras por eletrofiação. Maiores proporções de BisGMA nas misturas de resina resultaram em maiores valores de RF e MF, o que não ocorreu para os valores de TF. A adição de diferentes concentrações de nanofibras não afetou as propriedades de RF e MF em comparação com o grupo controle (resina pura) (p>0.05). No entanto, a adição das nanofibras promoveu um aumento significante do TF, principalmente para as misturas de resina com maior proporção de TEGDMA (p<0,05). Significância: A inclusão de nanofibras de PAN em resinas de modo a formar compósitos resinosos reforçados por nanofibras não afetou negativamente as propriedades flexurais do material e resultou em um aumento significativo da tenacidade, uma propriedade desejável para um material a ser utilizado para aplicação restauradora.The present study had the objectives to evaluate the influence of different resin blends concentrations and nanofibers mass ratio on flexural properties of experimental Poliacrylonitrile (PAN) nanofibers reinforced composite. Materials and Methods: Poliacrylonitrile (PAN) nanofibers mats were produced by electrospinning and characterized by tensile testing and scanning electron microscopy (SEM). Experimental resin-fiber composite beams were manufactured by infiltrating PAN nanofiber meshs with varied concentrations of BisGMA-TEGDMA resin blends (BisGMA/TEGDMA: 30/70, 50/50 and 70/30 weight %). The mass ratio of fiber to resin varied from 0% to 8%. Beams were cured and stored in water at 37oC. Flexural strength (FS), flexural modulus (FM) and work of fracture (WF) were evaluated by three-point bending test after 24 hs storage. Results: The tensile properties of the PAN nanofibers indicated an anisotropic behavior being always higher when tested in a direction perpendicular to the rotation of the collector drum. Except for WF, the other flexural properties (FS and FM) were always higher as the ratio of BisGMA to TEGDMA increased in the neat resin beams. The addition of different ratios of PAN fibers did not affect FS and FM of the composite beams as compared to neat resin beams (p>0.05). However, the addition of fibers significantly increased the WF of the composite beams, and this was more evident for the blends with higher TEGDMA ratios (p<0.05). Significance: The inclusion of PAN nanofibers into resin blends did not negatively affect the properties of the composite and resulted in an increase in toughness that is a desirable property for a candidate material for restorative application.
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Yang, Xiaojiao. « Synthesis and Characterization of Hybrid Metal-Metallic Oxide Composite Nanofibers by Electrospinning and Their Applications ». Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1022/document.
Texte intégralRésumé :
Nous présentons dans ce manuscrit l'élaboration par électrofilage (ES) de nanofibres hybrides métal/oxyde métallique (HMMOC) et leurs caractérisations physico-chimiques. Leurs utilisations dans le cadre d’applications de type « énergie » et « environnement » ont été évaluées. En particulier, la photocatalyse de nanofibres TiO2-Au pour la dégradation en solution aqueuse du bleu de méthylène et l’utilisation de nanofibres WO3-Au comme capteurs de gaz (VOCs) ont été examinées. En lien étroit avec les résultats obtenus sur l'évaluation des performances comme photocatalyseurs ou capteurs à gaz de ces nouvelles structures HMMOC, l'influence de nombreux paramètres a été étudiée : la concentration en ions aurique, la méthode utilisée pour introduire ces derniers à l’intérieur ou les déposer à la surface des nanofibres d’oxydes et finalement le traitement thermique. En effet, on peut soit mélanger directement, avant la procédure d’électrofilage, la solution contenant les ions aurique à la solution polymérique (composée de PVP, PAN, ou PVA contenant le précurseur d'oxyde métallique), soit déposer sous forme de goutte cette solution d’ions Au à la surface des nanofibres d’oxyde métallique une fois la procédure d’électrofilage effectuée. Quant au traitement thermique, il joue un rôle multiple puisqu’il permet à la fois, d’éliminer les composés organiques des solutions polymériques, participant ainsi à la structuration de la partie oxyde du HMMOC, mais aussi de réduire les ions Au sous forme de nanoparticules.Des résultats prometteurs en photocatalyse ont été obtenus sur des fibres optimisées de TiO2 contenant des nanoparticules d’Au de 10 nm (concentration en Au : 4 wt%). En effet, pour cet échantillon, on montre une dégradation 3 fois plus rapide du bleu de méthylène en solution aqueuse que celle obtenue sur les nanofibres de TiO2 de références et sur le catalyseur commercial P25. De la même manière, des nanofibres de WO3 décorées de nanoparticules d’Au de 10 nm, utilisées comme capteurs de gaz, permettent d’obtenir une réponse 60 fois plus importante que dans le cas de nanofibres de WO3 pure et en améliorant grandement la sélectivité par rapport au n-butanolWe present in this manuscript the elaboration by Electrospinning (ES) process of hybrid metal-metallic oxide composite (HMMOC) nanofibers (NFs), and their physical-chemical characterizations. Their applications, especially the photocatalysis of TiO2-Au composite NFs for photocatalytic