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Sample records for hexaferrite polychloroprene nanocomposites

  1. High frequency electromagnetic reflection loss performance of substituted Sr-hexaferrite nanoparticles/SWCNTs/epoxy nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Gordani, Gholam Reza, E-mail: gordani@gmail.com [Materials Engineering Department, Malek Ashtar University of Technology, Shahin Shahr (Iran, Islamic Republic of); Ghasemi, Ali [Materials Engineering Department, Malek Ashtar University of Technology, Shahin Shahr (Iran, Islamic Republic of); Saidi, Ali [Department of Materials Science and Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)

    2015-10-01

    In this study, the electromagnetic properties of a novel nanocomposite material made of substituted Sr-hexaferrite nanoparticles and different percentage of single walled carbon nanotube have been studied. The structural, magnetic and electromagnetic properties of samples were studied as a function of volume percentage of SWCNTs by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer and vector network analysis. Well suitable crystallinity of hexaferrite nanoparticles was confirmed by XRD patterns. TEM and FESEM micrographs were shown the good homogenity and high level of dispersivity of SWCNTs and Sr-hexaferrite nanoparticles in nanocomposite samples. The VSM results shown that with increasing in amount of CNTs (0–6 vol%), the saturation of magnetization decreased up to 11 emu/g for nanocomposite sample contains of 6 vol% of SWCNTs. The vector network analysis results show that the maximum value of reflection loss was −36.4 dB at the frequency of 11 GHz with an absorption bandwidth of more than 4 GHz (<−20 dB). The results indicate that, this nanocomposite material with appropriate amount of SWCNTs hold great promise for microwave device applications. - Highlights: • We investigate the high frequency properties of Sr-hexaferrite/SWCNTs composite. • Saturation magnetization of nanocomposites is decreased with presence of SWCNTs. • The ferrite/CNTs nanocomposite sample covers whole X-band frequencies (8–12 GHz). • The ferrite/CNTs nanocomposite can be used as a potential magnetic loss material. • Nanocomposite contain 4 vol% of CNTs have shown greater than 99% of reflection loss.

  2. High frequency electromagnetic reflection loss performance of substituted Sr-hexaferrite nanoparticles/SWCNTs/epoxy nanocomposite

    Science.gov (United States)

    Gordani, Gholam Reza; Ghasemi, Ali; saidi, Ali

    2015-10-01

    In this study, the electromagnetic properties of a novel nanocomposite material made of substituted Sr-hexaferrite nanoparticles and different percentage of single walled carbon nanotube have been studied. The structural, magnetic and electromagnetic properties of samples were studied as a function of volume percentage of SWCNTs by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometer and vector network analysis. Well suitable crystallinity of hexaferrite nanoparticles was confirmed by XRD patterns. TEM and FESEM micrographs were shown the good homogenity and high level of dispersivity of SWCNTs and Sr-hexaferrite nanoparticles in nanocomposite samples. The VSM results shown that with increasing in amount of CNTs (0-6 vol%), the saturation of magnetization decreased up to 11 emu/g for nanocomposite sample contains of 6 vol% of SWCNTs. The vector network analysis results show that the maximum value of reflection loss was -36.4 dB at the frequency of 11 GHz with an absorption bandwidth of more than 4 GHz (nanocomposite material with appropriate amount of SWCNTs hold great promise for microwave device applications.

  3. Monolithic Magneto-Optical Nanocomposites of Barium Hexaferrite Platelets in PMMA.

    Science.gov (United States)

    Ferk, Gregor; Krajnc, Peter; Hamler, Anton; Mertelj, Alenka; Cebollada, Federico; Drofenik, Miha; Lisjak, Darja

    2015-06-12

    The incorporation of magnetic barium hexaferrite nanoparticles in a transparent polymer matrix of poly(methyl methacrylate) (PMMA) is reported for the first time. The barium hexaferrite nanoplatelets doped with Sc(3+), i.e., BaSc0.5Fe11.5O12 (BaHF), having diameters in the range 20 to 130 nm and thicknesses of approximately 5 nm, are synthesized hydrothermally and stabilized in 1-butanol with dodecylbenzenesulfonic acid. This method enables the preparation of monolithic nanocomposites by admixing the BaHF suspension into a liquid monomer, followed by in-situ, bulk free-radical polymerization. The PMMA retains its transparency for loadings of BaHF nanoparticles up to 0.27 wt.%, meaning that magnetically and optically anisotropic, monolithic nanocomposites can be synthesized when the polymerization is carried out in a magnetic field. The excellent dispersion of the magnetic nanoparticles, coupled with a reasonable control over the magnetic properties achieved in this investigation, is encouraging for the magneto-optical applications of these materials.

  4. Synthesis and micro-structural characterization of graphene/strontium hexaferrite (SrFe{sub 12}O{sub 19}) nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Durmus, Zehra, E-mail: zdurmus@bezmialem.edu.tr [Department of Pharmaceutical Biotechnology, Bezmialem Vakif University, 34093, Fatih, Istanbul (Turkey); Kavas, Huseyin [Department of Engineering Physics, Istanbul Medeniyet University, 34700, Kadıköy, Istanbul (Turkey); Durmus, Ali [Department of Chemical Engineering, Istanbul University, 34320, Avcılar, Istanbul (Turkey); Aktaş, Bekir [Department of Physics, Gebze Technical University, 41400, Gebze, Kocaeli (Turkey)

    2015-08-01

    In this study, novel type carbon/ferrite nanocomposites were successfully prepared by decoration of graphene sheets with the magnetic strontium hexaferrite nanoparticles synthesized via the citrate sol–gel combustion method as microwave absorbing material. The microstructural features and physical properties of nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM) methods. Magnetic properties of the nanocomposites were determined by a vibrating sample magnetometer (VSM). It was found that the surface of the graphene nanosheets were successfully decorated with the strontium hexaferrite nanoparticles and the resulting layered nanocomposite structures exhibited sufficiently high magnetic saturation values compared to the agglomerated structure of strontium hexaferrite nanoparticles although the nanocomposites include less active magnetic component than the bulk hexaferrite. - Highlights: • Novel type, two-dimensional carbon-ferrite nanocomposites were prepared. • 2D graphene sheets were successfully decorated with the SrFe{sub 12}O{sub 19} nanoparticles. • Morphologies of nanocomposites were characterized with SEM, TEM and AFM methods. • Graphene/SrFe{sub 12}O{sub 19} nanocomposites exhibited sufficiently high M{sub s} values.

  5. Radiation losses in microwave K_u region by conducting pyrrole/barium titanate and barium hexaferrite based nanocomposites

    International Nuclear Information System (INIS)

    Kaur, Talwinder; Kumar, Sachin; Narang, S.B.; Srivastava, A.K.

    2016-01-01

    Nanocomposites of substituted barium hexaferrite and barium titanate embedded in a polymer were synthesized via emulsion polymerization. The study was performed by using X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, electron spin resonance spectroscopy, a vibrating sample magnetometer and a vector network analyzer. It is found that maximum radiation loss occur at 16.09 GHz (−14.23 dB) frequency owing to the combined effect of conducting polymer, suitable dielectric and magnetic material. This suggests that prepared material is suitable for radiation losses. Micro structural study reveals the presence of all the phases of the compounds comprises composite. Benzene ring absorption band (at 1183 cm"−"1) in FT-IR spectra illustrates the presence of polymer. Surface morphology reveals the presence of array of particles encapsulated by the polymer. - Highlights: • Composites having polymer, barium titanate and hexaferrite have been successfully prepared. • Effective radiation absorption and losses have been achieved. • Magnetic properties have made an impact on shielding effectiveness.

  6. Radiation losses in microwave K{sub u} region by conducting pyrrole/barium titanate and barium hexaferrite based nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Talwinder [Department of Physics, Lovely Professional University, Phagwara 144411 (India); Kumar, Sachin [Department of Chemistry, Guru Nanak Dev University, Amritsar 143005 (India); Narang, S.B. [Department of Electronics Technology, Guru Nanak Dev University, Amritsar 143005 (India); Srivastava, A.K., E-mail: srivastava_phy@yahoo.co.in [Department of Physics, Lovely Professional University, Phagwara 144411 (India)

    2016-12-15

    Nanocomposites of substituted barium hexaferrite and barium titanate embedded in a polymer were synthesized via emulsion polymerization. The study was performed by using X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, electron spin resonance spectroscopy, a vibrating sample magnetometer and a vector network analyzer. It is found that maximum radiation loss occur at 16.09 GHz (−14.23 dB) frequency owing to the combined effect of conducting polymer, suitable dielectric and magnetic material. This suggests that prepared material is suitable for radiation losses. Micro structural study reveals the presence of all the phases of the compounds comprises composite. Benzene ring absorption band (at 1183 cm{sup −1}) in FT-IR spectra illustrates the presence of polymer. Surface morphology reveals the presence of array of particles encapsulated by the polymer. - Highlights: • Composites having polymer, barium titanate and hexaferrite have been successfully prepared. • Effective radiation absorption and losses have been achieved. • Magnetic properties have made an impact on shielding effectiveness.

  7. Nanostructured magnesium oxide as cure activator for polychloroprene rubber.

    Science.gov (United States)

    Kar, Sritama; Bhowmick, Anil K

    2009-05-01

    The aim of this research was to synthesize magnesium oxide nanoparticles and to use them as cure activator for polychloroprene rubber (CR). The effects of counterions of magnesium salts on the homogeneous phase precipitation reaction to control size, monodispersity, crystallinity, and morphology of Mg(OH)2 nanoparticles were also investigated. Magnesium oxide nanoparticles were synthesized by optimizing the calcination temperature of Mg(OH)2 nanoparticles. Finally, the MgO nanoparticles were dispersed in polychloroprene rubber (CR) solution along with zinc oxide (ZnO) powder. The influence of MgO nanoparticles on the mechanical, dynamic mechanical and thermal properties of the resulting nanocomposites was quantified. The modulus and strength of ZnO-cured polychloroprene rubber with 4% MgO nanoparticles appeared to be superior to those with ZnO particles or ZnO with rubber grade MgO particles. These composites were further characterized by transmission electron microscopy and infrared spectroscopy in order to understand the morphology of the resulting system and the load transfer mechanism.

  8. Sr hexaferrite/Ni ferrite nanocomposites: Magnetic behavior and microwave absorbing properties in the X-band

    Energy Technology Data Exchange (ETDEWEB)

    Jacobo, Silvia E. [Facultad de Ingeniería, Universidad de Buenos Aires, LAFMACEL-INTECIN, Paseo Colón 850, C1063EHA Buenos Aires (Argentina); Bercoff, Paula G., E-mail: bercoff@famaf.unc.edu.ar [Facultad de Matemática, Astronomía y Física, Universidad Nacional de Córdoba, IFEG, CONICET, Ciudad Universitaria, X5000HUA Córdoba (Argentina); Herme, Carlos A. [Facultad de Ingeniería, Universidad de Buenos Aires, LAFMACEL-INTECIN, Paseo Colón 850, C1063EHA Buenos Aires (Argentina); Vives, Leandro A. [División Antenas, Instituto de Investigaciones Científicas para la Defensa CITEDEF, Ministerio de Defensa, San Juan Bautista de La Salle 4397, Villa Martelli, B1603ALO Buenos Aires (Argentina)

    2015-05-01

    Nickel ferrite nanoparticles were synthesized by a self-combustion method over nanocrystalline powders of Nd–Co substituted strontium hexaferrite with nominal composition Sr{sub 0.5}Nd{sub 0.5}Co{sub 0.5}Fe{sub 10.5}O{sub 19}, at different mass relations. The samples were structurally characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). The M vs. H loops of the composites were determined with a vibrating sample magnetometer (VSM) and the interaction with the X-band microwave radiation of the nanocomposites dispersed in epoxy resin was measured with a vector network analyzer (VNA). The hysteresis loops showed strong exchange-coupling between the two magnetic phases for the 30:70 and 50:50 Sr{sub 0.5}Co{sub 0.5}Nd{sub 0.5}Fe{sub 10.5}O{sub 19}/NiFe{sub 2}O{sub 4} nanocomposites, while a weak interaction was observed for the 70:30 mass ratio. The nanocomposite with an equal amount of hard and soft phase shows the highest performance both in reflectivity and in bandwidth, reaching a maximum in reflectivity of −34.4 dB at 11.1 GHz while the bandwidth below −10 dB is 3.5 GHz. - Highlights: • Sr{sub 0.5}Co{sub 0.5}Nd{sub 0.5}Fe{sub 10.5}O{sub 19}/NiFe{sub 2}O{sub 4} nanocomposites were synthesized at different mass ratios. • The systems were structurally and magnetically characterized. • The X-band microwave radiation of the composites was evaluated. • Enhancement in reflectivity is related to exchange interaction between hard and soft phases.

  9. 75 FR 57980 - Polychloroprene Rubber From Japan

    Science.gov (United States)

    2010-09-23

    ... INTERNATIONAL TRADE COMMISSION [Investigation No. AA1921-129 (Third Review)] Polychloroprene Rubber From Japan AGENCY: United States International Trade Commission. ACTION: Termination of five-year... of the antidumping duty finding on polychloroprene rubber from Japan would be likely to lead to...

  10. 75 FR 38119 - Polychloroprene Rubber From Japan

    Science.gov (United States)

    2010-07-01

    ... Rubber From Japan AGENCY: United States International Trade Commission. ACTION: Institution of a five-year review concerning the antidumping duty finding on polychloroprene rubber from Japan. SUMMARY: The... on polychloroprene rubber from Japan would be likely to lead to continuation or recurrence of...

  11. Synthesis, characterization and microwave characteristics of ternary nanocomposite of MWCNTs/doped Sr-hexaferrite/PANI

    Energy Technology Data Exchange (ETDEWEB)

    Seyyed Afghahi, Seyyed Salman [Department of Materials Science and Engineering, Imam Hossein University, Tehran (Iran, Islamic Republic of); Peymanfar, Reza; Javanshir, Shahrzad [Department of Chemistry, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Atassi, Yomen [Department of Applied Physics, Higher Institute for Applied Sciences and Technology, Damascus (Syrian Arab Republic); Jafarian, Mojtaba, E-mail: m.jafarian@srbiau.ac.ir [Young Researchers and Elites Club, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2017-02-01

    Substituted strontium ferrite (sub-SF) nanoparticles are prepared by a sol-gel method and added to functionalized multiwalled carbon nanotubes (MWCNTs). The ternary nanocomposite of MWCNTs/sub-SF/polyaniline (PANI) is prepared by in-situ polymerization of aniline on MWCNTs/sub-SF reaction mixture. The morphology, structure and magnetic properties of the nanocomposites are investigated by SEM, XRD, FTIR and VSM, respectively. The microwave characteristics are measured using a vector network analyzer. The XRD patterns exhibit representative diffraction peaks corresponding to hexagonal structure, and the structure of the MWCNTs is not distorted. SEM micrographs show that sub-SF nanoparticles and PANI chains are uniformly dispersed on the surface of MWCNTs. The MWCNTs/sub-SF/PANI exhibit a minimum reflection loss of −26 dB at 10 GHz with 3 GHz bandwidth and a matching thickness of 5 mm. This excellent microwave characteristic indicates the synergistic effect of the three components to enhance the impedance matching and improve the microwave absorption properties of the composite. - Highlights: • Novel ternary nanocomposite of MWCNTs/sub-SF/polyaniline (PANI) is prepared by in-situ polymerization. • The prepared single composite absorber are lightweight with 20 wt% filler content in parafin. • Composites with a combination of magnetic and dielectric fillers exhibit wider reflection loss peaks. • Composite absorber exhibit a minimum reflection loss of −26 dB at 10 GHz with 3 GHz bandwidth with a matching thickness of 5 mm.

  12. Exchange interactions in barium hexaferrite

    Czech Academy of Sciences Publication Activity Database

    Novák, Pavel; Rusz, J.

    2005-01-01

    Roč. 71, č. 18 (2005), 184433/1-184433/6 ISSN 1098-0121 R&D Projects: GA AV ČR(CZ) IAA1010214 Institutional research plan: CEZ:AV0Z10100521 Keywords : hexaferrites * exchange interaction * density functional theory Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.185, year: 2005

  13. Elimination of the reactivation process in the adhesion of chlorinated SBS rubber with polychloroprene adhesives

    Directory of Open Access Journals (Sweden)

    2007-04-01

    Full Text Available Chlorination treatment of a thermoplastic styrene-butadiene-styrene rubber (SBS with a 3 wt% solution of trichloroisocyanuric acid (TCI in methyl ethyl ketone (MEK introduces chlorinated and oxidized moieties on the rubber surface which increase its surface energy and produces surface microroughness. Consequently adhesion properties, evaluated by T-peel strength measurements in chlorinated SBS/solvent based-polyurethane adhesive/leather joints, are enhanced. In this study, two solvent-based polychloroprene adhesives (PCP0 and PCP30R have been considered as an alternative to the commonly used solvent-based polyurethane adhesive (PU. A thermoreactive phenolic resin was added to one of the polychloroprene adhesive formulations (PCP30R. This tackifier resin favors chlorination of the adhesive and reinforces the interface between the chlorinated adhesive and the chlorinated rubber surface. Besides, PCP30R adhesive does not need adhesive reactivation and considerable high T-peel strength value (5.7±0.3 kN/m was obtained. Elimination of the reactivation process implies a considerable improvement of the manufacturing process in the footwear industry.

  14. Hexaferrite multiferroics: from bulk to thick films

    Science.gov (United States)

    Koutzarova, T.; Ghelev, Ch; Peneva, P.; Georgieva, B.; Kolev, S.; Vertruyen, B.; Closset, R.

    2018-03-01

    We report studies of the structural and microstructural properties of Sr3Co2Fe24O41 in bulk form and as thick films. The precursor powders for the bulk form were prepared following the sol-gel auto-combustion method. The prepared pellets were synthesized at 1200 °C to produce Sr3Co2Fe24O41. The XRD spectra of the bulks showed the characteristic peaks corresponding to the Z-type hexaferrite structure as a main phase and second phases of CoFe2O4 and Sr3Fe2O7-x. The microstructure analysis of the cross-section of the bulk pellets revealed a hexagonal sheet structure. Large areas were observed of packages of hexagonal sheets where the separate hexagonal particles were ordered along the c axis. Sr3Co2Fe24O41 thick films were deposited from a suspension containing the Sr3Co2Fe24O41 powder. The microstructural analysis of the thick films showed that the particles had the perfect hexagonal shape typical for hexaferrites.

  15. Effect of precursor choice and sintering conditions for W hexaferrite formation

    DEFF Research Database (Denmark)

    Mørch, Mathias; Eikeland, Anna; Christensen, Mogens

    . Hexaferrites are of great interest because of high stability, high anisotropy and favorable cost/performance ratio. This work focuses on the W-phase hexaferrite which excels with its high anisotropy constant, Curie temperature, and a higher saturation magnetization compared to other hexaferrites...

  16. Barium hexaferrite nanoparticles: Synthesis and magnetic properties

    International Nuclear Information System (INIS)

    Martirosyan, K.S.; Galstyan, E.; Hossain, S.M.; Wang Yiju; Litvinov, D.

    2011-01-01

    Carbon combustion synthesis is applied to rapid and energy efficient fabrication of crystalline barium hexaferrite nanoparticles with the average particle size of 50-100 nm. In this method, the exothermic oxidation of carbon nanoparticles with an average size of 5 nm with a surface area of 80 m 2 /g generates a self-propagating thermal wave with maximum temperatures of up to 1000 deg. C. The thermal front rapidly propagates through the mixture of solid reactants converting it to the hexagonal barium ferrite. Carbon is not incorporated in the product and is emitted from the reaction zone as a gaseous CO 2 . The activation energy for carbon combustion synthesis of BaFe 12 O 19 was estimated to be 98 kJ/mol. A complete conversion to hexagonal barium ferrite is obtained for carbon concentration exceeding 11 wt.%. The magnetic properties H c ∼3000 Oe and M s ∼50.3 emu/g of the compact sintered ferrites compare well with those produced by other synthesis methods.

  17. Radiation processed polychloroprene-co-ethylene-propene diene terpolymer blends: Effect of radiation vulcanization on solvent transport kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, K.A. [Radiation Technology Development Section, Bhabha Atomic Research Centre, Room No. S-1, HIRUP Building, Trombay, Mumbai 400 085 (India); Bhardwaj, Y.K. [Radiation Technology Development Section, Bhabha Atomic Research Centre, Room No. S-1, HIRUP Building, Trombay, Mumbai 400 085 (India)], E-mail: ykbhard@barc.gov.in; Chaudhari, C.V.; Kumar, Virendra; Goel, N.K.; Sabharwal, S. [Radiation Technology Development Section, Bhabha Atomic Research Centre, Room No. S-1, HIRUP Building, Trombay, Mumbai 400 085 (India)

    2009-03-15

    Blends of polychloroprene rubber (PCR) and ethylene propylene diene terpolymer rubber (EPDM) of different compositions were made and exposed to different gamma radiation doses. The radiation sensitivity and radiation vulcanization efficiency of blends was estimated by gel-content analysis, Charlesby-Pinner parameter determination and crosslinking density measurements. Gamma radiation induced crosslinking was most efficient for EPDM (p{sub 0}/q{sub 0} {approx} 0.08), whereas it was the lowest for blends containing 40% PCR (p{sub 0}/q{sub 0} {approx} 0.34). The vulcanized blends were characterized for solvent diffusion characteristics by following the swelling dynamics. Blends with higher PCR content showed anomalous swelling. The sorption and permeability of the solvent were not strictly in accordance with each other and the extent of variation in two parameters was found to be a function of blend composition. The {delta}G values for solvent diffusion were in the range -2.97 to -9.58 kJ/mol and indicated thermodynamically favorable sorption for all blends. These results were corroborated by dynamic swelling, experimental as well as simulated profiles and have been explained on the basis of correlation between crosslinking density, diffusion kinetics, thermodynamic parameters and polymer-polymer interaction parameter.

  18. A Comparative Study on Magnetostructural Properties of Barium Hexaferrite Powders Prepared by Polyethylene Glycol

    OpenAIRE

    Zehra Durmus

    2014-01-01

    Nanocrystalline particles of barium hexaferrite were synthesized by a sol-gel combustion route using nitrate-citrate gels prepared from metal nitrates and citric acid solutions with Fe/Ba molar ratio 12. The present paper aims to study the effect of addition of polyethylene glycol (PEG) solutions with different molecular weights (MW: 400, 2000, and 10.000 g/mol) on magnetostructural properties of barium hexaferrite. The formation of the barium hexaferrite was inspected using X-ray diffractio...

  19. Influence of Magnetron Effect on Barium Hexaferrite Thin Layers

    International Nuclear Information System (INIS)

    Hassane, H.; Chatelon, J.P.; Rousseau, J.J; Siblini, A.; Kriga, A.

    2011-01-01

    In this paper, we study the effects of a magnet, located in the cathode, on barium hexaferrite thin films deposited by RF magnetron sputtering technique. During the process, these effects can modify thickness, roughness and stress of coatings. The characteristics of the deposited layers depend on the substrate position that is located opposite of magnetron cathode. In the m agnetron area , one can observe that the high stress can produce cracks or detachment of layers and the increasing of both depositing rate and surface roughness. After sputtering elaboration, barium hexaferrite films are in a compressive stress mode. But, after the post-deposition heat treatment these films are in a tensile stress mode. To improve the quality of BaM films, the subsrtate has to be set outside the magnetron area. (author)

  20. Thermal evolution of exchange interactions in lightly doped barium hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Trukhanov, S.V., E-mail: truhanov@ifttp.bas-net.by [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); SSPA “Scientific and practical materials research centre of NAS of Belarus”, P. Brovki Str., 19, 220072 Minsk, Belorussia (Belarus); Trukhanov, A.V. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); SSPA “Scientific and practical materials research centre of NAS of Belarus”, P. Brovki Str., 19, 220072 Minsk, Belorussia (Belarus); Kostishyn, V.G.; Panina, L.V. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); Turchenko, V.A. [Joint Institute for Nuclear Research, Joliot-Curie Str., 141980 Dubna (Russian Federation); Donetsk Institute of Physics and Technology named after A.A. Galkin of the NAS of Ukraine, 72 R.Luxemburg Str., 83114 Donetsk (Ukraine); Kazakevich, I.S. [SSPA “Scientific and practical materials research centre of NAS of Belarus”, P. Brovki Str., 19, 220072 Minsk, Belorussia (Belarus); Trukhanov, An.V. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); SSPA “Scientific and practical materials research centre of NAS of Belarus”, P. Brovki Str., 19, 220072 Minsk, Belorussia (Belarus); Trukhanova, E.L.; Natarov, V.O. [SSPA “Scientific and practical materials research centre of NAS of Belarus”, P. Brovki Str., 19, 220072 Minsk, Belorussia (Belarus); Balagurov, A.M. [Joint Institute for Nuclear Research, Joliot-Curie Str., 141980 Dubna (Russian Federation)

    2017-03-15

    The lightly doped BaFe{sub 12−x}D{sub x}O{sub 19} (D=Al{sup 3+}, In{sup 3+}; x=0.1 and 0.3) polycrystalline hexaferrite samples have been investigated by powder neutron diffractometry as well as by vibration sample magnetometry in a wide temperature range from 4 K up to 740 K and in magnetic field up to 14 T to establish the nature of Fe{sup 3+}(Al{sup 3+}, In{sup 3+}) – O{sup 2-} - Fe{sup 3+}(Al{sup 3+}, In{sup 3+}) indirect exchange interactions. The crystal structure features such as the ionic coordinates and lattice parameters have been defined and Rietveld refined. The Invar effect has been observed in low temperature range below 150 K. It was explained by the thermal oscillation anharmonicity of ions. It is established that the ferrimagnet-paramagnet phase transition is a standard second-order one. From the macroscopic magnetization measurement the Curie temperature and ordered magnetic moment per nominal iron ion are obtained. From the microscopic diffraction measurement the magnetic moments at all the nonequivalent ionic positions and total magnetic moment per iron ion have been obtained at different temperatures down to 4 K. The light diamagnetic doping mechanism and magnetic structure model are proposed. The effect of light diamagnetic doping on nature of Fe{sup 3+}(Al{sup 3+}, In{sup 3+}) – O{sup 2-} - Fe{sup 3+}(Al{sup 3+}, In{sup 3+}) indirect exchange interactions with temperature increase is discussed. - Highlights: • Crystal structure for lightly doped barium hexaferrites was investigated. • Atomic coordinates and lattice parameters were Rietveld refined. • Magnetic properties for lightly doped barium hexaferrites was investigated. • Magnetic structure for lightly doped barium hexaferrites was investigated. • Magnetic moments at different position and total moment per iron ion were defined.

  1. Crystal structure, magnetic properties and advances in hexaferrites: A brief review

    Science.gov (United States)

    Jotania, Rajshree

    2014-10-01

    Hexaferrites are hard magnetic materials and specifically ferri-magnetic oxides with hexagonal magnetoplumbite type crystallographic structure. Hexagonal ferrites are used as permanent magnets, high-density perpendicular and magneto-optical recording media, and microwave devices like resonance isolators, filters, circulators, phase shifters because of their high magnetic permeability, high electrical resistivity and moderable permittivity. In addition to these; hexagonal ferrites have excellent chemical stability, mechanical hardness and low eddy current loss at high frequencies. The preparation of hexaferrites is a complicated process. Various experimental techniques like standard ceramic techniques, solvent free synthesis route, co precipitation, salt-melt, ion exchange, sol-gel, citrate synthesis, hydrothermal synthesis, spray drying, water-in-oil microemulsion, reverse micelle etc are used to prepare hexaferrite materials. Structural, dielectric and magnetic properties, crystallite size of hexaferrites depend upon nature of substituted ions, method of preparation, sintering temperature and time. The recent interest is nanotechnology, the development of hexaferrite fibres and composites with carbon nano tubes (CNT). Magnetic properties of some doped and un-doped hexaferrites are discussed here. Recent advances in hexaferrites also highlighted in present paper.

  2. A Comparative Study on Magnetostructural Properties of Barium Hexaferrite Powders Prepared by Polyethylene Glycol

    Directory of Open Access Journals (Sweden)

    Zehra Durmus

    2014-01-01

    Full Text Available Nanocrystalline particles of barium hexaferrite were synthesized by a sol-gel combustion route using nitrate-citrate gels prepared from metal nitrates and citric acid solutions with Fe/Ba molar ratio 12. The present paper aims to study the effect of addition of polyethylene glycol (PEG solutions with different molecular weights (MW: 400, 2000, and 10.000 g/mol on magnetostructural properties of barium hexaferrite. The formation of the barium hexaferrite was inspected using X-ray diffraction (XRD analysis, Fourier transform infrared (FT-IR analysis, thermogravimetric (TGA analysis, scanning electron microscopy (SEM analysis and vibrating sample magnetometer (VSM analysis for magnetic measurements.

  3. Multiple electrical phase transitions in Al substituted barium hexaferrite

    Science.gov (United States)

    Kumar, Sunil; Supriya, Sweety; Kar, Manoranjan

    2017-12-01

    Barium hexaferrite is known to be a very good ferromagnetic material. However, it shows very good dielectric properties, i.e., the dielectric constant is comparable to that of the ferroelectric material. However, its crystal symmetry does not allow it to be a ferroelectric material. Hence, the electrical properties have revived the considerable research interest on these materials, not only for academic interest, but also for technological applications. There are a few reports on temperature dependent dielectric behavior of these materials. However, the exact cause of dielectric as well as electrical conductivity is yet to be established. Hence, Al (very good conducting material) substituted barium hexaferrite (BaFe12-xAlxO19, x = 0.0-4.0) has been prepared by following the modified sol-gel method to understand the ac and DC electrical properties of these materials. The crystal structure and parameters have been studied by employing the XRD and FTIR techniques. There are two transition temperatures, which have been observed in the temperature dependent ac dielectric and DC resistivity measurement. The response of dielectric behaviors to temperature is similar to that of the ferroelectric material; however, the dielectric polarization is due to the polaron hopping, which is evident from the DC resistivity analysis. Hence, the present observations lead to understand the electrical properties of barium hexaferrite. The frequency dependent dielectric dispersion can be understood by the modified Debye model. More interestingly, the dielectric constant decreases and DC resistivity increases with the increase in the Al concentration, which has the correlation between bond length modifications in the crystal due to substitution.

  4. Structure and multiferroic properties of barium hexaferrite ceramics

    International Nuclear Information System (INIS)

    Tan, Guolong; Chen, Xiuna

    2013-01-01

    Simultaneous occurrence of large ferroelectricity and strong ferromagnetism have been observed in barium hexaferrite ceramics. Barium hexaferrite (BaFe 12 O 19 ) powders with hexagonal crystal structure were successfully synthesized in a polymer precursor method using barium acetate and ferric acetylacetonate as the precursors. The powders were pressed into pellets which were sintered into ceramics at 1200 °C and 1300 °C for 1 h. The structure and morphology of the ceramics were examined using X-ray diffraction and field emission scanning electron microscopy. Large spontaneous polarization was observed in the BaFe 12 O 19 ceramics at room temperature, revealing a clear ferroelectric hysteresis loop. The maximum remanent polarization of the BaFe 12 O 19 ceramic was estimated approximately 11.8 μC cm −2 . The FeO 6 octahedron in its perovskite-like hexagonal unit cell and the shift of Fe 3+ off the center of octahedron are suggested to be the origin of the polarization in BaFe 12 O 19 . The BaFe 12 O 19 ceramics also showed strong ferromagnetism at room temperature. - Graphical abstract: Ferroelectric hysteresis loops of BaFe 12 O 19 ceramics measured at a frequency of 120 Hz, which shows that the ceramics sintered at 1200 °C is ferroelectric with P r ∼11.8 μC/cm 2 . Highlights: ► Large ferroelectricity and strong ferromagnetism were observed in barium hexaferrite ceramics. ► The maximum remanent polarization of the BaFe 12 O 19 ceramic was estimated to be 11.8 μC cm −2 . ► The FeO 6 octahedron and off-center shift of Fe 3+ are suggested to be the origin of the polarization.

  5. Crystal structure and magnetic properties of Cr doped barium hexaferrite

    Science.gov (United States)

    Kumar, Sunil; Supriya, Sweety; Pandey, Rabichandra; Pradhan, Lagen Kumar; Kar, Manoranjan

    2018-04-01

    The Cr3+ substituted BaFe12O19 has been synthesized by modified sol-gel method to tailor the magnetic anisotropy and coercivity for technological applications. Some basic studies have revealed that this substitution leads to unusual interactions among the magnetic sublattices of the M-type hexaferrite. In order to investigate these interactions, BaFe12-xCrxO19 (x = 0.0, 0.5, 1.0, 2.0, and 4.0) M-type hexaferrites were characterized by employing XRD (X-ray Diffractometer). It is confirmed that, all the samples are in nanocrystalline and single phase, no impurity has been detected within the XRD limit. The magnetic hysteresis (m-H) loops revealed the ferromagnetic nature of nanoparticles (NPs). The coercive field were increasing with the increasing Cr3+ content, but after the percolation limit it decreases. The magnetocrystalline anisotropy is increasing with the Cr3+ concentration in samples and high values of magnetocrystalline anisotropy revealed that all samples are hard magnetic materials. Magnetic hysteresis loops were analyzed using the Law of Approach to Saturation method.

  6. Preparation of strontium hexaferrite magnets from celestite and blue dust by mechanochemical route

    Directory of Open Access Journals (Sweden)

    Tiwary R.K.

    2008-01-01

    Full Text Available In the present investigation celestite (natural ore of strontium and blue dust (iron ore fines have been used for the preparation of strontium hexaferrite powder. The mechanical alloying process has been adopted to prepare strontium hexaferrite powder. The celestite after chemical upradation and physically upgraded blue dust alongwith sodium carbonate was taken for the preparation of strontium hexaferrite in this experiment. The high-energy planetary ball mill with tungsten carbide jar and ball was used to prepare strontium hexaferrite powder. A long time of ball milling for different duration has led to displacement solid-state reaction. At the end of each experiment the product was washed thoroughly and dried. The X-ray diffaction study after annealing shows the development of single-phase strontium hexaferrite after 40 hrs. of milling. The resultant powder was compacted under magnetic field and sintered to prepare the magnet after annealing the ferrite powder. The magnetic properties were measured by Pulse magneto meter. The moderate value of coercivity, remanence and energy product were observed in this sintered magnet. The work illustrates the feasibility to prepare strontium hexaferrite magnetic powders directly from natural ores which can reduce the total cost of production as compared to conventional method.

  7. Tunable ferromagnetic resonance in La-Co substituted barium hexaferrites at millimeter wave frequencies

    Science.gov (United States)

    Korolev, Konstantin A.; Wu, Chuanjian; Yu, Zhong; Sun, Ke; Afsar, Mohammed N.; Harris, Vincent G.

    2018-05-01

    Transmittance measurements have been performed on La-Co substituted barium hexaferrites in millimeter waves. Broadband millimeter-wave measurements have been carried out using the free space quasi-optical spectrometer, equipped with a set of high power backward wave oscillators covering the frequency range of 30 - 120 GHz. Strong absorption zones have been observed in the millimeter-wave transmittance spectra of all La-Co substituted barium hexaferrites due to the ferromagnetic resonance. Linear shift of ferromagnetic resonance frequency as functions of La-Co substitutions have been found. Real and imaginary parts of dielectric permittivity of La-Co substituted barium hexaferrites have been calculated using the analysis of recorded high precision transmittance spectra. Frequency dependences of magnetic permeability of La-Co substituted barium hexaferrites, as well as saturation magnetization and anisotropy field have been determined based on Schlömann's theory for partially magnetized ferrites. La-Co substituted barium hexaferrites have been further investigated by DC magnetization to assess magnetic behavior and compare with millimeter wave data. Consistency of saturation magnetization determined independently by both millimeter wave absorption and DC magnetization have been found for all La-Co substituted barium hexaferrites. These materials seem to be quite promising as tunable millimeter wave absorbers, filters, circulators, based on the adjusting of their substitution parameters.

  8. A promising lightweight multicomponent microwave absorber based on doped barium hexaferrite/calcium titanate/multiwalled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Afghahi, Seyyed Salman Seyyed [Imam Hossein University, Department of Materials Science and Engineering (Iran, Islamic Republic of); Jafarian, Mojtaba, E-mail: m.jafarian@srbiau.ac.ir [Islamic Azad University, Young Researchers and Elite Club, Science and Research Branch (Iran, Islamic Republic of); Atassi, Yomen [Higher Institute for Applied Sciences and Technology, Department of Applied Physics (Syrian Arab Republic)

    2016-07-15

    We present the design of a microwave absorber in the X band based on ternary nanocomposite of doped barium hexaferrite (Ba-M)/calcium titanate (CTO)/multiwall carbon nanotubes (MWCNTs) in epoxy matrix. The hydrothermal method has been used to synthesize Ba-M and CTO nanopowder. The phase identification has been investigated using XRD patterns. Scanning electron microscope, transmission electron microscope, vibrating sample magnetometer, and vector network analyzer are used to analyze the morphology of the different components and the magnetic, electromagnetic, and microwave absorption properties of the final composite absorbers, respectively. As far as we know, the design of this type of multicomponent microwave absorber has not been investigated before. The results reveal that the combination of these three components with their different loss mechanisms has a synergistic effect that enhances the attenuation properties of the final composite. The absorber of only 2.5-mm thickness and 35 wt% of loading ratio exhibits a minimum reflection loss of −43 dB at 10.2 GHz with a bandwidth of 3.6 GHz, while the corresponding absorber based on pure (Ba-M) shows a minimum reflection loss of −34 dB at 9.8 GHz with a bandwidth of 0.256 GHz and a thickness of 4 mm.Graphical Abstract.

  9. Attainment of barium hexaferrite nanoparticles by a Pechini Method

    International Nuclear Information System (INIS)

    Galvao, S.B.; Timoteo, Jr.J.F.; Melo, G.M.; Souto, K.K.O.; Florioto, N.T.; Paskocimas, C.A.

    2009-01-01

    The barium hexaferrites (BaFe 12 O 19 ) are used as a compound of materials applied in electronic devices, as medical devices, satellites, dada servers systems, wireless systems and others. The general properties are strongly related to the microstructure and morphology, and the particles size decrease results in advantages to the majority applications, mainly the high-tech thumbnail devices. These magnetic ceramic materials, with perovskite structure, are traditionally prepared my conventional oxide mixture synthesis. In this work was studied the nanoparticle synthesis of BaFe 12 O 19 by the precursors polymeric method (Pechini), using as precursors the barium carbonate and the iron nitrate, under different thermal treatment conditions. The samples were characterized by XRD, SEM, BET, DTA and TGA. The results presented the attainment of a monophasic powder with particles size around 100 nm. (author)

  10. Structural and magnetic properties of barium-gadolinium hexaferrites

    Science.gov (United States)

    Litsardakis, G.; Manolakis, I.; Serletis, C.; Efthimiadis, K. G.

    A series of Gd-substituted M-type barium hexaferrites has been prepared by the ceramic route, according to the formula (Ba 1-xGd x)O·5.25Fe 2O 3 ( x=0-0.30). XRD analysis revealed that all the samples present primarily an M-type structure. Samples x=0 and x=0.05 are single-phase. Hematite (Fe 2O 3) and GdFeO 3 were detected in the remaining samples. Coercivity ( Hc) shows remarkably high values, ˜293 kA/m for x=0.20 and 0.30 with a maximum of 322 kA/m for x=0.25. Specific saturation magnetization ( σsat) of the samples presents a small increase up to x=0.10. The microstructure examination indicates that Gd may act as a grain growth inhibitor.

  11. Soft x-ray resonant diffraction study of magnetic structure in magnetoelectric Y-type hexaferrite

    Science.gov (United States)

    Ueda, H.; Tanaka, Y.; Wakabayashi, Y.; Kimura, T.

    2018-05-01

    The effect of magnetic field on the magnetic structure associated with magnetoelectric properties in a Y-type hexaferrite, Ba1.3Sr0.7CoZnFe11AlO22, was investigated by utilizing the soft x-ray resonant diffraction technique. In this hexaferrite, the so-called alternating longitudinal conical phase is stabilized at room temperature and zero magnetic field. Below room temperature, however, this phase is transformed into the so-called transverse conical phase by applying an in-plane magnetic field (≈ 0.3 T). The transverse conical phase persists even after removing the magnetic field. The magnetoelectricity, which is magnetically-induced electric polarization, observed in the hexaferrite is discussed in terms of the temperature-dependent magnetic structure at zero field.

  12. Low-loss Z-type hexaferrite (Ba3Co2Fe24O41) for GHz antenna applications

    Science.gov (United States)

    Lee, Woncheol; Hong, Yang-Ki; Park, Jihoon; LaRochelle, Gatlin; Lee, Jaejin

    2016-09-01

    We report a low magnetic loss Ba3Co2Fe24O41 (Co2Z) hexaferrite for use in gigahertz (GHz) antennas. Acid-etching was very effective in removal of unwanted Y-type hexaferrite (Ba2Co2Fe12O22) from calcined Co2Z powder. It is found that the calcined and acid etched (AE) Co2Z hexaferrite shows a low magnetic loss tangent (tan δμ) of 0.012 and 0.037 at 1 and 2 GHz, respectively. These low tan δμ are attributed to removal of Y-type hexaferrite, which possesses a lower anisotropy field (Hk) than W-type hexaferrite (BaCo2Fe16O27). The figure of merit (FOM) of the AE Co2Z hexaferrite is 141.7 and 48.7 at 1 and 2 GHz, respectively. These FOM are much higher than the FOM of previously reported low-loss magnetic materials. Therefore, the AE Co2Z hexaferrite can be a good candidate for GHz antenna application in the ultra-high frequency (UHF) band.

  13. Deposition of magnetoelectric hexaferrite thin films on substrates of silicon

    Energy Technology Data Exchange (ETDEWEB)

    Zare, Saba; Izadkhah, Hessam; Vittoria, Carmine

    2016-12-15

    Magnetoelectric M-type hexaferrite thin films (SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19}) were deposited using Pulsed Laser Deposition (PLD) technique on Silicon substrate. A conductive oxide layer of Indium-Tin Oxide (ITO) was deposited as a buffer layer with the dual purposes of 1) to reduce lattice mismatch between the film and silicon and 2) to lower applied voltages to observe magnetoelectric effects at room temperature on Silicon based devices. The film exhibited magnetoelectric effects as confirmed by vibrating sample magnetometer (VSM) techniques in voltages as low as 0.5 V. Without the oxide conductive layer the required voltages to observe magnetoelectric effects was typically about 1000 times larger. The magnetoelectric thin films were characterized by X-ray diffractometer, scanning electron microscope, energy-dispersive spectroscopy, vibrating sample magnetometer, and ferromagnetic resonance techniques. We measured saturation magnetization of 650 G, and coercive field of about 150 Oe for these thin films. The change in remanence magnetization was measured in the presence of DC voltages and the changes in remanence were in the order of 15% with the application of only 0.5 V (DC voltage). We deduced a magnetoelectric coupling, α, of 1.36×10{sup −9} s m{sup −1} in SrCo{sub 2}Ti{sub 2}Fe{sub 8}O{sub 19} thin films.

  14. Synthesis and characterization of polyaniline-hexaferrite composites

    Energy Technology Data Exchange (ETDEWEB)

    Khursheed, Tooba [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Islam, M.U., E-mail: dr.misbahulislam@bzu.edu.pk [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Asif Iqbal, M. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); College of E & ME, National University of Science and Technology, Islamabad (Pakistan); Ali, Irshad, E-mail: irshadalibzu@gmail.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Shakoor, Abdul [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Awan, M.S. [Center for Micro and Nano Devices Department of Physics, COMSATS Institute of Information Technology, Islamabad (Pakistan); Iftikhar, Aisha [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Azhar Khan, Muhammad [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Naeem Ashiq, Muhammad [Institute of Chemical Science, Bahauddin Zakariya University, Multan 60800 (Pakistan)

    2015-11-01

    Polyaniline was synthesized by chemical polymerization using aniline as monomer, and Y-type hexaferrite with composition (Co{sub 2}Mn{sub 2}Sr{sub 1.66}Nd{sub 0.4}Fe{sub 10}O{sub 22}) was prepared by co-precipitation assisted by surfactant. Three composites of Polyaniline with different ferrite ratios were prepared by mechanical blending. The synthesized samples were characterized by X-Ray diffraction, Scanning electron microscopy and electrical measurements. The XRD analysis reveals that no second phase was observed in Y-type hexagonal ferrite. In PANI-Ferrite composites, significant changes in resistivity, real and imaginary part of complex permittivity were observed with the increase of ferrite in the polyaniline matrix. At low frequencies the magnitude of dielectric constant and complex permittivity is high with few relaxation peaks. AC conductivity of PANI-Ferrite composites increase with the increase of frequency following Jonscher law. The resistivity and activation energy were found to show similar behavior. - Highlights: • Co{sub 2}Mn{sub 2}Sr{sub 1.66}Nd{sub 0.4}Fe{sub 10}O{sub 22} was prepared by co-precipitation. • Polyaniline was synthesized by chemical polymerization. • AC conductivity increase with the increase of frequency. • The resistivity and activation energy were found to show similar behavior.

  15. Structural and magnetic properties of barium-gadolinium hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Litsardakis, G. [Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece)]. E-mail: Lits@eng.auth.gr; Manolakis, I. [Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece); Serletis, C. [Department of Physics, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece); Efthimiadis, K.G. [Department of Physics, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece)

    2007-03-15

    A series of Gd-substituted M-type barium hexaferrites has been prepared by the ceramic route, according to the formula (Ba{sub 1-x}Gd{sub x})O.5.25Fe{sub 2}O{sub 3} (x=0-0.30). XRD analysis revealed that all the samples present primarily an M-type structure. Samples x=0 and x=0.05 are single-phase. Hematite (Fe{sub 2}O{sub 3}) and GdFeO{sub 3} were detected in the remaining samples. Coercivity (H{sub c}) shows remarkably high values, {approx}293kA/m for x=0.20 and 0.30 with a maximum of 322kA/m for x=0.25. Specific saturation magnetization ({sigma}{sub sat}) of the samples presents a small increase up to x=0.10. The microstructure examination indicates that Gd may act as a grain growth inhibitor.