degradation for methylene blue (MB) in an aqueous solution and WO3-Au composite NFs for gas sensing of the volatile organic compounds (VOCs) have been investigated. According to the performance evaluation results as photocatalyst or gas sensors, the influence of many parameters have been studied: gold ions concentration, the way to introduce them into or at the NFs surface, typically by mixing them into the polymeric solution (composed of PVP, PAN, or PVA with the metallic oxide precursor) before the ES process or by simple droplet deposition onto the NFs after ES process, and finally the annealing treatment. This latter plays an important role since it both removes the organic components of the polymeric solution, thus forming the metal oxide and in-situ participates to the Au reduction.Concerning the photocatalytic properties, an optimized HMMOC material based on TiO2 NFs including 10 nm Au nanoparticles (NPs) has been obtained and shows 3 times significantly improvement of MB degradation compared to pure TiO2 NFs and the commercial catalyst P25. For gas sensing elaboration, we have shown that a HMMOC material based on WO3 NFs decorated at their surface with 10 nm Au NPs can exhibit 60 times higher response and significantly improved selectivity toward n-butanol compared with pure WO3 NFs
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Roman, Julien. « Mise en forme de matériaux carbonés biosourcés par voie liquide ». Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0202/document.
Texte intégralRésumé :
Ce travail de thèse est consacré à la mise en forme de nouveaux matériaux carbonés à partir d’un précurseur biosourcé. Les matériaux carbonés tels que les fibres de carbone utilisés dans les composites sont principalement obtenus à partir de précurseurs d’origine pétrosourcée. Ces précurseurs sont onéreux et incompatibles avec une industrie durable. L’utilisation d’un précurseur biosourcé disponible en grande quantité tel que la lignine permet de pallier ces limitations. La structure moléculaire aromatique et la teneur élevée en carbone de la lignine font d’elle un candidat idéal pour l’élaboration de matériau carboné biosourcé. La lignine a pu être transformée en divers matériaux carbonés tels que des nanofibres de carbone, des tresses de nanofibres de carbone, ou encore des objets 3D composites carbonisés. Ces matériaux ont été obtenus à partir de techniques innovantes que sont l’électrofilage et l’impression 3D. Le tressage des nanofibres de carbone ex-lignine a permis d’évaluer les propriétés mécaniques des fibres de carbone. Les propriétés électrochimiques des tresses de nanofibres de carbone ex-lignine sont apparues intéressantes pour une utilisation potentielle en tant que microélectrodes. La microstructure faiblement organisée du carbone issue de la lignine a pu être améliorée. Un traitement thermique de graphitisation ou un ajout de nanocharges carbonées ont contribué à cette amélioration. Les propriétés mécaniques, structurales et de conductivité électrique des nanofibres nanocomposites ont permis de définir l’influence de l’oxyde de graphène sur la lignine. Un effet composite entre ces deux constituants a pu être observé. L’impression 3D d’encres composites à base de lignine et d’oxyde de graphène a pu être rapportée pour la première fois afin d’élaborer des objets 3D carbonisés denses, organisés et conducteurs d’électricitéThis work is devoted to the preparation of new bio-based carbon materials. Carbon materials, such as carbon fibers used in composites, are mainly obtained from a petroleum precursor. These precursors are expensive and not compatible with a sustainable industry. The use of a bio-based precursor available in large quantities such as lignin makes it possible to overcome limitations of petroleum based precursors. The aromatic molecular structure and high carbon content of lignin make it an ideal candidate for the production of bio-based carbon material. Lignin could be transformed into various materials such as carbon nanofibers, twisted carbon nanofibers, or carbonized composite 3D structures. These materials have been obtained from innovative techniques such as electrospinning and 3D printing. Twisting of the lignin-based-carbon nanofibers allowed for measurements of their mechanical strength. The electrochemical properties of the lignin-based twisted carbon nanofibers are interesting for potential microelectrode applications. The low microstructural order of the carbon from the carbonized lignin has been improved. Graphitization treatment or addition of carbon nanofillers contributed to this improvement. The mechanical, structural and electrical properties of nanocomposite carbon nanofibers illustrate the influence of graphene oxide on lignin. A composite effect between these two components has been observed. The 3D printing of composite inks based on lignin and graphene oxide has been reported for the first time in order to elaborate dense, organized and electrically conductive 3D carbonized structures
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Vincent, Cécile. « Le composite cuivre / nanofibres de carbone ». Phd thesis, Université Sciences et Technologies - Bordeaux I, 2008. http://tel.archives-ouvertes.fr/tel-00377607.