  16. Effect of pb on the magnetic interactions of the M-type hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, A.L., E-mail: azdlobo@gmail.com [Instituto de Física de la Universidad Autónoma de San Luis Potosí, Álvaro Obregón No. 64, Col. Centro, San Luis Potosí, S.L.P. 78000, México (Mexico); Mirabal-García, M. [Instituto de Física de la Universidad Autónoma de San Luis Potosí, Álvaro Obregón No. 64, Col. Centro, San Luis Potosí, S.L.P. 78000, México (Mexico); Palomares-Sánchez, S.A.; Martínez, J.R. [Facultad de Ciencias de la Universidad Autónoma de San Luis Potosí, Álvaro Obregón No. 64, Col. Centro, San Luis Potosí, S.L.P. 78000, México (Mexico)

    2016-02-01

    This work reports the magnetic interactions of M-type lead hexaferrites. The samples were prepared using the solid state reaction method varying the lead concentration and compensating its lost by thermal treatment in order to obtain pure phases. The structural characterization was made through X-ray diffraction and the Rietveld refinement method. The morphology and grain-growth analysis were carried out using scanning electron microscopy. The magnetic interactions were studied through isothermal remanence (IRM) and DC demagnetization (DCD) remanence curves and through the construction of Henkel plots. By analyzing deviations from the Stoner–Wohlfarth model for non-interacting particles, it was determined the way in which lead modifies the interaction state in the hexaferrites. The experimental results show that the demagnetizing interactions prevail in systems with high lead content, and as lead concentration diminishes the intensity of magnetic interactions also decreases giving rise to magnetizing interactions - Highlights: • Construction of Henkel Plots of substituted hexaferrites. • Evaluation of magnetostatic and exchange interactions. • Effect of lead substitution on magnetic properties of the hexaferrites.

  17. Magnetic studies of cobalt doped barium hexaferrite nanoparticles prepared by modified sol-gel method

    International Nuclear Information System (INIS)

    Shalini, M. Govindaraj; Sahoo, Subasa C.

    2016-01-01

    M-type barium hexaferrite (BaFe_1_2O_1_9) and cobalt doped barium hexaferrite (BaFe_1_1CoO_1_9) nanopowders were synthesized by modified sol-gel auto-combustion technique and were annealed at 900°C in air for 4 hours. The annealed powders were studied in the present work and X-ray diffraction studies showed pure phase formation after annealing. The average grain size in the nanopowder sample was decreased after doping. Magnetization value of 60 emu/g was observed at 300 K for the barium hexaferrite and was reduced to 54 emu/g after doping. The coercivity of 5586 Oe was observed at 300 K for the undoped sample and was found to be decreased in the doped sample. As the measurement temperature was decreased from 300 K to 60 K, magnetization value was increased in both the samples compared to those at 300 K. The coercivity of the undoped sample was found to decrease whereas it was increased for the doped sample at 60 K. The observed magnetic properties may be understood on the basis of modified exchange interaction and anisotropy in the doped sample compared to that of pure barium hexaferrite.

  18. Improvement of high-frequency characteristics of Z-type hexaferrite by dysprosium doping

    International Nuclear Information System (INIS)

    Mu Chunhong; Liu Yingli; Song Yuanqiang; Wang Liguo; Zhang Huaiwu

    2011-01-01

    Z-type hexaferrite has great potential applications as anti-EMI material for magnetic devices in the GHz region. In this work, Dy-doped Z-type hexaferrites with nominal stoichiometry of Ba 3 Co 2 Dy x Fe 24-x O 41 (x 0.0, 0.05, 0.5, 1.0) were prepared by an improved solid-state reaction method. The effects of rare earth oxide (Dy 2 O 3 ) addition on the phase composition, microstructure and electromagnetic properties of the ceramics were investigated. Structure and micromorphology characterizations indicate that certain content of Dy doping will cause the emergence of the second phase Dy 3 Fe 5 O 12 at the grain boundaries of the majority phase Z-type hexaferrite, due to which the straightforward result is the grain refinement during the successive sintering process. Permeability spectra measurements show that the initial permeability reaches its maximum of 17 at 300 MHz with x = 0.5, while the cutoff frequency keeps above 800 MHz. The apparent specific anisotropy field H K of Dy-doped Z-type hexaferrites decreases with x increasing. The relationships among phase composition, grain size, permeability spectra, and anisotropy are theoretically investigated, and according to the analysis, Dy doping effects on its magnetic properties can be well explained and understood.

  19. Composite nanoplatelets combining soft-magnetic iron oxide with hard-magnetic barium hexaferrite

    Science.gov (United States)

    Primc, D.; Makovec, D.

    2015-01-01

    By coupling two different magnetic materials inside a single composite nanoparticle, the shape of the magnetic hysteresis can be engineered to meet the requirements of specific applications. Sandwich-like composite nanoparticles composed of a hard-magnetic Ba-hexaferrite (BaFe12O19) platelet core in between two soft-magnetic spinel iron oxide maghemite (γ-Fe2O3) layers were synthesized using a new, simple and inexpensive method based on the co-precipitation of Fe3+/Fe2+ ions in an aqueous suspension of hexaferrite core nanoparticles. The required close control of the supersaturation of the precipitating species was enabled by the controlled release of the Fe3+ ions from the nitrate complex with urea ([Fe((H2N)2C&z.dbd;O)6](NO3)3) and by using Mg(OH)2 as a solid precipitating agent. The platelet Ba-hexaferrite nanoparticles of different sizes were used as the cores. The controlled coating resulted in an exclusively heterogeneous nucleation and the topotactic growth of the spinel layers on both basal surfaces of the larger hexaferrite nanoplatelets. The direct magnetic coupling between the core and the shell resulted in a strong increase of the energy product |BH|max. Ultrafine core nanoparticles reacted with the precipitating species and homogeneous product nanoparticles were formed, which differ in terms of the structure and composition compared to any other compound in the BaO-Fe2O3 system.By coupling two different magnetic materials inside a single composite nanoparticle, the shape of the magnetic hysteresis can be engineered to meet the requirements of specific applications. Sandwich-like composite nanoparticles composed of a hard-magnetic Ba-hexaferrite (BaFe12O19) platelet core in between two soft-magnetic spinel iron oxide maghemite (γ-Fe2O3) layers were synthesized using a new, simple and inexpensive method based on the co-precipitation of Fe3+/Fe2+ ions in an aqueous suspension of hexaferrite core nanoparticles. The required close control of the

  20. The magnetic properties of aligned M hexa-ferrite fibres

    International Nuclear Information System (INIS)

    Pullar, R.C.; Bhattacharya, A.K.

    2006-01-01

    Aligned and random fibres of strontium hexa ferrite (SrM, SrFe 12 O 19 ) and barium hexaferrite (BaM, BaFe 12 O 19 ) were manufactured by blow spinning from an aqueous inorganic sol-gel precursor, which was then fired to give the hexagonal ferrite fibre. Their magnetic properties were studied by VSM, investigating the evolution of these properties with firing and measurement temperature, and in particular the effects of fibre alignment. It has been predicted that aligned ferrite fibres will demonstrate an enhanced magnetisation along the axis of alignment with respect to perpendicular to the axis, and this has been demonstrated here for the first time. The optimum firing temperature was 1000 deg. C, at which point they still had submicron grains. In BaM random fibres M s =63.8 emu g -1 and H c =428.1 kA m -1 , and in SrM random fibres M s =63.3 emu g -1 and H c =452.8 kA m -1 , high values for polycrystalline materials. Fibres aligned parallel to the applied field had saturation magnetisation (M s ) values equal to those of the random fibres, whilst fibres aligned perpendicular to the field had M s values 62% and 75% lower, for BaM and SrM, respectively. There was no change in coercivity (H c ) between random or aligned fibres of any orientation, and fibres aligned 45 deg. and parallel to H appeared identical. Therefore, properties along the axis of alignment were superior when compared to measurements perpendicular to the axis of alignment, giving a directionality to the magnetisation in an otherwise randomly oriented ferrite material

  1. Structural and Magnetic Behavioral Improvisation of Nanocalcium Hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Sable, Sharad N., E-mail: sharadtz@hotmail.co [Department of Applied Physics, Priyadarshini College of Engineering, Nagpur (India); Rewatkar, Kishor G. [Department of Physics, Dr. Ambedkar College, Dikshabhumi, Nagpur (India); Nanoti, Vivek M. [Priyadarshini College of Engineering, Nagpur (India)

    2010-04-15

    In modern technoscientific era, the industrial application of nanomaterials has grabbed a paramount importance owing to their improved characteristics. Hexagonal ferrites especially M-type ferrites have been proved to be the promising candidates for nanomaterials by virtue of their ease of applicability in high density recording media, microwave absorption devices, magneto-optic recording media, etc. Keeping a bird's view over, the samples of varied combinations of M-type substituted hexaferrites are synthesized using sol-gel combustion route by blending nitrates and chlorides as oxidants accompanied with fuels like urea, glycine, citric acid, etc. as reducing agents. The substitution of Co{sup 2+} and Sn{sup 4+} ions lie essentially in the octahedral and tetrahedral sites. As the Fe{sup 3+} ions are being replaced by Co{sup 2+} and Sn{sup 4+} ions, the probability of having oxygen vacancies in the structure was found to be greatly reduced. The magnetic particles produced by conventional solid state reactions are often larger than those produced by sol-gel combustion route. Larger particles of magnetic oxides generally exhibit multidomain magnetic structure whereas nanosized particles generally exhibit single domain magnetic structure. The simultaneous or coupled divalent and tetravalent substitution of Co{sup 2+} and Sn{sup 4+} for Fe{sup 3+} ions greatly helps to improvise the magnetic parameters such as Curie temperature, coercivity, remanent magnetization, saturation magnetization, etc. The structural comparison is being analyzed through the XRD, TEM. The samples so synthesized are found to be reseasonably homogeneous and the average particle size of the sample synthesized is found to be in the nanorange. The structural and magnetic properties are observed be improved upon those of the samples reported earlier. This confirms the more viability of such samples in the various applications of digital data devices. Further attempts could possibly lead to

  2. Radiation losses in the microwave Ku band in magneto-electric nanocomposites

    Directory of Open Access Journals (Sweden)

    Talwinder Kaur

    2015-08-01

    Full Text Available A study on radiation losses in conducting polymer nanocomposites, namely La–Co-substituted barium hexaferrite and polyaniline, is presented. The study was performed by means of a vector network analyser, X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, electron spin resonance spectroscopy and a vibrating sample magnetometer. It is found that the maximum loss occurs at 17.9 GHz (−23.10 dB, 99% loss which is due to the composition of a conducting polymer and a suitable magnetic material. A significant role of polyaniline has been observed in ESR. The influence of the magnetic properties on the radiation losses is explained. Further studies revealed that the prepared material is a nanocomposite. FTIR spectra show the presence of expected chemical structures such as C–H bonds in a ring system at 1512 cm−1.

  3. Polymer Nanocomposites

    Indian Academy of Sciences (India)

    methods for the synthesis of polymer nanocomposites. In this article we .... ers, raw materials recovery, drug delivery and anticorrosion .... region giving rise to dose-packed absorption bands called an IR ... using quaternary ammonium salts.

  4. Effects of Gd substitution on the structural and magnetic properties of strontium hexaferrites

    Science.gov (United States)

    Litsardakis, G.; Manolakis, I.; Serletis, C.; Efthimiadis, K. G.

    2007-09-01

    The effect of Gd substitution in M-type strontium hexaferrites has been examined in two series of samples, (Sr1-xGdx)O·5.25Fe2O3 and Sr1-xGdxFe12-xCoxO19, both prepared by the ceramic method, where x=0-0.40. The samples have been characterized by XRD, VSM and SEM-EDAX techniques. All substituted samples present primarily the hexaferrite structure. Sample (Sr0.95Gd)O·5.25Fe2O3 is single phase. Formation of impurity phases is affected by stoichiometry and presence of Co. In Sr-Gd samples, coercivity showed a maximum value of 305 kA/m (3.8 kOe) for x=0.20, while remanence and saturation magnetization did not decrease. Coercivity and magnetization in the Sr-Gd-Co series decreased steadily with substitution degree.

  5. Rare earth doped M-type hexaferrites; ferromagnetic resonance and magnetization dynamics

    Directory of Open Access Journals (Sweden)

    Vipul Sharma

    2018-05-01

    Full Text Available M-type hexagonal barium ferrites come in the category of magnetic material that plays a key role in electromagnetic wave propagation in various microwave devices. Due to their large magnetic anisotropy and large magnetization, their operating frequency exceeds above 50 GHz. Doping is a way to vary its magnetic properties to such an extent that its ferromagnetic resonance (FMR response can be tuned over a broad frequency band. We have done a complete FMR study of rare earth elements neodymium (Nd and samarium (Sm, with cobalt (Co as base, doped hexaferrite nanoparticles (NPs. X-ray diffractometry, vibrating sample magnetometer (VSM, and ferromagnetic resonance (FMR techniques were used to characterize the microstructure and magnetic properties of doped hexaferrite nanoparticles. Using proper theoretical electromagnetic models, various parameters are extracted from FMR data which play important role in designing and fabricating high-frequency microwave devices.

  6. Preparation and magnetic characterization of Y-type hexaferrites containing zinc, cobalt and copper

    International Nuclear Information System (INIS)

    Bai Yang; Zhou Ji; Gui Zhilun; Yue Zhensing; Li Longtu

    2003-01-01

    Y-type hexaferrites series with Ba 2 Me 2 Fe 12 O 22 (Me=Zn, Co, Cu) has been prepared by the solid-state reaction method. Y-type polycrystalline hexaferrite powders were characterized by X-ray diffraction and the magnetic characteristics were investigated by vibrating samples magnetometer. Experimental results show that the substitution of Co for Zn leads to a decrease of saturation magnetization and an increase of magnetic anisotropy. At room temperature, saturation magnetization does not increase linearly as Zn content increases due to the effect of the thermal agitation. Saturation magnetization of the Zn-Cu Y-type ferrite exhibits the similar variational rule at room temperature. As Cu substitute for Co, the saturation magnetization and magnetic anisotropy all decrease. Cu modification can lower the single-phase formed temperature distinctly as the magnetic properties slightly debase

  7. Analysis of the magnetic properties nanoscale barium hexaferrite (BHF) prepared by milling and ultrasonic method

    International Nuclear Information System (INIS)

    Novizal; Edie, Sasito; Manawan, Mykel T.E.

    2016-01-01

    Barium hexaferrite (BHF) is well established material which widely used respectively as permanent magnets. In this research, we report our recent investigation on magnetic properties analysis of barium hexaferrite (BHF) compounds with a ratio of Fe/Ba: 11 prepared by a mechanical alloying process and high power ultrasonic destruction to promote the soft magnetic properties. The investigation carried out by Scanning Electron Microscope (SEM) shows the grain size between 500-1500 nm, it indicates that each grain is composed of several crystallites or polycrystalline. By mean of X-ray diff raction revealed the phase composition and the mean crystallite size <70 nm. The Characterization of the magnetic properties of the effects of downsizing the particle size of ∼ 200 nm to ∼ 50 nm by the ultasonik method provide saturation value of 0.35 T, remanent 0.24 T and the coercivity is 115 kA / m. (paper)

  8. Nanofiber production of poly (vinylidene fluoride) / hexaferrite, obtained by Blow Spinning Technique

    International Nuclear Information System (INIS)

    Dias, G.C.; Zadorosny, L.; Malmonge, J.A.; Malmonge, L.F.

    2014-01-01

    In this study, fibrous films of poly (vinylidene fluoride) - PVDF with barium hexaferrite particles were obtained by Solution Blow Spinning technique. In such technique, the polymer solution is injected through an inner nozzle which experiences the action of an accelerated flux of gas that drags and stretches the jet solution forming the nanofibers. The films were obtained from solutions of PVDF/DMF (30% w/v), which was incorporated into barium hexaferrite particles in proportions of 1, 3 and 5% (w / w). The results of the micrographs revealed the formation of a fibrous film with good dispersion of the particles. Xray analyzes showed the predominance of the β crystalline phase of PVDF. The increase of the amount of particles induces the appearance of a characteristic peak of PVDF. EDX measurements confirmed the presence of particles in the films. (author)

  9. The thermal stability range and magnetic properties of U-type hexaferrites

    International Nuclear Information System (INIS)

    Lisjak, Darja; Drofenik, Miha

    2004-01-01

    Single-phase polycrystalline U-hexaferrites with the composition Ba 4 A 2 Fe 36 O 60 (A=Co, Ni, Zn) were prepared by solid-state reaction synthesis employing high-energy milling or topotactic reaction and calcination at 1200-1300 deg. C. The Curie temperature and saturation magnetization of the samples were influenced by the composition, while the coercivity was more strongly influenced by the preparation conditions

  10. Microstructure and magnetic properties of Zr-Mn substituted M-type SrLa hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yujie; Wang, Fanhou; Shao, Juxiang; Huang, Duohui [Yibin University, Computational Physics Key Laboratory of Sichuan Province, School of Physics and Electronic Engineering, Yibin (China); Batoo, Khalid Mujasam [King Saud University, King Abdullah Institute for Nanotechnology, Riyadh (Saudi Arabia)

    2017-09-15

    In this study, we have synthesized the M-type SrLa hexaferrites with nominal compositions of Sr{sub 0.75}La{sub 0.25}Fe{sub 12.0-2x}(ZrMn){sub x}O{sub 19} (0.0 ≤ x ≤ 0.75) by the solid-state method techniques. The phase compositions of the samples were confirmed by X-ray diffraction analysis. X-ray diffraction analysis exhibits that all the synthesized M-type hexaferrite magnetic powders are in single magetoplumbite structure and no impurity phase is observed, and with the increase of ZrMn content (x), (107) and (114) peaks are broadened and the 2 θ values of (107) and (114) peaks shift towards lower angles. It is observed that lattice constants (c and a) increase with increasing ZrMn content (x) from 0.00 to 0.75. The morphology of the M-type hexaferrites was characterized by a field emission scanning electron microscopy (FE-SEM). FE-SEM images show that the M-type hexaferrite have formed hexagonal structures. Magnetization properties were measured at room temperature using a physical property measurement system-vibrating sample magnetometer. The saturation magnetization (M{sub s}), remanent magnetization (M{sub r}) and coercivity (H{sub c}) are calculated from magnetic hysteresis loops. M{sub s}, M{sub r} and M{sub r}/M{sub s} ratio first increase with increasing ZrMn content (x) from 0.00 to 0.15, and then decrease when ZrMn content (x) ≥0.15. H{sub c} decreases with the increase of ZrMn content (x) from 0.00 to 0.75. (orig.)

  11. Ce{sup 3+} incorporated structural and magnetic properties of M type barium hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Pawar, R.A. [Department of Physics, Arts, Commerce and Science College, Satral, MS (India); Desai, S.S.; Tamboli, Q.Y. [Materials Research Laboratory, Shrikrishna Mahavidyalaya, Gunjoti 413613, MS (India); Shirsath, Sagar E. [Spin Device Technology Center, Faculty of Engineering, Shinshu University, Nagano 380-8553 (Japan); Patange, S.M., E-mail: smpatange@rediffmail.com [Materials Research Laboratory, Shrikrishna Mahavidyalaya, Gunjoti 413613, MS (India)

    2015-03-15

    M type barium hexaferrites BaCe{sub x}Fe{sub 12−x}O{sub 19} (0≤x≤0.3) (BCFO) were synthesized by the sol–gel auto combination method. Optimum annealing temperature of hexagonal phase was determined by using the TGA analysis. The annealing temperature form the TGA is 1000 °C samples annealed 1000 °C for 5 h to produce M type hexaferrites. X-ray diffraction data run to full Prof Program (Winploter 2010) pattern indicate that samples are single phase hexagonal structure with space group P6{sub 3}/mmc. Lattice parameter ‘a’ and ‘c’ increase with increase in Ce content x. Results of field emission scanning electron microscope show that the grains are regular hexagonal platelets with sizes from 0.3 to 1.4 μm. It is observed that from M–H curve value of the saturation magnetization and coercivity decreases with increasing x. Curie temperature from magnetization with temperature plot is found to decrease with Ce{sup 3+} substitution x due to decreases in magnetic interaction. - Highlights: • Ce{sup 3+} substituted Ba hexaferrites. • Increased coercivity with Ce{sup 3+} substitution. • Decrease in saturation magnetization and Curie temperature.

  12. Effect of lanthanum substitution on dielectric relaxation, impedance response, conducting and magnetic properties of strontium hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Want, Basharat, E-mail: bawant@kashmiruniversity.ac.in; Bhat, Bilal Hamid; Ahmad, Bhat Zahoor

    2015-04-05

    Highlights: • The substitution of La affects the dielectric and magnetic properties of strontium hexaferrite. • The electric behaviour of the compound follows the Koop’s phenomenological theory. • The impedance study shows the role of grain boundaries to the electric properties of the compound. • The substitution of La to strontium hexaferrite reduces the resistive nature of grain boundaries. - Abstract: Lanthanum strontium hexaferrite Sr{sub 1−x}La{sub x}Fe{sub 12}O{sub 19} (x = 0, 0.08, 0.13 , 0.18) has been successfully synthesized by using citrate-precursor method and characterized by different techniques. The X-ray diffraction results revealed that the sample is crystalline in nature and is of single phase with the space group P63/mmc. The dielectric, conducting and impedance related studies have been carried out as a function of frequency and concentration of lanthanum in the frequency ranges of 20 Hz–3 MHz. Impedance studies were performed in the frequency domain to distinguish between bulk and grain boundary contributions of the material to the overall dielectric response. The electric response of the material was also modeled by an equivalent circuit and different circuit parameters were calculated. Magnetic characterization of the material was also performed and the effect of lanthanum concentration was studied. The hysteresis loop obtained from the magnetometer showed that with the increase of lanthanum concentration, the saturation magnetisation decreases while as coercivity increases.

  13. Synthesis and properties of nickel-doped nanocrystalline barium hexaferrite ceramic materials

    Science.gov (United States)

    Waqar, Moaz; Rafiq, Muhammad Asif; Mirza, Talha Ahmed; Khalid, Fazal Ahmad; Khaliq, Abdul; Anwar, Muhammad Sabieh; Saleem, Murtaza

    2018-04-01

    M-type barium hexaferrite ceramics have emerged as important materials both for technological and commercial applications. However, limited work has been reported regarding the investigation of nanocrystalline Ni-doped barium hexaferrites. In this study, nanocrystalline barium hexaferrite ceramics with the composition BaFe12- x Ni x O19 (where x = 0, 0.3 and 0.5) were synthesized by sol-gel method and characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, vibrating sample magnetometer and precision impedance analyzer. All the synthesized samples had single magnetoplumbite phase having space group P63/mmc showing the successful substitution of Ni in BaFe12O19 without the formation of any impurity phase. Average grain size of undoped samples was around 120 nm which increased slightly with the addition of Ni. Saturation magnetization ( M s) and remnant magnetization ( M r) increased with the addition of Ni, however, coercivity ( H c) decreased with the increase in Ni from x = 0 to x = 0.5. Real and imaginary parts of permittivity decreased with the increasing frequency and increased with Ni content. Dielectric loss and conductivity showed slight variation with the increase in Ni concentration.

  14. Analysis of the structure and Mössbauer study of the neodymium substitution in the Sr-hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Pérez-Juache, T.J. [Departamento de Ingeniería de Procesos e Hidráulica, Universidad Autónoma Metropolitana-Iztapalapa, A.P. 55-534, 09340 México D.F., México (Mexico); Guerrero, A.L., E-mail: azdlobo@gmail.com [Facultad de Ciencias, UASLP, Salvador Nava Martínez, s/n. Zona Universitaria, 78290 San Luis Potosí S.L.P., México (Mexico); Cabal-Velarde, J.G. [Instituto Tecnológico Superior de Irapuato, Carretera Irapuato-Silao Km. 12.5. Irapuato, Guanajuato, México (Mexico); Mirabal-García, M. [Instituto de Física, UASLP, Dr. Manuel Nava No. 6. Zona Universitaria, 78290 San Luis Potosí S.L.P., México (Mexico); Palomares-Sánchez, S.A. [Facultad de Ciencias, UASLP, Salvador Nava Martínez, s/n. Zona Universitaria, 78290 San Luis Potosí S.L.P., México (Mexico); Matutes-Aquino, J.A. [Centro de Investigación en Materiales Avanzados, Ave. Miguel de Cervantes 120, Complejo Industrial Chihuahua, 31109 Chihuahua, Ch. México, México (Mexico)

    2016-12-15

    This work reads on the obtainment of the strontium hexaferrite substituted with neodymium in its pure phase using the solid state reaction method. The solubility of neodymium on the strontium hexaferrite was investigated according with the formula Sr{sub 1−x}Nd{sub x}Fe{sub 12}O{sub 19}, for x=0.00, 0.05, 0.10, 0.15, 0.20 and 0.25. Results indicate that neodymium is soluble in the hexaferrite until x=0.15. In samples with higher neodymium content there are traces of secondary phases. Analysis of magnetic and structural properties was performed in function of the neodymium content, always in its solubility range. From the structural properties, it was observed that the addition of a little neodymium quantity in the Sr-hexaferrite causes an important reduction of the unit cell volume. Also, magnetic properties are strongly linked to the structural behavior, in this case a trend to reduce the magnetization of the samples was detected when neodymium content increased, which can be explained in terms of fluctuations of the superexchange coupling conducted by the neodymium interactions with the structure. Mössbauer analysis was carried out in order to analyze the effects of the neodymium substitution on the hyperfine parameters, as well as to confirm the preferential site of the neodymium substitution in the Sr-hexaferrite.

  15. Metal Nanocomposites

    DEFF Research Database (Denmark)

    Fischer, Søren Vang; Uthuppu, Basil; Jakobsen, Mogens Havsteen

    2014-01-01

    We have made SU-8 gold nanoparticle composites in two ways, ex situ and in situ, and found that in both methods nanoparticles embedded in the polymer retained their plasmonic properties. The in situ method has also been used to fabricate a silver nanocomposite which is electrically conductive. Th...

  16. clay nanocomposites

    Indian Academy of Sciences (India)

    The present work deals with the synthesis of specialty elastomer [fluoroelastomer and poly (styrene--ethylene-co-butylene--styrene (SEBS)]–clay nanocomposites and their structure–property relationship as elucidated from morphology studies by atomic force microscopy, transmission electron microscopy and X-ray ...

  17. Crystal growth of hexaferrite architecture for magnetoelectrically tunable microwave semiconductor integrated devices

    Science.gov (United States)

    Hu, Bolin

    Hexaferrites (i.e., hexagonal ferrites), discovered in 1950s, exist as any one of six crystallographic structural variants (i.e., M-, X-, Y-, W-, U-, and Z-type). Over the past six decades, the hexaferrites have received much attention owing to their important properties that lend use as permanent magnets, magnetic data storage materials, as well as components in electrical devices, particularly those operating at RF frequencies. Moreover, there has been increasing interest in hexaferrites for new fundamental and emerging applications. Among those, electronic components for mobile and wireless communications especially incorporated with semiconductor integrated circuits at microwave frequencies, electromagnetic wave absorbers for electromagnetic compatibility, random-access memory (RAM) and low observable technology, and as composite materials having low dimensions. However, of particular interest is the magnetoelectric (ME) effect discovered recently in the hexaferrites such as SrScxFe12-xO19 (SrScM), Ba2--xSrxZn 2Fe12O22 (Zn2Y), Sr4Co2Fe 36O60 (Co2U) and Sr3Co2Fe 24O41 (Co2Z), demonstrating ferroelectricity induced by the complex internal alignment of magnetic moments. Further, both Co 2Z and Co2U have revealed observable magnetoelectric effects at room temperature, representing a step toward practical applications using the ME effect. These materials hold great potential for applications, since strong magnetoelectric coupling allows switching of the FE polarization with a magnetic field (H) and vice versa. These features could lead to a new type of storage devices, such as an electric field-controlled magnetic memory. A nanoscale-driven crystal growth of magnetic hexaferrites was successfully demonstrated at low growth temperatures (25--40% lower than the temperatures required often for crystal growth). This outcome exhibits thermodynamic processes of crystal growth, allowing ease in fabrication of advanced multifunctional materials. Most importantly, the

  18. High coercivity Gd-substituted Ba hexaferrites, prepared by chemical coprecipitation

    Science.gov (United States)

    Litsardakis, G.; Manolakis, I.; Serletis, C.; Efthimiadis, K. G.

    2008-04-01

    A series of Gd-substituted Ba hexaferrites with nominal formula (Ba1-xGdx)Oṡ5.25 Fe2O3 (x=0-0.30) were prepared by the chemical coprecipitation method from nitrate precursors and heating at T =800-1200°C for 2h. The samples have been examined by x-ray diffraction, vibrating-sample magnetometer, and scanning electron microscopy methods. Gd substituted samples form single phase materials with the M-type hexaferrite structure at all heating temperatures, in the range of x ⩽0.10-0.20. The saturation magnetization (at 1.8T) varies slightly with x in most cases and, for x =0.05-0.10, it increases up to 66.7Am2/kg, exceeding the value of the unsubstituted hexaferrite. A strong enhancement of the coercivity is observed for all substituted samples, with maximum values Hc=457kA/m for the single-phase x =0.10 sample annealed at 1000°C and Hc=477kA/m for the x =0.25 sample annealed at 1100°C which contains Fe2O3 and GdFeO3 impurities. As the variation of coercivity with either substitution rate (x ) or annealing temperature is not monotonic, three different factors may account for the high coercivities that are obtained: (a) an inhibition of grain growth due to the presence of Gd, (b) a possible inherent effect on magnetocrystalline anisotropy, especially for single phase samples, and (c) a microstructural effect of secondary phases.

  19. Preparation and magnetic properties of the Sr-hexaferrite with foam structure

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, A.L., E-mail: azdlobo@gmail.com [Instituto de Física-UASLP, Álvaro Obregón 64, Centro. San Luis Potosí, S.L.P. (Mexico); Facultad de Ingeniería-UASLP, Álvaro Obregón 64, Centro. San Luis Potosí, S.L.P. (Mexico); Espericueta, D.L. [Facultad de Ingeniería-UASLP, Álvaro Obregón 64, Centro. San Luis Potosí, S.L.P. (Mexico); Facultad de Ciencias-UASLP, Álvaro Obregón 64, Centro. San Luis Potosí, S.L.P. (Mexico); Palomares-Sánchez, S.A. [Facultad de Ciencias-UASLP, Álvaro Obregón 64, Centro. San Luis Potosí, S.L.P. (Mexico); Elizalde-Galindo, J.T. [Instituto de Ingeniería y Tecnología-UACJ, Av. Plutarco Elías Calles 1210, Fovissste Chamizal, Ciudad Juárez, Chihuahua (Mexico); Watts, B.E [IMEM-CNR, Parco Area delle Scienze 37/A, 43124 Parma (Italy); Mirabal-García, M. [Instituto de Física-UASLP, Álvaro Obregón 64, Centro. San Luis Potosí, S.L.P. (Mexico)

    2016-12-01

    This work reports an optimal way to fabricate strontium hexaferrite with porous-reticulated structure using a variation of the replication technique and taking two different precursors, one obtained from the coprecipitation and the other from the ceramic method. Changes made to the original replication technique include the addition of Arabic gum as binder, and the addition of ethylene glycol to form the ceramic sludge. In addition, some parameters such as the relation between solid material and liquid phase, the quantity of binder and the heat treatment were varied to obtain high quality magnetic foams. Two polymeric sponges were used as patterns, one with average pore size of 300 μm diameter and the other with 1100 μm. The characterization of the samples included the analysis of the structure and phase purity, the magnetic properties, the remanence properties, magnetic interactions and the microstructural characteristics. Results indicate that both, the powder precursors and the polymeric pattern play an important role in the configuration of the foam structure and this configuration has an important influence on the dipolar interactions which tend to demagnetize the samples. In addition, it was analyzed the behavior between the minimum value of the δM curves and the hysteresis properties. - Highlights: • New way to obtain Sr-hexaferrite with foam structure and high magnetic performance. • Relation between pore structure and the magnetic properties in ceramic foams. • Analysis of magnetostatic interactions with the magnetism of Sr-hexaferrite foams. • Relation between microstructural characteristics and the magnetization of the foams.

  20. Preparation and magnetic properties of the Sr-hexaferrite with foam structure

    International Nuclear Information System (INIS)

    Guerrero, A.L.; Espericueta, D.L.; Palomares-Sánchez, S.A.; Elizalde-Galindo, J.T.; Watts, B.E; Mirabal-García, M.

    2016-01-01

    This work reports an optimal way to fabricate strontium hexaferrite with porous-reticulated structure using a variation of the replication technique and taking two different precursors, one obtained from the coprecipitation and the other from the ceramic method. Changes made to the original replication technique include the addition of Arabic gum as binder, and the addition of ethylene glycol to form the ceramic sludge. In addition, some parameters such as the relation between solid material and liquid phase, the quantity of binder and the heat treatment were varied to obtain high quality magnetic foams. Two polymeric sponges were used as patterns, one with average pore size of 300 μm diameter and the other with 1100 μm. The characterization of the samples included the analysis of the structure and phase purity, the magnetic properties, the remanence properties, magnetic interactions and the microstructural characteristics. Results indicate that both, the powder precursors and the polymeric pattern play an important role in the configuration of the foam structure and this configuration has an important influence on the dipolar interactions which tend to demagnetize the samples. In addition, it was analyzed the behavior between the minimum value of the δM curves and the hysteresis properties. - Highlights: • New way to obtain Sr-hexaferrite with foam structure and high magnetic performance. • Relation between pore structure and the magnetic properties in ceramic foams. • Analysis of magnetostatic interactions with the magnetism of Sr-hexaferrite foams. • Relation between microstructural characteristics and the magnetization of the foams.

  1. Effect of sintering conditions on the magnetic disaccommodation in barium M-type hexaferrites

    International Nuclear Information System (INIS)

    Hernandez-Gomez, Pablo; Torres, Carlos; Francisco, Carlos de; Munoz, Jose Maria; Alejos, Oscar; Iniguez, Jose Ignacio; Raposo, Victor; Montero, Oscar

    2006-01-01

    The relaxation of the initial magnetic permeability has been measured in polycrystalline hexaferrites with nominal composition BaO.6Fe 2 O 3 (i.e. M-type). The samples have been sintered at different temperatures in CO 2 atmosphere and with different manufacturing conditions. In temperature range between 80 and 500 K, the magnetic disaccommodation shows presence of different relaxation processes, depending on both the sintering temperature and sintering time. The analogies and differences between the results obtained are discussed in terms of similar phase formation and different crystallite size

  2. Magnetic and optical properties of Zn{sup 2+} ion substituted barium hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Baykal, A., E-mail: hbaykal@fatih.edu.tr [EYRA Textile Chemicals and Chemical Industry Trade Company, Saraçlar Industrial Zone, No: 3-12, 34490 İkitelli, İstanbul (Turkey); Auwal, I.A. [Department of Chemistry, Sule Lamido University, P.M.B 048, Kafin Hausa, Jigawa State (Nigeria); Güner, S. [Department of Physics, Fatih University, 34500 B.Çekmece, İstanbul (Turkey); Sözeri, H. [TÜBITAK – UME, National Metrology Institute, 41470 Gebze, Kocaeli (Turkey)

    2017-05-15

    Ba{sub 1−x}Zn{sub x}Fe{sub 12}O{sub 19} (0.0≤x≤0.3) hexaferrites were produced via sol-gel auto combustion technique. XRD patterns show that all the samples are single-phase M-type barium hexaferrite (BaM). Scanning electron microscopy (SEM) revealed that grains have a size range of 0.5–2 µm. The magnetic hysteresis (σ-H) loops revealed the ferromagnetic nature of NPs. The average crystallite sizes were calculated by applying Scherrer equation on the base of XRD powder patterns of all samples and found to be in the range of 16.78–48.34 nm. In particular, Ba{sub 1−x}Zn{sub x}Fe{sub 12}O{sub 19} (0.0≤x≤0.3) hexaferrites have suitable magnetic characteristics (saturation magnetization in a range of 63.00–67.70 emu/g and coercive field in a range of 822–1275 Oe) for magnetic recording and permanent magnets. Effective crystalline anisotropy constants (K{sub eff}) are between 4.20×10{sup 5} and 4.84×10{sup 5} Erg/g. Magnetic moment increased by the substitution of non-magnetic Zn{sup 2+} ions. The anisotropy field (H{sub a}) or intrinsic coercivity values above 13255 Oe reveals that all samples are magnetically hard materials. Tauc plots were drawn to specify the direct optical energy band gap (E{sub g}) of NPs. The E{sub g} values are in a narrow range between 1.69 eV and 1.76 eV. - Highlights: • Diamagnetic Zn{sup 2+} ionsubstitution on magnetic and optical properties of barium hexaferrite has been investigated. • All products are ferromagnetic. • The grain sizes are much larger than the critical dimension of 431 nm to exhibit single-domain nature.

  3. Influence of stoichiometry on the magnetic disaccommodation in M-type Sr hexaferrites

    International Nuclear Information System (INIS)

    Hernandez-Gomez, Pablo; Torres, Carlos; Francisco, Carlos de; Munoz, J.M.; Alejos, Oscar; Iniguez, J.I.; Raposo, Victor

    2004-01-01

    The relaxation of the initial permeability has been measured in polycrystalline Sr hexaferrites with the initial composition SrO·nFe 2 O 3 (n=5.7, 6), prepared by means of standard ceramic techniques in air as well as CO 2 sintering atmospheres. The isochronal disaccommodation spectra show the presence of different relaxation processes, depending on both the sintering atmosphere and especially the initial composition, and associated to ionic reorientations of ferrous cations and lattice vacancies in the different metallic sites within the spinel (S) and hexagonal (R) blocks of the close packed lattice

  4. Improvement of the performance of microwave X band absorbers based on pure and doped Ba-hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Seyyed Afghahi, Seyyed Salman [Department of Materials Science and Engineering, Imam Hossein University, Tehran (Iran, Islamic Republic of); Jafarian, Mojtaba, E-mail: m.jafarian@srbiau.ac.ir [Young Researchers and Elite Club, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Salehi, Mohsen [Young Researchers and Elite Club, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Atassi, Yomen [Department of Applied Physics, Higher Institute for Applied Sciences and Technology, Damascus (Syrian Arab Republic)

    2017-01-01

    Optimum Fe/Ba mole ratio is determined in doped Ba-hexaferrite prepared via mechanical activation. X-ray diffractometer (XRD), scanning electron microscope (SEM), vibrating sample magnetometer (VSM) and vector network analyzer are used to analyze phases, structures, electromagnetic and microwave absorption properties. The mole ratio of Fe/Ba=10 is detected to be optimum for doping and synthesizing the Ba-hexaferrite. In order to achieve high absorption in X band the ions of Zr{sup 4+}–Sn{sup 4+}–Ti{sup 4+}–M{sup 2+} (M=Mg{sup 2+}, Zn{sup 2+}, Cu{sup 2+}, Co{sup 2+}) are used as dopants. The results indicate the formation of single phase Ba-hexaferrite in either pure or doped compounds without any non-magnetic intermediate phases and with spherical and hexagonal morphologies respectively for the pure and doped ferrite. It is found out that BaCo{sub 2}Zr(SnTi){sub 0.5}Fe{sub 8}O{sub 19} compound has the maximum saturation magnetization (49.80 emu/g). Also the composite of BaCo{sub 2}Zr(SnTi){sub 0.5}Fe{sub 8}O{sub 19} 50 wt% in epoxy resin exhibits a minimum reflection loss of −29 dB at 12.2 GHz with 2.6 GHz bandwidth. - Highlights: • Optimum Fe/Ba mole ratio is determined in doped Ba-hexaferrite. • Formation of a single phase M-hexaferrite, pure or doped when Fe/Ba=10. • Preparation of microwave absorber of BaCo{sub 2}Zr(SnTi){sub 0.5}Fe{sub 8}O{sub 19}/epoxy resin, 50 wt%. • The absorber exhibits a minimum RL of −29 dB at 12.2 GHz with 2.6 GHz bandwidth.

  5. Role of Tb–Mn substitution on the magnetic properties of Y-type hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Irshad, E-mail: irshadalibzu@gmail.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Islam, M.U. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Ashiq, Muhammad Naeem, E-mail: naeemashiqqau@yahoo.com [Institute of Chemical Sciences, Bahauddin Zakariya University, Multan 60800 (Pakistan); Asif Iqbal, M. [National University of Sciences and Technology, EME College, Islamabad (Pakistan); Karamat, Nazia [Institute of Chemical Sciences, Bahauddin Zakariya University, Multan 60800 (Pakistan); Awan, M.S. [Center for Micro and Nano Devices, Department of Physics, COMSAT Institute of Information Technology, Islamabad (Pakistan); Naseem, Shahzad [Centre for Solid State Physics, University of the Punjab, Lahore 54560 (Pakistan)

    2014-06-25

    Graphical abstract: In-plane MH-loop of Tb–Mn substituted Co{sub 2}Sr{sub 2}Fe{sub 12}O{sub 22}. - Highlights: • The magnetic properties changes with increasing substitution level. • The shape of grains is plate like useful for microwave devices. • The samples can be used in perpendicular recording media (PRM) due to their high value of coercivity. - Abstract: A series of (Tb–Mn) doped Sr{sub 2}Co{sub (2−x)}Mn{sub x}Tb{sub y}Fe{sub (12−y)}O{sub 22} (x = 0.0–1, Y = 0.0–0.1) Y-type hexaferrite were synthesized by the microemulsion method. The effect of doping of manganese at the tetrahedral site, and terbium at octahedral site, has been studied. It was observed that changes in magnetic properties such as saturation magnetization, coercivity, remanence and magnetic moment due to the cationic stoichiometry and their occupancy in the specific sites. The energy-dispersive X-ray fluorescence analysis was used to confirm the concentration of the elements. Scanning electron micrograph of the samples showed that grains are of plate like shape which is quite encouraging for their use in microwave devices and in perpendicular recording media (PRM) due to their high value of coercivity, 3200 Oe comparable to M-type and W-type hexaferrites hard magnetic materials.

  6. Effects of Gd substitution on the structural and magnetic properties of strontium hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Litsardakis, G. [Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece)]. E-mail: Lits@eng.auth.gr; Manolakis, I. [Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece); Serletis, C. [Department of Physics, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece); Efthimiadis, K.G. [Department of Physics, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece)

    2007-09-15

    The effect of Gd substitution in M-type strontium hexaferrites has been examined in two series of samples, (Sr{sub 1-x}Gd{sub x})O.5.25Fe{sub 2}O{sub 3} and Sr{sub 1-x}Gd{sub x}Fe{sub 12-x}Co{sub x}O{sub 19}, both prepared by the ceramic method, where x=0-0.40. The samples have been characterized by XRD, VSM and SEM-EDAX techniques. All substituted samples present primarily the hexaferrite structure. Sample (Sr{sub 0.95}Gd{sub x0.05})O.5.25Fe{sub 2}O{sub 3} is single phase. Formation of impurity phases is affected by stoichiometry and presence of Co. In Sr-Gd samples, coercivity showed a maximum value of 305kA/m (3.8kOe) for x=0.20, while remanence and saturation magnetization did not decrease. Coercivity and magnetization in the Sr-Gd-Co series decreased steadily with substitution degree.

  7. Effect of Co substitution on absorption properties of SrCoxFe12-xO19 hexagonal ferrites based nanocomposites in X-band

    Science.gov (United States)

    Chakraborty, Soma; Bhattacharyya, Nidhi Saxena; Bhattacharyya, Satyajib

    2017-12-01

    Cobalt doped M-type strontium hexaferrite nanoparticles (SrCoxFe12-xO19, x = 0.2-1.2) is synthesized and used as inclusions in Linear Low Density Polyethylene (LLDPE) matrix for developing nano-composites with 60 wt% of these nanoparticles. Absorption performance of the developed nano-composites is evaluated in the X-band. The thickness optimization is carried out for obtaining maximum reflection loss by using the transmission line model (TLM), with measured values of permittivity and permeability of the composite. The best reflection loss is observed experimentally for x = 0.8 with an absorber thickness of 3 mm for which a wide -10 dB bandwidth covering almost the entire X-band is obtained. The composites are light weight and not affected by exposure to water.

  8. A comparative study on the magnetic and electrical properties of MFe12O19 (M=Ba and Sr)/BiFeO3 nanocomposites

    Science.gov (United States)

    Ahmed, M. A.; Mansour, S. F.; Ismael, H.

    2015-03-01

    M-type hexaferrite (MFe12O19), M=Ba or Sr nanoparticles with hexagonal crystal structure have been successfully synthesized by a citrate auto-combustion method. BiFeO3 (BFO) was prepared by the flash auto-combustion technique. Different nanocomposites were prepared according to the formula [(1-X) MFe12O19+XBiFeO3; M=Ba or Sr, X=0.3, 0.4, 0.5 and 0.6]. The structure and morphology of the obtained nanocomposites have been determined by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). From the results, it is observed that the value of saturation magnetization decreases with increasing BFO content, which was mainly due to the contribution of the volume of the weak-magnetic BFO to the total sample volume.