Texte intégralRésumé :
Le matériau composite Cu/NFC (Nano Fibre de Carbone) peut être utilisé en tant que drain thermique par les industriels de l'électronique de puissance. En remplacement du cuivre, il doit combiner une conductivité thermique élevée et un coefficient de dilatation thermique adapté à celui de la céramique du circuit imprimé (alumine ou nitrure d'aluminium). Après avoir étudié les propriétés de la matrice cuivre et des NFC, plusieurs méthodes de synthèse du composite Cu/NFC ont été développées. Le composite a tout d'abord été élaboré par métallurgie des poudres. Puis, dans le but d'améliorer l'homogénéité, il a été envisagé de revêtir individuellement chaque NFC par du cuivre déposé par voie chimique electroless ainsi que par une méthode originale de décomposition d'un sel métallique. Des mesures de densité et de propriétés thermiques (conductivité et dilatation) ainsi que les caractérisations microstructurales de ces matériaux montrent la complexité de l'élaboration d'un tel composite. En effet, la dispersion des nanofibres, la nature des interfaces fibres/matrice et surtout les phénomènes thermiques à l'échelle nanométrique sont autant de paramètres à contrôler afin d'obtenir les propriétés recherchées. La simulation numérique et analytique, qui a été mise en oeuvre en parallèle a été corrélée aux résultats expérimentaux, afin de prédire les propriétés finales de nos matériaux.
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Klose, Carolin, Matthias Breitwieser, Severin Vierrath, Matthias Klingele, Hyeongrae Cho, Andreas Büchler, Jochen Kerres et Simon Thiele. « Electrospun sulfonated poly(ether ketone) nanofibers as proton conductive reinforcement for durable Nafion composite membranes ». Elsevier, 2017. https://publish.fid-move.qucosa.de/id/qucosa%3A72523.
Texte intégralRésumé :
We show that the combination of direct membrane deposition with proton conductive nanofiber reinforcement yields highly durable and high power density fuel cells. Sulfonated poly(ether ketone) (SPEK) was directly electrospun onto gas diffusion electrodes and then filled with Nafion by inkjet-printing resulting in a 12 μm thin membrane. The ionic membrane resistance (30 mΩ*cm2) was well below that of a directly deposited membrane reinforced with chemically inert (PVDF-HFP) nanofibers (47 mΩ*cm2) of comparable thickness. The power density of the fuel cell with SPEK reinforced membrane (2.04 W/cm2) is 30% higher than that of the PVDF-HFP reinforced reference sample (1.57 W/cm2). During humidity cycling and open circuit voltage (OCV) hold, the SPEK reinforced Nafion membrane showed no measurable degradation in terms of H2 crossover current density, thus fulfilling the target of 2 mA/cm2 of the DOE after degradation. The chemical accelerated stress test (100 h OCV hold at 90 °C, 30% RH, H2/air, 50/50 kPa) revealed a degradation rate of about 0.8 mV/h for the fuel cell with SPEK reinforced membrane, compared to 1.0 mV/h for the PVDF-HFP reinforced membrane.
Livres sur le sujet "Composite nanofibers"
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Poveda, Ronald L., et Nikhil Gupta. Carbon Nanofiber Reinforced Polymer Composites. Cham : Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-23787-9.
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Kim, Ick-Soo, Sana Ullah et Motahira Hashmi, dir. Electrospun Composite Nanofibers for Functional Applications. MDPI, 2022. http://dx.doi.org/10.3390/books978-3-0365-4523-3.