  9. Quasi-epitaxial barium hexaferrite thin films prepared by a topotactic reactive diffusion process

    Science.gov (United States)

    Meng, Siqin; Yue, Zhenxing; Zhang, Xiaozhi; Li, Longtu

    2014-01-01

    Quasi-epitaxial barium hexaferrite thin films (BaM) with crystallographic c-axis parallel to film normal were prepared through a topotactic reactive diffusion process using two-step solution deposition on c-plane sapphire. The two-step spin coating process involves preparing an epitaxial hematite film, coating the film with barium precursor solution and thermal annealing. The crystal orientation and magnetic anisotropy of BaM thin films were investigated by X-ray diffraction analysis, SEM observation and magnetic measurements. Hysteresis loops showed good magnetic anisotropy and high remanence ratio (RR) Mr/Ms = 0.97. The films fabricated by two-step spin coating process displayed wider rocking curve width but better magnetic anisotropy than one-step spin coating. The possible mechanism of this discrepancy is discussed in this paper.

  10. Quasi-epitaxial barium hexaferrite thin films prepared by a topotactic reactive diffusion process

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Siqin; Yue, Zhenxing, E-mail: yuezhx@tsinghua.edu.cn; Zhang, Xiaozhi; Li, Longtu

    2014-01-30

    Quasi-epitaxial barium hexaferrite thin films (BaM) with crystallographic c-axis parallel to film normal were prepared through a topotactic reactive diffusion process using two-step solution deposition on c-plane sapphire. The two-step spin coating process involves preparing an epitaxial hematite film, coating the film with barium precursor solution and thermal annealing. The crystal orientation and magnetic anisotropy of BaM thin films were investigated by X-ray diffraction analysis, SEM observation and magnetic measurements. Hysteresis loops showed good magnetic anisotropy and high remanence ratio (RR) Mr/Ms = 0.97. The films fabricated by two-step spin coating process displayed wider rocking curve width but better magnetic anisotropy than one-step spin coating. The possible mechanism of this discrepancy is discussed in this paper.

  11. Growth of Ba-hexaferrite films on single crystal 6-H SiC

    International Nuclear Information System (INIS)

    Chen Zhoahui; Yang, Aria; Yoon, S.D.; Ziemer, Katherine; Vittoria, Carmine; Harris, V.G.

    2006-01-01

    Barium hexaferrite films have been processed by pulsed laser deposition on single crystal 6-H silicon carbide substrates. Atomic force microscopy images show hexagonal crystals (∼0.5μm in diameter) oriented with the c-axis perpendicular to the film plane. X-ray θ-2θ diffraction measurements indicate a strong (0,0,2n) alignment of crystallites. The magnetization for low-pressure deposition (20mTorr) is comparable to bulk values (4πM s ∼4320G). The loop squareness, important for self-bias microwave device applications, increases with oxygen pressure reaching a maximum value of 70%. This marks the first growth of a microwave ferrite on SiC substrates and offers a new approach in the design and development of μ-wave and mm-wave monolithic integrated circuits. c integrated circuits

  12. The magnetic properties of strontium hexaferrites with La-Cu substitution prepared by SHS method

    International Nuclear Information System (INIS)

    Qiao Liang; You Lishun; Zheng Jingwu; Jiang Liqiang; Sheng Jiawei

    2007-01-01

    La-Cu substituted strontium hexaferrites with the chemical composition of Sr 1- x La x Fe 12- x Cu x O 19 were prepared by self-propagating high-temperature synthesis. The effects of La-Cu substitution on the microstructure and magnetic properties of Sr-ferrites were studied. The XRD results show that all the samples are single SrM-type phase for x 1- x La x Fe 12- x Cu x O 19 are remarkably improved for x 2+ by La 3+ in the Sr-layer makes the Cu 2+ preferably substitutes the Fe 3+ in 4f 2 sites is predicted to be associated with the improvement of the magnetic properties of La-Cu substituted samples

  13. Electromagnetic behavior of radar absorbing materials based on Ca hexaferrite modified with Co-Ti ions and doped with La

    Directory of Open Access Journals (Sweden)

    Valdirene Aparecida da Silva

    2009-06-01

    Full Text Available Radar Absorbing Materials (RAM are compounds that absorb incidental electromagnetic radiation in tuned frequencies and dissipate it as heat. Its preparation involves the adequate processing of polymeric matrices filled with compounds that act as radar absorbing centers in the microwave range. This work shows the electromagnetic evaluation of RAM based on CoTi and La doped Ca hexaferrite. Vibrating Sample Magnetization analyses show that ion substitution promoted low values for the parameters of saturation magnetization (123.65 Am2/kg and coercive field (0.07 T indicating ferrite softening. RAM samples obtained using different hexaferrite concentrations (40-80 per cent, w/w show variations in complex permeability and permittivity parameters and also in the performance of incidental radiation attenuation. Microwave attenuation values between 40 and 98 per cent were obtained.

  14. Tailoring magnetic properties of self-biased hexaferrites using an alternative copolymer of isobutylene and maleic anhydride

    Science.gov (United States)

    Wu, Chuanjian; Yu, Zhong; Sokolov, Alexander S.; Yu, Chengju; Sun, Ke; Jiang, Xiaona; Lan, Zhongwen; Harris, Vincent G.

    2018-05-01

    Discussed is a novel self-biased hexaferrite gelling system based on a nontoxic and water-soluble copolymer of isobutylene and maleic anhydride. This copolymer simultaneously acts as a dispersant and gelling agent, and recently received much attention from the ceramics community. Herein its effects on the rheological conditions throughout magnetic-field pressing, and consequently, orientation, density and magnetic properties of textured hexaferrites were investigated. Ka-band FMR linewidths were measured, and the crystalline anisotropy and porosity induced linewidth broadening were estimated according to Schlömann's theory. The copolymer allowed to reduce the friction between micron-sized magnetic particulates, resulting in higher density and degree of crystalline orientation, and lower FMR linewidth.

  15. Electrochromic nanocomposite films

    Science.gov (United States)

    Milliron, Delia; Llordes, Anna; Buonsanti, Raffaella; Garcia, Guillermo

    2018-04-10

    The present invention provides an electrochromic nanocomposite film. In an exemplary embodiment, the electrochromic nanocomposite film, includes (1) a solid matrix of oxide based material and (2) transparent conducting oxide (TCO) nanostructures embedded in the matrix. In a further embodiment, the electrochromic nanocomposite film farther includes a substrate upon which the matrix is deposited. The present invention also provides a method of preparing an electrochromic nanocomposite film.

  16. Enhancement of structural and magnetic properties of M-type hexaferrite permanent magnet based on synthesis temperature

    Science.gov (United States)

    Anjum, Safia; Sehar, Fatima; Mustafa, Zeeshan; Awan, M. S.

    2018-01-01

    The main purpose of this research work is to develop the single domain magnetic particles of M-type barium hexaferrite (BaFe12O19) using oxide precursors employing conventional powder metallurgy technique. The phase formation and magnetic performance of the powders and magnets will be optimized by adjusting calcination and sintering temperatures. The synthesis of M-type barium hexaferrite was carried out in two sections. A series of four samples have been prepared by initial wet mixed powders calcined at different temperatures, i.e., 750, 850, 950 and 1050 °C. On the basis of structural analysis, the sample calcined at 950 °C has been selected and further divided into four parts to sintered them at 1100, 1150, 1200 and 1250 °C. The structural measurements depict the confirmation of M-type barium hexaferrite structure. SEM micrographs show the hexagonal-shaped grains. The abrupt decrease in coercivity for the sample sintered at 1250 °C has been seen which may be due to high sintering temperature, at which the particles have multi-domain properties.

  17. Magnetic properties of co-precipitated hexaferrite powders with Sm-Co substitutions optimized with the molten flux method

    Science.gov (United States)

    Serletis, C.; Litsardakis, G.; Pavlidou, E.; Efthimiadis, K. G.

    2017-11-01

    In this work, using the chemical coprecipitation method, Sr1-xSmxFe12-xCoxO19 (x = 0, 0.1, 0.2) hexaferrite powders were prepared. Major magnetization loops were recorded at room temperature in order to determine the correct calcination temperature for optimum hard magnetic properties. It is found that a small degree of substitution increases substantially the coercive field. Also, the use of the molten flux calcination method increases the remanent magnetization. SEM/EDXS and XRD measurements were performed at the calcined powders: the results show that a single hexaferrite phase is formed and that the substituted powders consist of an assembly of grains with a mean diameter of 40 nm. Measurements of minor magnetization loops and of the temperature and time dependence of the magnetization confirm that the powders consist of a non-oriented single domain magnetic particles assembly. The results indicate that Sm could be a viable replacement for La in the manufacturing of hexaferrites with a high-energy product.

  18. A comparison of the influence of different dopants on the radar-absorbing properties of barium hexaferrite

    International Nuclear Information System (INIS)

    Jones, M.; Suder, M.M.; Edge, A.J.J.; Stewart, G.A.; Hutchison, W.D.; Amiet, A.; Jewsbury, P.

    2004-01-01

    Full text: The ferromagnetic resonance of barium hexaferrite is at approximately 48 GHz, which sits well above the frequency bands employed by most radar systems. However, certain elements (or combinations of elements), when doped into the iron sub-lattice, have been observed to weaken the system's uniaxial magnetocrystalline anisotropy and thereby lower the ferromagnetic resonance frequency. This contribution presents a survey of ferromagnetic resonance frequencies published in the literature, as well as resonance frequencies that we have converted from published magnetic characterisations of the magnetic anisotropy. In several cases we have confirmed the reliability of such converted values, and new data will be presented for (Co 1/2 Zr 1/2 )- and (Co 1/2 Mo 1/2 )-doped barium hexaferrite. Our specimen materials were prepared by solid state reaction, and characterised using x-ray powder diffraction and 57 Fe Moessbauer spectroscopy. The electromagnetic response characteristics were recorded with a microwave network analyser, using either a co-axial specimen (0 - 18 GHz) or a larger, planar tile specimen (0 - 40 GHz). An ideal radar absorbing material would require just a small concentration of an inexpensive dopant to lower the ferromagnetic resonance frequency into the 0 - 2 GHz band that is typical of long-range radars. The likelihood of finding such a doped barium hexaferrite system will be discussed

  19. Crystal structure refinement, dielectric and magnetic properties of Ca/Pb substituted SrFe{sub 12}O{sub 19} hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Hooda, Ashima [Department of Physics, Deenbandhu Chhotu Ram University of Science and Technology, Murthal 131039, Haryana (India); Sanghi, Sujata, E-mail: sutkash@yahoo.com [Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar 125001, Haryana (India); Agarwal, Ashish [Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar 125001, Haryana (India); Dahiya, Reetu [Department of Physics, Hindu Girls College, Sonepat 131001, Haryana (India)

    2015-08-01

    SrFe{sub 12}O{sub 19} (SFO), Sr{sub 0.5}Ca{sub 0.5}Fe{sub 12}O{sub 19} (SCFO) and Sr{sub 0.5}Pb{sub 0.5}Fe{sub 12}O{sub 19} (SPFO) hexaferrites have been synthesized by a conventional solid state reaction technique. Powder X-ray diffraction and Rietveld refinement confirm the presence of M-type hexagonal phase in prepared samples. However in SCFO, secondary phase was also present with main phase. Analysis of Nyquist's plots of SFO hexaferrite revealed the contribution of many electrically active regions corresponding to bulk mechanism, distribution of grain boundaries and electrode processes also. Both conductivity and electric modulus formalisms have been employed to study the relaxation dynamics of charge carriers. A perfect overlapping of the normalized plots of modulus isotherms on a single ‘super curve’ for all the studied temperatures reveals a temperature independence of dynamic processes involved in conduction and for relaxation. In SPFO sample coercivity is reduced effectively but accompanied with increase in magnetization, which is requirement for hexaferrites to be used as magnetic recording media. - Highlights: • Samples have hexagonal phase with space group P6{sub 3}/mmc. • SPFO hexaferrite may be used for microwave devices. • SPFO hexaferrite may be used for magnetic recording media.

  20. Investigation on structural properties of M-type strontium hexaferrite synthesized in presence of neem and aloe-vera plant leaves extract

    Science.gov (United States)

    Solanki, Neha; Jotania, Rajshree B.

    2017-05-01

    M-type strontium hexaferrite powder samples were synthesized using a green synthesis route with and without presence of Aloe vera and Neem leaves extract. The dry brownish precursors of strontium hexaferrite were recovered from a mixed solution of metal salts and leaves extract, heated at 100 °C. The obtained precursors were pre-heated at 500 °C for 4 hrs. followed by final heating at 950 °C for 4 hrs. in a muffle furnace to obtain SrFe12O19 hexaferrite powder. The obtained SrFe12O19 hexaferrite powder samples characterized at room temperature in order to check phase purity and structural properties. XRD analysis confirms that samples prepared without and with Aloe vera leaves extract (heated at 950 °C for 4 hrs.) show formation of α-Fe2O3 and M-phase; while the sample prepared in presence of Neem leaves extract (heated at 950 °C for 4 hrs.) show formation of mono phase of strontium hexaferrite. Lattice parameter (a) and cell volume (V) are found to increase in the samples prepared in presence of Aloe vera and Neem leaves extract.

  1. Origin of absorption peaks in reflection loss spectrum in Ku- frequency band of Co-Zr substituted strontium hexaferrites prepared using sucrose precursor

    Energy Technology Data Exchange (ETDEWEB)

    Narang, Sukhleen Bindra, E-mail: sukhleen2@yahoo.com [Department of Electronics Technology, Guru Nanak Dev University, Amritsar (India); Pubby, Kunal, E-mail: kunalpubby02@gmail.com [Department of Electronics Technology, Guru Nanak Dev University, Amritsar (India); Chawla, S.K., E-mail: sschawla118@gmail.com [Department of Chemistry, Centre for Advanced Studies-I, Guru Nanak Dev University, Amritsar (India); Kaur, Prabhjyot, E-mail: prabhjyot.2525@gmail.com [Department of Chemistry, Centre for Advanced Studies-I, Guru Nanak Dev University, Amritsar (India)

    2017-03-15

    This study presents the detailed explanation of the factors, contributing towards the absorption peaks in reflection loss spectrum of hexaferrites. Cobalt-Zirconium substituted strontium hexaferrites, synthesized using sucrose precursor sol-gel technique, were analyzed in 12.4–18 GHz frequency range. The concepts of impedance matching through quarter wavelength condition, complex thickness, dielectric phase angle and attenuation constant have been used to determine the location as well as intensity of absorption peaks. This study also demonstrates the potential application of three compositions of this series with doping content (x)==0.0, 0.6 and 0.8 as an effective microwave absorbers in Ku-frequency band. - Highlights: • EM analysis of Sr Hexaferrites in Ku-band. • Factors towards absorption peak intensity & location.

  2. Multifunctional Polymer/Inorganic Nanocomposites

    National Research Council Canada - National Science Library

    Manias, E

    2003-01-01

    ... in multifunctional nanocomposite materials. Understanding the structure/property relations in polymer/clay nanocomposites is of great importance in designing materials with desired sets of properties...

  3. Magnetic nanocomposite sensor

    KAUST Repository

    Alfadhel, Ahmed

    2016-05-06

    A magnetic nanocomposite device is described herein for a wide range of sensing applications. The device utilizes the permanent magnetic behavior of the nanowires to allow operation without the application of an additional magnetic field to magnetize the nanowires, which simplifies miniaturization and integration into microsystems. In5 addition, the nanocomposite benefits from the high elasticity and easy patterning of the polymer-based material, leading to a corrosion-resistant, flexible material that can be used to realize extreme sensitivity. In combination with magnetic sensor elements patterned underneath the nanocomposite, the nanocomposite device realizes highly sensitive and power efficient flexible artificial cilia sensors for flow measurement or tactile sensing.

  4. Volumetric composition of nanocomposites

    DEFF Research Database (Denmark)

    Madsen, Bo; Lilholt, Hans; Mannila, Juha

    2015-01-01

    is presented, using cellulose/epoxy and aluminosilicate/polylactate nanocomposites as case materials. The buoyancy method is used for the accurate measurements of materials density. The accuracy of the method is determined to be high, allowing the measured nanocomposite densities to be reported with 5...... significant figures. The plotting of the measured nanocomposite density as a function of the nanofibre weight content is shown to be a first good approach of assessing the porosity content of the materials. The known gravimetric composition of the nanocomposites is converted into a volumetric composition...

  5. Site occupancy and magnetic properties of Al-substituted M-type strontium hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Dixit, Vivek; Nandadasa, Chandani N.; Kim, Seong-Gon, E-mail: kimsg@ccs.msstate.edu [Department of Physics and Astronomy, Mississippi State University, Mississippi State, Mississippi 39762 (United States); Center for Computational Sciences, Mississippi State University, Mississippi State, Mississippi 39762 (United States); Kim, Sungho [Center for Computational Sciences, Mississippi State University, Mississippi State, Mississippi 39762 (United States); Park, Jihoon; Hong, Yang-Ki [Department of Electrical and Computer Engineering and MINT Center, The University of Alabama, Tuscaloosa, Alabama 35487 (United States); Liyanage, Laalitha S. I. [Department of Physics, University of North Texas, Denton, Texas 76203 (United States); Moitra, Amitava [Thematic Unit of Excellence on Computational Materials Science, S.N. Bose National Centre for Basic Sciences, Sector-III, Block-JD, Salt Lake, Kolkata-700098 (India)

    2015-06-28

    We use first-principles total-energy calculations based on density functional theory to study the site occupancy and magnetic properties of Al-substituted M-type strontium hexaferrite SrFe{sub 12−x}Al{sub x}O{sub 19} with x = 0.5 and x = 1.0. We find that the non-magnetic Al{sup 3+} ions preferentially replace Fe{sup 3+} ions at two of the majority spin sites, 2a and 12k, eliminating their positive contribution to the total magnetization causing the saturation magnetization M{sub s} to be reduced as Al concentration x is increased. Our formation probability analysis further provides the explanation for increased magnetic anisotropy field when the fraction of Al is increased. Although Al{sup 3+} ions preferentially occupy the 2a sites at a low temperature, the occupation probability of the 12k site increases with the rise of the temperature. At a typical annealing temperature (>700 °C) Al{sup 3+} ions are much more likely to occupy the 12k site than the 2a site. Although this causes the magnetocrystalline anisotropy K{sub 1} to be reduced slightly, the reduction in M{sub s} is much more significant. Their combined effect causes the anisotropy field H{sub a} to increase as the fraction of Al is increased, consistent with recent experimental measurements.

  6. Magnetic and Dielectric Investigations of Mn-Doped Ba Hexaferrite Nanoparticles by Hydrothermal Approach

    Science.gov (United States)

    Adeela, N.; Khan, U.; Iqbal, M.; Riaz, S.; Ali, H.; Maaz, K.; Naseem, S.

    2016-11-01

    A hydrothermal method followed by heat treatment was used to synthesize Mn-substituted Ba2Co2- x Mn x Fe12O22 nanoparticles with a nominal chemical composition of 0 ≤ x < 1 and step gap of 0.3. In this study, the effect of Mn substitution on Co2Y-type barium hexaferrite is investigated after employing x-ray diffraction for crystal structure, field emission scanning electron microscopy for morphology, energy dispersive analysis of x-ray spectroscopy for elemental composition, Fourier transform infrared spectroscopy to confirm bond modes, and vibrating sample magnetometry for magnetic measurements. It was found that the sample at x = 0.9 is of particular interest due to its large coercivity and anisotropy. Later on, for x = 0.9, temperature-dependent magnetic analyses including hysteresis loops, zero-field-cooled, and field-cooled at a particular field of 100 Oe were performed. The decreasing trend in saturation magnetization with increase in temperature was estimated. On the other hand, first an increase and then decrease in coercivity values were observed. These loops also revealed dependence of coercivity on magneto-crystalline anisotropy and average crystallite size of nanoparticles. Dielectric measurements at x = 0.9 make it suitable for high frequency applications.

  7. Structural and magnetic properties of conventional and microwave treated Ni–Zr doped barium strontium hexaferrite

    International Nuclear Information System (INIS)

    Kanagesan, S.; Jesurani, S.; Velmurugan, R.; Prabu, S.; Kalaivani, T.

    2012-01-01

    Highlights: ► Saturation magnetization increases whereas the coercivity decreases. ► The transition from hard phase to soft phase. ► Therefore, it is used for high-density magnetic recording applications. -- Abstract: M-type hexaferrites of component B 0.5 Sr 0.5 Fe 12−2x Ni x Zr x O 19 were investigated. The XRD patterns show single phase of the magnetoplumbite barium strontium ferrite and no other phases were present. Significant increase in line broadening of the XRD patterns was observed indicating a decrease of grain size. The samples exhibit well defined crystallization; all of them are hexagonal platelet grains. As the substitution level increased x = 0.2–0.8 mol%, the grains are agglomerated and the average diameter increased. The H c decreases remarkably with increasing Ni and Zr ions content. It was found that the particle size could be effectively decreased and coercivity H c could easily be controlled by varying the concentration (x) without significantly decreasing saturation magnetization. In particular, Ba 0.5 Sr 0.5 Fe 12−2x Ni x Zr x O 19 with x = 0.2, 0.4, 0.6, 0.8 mol% has suitable magnetic characteristics with particle size small enough for high-density magnetic recording applications.

  8. Preparation and investigation of structural, magnetic and microwave absorption properties of cerium doped barium hexaferrite

    Directory of Open Access Journals (Sweden)

    P Kameli

    2015-01-01

    Full Text Available In this study the structure, magnetic and microwave absorption properties of cerium (Ce doped barium hexaferrite with general formulae BaCexFe12-xO19 (x=0.0, 0.05, 0.1, 0.15, 0.2 have been investigated. These samples have been prepared by sol- gel method. Influence of replacing Fe+3 ion by rare- earth Ce+3 ion on the structural, magnetic and microwave absorption properties have been investigated by X- ray diffraction (XRD, Fourier transform infrared (FT-IR, Vibrating sample magnetometer (VSM and vector network analyzer (VNA. X-ray diffraction analysis indicated that the samples are of single phase with space group p63/mmc. The magnetic properties of samples indicated that with the Ce doping the saturation magnetization show no regular behavior. Moreover, coercivity (Hc first decreased and reached to the minimum value for x=0.1 sample and then increased with Ce content increasing. Also, measurement of electromagnetic wave absorption in X and Ku frequency bands indicated that the maximum of reflection loss obtained for x=0.15 sample. Moreover, result indicated that absorption peak shifted toward a lower frequency when thickness was increased.

  9. Pressure-induced Polarization Reversal in Z-type Hexaferrite Single Crystal

    Science.gov (United States)

    Jeon, Byung-Gu; Chun, Sae Hwan; Kim, Kee Hoon

    2012-02-01

    Multiferroic materials with a gigantic magnetoelectric (ME) coupling at room temperature have been searched for applications to novel devices. Recently, large direct and converse ME effects were realized at room temperature in the so-called Z-type hexaferrite (Ba,Sr)3Co2Fe24O41 single crystals [1,2]. To obtain a new control parameter for realizing a sensitive ME tuning, we studied ME properties of the crystals under uniaxial pressure. Upon applying a tiny uniaxial pressure of about 0.6 GPa, magnetic field-driven electric polarization reversal and anomaly in a M-H loop start to appear at 10 K and gradually disappear at higher temperature above 130 K. By comparing those results with longitudinal magnetostriction at ambient pressure, we propose the pressure-dependent variations of transverse conical spin configuration as well as its domain structure under small magnetic field bias, and point out the possibility of having two different physical origins of the ME coupling in this system. [1] Y. Kitagawa et al., Nat. Mater. 9, 797 (2010) [2] S. H. Chun et al., submitted.

  10. Simultaneous effect of crystal lattice and non magnetic substitution on magnetic properties of barium hexaferrite

    Science.gov (United States)

    Kumar, Sunil; Supriya, Sweety; Pradhan, Lagen Kumar; Pandey, Rabichandra; Kar, Manoranjan

    2018-05-01

    The aluminium doped barium hexaferrite BaFe12-xAlxO19 with x =0.0, 1.0, 2.0, 4.0 and 6.0 have been synthesized by the sol-gel method to modify the magnetic properties for technological applications. The crystal structure and phase purity of all the samples have been explored by employing the X-ray diffraction (XRD) technique. It confirms that the sample is nanocrystalline, hexagonal symmetry and all the intense peaks could be indexed to the P63/mmc space group. The obtained lattice parameters from the XRD analysis decrease with the increase in Al3+ content in the samples. The microstructural morphology and particle sizes of all samples were studied by using the Field Emission Scanning Electron Microscopy (FESEM-Hitachi-S4800) technique. The magnetic hysteresis (M-H) loops measurement has been carried out at room temperature by employing the vibrating sample magnetometer (VSM) over a field range of +20 kOe to -20 kOe. The magnetic hysteresis (M-H) loops revealed the ferromagnetic (hard magnetic materials) nature of the samples and, analyzed by using the Law of Approach to Saturation.

  11. Influence of La-Mn substitutions on magnetic properties of M-type strontium hexaferrites

    Science.gov (United States)

    Zi, Z. F.; Ma, X. H.; Wei, Y. Y.; Liu, Q. C.; Zhang, M.; Zhu, X. B.; Sun, Y. P.

    2018-05-01

    M-type strontium hexaferrites of Sr1-xLaxFe12-xMnxO19 (0.0≤x≤0.4) were synthesized by the chemical coprecipitation method. X-ray diffraction (XRD) studies indicate that the samples are single-phase with the space group of P63/mmc. The results of field-emission scanning electronic microscopy (FE-SEM) show that the grains are regular hexagonal platelets with sizes from 0.7 to 1.4 μm. It is observed that the value of Hc increases at low substitution (x ≤ 0.1), reaches a maximum at x = 0.1 and then decreases at x ≥ 0.1, while the value of Ms decreases monotonously with increasing x. The variations of magnetic properties can be tentatively attributed to the effects of La-Mn substitutions. The results above indicate that our samples might be promising candidates for permanent magnets in the future.

  12. Electrical conductivity of cobalt–titanium substituted SrCaM hexaferrites

    International Nuclear Information System (INIS)

    Eraky, M.R.

    2012-01-01

    A series of polycrystalline M-type hexagonal ferrites with the composition Sr 0.5 Ca 0.5 Co x Ti x Fe 12−2x O 19 (where x=0.0–0.8) were prepared by the conventional ceramic technique. The electrical conductivity has been measured from 300 to 590 K. The dc conductivity, σ dc , exhibited a semiconductor behavior. The negative sign of thermoelectric power coefficient S reveals that all samples are n-type semiconductors. Both σ dc and mobility, μ d , increases with the substitution of Co 2+ and Ti 4+ ions, reach maximum at x=0.4 and start decreasing at x>0.4. Many conduction mechanisms were discussed to explain the electric conduction in the system. It was found that the hopping conduction is the predominant conduction mechanism. For samples with compositional parameter x=0.0 and 0.8, the band conduction mechanism shares in electric conduction beside the hopping process. - Highlights: ► SrCaCoTiM hexaferrites have been prepared by conventional ceramic technique. ► The electrical conductivity exhibited a semiconductor behavior. There is an increase in conductivity up to x=0.4 for Co and Ti substitution. ► The hopping conduction is the predominant conduction mechanism.

  13. Growth, structural and magnetic characterization of Al-substituted barium hexaferrite single crystals

    International Nuclear Information System (INIS)

    Vinnik, D.A.; Zherebtsov, D.A.; Mashkovtseva, L.S.; Nemrava, S.; Bischoff, M.; Perov, N.S.; Semisalova, A.S.; Krivtsov, I.V.; Isaenko, L.I.; Mikhailov, G.G.; Niewa, R.

    2014-01-01

    Highlights: • Growth of large Al-substituted crystals BaFe 12−x Al x O 19. • Al-content controllable by flux composition. • Crystallographic site preference of Al unraveled. • Magnetic characterization depending on Al-content. - Abstract: Large single crystals of aluminum-substituted M-type barium hexaferrite BaFe 12−x Al x O 19 were obtained from carbonate flux. The Al content in the crystals can be controlled via the Al content of the flux up to x = 1.1 according to single crystal X-ray structure refinements. Al shows a distinct preference to substitute Fe on crystallographic sites with high coordination numbers by oxygen atoms, whereas no significant amounts of Al can be found on a tetrahedrally coordinated site. An increasing amount of the aluminum dopant results in a monotonous reduction of the Curie temperature from 440 to 415 °C and the saturation magnetization at room temperature from 68 to 57 emu/g for single crystal and from 61 to 53 emu/g for powder samples

  14. Structural and magnetic Properties of TbZn-substituted calcium barium M-type nano-structured hexa-ferrites

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Hasan M. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Department of Electronics, University of York, York YO10 5DD (United Kingdom); Islam, M.U., E-mail: dr.misbahulislam@bzu.edu.pk [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Xu, Yongbing [Department of Electronics, University of York, York YO10 5DD (United Kingdom); Nanjing–York International Centre of Spintronics and Nano-Engineering, Nanjing University, Nanjing 210093 (China); Asif Iqbal, M. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); National University of Science and Technology, College of E and ME, Islamabad (Pakistan); Ali, Irshad [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan)

    2014-03-15

    Highlights: • Tb–Zn substituted Ca{sub 0.5}Ba{sub 0.5}Fe{sub 12}O{sub 19} samples exhibit single magnetoplumbite phase. • Lattice parameters a and c have increasing values. • Coercivity can be tuned at lower substitution level • Crystallites size was found in the range 18–25 nm by TEM and by Scherrer formula. • These hexa-ferrites are suitable for microwave devices and magnetic recording media. -- Abstract: Effect of TbZn substitution on the structural and magnetic properties of Ca{sub 0.5}Ba{sub 0.5−x}Tb{sub x}Zn{sub y}Fe{sub 12−y}O{sub 19}, (x = 0.00–0.10; y = 0.00–1.00) ferrites prepared by sol–gel auto combustion is reported. The synthesized samples were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Vibrating Sample magnetometery. The X-ray diffraction analysis confirmed single phase M-type hexa-ferrite structure. The lattice parameters were found to increase as TbZn contents increases, which is attributed to the ionic sizes of the implicated cations. The TbZn seems to be completely soluble in the lattice. The results of scanning electron microscopy and transmission electron microscopy shows that the grain size decreases with increase of TbZn substitution. The coercivity values (1277–2025 Oe) of all samples lies in the range of M-type hexa-ferrite and indicate that an increase of anisotropy was achieved by substitution of TbZn, while the size of nanoparticles was drastically reduced between 18 and 25 nm. The increased anisotropy and fine particle size are useful for many applications, such as improving signal noise ratio of recording devices.

  15. Polyacrylamide Ferrogels with Magnetite or Strontium Hexaferrite: Next Step in the Development of Soft Biomimetic Matter for Biosensor Applications

    Directory of Open Access Journals (Sweden)

    Alexander P. Safronov

    2018-01-01

    Full Text Available Magnetic biosensors are an important part of biomedical applications of magnetic materials. As the living tissue is basically a “soft matter.” this study addresses the development of ferrogels (FG with micron sized magnetic particles of magnetite and strontium hexaferrite mimicking the living tissue. The basic composition of the FG comprised the polymeric network of polyacrylamide, synthesized by free radical polymerization of monomeric acrylamide (AAm in water solution at three levels of concentration (1.1 M, 0.85 M and 0.58 M to provide the FG with varying elasticity. To improve FG biocompatibility and to prevent the precipitation of the particles, polysaccharide thickeners—guar gum or xanthan gum were used. The content of magnetic particles in FG varied up to 5.2 wt % depending on the FG composition. The mechanical properties of FG and their deformation in a uniform magnetic field were comparatively analyzed. FG filled with strontium hexaferrite particles have larger Young’s modulus value than FG filled with magnetite particles, most likely due to the specific features of the adhesion of the network’s polymeric subchains on the surface of the particles. FG networks with xanthan are stronger and have higher modulus than the FG with guar. FG based on magnetite, contract in a magnetic field 0.42 T, whereas some FG based on strontium hexaferrite swell. Weak FG with the lowest concentration of AAm shows a much stronger response to a field, as the concentration of AAm governs the Young’s modulus of ferrogel. A small magnetic field magnetoimpedance sensor prototype with Co68.6Fe3.9Mo3.0Si12.0B12.5 rapidly quenched amorphous ribbon based element was designed aiming to develop a sensor working with a disposable stripe sensitive element. The proposed protocol allowed measurements of the concentration dependence of magnetic particles in gels using magnetoimpedance responses in the presence of magnetite and strontium hexaferrite ferrogels

  16. Magnetic Properties and Structural Characteristics of BaFe12O19 Hexaferrites Synthesized by the Zol-Gel Combustion

    Science.gov (United States)

    Zhuravlev, V. A.; Itin, V. I.; Minin, R. V.; Lopushnyak, Yu. M.; Velikanov, D. A.

    2018-03-01

    The phase structure, structural parameters, and basic magnetic characteristics of BaFe12O19 hexaferrites prepared by the zol-gel combustion method with subsequent annealing at a temperature of 850°C for 6 h are investigated. The influence of the organic fuel type on the properties of synthesized materials is analyzed. Values of the saturation magnetization and the anisotropy field are determined. It is established that they depend on the organic fuel type. It is shown that powders synthesized with citric acid used as a fuel have the largest particle sizes and the highest saturation magnetization.

  17. Microwave absorption and {sup 57}Fe Mössbauer properties of Ni-Ti doped barium hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Harker, S. J., E-mail: stephen.harker@defence.gov.au [Russell Offices, Program Office, Defence Science and Technology Organisation (Australia); Stewart, G. A.; Hutchison, W. D. [UNSW Canberra at the Australian Defence Force Academy, School of Physical, Environmental and Mathematical Sciences (Australia); Amiet, A. [Defence Science and Technology Organisation, Maritime Division (Australia); Tucker, D. [UNSW Canberra at the Australian Defence Force Academy, School of Physical, Environmental and Mathematical Sciences (Australia)

    2015-04-15

    The impact of doping the Fe component of barium hexaferrite with Ni{sub 0.5}Ti{sub 0.5} is investigated using x-ray powder diffraction, {sup 57}Fe Mössbauer spectroscopy and microwave network analysis. The dopant ions exhibit a preference for the 2b, 4f{sub 2} and 12k-sites and the unit cell volume is observed to decrease. The ferromagnetic resonance frequency is reduced by about 11.5 GHz for each additional dopant ion per formula unit.

  18. Magneto-optical effects of reflection on monocrystals of ferrite garnets, orthoferrites hexaferrites and hematite. [Yttrium oxides iron oxides; europium oxides; bismuth oxides

    Energy Technology Data Exchange (ETDEWEB)

    Krinchik, G S; Krylova, V A; Khrebtov, A P; Chepurova, E E

    1975-01-01

    The results of experimental studies of the equatorial Kerr effect in visible and ultraviolet ranges of the spectrum are given for ferromagnetic dielectrics of different classes: ferrimagnetic ferrite garnets and hexaferrites, as well as weakly ferromagnetic orthoferrites and hematite. A method for the nondestructive magneto-optical data readout using reflected light is proposed and described.

  19. The mechanically induced structural disorder in barium hexaferrite, BaFe12O19, and its impact on magnetism

    CERN Document Server

    Šepelák, V; Witte, R; Röder, J; Menzel, D; Schuster, R H; Hahn, H; Heitjans, P; Becker, K-D

    2014-01-01

    The response of the structure of the M-type barium hexaferrite (BaFe12O19) to mechanical action through high-energy milling and its impact on the magnetic behaviour of the ferrite are investigated. Due to the ability of the Fe-57 Mossbauer spectroscopic technique to probe the environment of the Fe nuclei, a valuable insight on a local atomic scale into the mechanically induced changes in the hexagonal structure of the material is obtained. It is revealed that the milling of BaFe12O19 results in the deformation of its constituent polyhedra (FeO6 octahedra, FeO4 tetrahedra and FeO5 triangular bi-pyramids) as well as in the mechanically triggered transition of the Fe3+ cations from the regular 12k octahedral sites into the interstitial positions provided by the magnetoplumbite structure. The response of the hexaferrite to the mechanical treatment is found to be accompanied by the formation of a non-uniform nanostructure consisting of an ordered crystallite surrounded/separated by a structurally disordered surfac...

  20. Role of grain boundaries in the conduction of Eu–Ni substituted Y-type hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Irshad, E-mail: irshadalibzu@gmail.com [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Islam, M.U. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Naeem Ashiq, Muhammad, E-mail: naeemashiqqau@yahoo.com [Institute of Chemical Sciences, Bahauddin Zakariya University, Multan 60800 (Pakistan); Asif Iqbal, M. [National University of Sciences and Technology, EME College, Islamabad (Pakistan); Khan, Hasan M. [Department of Physics, Bahauddin Zakariya University, Multan 60800 (Pakistan); Murtaza, G. [Centre for Advanced Studies in Physics, Government College University, Lahore 54000 (Pakistan)

    2014-08-01

    Single phase nanostructured (Eu–Ni) substituted Y-type hexaferrites with nominal composition of Sr{sub 2}Co{sub 2−x}Ni{sub x}Eu{sub y}Fe{sub 12−y}O{sub 22} (x=0.0–1, y=0.0–0.1) were synthesized by the microemulsion method. Temperature dependent DC electrical conductivity and drift mobility were found in good agreement with each other, reflecting semiconducting behavior. The presence of Debye peaks in imaginary electric modulus curves confirmed the existence of relaxation phenomena in given frequency range. The AC conductivity follows power law, with exponent (n) value, ranges from 0.81–0.97, indicating that the mechanism is due to polaron hopping. In the present ferrite system, Cole–Cole plots were used to separate the grain and grain boundary effects. Eu–Ni substitution leads to a remarkable rise of grain boundary resistance as compared to the grain resistance. As both AC conductivity and Cole–Cole plots are the functions of concentration, they reveal the dominant contribution of grain boundaries in the conduction mechanism. It was also observed that the AC activation energy is lower than the DC activation energy. Appreciable improved values of quality factor suggested the possible use of these synthesized materials for power applications and high frequency multilayer chip inductors. - Highlights: • Single phase nanostructures were synthesized by the micro-emulsion method. • Substitution leads to a remarkable rise of grain boundary resistance. • The AC activation energy is lower than the DC activation energy. • Improved values of quality factor make these materials useful for high frequency multilayer chip inductors.

  1. Structural and magnetic properties of conventional and microwave treated Ni-Zr doped barium strontium hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Kanagesan, S., E-mail: kanagu1980@gmail.com [Center for Materials Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603203, Tamil Nadu (India); Jesurani, S. [Center for Materials Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603203, Tamil Nadu (India); Department of Physics, Jeyaraj Annapackium College for Women, Periyakulam 625601, Tamil Nadu (India); Velmurugan, R. [Center for Materials Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603203, Tamil Nadu (India); Prabu, S. [Department of Chemistry, S.K.P. Engineering College, Anna University of Technology Chennai, Thiruvannamalai 606 611, Tamil Nadu (India); Kalaivani, T. [Center for Materials Science and Nano Devices, Department of Physics, SRM University, Kattankulathur 603203, Tamil Nadu (India)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Saturation magnetization increases whereas the coercivity decreases. Black-Right-Pointing-Pointer The transition from hard phase to soft phase. Black-Right-Pointing-Pointer Therefore, it is used for high-density magnetic recording applications. -- Abstract: M-type hexaferrites of component B{sub 0.5}Sr{sub 0.5}Fe{sub 12-2x}Ni{sub x}Zr{sub x}O{sub 19} were investigated. The XRD patterns show single phase of the magnetoplumbite barium strontium ferrite and no other phases were present. Significant increase in line broadening of the XRD patterns was observed indicating a decrease of grain size. The samples exhibit well defined crystallization; all of them are hexagonal platelet grains. As the substitution level increased x = 0.2-0.8 mol%, the grains are agglomerated and the average diameter increased. The H{sub c} decreases remarkably with increasing Ni and Zr ions content. It was found that the particle size could be effectively decreased and coercivity H{sub c} could easily be controlled by varying the concentration (x) without significantly decreasing saturation magnetization. In particular, Ba{sub 0.5}Sr{sub 0.5}Fe{sub 12-2x}Ni{sub x}Zr{sub x}O{sub 19} with x = 0.2, 0.4, 0.6, 0.8 mol% has suitable magnetic characteristics with particle size small enough for high-density magnetic recording applications.

  2. Tailoring structure and magnetic characteristics of strontium hexaferrite via Al doping engineering

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.Z.; Hai, Y.N. [State Key Lab of High Power Semiconductor Laser of Changchun University Science and Technology, Changchun University Science and Technology, Changchun 130022 (China); Yao, B., E-mail: binyao@jlu.edu.cn [State Key Lab of Superhard Materials and Department of Physics, Jilin University, Changchun 130023 (China); Xu, Y. [School of Physics, Northeast Normal University, Changchun 130024 (China); Shan, L. [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry and Department of Chemistry, Jilin University, Changchun 130012 (China); Xu, L.; Tang, J.L.; Wang, Q.H. [State Key Lab of High Power Semiconductor Laser of Changchun University Science and Technology, Changchun University Science and Technology, Changchun 130022 (China)

    2017-01-15

    Emerging structure and magnetic properties of Al{sup 3+}-modified SrFe{sub 12}O{sub 19} M-type hexaferrite system (SrAl{sub x}Fe{sub 12−x}O{sub 19}) had been studied in detail via doping engineering. With Al{sup 3+} ion nominal content ranging from 0 to 4 (0≤x≤4), the lattice parameters decrease due to the substitution of Fe{sup 3+} ions by smaller Al{sup 3+} ions, and the magnetization shows a continuous reduction with the increasing of Al content. For the coercivity, its value initially increases, reaching a maximum value of 16,876.9 Oe at x=3, and then reduces with the Al content further increase. When all the Fe{sup 3+} ions (x=4) are replaced by Al{sup 3+} ions, the net magnetic moment will be closed to zero, that will weaken the exchange interaction between Fe{sup 3+} ions, resulting in decrease of coercivity sharply and transformation ferrimagnetism into antiferromagnetism. The mechanism of the improvement of the magnetic properties induced by Al doping is discussed in the present work. - Highlights: • The coercivity reach a maximum value at x=3 in the SrAl{sub x}Fe{sub 12−x}O{sub 19}. • The coercivity of SrFe{sub 12}O{sub 19} increases due to nonmagnetic Al doping. • The saturation magnetization of SrFe{sub 12}O{sub 19} decreases due to nonmagnetic Al doping. • The transformation ferrimagnetism into antiferromagnetism by nonmagnetic Al doping.

  3. Ultrahard carbon nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Siegal, M. P. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Tallant, D. R. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Provencio, P. N. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Overmyer, D. L. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Simpson, R. L. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States); Martinez-Miranda, L. J. [Department of Materials and Nuclear Engineering, University of Maryland, College Park, Maryland 20742 (United States)

    2000-05-22

    Modest thermal annealing to 600 degree sign C of diamondlike amorphous-carbon (a-C) films grown at room temperature results in the formation of carbon nanocomposites with hardness similar to diamond. These nanocomposite films consist of nanometer-sized regions of high density a-C embedded in an a-C matrix with a reduced density of 5%-10%. We report on the evolution of density and bonding topologies as a function of annealing temperature. Despite a decrease in density, film hardness actually increases {approx}15% due to the development of the nanocomposite structure. (c) 2000 American Institute of Physics.

  4. Ultrahard carbon nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    SIEGAL,MICHAEL P.; TALLANT,DAVID R.; PROVENCIO,PAULA P.; OVERMYER,DONALD L.; SIMPSON,REGINA L.; MARTINEZ-MIRANDA,L.J.

    2000-01-27

    Modest thermal annealing to 600 C of diamondlike amorphous-carbon (a-C) films grown at room temperature results in the formation of carbon nanocomposites with hardness similar to diamond. These nanocomposite films consist of nanometer-sized regions of high density a-C embedded in an a-C matrix with a reduced density of 5--10%. The authors report on the evolution of density and bonding topologies as a function of annealing temperature. Despite a decrease in density, film hardness actually increases {approximately} 15% due to the development of the nanocomposite structure.

  5. Tribology of Nanocomposites

    CERN Document Server

    2013-01-01

    This book provides recent information on nanocomposites tribology. Chapter 1 provides information on tribology of bulk polymer nanocomposites and nanocomposite coatings. Chapter 2 is dedicated to nano and micro PTFE for surface lubrication of carbon fabric reinforced polyethersulphone composites. Chapter 3 describes Tribology of MoS2 -based nanocomposites. Chapter 4 contains information on friction and wear of Al2O2 -based composites with dispersed and agglomerated nanoparticles. Finally, chapter 5 is dedicated to wear of multi-scale phase reinforced composites. It is a useful reference for academics, materials and physics researchers, materials, mechanical and manufacturing engineers, both as final undergraduate and postgraduate levels. It is a useful reference for academics, materials and physics researchers, materials, mechanical and manufacturing engineers, both as final undergraduate and postgraduate levels.

  6. Magnetic nanocomposite sensor

    KAUST Repository

    Alfadhel, Ahmed; Li, Bodong; Kosel, Jü rgen

    2016-01-01

    A magnetic nanocomposite device is described herein for a wide range of sensing applications. The device utilizes the permanent magnetic behavior of the nanowires to allow operation without the application of an additional magnetic field

  7. Nano-composite materials

    Science.gov (United States)

    Lee, Se-Hee; Tracy, C. Edwin; Pitts, J. Roland

    2010-05-25

    Nano-composite materials are disclosed. An exemplary method of producing a nano-composite material may comprise co-sputtering a transition metal and a refractory metal in a reactive atmosphere. The method may also comprise co-depositing a transition metal and a refractory metal composite structure on a substrate. The method may further comprise thermally annealing the deposited transition metal and refractory metal composite structure in a reactive atmosphere.