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Ko, Frank K., et Yuqin Wan. Introduction to Nanofiber Materials. Cambridge University Press, 2014.
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Ko, Frank K., et Yuqin Wan. Introduction to Nanofiber Materials. Cambridge University Press, 2014.
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Introduction to Nanofiber Materials. Cambridge University Press, 2014.
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Engineered Carbon Nanotubes and Nanofibrous Material. Taylor & Francis Group, 2018.
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Thomas, Sabu, A. K. Haghi et Praveen K. M. Engineered Carbon Nanotubes and Nanofibrous Material. Taylor & Francis Group, 2021.
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Thomas, Sabu, A. K. Haghi et Praveen K. M. Engineered Carbon Nanotubes and Nanofibrous Material : Integrating Theory and Technique. Apple Academic Press, Incorporated, 2018.
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Chung, Deborah D. L. Carbon Composites : Composites with Carbon Fibers, Nanofibers and Nanotubes. Elsevier Science & Technology Books, 2016.
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Calvert, Paul, et Roger Narayan. Nanofiber Composites : Fundamentals and Developments. Wiley & Sons, Incorporated, John, 2012.
Trouver le texte intégralChapitres de livres sur le sujet "Composite nanofibers"
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Molnár, K., et L. M. Vas. « Electrospun Composite Nanofibers and Polymer Composites ». Dans Synthetic Polymer-Polymer Composites, 301–49. München : Carl Hanser Verlag GmbH & ; Co. KG, 2012. http://dx.doi.org/10.3139/9781569905258.010.
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Abdul Khalil, H. P. S., Y. Davoudpour, A. H. Bhat, Enih Rosamah et Paridah Md Tahir. « Electrospun Cellulose Composite Nanofibers ». Dans Handbook of Polymer Nanocomposites. Processing, Performance and Application, 191–227. Berlin, Heidelberg : Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-45232-1_61.
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Han, X. J., Z. M. Huang, L. Liu, C. L. He, Q. S. Wu et Y. Li. « Composite Nanofibers for Textile Applications ». Dans Solid State Phenomena, 1237–40. Stafa : Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/3-908451-30-2.1237.
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Bharti, Pradeep Kumar et Pramod Kumar Rai. « Functionalized Carbon Nanotubes-Based Electrospun Nano-Fiber Composite and Its Applications for Environmental Remediation ». Dans Electrospun Nanofibers, 353–76. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-79979-3_13.
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Naraghi, Mohammad, et Ioannis Chasiotis. « Mechanics of PAN Nanofibers ». Dans Major Accomplishments in Composite Materials and Sandwich Structures, 757–78. Dordrecht : Springer Netherlands, 2009. http://dx.doi.org/10.1007/978-90-481-3141-9_28.
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Jayakumar, R., M. Prabaharan, K. T. Shalumon, K. P. Chennazhi et S. V. Nair. « Biomedical Applications of Polymer/Silver Composite Nanofibers ». Dans Biomedical Applications of Polymeric Nanofibers, 263–82. Berlin, Heidelberg : Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/12_2011_123.
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Dror, Yael, Wael Salalha, Wim Pyckhout-Hintzen, Alexander L. Yarin, Eyal Zussman et Yachin Cohen. « From carbon nanotube dispersion to composite nanofibers ». Dans Scattering Methods and the Properties of Polymer Materials, 64–69. Berlin, Heidelberg : Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/b107346.
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Takagi, Hitoshi, et Akira Asano. « Characterization of “Green” Composites Reinforced by Cellulose Nanofibers ». Dans Advances in Composite Materials and Structures, 389–92. Stafa : Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-427-8.389.
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Correa, Daniel S., Luiza A. Mercante, Rodrigo Schneider, Murilo H. M. Facure et Danilo A. Locilento. « Composite Nanofibers for Removing Water Pollutants : Fabrication Techniques ». Dans Handbook of Ecomaterials, 1–29. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-48281-1_172-1.
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Polini, Alessandro, Silvia Scaglione, Rodolfo Quarto et Dario Pisignano. « Composite Electrospun Nanofibers for Influencing Stem Cell Fate ». Dans Methods in Molecular Biology, 25–40. Totowa, NJ : Humana Press, 2012. http://dx.doi.org/10.1007/7651_2012_4.