  8. Growing barium hexaferrite (BaFe{sub 12}O{sub 19}) thin films using chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Budiawanti, Sri, E-mail: awanty77@yahoo.com [Graduate Program of Materials Science, Department of Physics, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia); Faculty of Teacher Training and Education, Sebelas Maret University (Indonesia); Soegijono, Bambang [Multiferroic Laboratory, Department of Physics, FMIPA, Universitas Indonesia, Kampus UI Depok (Indonesia)

    2016-04-19

    Barium hexaferrite (BaFe{sub 12}O{sub 19}, or simply known as BaM) thin films has been recognized as a potential candidate for microwave-based devices, magnetic recording media and data storage. To grow BaM thin films, chemical solution deposition is conducted using the aqueous solution of metal nitrates, which involves spin coatings on Si substrates. Furthermore, Thermal Gravimeter Analysis (TGA), X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM) are applied to evaluate the decomposition behavior, structure, morphology, and magnetic properties of BaM thin films. Additionally, the effects of number of layers variation are also investigated. Finally, magnetic properties analysis indicates the isotropic nature of the films.

  9. Growing barium hexaferrite (BaFe_1_2O_1_9) thin films using chemical solution deposition

    International Nuclear Information System (INIS)

    Budiawanti, Sri; Soegijono, Bambang

    2016-01-01

    Barium hexaferrite (BaFe_1_2O_1_9, or simply known as BaM) thin films has been recognized as a potential candidate for microwave-based devices, magnetic recording media and data storage. To grow BaM thin films, chemical solution deposition is conducted using the aqueous solution of metal nitrates, which involves spin coatings on Si substrates. Furthermore, Thermal Gravimeter Analysis (TGA), X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and Vibrating Sample Magnetometer (VSM) are applied to evaluate the decomposition behavior, structure, morphology, and magnetic properties of BaM thin films. Additionally, the effects of number of layers variation are also investigated. Finally, magnetic properties analysis indicates the isotropic nature of the films.

  10. Gigantic terahertz magnetochromism via electromagnons in the hexaferrite magnet Ba2Mg2Fe12O22

    Science.gov (United States)

    Kida, N.; Kumakura, S.; Ishiwata, S.; Taguchi, Y.; Tokura, Y.

    2011-02-01

    Effects of temperature (6-225 K) and magnetic field (0-7 T) on the low-energy (1.2-5 meV) electrodynamics of the electromagnon, the magnetic resonance driven by the light electric field, have been investigated for a hexaferrite magnet Ba2Mg2Fe12O22 by using terahertz time-domain spectroscopy. We find the gigantic terahertz magnetochromism via electromagnons; the magnetochromic change, as defined by the difference of the absorption intensity with and without magnetic field, exceeds 500% even at 0.6 T. The results arise from the fact that the spectral intensity of the electromagnon critically depends on the magnetic structure. With changing the conical spin structures in terms of the conical angle θ from the proper screw (θ=0°) to the ferrimagnetic (θ=90°) through the conical spin-ordered phases (0°origin of this electromagnon is argued in terms of the exchange-striction mechanism.

  11. Nanofiber production of poly (vinylidene fluoride) / hexaferrite, obtained by Blow Spinning Technique; Producao de nanofibras de poli (fluoreto de vinilideno)/hexaferrita, obtidos pela tecnica Blow Spinning

    Energy Technology Data Exchange (ETDEWEB)

    Dias, G.C.; Zadorosny, L.; Malmonge, J.A.; Malmonge, L.F., E-mail: gabriel.fct@gmail.com [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira, SP (Brazil)

    2014-07-01

    In this study, fibrous films of poly (vinylidene fluoride) - PVDF with barium hexaferrite particles were obtained by Solution Blow Spinning technique. In such technique, the polymer solution is injected through an inner nozzle which experiences the action of an accelerated flux of gas that drags and stretches the jet solution forming the nanofibers. The films were obtained from solutions of PVDF/DMF (30% w/v), which was incorporated into barium hexaferrite particles in proportions of 1, 3 and 5% (w / w). The results of the micrographs revealed the formation of a fibrous film with good dispersion of the particles. Xray analyzes showed the predominance of the β crystalline phase of PVDF. The increase of the amount of particles induces the appearance of a characteristic peak of PVDF. EDX measurements confirmed the presence of particles in the films. (author)

  12. Thermal Degradation of Nanocomposited PMMA/TiO2 Nanocomposites

    International Nuclear Information System (INIS)

    Hafizah, Nik Noor; Mamat, Mohamad Hafiz; Rusop, Mohamad; Said, Che Mohamad Som; Abidin, Mohd Hanafiah

    2013-01-01

    The polymer nanocomposite is a new choice to conventionally filled polymers. The lack of proper binding between the filler and the polymer can lead the decrease of the thermal and other properties of the nanocomposites. In this study, the nanocomposited PMMA/TiO 2 nanocomposites were prepared using sonication and solution casting method at different weight percent TiO 2 . The aims of adding TiO 2 in the PMMA is to study the effects of TiO 2 nanofiller on the thermal properties nanocomposites. FESEM results show the higher amounts of TiO 2 in PMMA increase the rough surface morphology of the samples. Further, the Raman results reveal that the TiO 2 nanofiller were successfully intercalated into the PMMA matrix. In addition, the thermal properties of nanocomposited PMMA/TiO 2 nanocomposites were increased with the addition of TiO 2 in the PMMA.

  13. Impacts of MnZn doping on the structural and magnetic properties of M-type SrCaLa hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yujie; Shao, Juxiang; Wang, Fanhou; Huang, Duohui [Yibin University, Computational Physics Key Laboratory of Sichuan Province, School of Physics and Electronic Engineering, Yibin (China); Liu, Xiansong [Anhui University, Engineering Technology Research Center of Magnetic Materials, Anhui Province, School of Physics and Materials Science, Hefei (China)

    2017-05-15

    M-type hexaferrites with chemical compositions of Sr{sub 0.5}Ca{sub 0.2}La{sub 0.3}Fe{sub 12.0-2x} (MnZn){sub x} O{sub 19} (0.0 ≤ x ≤ 0.5) were synthesized by the traditional ceramic method. The crystal structure of M-type hexaferrite samples was examined by X-ray diffraction. The structural analyses reveal that all samples are in single M-type hexagonal phase and no secondary phase is present. A physical property measurement system-vibrating sample magnetometer was used to measure the magnetic properties of M-type hexaferrite samples. The saturation magnetization (M{sub s}), remanent magnetization (M{sub r}) and coercivity (H{sub c}) were calculated from magnetic hysteresis loops. M{sub s} first increases with MnZn content (x) from 0.0 to 0.1, and then decreases with MnZn content (x) from 0.1 to 0.5. While, M{sub r} decreases with MnZn content (x) from 0.0 to 0.2, and then increases with MnZn content (x) from 0.2 to 0.5. H{sub c} first decreases with MnZn content (x) from 0.0 to 0.2, and then increase with MnZn content (x) from 0.2 to 0.5. (orig.)

  14. Conducting polyamine nanocomposites development

    International Nuclear Information System (INIS)

    Nascimento, R.C.; Maciel, T.C.G.L.; Guimaraes, M.J.O.C.; Garcia, M.E.F.

    2010-01-01

    Polymeric nanocomposites are hybrid materials formed by the combination of inorganic nanoparticles dispersed in a polymeric matrix with, at least, one dimension in the nanometer range. It was used as nanoparticles layered and tubular clay minerals, and its insertion and dispersion were conducted through the in situ polymerization technique. As the polymer matrix, it was utilized a polyamine, which, later, will be inserted in a polyacrylamide gel for the development of a compound that aggregates both main characteristics. The nanocomposites were prepared in different polymerization conditions (temperature, concentration and nanoparticle type) and characterized by XRD and FTIR. It was observed that regarding the polymerization conditions, the temperature had influence on the kind of material obtained and on the reaction speed; the type of nanoparticle affected its interaction with the polymer matrix, predominantly providing the formation of nanocomposites by the intercalation mechanism in the layered clay. (author)

  15. Nanocomposites for Machining Tools

    Directory of Open Access Journals (Sweden)

    Daria Sidorenko

    2017-10-01

    Full Text Available Machining tools are used in many areas of production. To a considerable extent, the performance characteristics of the tools determine the quality and cost of obtained products. The main materials used for producing machining tools are steel, cemented carbides, ceramics and superhard materials. A promising way to improve the performance characteristics of these materials is to design new nanocomposites based on them. The application of micromechanical modeling during the elaboration of composite materials for machining tools can reduce the financial and time costs for development of new tools, with enhanced performance. This article reviews the main groups of nanocomposites for machining tools and their performance.

  16. Chitosan-based nanocomposites

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2012-08-01

    Full Text Available , and hygiene devices. They thus represent a strong and emerging answer for improved and eco-friendly materials. This chapter reviews the recent developments in the area of chitosan-based nanocomposites, with a special emphasis on clay-containing nanocomposites...-sized mineral fillers like silica, talc, and clay are added to reduce the cost and improve chitosan’s performance in some way. However, the mechanical properties such as elongation at break and tensile strength of these composites decrease with the incorporation...

  17. Microwave absorption properties of reduced graphene oxide strontium hexaferrite/poly(methyl methacrylate) composites

    Science.gov (United States)

    Acharya, Sanghamitra; Ray, J.; Patro, T. U.; Alegaonkar, Prashant; Datar, Suwarna

    2018-03-01

    The key factors to consider when designing microwave absorber materials for eradication of electromagnetic (EM) pollution are absorption of incident EM waves and good impedance matching. By keeping these things in mind, flexible microwave absorber composite films can be fabricated by simple gel casting techniques using reduced graphene oxide (RGO) and strontium ferrite (SF) in a poly(methyl methacrylate) (PMMA) matrix. SF nanoparticles are synthesized by the well known sol-gel method. Subsequently, reduced graphene oxide (RGO) and SF nanocomposite (RGOSF) are prepared through a chemical reduction method using hydrazine. The structure, morphology, chemical composition, thermal stability and magnetic properties of the nanocomposite are characterized in detail by various techniques. The SF particles are found to be nearly 500 nm and decorated on RGO sheets as revealed by field emission scanning electron microscopy and transmission electron microscopy analysis. Fourier transform infrared and and Raman spectroscopy clearly show the presence of SF in the graphene sheet by the lower peak positions. Finally, ternary polymer composites of RGO/SF/PMMA are prepared by an in situ polymerization method. Magnetic and dielectric studies of the composite reveal that the presence of RGO/SF/PMMA lead to polarization effects contributing to dielectric loss. Also, RGO surrounding SF provides a conductive network in the polymer matrix which is in turn responsible for the magnetic loss in the composite. Thus, the permittivity as well as the permeability of the composite can be controlled by an appropriate combination of RGO and SF in PMMA. More than 99% absorption efficiency is achieved by a suitable combination of magneto-dielectric coupling in the X-band frequency range by incorporating 9 wt% of RGO and 1 wt% of SF in the polymer matrix.

  18. LIGNOCELLULOSE NANOCOMPOSITE CONTAINING COPPER SULFIDE

    OpenAIRE

    Sanchi Nenkova; Peter Velev; Mirela Dragnevska; Diyana Nikolova; Kiril Dimitrov

    2011-01-01

    Copper sulfide-containing lignocellulose nanocomposites with improved electroconductivity were obtained. Two methods for preparing the copper sulfide lignocellulose nanocomposites were developed. An optimization of the parameters for obtaining of the nanocomposites with respect to obtaining improved electroconductivity, economy, and lower quantities and concentration of copper and sulfur ions in waste waters was conducted. The mechanisms and schemes of delaying and subsequent connection of co...

  19. Polyolefin nanocomposites in situ polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Galland, Griselda Barrera; Fim, Fabiana de C.; Milani, Marceo A.; Silva, Silene P. da; Forest, Tadeu; Radaelli, Gislaine, E-mail: griselda.barrera@ufrgs.br [Universidade Federal do Rio Grande de Sul - UFRGS, Porto Alegre, RS (Brazil); Basso, Nara R.S. [Pontificia Universidade Catolica do Rio Grande do Sul, Porto Alegre, RS (Brazil); Quijada, Raul [Universidad de Chile, Santiago (Chile)

    2011-07-01

    Polyethylene and polypropylene nanocomposites using grapheme nanosheets and treated chrysotile have been synthesized by in situ polymerization using metallocene catalysts. The fillers have been submitted to acid, thermal and/ou ultrasound treatments before to introduce them into the polymerization reactor. A complete characterization of the fillers has been done. The nanocomposites have been characterized by SEM, TEM, DRX and AFM. The thermal, mechanic -dynamic, mechanical and electrical properties of the nanocomposites are discussed. (author)

  20. Polyolefin nanocomposites in situ polymerization

    International Nuclear Information System (INIS)

    Galland, Griselda Barrera; Fim, Fabiana de C.; Milani, Marceo A.; Silva, Silene P. da; Forest, Tadeu; Radaelli, Gislaine; Basso, Nara R.S.; Quijada, Raul

    2011-01-01

    Polyethylene and polypropylene nanocomposites using grapheme nanosheets and treated chrysotile have been synthesized by in situ polymerization using metallocene catalysts. The fillers have been submitted to acid, thermal and/ou ultrasound treatments before to introduce them into the polymerization reactor. A complete characterization of the fillers has been done. The nanocomposites have been characterized by SEM, TEM, DRX and AFM. The thermal, mechanic -dynamic, mechanical and electrical properties of the nanocomposites are discussed. (author)

  1. Enhancement of soft magnetic properties of La–Zn co-doped nanocrystalline Ni{sub 2}Y hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Hosseinkhan Nejad, Ehsan, E-mail: ehsanhkhani66@gmail.com [Department of Material Science and Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Farzin, Yousef Alizad [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 14395-553, Tehran (Iran, Islamic Republic of); Heydari, Mohammad Ali [Department of Material Science and Engineering, Azad University of Saveh, Saveh (Iran, Islamic Republic of)

    2017-02-01

    The La-Zn substituted nanocrystalline Sr{sub 2−x}La{sub x}Ni{sub 2}Fe{sub 12−x}Zn{sub x}O{sub 22} (with x=0.0, 0.4, 0.5, 0.6, 0.7, 0.8 and 0.9) hexaferrites were prepared using sol-gel auto-combustion method to investigate the microstructure and magnetic properties. Fourier transform infrared spectroscopy (FT-IR) spectra showed two main absorption bands at 429 and 594 cm{sup −1} corresponding to the stretching and vibration of tetrahedral and octahedral groups in S blocks. The X-ray diffraction pattern confirmed the phase formation of Y-type hexaferrite with R-3 m space group which also provided the lattice constants and crystallite sizes of each product. Furthermore, the crystallite size (D) was found to be in the range of 31.4–43.1 nm. Field emission electron microscopy (FESEM) images confirmed that the grain size was reduced from 600 to 150 nm due to the increase of dopant cations and, subsequently, caused soft magnetic properties to improve. By performing a thorough investigation on the M–H hysteresis loops, it was found that the magnetization first increased up to x=0.7 and then decreased, while coercivity monotonously decreased from 1313 to 569 Oe. This behavior can be attributed to the migration of Fe3+ ions from spin-down to spin-up, local strains, deviation of spin arrangement and strength of superexchange interactions. - Highlights: • A systematic study was done on the effect of La–Zn substitution of Ni{sub 2}Y. • The crystallite size of this ferrites is in the range of 31.4–41.3 nm. • Coercivity of synthesis samples monotonously decreased from 1313 to 569 Oe. • The magnetization and the coercivity strongly depend on La–Zn substitution. • The soft magnetic properties of ferrites improved by increasing of dopant cations.

  2. Smart Nacre-inspired Nanocomposites.

    Science.gov (United States)

    Peng, Jingsong; Cheng, Qunfeng

    2018-03-15

    Nacre-inspired nanocomposites with excellent mechanical properties have achieved remarkable attention in the past decades. The high performance of nacre-inspired nanocomposites is a good basis for the further application of smart devices. Recently, some smart nanocomposites inspired by nacre have demonstrated good mechanical properties as well as effective and stable stimuli-responsive functions. In this Concept, we summarize the recent development of smart nacre-inspired nanocomposites, including 1D fibers, 2D films and 3D bulk nanocomposites, in response to temperature, moisture, light, strain, and so on. We show that diverse smart nanocomposites could be designed by combining various conventional fabrication methods of nacre-inspired nanocomposites with responsive building blocks and interface interactions. The nacre-inspired strategy is versatile for different kinds of smart nanocomposites in extensive applications, such as strain sensors, displays, artificial muscles, robotics, and so on, and may act as an effective roadmap for designing smart nanocomposites in the future. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Fabrication and characterization of magnetically tunable metal-semiconductor schottky diode using barium hexaferrite thin film on gold

    Science.gov (United States)

    Kaur, Jotinder; Sharma, Vinay; Sharma, Vipul; Veerakumar, V.; Kuanr, Bijoy K.

    2016-05-01

    Barium Hexaferrite (BaM) is an extensively studied magnetic material due to its potential device application. In this paper, we study Schottky junction diodes fabricated using gold and BaM and demonstrate the function of a spintronic device. Gold (50 nm)/silicon substrate was used to grow the BaM thin films (100-150 nm) using pulsed laser deposition. I-V characteristics were measured on the Au/BaM structure sweeping the voltage from ±5 volts. The forward and reverse bias current-voltage curves show diode like rectifying characteristics. The threshold voltage decreases while the output current increases with increase in the applied external magnetic field showing that the I-V characteristics of the BaM based Schottky junction diodes can be tuned by external magnetic field. It is also demonstrated that, the fabricated Schottky diode can be used as a half-wave rectifier, which could operate at high frequencies in the range of 1 MHz compared to the regular p-n junction diodes, which rectify below 10 kHz. In addition, it is found that above 1 MHz, Au/BaM diode can work as a rectifier as well as a capacitor filter, making the average (dc) voltage much larger.

  4. Magnetic properties of in-plane oriented barium hexaferrite thin films prepared by direct current magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaozhi; Yue, Zhenxing, E-mail: yuezhx@mail.tsinghua.edu.cn; Meng, Siqin; Yuan, Lixin [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2014-12-28

    In-plane c-axis oriented Ba-hexaferrite (BaM) thin films were prepared on a-plane (112{sup ¯}0) sapphire (Al{sub 2}O{sub 3}) substrates by DC magnetron sputtering followed by ex-situ annealing. The DC magnetron sputtering was demonstrated to have obvious advantages over the traditionally used RF magnetron sputtering in sputtering rate and operation simplicity. The sputtering power had a remarkable influence on the Ba/Fe ratio, the hematite secondary phase, and the grain morphology of the as-prepared BaM films. Under 80 W of sputtering power, in-plane c-axis highly oriented BaM films were obtained. These films had strong magnetic anisotropy with high hysteresis loop squareness (M{sub r}/M{sub s} of 0.96) along the in-plane easy axis and low M{sub r}/M{sub s} of 0.03 along the in-plane hard axis. X-ray diffraction patterns and pole figures revealed that the oriented BaM films grew via an epitaxy-like growth process with the crystallographic relationship BaM (101{sup ¯}0)//α-Fe{sub 2}O{sub 3}(112{sup ¯}0)//Al{sub 2}O{sub 3}(112{sup ¯}0)

  5. High quality Y-type hexaferrite thick films for microwave applications by an economical and environmentally benign crystal growth technique

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Bolin; Chen, Yajie, E-mail: y.chen@neu.edu; Gillette, Scott; Su, Zhijuan; Harris, Vincent G. [Center for Microwave Magnetic Materials and Integrated Circuits and Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States); Wolf, Jason; McHenry, Michael E. [Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States)

    2014-02-17

    Thick barium hexaferrite Ba{sub 2}Zn{sub 2}Fe{sub 12}O{sub 22} (i.e., Zn{sub 2}Y) films having thicknesses of ∼100 μm were epitaxially grown on MgO (111) substrates using an environmentally benign ferrite-salt mixture by vaporizing the salt. X-ray diffraction pole figure analyses showed (00l) crystallographic alignment with little in plane dispersion confirming epitaxial growth. Saturation magnetization, 4πM{sub s}, was measured for as-grown films to be 2.51 ± 0.1 kG with an out of plane magnetic anisotropy field H{sub A} of 8.9 ± 0.1 kOe. Ferromagnetic resonance linewidth, as the peak-to-peak power absorption derivative at 9.6 GHz, was measured to be 62 Oe. These properties demonstrate a rapid, convenient, cost-effective, and nontoxic method of growing high quality thick crystalline ferrite films which could be used widely for microwave device applications.

  6. Synthesis and electrical behavior of Ni-Ti substituted Y-type hexaferrites for high frequency application

    Science.gov (United States)

    Ahmad, Bashir; Ashiq, Muhammad Naeem; Mumtaz, Saleem; Ali, Irshad; Najam-Ul-Haq, Muhmmad; Sadiq, Imran

    2018-04-01

    This article reports the fabrication of Ni-Ti doped derivatives of Sr2Co2Fe12-2xO22 by economical Sol-gel method. At room temperature X-ray diffraction (XRD) pattern of powder was obtained after sintering at 1050 °C. The XRD analysis revealed the formation of pure Sr-Y hexaferrite phase. It was found that the observed values of dielectric parameters decreased with increasing Ni-Ti substitution. The higher values of dielectric constants and dielectric loss factor at lower frequency were owing to surface charge polarization. In all the samples the resonance peaks were also observed. The observed room temperature DC electrical resistivity found to increase from 1.8x106 to 4.9x109 ohm cm. The observed activation energies values of the fabricated materials are found in 0.52-0.82 eV range. The decrease in dielectric parameters and increase in resistivity of the fabricated samples with substituents suggest these materials have worth application in micro-wave devices as such devices required highly resistive materials.

  7. Template synthesis and magnetic properties of highly aligned barium hexaferrite (BaFe12O19) nanofibers

    International Nuclear Information System (INIS)

    Huang, Boneng; Li, Congju; Wang, Jiaona

    2013-01-01

    Using electrospun poly(ethylene terephthalate)/citric acid (PET/CA) microfibers as the template, highly aligned barium hexaferrite (BaFe 12 O 19 ) nanofibers with diameters of ca. 800 nm and lengths up to 2 cm were synthesized by sol–gel precursor coating technique and subsequent high temperature calcination. Structural and morphological investigations revealed that individual BaFe 12 O 19 nanofibers were composed of numerous nanocrystallites stacking alternatively along the nanofiber axis, the average grain size was ca. 225 nm and the single crystallites on each BaFe 12 O 19 nanofibers were of random orientations. The formation mechanism of aligned BaFe 12 O 19 nanofibers was proposed based on experiment. The magnetic measurement revealed that the aligned BaFe 12 O 19 nanofibers exhibited orientation-dependent magnetic behavior with respect to the applied magnetic field. The magnetic anisotropy with the easy magnetizing axis along the length of the nanofibers was due to the shape anisotropy. Such aligned magnetic nanofibers can find relevance in application requiring an orientation-dependent physical response. - Highlights: ► A simple method was used to synthesize the aligned BaFe 12 O 19 nanofibers. ► The aligned BaFe 12 O 19 nanofibers display an obvious orientation-dependent magnetic behavior. ► The method can be readily applied to other aligned one-dimensional inorganic nanomaterials

  8. Effect of preparation conditions on fractal structure and phase transformations in the synthesis of nanoscale M-type barium hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Pashkova, E.V. [V.I. Vernadskii Institute of General and Inorganic Chemistry, 32/34 Prospect Palladina, Kyiv-142, 03680 (Ukraine); Solovyova, E.D., E-mail: solovyovak@mail.ru [V.I. Vernadskii Institute of General and Inorganic Chemistry, 32/34 Prospect Palladina, Kyiv-142, 03680 (Ukraine); Kotenko, I.E., E-mail: Hab2420@yahoo.com [National Technical University of Ukraine ' KPI' , Pr. Pobedy, 37, Kyiv-57 (Ukraine); Kolodiazhnyi, T.V., E-mail: kolodiazhnyi.taras@nims.go.jp [National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Belous, A.G., E-mail: belous@ionc.kar.net [V.I. Vernadskii Institute of General and Inorganic Chemistry, 32/34 Prospect Palladina, Kyiv-142, 03680 (Ukraine)

    2011-10-15

    The conditions of the synthesis of carbonate-hydroxide precursors (pH of FeOOH precipitation and heat treatment regimes) were studied in terms of their effect on the fractal structure and physical-chemical properties of precursors. Phase transformations which occur during the synthesis of nanosize M-type barium hexaferrite (BHF) were studied as well. The first structural level of precursors' aggregation for mass fractals, the correlation between fractal dimension and precursors' activity during the synthesis of BHF were determined. Synthesis parameters for the precursors with the optimal fractal structure were determined. These data permit an enhancement of the filtration coefficient of the precipitates by a factor of 4-5, obtaining substantial decrease in the temperature required for synthesis of a single-phase BHF, and monodispersed plate-like nanoparticles (60 nm diameter) with the shape anisotropy and good magnetic characteristics (saturation magnetization (M{sub s})=68,7 emu/g and coercitivity (H{sub c})=5440 Oe). - Highlights: > The nanosize M-type BHF obtained by precipitation of hydroxicarbonates technique. > Optimal fractal structure of a precursor for nanosize M-type BHF has been determined. > The precursor precipitated at pH 4.3 allows getting monodisperse particles of BHF.

  9. (BS-Mn) nanocomposite

    African Journals Online (AJOL)

    Bamboo supported manganese (BS-Mn) nanocomposite was prepared in a single pot system via bottom-up approach using a chemical reduction method. Langmuir surface area, BET surface area, and Single pore surface area were 349.70 m2/g, 218.90 m2/g, and 213.50 m2/g, respectively. The pore size (24.34 Ȧ); pore ...

  10. Multilayer graphene rubber nanocomposites

    Science.gov (United States)

    Schartel, Bernhard; Frasca, Daniele; Schulze, Dietmar; Wachtendorf, Volker; Krafft, Bernd; Morys, Michael; Böhning, Martin; Rybak, Thomas

    2016-05-01

    Multilayer Graphene (MLG), a nanoparticle with a specific surface of BET = 250 m2/g and thus made of only approximately 10 graphene sheets, is proposed as a nanofiller for rubbers. When homogenously dispersed, it works at low loadings enabling the replacement of carbon black (CB), increase in efficiency, or reduction in filler concentration. Actually the appropriate preparation yielded nanocomposites in which just 3 phr are sufficient to significantly improve the rheological, curing and mechanical properties of different rubbers, as shown for Chlorine-Isobutylene-Isoprene Rubber (CIIR), Nitrile-Butadiene Rubber (NBR), Natural Rubber (NR), and Styrene-Butadiene Rubber (SBR). A mere 3 phr of MLG tripled the Young's modulus of CIIR, an effect equivalent to 20 phr of carbon black. Similar equivalents are observed for MLG/CB mixtures. MLG reduces gas permeability, increases thermal and electrical conductivities, and retards fire behavior. The later shown by the reduction in heat release rate in the cone calorimeter. The higher the nanofiller concentration is (3 phr, 5 phr, and 10 phr was investigated), the greater the improvement in the properties of the nanocomposites. Moreover, the MLG nanocomposites improve stability of mechanical properties against weathering. An increase in UV-absorption as well as a pronounced radical scavenging are proposed and were proved experimentally. To sum up, MLG is interesting as a multifunctional nanofiller and seems to be quite ready for rubber development.

  11. Multifunctional Polymer Nanocomposites

    Science.gov (United States)

    Galaska, Alexandra Maria; Song, Haixiang; Guo, Zhanhu

    With more awareness of energy conversion/storage and saving, different strategies have been developed to utilize the sustainable and renewable energy. Introducing nanoscale fillers can make inert polymer matrix possess unique properties to satisfy certain functions. For example, alumina nanoparticles have strengthened the weak thermosetting polymers. A combined mixture of carbon nanofibers and magnetite nanoparticles have made the inert epoxy sensitive for magnetic field for sensing applications. Introducing silica nanoparticles into conductive polymers such as polyaniline has enhanced the giant magnetoresistance behaviors. The introduced nanoparticles have made the transparent polymer have the electromagnetic interference (EMI) shielding function while reduce the density significantly. With the desired miniaturization, the materials combining different functionalities have become importantly interesting. In this talk, methodologies to prepare nanocomposites and their effects on the produced nanocomposites will be discussed. A variety of advanced polymer nanocomposites will be introduced. Unique properties including mechanical, electrical, magnetoresistance etc. and the applications for environmental remediation, energy storage/saving, fire retardancy, electromagnetic interference shielding, and electronic devices will be presented.

  12. An introduction to polymer nanocomposites

    International Nuclear Information System (INIS)

    Armstrong, Gordon

    2015-01-01

    This review presents an overview of the formulation, characterization and range of applications for polymer nanocomposites. After explaining how material properties at the nanometre scale can vary compared to those observed at longer length scales, typical methods used to formulate and characterize nanocomposites at laboratory and industrial scale will be described. The range of mechanical, electrical and thermal properties obtainable from nanocomposite materials, with examples of current commercial applications, will be outlined. Formulation and characterization of nanoparticle, nanotube and graphene composites will be discussed by reference to nanoclay-based composites, as the latter are presently of most technological relevance. Three brief case studies are presented to demonstrate how structure/property relationships may be controlled in a variety of polymer nanocomposite systems to achieve required performance in a given application. The review will conclude by discussing potential obstacles to commercial uptake of polymer nanocomposites, such as inconsistent protocols to characterize nanocomposites, cost/performance balances, raw material availability, and emerging legislation, and will conclude by discussing the outlook for future development and commercial uptake of polymer nanocomposites. (review)

  13. Effect of thickness on microwave absorptive behavior of La-Na doped Co-Zr barium hexaferrites in 18.0–26.5 GHz band

    Energy Technology Data Exchange (ETDEWEB)

    Arora, Amit [D.A.V. Institute of Engineering and Technology, Jalandhar (India); Narang, Sukhleen Bindra, E-mail: sukhleen2@yahoo.com [Department of Electronics Technology, Guru Nanak Dev University, Amritsar (India); Pubby, Kunal [Department of Electronics Technology, Guru Nanak Dev University, Amritsar (India)

    2017-02-01

    In this research, the microwave properties of Lanthanum-Sodium doped Cobalt-Zirconium barium hexaferrites, intended as microwave absorbers, are analyzed on Vector Network Analyzer in K-band. The results indicate that the doping has resulted in lowering of real permittivity and enhancement of dielectric losses. Real permeability has shown increase while magnetic losses have shown decrease in value with doping. All these four properties have shown very small variation with frequency in the scanned frequency range which indicates the relaxation type of behavior. Microwave absorption characteristics of these compositions are analyzed with change in sample thickness. The results demonstrate that the matching frequency of the microwave absorber shifts towards lower side of frequency band with increase in thickness. The complete analysis of the prepared microwave absorbers shows a striking achievement with very low reflection loss and wide absorption bandwidth for all the six compositions in 18–26.5 GHz frequency band. - Highlights: • Electromagnetic Characterization of M-hexaferrites in K-band (18–26.5 GHz) • Variation of absorption properties with thickness of sample. • Satisfaction of quarter-wavelength condition for absorption properties • Results of double-layer absorbers (not reports till day by anyone).

  14. The Semi-Quantitative Study of Magnetization Process on Milling and Reannealing of Barium Hexaferrite (BaO.6Fe2O3

    Directory of Open Access Journals (Sweden)

    Ridwan

    2009-07-01

    Full Text Available Barium hexaferrite (BaO.6Fe2O3 is as a hard magnetic material with good chemical stability which has been intensively used as permanent magnet components. Many works have been done in order to improve their magnetic properties either through chemical process or powders metallurgy technique. In this work, commercial BaO.6Fe2O3 was milled using high-energy milling machine for 10, 20 and 30 hours and followed by reannealing for 3 hours at 1000⁰C in air. X-ray diffraction pattern indicate no phase decomposition occurred caused the mill processing, annealing of milled powders recovered the crystal system and promoted crystallite growth. The magnetic hysteresis curve measured by vibrating sample magnetometer (VSM shows the coercivity of annealed BaO.6Fe2O3 increases to two times higher than the original one. By using Jiles-Atherton model, all the hysteresis parameters Ms, k, α, a and c, have been determined adopted to the Genetic Algorithm (GA. The analyzed hysteretic parameters obtained from this work is congruent to the change of magnetic properties of as-milled and annealed powders of barium hexaferrite.

  15. Manufacture of barium hexaferrite (BaO3.98Fe2O3) from iron oxide waste of grinding process by using calcination process

    Science.gov (United States)

    Idayanti, N.; Dedi; Kristiantoro, T.; Mulyadi, D.; Sudrajat, N.; Alam, G. F. N.

    2018-03-01

    The utilization of iron oxide waste of grinding process as raw materials for making barium hexaferrite has been completed by powder metallurgy method. The iron oxide waste was purified by roasting at 800 °C temperature for 3 hours. The method used varying calcination temperature at 1000, 1100, 1200, and 1250 °C for 3 hours. The starting iron oxide waste (Fe2O3) and barium carbonate (BaCO3) were prepared by mol ratio of Fe2O3:BaCO3 from the formula BaO3.98Fe2O3. Some additives such as calcium oxide (CaO), silicon dioxide (SiO2), and polyvinyl alcohol (PVA) were added after calcination process. The samples were formed at the pressure of 2 ton/cm2 and sintered at the temperature of 1250 °C for 1 hour. The formation of barium hexaferrite compounds after calcination is determined by X-Ray diffraction. The magnetic properties were observed by Permagraph-Magnet Physik with the optimum characteristic at calcination temperature of 1250 °C with the induction of remanence (Br) = 1.38 kG, coercivity (HcJ) = 4.533 kOe, product energy maximum (BHmax) = 1.086 MGOe, and density = 4.33 g/cm3.

  16. Epitaxial growth of 100-μm thick M-type hexaferrite crystals on wide bandgap semiconductor GaN/Al{sub 2}O{sub 3} substrates

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Bolin; Su, Zhijuan; Bennett, Steve; Chen, Yajie, E-mail: y.chen@neu.edu; Harris, Vincent G. [Center for Microwave Magnetic Materials and Integrated Circuits and Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States)

    2014-05-07

    Thick barium hexaferrite BaFe{sub 12}O{sub 19} (BaM) films having thicknesses of ∼100 μm were epitaxially grown on GaN/Al{sub 2}O{sub 3} substrates from a molten-salt solution by vaporizing the solvent. X-ray diffraction measurement verified the growth of BaM (001) textured growth of thick films. Saturation magnetization, 4πM{sub s}, was measured for as-grown films to be 4.6 ± 0.2 kG and ferromagnetic resonance measurements revealed a microwave linewidth of ∼100 Oe at X-band. Scanning electron microscopy indicated clear hexagonal crystals distributed on the semiconductor substrate. These results demonstrate feasibility of growing M-type hexaferrite crystal films on wide bandgap semiconductor substrates by using a simple powder melting method. It also presents a potential pathway for the integration of ferrite microwave passive devices with active semiconductor circuit elements creating system-on-a-wafer architectures.

  17. Magneto-optical properties of BaCryFe12-yO19 (0.0 ≤ y ≤ 1.0) hexaferrites

    Science.gov (United States)

    Asiri, S.; Güner, S.; Korkmaz, A. D.; Amir, Md.; Batoo, K. M.; Almessiere, M. A.; Gungunes, H.; Sözeri, H.; Baykal, A.

    2018-04-01

    In this study, nanocrystalline BaCryFe12-yO19 (0.0 ≤ y ≤ 1.0) hexaferrite powders were prepared by sol-gel auto combustion method and the effect of Cr3+ ion substitution on morphology, structure, optic and magnetic properties of Barium hexaferrite were investigated. X-ray powder diffraction (XRD) analyses confirmed the purity of all samples. The XRD data shows that the average crystallite size lies between 60.95 nm and 50.10 nm and same was confirmed by Transmission electron microscopy. Transmission electron and scanning electron microscopy analyses presented the hexagonal morphology of all products. The characteristic hysteresis (σ-H) curves proved the ferromagnetic feature of as grown nanoparticle samples. Specific saturation magnetization (σs) drops from 46.59 to 34.89 emu/g with increasing Cr content while the coercive field values lie between 770 and 1652 Oe. The large magnitude of the magnetocrystalline (intrinsic) anisotropy field, (Ha) between 11.0 and 12.6 kOe proves that all products are magnetically hard. The energy band gap values decrease from 2.0 eV to 1.84 eV with increasing Cr content. From 57Fe Mössbauer spectroscopy, the variation in line width, isomer shift, quadrupole splitting and hyperfine magnetic field values were determined and discussed.

  18. Synthesis and magnetic properties of (Eu–Ni) substituted Y-type hexaferrite by surfactant assisted co-precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Irshad, E-mail: irshadalibzu@gmail.com [Department of Physics, BahauddinZakariya University, Multan, P.O# 60800 (Pakistan); Islam, M.U. [Department of Physics, BahauddinZakariya University, Multan, P.O# 60800 (Pakistan); Sadiq, Imran [Department of Physics, BahauddinZakariya University, Multan, P.O# 60800 (Pakistan); Centre of Excellence in Solid State Physics, University of The Punjab, Lahore (Pakistan); Karamat, Nazia [Institute of Chemical Science, Bahauddin Zakariya University, Multan 60800 (Pakistan); Iftikhar, Aisha [Department of Physics, BahauddinZakariya University, Multan, P.O# 60800 (Pakistan); Khan, M. Azhar [Department of Physics, Islamia University of Bahawalpur, 63100 Pakistan (Pakistan); Shah, Afzal [Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Athar, Muhammad [Institute of Chemical Science, Bahauddin Zakariya University, Multan 60800 (Pakistan); Shakir, Imran [Sustainable Energy Technologies (SET) Center, College of Engineering, King Saud University (Saudi Arabia); Ashiq, Muhammad Naeem, E-mail: naeemashiqqau@yahoo.com [Institute of Chemical Science, Bahauddin Zakariya University, Multan 60800 (Pakistan)

    2015-07-01

    A series of (Eu–Ni) substituted Y-type hexaferrite with composition Sr{sub 2}Co{sub (2−x)}Ni{sub x}Eu{sub y}Fe{sub (12−y)}O{sub 22} (x=0.0–1, Y=0.0–0.1) were prepared by the surfactant assisted co-precipitation method. The present samples were sintered at 1050 °C for 8 h. The shape of the particles is plate-like which is very advantageous for various applications and the grain size varies from 73 to 269 nm. The values of saturation magnetization (M{sub s}), remanent magnetization (M{sub r}) and magnetic moment (n{sub B}) were found to decrease which are attributed to the weakening of super exchange interactions. The values of in-plane Squareness ratios (M{sub r}/M{sub s}) ranging from 0.41 to 0.65 whereas in case of out of plane measurement it varies from 0.30 to 0.62.The investigated samples can be used in perpendicular recording media (PRM) due to high value of coercivity 2300 Oe which is analogous to the those of M-type and W-type hard magnetic. - Highlights: • The present samples sintered at 1050 °C for 8 h. • The grain size varies from 73 to 269 nm. • The magnetic moment varies from 15.27 to 6.07. • The shape of grains is plate like for microwave devices. • The present samples can be used in PRM due to high value of coercivity i.e. 2300 Oe.

  19. Quantum dots and nanocomposites.

    Science.gov (United States)

    Mansur, Herman Sander

    2010-01-01

    Quantum dots (QDs), also known as semiconducting nanoparticles, are promising zero-dimensional advanced materials because of their nanoscale size and because they can be engineered to suit particular applications such as nonlinear optical devices (NLO), electro-optical devices, and computing applications. QDs can be joined to polymers in order to produce nanocomposites which can be considered a scientific revolution of the 21st century. One of the fastest moving and most exciting interfaces of nanotechnology is the use of QDs in medicine, cell and molecular biology. Recent advances in nanomaterials have produced a new class of markers and probes by conjugating semiconductor QDs with biomolecules that have affinities for binding with selected biological structures. The nanoscale of QDs ensures that they do not scatter light at visible or longer wavelengths, which is important in order to minimize optical losses in practical applications. Moreover, at this scale, quantum confinement and surface effects become very important and therefore manipulation of the dot diameter or modification of its surface allows the properties of the dot to be controlled. Quantum confinement affects the absorption and emission of photons from the dot. Thus, the absorption edge of a material can be tuned by control of the particle size. This paper reviews developments in the myriad of possibilities for the use of semiconductor QDs associated with molecules producing novel hybrid nanocomposite systems for nanomedicine and bioengineering applications.

  20. Magnetoelectric Nanocomposites for Flexible Electronics

    KAUST Repository

    Al-Nassar, Mohammed Y.

    2015-01-01

    inside anodic aluminum oxide membranes is discussed. Characterization of electrodeposited iron, nickel and highly magnetostrictive iron-gallium alloy NWs was done using XRD, electron and magnetic force microscopy. Second, different nanocomposite films

  1. Magnetoelectric Nanocomposites for Flexible Electronics

    KAUST Repository

    Al-Nassar, Mohammed Y.

    2015-09-01

    Flexibility, low cost, versatility, miniaturization and multi-functionality are key aspects driving research and innovation in many branches of the electronics industry. With many anticipated emerging applications, like wearable, transparent and biocompatible devices, interest among the research community in pursuit for novel multifunctional miniaturized materials have been amplified. In this context, multiferroic polymer-based nanocomposites, possessing both ferroelectricity and ferromagnetism, are highly appealing. Most importantly, these nanocomposites possess tunable ferroelectric and ferromagnetic properties based on the parameters of their constituent materials as well as the magnetoelectric effect, which is the coupling between electric and magnetic properties. This tunability and interaction is a fascinating fundamental research field promising tremendous potential applications in sensors, actuators, data storage and energy harvesting. This dissertation work is devoted to the investigation of a new class of multiferroic polymer-based flexible nanocomposites, which exhibits excellent ferromagnetism and ferroelectricity simultaneously at room temperature, with the goal of understanding and optimizing the origin of their magnetoelectric coupling. The nanocomposites consist of high aspect ratio ferromagnetic nanowires (NWs) embedded inside a ferroelectric co-polymer, poly(vinylindene fluoride-trifluoroethylene), P(VDF-TrFE) matrix. First, electrochemical deposition of ferromagnetic NWs inside anodic aluminum oxide membranes is discussed. Characterization of electrodeposited iron, nickel and highly magnetostrictive iron-gallium alloy NWs was done using XRD, electron and magnetic force microscopy. Second, different nanocomposite films have been fabricated by means of spin coating and drop casting techniques. The effect of incorporation of NWs inside the ferroelectric polymer on its electroactive phase is discussed. The remanent and saturation polarization as well

  2. Magnetic Nanocomposite Cilia Sensors

    KAUST Repository

    Alfadhel, Ahmed

    2016-07-19

    Recent progress in the development of artificial skin concepts is a result of the increased demand for providing environment perception such as touch and flow sensing to robots, prosthetics and surgical tools. Tactile sensors are the essential components of artificial skins and attracted considerable attention that led to the development of different technologies for mimicking the complex sense of touch in humans. This dissertation work is devoted to the development of a bioinspired tactile sensing technology that imitates the extremely sensitive hair-like cilia receptors found in nature. The artificial cilia are fabricated from permanent magnetic, biocompatible and highly elastic nanocomposite material, and integrated on a giant magneto-impedance magnetic sensor to measure the stray field. A force that bends the cilia changes the stray field and is therefore detected with the magnetic sensor, providing high performance in terms of sensitivity, power consumption and versatility. The nanocomposite is made of Fe nanowires (NWs) incorporated into polydimethylsiloxane (PDMS). Fe NWs have a high remanent magnetization, due the shape anisotropy; thus, they are acting as permanent nano-magnets. This allows remote device operation and avoids the need for a magnetic field to magnetize the NWs, benefiting miniaturization and the possible range of applications. The magnetic properties of the nanocomposite can be easily tuned by modifying the NWs concentration or by aligning the NWs to define a magnetic anisotropy. Tactile sensors are realized on flexible and rigid substrates that can detect flow, vertical and shear forces statically and dynamically, with a high resolution and wide operating range. The advantage to operate the sensors in liquids and air has been utilized to measure flows in different fluids in a microfluidic channel. Various dynamic studies were conducted with the tactile sensor demonstrating the detection of moving objects or the texture of objects. Overall

  3. Magnetoelectric polymer nanocomposite for flexible electronics

    International Nuclear Information System (INIS)

    Alnassar, M.; Alfadhel, A.; Ivanov, Yu. P.; Kosel, J.

    2015-01-01

    This paper reports the fabrication and characterization of a new type of magnetoelectric polymer nanocomposite that exhibits excellent ferromagnetism and ferroelectricity simultaneously at room temperature. The multiferroic nanocomposite consists of high aspect ratio ferromagnetic iron nanowires embedded inside a ferroelectric co-polymer poly(vinylindene fluoride-trifluoroethylene), P(VDF-TrFE). The nanocomposite has been fabricated via a simple low temperature spin coating technique. Structural, ferromagnetic, ferroelectric, and magnetoelectric properties of the developed nanocomposite have been characterized. The nanocomposite films showed isotropic magnetic properties due to the random orientation of the iron nanowires inside the film. In addition, the embedded nanowires did not hinder the ferroelectric phase development of the nanocomposite. The developed nanocomposite showed a high magnetoelectric coupling response of 156 mV/cmOe measured at 3.1 kOe DC bias field. This value is among the highest reported magnetoelectric coupling in two phase particulate polymer nanocomposites

  4. Magnetoelectric polymer nanocomposite for flexible electronics

    KAUST Repository

    Al-Nassar, Mohammed Y.

    2015-03-06

    This paper reports the fabrication and characterization of a new type of magnetoelectric polymer nanocomposite that exhibits excellent ferromagnetism and ferroelectricity simultaneously at room temperature. The multiferroic nanocomposite consists of high aspect ratio ferromagnetic iron nanowires embedded inside a ferroelectric co-polymer poly(vinylindene fluoride-trifluoroethylene), P(VDF-TrFE). The nanocomposite has been fabricated via a simple low temperature spin coating technique. Structural, ferromagnetic, ferroelectric, and magnetoelectric properties of the developed nanocomposite have been characterized. The nanocomposite films showed isotropic magnetic properties due to the random orientation of the iron nanowires inside the film. In addition, the embedded nanowires did not hinder the ferroelectric phase development of the nanocomposite. The developed nanocomposite showed a high magnetoelectric coupling response of 156 mV/cmOe measured at 3.1 kOe DC bias field. This value is among the highest reported magnetoelectric coupling in two phase particulate polymer nanocomposites.