Texte intégralActes de conférences sur le sujet "Composite nanofibers"
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Plaseied, Atousa, et Ali Fatemi. « Mechanical Properties and Deformation Behavior of a Carbon Nanofiber Polymer Composite Material ». Dans ASME 2006 Multifunctional Nanocomposites International Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/mn2006-17043.
Texte intégralRésumé :
Tensile behavior of a carbon nanofiber reinforced vinyl ester polymer composite was studied using dog-bone shaped specimens to obtain its mechanical properties. Pyrograf III which is a very fine, highly graphitic and yet low cost carbon nanofiber was used as the fiber material. Vinyl ester with low molecular weight which was used as the matrix material is a thermoset with high tensile strength at room temperature. When small amounts of carbon nanofibers are combined with vinyl ester, the stiffness of the resulting composite can improve if the fiber-matrix adhesion is good. The mechanical properties can improve further after surface treatment (functionalization) of carbon nanofibers. This surface treatment adds some functional groups chemically to the nanofiber’s surface which increases the adhesion between nanofiber and matrix resin. Understanding the mechanical behavior of these composites is crucial to their effective application. In this research the stiffness, strength, and tensile deformation behavior of these nanocomposites were investigated. The effects of matrix curing systems and composition, strain rate, nanofiber concentration, nanofiber surface treatment and environment such as low and high temperatures and humidity were also characterized. Based on the mechanical properties simple models were used to represent tensile stress-strain and deformation behaviors of the nanocomposite. The experimental results were also applied to these models to examine their predictive capability.
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Rijal, Nava P., Udhab Adhikari et Narayan Bhattarai. « Magnesium Incorporated Polycaprolactone-Based Composite Nanofibers ». Dans ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-53090.
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Recent advances in developing composite nanofibers are of great interest for scientific community due to their wide range of potential applications in biomedical engineering such as drug delivery, wound healing, tissue engineering and implant coatings. Here, we present a fabrication of Mg incorporated polycaprolactone/low molecular weight chitosan (PCL/LMW-CS) composite nanofiber via an electrospinning technique. PCL, a synthetic polymer, has good mechanical properties, whereas, chitosan, a natural polymer, has good bio-functional properties and good cell adhesion properties. Furthermore, magnesium is the second most abundant intracellular cation in the body and is important to metabolism. These nanofibers were characterized by using Scanning Electron Microscopy (SEM), ImageJ, and Instron Universal Testing Machine.
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Gou, J., S. Sumerlin, H. C. Gu et G. Song. « Damping Enhancement of Hybrid Nanocomposites Embedded With Engineered Carbon Nanopaper ». Dans ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-15749.
Texte intégralRésumé :
This paper presents a novel process to manufacture multifunctional and cost-effective hybrid nanocomposites through integrating engineered carbon nanofiber paper into traditional fiber reinforced composites to improve structural damping properties. In this study, carbon nanofibers are vapor grown carbon fibers, which are grown catalytically from gaseous hydrocarbons using metallic catalyst particles. Vapor grown carbon nanofibers are much less costly than single-walled and multi-walled carbon nanotubes. Carbon nanofibers were preformed as a nanopaper which had a porous structure with highly entangled carbon nanofibers and short glass fibers. The vacuum-assisted resin transfer molding (VARTM) process was used to fabricate the nanocomposites by using engineered carbon nanofiber paper as inter-layer or surface layer of traditional composite laminates. To characterize the structural damping properties, the influence of frequency dependence was analyzed through the experiments conducted using the nanocomposite beams. It was found that there is up to 200-700% increase of the damping ratios at higher frequencies. In addition, experiments were also performed to study the interface characteristics between the carbon nanofiber paper and the laminate ply. The study showed a complete penetration of the resin through the carbon nanofiber paper. It was found that the connectivities between carbon nanofibers and short glass fibers within the carbon nanofiber paper were responsible for the significant energy dissipation in the hybrid nanocomposites during the structural vibration applications. The research results confirm the possible advantage of using engineered carbon nanofiber for damping augmentation.
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Rohatgi, A., J. N. Baucom, W. R. Pogue et J. P. Thomas. « Microstructure-Property Relation in a Liquid Crystalline Polymer-Carbon Nanofiber Composite ». Dans ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80045.