  5. Magnetoelectric polymer nanocomposite for flexible electronics

    KAUST Repository

    Al-Nassar, Mohammed Y.; Alfadhel, Ahmed; Ivanov, Yurii P.; Kosel, Jü rgen

    2015-01-01

    This paper reports the fabrication and characterization of a new type of magnetoelectric polymer nanocomposite that exhibits excellent ferromagnetism and ferroelectricity simultaneously at room temperature. The multiferroic nanocomposite consists of high aspect ratio ferromagnetic iron nanowires embedded inside a ferroelectric co-polymer poly(vinylindene fluoride-trifluoroethylene), P(VDF-TrFE). The nanocomposite has been fabricated via a simple low temperature spin coating technique. Structural, ferromagnetic, ferroelectric, and magnetoelectric properties of the developed nanocomposite have been characterized. The nanocomposite films showed isotropic magnetic properties due to the random orientation of the iron nanowires inside the film. In addition, the embedded nanowires did not hinder the ferroelectric phase development of the nanocomposite. The developed nanocomposite showed a high magnetoelectric coupling response of 156 mV/cmOe measured at 3.1 kOe DC bias field. This value is among the highest reported magnetoelectric coupling in two phase particulate polymer nanocomposites.

  6. Magneto-optical properties BaBi{sub x}La{sub x}Fe{sub 12−2x}O{sub 19} (0.0≤x≤0.5) hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Auwal, I.A. [Department of Chemistry, Fatih University, 34500 B.Çekmece, İstanbul (Turkey); Baykal, A., E-mail: hbaykal@fatih.edu.tr [Department of Chemistry, Fatih University, 34500 B.Çekmece, İstanbul (Turkey); Güner, S. [Department of Physics, Fatih University, 34500 B.Çekmece, İstanbul (Turkey); Sertkol, M. [Department of Physics Engineering, Istanbul Technical University, 34469 Maslak, Istanbul (Turkey); Sözeri, H. [TUBITAK-UME, National Metrology Institute, P.O. Box 54, 41470 Gebze, Kocaeli (Turkey)

    2016-07-01

    BaBi{sub x}La{sub x}Fe{sub (12−2x)}O{sub 19} (0.0≤x≤0.5) hexaferrites were synthesized by solid state synthesis route and the effects of Bi, La substitutions on structural, magnetic and optical properties were investigated. X-ray powder diffraction, Scanning electron microscopy, Vibrating sample magnetometer, and Percent diffuse reflectance spectroscopy were used to study the physical properties. Room temperature specific magnetization (M–H) curves revealed the ferromagnetic nature of all products. The increasing Bi, La compositions increased the magnetic properties at different magnitudes with respect to undoped BaFe{sub 12}O{sub 19} sample. The maximum values of remnant specific magnetization (M{sub r}=30.3 emu/g), extrapolated specific saturation magnetization (M{sub s}=62.12 emu/g), and magneton number (n{sub B}=16.27) were recorded from BaBi{sub 0.2}La{sub 0.2}Fe{sub 11.4}O{sub 19} hexaferrite. The average crystallite size varies in a range of (37.35–51.36) nm. The coercive field (H{sub c}) of undoped hexaferrites is 1180 Oe and increased to maximum 2320 Oe belonging to BaBi{sub 0.4}La{sub 0.4}Fe{sub 11.2}O{sub 19}. Magnetic anisotropy was confirmed as uniaxial and calculated effective anisotropy constants (K{sub eff}) are between 4.27×10{sup 5} Ergs/g and 5.05×10{sup 5} Ergs/g. The high magnitudes of magnetocrystalline anisotropy (H{sub a}) above than 16,200 Oe revealed that all samples are magnetically hard materials. The Tauc plots were drawn to extrapolate the direct optical energy band gap (E{sub g}) of hexaferrites. The E{sub g} values decreased from 1.76 eV to 1.47 eV with increasing Bi, La compositions. - Highlights: • BaBi{sub x}La{sub x}Fe{sub (12−2x)}O{sub 19} (0.0≤x≤0.5) hexaferrites were synthesized by solid state synthesis route. • The E{sub g} values decreased from 1.76 eV to 1.47 eV with increasing Bi, La compositions. • BaBi{sub xx}La{sub xx}Fe{sub 12-2x}O{sub 19} hexaferrites good candidate for potential applications

  7. CELLULOSIC NANOCOMPOSITES: A REVIEW

    Directory of Open Access Journals (Sweden)

    Martin A. Hubbe

    2008-08-01

    Full Text Available Because of their wide abundance, their renewable and environmentally benign nature, and their outstanding mechanical properties, a great deal of attention has been paid recently to cellulosic nanofibrillar structures as components in nanocomposites. A first major challenge has been to find efficient ways to liberate cellulosic fibrils from different source materials, including wood, agricultural residues, or bacterial cellulose. A second major challenge has involved the lack of compatibility of cellulosic surfaces with a variety of plastic materials. The water-swellable nature of cellulose, especially in its non-crystalline regions, also can be a concern in various composite materials. This review of recent work shows that considerable progress has been achieved in addressing these issues and that there is potential to use cellulosic nano-components in a wide range of high-tech applications.

  8. Graphene-aluminum nanocomposites

    International Nuclear Information System (INIS)

    Bartolucci, Stephen F.; Paras, Joseph; Rafiee, Mohammad A.; Rafiee, Javad; Lee, Sabrina; Kapoor, Deepak; Koratkar, Nikhil

    2011-01-01

    Highlights: → We investigated the mechanical properties of aluminum and aluminum nanocomposites. → Graphene composite had lower strength and hardness compared to nanotube reinforcement. → Processing causes aluminum carbide formation at graphene defects. → The carbides in between grains is a source of weakness and lowers tensile strength. - Abstract: Composites of graphene platelets and powdered aluminum were made using ball milling, hot isostatic pressing and extrusion. The mechanical properties and microstructure were studied using hardness and tensile tests, as well as electron microscopy, X-ray diffraction and differential scanning calorimetry. Compared to the pure aluminum and multi-walled carbon nanotube composites, the graphene-aluminum composite showed decreased strength and hardness. This is explained in the context of enhanced aluminum carbide formation with the graphene filler.

  9. A comparative study on the magnetic and electrical properties of MFe{sub 12}O{sub 19} (M=Ba and Sr)/BiFeO{sub 3} nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, M.A., E-mail: moala47@hotmail.com [Materials Science Lab (1), Physics Department, Faculty of Science, Cairo University, Giza (Egypt); Mansour, S.F. [Physics Department, Faculty of Science, Zagazig University (Egypt); Ismael, H. [Materials Science Lab (1), Physics Department, Faculty of Science, Cairo University, Giza (Egypt)

    2015-03-15

    M-type hexaferrite (MFe{sub 12}O{sub 19}), M=Ba or Sr nanoparticles with hexagonal crystal structure have been successfully synthesized by a citrate auto-combustion method. BiFeO{sub 3} (BFO) was prepared by the flash auto-combustion technique. Different nanocomposites were prepared according to the formula [(1−X) MFe{sub 12}O{sub 19}+XBiFeO{sub 3}; M=Ba or Sr, X=0.3, 0.4, 0.5 and 0.6]. The structure and morphology of the obtained nanocomposites have been determined by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). From the results, it is observed that the value of saturation magnetization decreases with increasing BFO content, which was mainly due to the contribution of the volume of the weak-magnetic BFO to the total sample volume. - Highlights: • M-type nanohexaferrite (MFe{sub 12}O{sub 19}) as M=Ba and Sr powders were synthesized by the citrate autocombustion method. • The lattice parameters of composite were negligibly smaller than those of M-type. • FESEM showed that the samples were hexagonal plate-like shape. • M{sub s}, M{sub r}, μ{sub eff.} and H{sub C} were improved to be suitable for perpendicular high density recording media. • ε′ increased with BFO ratio which is useful in microwave devices.

  10. Structural and magnetic properties of Nd–Mn substituted Y-type hexaferrites synthesized by microemulsion method

    International Nuclear Information System (INIS)

    Murtaza, G.; Ahmad, R.; Hussain, T.; Ayub, R.; Ali, Irshad; Khan, Muhammad Azhar; Akhtar, Majid Niaz

    2014-01-01

    Highlights: • Synthesis via a chemical route microemulsion method. • Samples were characterized with XRD, SEM, AFM, FTIR, Dielectric Measurements and VSM. • Single phase patterns were recorded. • A marked decrease in coercivity has been observed with the substitution of Nd–Mn. • These ferrites are suitable for multi-layer chip components in hyper-frequency. - Abstract: Nd–Mn substituted hexaferrites of composition Sr 2−x Nd x Ni 0.5 Co 1.5 Fe 12−y Mn y O 22 (x = 0.0, 0.02, 0.04, 0.06, 0.08, 0.10, 0.20, 0.30, y = 0.0, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75) were synthesized using microemulsion method. The synthesized materials are characterized using different techniques including X-ray diffraction (XRD), scanning electron microscopy(SEM), atomic force microscopy (AFM), Fourier transform Infrared spectroscopy (FTIR), Inductance capacitance resistance (LCR) meter and Vibrating sample magnetic magnetometer (VSM). For all samples, a single Y-type phase was established and the lattice constants have been calculated. XRD patterns reveal the significant increase in line broadening which indicates a decrease of grain size. The samples exhibit well defined crystallization; all of them are hexagonal platelet grains. With the increasing substitution level of Nd–Mn, the average grain diameter decreases. The dielectric constant ε ′ and dielectric loss factor ε″ are found to decrease initially with an increase in frequency and reached a constant value at higher frequency, exhibiting a frequency-independent behavior at higher frequencies. The dielectric loss tangent tanδ was found to decrease with an increase in the frequency. The H c decreases remarkably with increasing Nd and Mn ions content. It was found that the particle size could be effectively decreased and coercivity H c could easily be controlled by varying the concentration (x) without significantly decreasing saturation magnetization

  11. Structural and magnetic properties of Nd–Mn substituted Y-type hexaferrites synthesized by microemulsion method

    Energy Technology Data Exchange (ETDEWEB)

    Murtaza, G., E-mail: gm_rai786@yahoo.com [Centre for Advanced Studies in Physics, Government College University, Lahore 54000 (Pakistan); Ahmad, R.; Hussain, T.; Ayub, R. [Centre for Advanced Studies in Physics, Government College University, Lahore 54000 (Pakistan); Ali, Irshad [Department of Physics, Bahauddin Zakariya University, Multan (Pakistan); Khan, Muhammad Azhar [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Akhtar, Majid Niaz [Department of Physics, COMSATS Institute of Information Technology, Lahore 54000 (Pakistan)

    2014-07-25

    Highlights: • Synthesis via a chemical route microemulsion method. • Samples were characterized with XRD, SEM, AFM, FTIR, Dielectric Measurements and VSM. • Single phase patterns were recorded. • A marked decrease in coercivity has been observed with the substitution of Nd–Mn. • These ferrites are suitable for multi-layer chip components in hyper-frequency. - Abstract: Nd–Mn substituted hexaferrites of composition Sr{sub 2−x}Nd{sub x}Ni{sub 0.5}Co{sub 1.5}Fe{sub 12−y}Mn{sub y}O{sub 22} (x = 0.0, 0.02, 0.04, 0.06, 0.08, 0.10, 0.20, 0.30, y = 0.0, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75) were synthesized using microemulsion method. The synthesized materials are characterized using different techniques including X-ray diffraction (XRD), scanning electron microscopy(SEM), atomic force microscopy (AFM), Fourier transform Infrared spectroscopy (FTIR), Inductance capacitance resistance (LCR) meter and Vibrating sample magnetic magnetometer (VSM). For all samples, a single Y-type phase was established and the lattice constants have been calculated. XRD patterns reveal the significant increase in line broadening which indicates a decrease of grain size. The samples exhibit well defined crystallization; all of them are hexagonal platelet grains. With the increasing substitution level of Nd–Mn, the average grain diameter decreases. The dielectric constant ε{sup ′} and dielectric loss factor ε″ are found to decrease initially with an increase in frequency and reached a constant value at higher frequency, exhibiting a frequency-independent behavior at higher frequencies. The dielectric loss tangent tanδ was found to decrease with an increase in the frequency. The H{sub c} decreases remarkably with increasing Nd and Mn ions content. It was found that the particle size could be effectively decreased and coercivity H{sub c} could easily be controlled by varying the concentration (x) without significantly decreasing saturation magnetization.

  12. Biopolymeric nanocomposites with enhanced interphases.

    Science.gov (United States)

    Yin, Yi; Hu, Kesong; Grant, Anise M; Zhang, Yuhong; Tsukruk, Vladimir V

    2015-10-06

    Ultrathin and robust nanocomposite membranes were fabricated by incorporating graphene oxide (GO) sheets into a silk fibroin (SF) matrix by a dynamic spin-assisted layer-by-layer assembly (dSA-LbL). We observed that in contrast to traditional SA-LbL reported earlier fast solution removal during dropping of solution on constantly spinning substrates resulted in largely unfolded biomacromolecules with enhanced surface interactions and suppressed nanofibril formation. The resulting laminated nanocomposites possess outstanding mechanical properties, significantly exceeding those previously reported for conventional LbL films with similar composition. The tensile modulus reached extremely high values of 170 GPa, which have never been reported for graphene oxide-based nanocomposites, the ultimate strength was close to 300 MPa, and the toughness was above 3.4 MJ m(-3). The failure modes observed for these membranes suggested the self-reinforcing mechanism of adjacent graphene oxide sheets with strong 2 nm thick silk interphase composed mostly from individual backbones. This interphase reinforcement leads to the effective load transfer between the graphene oxide components in reinforced laminated nanocomposite materials with excellent mechanical strength that surpasses those known today for conventional flexible laminated carbon nanocomposites from graphene oxide and biopolymer components.

  13. Effect of annealing in reduced oxygen pressure on the structure and magnetic properties of M-type hexaferrite bulk and film

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Kyoung-Seok; Yang, Dae-Jin; Lee, Sang-Eui [Materials R& D Center, Samsung Advanced Institute of Technology, Samsung Electronics, 16677 Suwon (Korea, Republic of); Kim, Dong Hun [Department of Materials Science and Engineering, Myongji University, 17058 Yongin (Korea, Republic of); Kang, Young-Min, E-mail: ymkang@ut.ac.kr [Department of Materials Science & Engineering, Korea National University of Transportation, 27469 Chungju (Korea, Republic of)

    2017-06-15

    Highlights: • The Ca-La-Co SrM decomposed into the three different ferrite phases after N{sub 2} annealing at 1200 °C. • The charge-imbalance substitution of La{sup 3+}-Co{sup 2+} into SrM induces the phase instability. • The SrM films showed significantly increased M{sub S} with reduced H{sub C} after vacuum annealing. - Abstract: The Ca-La-Co-doped M-type Sr-hexaferrite (Sr{sub 0.1}Ca{sub 0.45}La{sub 0.45}Fe{sub 11.7}Co{sub 0.3}O{sub 19}) decomposed into three different phases of orthorhombic, spinel, and hexagonal structures after annealing at 1200 °C in nitrogen atmosphere while the non-substituted SrFe{sub 12}O{sub 19} maintained the hexagonal structure after annealing at the same condition. It is suggested that the charge-imbalance substitution of La{sup 3+}/Co{sup 2+} = 1.5 induces phase instability of the M-type structure and it causes the phase transformation during the N{sub 2} annealing. In film experiment, polycrystalline Sr-hexaferrite films (SrFe{sub 12}O{sub 19}) have been prepared by pulsed laser deposition and post-annealing processes. When the film was annealed in vacuum at 500 °C, the magnetization value at the magnetic field H = 15 kOe increased by ∼80% and the coercivity decreased significantly without microstructural change.

  14. Influence of La content on magnetic properties of Cu doped M-type strontium hexaferrite: Structural, magnetic, and Mossbauer spectroscopy study

    Science.gov (United States)

    Ghimire, M.; Yoon, S.; Wang, L.; Neupane, D.; Alam, J.; Mishra, S. R.

    2018-05-01

    The present study investigates the influence of Cu2+ and La3+-Cu2+ doping on the magnetic properties of Sr1-xLaxFe12-xCuxO19 (x = 0.0-0.5) hexaferrite (SrM) compounds. The samples were prepared via facile autocombustion technique followed by sintering. X-ray powder diffraction patterns show the formation of the pure phase of M-type hexaferrite for all x. Invariance in lattice parameters was observed with only Cu2+ substitution while lattice contraction along c-axis was observed with co-doping La3+-Cu2+ in SrM. The magnetic property of these compounds is explained based on Cu2+ occupancy in the absence and presence of La3+ in SrM magnetoplumbite structure. The Cu2+ doped SrFe12-xCuxO19 sample showed a monotonic decrease in Ms value while La3+-Cu2+ showed a noticeable increase in Ms value with x. Furthermore, while coercivity of Cu2+ doped SrM reduced with x, the coercivity of La3+-Cu2+ doped SrM showed a marked 12% increase in coercivity at x = 0.1 (Hc = 4391 Oe) from that of x = 0.0 (3918 Oe). Interestingly, Cu2+ doped SrM displayed invariance in Tc ∼ 458.6 °C with x, while La3+-Cu2+ doping reduced Tc by 5% from its x = 0 (Tc = 451.9 °C) to 429.6 °C. The room temperature Mossbauer spectral analysis confirmed a Cu2+ preference for the 12k site and its occupancy is observed to be influenced by the presence of La3+ ion at the Sr2+ site.

  15. Experimental analysis of graphene nanocomposite on Kevlar

    Science.gov (United States)

    Manigandan, S.; Gunasekar, P.; Nithya, S.; Durga Revanth, G.; Anudeep, A. V. S. C.

    2017-08-01

    Graphene nanocomposite is a two dimensional structure which has intense role in material science. This paper investigates the topological property of the graphene nanocomposite doped in Kevlar fiber by direct mixing process. The Kevlar fiber by direct mixing process. The Kevlar fiber taken as the specimen which is fabricated by vacuum bag moulding process. Epoxy used as resin and HY951 as hardener. Three different specimens are fabricated based on the percentage of graphene nanocomposite 2%, 5%, 10% and 20% respectively. We witnessed the strength of the Kevlar fiber is increased when it is treated with nanocomposite. The percentage of the nanocomposite increase the strength of the fiber is increased. However as the nanocomposite beyond 5% the strength of fiber is dropped. In addition, we also seen the interfacial property of the fiber is dropped when the nanocomposite is added beyond threshold limit.

  16. Effect of calcination temperature on microstructure, dielectric, magnetic and optical properties of Ba0.7La0.3Fe11.7Co0.3O19 hexaferrites

    International Nuclear Information System (INIS)

    Kaur, Talwinder; Kaur, Barjinder; Bhat, Bilal H.; Kumar, Sachin; Srivastava, A.K.

    2015-01-01

    M-type barium hexaferrite Ba 0.7 La 0.3 Fe 11.7 Co 0.3 O 19 (BaLCM) powder, synthesized using sol gel auto combustion method, heat treated at 700, 900, 1100 and 1200 °C. X ray diffraction (XRD) powder patterns of heat treated samples show the formation of pure phase of M-type hexaferrite after 700 °C. Thermo gravimetric analysis (TGA) reveals that the weight loss of BaLCM becomes constant after 680 °C. The presence of two prominent peaks, at 432 cm −1 and 586 cm −1 in Fourier Transform Infrared Spectroscopy (FT-IR) spectra, gives the idea of formation of M-type hexaferrites. The M–H curve obtained from Vibrating Sample Magnetometer (VSM) were used to calculate saturation magnetization (M S ), retentivity (M r ), squareness ration (SR) and coercivity (H c ). The maximum value of coercivity (5602 Oe) is found at 900 °C. The band gap dependency on temperature was studied using UV–vis NIR spectroscopy. The dielectric constant has been found to be high at low frequency but it decreases with increase in frequency. Such kind of dielectric behavior is explained on the basis of Koop's phenomenological theory and Maxwell Wagner theory

  17. Aerogel nanocomposite materials

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, A.J.; Ayers, M.; Cao, W. [Lawrence Berkeley Laboratory, CA (United States)] [and others

    1995-05-01

    Aerogels are porous, low density, nanostructured solids with many unusual properties including very low thermal conductivity, good transparency, high surface area, catalytic activity, and low sound velocity. This research is directed toward developing new nanocomposite aerogel materials for improved thermal insulation and several other applications. A major focus of the research has been to further increase the thermal resistance of silica aerogel by introducing infrared opacification agents into the aerogel to produce a superinsulating composite material. Opacified superinsulating aerogel permit a number of industrial applications for aerogel-based insulation. The primary benefits from this recently developed superinsulating composite aerogel insulation are: to extend the range of applications to higher temperatures, to provide a more compact insulation for space sensitive-applications, and to lower costs of aerogel by as much as 30%. Superinsulating aerogels can replace existing CFC-containing polyurethane in low temperature applications to reduce heat losses in piping, improve the thermal efficiency of refrigeration systems, and reduce energy losses in a variety of industrial applications. Enhanced aerogel insulation can also replace steam and process pipe insulation in higher temperature applications to substantially reduce energy losses and provide much more compact insulation.

  18. Stretchable piezoelectric nanocomposite generator.

    Science.gov (United States)

    Park, Kwi-Il; Jeong, Chang Kyu; Kim, Na Kyung; Lee, Keon Jae

    2016-01-01

    Piezoelectric energy conversion that generate electric energy from ambient mechanical and vibrational movements is promising energy harvesting technology because it can use more accessible energy resources than other renewable natural energy. In particular, flexible and stretchable piezoelectric energy harvesters which can harvest the tiny biomechanical motions inside human body into electricity properly facilitate not only the self-powered energy system for flexible and wearable electronics but also sensitive piezoelectric sensors for motion detectors and in vivo diagnosis kits. Since the piezoelectric ZnO nanowires (NWs)-based energy harvesters (nanogenerators) were proposed in 2006, many researchers have attempted the nanogenerator by using the various fabrication process such as nanowire growth, electrospinning, and transfer techniques with piezoelectric materials including polyvinylidene fluoride (PVDF) polymer and perovskite ceramics. In 2012, the composite-based nanogenerators were developed using simple, low-cost, and scalable methods to overcome the significant issues with previously-reported energy harvester, such as insufficient output performance and size limitation. This review paper provides a brief overview of flexible and stretchable piezoelectric nanocomposite generator for realizing the self-powered energy system with development history, power performance, and applications.

  19. Metal oxide/polyaniline nanocomposites

    Indian Academy of Sciences (India)

    Nanocomposites of iron oxide with conducting polymer in the form of powders of varying compositions have been studied to understand the effects of particle size, cluster size and magnetic inter-particle interactions. The sizes of the nanoparticles were estimated to be ∼ 10–20 nm from the X-ray diffraction (XRD) and the ...

  20. Nanocomposites with biodegradable polycaprolactone matrix

    Czech Academy of Sciences Publication Activity Database

    Janigová, I.; Lednický, František; Jochec-Mošková, D.; Chodák, I.

    2011-01-01

    Roč. 301, č. 1 (2011), s. 1-8 ISSN 1022-1360. [Eurofillers /8./. Alessandria, 21.06.2009-25.06.2009] Institutional research plan: CEZ:AV0Z40500505 Keywords : melt mixing * nanocomposite s * organoclay Subject RIV: CD - Macromolecular Chemistry

  1. Magnetic Nanocomposite Cilia Tactile Sensor

    KAUST Repository

    Alfadhel, Ahmed; Kosel, Jü rgen

    2015-01-01

    A multifunctional biomimetic nanocomposite tactile sensor is developed that can detect shear and vertical forces, feel texture, and measure flow with extremely low power consumption. The sensor's high performance is maintained within a wide operating range that can be easily adjusted. The concept works on rigid and flexible substrates and the sensors can be used in air or water without any modifications.

  2. Magnetic Nanocomposite Cilia Tactile Sensor

    KAUST Repository

    Alfadhel, Ahmed

    2015-10-21

    A multifunctional biomimetic nanocomposite tactile sensor is developed that can detect shear and vertical forces, feel texture, and measure flow with extremely low power consumption. The sensor\\'s high performance is maintained within a wide operating range that can be easily adjusted. The concept works on rigid and flexible substrates and the sensors can be used in air or water without any modifications.

  3. How Nano are Nanocomposites (Preprint)

    National Research Council Canada - National Science Library

    Schafer, Dale W; Justice, Ryan S

    2007-01-01

    ...s (single and multi-walled), and layered silicates. The conclusion is that large-scale disorder is ubiquitous in nanocomposites regardless of the level of dispersion, leading to substantial reduction of mechanical properties (modulus) compared to predictions based on idealized filler morphology.

  4. Formation of Silver and Gold Dendrimer Nanocomposites

    International Nuclear Information System (INIS)

    Balogh, Lajos; Valluzzi, Regina; Laverdure, Kenneth S.; Gido, Samuel P.; Hagnauer, Gary L.; Tomalia, Donald A.

    1999-01-01

    Structural types of dendrimer nanocomposites have been studied and the respective formation mechanisms have been described, with illustration of nanocomposites formed from poly(amidoamine) PAMAM dendrimers and zerovalent metals, such as gold and silver. Structure of {(Au(0)) n- PAMAM} and {(Ag(0)) n- PAMAM} gold and silver dendrimer nanocomposites was found to be the function of the dendrimer structure and surface groups as well as the formation mechanism and the chemistry involved. Three different types of single nanocomposite architectures have been identified, such as internal ('I'), external ('E') and mixed ('M') type nanocomposites. Both the organic and inorganic phase could form nanosized pseudo-continuous phases while the other components are dispersed at the molecular or atomic level either in the interior or on the surface of the template/container. Single units of these nanocomposites may be used as building blocks in the synthesis of nanostructured materials

  5. Method to produce catalytically active nanocomposite coatings

    Science.gov (United States)

    Erdemir, Ali; Eryilmaz, Osman Levent; Urgen, Mustafa; Kazmanli, Kursat

    2016-02-09

    A nanocomposite coating and method of making and using the coating. The nanocomposite coating is disposed on a base material, such as a metal or ceramic; and the nanocomposite consists essentially of a matrix of an alloy selected from the group of Cu, Ni, Pd, Pt and Re which are catalytically active for cracking of carbon bonds in oils and greases and a grain structure selected from the group of borides, carbides and nitrides.

  6. Epoxy polyurethane nanocomposites filled with fullerite

    International Nuclear Information System (INIS)

    Rozhnova, R.A.; Galatenko, N.A.; Lukashevich, S.A.; Shirokov, O.D.; Levenets', Je.G.

    2015-01-01

    New nanocomposite materials based on epoxy polyurethane (EPU) containing nanoscale fullerite in its composition are produced. The influence of small impurities of fullerite on physical and mechanical properties of the nanocomposites is established. The effect of a nanofiller and its concentration on the structure and properties of the composite and the ability to biodegradation in vitro is studied. The developed nanocomposites exhibit the biodegradability, and the presence of nanofillers in the EPU facilitates the course of the process

  7. Fracture behavior of polypropylene/clay nanocomposites.

    Science.gov (United States)

    Chen, Ling; Wang, Ke; Kotaki, Masaya; Hu, Charmaine; He, Chaobin

    2006-12-01

    Polypropylene (PP)/clay nanocomposites have been prepared via a reactive compounding approach with an epoxy based masterbatch. Compared with PP and common PP/organoclay nanocomposites, the PP/clay nanocomposites based on epoxy/clay masterbatch have higher impact strength. The phenomenon can be attributed to the epoxy phase dispersed uniformly in the PP matrix, which may act as impact energy absorber and helps to form a large damage zone, thus a higher impact strength value is achieved.

  8. Method to produce catalytically active nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, Ali; Eryilmaz, Osman Levent; Urgen, Mustafa; Kazmanli, Kursat

    2017-12-19

    A nanocomposite coating and method of making and using the coating. The nanocomposite coating is disposed on a base material, such as a metal or ceramic; and the nanocomposite consists essentially of a matrix of an alloy selected from the group of Cu, Ni, Pd, Pt and Re which are catalytically active for cracking of carbon bonds in oils and greases and a grain structure selected from the group of borides, carbides and nitrides.

  9. nanocomposites chitosan /clay for electrochemical sensors

    International Nuclear Information System (INIS)

    Braga, Carla R. Costa; Melo, Frank M. Araujo de; Costa, Gilmara M. Silva; Silva, Suedina M. Lima

    2009-01-01

    This study was performed to obtain films of nanocomposites chitosan/bentonite and chitosan/montmorillonite intercalation by the technique of solution in the proportions of 5:1 and 10:1. The nanocomposites were characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD) and the nanocomposites Chitosan/montmorillonite also were characterized by thermogravimetric analysis (TG). The results indicated that the feasibility of obtaining films of nanocomposites exfoliate. Among the suggested applications for films developed in this study includes them use for electrochemical sensors. (author)

  10. Nanocomposite polymer electrolyte based on whisker or microfibrils polyoxyethylene nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Alloin, Fannie, E-mail: fannie.alloin@lepmi.grenoble-inp.f [LEPMI, Laboratoire d' Electrochimie et de Physicochimie des Materiaux et des Interfaces, Grenoble-INP-UJF-CNRS, UMR 5631, BP 75, 38041 Grenoble Cedex 9 (France); D' Aprea, Alessandra [Laboratoire de Rheologie, Grenoble-INP-UJF, UMR 5520, BP 53, 38041 Grenoble Cedex 9 (France); LEPMI, Laboratoire d' Electrochimie et de Physicochimie des Materiaux et des Interfaces, Grenoble-INP-UJF-CNRS, UMR 5631, BP 75, 38041 Grenoble Cedex 9 (France); Ecole Internationale du Papier, de la communication imprimee et des Biomateriaux, PAGORA- Grenoble-INP, BP 65, 38402 Saint Martin d' Heres Cedex (France); Kissi, Nadia El [Laboratoire de Rheologie, Grenoble-INP-UJF, UMR 5520, BP 53, 38041 Grenoble Cedex 9 (France); Dufresne, Alain [Ecole Internationale du Papier, de la communication imprimee et des Biomateriaux, PAGORA- Grenoble-INP, BP 65, 38402 Saint Martin d' Heres Cedex (France); Bossard, Frederic [Laboratoire de Rheologie, Grenoble-INP-UJF, UMR 5520, BP 53, 38041 Grenoble Cedex 9 (France)

    2010-07-15

    Nanocomposite polymer electrolytes composed of high molecular weight poly(oxyethylene) PEO as a matrix, LiTFSI as lithium salt and ramie, cotton and sisal whiskers with high aspect ratio and sisal microfibrils (MF), as reinforcing phase were prepared by casting-evaporation. The morphology of the composite electrolytes was investigated by scanning electron microscopy and their thermal behavior (characteristic temperatures, degradation temperature) were investigated by thermogravimetric analysis and differential scanning calorimetry. Nanocomposite electrolytes based on PEO reinforced by whiskers and MF sisal exhibited very high mechanical performance with a storage modulus of 160 MPa at high temperature. A weak decrease of the ionic conductivity was observed with the incorporation of 6 wt% of whiskers. The addition of microfibrils involved a larger decrease of the conductivity. This difference may be associated to the more restricted PEO mobility due to the addition of entangled nanofibers.

  11. Modulation of electromagnetic and absorption properties in 18-26.5 GHz frequency range of strontium hexaferrites with doping of cobalt-zirconium

    Science.gov (United States)

    Pubby, Kunal; Narang, Sukhleen Bindra; Kaur, Prabhjyot; Chawla, S. K.

    2017-05-01

    Hexaferrite nano-particles of stoichiometric composition {{Sr}}{({{CoZr}})_x}{{F}}{{{e}}_{12 - 2x}}{{{O}}_{19}}, with x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 were prepared using sol-gel auto-combustion route owing to its advantages such as low sintering temperature requirement, homogeneity and uniformity of grains. Tartaric acid as a fuel was utilized to complete the chemical reaction. The goal of this study is to analyse the effect of co-substitution of cobalt and zirconium on the electromagnetic and absorption properties of pure {{SrF}}{{{e}}_{12}}{{{O}}_{19}} hexaferrite. The properties were measured on the rectangular pellets of thickness 2.5 mm for K-frequency band using Vector Network Analyzer. The doping of Co-Zr has resulted in increase in real as well as imaginary parts of permittivity. The values of real permittivity lie in the range 3.6-7.0 for all the composition. The real part of permeability remains in range 0.7-1.6 in the studied frequency band for all the samples and shows slightly increasing trend with frequency. The maximum values of dielectric loss tangent peak (3.04) and magnetic loss tangent peak (2.34), among all the prepared compositions, have been observed for composition x = 0.2. Compositions with x = 0.6 and x = 0.0 also have high dielectric and magnetic loss peaks. Dielectric loss peaks are attributed to dielectric resonance and magnetic loss peaks are attributed to natural resonance. Experimentally determined reflection loss results show that all six compositions of prepared series have high values of absorption to propose them as single-layer absorbers in 18-26.5 GHz frequency range. The composition with x = 0.2 has maximum absorption capacity with reflection loss peak of -37.2 dB at 24.3 GHz frequency. The undoped composition also has high absorption peak (-25.46 dB), but -10 dB absorption bandwidth is minimum (2.2 GHz) out of the present series. Maximum absorption bandwidth is obtained for x = 1.0 (4.1 GHz). Other doped compositions also

  12. Structural, magnetic and microwave absorption behavior of Co-Zr substituted strontium hexaferrites prepared using tartaric acid fuel for electromagnetic interference suppression

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Prabhjyot, E-mail: prabhjyot.2525@gmail.com [Department of Chemistry, Centre for Advanced Studies-I, Guru Nanak Dev University, Amritsar 143005 (India); Chawla, S.K., E-mail: sschawla118@gmail.com [Department of Chemistry, Centre for Advanced Studies-I, Guru Nanak Dev University, Amritsar 143005 (India); Narang, Sukhleen Bindra, E-mail: sukhleen2@yahoo.com [Department of Electronics Technology, Guru Nanak Dev University, Amritsar 143005 (India); Pubby, Kunal, E-mail: kunalpubby02@gmail.com [Department of Electronics Technology, Guru Nanak Dev University, Amritsar 143005 (India)

    2017-01-15

    Strontium hexaferrites, doped with varying Co-Zr content (x) have been synthesized by sol-gel auto-combustion route using tartaric acid as fuel at 800 °C. X-ray diffraction and Fourier transform Infra-red have been carried out to confirm the phase formation, particle size (average 21.9–36.8 nm) and the bond formation respectively. Magnetic properties are scrutinized using vibrating sample magnetometer. Techniques like scanning electron microscopy, transmission electron microscopy and energy dispersive scattering have been employed to explore the surface morphology, particle size and composition of the nano-powders. Electromagnetic characterization of the prepared ferrites has been done using Vector Network Anlyzer in 12.4–18 GHz frequency range. The effect of calcination temperature (500–1000 °C) on the structure, morphology and magnetic properties has also been studied for x=0.2 and 800 °C has been found to be the most suitable temperature with the best magnetic properties. Increase in doping has resulted in resonance peaks in dielectric and magnetic loss spectra, leading to microwave absorption peaks. Ferrites with x=0.2, 0.8 and 1.0 have appropriate reflection loss less than −10 dB and bandwidth in Ku-band, hence can be used as effective absorbers in suppression of electromagnetic interference (EMI). The governance of impedance matching in deciding the absorption properties has been proved by using input impedance calculations. - Highlights: • Co-Zr doped strontium hexaferrite nanopowders have been prepared by sol-gel route. • 800 °C was most suitable temperaturewith best structural and magnetic properties. • Samples have M-type hexagonal structure with an average particle size of 36.47 nm. • Samples x=0.2, 0.8 and 1.0 are suitable for suppression of EM waves in Ku-band. • The origin of absorption peaks: impedance matching and losses has been explained.

  13. Effects of La{sup 3+}-Zn{sup 2+} doping on the structure, magnetic, electrical, and dielectric properties of low temperature sintered Sr-hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Long, E-mail: penglong@cuit.edu.cn [Sichuan Province Key Laboratory of Information Materials and Devices Application, College of Optoelectronic Technology, Chengdu University of Information Technology, Chengdu 610225 (China); Li, Lezhong; Zhong, Xiaoxi [Sichuan Province Key Laboratory of Information Materials and Devices Application, College of Optoelectronic Technology, Chengdu University of Information Technology, Chengdu 610225 (China); Hu, Yuebin [Chengdu Industrial Vocational and Technical College, Chengdu 610213 (China); Chen, Sanming [Sichuan Province Key Laboratory of Information Materials and Devices Application, College of Optoelectronic Technology, Chengdu University of Information Technology, Chengdu 610225 (China)

    2017-04-15

    The Sr{sub 1-x}La{sub x}Fe{sub 12-x}Zn{sub x}O{sub 19} (x=0–0.3) hexaferrites with Bi{sub 2}O{sub 3} additive were prepared by microwave sintering method at low sintering temperatures, and their crystal structure, microstructure, magnetic, electrical, and dielectric properties were studied. The results show that the pure M-type phase is obtained for the ferrites with x≤0.2. With x further increasing to 0.3, the multiphase structure is inevitably formed, where the LaFeO{sub 3} phase coexists with the M-type phase. In the single phase region, the varied magnetic, electrical, and dielectric properties with La{sup 3+}-Zn{sup 2+} doping amount are well explained by the occupancy effects of La{sup 3+} and Zn{sup 2+} in magnetoplumbite structure. It is suggested that the Zn{sup 2+} ions replace the Fe{sup 3+} ions at 4f{sub 1} site with x≤0.15, but the substitution of Zn{sup 2+} for Fe{sup 3+} occurs at 2b site preferentially when the La{sup 3+}-Zn{sup 2+} doping amount exceeds 0.15. - Highlights: • The low temperature sintered Sr{sub 1-x}La{sub x}Fe{sub 12-x}Zn{sub x}O{sub 19} (x=0–0.3) hexaferrites are successfully prepared. • The La{sup 3+}-Zn{sup 2+} ions partially substitute the Sr{sup 2+}-Fe{sup 3+} ions in a doping region of x≤0.2. • Effects of La{sup 3+}-Zn{sup 2+} doping on the magnetic, electrical and polarization properties are revealed. • The substitution of Zn{sup 2+} for Fe{sup 3+} occurs at 4f{sub 1} site and 2b site before and after x=0.15, respectively.

  14. Modulation of electromagnetic and absorption properties in 18-26.5 GHz frequency range of strontium hexaferrites with doping of cobalt-zirconium

    Energy Technology Data Exchange (ETDEWEB)

    Pubby, Kunal; Narang, Sukhleen Bindra [Guru Nanak Dev University, Department of Electronics Technology, Amritsar (India); Kaur, Prabhjyot; Chawla, S.K. [Guru Nanak Dev University, Department of Chemistry, Centre for Advanced Studies-I, Amritsar (India)

    2017-05-15

    Hexaferrite nano-particles of stoichiometric composition Sr(CoZr){sub x}Fe{sub 12-2x}O{sub 19}, with x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 were prepared using sol-gel auto-combustion route owing to its advantages such as low sintering temperature requirement, homogeneity and uniformity of grains. Tartaric acid as a fuel was utilized to complete the chemical reaction. The goal of this study is to analyse the effect of co-substitution of cobalt and zirconium on the electromagnetic and absorption properties of pure SrFe{sub 12}O{sub 19} hexaferrite. The properties were measured on the rectangular pellets of thickness 2.5 mm for K-frequency band using Vector Network Analyzer. The doping of Co-Zr has resulted in increase in real as well as imaginary parts of permittivity. The values of real permittivity lie in the range 3.6-7.0 for all the composition. The real part of permeability remains in range 0.7-1.6 in the studied frequency band for all the samples and shows slightly increasing trend with frequency. The maximum values of dielectric loss tangent peak (3.04) and magnetic loss tangent peak (2.34), among all the prepared compositions, have been observed for composition x = 0.2. Compositions with x = 0.6 and x = 0.0 also have high dielectric and magnetic loss peaks. Dielectric loss peaks are attributed to dielectric resonance and magnetic loss peaks are attributed to natural resonance. Experimentally determined reflection loss results show that all six compositions of prepared series have high values of absorption to propose them as single-layer absorbers in 18-26.5 GHz frequency range. The composition with x = 0.2 has maximum absorption capacity with reflection loss peak of -37.2 dB at 24.3 GHz frequency. The undoped composition also has high absorption peak (-25.46 dB), but -10 dB absorption bandwidth is minimum (2.2 GHz) out of the present series. Maximum absorption bandwidth is obtained for x = 1.0 (4.1 GHz). Other doped compositions also have high absorption bandwidth

  15. Polymer-Layer Silicate Nanocomposites

    DEFF Research Database (Denmark)

    Potarniche, Catalina-Gabriela

    Nowadays, some of the material challenges arise from a performance point of view as well as from recycling and biodegradability. Concerning these aspects, the development of polymer layered silicate nanocomposites can provide possible solutions. This study investigates how to obtain polymer layered...... with a spectacular improvement up to 300 % in impact strength were obtained. In the second part of this study, layered silicate bio-nanomaterials were obtained starting from natural compounds and taking into consideration their biocompatibility properties. These new materials may be used for drug delivery systems...... and as biomaterials due to their high biocompatible properties, and because they have the advantage of being biodegradable. The intercalation process of natural compounds within silicate platelets was investigated. By uniform dispersing of binary nanohybrids in a collagen matrix, nanocomposites with intercalated...

  16. Targeted delivery of polyoxometalate nanocomposites.

    Science.gov (United States)

    Geisberger, Georg; Paulus, Susann; Gyenge, Emina Besic; Maake, Caroline; Patzke, Greta R

    2011-10-04

    Polyoxometalate/carboxymethyl chitosan nanocomposites with an average diameter of 130 nm are synthesized and labeled with fluorescein isothiocyanate (FITC) for a combined drug-carrier and cellular-monitoring approach. [Eu(β(2) -SiW(11) O(39) )(2) ](13-) /CMC nanospheres as a representative example do not display cytotoxicity for POM concentrations up to 2 mg mL(-1) . Cellular uptake of fluoresecently labelled {EuSiW(11) O(39) }/FITC-CMC nanoparticles is monitored with confocal laser scanning microscopy. Nanoparticle uptake occurs after incubation times of around 1 h and no cyctotoxic effects are observed upon prolonged treatment. The preferential location of the POM/CMC nanocomposites in the perinuclear region is furthermore verified with transmission electron microscopy investigations on unlabeled nanoparticles. Therefore, this approach is a promising dual strategy for the safe cellular transfer and monitoring of bioactive POMs. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Magnetic Nanocomposite Cilia Energy Harvester

    KAUST Repository

    Khan, Mohammed Asadullah

    2016-02-11

    An energy harvester capable of converting low frequency vibrations into electrical energy is presented. The operating principle, fabrication process and output characteristics at different frequencies are discussed. The harvester is realized by fabricating an array of polydimethylsiloxane (PDMS) - iron nanowire nanocomposite cilia on a planar coil array. Each coil element consists of 14 turns and occupies an area of 600 μm x 600μm. The cilia are arranged in a 12x5 array and each cilium is 250 μm wide and 2 mm long. The magnetic characteristics of the fabricated cilia indicate that the nanowires are well aligned inside of the nanocomposite, increasing the efficiency of energy harvesting. The energy harvester occupies an area of 66.96 mm2 and produces an output r.m.s voltage of 206.47μV, when excited by a 40 Hz vibration of 1 mm amplitude.

  18. Colloidal QDs-polymer nanocomposites

    Science.gov (United States)

    Gordillo, H.; Suárez, I.; Rodríguez-Cantó, P.; Abargues, R.; García-Calzada, R.; Chyrvony, V.; Albert, S.; Martínez-Pastor, J.

    2012-04-01

    Nanometer-size colloidal semiconductor nanocrystals, or Quantum Dots (NQD), are very prospective active centers because their light emission is highly efficient and temperature-independent. Nanocomposites based on the incorporation of QDs inside a polymer matrix are very promising materials for application in future photonic devices because they combine the properties of QDs with the technological feasibility of polymers. In the present work some basic applications of these new materials have been studied. Firstly, the fabrication of planar and linear waveguides based on the incorporation of CdS, CdSe and CdTe in PMMA and SU-8 are demonstrated. As a result, photoluminescence (PL) of the QDs are coupled to a waveguide mode, being it able to obtain multicolor waveguiding. Secondly, nanocomposite films have been evaluated as photon energy down-shifting converters to improve the efficiency of solar cells.

  19. Bitumen nanocomposites with improved performance

    KAUST Repository

    Kosma, Vasiliki

    2017-11-29

    Bitumen-clay nanocomposite binders with styrene-butadienestyrene triblock copolymer, SBS, and combinations of SBS and crumb rubber (CR) with different CR/SBS ratios have been synthesized and characterized. In addition to the binder, samples containing the binder and concrete sand (with a weight ratio 1:9) were prepared. The modified binders were studied in terms of filler dispersion, storage stability, mechanical performance and water susceptibility. We demonstrate that the samples containing nanoclays consistently outperform those based only on the polymer additives. We also find that nanocomposite samples based on a combination of SBS and CR are best, since in addition to other improvements they show excellent storage stability. Our work shows that substituting CR with SBS as a bitumen additive and combining it with inexpensive nanoclays leads to new materials with enhanced performance and improved stability for practical asphalt applications.

  20. Electrospun Borneol-PVP Nanocomposites

    Directory of Open Access Journals (Sweden)

    Xiao-Yan Li

    2012-01-01

    Full Text Available The present work investigates the validity of electrospun borneol-polyvinylpyrrolidone (PVP nanocomposites in enhancing drug dissolution rates and improving drug physical stability. Based on hydrogen bonding interactions and via an electrospinning process, borneol and PVP can form stable nanofiber-based composites. FESEM observations demonstrate that composite nanofibers with uniform structure could be generated with a high content of borneol up to 33.3% (w/w. Borneol is well distributed in the PVP matrix molecularly to form the amorphous composites, as verified by DSC and XRD results. The composites can both enhance the dissolution profiles of borneol and increase its physical stability against sublimation for long-time storage by immobilization of borneol molecules with PVP. The incorporation of borneol in the PVP matrix weakens the tensile properties of nanofibers, and the mechanism is discussed. Electrospun nanocomposites can be alternative candidates for developing novel nano-drug delivery systems with high performance.

  1. Radiolytic Synthesis of Magnetic Nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Grdanovska, Slavica; Tissot, Chanel; Barkatt, Aaron; Al-Sheikhly, Mohamad [Nuclear Engineering Program – Department of Materials Science and Engineering, University of Maryland, College Park, MD (United States)

    2011-07-01

    Magnetic nanocomposites, in which magnetic nanoparticles are encapsulated in polymeric matrices, have important applications in medicine, electronics and mechanical devices. However, the development of processes leading to magnetic nanocomposites with desirable, predictable and reproducible properties has turned out to be a difficult challenge. To date, most studies have concentrated on a magnetic oxide, primarily magnetite (Fe{sub 3}O{sub 4}), as the encapsulated phase. However, the synthesis of batches of magnetite with homogeneous properties at reasonably low temperature is a delicate operation. Indeed, commercial lots of magnetite powder, despite having bulk Fe{sub 3}O{sub 4} stoichiometry, turn out to have large variations in structure and in magnetic properties. The difficulties in controlling the product are greatly magnified when the particle size is in the nanometer range.

  2. Silicone nanocomposite coatings for fabrics

    Science.gov (United States)

    Eberts, Kenneth (Inventor); Lee, Stein S. (Inventor); Singhal, Amit (Inventor); Ou, Runqing (Inventor)

    2011-01-01

    A silicone based coating for fabrics utilizing dual nanocomposite fillers providing enhanced mechanical and thermal properties to the silicone base. The first filler includes nanoclusters of polydimethylsiloxane (PDMS) and a metal oxide and a second filler of exfoliated clay nanoparticles. The coating is particularly suitable for inflatable fabrics used in several space, military, and consumer applications, including airbags, parachutes, rafts, boat sails, and inflatable shelters.

  3. Graphene-Based Polymer Nanocomposites

    Science.gov (United States)

    2015-03-31

    polymerize in-situ around the fillers or even graft to them [71], thus it overcomes the problem of dramatically increased viscosity of the polymer...filler dispersion, increased polymer viscosity during processing and filler damage due to thermal degradation or strong shear forces [3, 82]. At...123, 124]. Figure 1.12 (a) SEM image of the fracture surface of GO/PVA nanocomposite film [85]. (b) TEM image of a clay reinforced Nylon-6

  4. LIGNOCELLULOSE NANOCOMPOSITE CONTAINING COPPER SULFIDE

    Directory of Open Access Journals (Sweden)

    Sanchi Nenkova

    2011-04-01

    Full Text Available Copper sulfide-containing lignocellulose nanocomposites with improved electroconductivity were obtained. Two methods for preparing the copper sulfide lignocellulose nanocomposites were developed. An optimization of the parameters for obtaining of the nanocomposites with respect to obtaining improved electroconductivity, economy, and lower quantities and concentration of copper and sulfur ions in waste waters was conducted. The mechanisms and schemes of delaying and subsequent connection of copper sulfides in the lignocellulosic matrix were investigated. The modification with a system of 2 components: cupric sulfate pentahydrate (CuSO4. 5H2O and sodium thiosulfate pentahydrate (Na2S2O3.5H2O for wood fibers is preferred. Optimal parameters were established for the process: 40 % of the reduction system; hydromodule M=1:6; and ratio of cupric sulfate pentahydrate:sodium thiosulfate pentahydrate = 1:2. The coordinative connection of copper ions with oxygen atoms of cellulose OH groups and aromatic nucleus in lignin macromolecule was observed.

  5. Nanocomposites Based on Biodegradable Polymers

    Directory of Open Access Journals (Sweden)

    Ilaria Armentano

    2018-05-01

    Full Text Available In the present review paper, our main results on nanocomposites based on biodegradable polymers (on a time scale from 2010 to 2018 are reported. We mainly focused our attention on commercial biodegradable polymers, which we mixed with different nanofillers and/or additives with the final aim of developing new materials with tunable specific properties. A wide list of nanofillers have been considered according to their shape, properties, and functionalization routes, and the results have been discussed looking at their roles on the basis of different adopted processing routes (solvent-based or melt-mixing processes. Two main application fields of nanocomposite based on biodegradable polymers have been considered: the specific interaction with stem cells in the regenerative medicine applications or as antimicrobial materials and the active role of selected nanofillers in food packaging applications have been critically revised, with the main aim of providing an overview of the authors’ contribution to the state of the art in the field of biodegradable polymeric nanocomposites.

  6. Nanocrystal-polymer nanocomposite electrochromic device

    Science.gov (United States)

    Milliron, Delia; Runnerstrom, Evan; Helms, Brett; Llordes, Anna; Buonsanti, Raffaella; Garcia, Guillermo

    2015-12-08

    Described is an electrochromic nanocomposite film comprising a solid matrix of an oxide based material, the solid matrix comprising a plurality of transparent conducting oxide (TCO) nanostructures dispersed in the solid matrix and a lithium salt dispersed in the solid matrix. Also described is a near infrared nanostructured electrochromic device having a functional layer comprising the electrochromic nanocomposite film.

  7. High-frequency magnetoimpedance in nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Yurasov, Alexey [Moscow State Institute of Radioengineering, Electronics and Automation (Technical University), Moscow 117454 (Russian Federation)]. E-mail: alexey_yurasov@mail.ru; Granovsky, Alexander [Faculty of Physics, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Tarapov, Sergey [Institute of Radiophysics and Electronics, National Academy of Sciences of Ukraine, Kharkov 61085 (Ukraine); Clerc, Jean-Pierre [Ecole Polytechnique Universitaire de Marseille, Technopole de Chateau-Gombert, Marseille 13453 (France)

    2006-05-15

    The transmission of millimeter-range electromagnetic waves (30-50 GHz) through a magnetic nanocomposite thin film exhibiting tunnel magnetoresistance (TMR) is calculated. The relative change of transmission coefficient in an applied magnetic field due to the magnetorefractive effect is approximately linear with TMR and strongly depends on nanocomposite resistivity and film thickness. The obtained results are in a good agreement with experiment.

  8. High-frequency magnetoimpedance in nanocomposites

    International Nuclear Information System (INIS)

    Yurasov, Alexey; Granovsky, Alexander; Tarapov, Sergey; Clerc, Jean-Pierre

    2006-01-01

    The transmission of millimeter-range electromagnetic waves (30-50 GHz) through a magnetic nanocomposite thin film exhibiting tunnel magnetoresistance (TMR) is calculated. The relative change of transmission coefficient in an applied magnetic field due to the magnetorefractive effect is approximately linear with TMR and strongly depends on nanocomposite resistivity and film thickness. The obtained results are in a good agreement with experiment

  9. Highly Conductive Multifunctional Graphene Polycarbonate Nanocomposites

    Science.gov (United States)

    Yoonessi, Mitra; Gaier, James R.

    2010-01-01

    Graphene nanosheet bisphenol A polycarbonate nanocomposites (0.027 2.2 vol %) prepared by both emulsion mixing and solution blending methods, followed by compression molding at 287 C, exhibited dc electrical percolation threshold of approx.0.14 and approx.0.38 vol %, respectively. The conductivities of 2.2 vol % graphene nanocomposites were 0.512 and 0.226 S/cm for emulsion and solution mixing. The 1.1 and 2.2 vol % graphene nanocomposites exhibited frequency-independent behavior. Inherent conductivity, extremely high aspect ratio, and nanostructure directed assembly of the graphene using PC nanospheres are the main factors for excellent electrical properties of the nanocomposites. Dynamic tensile moduli of nanocomposites increased with increasing graphene in the nanocomposite. The glass transition temperatures were decreased with increasing graphene for the emulsion series. High-resolution electron microscopy (HR-TEM) and small-angle neutron scattering (SANS) showed isolated graphene with no connectivity path for insulating nanocomposites and connected nanoparticles for the conductive nanocomposites. A stacked disk model was used to obtain the average particle radius, average number of graphene layers per stack, and stack spacing by simulation of the experimental SANS data. Morphology studies indicated the presence of well-dispersed graphene and small graphene stacking with infusion of polycarbonate within the stacks.

  10. Biopolymer nanocomposite films reinforced with nanocellulose whiskers

    Science.gov (United States)

    Amit Saxena; Marcus Foston; Mohamad Kassaee; Thomas J. Elder; Arthur J. Ragauskas

    2011-01-01

    A xylan nanocomposite film with improved strength and barrier properties was prepared by a solution casting using nanocellulose whiskers as a reinforcing agent. The 13C cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR) analysis of the spectral data obtained for the NCW/xylan nanocomposite films indicated the signal intensity originating...

  11. Multiwalled Carbon Nanotube-titania Nanocomposites ...

    African Journals Online (AJOL)

    NICOLAAS

    Physical and chemical characterization of the mesoporous nanocomposites from ... On the other hand, nanocomposites from sol-gel synthetic method had larger surface areas, were more defective ... This highlights the great potential of typical nanomaterials in ... various options available, especially for a developing world.

  12. Nanocomposite of graphene and metal oxide materials

    Science.gov (United States)

    Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo

    2012-09-04

    Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10C.

  13. Nanocomposite of graphene and metal oxide materials

    Science.gov (United States)

    Liu, Jun; Aksay, Ilhan A.; Choi, Daiwon; Wang, Donghai; Yang, Zhenguo

    2013-10-15

    Nanocomposite materials comprising a metal oxide bonded to at least one graphene material. The nanocomposite materials exhibit a specific capacity of at least twice that of the metal oxide material without the graphene at a charge/discharge rate greater than about 10 C.

  14. Low-loss Z-type barium hexaferrite composites from nanoscale ZnAl2O4 addition for high-frequency applications

    Science.gov (United States)

    Zheng, Zongliang; Feng, Quanyuan; Harris, Vincent G.

    2018-05-01

    In this study, nanocrystalline ZnAl2O4 (ZA) were introduced to Z-type barium hexaferrite (Co2Z) and the effects of ZA addition upon the crystal-phase composition, microstructure, permeability and permittivity as well as losses characteristics over a wide frequency range of 10 MHz-1 GHz have been systematically investigated. With increasing ZA content (x) from 0 to 15 wt%, the permeability μ' at low frequencies decreased from 12.0 to 4.3, while the permittivity ɛ' was decreased from 27.4 to 10.7. Correspondingly, the frequency stability of permeability and permittivity were improved and the losses were effectively reduced. When x is in the range of 5-10 wt%, the magnetic loss tan δμ is in the order of 10-2 and the dielectric loss tan δɛ is in the order of 10-3 at 300 MHz, which is lower by one order of magnitude compared with that of undoped Co2Z. The modified magnetic and dielectric properties are closely related to the changing phase composition and microstructure.

  15. Parylene nanocomposites using modified magnetic nanoparticles

    International Nuclear Information System (INIS)

    Garcia, Ignacio; Luzuriaga, A. Ruiz de; Grande, H.; Jeandupeux, L.; Charmet, J.; Laux, E.; Keppner, H.; Mecerreyes, D.; Cabanero, German

    2010-01-01

    Parylene/Fe 3 O 4 nanocomposites were synthesized and characterized. The nanocomposites were obtained by chemical vapour deposition polymerization of Parylene onto functionalized Fe 3 O 4 nanoparticles. For this purpose, allyltrichlorosilane was used to modify the surface of 7 nm size Fe 3 O 4 nanoparticles obtained by the coprecipitation method. The magnetic nanoparticles and obtained nanocomposite were characterized with X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA) and magnetic measurements (SQUID). The successful incorporation of different amounts of nanoparticles into Parylene was confirmed by FTIR and TGA. Interestingly, increments in saturation magnetization of the nanocomposites were observed ranging from 0 emu/g of neat Parylene to 16.94 emu/g in the case of nanocomposite films that contained 27.5 wt% of nanoparticles.

  16. Advances in rubber/halloysite nanotubes nanocomposites.

    Science.gov (United States)

    Jia, Zhixin; Guo, Baochun; Jia, Demin

    2014-02-01

    The research advances in rubber/halloysite nanotubes (rubber/HNTs) nanocomposites are reviewed. HNTs are environmentally-friendly natural nanomaterials, which could be used to prepare the rubber-based nanocomposites with high performance and low cost. Unmodified HNTs could be adopted to prepare the rubber/HNTs composites with improved mechanical properties, however, the rubber/HNTs nanocomposites with fine morphology and excellent properties were chiefly prepared with various modifiers by in situ mixing method. A series of rubber/HNTs nanocomposites containing several rubbers (SBR, NR, xSBR, NBR, PU) and different modifiers (ENR, RH, Si69, SA, MAA, ILs) have been investigated. The results showed that all the rubber/HNTs nanocomposites achieved strong interfacial interaction via interfacial covalent bonds, hydrogen bonds or multiple interactions, realized significantly improved dispersion of HNTs at nanoscale and exhibited excellent mechanical performances and other properties.

  17. Fabrication and properties of multiferroic nanocomposite films

    KAUST Repository

    Al-Nassar, Mohammed Y.; Ivanov, Yurii P.; Kosel, Jü rgen

    2015-01-01

    A new type of multiferroic polymer nanocomposite is presented, which exhibits excellent ferromagnetism and ferroelectricity simultaneously at room temperature. The multiferroic nanocomposite consists of a ferroelectric copolymer poly(vinylindene fluoride-trifluoroethylene) [P(VDF-TrFE)] and high aspect ratio ferromagnetic nickel (Ni) nanowires (NWs), which were grown inside anodic aluminum oxide membranes. The fabrication of nanocomposite films with Ni NWs embedded in P(VDF-TrFE) has been successfully carried out via a simple low-temperature spin-coating technique. Structural, ferromagnetic, and ferroelectric properties of the developed nanocomposite have been investigated. The remanent and saturation polarization as well as the coercive field of the ferroelectric phase are slightly affected by the incorporation of the NWs as well as the thickness of the films. While the former two decrease, the last increases by adding the NWs or increasing the thickness. The ferromagnetic properties of the nanocomposite films are found to be isotropic.

  18. Controlled fabrication of luminescent and magnetic nanocomposites

    Science.gov (United States)

    Ma, Yingxin; Zhong, Yucheng; Fan, Jing; Huang, Weiren

    2018-03-01

    Luminescent and magnetic multifunctional nanocomposite is in high demand and widely used in many scales, such as drug delivery, bioseparation, chemical/biosensors, and so on. Although lots of strategies have been successfully developed for the demand of multifunctional nanocomposites, it is not easy to prepare multifunctional nanocomposites by using a simple method, and satisfy all kinds of demands simultaneously. In this work, via a facile and versatile method, luminescent nanocrystals and magnetic nanoparticles were successfully synthesized through self-assembly under vigorous stirring and ultrasonic treatment. These multifunctional nanocomposites are not only water stable but also find wide application such as magnetic separation and concentration with a series of moderate speed, multicolor fluorescence at different emission wavelength, high efficiency of the excitation and emission, and so on. By changing different kinds of luminescent nanocrystals and controlling the amount of luminescent and magnetic nanoparticles, a train of multifunctional nanocomposites was successfully fabricated via a versatile and robust method.

  19. Nanocomposite organomineral hybrid materials. Part 2

    Directory of Open Access Journals (Sweden)

    KUDRYAVTSEV Pavel Gennadievich

    2016-04-01

    Full Text Available The paper addresses the issues of alkoxide method of sol-gel synthesis and non-hydrolytic method of sol-gel synthesis and colloidal method of sol-gel synthesis. The authors also consider an alternative approach based on the use of soluble silicates as precursors in the sol-gel technology, of nanocomposites. It was shown that nanocomposites can be produced through aerogels. The paper also analyzes the mixing technologies of nanocomposites preparation. It has been demonstrated the possibility to change the types of nano-phase which is used for obtaining nanocomposites in different approaches. Various models of packaging spherical, fibrous and layered nanoparticles, introduced into the structure of the nanocomposite, in the preparation thereof were examined.

  20. Nanocomposite organomineral hybrid materials. Part I

    Directory of Open Access Journals (Sweden)

    KUDRYAVTSEV Pavel Gennadievich

    2016-02-01

    Full Text Available The paper addresses the issues of alkoxide method of sol-gel synthesis and non-hydrolytic method of sol-gel synthesis and colloidal method of sol-gel synthesis. The authors also consider an alternative approach based on the use of soluble silicates as precursors in the sol-gel technology, of nanocomposites. It was shown that nanocomposites can be produced through aerogels. The paper also analyzes the mixing technologies of nanocomposites preparation. It has been demonstrated the possibility to change the types of nano-phase which is used for obtaining nanocomposites in different approaches. Various models of packaging spherical, fibrous and layered nanoparticles, introduced into the structure of the nanocomposite, in the preparation thereof were examined.

  1. Nanocomposite organomineral hybrid materials. Part 3

    Directory of Open Access Journals (Sweden)

    KUDRYAVTSEV Pavel Gennadievich

    2016-06-01

    Full Text Available The paper addresses the issues of alkoxide method of sol-gel synthesis and non-hydrolytic method of sol-gel synthesis and colloidal method of sol-gel synthesis. The authors also consider an alternative approach based on the use of soluble silicates as precursors in the sol-gel technology, of nanocomposites. It was shown that nanocomposites can be produced through aerogels. The paper also analyzes the mixing technologies of nanocomposites preparation. It has been demonstrated the possibility to change the types of nano-phase which is used for obtaining nanocomposites in different approaches. Various models of packaging spherical, fibrous and layered nanoparticles, introduced into the structure of the nanocomposite, in the preparation thereof were examined.

  2. Effects of magnetic pre-alignment of nano-powders on formation of high textured barium hexa-ferrite quasi-single crystals via a magnetic forming and liquid participation sintering route

    International Nuclear Information System (INIS)

    Liu, Junliang; Zeng, Yanwei; Zhang, Xingkai; Zhang, Ming

    2015-01-01

    Highly textured barium hexa-ferrite quasi-single crystal with narrow ferromagnetic resonance line-width is believed to be a potential gyromagnetic material for self-biased microwave devices. To fabricate barium hexa-ferrite quasi-single crystal with a high grain orientation degree, a magnetic forming and liquid participation sintering route has been developed. In this paper, the effects of the pre-alignment of the starting nano-powders on the formation of barium quasi-single crystal structures have been investigated. The results indicated that: the crystallites with large sizes and small specific surfaces were easily aligned for they got higher driving forces and lower resistances during magnetic forming. The average restricting magnetic field was about 4.647 kOe to overcome the average friction barrier between crystallites. The pre-aligned crystallites in magnetic forming acted as the “crystal seeds” for oriented growth of the un-aligned crystallites during liquid participation sintering to achieve a high grain orientation. To effectively promote the grain orientation degrees of the sintered pellets, the grain orientation degrees of the green compacts must be higher than a limited value of 15.0%. Barium hexa-ferrite quasi-single crystal with a high grain orientation degree of 98.6% was successfully fabricated after sintering the green compact with its grain orientation degree of 51.1%. - Highlights: • Aligned particles acted as “crystal seeds” for un-aligned ones' oriented growth. • Magnetic field of 4.647 kOe was needed to overcome crystallites' friction barrier. • GOD dramatically increased after sintering if starting GOD exceeded to 15.0%. • Quasi-single crystal was prepared by sintering green compact with GOD of 51.1%

  3. Effects of magnetic pre-alignment of nano-powders on formation of high textured barium hexa-ferrite quasi-single crystals via a magnetic forming and liquid participation sintering route

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Junliang, E-mail: liujunliang@yzu.edu.cn [Key Laboratory of Environmental Materials and Engineering of Jiangsu Province, School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Zeng, Yanwei [State Key Laboratory of Materials-Oriented Chemical Engineering, School of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 (China); Zhang, Xingkai [Key Laboratory of Environmental Materials and Engineering of Jiangsu Province, School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Zhang, Ming [Key Laboratory of Environmental Materials and Engineering of Jiangsu Province, School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002 (China); Testing Center of Yangzhou University, Yangzhou 225002 (China)

    2015-05-15

    Highly textured barium hexa-ferrite quasi-single crystal with narrow ferromagnetic resonance line-width is believed to be a potential gyromagnetic material for self-biased microwave devices. To fabricate barium hexa-ferrite quasi-single crystal with a high grain orientation degree, a magnetic forming and liquid participation sintering route has been developed. In this paper, the effects of the pre-alignment of the starting nano-powders on the formation of barium quasi-single crystal structures have been investigated. The results indicated that: the crystallites with large sizes and small specific surfaces were easily aligned for they got higher driving forces and lower resistances during magnetic forming. The average restricting magnetic field was about 4.647 kOe to overcome the average friction barrier between crystallites. The pre-aligned crystallites in magnetic forming acted as the “crystal seeds” for oriented growth of the un-aligned crystallites during liquid participation sintering to achieve a high grain orientation. To effectively promote the grain orientation degrees of the sintered pellets, the grain orientation degrees of the green compacts must be higher than a limited value of 15.0%. Barium hexa-ferrite quasi-single crystal with a high grain orientation degree of 98.6% was successfully fabricated after sintering the green compact with its grain orientation degree of 51.1%. - Highlights: • Aligned particles acted as “crystal seeds” for un-aligned ones' oriented growth. • Magnetic field of 4.647 kOe was needed to overcome crystallites' friction barrier. • GOD dramatically increased after sintering if starting GOD exceeded to 15.0%. • Quasi-single crystal was prepared by sintering green compact with GOD of 51.1%.

  4. Effective Optical Properties of Plasmonic Nanocomposites

    Directory of Open Access Journals (Sweden)

    Christoph Etrich

    2014-01-01

    Full Text Available Plasmonic nanocomposites find many applications, such as nanometric coatings in emerging fields, such as optotronics, photovoltaics or integrated optics. To make use of their ability to affect light propagation in an unprecedented manner, plasmonic nanocomposites should consist of densely packed metallic nanoparticles. This causes a major challenge for their theoretical description, since the reliable assignment of effective optical properties with established effective medium theories is no longer possible. Established theories, e.g., the Maxwell-Garnett formalism, are only applicable for strongly diluted nanocomposites. This effective description, however, is a prerequisite to consider plasmonic nanocomposites in the design of optical devices. Here, we mitigate this problem and use full wave optical simulations to assign effective properties to plasmonic nanocomposites with filling fractions close to the percolation threshold. We show that these effective properties can be used to properly predict the optical action of functional devices that contain nanocomposites in their design. With this contribution we pave the way to consider plasmonic nanocomposites comparably to ordinary materials in the design of optical elements.

  5. Biomimetic magnetic nanocomposite for smart skins

    KAUST Repository

    Alfadhel, Ahmed; Kosel, Jü rgen

    2015-01-01

    We report a biomimetic tactile sensor consisting of magnetic nanocomposite artificial cilia and magnetic sensors. The nanocomposite is fashioned from polydimethylsiloxane and iron nanowires and exhibits a permanent magnetic behavior. This enables remote operation without an additional magnetic field to magnetize the nanowires, which simplifies device integration. Moreover, the highly elastic and easy patternable nanocomposite is corrosion resistant and thermally stable. The highly sensitive and power efficient tactile sensors can detect vertical and shear forces from interactions with objects. The sensors can operate in dry and wet environment with the ability to measure different properties such as the texture and the movement or stability of objects, with easily adjustable performance.

  6. Polymer/metal nanocomposites for biomedical applications.

    Science.gov (United States)

    Zare, Yasser; Shabani, Iman

    2016-03-01

    Polymer/metal nanocomposites consisting of polymer as matrix and metal nanoparticles as nanofiller commonly show several attractive advantages such as electrical, mechanical and optical characteristics. Accordingly, many scientific and industrial communities have focused on polymer/metal nanocomposites in order to develop some new products or substitute the available materials. In the current paper, characteristics and applications of polymer/metal nanocomposites for biomedical applications are extensively explained in several categories including strong and stable materials, conductive devices, sensors and biomedical products. Moreover, some perspective utilizations are suggested for future studies. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Biomimetic magnetic nanocomposite for smart skins

    KAUST Repository

    Alfadhel, Ahmed

    2015-11-01

    We report a biomimetic tactile sensor consisting of magnetic nanocomposite artificial cilia and magnetic sensors. The nanocomposite is fashioned from polydimethylsiloxane and iron nanowires and exhibits a permanent magnetic behavior. This enables remote operation without an additional magnetic field to magnetize the nanowires, which simplifies device integration. Moreover, the highly elastic and easy patternable nanocomposite is corrosion resistant and thermally stable. The highly sensitive and power efficient tactile sensors can detect vertical and shear forces from interactions with objects. The sensors can operate in dry and wet environment with the ability to measure different properties such as the texture and the movement or stability of objects, with easily adjustable performance.

  8. Single and double-layer composite microwave absorbers with hexaferrite BaZn{sub 0.6}Zr{sub 0.3}X{sub 0.3}Fe{sub 10.8}O{sub 19} (X = Ti, Ce, Sn) powders

    Energy Technology Data Exchange (ETDEWEB)

    Afghahi, Seyyed Salman Seyyed [Department of Materials Science and Engineering, Imam Hossein University, Tehran (Iran, Islamic Republic of); Jafarian, Mojtaba, E-mail: m.jafarian@srbiau.ac.ir [Young Researchers and Elites Club, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Atassi, Yomen [Department of Applied Physics, Higher Institute for Applied Sciences and Technology, Damascus (Syrian Arab Republic); Stergiou, Charalampos A. [Lab. of Inorganic Materials, Centre for Research and Technology Hellas, 57001, Thermi (Greece)

    2017-01-15

    In the present study, substituted barium hexaferrites with the composition BaZn{sub 0.6}Zr{sub 0.3} × {sub 0.3}Fe{sub 10.8}O{sub 19} (where X = Ti, Ce, Sn) are prepared with the solid-state reaction method. X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and network analysis techniques are used to analyze the crystal phases, morphology, static magnetic and microwave absorption properties, respectively. Based on the recorded results, barium hexaferrite is the major phase obtained after milling of the powders for 20 h, followed by calcination at 1000 °C for 5 h. The morphology of the particles of the substituted ferrite samples is plate-like with hexagonal shape. The microwave absorption in the X-band of epoxy composites loaded with the ferrite fillers, either separately, in pairs or all together, has been extensively investigated. Multicomponent composites filled with the new hexaferrites under study are promising candidates for electromagnetic absorbers in the 8–12 GHz range. It is found that single-layer absorbers of 5 mm thickness with 45 wt% of a binary (Sn and Ti-doped hexaferrite) or ternary filler mixture exhibit the maximum bandwidth of 2.7 GHz at the level of −10 dB or maximum losses of 26.4 dB at 10.8 GHz, respectively. - Highlights: • Preparation of substituted hexaferrites via mechanical activation. • We designed a broad band microwave absorber with mixing powders. • We designed single layer absorber with RL{sub min} = −26.4 dB and 1.6 GHz bandwidth. • We designed double layer absorbers, as monoband absorbers at a matching frequency.

  9. An investigation on the microstructures and magnetic properties of the Sr0.35−xBaxCa0.30La0.35Fe11.71Co0.29O19 hexaferrites

    International Nuclear Information System (INIS)

    Yang, Yujie; Liu, Xiansong

    2014-01-01

    M-type hexaferrite Sr 0.35−x Ba x Ca 0.30 La 0.35 Fe 11.71 Co 0.29 O 19 (0≤x≤0.35) magnetic powders and magnets were prepared by the solid-state reaction. The phase compositions of the magnetic powders were investigated by X-ray diffraction. X-ray diffraction patterns show that the hexagonal single phase is obtained in all samples. The micrographs of the magnets were observed by a field emission scanning electron microscopy. All magnets have formed hexagonal structures and the particles are distributed evenly. Magnetic properties of the magnets were measured by a magnetic properties test instrument. The remanence, intrinsic coercivity, magnetic induction coercivity and maximum energy product of the magnets continuously decrease with increasing barium content (x). - Highlights: • Hexaferrites Sr 0.35−x Ba x Ca 0.30 La 0.35 Fe 11.71 Co 0.29 O 19 were prepared by the solid-state reaction. • The hexagonal single phase is obtained in all magnetic powders. • B r , H cj , H cb and (BH) max of the magnets continuously decrease with increasing barium content

  10. Synthesis and characterization of the Y-type barium hexaferrite (Ba_2CoZnFe_1_2O_2_2) obtained by ultrasonic interdispersion of chemical precitates

    International Nuclear Information System (INIS)

    Junior, E.S.G.; Santos, M.R.C.; Jardim, P.M.; Ogasawara, T.; Almeida, L.H.

    2011-01-01

    This work is to study the synthesis and characterization of the Y-type barium hexaferrite powder (Ba2CoZnFe12O22) by chemical precipitation of the precursor materials Fe(OH)3, Co(OH)2, Zn(OH)2 and Ba(OH)2 separately and ultrasonic inter-dispersion, followed by drying and calcining. The study shows that the phase formation of the Y-type barium hexaferrite begins to emerge already at a temperature of 900 ° C with further phases still present, characterized by X-ray diffraction, the grain growth of the final product of the synthesis as a function of calcination temperature is visible by SEM, the measured magnetic of the powder through the hysteresis curve confirms that the material is magnetically soft at room temperature. The synthesis method developed in this research is an option to achieve the results that would be obtained if the co-precipitation of the ferric hydroxides, of cobalt, zinc and barium were thermodynamically possible. (author)

  11. Room-temperature multiferroic and magnetocapacitance effects in M-type hexaferrite BaFe{sub 10.2}Sc{sub 1.8}O{sub 19}

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Rujun, E-mail: tangrj@suda.edu.cn, E-mail: yanghao@nuaa.edu.cn; Zhou, Hao; You, Wenlong [Jiangsu Key Laboratory of Thin Films, College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006 (China); Yang, Hao, E-mail: tangrj@suda.edu.cn, E-mail: yanghao@nuaa.edu.cn [College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 211106 (China)

    2016-08-22

    The room-temperature multiferroic and magnetocapacitance (MC) effects of polycrystalline M-type hexaferrite BaFe{sub 10.2}Sc{sub 1.8}O{sub 19} have been investigated. The results show that the magnetic moments of insulating BaFe{sub 10.2}Sc{sub 1.8}O{sub 19} can be manipulated by the electric field at room temperature, indicating the existence of magnetoelectric coupling. Moreover, large MC effects are also observed around the room temperature. A frequency dependence analysis shows that the Maxwell-Wagner type magnetoresistance effect is the dominant mechanism for MC effects at low frequencies. Both the magnetoelectric-type and non-magnetoelectric-type spin-phonon couplings contribute to the MC effects at high frequencies with the former being the dominant mechanism. The above results show that the hexaferrite BaFe{sub 10.2}Sc{sub 1.8}O{sub 19} is a room-temperature multiferroic material that can be potentially used in magnetoelectric devices.

  12. Morphological and magnetic properties of sol-gel synthetized meso and macroporous spheres of barium hexaferrite (BaFe{sub 12}O{sub 19})

    Energy Technology Data Exchange (ETDEWEB)

    Torres-Cadenas, S., E-mail: storres_c@hotmail.com [Instituto de Investigaciones Metalúrgicas y Materiales, UMSNH, Edificio U, Ciudad Universitaria, Santiago Tapia 403, Colonia Centro, 58030 Morelia (Mexico); Reyes-Gasga, José, E-mail: jreyes@fisica.unam.mx [Instituto de Física, UNAM, Circuito de la Investigación s/n, Ciudad Universitaria, 04510 Coyoacán, México, D.F. (Mexico); Bravo-Patiño, A., E-mail: brapal@hotmail.com [Centro Multidisciplinario de Estudios en Biotecnología (CMEB) de la FMVZ, UMSNH, Posta Zootécnica, km. 8.5 carretera Morelia-Zinapecuaro, C.P. 58890 col. La Palma, Tarimbaro, Michoacán (Mexico); Betancourt, I., E-mail: israelb@iim.unam.mx [Instituto de Investigaciones en Materiales, UNAM, Ciudad de México C.P. 04510 (Mexico); Contreras-García, M.E., E-mail: eucontre@gmail.com [Instituto de Investigaciones Metalúrgicas y Materiales, UMSNH, Edificio U, Ciudad Universitaria, Santiago Tapia 403, Colonia Centro, 58030 Morelia (Mexico)

    2017-06-15

    Highlights: • 1.5 µm porous spheres of BaFe{sub 12}O{sub 19} were synthetized by the sol-gel method. • Surfactant Tween20 (C{sub 58}H{sub 114}O{sub 26}) enabled the creation of the mesoporous structure. • Polystyrene spheres (PS) were used as the template for the formation of macropores. • Spheres resembled a nest or ball-of-yarn type of elongated BaFe{sub 12}O{sub 19} crystals. • Magnetic properties are evaluated as function of the calcination temperature. - Abstract: Porous spherical aggregates of barium hexaferrite (BaFe{sub 12}O{sub 19}) with 1.5 µm in diameter were synthetized by the surfactant-assisted sol-gel method. The surfactant Tween20 (C{sub 58}H{sub 114}O{sub 26}), which enables mesoporous structures, as well as polystyrene spheres (PS), as the template agent for the formation of macropores, were used. Two synthetic routes (hereafter named A and B), whose difference was the absence or presence of PS, were followed for synthesis. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in high resolution mode (HRTEM) were used for characterization. Size and morphology of the spheres were similar in both cases and they resemble a nest or ball-of-yarn type structure. Pore size and BaFe{sub 12}O{sub 19} crystal size produced by the two routes are different. The magnetic properties of the spheres were evaluated using a vibrating sample magnetometer (VSM) as function of the calcination temperature. The spheres present ferromagnetic behavior in both routes.

  13. Morphological and magnetic properties of sol-gel synthetized meso and macroporous spheres of barium hexaferrite (BaFe12O19)

    International Nuclear Information System (INIS)

    Torres-Cadenas, S.; Reyes-Gasga, José; Bravo-Patiño, A.; Betancourt, I.; Contreras-García, M.E.

    2017-01-01

    Highlights: • 1.5 µm porous spheres of BaFe 12 O 19 were synthetized by the sol-gel method. • Surfactant Tween20 (C 58 H 114 O 26 ) enabled the creation of the mesoporous structure. • Polystyrene spheres (PS) were used as the template for the formation of macropores. • Spheres resembled a nest or ball-of-yarn type of elongated BaFe 12 O 19 crystals. • Magnetic properties are evaluated as function of the calcination temperature. - Abstract: Porous spherical aggregates of barium hexaferrite (BaFe 12 O 19 ) with 1.5 µm in diameter were synthetized by the surfactant-assisted sol-gel method. The surfactant Tween20 (C 58 H 114 O 26 ), which enables mesoporous structures, as well as polystyrene spheres (PS), as the template agent for the formation of macropores, were used. Two synthetic routes (hereafter named A and B), whose difference was the absence or presence of PS, were followed for synthesis. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) in high resolution mode (HRTEM) were used for characterization. Size and morphology of the spheres were similar in both cases and they resemble a nest or ball-of-yarn type structure. Pore size and BaFe 12 O 19 crystal size produced by the two routes are different. The magnetic properties of the spheres were evaluated using a vibrating sample magnetometer (VSM) as function of the calcination temperature. The spheres present ferromagnetic behavior in both routes.

  14. Effect of Mg{sup 2+} and Ti{sup 4+} dopants on the structural, magnetic and high-frequency ferromagnetic properties of barium hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Shams, Mohammad H. [Department of Physics, University of Isfahan, Hezar Jarib Street, Isfahan 81746-73441 (Iran, Islamic Republic of); Rozatian, Amir S.H., E-mail: a.s.h.rozatian@phys.ui.ac.ir [Department of Physics, University of Isfahan, Hezar Jarib Street, Isfahan 81746-73441 (Iran, Islamic Republic of); Yousefi, Mohammad H. [Department of Physics, University of Isfahan, Hezar Jarib Street, Isfahan 81746-73441 (Iran, Islamic Republic of); Valíček, Jan [Institute of Physics, Faculty of Mining and Geology, VŠB – Technical University of Ostrava, 17. Listopadu 15, 70833 Ostrava-Poruba (Czech Republic); Šepelák, Vladimir [Institute of Nanotechnology, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen (Germany); Slovak Academy of Sciences, Watsonova 45, 04001 Košice (Slovakia)

    2016-02-01

    The doped barium hexaferrite, BaFe{sub 12−x}(Mg{sub 0.5}Ti{sub 0.5}){sub x}O{sub 19} with 1≤x≤5, is synthesized by a solid state ceramic method. Its crystalline structure, morphology, as well as static and dynamic magnetic properties are investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), vibrating sample magnetometry, and vector network analysis, respectively. The cation distribution of Mg{sup 2+} and Ti{sup 4+} in the hexagonal structure of BaFe{sub 12−x}(Mg{sub 0.5}Ti{sub 0.5}){sub x}O{sub 19} is investigated by {sup 57}Fe Mössbauer spectroscopy. The effect of Mg{sup 2+} and Ti{sup 4+} dopants on static and high-frequency magnetic properties of the ferrite is studied. - Highlights: • The BaFe{sub 12−x}(MgTi){sub 0.5x}O{sub 19} (x =1– 5) are synthesized by a solid state reaction method. • The Mg{sup 2+} and Ti{sup 4+} dopants take positions 12k for x=1 and 4f{sub 1} and 4f{sub 2} for x=5. • The coercivity and magnetization are decreased with an increase in Mg–Ti content. • The ferromagnetic resonance frequency is decreased with increase of x. • The FMR is shifted to lower frequencies due to the reduction of the anisotropy field.

  15. Large-Strain Transparent Magnetoactive Polymer Nanocomposites

    Science.gov (United States)

    Meador, Michael A.

    2012-01-01

    A document discusses polymer nano - composite superparamagnetic actuators that were prepared by the addition of organically modified superparamagnetic nanoparticles to the polymer matrix. The nanocomposite films exhibited large deformations under a magnetostatic field with a low loading level of 0.1 wt% in a thermoplastic polyurethane elastomer (TPU) matrix. The maximum actuation deformation of the nanocomposite films increased exponentially with increasing nanoparticle concentration. The cyclic deformation actuation of a high-loading magnetic nanocomposite film was examined in a low magnetic field, and it exhibited excellent reproducibility and controllability. Low-loading TPU nanocomposite films (0.1-2 wt%) were transparent to semitransparent in the visible wavelength range, owing to good dispersion of the magnetic nanoparticles. Magnetoactuation phenomena were also demonstrated in a high-modulus, high-temperature polyimide resin with less mechanical deformation.

  16. Polymer Nanocomposite Membranes for Antifouling Nanofiltration.

    Science.gov (United States)

    Kamal, Tahseen; Ali, Nauman; Naseem, Abbas A; Khan, Sher B; Asiri, Abdullah M

    2016-01-01

    Fouling refers to the unwanted and undesirable attachment of biological macromolecules, inorganic, organic matter, and microorganisms on water contact surfaces. Fouling reduces the performance of devices involving these submerged surfaces and is considered the bottle-neck issue for various applications in the biomedical industry, food processing, and water treatment, especially in reverse osmosis (RO) desalination. Investigations have proven that nanocomposite membranes can exhibit enhanced antifouling performances and can be used for longer life times. The nanocomposite means addition of nanomaterials to main matrix at low loadings, exhibiting better properties compared to virgin matrix. In this review, a summarized description about related methods and their mechanisms for the fabrication of nanocomposite membranes with antifouling properties has been documented. Around 87 manuscripts including 10 patents were used to demonstrate the antifouling applications of of various nanocomposite membranes.

  17. Polymer nanotube nanocomposites: synthesis, properties, and applications

    National Research Council Canada - National Science Library

    Mittal, Vikas

    2010-01-01

    ... in these commercially important areas of polymer technology. It sums up recent advances in nanotube composite synthesis technology, provides basic introduction to polymer nanotubes nanocomposite technology for the readers new to this field, provides valuable...

  18. In situ SU-8 silver nanocomposites

    DEFF Research Database (Denmark)

    Fischer, Søren Vang; Uthuppu, Basil; Jakobsen, Mogens Havsteen

    2015-01-01

    Nanocomposite materials containing metal nanoparticles are of considerable interest in photonics and optoelectronics applications. However, device fabrication of such materials always encounters the challenge of incorporation of preformed nanoparticles into photoresist materials. As a solution to...

  19. Cellulose nanocrystals reinforced foamed nitrile rubber nanocomposites.

    Science.gov (United States)

    Chen, Yukun; Zhang, Yuanbing; Xu, Chuanhui; Cao, Xiaodong

    2015-10-05

    Research on foamed nitrile rubber (NBR)/cellulose nanocrystals (CNs) nanocomposites is rarely found in the literatures. In this paper, CNs suspension and NBR latex was mixed to prepared the foamed NBR/CNs nanocomposites. We found that the CNs mainly located in the cell walls, effectively reinforcing the foamed NBR. The strong interaction between the CNs and NBR matrix restricted the mobility of NBR chains surrounding the CNs, hence increasing the crosslink density of the NBR matrix. CNs exhibited excellent reinforcement on the foamed NBR: a remarkable increase nearly 76% in the tensile strength of the foamed nanocomposites was achieved with a load of only 15 phr CNs. Enhanced mechanical properties make the foamed NBR/CNs nanocomposites a promising damping material for industrial applications with a potential to reduce the petroleum consumption. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Dielectric properties of nanosilica filled epoxy nanocomposites

    Indian Academy of Sciences (India)

    M G Veena

    Polymer nanocomposites are the 21st century engineering materials with wide range of ... the electronic industry for dielectric materials in electrical insulation ..... be ascribed to the interface barriers and chain entangle- ments towards the ...

  1. Fatigue-free PZT-based nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, H J; Sando, M [Nat. Ind. Res. Inst., Nagoya (Japan); Tajima, K [Synergy Ceramics Lab., Fine Ceramics Research Association, Nagoya (Japan); Niihara, K [ISIR, Osaka Univ., Mihogaoka, Ibaraki (Japan)

    1999-03-01

    The goal of this study is to fabricate fatigue-free piezoelectrics-based nanocomposites. Lead zirconate titanate (PZT) and metallic platinum (Pt) were selected as a matrix and secondary phase dispersoid. Fine Pt particles were homogeneously dispersed in the PZT matrix. Fatigue properties of the unpoled PZT-based nanocomposite under electrical cyclic loading were investigated. The electrical-field-induced crack growth was monitored by an optical microscope, and it depended on the number of cycles the sample was subjected to. Resistance to fatigue was significantly enhanced in the nanocomposite. The excellent fatigue behavior of the PZT/Pt nanocomposites may result from the grain boundary strenghtening due to the interaction between the matrix and Pt particles. (orig.) 8 refs.

  2. Polymer and ceramic nanocomposites for aerospace applications

    Science.gov (United States)

    Rathod, Vivek T.; Kumar, Jayanth S.; Jain, Anjana

    2017-11-01

    This paper reviews the potential of polymer and ceramic matrix composites for aerospace/space vehicle applications. Special, unique and multifunctional properties arising due to the dispersion of nanoparticles in ceramic and metal matrix are briefly discussed followed by a classification of resulting aerospace applications. The paper presents polymer matrix composites comprising majority of aerospace applications in structures, coating, tribology, structural health monitoring, electromagnetic shielding and shape memory applications. The capabilities of the ceramic matrix nanocomposites to providing the electromagnetic shielding for aircrafts and better tribological properties to suit space environments are discussed. Structural health monitoring capability of ceramic matrix nanocomposite is also discussed. The properties of resulting nanocomposite material with its disadvantages like cost and processing difficulties are discussed. The paper concludes after the discussion of the possible future perspectives and challenges in implementation and further development of polymer and ceramic nanocomposite materials.

  3. Graphene oxide nanocomposites and their electrorheology

    International Nuclear Information System (INIS)

    Zhang, Wen Ling; Liu, Ying Dan; Choi, Hyoung Jin

    2013-01-01

    Graphical abstract: - Highlights: • GO-based PANI, NCOPA and PS nanocomposites are prepared. • The nanocomposites are adopted as novel electrorheological (ER) candidates. • Their critical ER characteristics and dielectric performance are analyzed. • Typical ER behavior widens applications of GO-based nanocomposites. - Abstract: Graphene oxide (GO), a novel one-atom carbon system, has become one of the most interesting materials recently due to its unique physical and chemical properties in addition to graphene. This article briefly reviews a recent progress of the fabrication of GO-based polyaniline, ionic N-substituted copolyaniline and polystyrene nanocomposites. The critical electrorheological characteristics such as flow response and yield stress from rheological measurement, relaxation time and achievable polarizability from dielectric analysis are also analyzed

  4. Multiwalled Carbon Nanotube-titania Nanocomposites ...

    African Journals Online (AJOL)

    Physical and chemical characterization of the mesoporous nanocomposites from the two synthetic methods were investigated using Raman spectroscopy, thermogravimetric analysis, Fourier transformation infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, high-resolution transmission ...

  5. Titanium Nanocomposite: Lightweight Multifunction Structural Material

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to research and develop lightweight metal matrix nanocomposites (MMnC) using a Titanium (Ti) metal matrix. Ti MMnC will crosscut the advancement of both...