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Microstructure-property relationship is being examined in a polymer matrix composite system consisting of vapor grown carbon nanofibers (VGCF) mixed in a thermotropic liquid crystalline polymer (LCP) matrix. These nanocomposites show an inherent hierarchical structuring, which we hope to utilize in the development of multifunctional structure-conduction composites with improved performance. Among unfilled polymers, extruded LCPs show relatively high strength and high stiffness that have been attributed in the literature to the preferential molecular alignment along the extrusion direction and the hierarchical nature of LCPs. Further, as is typical for polymers, LCPs have poor thermal and electrical conductivity relative to metals. By contrast, carbon nanofibers are known to possess high strength, high stiffness and high conductivity in the axial direction. It is expected that the combination of the extrusion process and the similarity of the length-scales of LCP fibrils and carbon nanofibers will lead to improved axial alignment of both phases within the nanocomposite filaments. This simultaneous alignment of the LCP matrix and that of the carbon nanofibers is expected to lead to interesting mechanical and conductive behavior in the nanocomposite filaments through hierarchical interactions at the nanometer to micrometer scale levels. Carbon nanofibers, 60-150 nm in diameter, were mixed with Vectra A950 LCP and the mixture was extruded as 0.5–2 mm diameter filaments. Nanocomposite filaments with 1%, 2%, 5% and 10 wt.% VGCF were characterized via tensile testing and fractography. The tensile modulus, failure strength and strain-to-failure were found to be sensitive to filament diameter, carbon nanofiber content and extrusion process. There was a noticeable increase in mechanical performance with decreasing filament diameter irrespective of carbon nanofiber content. Fracture surfaces showed hierarchical features from nanometer to micrometer scale and processing defects in the form of voids. The results of this research will be used to fabricate composite components that exploit structural hierarchy from nano-to macro-scale.
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Kimbro, Evan, et Ajit D. Kelkar. « Development of Energy Absorbing Laminated Fiberglass Composites Using Electrospun Glass Nanofibers ». Dans ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64746.
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Failure due to delamination of composite laminates via low velocity impact damages is critical because of the subsurface nature of delamination. Traditional methods such as stitching and Z-pinning, while improving interlaminar properties in woven composites, lead to a reduction of the in-plane properties. Electrospun non-woven sheets of nanofibrous mat applied at interfacial regions offer an option to traditional treatments. The objective of the present study is to observe the energy absorption during the event of an impact upon a composite laminate. The use of Tetra Ethyl Orthosilicate (TEOS) chemically engineered glass nanofibers manufactured using electrospinning technique in woven glass fiber resin pre-impregnated composite laminates were investigated for their potential to improve the interlaminar properties. Electrospun glass nanofibers pre-impregnated woven mats were manufactured using a vacuum bag and cured in a computer controlled convection oven. The interlaminar properties of the nano engineered hybrid composites were obtained using low velocity impact tests and are compared with those without the presence of electrospun nanofiber layers, to study their influence. Impacted specimens were examined using C-scan analysis to detect impact damage dimensions. It was observed when electrospinning nanofibers were added to lamina interfaces, the electrospun fiber embedded coupons had larger impact damage area compared to the coupons without electrospun fiber layers.
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Gou, Jihua, Haichang Gu et Gangbing Song. « Structural Damping Enhancement of Nanocomposites With Engineered Vapor Grown Carbon Nanofiber Paper ». Dans ASME 2006 Multifunctional Nanocomposites International Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/mn2006-17044.
Texte intégralRésumé :
Due to their nanometer size and low density, the surface area to mass ratio of carbon nanotubes and carbon nanofibers is extremely large. In addition, the large aspect ratio and high elastic modulus of carbon nanotubes and carbon nanofibers allow for large differences in strain between the constituents in the nanocomposites, which could enhance the interfacial energy dissipation ability. While there are many reported benefits of carbon nanotubes and carbon nanofibers in the nanocomposites, the potential of carbon nanotubes and carbon nanofibers to enhance the structural damping properties of nanocomposites has not been fully explored. This paper presents a novel process to manufacture multifunctional and cost-effective hybrid nanocomposites through integrating engineered carbon nanofiber paper into traditional fiber reinforced composites to improve the structural damping properties. The vacuum-assisted resin transfer molding (VARTM) process was employed to fabricate the nanocomposites by using engineered carbon nanofiber papers as inter-layers or surface layers of traditional composite laminates. To characterize the structural damping properties, the influence of frequency dependence was analyzed through the experiments conducted using the nanocomposite beams. It was found that there is up to 200–700% increase of the damping ratios at higher frequencies. It was found that the connectivities between carbon nanofibers and short glass fibers within the carbon nanofiber paper were responsible for the significant energy dissipation in the nanocomposites during structural vibration applications.
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BHAGANAGAR, SIDDHARTH, PIAS KUMAR BISWAS, MANGILAL AGARWAL et HAMID DALIR. « CELLULOSE NANOFIBERS (CNF) REINFORCED CARBON FIBER/EPOXY MATRIX COMPOSITE WITH HIGHER MECHANICAL PROPERTIES ». Dans Proceedings for the American Society for Composites-Thirty Seventh Technical Conference. Destech Publications, Inc., 2022. http://dx.doi.org/10.12783/asc37/36405.
Texte intégralRésumé :
The effect of the Cellulose Nanofibers (CNF) compositions, their morphology on carbon fiber, and subsequent mechanical properties have been explored in this work. The CNF composite nanofiber networks were introduced as interleave layers to improve the interlaminar shear strength (ILSS) of an epoxy/carbon fiber laminate composite. Dry carbon fiber was coated by different volume fractions of CNF (0.6wt%, 0.8wt%, 1wt%) through the sonication process. The CNFs volume fraction and delamination properties of enhanced carbon fiber reinforced polymer (CFRP) laminates have been studied. It is shown that when the dry carbon fiber was treated with CNF, the laminate shows greater mechanical strength in certain cases. The application of CNF composite nanofiber networks as an interleaved layer in an epoxy/carbon laminate increased the delamination resistance of the ILSS in both 0.8wt% and 1wt% CNF by 27.2% and 12.4% respectively, while compared to the neat control sample. This result suggests that CNF could enhance the delamination resistance of an epoxy/carbon laminate undergoing stress and deformation. This result is attributed to crack path modification, and load energy absorption by higher modulus CNFs reinforced nanofibers interleave in the laminate resulting in a higher shear modulus to the networks.
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Gou, J., H. C. Gu et G. Song. « Carbon Nanopaper Sheets for Damping Applications : Processing and Characterization ». Dans ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-41914.
Texte intégralRésumé :
Carbon nanotubes and carbon nanofibers have been used as nanofillers for high performance damping composite materials in recent years. The large specific area (1000 m2/g) and aspect ratio (>1000) of carbon nanotubes and nanofibers promote significant interfacial friction between carbon nanotubes/nanofibers and the polymer matrix. The high stiffness and strength of carbon nanotubes and nanofibers enlarge the differences in the strains of individual constituents of the composites, which causes much higher energy dissipation in the polymer matrix. However, adding small amount of carbon nanotubes and nanofibers will significant increase the viscosity of polymer resin, which makes the dispersion and resin flow through the porous fiber mats extremely difficult. In addition, the fiber mats will filter carbon nanotubes and nanofibers during liquid molding process such as Resin Transfer Molding (RTM) and Vacuum-Assisted Resin Transfer Molding (VARTM). A unique concept of manufacturing nanocomposites with carbon nanotube/nanofiber based nanopaper sheets for structural damping applications has recently been explored. This approach involves making carbon nanopaper sheet by the filtration of well-dispersed carbon nanotubes and carbon nanofibers under controlled processing conditions. Subsequently, carbon nanopaper sheets are integrated into composite laminates using Vacuum Assisted Resin Transfer Molding (VARTM) process. In this study, several nanocomposite plates were fabricated with carbon nanopaper sheet as surface layer. For the comparative study, the regular composite plates without carbon nanopaper sheet were also fabricated. To identify the damping characteristics of each specimen, the Frequency Response Function (FRF) was estimated by a pair of piezoceramic patches: one as an actuator to excite the specimen and the other as a sensor to detect the induced vibrations. From the FRF, the damping ratio of the specimen at each modal frequency of interests was calculated. The experimental results clearly show a significant improvement of damping properties of nanocomposites plates. This research demonstrates structural damping enhancement via carbon nanopaper sheets and provided basic understanding of the damping characteristics for the optimal design and fabrication of high performance damping composites, which have the potential to be used as structural components for many applications.
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Rohatgi, Aashish, William R. Pogue, Jared N. Baucom et James P. Thomas. « Microstructural and Mechanical Characterization of Carbon Nanofiber Reinforced Composites ». Dans ASME 2006 Multifunctional Nanocomposites International Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/mn2006-17038.