  6. Electrical conduction of a XLPE nanocomposite

    Science.gov (United States)

    Park, Yong-Jun; Sim, Jae-Yong; Lim, Kee-Joe; Nam, Jin-Ho; Park, Wan-Gi

    2014-07-01

    The resistivity, breakdown strength, and formation of space charges are very important factors for insulation design of HVDC cable. It is known that a nano-sized metal-oxide inorganic filler reduces the formation of space charges in the polymer nanocomposite. Electrical conduction of cross-linked polyethylene(XLPE) nanocomposite insulating material is investigated in this paper. The conduction currents of two kinds of XLPE nanocomposites and XLPE without nano-filler were measured at temperature of 303 ~ 363 K under the applied electric fields of 10 ~ 50 kV/mm. The current of the nanocomposite specimen is smaller than that of XLPE specimen without nano-filler. The conduction mechanism may be explained in terms of Schottky emission and multi-core model.

  7. Polymer nanocomposites: polymer and particle dynamics

    KAUST Repository

    Kim, Daniel; Srivastava, Samanvaya; Narayanan, Suresh; Archer, Lynden A.

    2012-01-01

    Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has

  8. Polymer matrix nanocomposites for automotive structural components

    Science.gov (United States)

    Naskar, Amit K.; Keum, Jong K.; Boeman, Raymond G.

    2016-12-01

    Over the past several decades, the automotive industry has expended significant effort to develop lightweight parts from new easy-to-process polymeric nanocomposites. These materials have been particularly attractive because they can increase fuel efficiency and reduce greenhouse gas emissions. However, attempts to reinforce soft matrices by nanoscale reinforcing agents at commercially deployable scales have been only sporadically successful to date. This situation is due primarily to the lack of fundamental understanding of how multiscale interfacial interactions and the resultant structures affect the properties of polymer nanocomposites. In this Perspective, we critically evaluate the state of the art in the field and propose a possible path that may help to overcome these barriers. Only once we achieve a deeper understanding of the structure-properties relationship of polymer matrix nanocomposites will we be able to develop novel structural nanocomposites with enhanced mechanical properties for automotive applications.

  9. Polymer nanotube nanocomposites: synthesis, properties, and applications

    National Research Council Canada - National Science Library

    Mittal, Vikas

    2010-01-01

    ... insights for the use of technologies for polymer nanocomposites for commercial application, and features chapters from the most experienced researches in the field"-- "The purpose of this edited book...

  10. Conducting polymer nanocomposite-based supercapacitors

    OpenAIRE

    Liew, Soon Yee; Walsh, Darren A.; Chen, George Z.

    2016-01-01

    The use of nanocomposites of electronically-conducting polymers for supercapacitors has increased significantly over the past years, due to their high capacitances and abilities to withstand many charge-discharge cycles. We have recently been investigating the use of nanocomposites of electronically-conducting polymers containing conducting and non-conducting nanomaterials such as carbon nanotubes and cellulose nanocrystals, for use in supercapacitors. In this contribution, we provide a summa...

  11. Synthesis of polyanthranilic acid–Au nanocomposites by emulsion ...

    Indian Academy of Sciences (India)

    Administrator

    PANA–Au nanocomposites are characterized by SEM, equipped with EDS, TGA, FT–IR, XRD and electrochemical techniques. XRD of ... Polyanthranilic acid; nanocomposite; in situ polymerization; emulsion polymerization; nano- particles. 1.

  12. Handbook of polymer nanocomposites processing, performance and application

    CERN Document Server

    Mohanty, Amar; Misra, Manjusri; Kar, Kamal K; Pandey, Jitendra; Rana, Sravendra; Takagi, Hitoshi; Nakagaito, Antonio; Kim, Hyun-Joong

    Volume A forms one volume of a Handbook about Polymer Nanocomposites. In some 20 chapters the preparation, architecture, characterisation, properties and application of polymer nanocomposites are discussed by experts in their respective fields.

  13. Characterization of PAN/ATO nanocomposites prepared by solution ...

    Indian Academy of Sciences (India)

    Wintec

    Institute of Materials and Chemical Engineering, Zhongyuan University of Technology, ... The storage modulus of the nanocomposites increased with increasing content of ATO, ... Thermal stability of the nanocomposites was found remarka-.

  14. Plasma deposition of nanocomposite thin films : process concept and realisation

    NARCIS (Netherlands)

    Alcott, G.R.

    2004-01-01

    Recent developments in materials technology, fuelled by the growing hype surrounding nanotechnology, have given rise to a new breed of materials known as nanocomposites. Nanocomposite materials (a subgroup of hybrid materials) are formed from standard polymers impregnated with nanometre sized

  15. Unique morphology of dispersed clay particles in a polymer nanocomposite

    CSIR Research Space (South Africa)

    Malwela, T

    2011-02-01

    Full Text Available This communication reports a unique morphology of dispersed clay particles in a polymer nanocomposite. A nanocomposite of poly[butylene succinate)-co-adipate] (PBSA) with 3 wt% of organically modified montmorillonite was prepared by melt...

  16. Rapid microwave processing of epoxy nanocomposites using carbon nanotubes

    OpenAIRE

    Luhyna, Nataliia; Inam, Fawad; Winnington, Ian

    2013-01-01

    Microwave processing is one of the rapid processing techniques for manufacturing nanocomposites. There is very little work focussing on the addition of CNTs for shortening the curing time of epoxy nanocomposites. Using microwave energy, the effect of CNT addition on the curing of epoxy nanocomposites was researched in this work. Differential scanning calorimetry (DSC) was used to determine the degree of cure for epoxy and nanocomposite samples. CNT addition significantly reduced the duration ...

  17. Nanocomposites: The End of Compromise

    Science.gov (United States)

    van Damme, H.

    Increase the Young's modulus of a glassy resin by a factor of ten without making it heavier, for a new ski design, for example? Triple the rupture strength of an elastomer? Improve the thermal behaviour of an object made from a thermoplastic polymer by 100 degrees, to make a car dashboard, for example, or a part for the engine? Double the fire resistance time for the sheath around an electricity cable? Reduce the oxygen permeability of a film by a factor of ten, to make long conservation food packaging? All these things have been made possible by incorporating a few percent of inorganic nanoparticles in a polymer matrix. Figures 14.1 and 14.2 illustrate two such nanocomposites: the first was obtained by incorporating lamellar clay particles, and the second by incorporating fibrous nanoparticles, in fact, carbon nanotubes.

  18. Graphite nanoreinforcements in polymer nanocomposites

    Science.gov (United States)

    Fukushima, Hiroyuki

    Nanocomposites composed of polymer matrices with clay reinforcements of less than 100 nm in size, are being considered for applications such as interior and exterior accessories for automobiles, structural components for portable electronic devices, and films for food packaging. While most nanocomposite research has focused on exfoliated clay platelets, the same nanoreinforcement concept can be applied to another layered material, graphite, to produce nanoplatelets and nanocomposites. Graphite is the stiffest material found in nature (Young's Modulus = 1060 GPa), having a modulus several times that of clay, but also with excellent electrical and thermal conductivity. The key to utilizing graphite as a platelet nanoreinforcement is in the ability to exfoliate this material. Also, if the appropriate surface treatment can be found for graphite, its exfoliation and dispersion in a polymer matrix will result in a composite with not only excellent mechanical properties but electrical properties as well, opening up many new structural applications as well as non-structural ones where electromagnetic shielding and high thermal conductivity are requirements. In this research, a new process to fabricate exfoliated nano-scale graphite platelets was established (Patent pending). The size of the resulted graphite platelets was less than 1 um in diameter and 10 nm in thickness, and the surface area of the material was around 100 m2/g. The reduction of size showed positive effect on mechanical properties of composites because of the increased edge area and more functional groups attached with it. Also various surface treatment techniques were applied to the graphite nanoplatelets to improve the surface condition. As a result, acrylamide grafting treatment was found to enhance the dispersion and adhesion of graphite flakes in epoxy matrices. The resulted composites showed better mechanical properties than those with commercially available carbon fibers, vapor grown carbon fibers

  19. High performance polyethylene nanocomposite fibers

    Directory of Open Access Journals (Sweden)

    A. Dorigato

    2012-12-01

    Full Text Available A high density polyethylene (HDPE matrix was melt compounded with 2 vol% of dimethyldichlorosilane treated fumed silica nanoparticles. Nanocomposite fibers were prepared by melt spinning through a co-rotating twin screw extruder and drawing at 125°C in air. Thermo-mechanical and morphological properties of the resulting fibers were then investigated. The introduction of nanosilica improved the drawability of the fibers, allowing the achievement of higher draw ratios with respect to the neat matrix. The elastic modulus and creep stability of the fibers were remarkably improved upon nanofiller addition, with a retention of the pristine tensile properties at break. Transmission electronic microscope (TEM images evidenced that the original morphology of the silica aggregates was disrupted by the applied drawing.

  20. Shape-morphing nanocomposite origami.

    Science.gov (United States)

    Andres, Christine M; Zhu, Jian; Shyu, Terry; Flynn, Connor; Kotov, Nicholas A

    2014-05-20

    Nature provides a vast array of solid materials that repeatedly and reversibly transform in shape in response to environmental variations. This property is essential, for example, for new energy-saving technologies, efficient collection of solar radiation, and thermal management. Here we report a similar shape-morphing mechanism using differential swelling of hydrophilic polyelectrolyte multilayer inkjets deposited on an LBL carbon nanotube (CNT) composite. The out-of-plane deflection can be precisely controlled, as predicted by theoretical analysis. We also demonstrate a controlled and stimuli-responsive twisting motion on a spiral-shaped LBL nanocomposite. By mimicking the motions achieved in nature, this method offers new opportunities for the design and fabrication of functional stimuli-responsive shape-morphing nanoscale and microscale structures for a variety of applications.

  1. Characterization of Hybrid Epoxy Nanocomposites

    Science.gov (United States)

    Simcha, Shelly; Dotan, Ana; Kenig, Samuel; Dodiuk, Hanna

    2012-01-01

    This study focused on the effect of Multi Wall Carbon Nanotubes (MWCNT) content and its surface treatment on thermo-mechanical properties of epoxy nanocomposites. MWCNTs were surface treated and incorporated into two epoxy systems. MWCNT's surface treatments were based on: (a) Titania coating obtained by sol-gel process and (b) a nonionic surfactant. Thermo-mechanical properties improvement was obtained following incorporation of treated MWCNT. It was noticed that small amounts of titania coated MWCNT (0.05 wt %) led to an increase in the glass transition temperature and stiffness. The best performance was achieved adding 0.3 wt % titania coated MWCNT where an increase of 10 °C in the glass transition temperature and 30% in storage modulus were obtained. PMID:28348313

  2. Nanotechnology : emerging applications of cellulose-based green magnetic nanocomposites

    Science.gov (United States)

    Tao Wang; Zhiyong Cai; Lei Liu; Ilker S. Bayer; Abhijit Biswas

    2010-01-01

    In recent years, a new type of nanocomposite – cellulose based hybrid nanocomposites, which adopts cellulose nanofibers as matrices, has been intensively developed. Among these materials, hybrid nanocomposites consisting of cellulosic fibers and magnetic nanoparticles have recently attracted much attention due to their potential novel applications in biomedicine,...

  3. Polypyrrole-silver Nanocomposite: Synthesis and Characterization

    Directory of Open Access Journals (Sweden)

    D. M. Nerkar

    2016-07-01

    Full Text Available Polypyrrole-Silver (PPy-Ag nanocomposite has been successfully synthesized by the chemical oxidative polymerization of pyrrole with iron (III chloride as an oxidant, in the presence of a colloidal suspension of silver nanoparticles. Turkevich method (Citrate reduction method was used for the synthesis of silver nanoparticles (Ag NPs. The silver nanoparticles were characterized by UV-Visible spectroscopy which showed an absorption band at 423 nm confirming the formation of nanoparticles. PPy-Ag nanocomposite was characterized by Transmission Electron Microscopy (TEM, Scanning Electron Microscopy (SEM, Fourier Transform Infrared Spectroscopy (FTIR and X-ray diffraction (XRD techniques for morphological and structural confirmations. TEM and SEM images revealed that the silver nanoparticles were well dispersed in the PPy matrix. XRD pattern showed that PPy is amorphous but the presence of the peaks at 2q values of 38.24°, 44.57°, 64.51° and 78.45° corresponding to a cubic phase of silver, revealed the incorporation of silver nanoparticles in the PPy matrix. A possible formation mechanism of PPy-Ag nanocomposite was also proposed. The electrical conductivity of PPy-Ag nanocomposite was studied using two probe method. The electrical conductivity of the PPy-Ag nanocomposite prepared was found to be 4.657´10- 2 S/cm, whereas that of pure PPy was found to be 9.85´10-3 S/cm at room temperature (303 K. The value of activation energy (Ea for pure PPy was 0.045 eV while it decreased to 0.034 eV for PPy-Ag nanocomposite. The synthesized nanocomposite powder can be utilized as a potential material for fabrication of gas sensors operating at room temperature.

  4. Systematic comparison of model polymer nanocomposite mechanics.

    Science.gov (United States)

    Xiao, Senbo; Peter, Christine; Kremer, Kurt

    2016-09-13

    Polymer nanocomposites render a range of outstanding materials from natural products such as silk, sea shells and bones, to synthesized nanoclay or carbon nanotube reinforced polymer systems. In contrast to the fast expanding interest in this type of material, the fundamental mechanisms of their mixing, phase behavior and reinforcement, especially for higher nanoparticle content as relevant for bio-inorganic composites, are still not fully understood. Although polymer nanocomposites exhibit diverse morphologies, qualitatively their mechanical properties are believed to be governed by a few parameters, namely their internal polymer network topology, nanoparticle volume fraction, particle surface properties and so on. Relating material mechanics to such elementary parameters is the purpose of this work. By taking a coarse-grained molecular modeling approach, we study an range of different polymer nanocomposites. We vary polymer nanoparticle connectivity, surface geometry and volume fraction to systematically study rheological/mechanical properties. Our models cover different materials, and reproduce key characteristics of real nanocomposites, such as phase separation, mechanical reinforcement. The results shed light on establishing elementary structure, property and function relationship of polymer nanocomposites.

  5. Nanoscratching of nylon 66-based ternary nanocomposites

    International Nuclear Information System (INIS)

    Dasari, Aravind; Yu Zhongzhen; Mai Yiuwing

    2007-01-01

    The nanoscratch behavior of nylon 66/SEBS-g-MA/clay ternary nanocomposites produced by different blending protocols with contrasting microstructures is studied by using atomic force and transmission electron microscopy. A standard diamond Berkovich indenter is used for scratching and a low load of 1 mN, along with a low sliding velocity of 1 μm s -1 , are employed for this purpose. It is shown that in order to resist penetration it is more important to have exfoliated clay in the continuous nylon matrix during nanoscratching than to have the clay in the dispersed soft rubber domains. The results obtained also explain the preferred usage of ternary nanocomposites compared to binary nanocomposites, particularly nylon 66/exfoliated clay nanocomposites. This research extends current basic knowledge and provides new insights on the nature of nanoscale processes that occur during nanoscratching of polymer nanocomposites. Critical questions are raised on the relationships between the penetration depth and material deformation and damage left behind the moving indenter

  6. Cellulose nanofibrils (CNF) filled boron nitride (BN) nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Sulaiman, Hanisah Syed; Hua, Chia Chin; Zakaria, Sarani [School of Applied Physic, Faculty of Science and Technology, Universiti Kebangsaan Malaysia.43600 Bangi, Selangor (Malaysia)

    2015-09-25

    In this study, nanocomposite using cellulose nanofibrils filled with different percentage of boron nitride (CNF-BN) were prepared. The objective of this research is to study the effect of different percentage of BN to the thermal conductivity of the nanocomposite produced. The CNF-BN nanocomposite were characterization by FT-IR, SEM and thermal conductivity. The FT-IR analysis of the CNF-BN nanocomposite shows all the characteristic peaks of cellulose and BN present in all samples. The dispersion of BN in CNF were seen through SEM analysis. The effect of different loading percentage of BN to the thermal conductivity of the nanocomposite were also investigated.

  7. Novel Nanocomposite Materials for Advanced Li-Ion Rechargeable Batteries

    Directory of Open Access Journals (Sweden)

    Chuan Cai

    2009-09-01

    Full Text Available Nanostructured materials lie at the heart of fundamental advances in efficient energy storage and/or conversion, in which surface processes and transport kinetics play determining roles. Nanocomposite materials will have a further enhancement in properties compared to their constituent phases. This Review describes some recent developments of nanocomposite materials for high-performance Li-ion rechargeable batteries, including carbon-oxide nanocomposites, polymer-oxide nanocomposites, metal-oxide nanocomposites, and silicon-based nanocomposites, etc. The major goal of this Review is to highlight some new progress in using these nanocomposite materials as electrodes to develop Li-ion rechargeable batteries with high energy density, high rate capability, and excellent cycling stability.

  8. Tangible nanocomposites with diverse properties for heart valve application

    Science.gov (United States)

    Vignesh Vellayappan, Muthu; Balaji, Arunpandian; Priyadarshini Subramanian, Aruna; Aruna John, Agnes; Jaganathan, Saravana Kumar; Murugesan, Selvakumar; Mohandas, Hemanth; Supriyanto, Eko; Yusof, Mustafa

    2015-06-01

    Cardiovascular disease claims millions of lives every year throughout the world. Biomaterials are used widely for the treatment of this fatal disease. With the advent of nanotechnology, the use of nanocomposites has become almost inevitable in the field of biomaterials. The versatile properties of nanocomposites, such as improved durability and biocompatibility, make them an ideal choice for various biomedical applications. Among the various nanocomposites, polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane, bacterial cellulose with polyvinyl alcohol, carbon nanotubes, graphene oxide and nano-hydroxyapatite nanocomposites have gained popularity as putative choices for biomaterials in cardiovascular applications owing to their superior properties. In this review, various studies performed utilizing these nanocomposites for improving the mechanical strength, anti-calcification potential and hemocompatibility of heart valves are reviewed and summarized. The primary motive of this work is to shed light on the emerging nanocomposites for heart valve applications. Furthermore, we aim to promote the prospects of these nanocomposites in the campaign against cardiovascular diseases.

  9. Nanocomposites with High Thermoelectric Figures of Merit

    Science.gov (United States)

    Chen, Gang (Inventor); Dresselhaus, Mildred (Inventor); Ren, Zhifeng (Inventor)

    2015-01-01

    The present invention is generally directed to nanocomposite thermoelectric materials that exhibit enhanced thermoelectric properties. The nanocomposite materials include two or more components, with at least one of the components forming nano-sized structures within the composite material. The components are chosen such that thermal conductivity of the composite is decreased without substantially diminishing the composite's electrical conductivity. Suitable component materials exhibit similar electronic band structures. For example, a band-edge gap between at least one of a conduction band or a valence band of one component material and a corresponding band of the other component material at interfaces between the components can be less than about 5k(sub B)T, wherein k(sub B) is the Boltzman constant and T is an average temperature of said nanocomposite composition.

  10. Au Based Nanocomposites Towards Plasmonic Applications

    Science.gov (United States)

    Panniello, A.; Curri, M. L.; Placido, T.; Reboud, V.; Kehagias, N.; Sotomayor Torres, C. M.; Mecerreyes, D.; Agostiano, A.; Striccoli, M.

    2010-06-01

    Incorporation of nano-sized metals in polymers can transfer their unique features to the host matrix, providing nanocomposite materials with improved optical, electric, magnetic and mechanical properties. In this work, colloidal Au nanorods have been incorporated into PMMA based random co-polymer, properly functionalized with amino groups and the optical and morphological properties of the resulting nanocomposite have been investigated by spectroscopic and AFM measurements. Au nanorods have demonstrated to preserve the plasmon absorption and to retain morphological features upon the incorporation, thus making the final metal modified polymer composite exploitable for the fabrication of plasmonic devices. The prepared nanocomposites have been then patterned by Nano Imprint Lithography technique in order to demonstrate the viability of the materials towards optical applications.

  11. Nanocomposite Coatings: Preparation, Characterization, Properties, and Applications

    Directory of Open Access Journals (Sweden)

    Phuong Nguyen-Tri

    2018-01-01

    Full Text Available Incorporation of nanofillers into the organic coatings might enhance their barrier performance, by decreasing the porosity and zigzagging the diffusion path for deleterious species. Thus, the coatings containing nanofillers are expected to have significant barrier properties for corrosion protection and reduce the trend for the coating to blister or delaminate. On the other hand, high hardness could be obtained for metallic coatings by producing the hard nanocrystalline phases within a metallic matrix. This article presents a review on recent development of nanocomposite coatings, providing an overview of nanocomposite coatings in various aspects dealing with the classification, preparative method, the nanocomposite coating properties, and characterization methods. It covers potential applications in areas such as the anticorrosion, antiwear, superhydrophobic area, self-cleaning, antifouling/antibacterial area, and electronics. Finally, conclusion and future trends will be also reported.

  12. Microstructural evolution of alumina-zirconia nanocomposites

    International Nuclear Information System (INIS)

    Ojaimi, C.L.; Chinelatto, A.S.A.; Chinelatto, A.L.; Pallone, E.M.J.A.

    2012-01-01

    Ceramic materials have limited use due to their brittleness. The inclusion of nanosized particles in a ceramic matrix, which are called nanocomposites, and ceramic processing control by controlling the grain size and densification can aid in obtaining ceramic products of greater strength and toughness. Studies showed that the zirconia nano inclusions in the matrix of alumina favors an increase in mechanical properties by inhibiting the grain growth of the matrix and not by the mechanism of the transformation toughening phase of zirconia. In this work, the microstructural evolution of alumina nanocomposites containing 15% by volume of nanometric zirconia was studied. From the results it was possible to understand the sintering process of these nanocomposites. (author)

  13. Epoxy Nanocomposites filled with Carbon Nanoparticles.

    Science.gov (United States)

    Martin-Gallego, M; Yuste-Sanchez, V; Sanchez-Hidalgo, R; Verdejo, R; Lopez-Manchado, M A

    2018-01-10

    Over the past decades, the development of high performance lightweight polymer nanocomposites and, in particular, of epoxy nanocomposites has become one the greatest challenges in material science. The ultimate goal of epoxy nanocomposites is to extrapolate the exceptional intrinsic properties of the nanoparticles to the bulk matrix. However, in spite of the efforts, this objective is still to be attained at commercially attractive scales. Key aspects to achieve this are ultimately the full understanding of network structure, the dispersion degree of the nanoparticles, the interfacial adhesion at the phase boundaries and the control of the localization and orientation of the nanoparticles in the epoxy system. In this Personal Account, we critically discuss the state of the art and evaluate the strategies to overcome these barriers. © 2018 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Room temperature magneto-electric coupling in La-Zn doped Ba{sub 1-x}La{sub x}Fe{sub 12-x}Zn{sub x}O{sub 19} (x = 0.0-0.4) hexaferrite

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Pawan; Gaur, Anurag [National Institute of Technology, Department of Physics, Kurukshetra (India)

    2017-12-15

    Barium hexaferrite powder samples with substitution of La{sup +3} at Ba{sup +2} and Zn{sup +2} at Fe{sup +3} site, according to the series formula Ba{sub 1-x}La{sub x}Fe{sub 12-x}Zn{sub x}O{sub 19} (x = 0.0, 0.1, 0.2, 0.3, 0.4) have been prepared by the co-precipitation method. These samples were characterized by X-ray diffractometer (XRD), scanning electron microscopy, Polarization versus electric field loop tracer and vibrating sample magnetometer techniques. XRD patterns and Rietveld refinement indicate the single-phase formation of the magneto-plumbite barium hexaferrite for all the samples. Significant changes in dielectric properties are obtained by the different doping concentration of La and Zn. Ferroelectric loop for all the samples shows the lossy ferroelectric behaviour. Large spontaneous polarization is observed for x = 0.2 sample at room temperature. With increasing La and Zn doping content, the value of saturation magnetization and retentivity increases, and reaches a maximum value of 40.0 emu/gm and 24.0 emu/gm, respectively, for x = 0.2 sample and then decreases. To confirm the magneto-electric coupling, the second-order magneto-electric coupling coefficient β is measured through the dynamic method with the maximum value of ∝ 1.69 x 10{sup -6} mV/cm.Oe{sup 2} for x = 0.2 sample at room temperature. The observations of room temperature magneto-electric coupling in these samples are useful for evolution of new multifunctional devices. (orig.)

  15. Effect of calcination temperature on microstructure, dielectric, magnetic and optical properties of Ba{sub 0.7}La{sub 0.3}Fe{sub 11.7}Co{sub 0.3}O{sub 19} hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Kaur, Talwinder [Department of Physics, Lovely Professional University, Phagwara, Punjab 144411 (India); Kaur, Barjinder [Department of Physics, National Institute of Technology, Jalandhar 144011 (India); Bhat, Bilal H. [Department of Physics, University of Kashmir, 190006 (India); Kumar, Sachin [Department of Chemistry, Guru Nanak Dev University, Amritsar 143005 (India); Srivastava, A.K., E-mail: srivastava_phy@yahoo.co.in [Department of Physics, Lovely Professional University, Phagwara, Punjab 144411 (India)

    2015-01-01

    M-type barium hexaferrite Ba{sub 0.7}La{sub 0.3}Fe{sub 11.7}Co{sub 0.3}O{sub 19} (BaLCM) powder, synthesized using sol gel auto combustion method, heat treated at 700, 900, 1100 and 1200 °C. X ray diffraction (XRD) powder patterns of heat treated samples show the formation of pure phase of M-type hexaferrite after 700 °C. Thermo gravimetric analysis (TGA) reveals that the weight loss of BaLCM becomes constant after 680 °C. The presence of two prominent peaks, at 432 cm{sup −1} and 586 cm{sup −1} in Fourier Transform Infrared Spectroscopy (FT-IR) spectra, gives the idea of formation of M-type hexaferrites. The M–H curve obtained from Vibrating Sample Magnetometer (VSM) were used to calculate saturation magnetization (M{sub S}), retentivity (M{sub r}), squareness ration (SR) and coercivity (H{sub c}). The maximum value of coercivity (5602 Oe) is found at 900 °C. The band gap dependency on temperature was studied using UV–vis NIR spectroscopy. The dielectric constant has been found to be high at low frequency but it decreases with increase in frequency. Such kind of dielectric behavior is explained on the basis of Koop's phenomenological theory and Maxwell Wagner theory.

  16. Ethylene-Octene Copolymers/Organoclay Nanocomposites: Preparation and Properties

    Directory of Open Access Journals (Sweden)

    Alice Tesarikova

    2016-01-01

    Full Text Available Two ethylene-octene copolymers with 17 and 45 wt.% of octene (EOC-17 and EOC-45 were compared in nanocomposites with Cloisite 93A. EOC-45 nanocomposites have a higher elongation at break. Dynamical mechanical analysis (DMA showed a decrease of tan⁡δ with frequency for EOC-17 nanocomposites, but decrease is followed by an increase for EOC-45 nanocomposites; DMA showed also increased modulus for all nanocomposites compared to pure copolymers over a wide temperature range. Barrier properties were improved about 100% by addition of organoclay; they were better for EOC-17 nanocomposites due to higher crystallinity. X-ray diffraction (XRD together with transmission electron microscopy (TEM showed some intercalation for EOC-17 but much better dispersion for EOC-45 nanocomposites. Differential scanning calorimetry (DSC showed increased crystallization temperature Tc for EOC-17 nanocomposite (aggregates acted as nucleation agents but decrease Tc for EOC-45 nanocomposite together with greatly influenced melting peak. Accelerated UV aging showed smaller C=O peak for EOC-45 nanocomposites.

  17. A novel piezoresistive polymer nanocomposite MEMS accelerometer

    International Nuclear Information System (INIS)

    Seena, V; Hari, K; Prajakta, S; Ramgopal Rao, V; Pratap, Rudra

    2017-01-01

    A novel polymer MEMS (micro electro mechanical systems) accelerometer with photo-patternable polymer nanocomposite as a piezoresistor is presented in this work. Polymer MEMS Accelerometer with beam thicknesses of 3.3 µ m and embedded nanocomposite piezoresistive layer having a gauge factor of 90 were fabricated. The photosensitive nanocomposite samples were prepared and characterized for analyzing the mechanical and electrical properties and thereby ensuring proper process parameters for incorporating the piezoresistive layer into the polymer MEMS accelerometer. The microfabrication process flow and unit processes followed are extremely low cost with process temperatures below 100 °C. This also opens up a new possibility for easy integration of such polymer MEMS with CMOS (complementary metal oxide semiconductor) devices and circuits. The fabricated devices were characterized using laser Doppler vibrometer (LDV) and the devices exhibited a resonant frequency of 10.8 kHz and a response sensitivity of 280 nm g −1 at resonance. The main focus of this paper is on the SU-8/CB nanocomposite piezoresistive MEMS accelerometer technology development which covers the material and the fabrication aspects of these devices. CoventorWare FEA analysis performed using the extracted material properties from the experimental characterization which are in close agreement to performance parameters of the fabricated devices is also discussed. The simulated piezoresistive polymer MEMS devices showed an acceleration sensitivity of 126 nm g −1 and 82 ppm of Δ R / R per 1 g of acceleration. (paper)

  18. Bioinspired Nanocomposite Hydrogels with Highly Ordered Structures.

    Science.gov (United States)

    Zhao, Ziguang; Fang, Ruochen; Rong, Qinfeng; Liu, Mingjie

    2017-12-01

    In the human body, many soft tissues with hierarchically ordered composite structures, such as cartilage, skeletal muscle, the corneas, and blood vessels, exhibit highly anisotropic mechanical strength and functionality to adapt to complex environments. In artificial soft materials, hydrogels are analogous to these biological soft tissues due to their "soft and wet" properties, their biocompatibility, and their elastic performance. However, conventional hydrogel materials with unordered homogeneous structures inevitably lack high mechanical properties and anisotropic functional performances; thus, their further application is limited. Inspired by biological soft tissues with well-ordered structures, researchers have increasingly investigated highly ordered nanocomposite hydrogels as functional biological engineering soft materials with unique mechanical, optical, and biological properties. These hydrogels incorporate long-range ordered nanocomposite structures within hydrogel network matrixes. Here, the critical design criteria and the state-of-the-art fabrication strategies of nanocomposite hydrogels with highly ordered structures are systemically reviewed. Then, recent progress in applications in the fields of soft actuators, tissue engineering, and sensors is highlighted. The future development and prospective application of highly ordered nanocomposite hydrogels are also discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Probing polymer nanocomposite morphology by small angle ...

    Indian Academy of Sciences (India)

    Polyamide nanocomposite films were prepared from nanometer-sized silica particles having particle radius of gyration (g) of about 66 Å and trimesoyl chloride--phenylene diamine-based polyamides having macromolecular units of about 100-140 Å. The nanoscale morphology of the samples was characterized using ...

  20. Polymer nanocomposites for lithium battery applications

    Science.gov (United States)

    Sandi-Tapia, Giselle; Gregar, Kathleen Carrado

    2006-07-18

    A single ion-conducting nanocomposite of a substantially amorphous polyethylene ether and a negatively charged synthetic smectite clay useful as an electrolyte. Excess SiO2 improves conductivity and when combined with synthetic hectorite forms superior membranes for batteries. A method of making membranes is also disclosed.

  1. Development of nanocomposites based on potato starch

    International Nuclear Information System (INIS)

    Brito, Luciana Macedo; Tavares, Maria Ines Bruno

    2013-01-01

    Nanocomposites of potato starch were prepared by the solution intercalation method with the addition of organically modified montmorillonite clay (Viscogel B and unmodified sodic clay (NT25) as well as modified and unmodified silica (R972 and A200, respectively), using water as the solvent. The nanocomposites were characterized by conventional techniques of X-ray diffraction and thermogravimetric analysis. They were also characterized using the non-conventional low-field nuclear magnetic resonance, which is an effective alternative technique for characterizing nanocomposites. This technique allows one to investigate dispersion of nanofillers by the degree of intercalation and/or exfoliation, in addition to determine the distribution of nanoparticles in the polymer matrix and modifications of the molecular mobility of these fillers. The nanostructured materials obtained with the clays presented good dispersion and formation of mixed nanomaterials, with different degrees of intercalation and exfoliation. The mobility of the material decreased upon adding silica in the starch matrix, which applied to both types of silica. From the TGA technique, a slight increase in thermal stability of the nanocomposite was noted in relation to the starch matrix. (author)

  2. Poly(.epsilon.-caprolactone)-clay nanocomposites

    Czech Academy of Sciences Publication Activity Database

    Sedničková, M.; Jochec-Mošková, D.; Janigová, I.; Kronek, J.; Jankovič, L.; Šlouf, Miroslav; Chodák, I.

    2017-01-01

    Roč. 13, č. 1 (2017), s. 111-112 ISSN 1336-7242. [Zjazd chemikov /69./. 11.09.2017-15.09.2017, Horný Smokovec] Institutional support: RVO:61389013 Keywords : nanocomposites * montmorillonite Subject RIV: CD - Macromolecular Chemistry

  3. A new luminescent montmorillonite/borane nanocomposite

    Czech Academy of Sciences Publication Activity Database

    Kolská, Z.; Matoušek, J.; Čapková, P.; Braborec, Jakub; Benkocká, M.; Černá, H.; Londesborough, Michael Geoffrey Stephen

    2015-01-01

    Roč. 118, DEC (2015), s. 295-300 ISSN 0169-1317 Institutional support: RVO:61388980 Keywords : Luminophore * Montmorillonite/borane nanocomposite * X-ray photoelectron spectroscopy * X-ray diffraction * UV–Vis spectra Subject RIV: CA - Inorganic Chemistry Impact factor: 2.586, year: 2015

  4. clay nanocomposite by solution intercalation technique

    Indian Academy of Sciences (India)

    Polymer–clay nanocomposites of commercial polystyrene (PS) and clay laponite were prepared via solution intercalation technique. Laponite was modified suitably with the well known cationic surfactant cetyltrimethyl ammonium bromide by ion-exchange reaction to render laponite miscible with hydrophobic PS.

  5. Biodegradation behaviors of cellulose nanocrystals -PVA nanocomposites

    Directory of Open Access Journals (Sweden)

    Mahdi Rohani

    2014-11-01

    Full Text Available In this research, biodegradation behaviors of cellulose nanocrystals-poly vinyl alcohol nanocomposites were investigated. Nanocomposite films with different filler loading levels (3, 6, 9 and 12% by wt were developed by solvent casting method. The effect of cellulose nanocrystals on the biodegradation behaviors of nanocomposite films was studied. Water absorption and water solubility tests were performed by immersing specimens into distilled water. The characteristic parameter of diffusion coefficient and maximum moisture content were determined from the obtained water absorption curves. The water absorption behavior of the nanocomposites was found to follow a Fickian behavior. The maximum water absorption and diffusion coefficients were decreased by increasing the cellulose nanocrystals contents, however the water solubility decrease. The biodegradability of the films was investigated by immersing specimens into cellulase enzymatic solution as well as by burial in soil. The results showed that adding cellulose nanocrystals increase the weight loss of specimens in enzymatic solution but decrease it in soil media. The limited biodegradability of specimens in soil media attributed to development of strong interactions with solid substrates that inhibit the accessibility of functional groups. Specimens with the low degree of hydrolysis underwent extensive biodegradation in both enzymatic and soil media, whilst specimens with the high degree of hydrolysis showed recalcitrance to biodegradation under those conditions.

  6. PCL/MWCNT Nanocomposites as Nanosensors

    Science.gov (United States)

    Grozdanov, Anita; Buzarovska, Alexandra; Avella, Maurizio; Errico, Maria E.; Gentile, Gennaro

    Due to the unique electronic, metallic and structural properties of carbon nanotubes (CNTs) as compared to other materials, researchers focused on utilizing these characteristics for engineering applications such as actuators, hydrogen storage materials, chemical sensors and nanoelectronic devices. Many papers have been published utilizing CNTs as the sensing material in pressure, flow, thermal, gas, optical, mass, strain, stress, chemical and biological sensors. Amongst many of their superior electro-mechanical properties, the piezoresistive effect in CNTs is attractive for designing strain sensors. When CNTs are subjected to a mechanical strain, a change in their chirality leads to modulation of the conductance. In this paper, a novel carbon nanotube/biopolymer nanocomposite was used to develop a piezoresistive strain nano bio-sensor. A biocompatible polymer matrix has been used to provide good interfacial bonding between the carbon nanotubes. Multi-walled carbon nanotubes (MWCNT, diameter d = 30-50 nm, purity >95%) have been used for the preparation of polycaprolactone (PCL)-based nanocomposites (PCL/MWCNT). The nanocomposites were prepared by mixing the MWCNTs and PCL in a tetrahydrofuran solution for 24 h. Characterization of the PCL/MWCNTs nanocomposite films was performed by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier-transform infrared (FTIR) and scanning electron microscopy (SEM), as well as by mechanical and electrical measurements.

  7. Cycloolefin copolymer/fumed silica nanocomposites

    Czech Academy of Sciences Publication Activity Database

    Dorigato, A.; Pegoretti, A.; Fambri, L.; Šlouf, Miroslav; Kolařík, Jan

    2011-01-01

    Roč. 119, č. 6 (2011), s. 3393-3402 ISSN 0021-8995 R&D Projects: GA ČR GA106/09/1348 Institutional research plan: CEZ:AV0Z40500505 Keywords : creep * nanocomposites * polyolefins Subject RIV: JI - Composite Materials Impact factor: 1.289, year: 2011

  8. Nanocomposites in food packaging – A review

    Science.gov (United States)

    A nanocomposite is a multiphase material derived from the combination of two or more components, including a matrix (continuous phase) and a discontinuous nano-dimensional phase with at least one nano-sized dimension (i.e. less than 100 nm). The main types of nanostructures are presented in this ch...

  9. octamethyl-polyhedral oligomeric silsesquioxanes nanocomposites ...

    Indian Academy of Sciences (India)

    In this study, biodegradable poly(p-dioxanone) (PPDO)/octamethyl-polyhedral oligomeric silsesquioxanes (ome-POSS) nanocomposites were fabricated by the simple solution casting method with various ome-POSS loadings. Scanning electron microscopic observations indicate that ome-POSS is well dispersed in the ...

  10. In situ SU-8 silver nanocomposites

    Directory of Open Access Journals (Sweden)

    Søren V. Fischer

    2015-07-01

    Full Text Available Nanocomposite materials containing metal nanoparticles are of considerable interest in photonics and optoelectronics applications. However, device fabrication of such materials always encounters the challenge of incorporation of preformed nanoparticles into photoresist materials. As a solution to this problem, an easy new method of fabricating silver nanocomposites by an in situ reduction of precursors within the epoxy-based photoresist SU-8 has been developed. AgNO3 dissolved in acetonitrile and mixed with the epoxy-based photoresist SU-8 forms silver nanoparticles primarily during the pre- and post-exposure soft bake steps at 95 °C. A further high-temperature treatment at 300 °C resulted in the formation of densely homogeneously distributed silver nanoparticles in the photoresist matrix. No particle growth or agglomeration of nanoparticles is observed at this point. The reported new in situ silver nanocomposite materials can be spin coated as homogeneous thin films and structured by using UV lithography. A resolution of 5 µm is achieved in the lithographic process. The UV exposure time is found to be independent of the nanoparticle concentration. The fabricated silver nanocomposites exhibit high plasmonic responses suitable for the development of new optoelectronic and optical sensing devices.

  11. Cyclic olefin copolymer-silica nanocomposites foams

    Czech Academy of Sciences Publication Activity Database

    Pegoretti, A.; Dorigato, A.; Biani, A.; Šlouf, Miroslav

    2016-01-01

    Roč. 51, č. 8 (2016), s. 3907-3916 ISSN 0022-2461 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : cyclic olefin copolymer * nanocomposites * silica Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.599, year: 2016

  12. Magnetic graphene based nanocomposite for uranium scavenging

    Energy Technology Data Exchange (ETDEWEB)

    El-Maghrabi, Heba H. [Egyptian Petroleum Research Institute, 11727, Cairo (Egypt); Abdelmaged, Shaimaa M. [Nuclear Materials Authority, 6530 P.O. Box Maadi, Cairo (Egypt); Nada, Amr A. [Egyptian Petroleum Research Institute, 11727, Cairo (Egypt); Zahran, Fouad, E-mail: f.zahran@quim.ucm.es [Faculty of Science, Helwan University, 11795, Cairo (Egypt); El-Wahab, Saad Abd; Yahea, Dena [Faculty of Science, Ain shams University, Cairo (Egypt); Hussein, G.M.; Atrees, M.S. [Nuclear Materials Authority, 6530 P.O. Box Maadi, Cairo (Egypt)

    2017-01-15

    Graphical abstract: Graphical representation of U{sup 6+} adsorption on Magnetic Ferberite-Graphene Nanocomposite. - Highlights: • Synthesis of new magnetic wolframite bimetallic nanostructure on graphene. • A promising adsorption capacity of 455 mg/g was recorded for FG-20 within 60 min at room temperature. • The uranium removal was followed pseudo-second order kinetics and Langmuir isotherm. - Abstract: Magnetic graphene based ferberite nanocomposite was tailored by simple, green, low cost and industrial effective method. The microstructure and morphology of the designed nanomaterials were examined via XRD, Raman, FTIR, TEM, EDX and VSM. The prepared nanocomposites were introduced as a novel adsorbent for uranium ions scavenging from aqueous solution. Different operating conditions of time, pH, initial uranium concentration, adsorbent amount and temperature were investigated. The experimental data shows a promising adsorption capacity. In particular, a maximum value of 455 mg/g was obtained within 60 min at room temperature with adsorption efficiency of 90.5%. The kinetics and isotherms adsorption data were fitted with the pseudo-second order model and Langmuir equation, respectively. Finally, the designed nanocomposites were found to have a great degree of sustainability (above 5 times of profiteering) with a complete maintenance of their parental morphology and adsorption capacity.

  13. Development of multifunctional fluoroelastomers based on nanocomposites

    International Nuclear Information System (INIS)

    Zen, Heloisa Augusto

    2015-01-01

    The fluoropolymers are known for their great mechanical properties, high thermal stability and resistance to aggressive chemical environment, and because of those properties they are widely used in industries, such as automobile, petroleum, chemistry, manufacturing, among others. To improve the thermal properties and gases barrier of the polymeric matrix, the incorporation of nanoparticle is used, this process permits the polymer to maintain their own characteristics and acquire new properties of nanoparticle. Because of those properties, the structural and morphological modification of fluoropolymers are very hard to be obtained through traditional techniques, in order to surmount this difficulty, the ionizing radiation is a well-known and effective method to modify fluoropolymers structures. In this thesis a nanocomposite polymeric based on fluoroelastomer (FKM) was developed and incorporated with four different configurations of nanoparticles: clay Cloisite 15A, POSS 1159, POSS 1160 and POSS 1163. After the nanocomposites films were obtained, a radiation induced grafting process was carried out, followed by sulfonation in order to obtain a ionic exchanged membrane. The effect of nanoparticle incorporation and the ionizing radiation onto films were characterized by X-ray diffraction, thermal and mechanical analysis, scanning electron microscopy and swelling; and the membranes were evaluated by degree of grafting, ionic exchange capacity and swelling. After the films were characterized, the crosslinking effect was observed to be predominant for the nanocomposites irradiated before the vulcanization, whereas the degradation was the predominant effect in the nanocomposites irradiated after vulcanization. (author)

  14. Enhancement in performance of polycarbazole-graphene nanocomposite Schottky diode

    International Nuclear Information System (INIS)

    Pandey, Rajiv K.; Singh, Arun Kumar; Prakash, Rajiv

    2013-01-01

    We report formation of polycarbazole (PCz)–graphene nanocomposite over indium tin oxide (ITO) coated glass substrate using electrochemical technique for fabrication of high performance Schottky diodes. The synthesized nanocomposite is characterized before fabrication of devices for confirmation of uniform distribution of graphene nanosheets in the polymer matrix. Pure PCz and PCz-graphene nanocomposites based Schottky diodes are fabricated of configuration Al/PCz/ITO and Al/PCz-graphene nanocomposite/ITO, respectively. The current density–voltage (J-V) characteristics and diode performance parameters (such as the ideality factor, barrier height, and reverse saturation current density) are compared under ambient condition. Al/PCz-graphene nanocomposite/ITO device exhibits better ideality factor in comparison to the device formed using pure PCz. It is also observed that the Al/PCz-graphene nanocomposite/ITO device shows large forward current density and low turn on voltage in comparison to Al/PCz/ITO device

  15. Graphene oxide - Polyvinyl alcohol nanocomposite based electrode material for supercapacitors

    Science.gov (United States)

    Pawar, Pranav Bhagwan; Shukla, Shobha; Saxena, Sumit

    2016-07-01

    Supercapacitors are high capacitive energy storage devices and find applications where rapid bursts of power are required. Thus materials offering high specific capacitance are of fundamental interest in development of these electrochemical devices. Graphene oxide based nanocomposites are mechanically robust and have interesting electronic properties. These form potential electrode materials efficient for charge storage in supercapacitors. In this perspective, we investigate low cost graphene oxide based nanocomposites as electrode material for supercapacitor. Nanocomposites of graphene oxide and polyvinyl alcohol were synthesized in solution phase by integrating graphene oxide as filler in polyvinyl alcohol matrix. Structural and optical characterizations suggest the formation of graphene oxide and polyvinyl alcohol nanocomposites. These nanocomposites were found to have high specific capacitance, were cyclable, ecofriendly and economical. Our studies suggest that nanocomposites prepared by adding 0.5% wt/wt of graphene oxide in polyvinyl alcohol can be used an efficient electrode material for supercapacitors.