Texte intégralRésumé :
Carbon nanofibers, such as single walled carbon nanotubes (SWNT), multiwalled carbon nanotubes (MWNT) and vapor-grown carbon nanofibers (VGCF or VGCNF) are routinely compounded with polymers to create thermally and electrically conductive polymer nanocomposites. Our group is interested in combining the conduction with structural functionality by reinforcing a high-performance thermotropic liquid crystal polymer (LCP) matrix with vapor-grown carbon nanofibers and single walled carbon nanotubes. High strength and stiffness can be achieved in LCPs through the alignment of molecular domains during high-shear mixing and extrusion. Further strength and stiffness enhancements are potentially possible if the carbon nanofibers could also be aligned, perhaps, with the assistance of the aligned domains of the LCP matrix. However, the geometrical structure of VGCF is quite different and the diameter is one to two orders of magnitude larger than that of SWNT. Therefore, the processing conditions and the interactions between the LCP domains and the nanofibers are expected to lead to different dispersion and alignment characteristics of VGCF and SWNT within the LCP matrix. In this work, twin-screw and Maxwell-type mixer-extruders were used to produce neat LCP filaments and LCP-nanofiber composite filaments with various concentrations of VGCF and SWNT. The dispersion and orientation of the VGCF and SWNT reinforcements were determined by X-ray diffraction and electron microscopy. The filaments were loaded in quasi-static uniaxial tension until fracture to determine the tensile modulus, strength and strain-to-failure. The mechanical properties showed a strong dependence on the filament diameter, nanofiber concentration and processing parameters. A significant increase in mechanical performance was observed with decreasing filament diameter irrespective of the carbon nanofiber concentration. Fracture surfaces examined under electron microscopy revealed hierarchical features at multiple length scales. At the macroscopic scale, a skin-core configuration was observed in the filament cross-section with the skin possessing a greater degree of LCP molecular alignment and nanofiber alignment than the core. The mechanical and electrical properties of the LCP, LCP-VGCF and LCP-SWNT nanocomposite filaments will be described and related to processing parameters, the type of carbon nanofibers (VGCF or SWNT) and the resulting composite microstructure.
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Rasel, Abu, Evan Kimbro, Ram Mohan et Ajit D. Kelar. « Computational and Experimental Investigation of the Low Velocity Impact Behavior of Nano Engineered E-Glass Fiber Reinforced Composite Laminates ». Dans ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-86923.
Texte intégralRésumé :
This paper presents computational and experimental investigation of the low velocity impact behavior of nano engineered E-glass fiber reinforced composite laminates. The Tetra Ethyl Orthosilicate (TEOS) chemically engineered glass nanofibers were manufactured using electrospinning technique and were investigated for their potential to improve the interlaminar properties. Plain weave fiberglass prepregs were used for manufacturing ten ply thick laminates. For production of the laminates with electrospinning interface layers the addition of the electrospinning sheets and an additional layer of resin film was used. The fabricated laminates were subjected to low velocity impacts of various energy levels to study the progressive damage and deformation mechanics of fiberglass laminates with and without electrospun nanofibers. The low velocity impact behavior was modeled using the transient dynamic finite element program LSDYNA. It was observed that the simulations results are in good agreement with the experimental results for lower impact energies. In addition, the simulated maximum impact force is smaller than the experimental value (soft response) at each drop height and at higher energy levels, the area under impact force vs time increases when electrospun nanofibers are used in the laminates. The study indicates that, the impact duration increases when electrospun nanofibers are used. Impact duration increases due to an additional damage accumulations in electrospun nanofibers layers. Both computational and experimental investigations clearly indicate that inserting interlaminar electrospun nanofiber layers improves the impact resistance of composites by absorbing additional impact energies.
Rapports d'organisations sur le sujet "Composite nanofibers"
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Ross, M. S., J. P. Kelly, L. R. Finkenauer et J. J. Haslam. Composite 4YSZ-Al2O3 Nanofibers Prepared by Electrospinning and Thermal Processing. Office of Scientific and Technical Information (OSTI), octobre 2019. http://dx.doi.org/10.2172/1571371.
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Wu, Nick, et Xiangwu Zhang. Solid-State Inorganic Nanofiber Network-Polymer Composite Electrolytes for Lithium Batteries. Office of Scientific and Technical Information (OSTI), avril 2021. http://dx.doi.org/10.2172/1779614.
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