  16. Novel toughened polylactic acid nanocomposite: Mechanical, thermal and morphological properties

    International Nuclear Information System (INIS)

    Balakrishnan, Harintharavimal; Hassan, Azman; Wahit, Mat Uzir; Yussuf, A.A.; Razak, Shamsul Bahri Abdul

    2010-01-01

    The objective of the study is to develop a novel toughened polylactic acid (PLA) nanocomposite. The effects of linear low density polyethylene (LLDPE) and organophilic modified montmorillonite (MMT) on mechanical, thermal and morphological properties of PLA were investigated. LLDPE toughened PLA nanocomposites consisting of PLA/LLDPE blends, of composition 100/0 and 90/10 with MMT content of 2 phr and 4 phr were prepared. The Young's and flexural modulus improved with increasing content of MMT indicating that MMT is effective in increasing stiffness of LLDPE toughened PLA nanocomposite even at low content. LLDPE improved the impact strength of PLA nanocomposites with a sacrifice of tensile and flexural strength. The tensile and flexural strength also decreased with increasing content of MMT in PLA/LLDPE nanocomposites. The impact strength and elongation at break of LLDPE toughened PLA nanocomposites also declined steadily with increasing loadings of MMT. The crystallization temperature and glass transition temperature dropped gradually while the thermal stability of PLA improved with addition of MMT in PLA/LLDPE nanocomposites. The storage modulus of PLA/LLDPE nanocomposites below glass transition temperature increased with increasing content of MMT. X-ray diffraction and transmission electron microscope studies revealed that an intercalated LLDPE toughened PLA nanocomposite was successfully prepared at 2 phr MMT content.

  17. Nanocomposites chitosan/montmorillonite for drug delivery system

    International Nuclear Information System (INIS)

    Braga, Carla R. Costa; Barbosa, Rossemberg C.; Lima, Rosemary S. Cunha; Fook, Marcus V. Lia; Silva, Suedina M. Lima

    2009-01-01

    In drugs delivery system the incorporation of an inorganic nanophase in polymer matrix, i.e. production of an inorganic-organic nanocomposite is an attractive alternative to obtain a constant release rate for a prolonged time. This study was performed to obtain films of nanocomposites Chitosan/montmorillonite intercalation by the technique of solution in the proportions of 1:1, 5:1 and 10:1. The nanocomposites were characterized by infrared spectroscopy, X-ray diffraction and thermogravimetric analysis. The results indicated that the feasibility of obtaining films of nanocomposites exfoliate. Among the suggested applications for films developed in this study includes them use for drugs delivery system. (author)

  18. Development of polymer nanocomposites with regional bentonite clay

    International Nuclear Information System (INIS)

    Araujo, Edcleide M.; Leite, Amanda M.D.; Paz, Rene A. da; Medeiros, Keila M. de; Melo, Tomas J.A.; Barbosa, Josiane D.V.; Barbosa, Renata

    2011-01-01

    nanocomposites with regional bentonite clay were prepared by melt intercalation technique. The clays were studied without modification and modified with four quaternary ammonium salts. It was evidenced by X-ray diffraction that salts were incorporated into the clay structure thus confirming its organophilization. The nanocomposites were evaluated by means of thermal mechanic and flammability tests where presented properties significantly improved their pure polymers. The process of biodegradation of obtained bio nanocomposites was accelerated by the presence of clay. The produced membranes from nanocomposites have potential in the oil-water separation. (author)

  19. Diamond like carbon nanocomposites with embedded metallic nanoparticles

    Science.gov (United States)

    Tamulevičius, Sigitas; Meškinis, Šarūnas; Tamulevičius, Tomas; Rubahn, Horst-Günter

    2018-02-01

    In this work we present an overview on structure formation, optical and electrical properties of diamond like carbon (DLC) based metal nanocomposites deposited by reactive magnetron sputtering and treated by plasma and laser ablation methods. The influence of deposition mode and other technological conditions on the properties of the nanosized filler, matrix components and composition were studied systematically in relation to the final properties of the nanocomposites. Applications of the nanocomposites in the development of novel biosensors combining resonance response of wave guiding structures in DLC based nanocomposites as well as plasmonic effects are also presented.

  20. Multifunctional Nanocomposites for Breast Cancer Imaging and Therapy

    National Research Council Canada - National Science Library

    Gayen, Swapan K; Balogh-Nair, Valeria

    2008-01-01

    The objective of the research was to explore the feasibility of concomitant detection and of breast cancer through the development of multifunctional nanocomposites that will enable early detection...

  1. Photonic structures based on hybrid nanocomposites

    Science.gov (United States)

    Husaini, Saima

    In this thesis, photonic structures embedded with two types of nanomaterials, (i) quantum dots and (ii) metal nanoparticles are studied. Both of these exhibit optical and electronic properties different from their bulk counterpart due to their nanoscale physical structure. By integrating these nanomaterials into photonic structures, in which the electromagnetic field can be confined and controlled via modification of geometry and composition, we can enhance their linear and nonlinear optical properties to realize functional photonic structures. Before embedding quantum dots into photonic structures, we study the effect of various host matrices and fabrication techniques on the optical properties of the colloidal quantum dots. The two host matrices of interest are SU8 and PMMA. It is shown that the emission properties of the quantum dots are significantly altered in these host matrices (especially SU8) and this is attributed to a high rate of nonradiative quenching of the dots. Furthermore, the effects of fabrication techniques on the optical properties of quantum dots are also investigated. Finally a microdisk resonator embedded with quantum dots is fabricated using soft lithography and luminescence from the quantum dots in the disk is observed. We investigate the absorption and effective index properties of silver nanocomposite films. It is shown that by varying the fill factor of the metal nanoparticles and fabrication parameters such as heating time, we can manipulate the optical properties of the metal nanocomposite. Optimizing these parameters, a silver nanocomposite film with a 7% fill factor is prepared. A one-dimensional photonic crystal consisting of alternating layers of the silver nanocomposite and a polymer (Polymethyl methacrylate) is fabricated using spin coating and its linear and nonlinear optical properties are investigated. Using reflectivity measurements we demonstrate that the one-dimensional silver-nanocomposite-dielectric photonic crystal

  2. Synthesis, thermal properties and applications of polymer-clay nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Meneghetti, Paulo [Chemical Engineering Department, Case Western Reserve University, 10900 Euclid Ave. Cleveland, OH 44106 (United States); Qutubuddin, Syed [Chemical Engineering Department, Case Western Reserve University, 10900 Euclid Ave. Cleveland, OH 44106 (United States)]. E-mail: sxq@case.edu

    2006-03-15

    Polymer-clay nanocomposites constitute a new class of materials in which the polymer matrix is reinforced by uniformly dispersed inorganic particles (usually 10 wt.% or less) having at least one dimension in the nanometer scale. Nanocomposites exhibit improved properties when compared to pure polymer or conventional composites, such as enhanced mechanical and thermal properties, reduced gas permeability, and improved chemical stability. In this work, the synthesis of poly(methyl methacrylate) (PMMA)/clay nanocomposites is described via two methods: in situ and emulsion polymerization. The in situ technique follows a two-step process: ion-exchange of the clay to make it hydrophobic, and polymerization after dispersing the functionalized clay in the monomer. The emulsion technique combines the two steps of the in situ method into one by conducting ion-exchange and polymerization in an aqueous medium in the same reactor. The clay (montmorillonite, MMT) is functionalized with a zwitterionic surfactant, octadecyl-dimethyl betaine (C18DMB). Partially exfoliated nanocomposite, observed by transmission electron microscopy (TEM), was obtained by emulsion polymerization with 10 wt.% clay. Glass transition temperature (T {sub g}) of this nanocomposite was 18 deg. C higher than pure PMMA. With the same clay content, in situ polymerization produced intercalated nanocomposite with T {sub g} 10 deg. C lower than the emulsion nanocomposite. The storage modulus of partially exfoliated nanocomposite was superior to the intercalated structure and to the pure polymer. Using nanocomposite technology, novel PMMA nanocomposite gel electrolytes were synthesized exhibiting improved ionic conductivity and stable lithium interfacial resistance. Nanocomposites can also be used for gas storage and packaging applications as demonstrated by high barrier polymer-clay films.

  3. Synthesis, thermal properties and applications of polymer-clay nanocomposites

    International Nuclear Information System (INIS)

    Meneghetti, Paulo; Qutubuddin, Syed

    2006-01-01

    Polymer-clay nanocomposites constitute a new class of materials in which the polymer matrix is reinforced by uniformly dispersed inorganic particles (usually 10 wt.% or less) having at least one dimension in the nanometer scale. Nanocomposites exhibit improved properties when compared to pure polymer or conventional composites, such as enhanced mechanical and thermal properties, reduced gas permeability, and improved chemical stability. In this work, the synthesis of poly(methyl methacrylate) (PMMA)/clay nanocomposites is described via two methods: in situ and emulsion polymerization. The in situ technique follows a two-step process: ion-exchange of the clay to make it hydrophobic, and polymerization after dispersing the functionalized clay in the monomer. The emulsion technique combines the two steps of the in situ method into one by conducting ion-exchange and polymerization in an aqueous medium in the same reactor. The clay (montmorillonite, MMT) is functionalized with a zwitterionic surfactant, octadecyl-dimethyl betaine (C18DMB). Partially exfoliated nanocomposite, observed by transmission electron microscopy (TEM), was obtained by emulsion polymerization with 10 wt.% clay. Glass transition temperature (T g ) of this nanocomposite was 18 deg. C higher than pure PMMA. With the same clay content, in situ polymerization produced intercalated nanocomposite with T g 10 deg. C lower than the emulsion nanocomposite. The storage modulus of partially exfoliated nanocomposite was superior to the intercalated structure and to the pure polymer. Using nanocomposite technology, novel PMMA nanocomposite gel electrolytes were synthesized exhibiting improved ionic conductivity and stable lithium interfacial resistance. Nanocomposites can also be used for gas storage and packaging applications as demonstrated by high barrier polymer-clay films

  4. Characterization of SWNT based Polystyrene Nanocomposites

    Science.gov (United States)

    Mitchell, Cynthia; Bahr, Jeffrey; Tour, James; Arepalli, Sivaram; Krishnamoorti, Ramanan

    2003-03-01

    Polystyrene nanocomposites with functionalized single walled carbon nanotubes (SWNTs), prepared by the in-situ generation and addition of organic diazonium compounds, were characterized using a range of structural and dynamic methods. These were contrasted to the properties of polystyrene composites prepared with unfunctionalized SWNTs at the same loadings. The functionalized nanocomposites demonstrated a percolated SWNT network structure at concentrations of 1 vol SWNT based composites at similar loadings of SWNT exhibited behavior comparable to that of the unfilled polymer. This formation of the SWNT network structure is because of the improved compatibility between the SWNTs and the polymer matrix due to the functionalization. Further structural evidence for the compatibility of the modified SWNTs and the polymer matrix will be discussed in the presentation.

  5. Investigation on Curcumin nanocomposite for wound dressing.

    Science.gov (United States)

    Venkatasubbu, G Devanand; Anusuya, T

    2017-05-01

    Curcuma longa (turmeric) has a long history of use in medicine as a treatment for inflammatory conditions. The primary active constituent of turmeric and the one responsible for its vibrant yellow color is curcumin. Curcumin is used for treatment of wound and inflammation. It had antimicrobial and antioxidant property. It has low intrinsic toxicity and magnificent properties like with comparatively lesser side-effects. Cotton cloth is one of the most successful wound dressings which utilize the intrinsic properties of cotton fibers. Modern wound dressings, however, require other properties such as antibacterial and moisture maintaining capabilities. In this study, conventional cotton cloth was coated with Curcumin composite for achieving modern wound dressing properties. Curcumin nanocomposite is characterized. The results show that coated cotton cloth with Curcumin nanocomposite has increased drying time (74%) and water absorbency (50%). Furthermore, they show antibacterial efficiency against bacterial species present in wounds. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Progress of Nanocomposite Membranes for Water Treatment

    Directory of Open Access Journals (Sweden)

    Claudia Ursino

    2018-04-01

    Full Text Available The use of membrane-based technologies has been applied for water treatment applications; however, the limitations of conventional polymeric membranes have led to the addition of inorganic fillers to enhance their performance. In recent years, nanocomposite membranes have greatly attracted the attention of scientists for water treatment applications such as wastewater treatment, water purification, removal of microorganisms, chemical compounds, heavy metals, etc. The incorporation of different nanofillers, such as carbon nanotubes, zinc oxide, graphene oxide, silver and copper nanoparticles, titanium dioxide, 2D materials, and some other novel nano-scale materials into polymeric membranes have provided great advances, e.g., enhancing on hydrophilicity, suppressing the accumulation of pollutants and foulants, enhancing rejection efficiencies and improving mechanical properties and thermal stabilities. Thereby, the aim of this work is to provide up-to-date information related to those novel nanocomposite membranes and their contribution for water treatment applications.

  7. Metal-polymer nanocomposites for functional applications

    Energy Technology Data Exchange (ETDEWEB)

    Faupel, Franz; Zaporojtchenko, Vladimir; Strunskus, Thomas [Christian-Albrechts-Universitaet zu Kiel (Germany). Institut fuer Materialwissenschaft - Materialverbunde; Elbahri, Mady [Christian-Albrechts-Universitaet zu Kiel (Germany). Institut fuer Materialwissenschaft - Nanochemistry and Engineering

    2010-12-15

    Nanocomposites combine favorable features of the constituents on the nanoscale to obtain new functionalities. The present paper is concerned with the preparation of polymer-based nanocomposites consisting of metal nanoparticles in a polymer matrix and the resulting functional properties. Emphasis is placed on vapor phase deposition which inter alia allows the incorporation of alloy clusters with well defined composition and tailored filling factor profiles. Examples discussed here include optical composites with tuned particle surface plasmon resonances for plasmonic applications, magnetic high frequency materials with cut-off frequencies well above 1 GHz, sensors that are based on the dramatic change in the electronic properties near the percolation threshold, and antibacterial coatings which benefit from the large effective surface of nanoparticles and the increased chemical potential which both strongly enhance ion release. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Progress of Nanocomposite Membranes for Water Treatment.

    Science.gov (United States)

    Ursino, Claudia; Castro-Muñoz, Roberto; Drioli, Enrico; Gzara, Lassaad; Albeirutty, Mohammad H; Figoli, Alberto

    2018-04-03

    The use of membrane-based technologies has been applied for water treatment applications; however, the limitations of conventional polymeric membranes have led to the addition of inorganic fillers to enhance their performance. In recent years, nanocomposite membranes have greatly attracted the attention of scientists for water treatment applications such as wastewater treatment, water purification, removal of microorganisms, chemical compounds, heavy metals, etc. The incorporation of different nanofillers, such as carbon nanotubes, zinc oxide, graphene oxide, silver and copper nanoparticles, titanium dioxide, 2D materials, and some other novel nano-scale materials into polymeric membranes have provided great advances, e.g., enhancing on hydrophilicity, suppressing the accumulation of pollutants and foulants, enhancing rejection efficiencies and improving mechanical properties and thermal stabilities. Thereby, the aim of this work is to provide up-to-date information related to those novel nanocomposite membranes and their contribution for water treatment applications.

  9. Electrochemical performance of graphene-polyethylenedioxythiophene nanocomposites

    International Nuclear Information System (INIS)

    Chen, Yan; Xu, Jianhua; Mao, Yunwu; Yang, Yajie; Yang, Wenyao; Li, Shibin

    2013-01-01

    Highlights: • A facile vapor-phase polymerization method is used to deposit PEDOT on graphene. • The graphene-PEDOT composite films exhibit better capacitive retention capability. • This simple technique has been developed to produce highly ordered thin films. -- Abstract: We propose a facile vapor-phase polymerization (VPP) method used to deposit graphene (G)-polyethylene dioxythiophene (PEDOT) nanocomposite film for electrode materials of electrochemical capacitor. This type of conductive polymer nanocomposite improves the performance of electrochemical capacitor. The specific discharge capacitance of G-PEDOT film is higher than that of pure PEDOT electrode. The G-PEDOT electrode also exhibits better capacitive retention capability after 1000 charge–discharge cycles

  10. Potential of Starch Nanocomposites for Biomedical Applications

    Science.gov (United States)

    Zakaria, N. H.; Muhammad, N.; Abdullah, M. M. A. B.

    2017-06-01

    In recent years, the development of biodegradable materials from renewable sources based on polymeric biomaterials have grown rapidly due to increase environmental concerns and the shortage of petroleum sources. In this regard, naturally renewable polymers such as starch has shown great potential as environmental friendly materials. Besides, the unique properties of starch such as biodegradable and non-toxic, biocompatible and solubility make them useful for a various biomedical applications. Regardless of their unique properties, starch materials are known to have limitations in term of poor processability, low mechanical properties, poor long term stability and high water sensitivity. In order to overcome these limitations, the incorporation of nano size fillers into starch materials (nanocomposites) has been introduced. This review aims to give an overview about structure and characteristics of starch, modification of starch by nanocomposites and their potential for biomedical applications.

  11. Characterization of organobentonite used for polymer nanocomposites

    International Nuclear Information System (INIS)

    Lee, J.Y.; Lee, H.K.

    2004-01-01

    Montmorillonite-rich clay was fractionated from bentonite mined from Kampo area in Korea, and it was treated with many cationic organo-surfactant. The chemical and physical characteristics of them are investigated, and epoxy nanocomposites were also studied. To calculate the exchanged content of organo-surfactant, thermogravimetric was carried out and interlayer distance was measured by wide-angle X-ray diffractometer. The interlayer distance for MMT-III, HDA-M, ODA-M, CTMA-M, and ODTMA-M were 1.21, 1.53, 1.57, 2.04, and 2.07 nm. All organobentonites were delaminated in the epoxy matrix forming the epoxy/organobentonite nanocomposites with various contents. Tensile strength and Young's modulus were modified by loading the organobentonite

  12. Mullins' effect in polymer/clay nanocomposites

    DEFF Research Database (Denmark)

    Drozdov, Aleksey; Christiansen, Jesper de Claville; Klitkou, Rasmus

    2012-01-01

    of memory of deformation history: when two samples are subjected to loading programs that differ along the first n ¡ 1 cycles and coincide afterwards, their stress– strain diagrams coincide starting from the nth cycle. Constitutive equations are developed in cyclic viscoelasticity and viscoplasticity...... of nanocomposites, and adjustable parameters in the stress–strain relations are found by fitting the experimental data. Ability of the model to predict the fading memory phenomenon is confirmed by numerical simulation.......Abstract. Experimental data are reported on polypropylene/clay nanocomposites in uniaxial cyclic tensile tests at room temperature (oscillations between maximum strains and the zero minimum stress with maximum strains increasing monotonically with number of cycles). Observations reveal fading...

  13. Polypyrrole-silver Nanocomposite: Synthesis and Characterization

    OpenAIRE

    D. M. Nerkar; S. V. Panse; S. P. Patil; S. E. Jaware; G. G. Padhye

    2016-01-01

    Polypyrrole-Silver (PPy-Ag) nanocomposite has been successfully synthesized by the chemical oxidative polymerization of pyrrole with iron (III) chloride as an oxidant, in the presence of a colloidal suspension of silver nanoparticles. Turkevich method (Citrate reduction method) was used for the synthesis of silver nanoparticles (Ag NPs). The silver nanoparticles were characterized by UV-Visible spectroscopy which showed an absorption band at 423 nm confirming the formation of nanoparticles. P...

  14. Green synthesis of graphene/Ag nanocomposites

    International Nuclear Information System (INIS)

    Yuan Wenhui; Gu Yejian; Li Li

    2012-01-01

    Graphical abstract: A facile and green approach to synthesis of GNS/AgNPs is reported by employing sodium citrate as reductant, and this study represents the use of biocompounds for nontoxic and scalable production of GNS/AgNPs under a suitable concentration of silver ions and the prepared GNS/AgNPs can be used in the field of disinfection. Highlights: ► Graphene/Ag nanocomposites were prepared by a green and facile strategy based on sodium citrate. ► The influence of AgNO 3 amount on particle size and size range of AgNPs was studied. ► The surface plasmon resonance properties of AgNPs on graphene was investigated. ► The antibacterial activity of silver nanoparticles was retained in the nanocomposites. - Abstract: Graphene/Ag nanocomposites (GNS/AgNPs) were fabricated via a green and facile method, employing graphite oxide (GO) as a precursor of graphene, AgNO 3 as a precursor of Ag nanoparticles, and sodium citrate as an environmentally friendly reducing and stabilizing agent. The synthesized GNS/AgNPs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and Raman spectra (RS), respectively. The results indicated that graphite oxide was completely reduced to graphene, and the silver ion was reduced by sodium citrate simultaneously. Under a suitable dosage of silver ions, well-dispersed AgNPs on the graphene sheets mostly centralized at 20–25 nm. The surface plasmon resonance property of AgNPs on graphene showed that there was a interaction between AgNPs and graphene supports. In addition, antibacterial activity of silver nanoparticles was retained in the nanocomposites, suggesting that they can be potentially used as a graphene-based biomaterial.

  15. Graphitic carbon nitride based nanocomposites: a review

    Science.gov (United States)

    Zhao, Zaiwang; Sun, Yanjuan; Dong, Fan

    2014-11-01

    Graphitic carbon nitride (g-C3N4), as an intriguing earth-abundant visible light photocatalyst, possesses a unique two-dimensional structure, excellent chemical stability and tunable electronic structure. Pure g-C3N4 suffers from rapid recombination of photo-generated electron-hole pairs resulting in low photocatalytic activity. Because of the unique electronic structure, the g-C3N4 could act as an eminent candidate for coupling with various functional materials to enhance the performance. According to the discrepancies in the photocatalytic mechanism and process, six primary systems of g-C3N4-based nanocomposites can be classified and summarized: namely, the g-C3N4 based metal-free heterojunction, the g-C3N4/single metal oxide (metal sulfide) heterojunction, g-C3N4/composite oxide, the g-C3N4/halide heterojunction, g-C3N4/noble metal heterostructures, and the g-C3N4 based complex system. Apart from the depiction of the fabrication methods, heterojunction structure and multifunctional application of the g-C3N4-based nanocomposites, we emphasize and elaborate on the underlying mechanisms in the photocatalytic activity enhancement of g-C3N4-based nanocomposites. The unique functions of the p-n junction (semiconductor/semiconductor heterostructures), the Schottky junction (metal/semiconductor heterostructures), the surface plasmon resonance (SPR) effect, photosensitization, superconductivity, etc. are utilized in the photocatalytic processes. Furthermore, the enhanced performance of g-C3N4-based nanocomposites has been widely employed in environmental and energetic applications such as photocatalytic degradation of pollutants, photocatalytic hydrogen generation, carbon dioxide reduction, disinfection, and supercapacitors. This critical review ends with a summary and some perspectives on the challenges and new directions in exploring g-C3N4-based advanced nanomaterials.

  16. Reactive Nanocomposites for Controllable Adhesive Debonding

    Science.gov (United States)

    2011-08-01

    technologies include shape memory alloy (SMA)-based approach, a chemical foaming agent (CFA) approach, and a reactive nanocomposite (RNC) approach. SMA...anofoil (a) Component 1 Thermoset Adhesive Component 2 Nano-coating (b) Figure 2. Debonding approach where (a) freestanding...J. Controlled Adhesive Debonding of RAH-66 Comanche Chines Using Shape Memory Alloys ; ARL-TR-2937; U.S. Army Research Laboratory: Aberdeen Proving

  17. Asphaltenes-based polymer nano-composites

    Science.gov (United States)

    Bowen, III, Daniel E

    2013-12-17

    Inventive composite materials are provided. The composite is preferably a nano-composite, and comprises an asphaltene, or a mixture of asphaltenes, blended with a polymer. The polymer can be any polymer in need of altered properties, including those selected from the group consisting of epoxies, acrylics, urethanes, silicones, cyanoacrylates, vulcanized rubber, phenol-formaldehyde, melamine-formaldehyde, urea-formaldehyde, imides, esters, cyanate esters, allyl resins.

  18. Maghemite polymer nanocomposites with modulated magnetic properties

    International Nuclear Information System (INIS)

    Millan, A.; Palacio, F.; Falqui, A.; Snoeck, E.; Serin, V.; Bhattacharjee, A.; Ksenofontov, V.; Guetlich, P.; Gilbert, I.

    2007-01-01

    A method is presented for the production of maghemite polymer nanocomposites with modulated magnetic properties. Magnetic nanocomposites prepared using this method show regular variation in the magnetic blocking temperature from 2 K to 300 K, and variation in the saturation magnetization from 0 to 50 emu g -1 (Fe 2 O 3 ). The method is based on the in situ formation of maghemite nanoparticles in nitrogen-base polymer matrixes. The particle size can be varied regularly from 1.5 nm to 16 nm by changing the ratio of iron loading in the polymer and/or the Fe(II)/Fe(III) ratios. The particles are isolated and uniformly distributed within the matrix. The materials were characterized by electron microscopy, electron energy loss spectroscopy, Moessbauer spectroscopy, infrared spectroscopy, small angle X-ray scattering, wide angle X-ray scattering and magnetic measurements. The nanocomposites obtained are useful model material for the study of the magnetic behavior of magnetic nanoparticles, as well as for use in many industrial and biomedical applications

  19. Polymer nanocomposites: polymer and particle dynamics

    KAUST Repository

    Kim, Daniel

    2012-01-01

    Polymer nanocomposites containing nanoparticles smaller than the random coil size of their host polymer chains are known to exhibit unique properties, such as lower viscosity and glass transition temperature relative to the neat polymer melt. It has been hypothesized that these unusual properties result from fast diffusion of the nanostructures in the host polymer, which facilitates polymer chain relaxation by constraint release and other processes. In this study, the effects of addition of sterically stabilized inorganic nanoparticles to entangled cis-1,4-polyisoprene and polydimethylsiloxane on the overall rheology of nanocomposites are discussed. In addition, insights about the relaxation of the host polymer chains and transport properties of nanoparticles in entangled polymer nanocomposites are presented. The nanoparticles are found to act as effective plasticizers for their entangled linear hosts, and below a critical, chemistry and molecular-weight dependent particle volume fraction, lead to reduced viscosity, glass transition temperature, number of entanglements, and polymer relaxation time. We also find that the particle motions in the polymer host are hyperdiffusive and at the nanoparticle length scale, the polymer host acts like a simple, ideal fluid and the composites\\' viscosity rises with increasing particle concentration. © 2012 The Royal Society of Chemistry.

  20. Magnetic polymer nanocomposites for sensing applications

    KAUST Repository

    Alfadhel, Ahmed

    2014-11-01

    We report the fabrication and characterization of magnetic polymer nanocomposites for a wide range of sensing applications. The composites are made of magnetic nanowires (NWs) incorporated into polymers such as polydimethylsiloxane (PDMS) or UV sensitive SU-S. The developed composites utilize the permanent magnetic behavior of the NWs, allowing remote operation without an additional magnetic field to magnetize the NWs, which simplifies miniaturization and integration in microsystems. In addition, the nanocomposite benefits from the easy patterning of the polymer leading to a corrosion resistant, highly elastic, and permanent magnetic material that can be used to develop highly sensitive systems. Nanocomposite pillars are realized and integrated on magnetic sensor elements to achieve highly sensitive and power efficient flow and tactile sensors. The developed flow sensor can detect air and water flow at a power consumption as little as SO nW and a resolution up to 15 μm/s with easily modifiable performance. A tactile sensor element prototype is realized using the same concept, where a pressure range of 0-169 kPa is detected with a resolution of up to 1.3 kPa. © 2014 IEEE.

  1. Synthesis of poly(furfuryl alcohol)/montmorillonite nanocomposites ...

    Indian Academy of Sciences (India)

    The purpose of this study was to obtain poly(furfuryl alcohol) nanocomposites with Algerian organically modified clay (termed 12-montmorillonite). The formation of poly(furfuryl alcohol) was confirmed by infrared spectroscopy (IR); the prepared nanocomposites were characterized by X-ray diffraction (XRD), transmission ...

  2. Strengthening of Aluminum Wires Treated with A206/Alumina Nanocomposites

    Directory of Open Access Journals (Sweden)

    David Florián-Algarín

    2018-03-01

    Full Text Available This study sought to characterize aluminum nanocomposite wires that were fabricated through a cold-rolling process, having potential applications in TIG (tungsten inert gas welding of aluminum. A206 (Al-4.5Cu-0.25Mg master nanocomposites with 5 wt % γAl2O3 nanoparticles were first manufactured through a hybrid process combining semi-solid mixing and ultrasonic processing. A206/1 wt % γAl2O3 nanocomposites were fabricated by diluting the prepared master nanocomposites with a monolithic A206 alloy, which was then added to a pure aluminum melt. The fabricated Al–γAl2O3 nanocomposite billet was cold-rolled to produce an Al nanocomposite wire with a 1 mm diameter and a transverse area reduction of 96%. Containing different levels of nanocomposites, the fabricated samples were mechanically and electrically characterized. The results demonstrate a significantly higher strength of the aluminum wires with the nanocomposite addition. Further, the addition of alumina nanoparticles affected the wires’ electrical conductivity compared with that of pure aluminum and aluminum–copper alloys. The overall properties of the new material demonstrate that these wires could be an appealing alternative for fillers intended for aluminum welding.

  3. Ultrasound assisted synthesis of PMMA/clay nanocomposites: Study ...

    Indian Academy of Sciences (India)

    The Young's modulus, breaking stress, elongation at break, toughness, yield stress and yield strain of the nanocomposites as a function of different clay concentrations and ultrasonic power were measured. Particle diameter of the nanocomposites was measured by laser diffraction technique. Oxygen permeability of the ...

  4. Polyaniline-CuO hybrid nanocomposite with enhanced electrical conductivity

    Science.gov (United States)

    de Souza, Vânia S.; da Frota, Hidembergue O.; Sanches, Edgar A.

    2018-02-01

    A hybrid nanocomposite based on a polymer matrix constituted of Polyaniline Emeraldine-salt form (PANI-ES) reinforced by copper oxide II (CuO) particles was obtained by in situ polymerization. Structural, morphological and electrical properties of the pure materials and nanocomposite form were investigated. The presence of CuO particles in the nanocomposite material affected the natural alignment of the polymer chains. XRD technique allowed the visualization of the polymer amorphization in the nanocomposite form, suggesting an interaction between both phases. The FTIR spectra confirmed this molecular interaction due to the blue shift of the characteristic absorption peaks of PANI-ES in the nanocomposite form. SEM images revealed that the polymer nanofiber morphology was no longer observed in the nanocomposite. The CuO spherical particles are randomly dispersed in the polymer matrix. The density functional theory plus the Coulomb interaction method revealed a charge transfer from PANI to CuO slab. Moreover, the density of states (DOS) has revealed that the nanocomposite behaves as a metal. In agreement, the electrical conductivity showed an increase of 60% in the nanocomposite material.

  5. Cellulose nanocrystal: electronically conducting polymer nanocomposites for supercapacitors

    OpenAIRE

    Liew, Soon Yee

    2012-01-01

    This thesis describes the use of cellulose nanocrystals for the fabrication of porous nanocomposites with electronic conducting polymers for electrochemical supercapacitor applications. The exceptional strength and negatively charged surface functionalities on cellulose nanocrystals are utilised in these nanocomposites. The negatively charged surface functionalities on cellulose nanocrystals allow their simultaneous incorporation into electropolymerised, positively charged conducting polymer ...

  6. Synthesis and Investigation of Carbon-Based Nanocomposites for Supercapacitors

    OpenAIRE

    LI WAN

    2018-01-01

    Carbon-based nanocomposites were synthesized for high-performance supercapacitors. The coalition between each of the constituent in the nanocomposites and the performance was investigated. Continuous efforts have been put to improve the supercapacitor assembly techniques from conventional supercapacitor to all-solid-state supercapacitor and to binder-free supercapacitor.

  7. Characterization of PAN/ATO nanocomposites prepared by solution ...

    Indian Academy of Sciences (India)

    Conducting nanocomposites of polyacrylonitrile (PAN) and antimony-doped tin oxide (ATO) were prepared by solution blending. Electrical properties of the nanocomposites were characterized by means of electrical conductivity measurements and the phase structures were investigated via scanning electron microscopy ...

  8. Synthesis and characterization of nanocomposites based on poly(3 ...

    Indian Academy of Sciences (India)

    The structure and morphologies of LNMO/P3HT- g -CNTs nanocomposites have also been performed by SEM, XRD and TEM. The electrochemical performance of LNMO/P3HT- g -CNTs nanocomposites as cathode materials of lithium-ion batteries were investigated by cyclic voltammetry and electrochemical impedance ...

  9. Environmental and Cost Assessment of a Polypropylene Nanocomposite

    NARCIS (Netherlands)

    Roes, A.L.|info:eu-repo/dai/nl/303022388; Marsili, E.; Nieuwlaar, E.|info:eu-repo/dai/nl/073931373; Patel, M.K.|info:eu-repo/dai/nl/18988097X

    2007-01-01

    This paper describes a study on the use of a polypropylene (PP)/layered silicate nanocomposite as packaging film, agricultural film, and automotive panels. The study’s main question was “Are the environmental impacts and costs throughout the life cycle of nanocomposite products lower than those of

  10. Strengthening of Aluminum Wires Treated with A206/Alumina Nanocomposites.

    Science.gov (United States)

    Florián-Algarín, David; Marrero, Raúl; Li, Xiaochun; Choi, Hongseok; Suárez, Oscar Marcelo

    2018-03-10

    This study sought to characterize aluminum nanocomposite wires that were fabricated through a cold-rolling process, having potential applications in TIG (tungsten inert gas) welding of aluminum. A206 (Al-4.5Cu-0.25Mg) master nanocomposites with 5 wt % γAl₂O₃ nanoparticles were first manufactured through a hybrid process combining semi-solid mixing and ultrasonic processing. A206/1 wt % γAl₂O₃ nanocomposites were fabricated by diluting the prepared master nanocomposites with a monolithic A206 alloy, which was then added to a pure aluminum melt. The fabricated Al-γAl₂O₃ nanocomposite billet was cold-rolled to produce an Al nanocomposite wire with a 1 mm diameter and a transverse area reduction of 96%. Containing different levels of nanocomposites, the fabricated samples were mechanically and electrically characterized. The results demonstrate a significantly higher strength of the aluminum wires with the nanocomposite addition. Further, the addition of alumina nanoparticles affected the wires' electrical conductivity compared with that of pure aluminum and aluminum-copper alloys. The overall properties of the new material demonstrate that these wires could be an appealing alternative for fillers intended for aluminum welding.

  11. Ecoefficiency indicators for development of nano-composites

    DEFF Research Database (Denmark)

    Olsen, Stig Irving; Laurent, Alexis

    nanocomposites (5 wt%-nanofiller) were investigated; PU/CNT (in-situ polymerization), PP/CNT (in-situ polymerization), PU/clay (bulk polymerization), and PP/clay nanocomposites (bulk polymerization). Due to of lack of information, only the material stages (extraction of materials) and the production...

  12. Cyclic viscoelasticity and viscoplasticity of polypropylene/clay nanocomposites

    DEFF Research Database (Denmark)

    Drozdov, Aleksey; Christiansen, Jesper de Claville; Hog Lejre, Anne-Lise

    2012-01-01

    Observations are reported in tensile relaxation tests under stretching and retraction on poly-propylene/clay nanocomposites with various contents of filler. A two-phase constitutive model is developed in cyclic viscoelasticity and viscoplasticity of hybrid nanocomposites. Adjustable parameters in...

  13. Carbon-Nickel oxide nanocomposites: Preparation and charecterisation

    CSIR Research Space (South Africa)

    Tile, N

    2011-07-01

    Full Text Available Nanocomposite materials have wide range of applications in solar energy conversion. In this work, C-NiO nanocomposite coatings are prepared using sol-gel synthesis and deposited on aluminium substrates using a spin coater. The coatings are prepared...

  14. A biodegradable polymer nanocomposite: Mechanical and barrier properties

    Science.gov (United States)

    Lilichenko, N.; Maksimov, R. D.; Zicans, J.; Merijs Meri, R.; Plume, E.

    2008-01-01

    The preparation of an environmentally friendly nanocomposite based on plasticized potato starch and unmodified montmorillonite clay is described. Data on the influence of montmorillonite concentration on the mechanical properties of the materials obtained are reported. The effective elastic constants of the nanocomposites are calculated. The calculation results are compared with experimental data. The influence of montmorillonite content on the moisture permeability is also investigated.

  15. Modifying Silicates for Better Dispersion in Nanocomposites

    Science.gov (United States)

    Campbell, Sandi

    2005-01-01

    An improved chemical modification has been developed to enhance the dispersion of layered silicate particles in the formulation of a polymer/silicate nanocomposite material. The modification involves, among other things, the co-exchange of an alkyl ammonium ion and a monoprotonated diamine with interlayer cations of the silicate. The net overall effects of the improved chemical modification are to improve processability of the nanocomposite and maximize the benefits of dispersing the silicate particles into the polymer. Some background discussion is necessary to give meaning to a description of this development. Polymer/silicate nanocomposites are also denoted polymer/clay composites because the silicate particles in them are typically derived from clay particles. Particles of clay comprise layers of silicate platelets separated by gaps called "galleries." The platelet thickness is 1 nm. The length varies from 30 nm to 1 m, depending on the silicate. In order to fully realize the benefits of polymer/silicate nanocomposites, it is necessary to ensure that the platelets become dispersed in the polymer matrices. Proper dispersion can impart physical and chemical properties that make nanocomposites attractive for a variety of applications. In order to achieve nanometer-level dispersion of a layered silicate into a polymer matrix, it is typically necessary to modify the interlayer silicate surfaces by attaching organic functional groups. This modification can be achieved easily by ion exchange between the interlayer metal cations found naturally in the silicate and protonated organic cations - typically protonated amines. Long-chain alkyl ammonium ions are commonly chosen as the ion-exchange materials because they effectively lower the surface energies of the silicates and ease the incorporation of organic monomers or polymers into the silicate galleries. This completes the background discussion. In the present improved modification of the interlayer silicate surfaces

  16. Wellbore Seal Repair Using Nanocomposite Materials

    Energy Technology Data Exchange (ETDEWEB)

    Stormont, John [Univ. of New Mexico, Albuquerque, NM (United States)

    2016-08-31

    Nanocomposite wellbore repair materials have been developed, tested, and modeled through an integrated program of laboratory testing and numerical modeling. Numerous polymer-cement nanocomposites were synthesized as candidate wellbore repair materials using various combinations of base polymers and nanoparticles. Based on tests of bond strength to steel and cement, ductility, stability, flowability, and penetrability in opening of 50 microns and less, we identified Novolac epoxy reinforced with multi-walled carbon nanotubes and/or alumina nanoparticles to be a superior wellbore seal material compared to conventional microfine cements. A system was developed for testing damaged and repaired wellbore specimens comprised of a cement sheath cast on a steel casing. The system allows independent application of confining pressures and casing pressures while gas flow is measured through the specimens along the wellbore axis. Repair with the nanocomposite epoxy base material was successful in dramatically reducing the flow through flaws of various sizes and types, and restoring the specimen comparable to an intact condition. In contrast, repair of damaged specimens with microfine cement was less effective, and the repair degraded with application of stress. Post-test observations confirm the complete penetration and sealing of flaws using the nanocomposite epoxy base material. A number of modeling efforts have supported the material development and testing efforts. We have modeled the steel-repair material interface behavior in detail during slant shear tests, which we used to characterize bond strength of candidate repair materials. A numerical model of the laboratory testing of damaged wellbore specimens was developed. This investigation found that microannulus permeability can satisfactorily be described by a joint model. Finally, a wellbore model has been developed that can be used to evaluate the response of the wellbore system (casing, cement, and microannulus

  17. Separation performance and interfacial properties of nanocomposite reverse osmosis membranes

    KAUST Repository

    Pendergast, MaryTheresa M.; Ghosh, Asim K.; Hoek, E.M.V.

    2013-01-01

    Four different types of nanocomposite reverse osmosis (RO) membranes were formed by interfacial polymerization of either polyamide (PA) or zeolite A-polyamide nanocomposite (ZA-PA) thin films over either pure polysulfone (PSf) or zeolite A-polysulfone nanocomposite (ZA-PSf) support membranes cast by wet phase inversion. All three nanocomposite membranes exhibited superior separation performance and interfacial properties relative to hand-cast TFC analogs including: (1) smoother, more hydrophilic surfaces (2) higher water permeability and salt rejection, and (3) improved resistance to physical compaction. Less compaction occurred for membranes with nanoparticles embedded in interfacially polymerized coating films, which adds further proof that flux decline associated with physical compaction is influenced by coating film properties in addition to support membrane properties. The new classes of nanocomposite membrane materials continue to offer promise of further improved RO membranes for use in desalination and advanced water purification. © 2011 Elsevier B.V.

  18. Scattering, absorption and transmittance of experimental graphene dental nanocomposites

    Science.gov (United States)

    Pérez, María. M.; Salas, Marianne; Moldovan, Marionara; Dudea, Diana; Yebra, Ana; Ghinea, Razvan

    2017-08-01

    Optical properties of experimental graphene dental nanocomposites were studied. Spectral reflectance was measured and S and K coefficients as well as transmittance of samples were calculated using Kubelka-Munk's equations. The spectral behavior of S, K and T experimental graphene exhibited different trends compared with the commercial nanocomposites and they were statistically different. Experimental nanocomposites show higher scattering and lower transmittance when compared with commercial nanocomposite, probably, due to the shape, type and size of the filler. K for short wavelength of the pre-polymerized experimental nancomposites was very low. According to our results, hidroxypatite with graphene oxide used in dental nanocomposites needs to be improved to reproduce esthetic properties of natural dental tissues and to have potentially clinical applications.

  19. Synthesis and Characterization of Hydroxyapatite/Fullerenol Nanocomposites.

    Science.gov (United States)

    Djordjevic, Aleksandar; Ignjatovic, Nenad; Seke, Mariana; Jovic, Danica; Uskokovic, Dragan; Rakocevic, Zlatko

    2015-02-01

    Fullerenols are polyhydroxylated, water soluble derivatives of fullerene C60, with potential application in medicine as diagnostic agents, antioxidants or nano drug carriers. This paper describes synthesis and physical characterization of a new nanocomposite hydroxyapatite/fullerenol. Surface of the nanocomposite hydroxyapatite/fullerenol is inhomogeneous with the diameter of the particles in the range from 100 nm to 350 nm. The ζ potential of this nanocomposite is ten times lower when compared to hydroxyapatite. Surface phosphate groups of hydroxyapatite are prone to forming hydrogen bonds, when in close contact with hydroxyl groups, which could lead to formation of hydrogen bonds between hydroxyapatite and hydroxyl groups of fullerenol. The surface of hydroxyapatite particles (-2.5 mV) was modified by fullerenol particles, as confirmed by the obtained ζ potential value of the nanocomposite biomaterial hydroxyapatite/fullerenol (-25.0 mV). Keywords: Hydroxyapatite, Fullerenol, Nanocomposite, Surface Analysis.

  20. Methanol sensing characteristics of conducting polypyrrole-silver nanocomposites

    Science.gov (United States)

    Kabir, L.; Mandal, S. K.

    2012-05-01

    Methanol sensing characteristics of conducting polypyrrole-silver nanocomposites are reported here. The nanocomposites are synthesized by wet chemical technique with different amount of silver loadings (5-15 mol%). The sensitivity of the nanocomposites upon exposure to gas molecules is critically dependent on the silver loadings and the concentration of the exposed gas. This is possibly instigated by the modified metal-polymer interface and the polar nature of the constituent metal and the exposed gas. Interaction of the alcohol gas with the polypyrrole chains in the presence of silver effectively determines the change in resistance and hence the sensitivity of the nanocomposites upon exposure to methanol. The adsorption of methanol molecules within the nanocomposites and the subsequent chemical reactions are studied by Fourier transform infrared (FTIR) spectroscopy.

  1. Electrospun nanocomposite fibrous polymer electrolyte for secondary lithium battery applications

    International Nuclear Information System (INIS)

    Padmaraj, O.; Rao, B. Nageswara; Jena, Paramananda; Satyanarayana, N.; Venkateswarlu, M.

    2014-01-01

    Hybrid nanocomposite [poly(vinylidene fluoride -co- hexafluoropropylene) (PVdF-co-HFP)/magnesium aluminate (MgAl 2 O 4 )] fibrous polymer membranes were prepared by electrospinning method. The prepared pure and nanocomposite fibrous polymer electrolyte membranes were soaked into the liquid electrolyte 1M LiPF 6 in EC: DEC (1:1,v/v). XRD and SEM are used to study the structural and morphological studies of nanocomposite electrospun fibrous polymer membranes. The nanocomposite fibrous polymer electrolyte membrane with 5 wt.% of MgAl 2 O 4 exhibits high ionic conductivity of 2.80 × 10 −3 S/cm at room temperature. The charge-discharge capacity of Li/LiCoO 2 coin cells composed of the newly prepared nanocomposite [(16 wt.%) PVdF-co-HFP+(5 wt.%) MgAl 2 O 4 ] fibrous polymer electrolyte membrane was also studied and compared with commercial Celgard separator

  2. Generalized Effective Medium Theory for Particulate Nanocomposite Materials

    Directory of Open Access Journals (Sweden)

    Muhammad Usama Siddiqui

    2016-08-01

    Full Text Available The thermal conductivity of particulate nanocomposites is strongly dependent on the size, shape, orientation and dispersion uniformity of the inclusions. To correctly estimate the effective thermal conductivity of the nanocomposite, all these factors should be included in the prediction model. In this paper, the formulation of a generalized effective medium theory for the determination of the effective thermal conductivity of particulate nanocomposites with multiple inclusions is presented. The formulated methodology takes into account all the factors mentioned above and can be used to model nanocomposites with multiple inclusions that are randomly oriented or aligned in a particular direction. The effect of inclusion dispersion non-uniformity is modeled using a two-scale approach. The applications of the formulated effective medium theory are demonstrated using previously published experimental and numerical results for several particulate nanocomposites.

  3. Manufacturing of Nanocomposite Carbon Fibers and Composite Cylinders

    Science.gov (United States)

    Tan, Seng; Zhou, Jian-guo

    2013-01-01

    Pitch-based nanocomposite carbon fibers were prepared with various percentages of carbon nanofibers (CNFs), and the fibers were used for manufacturing composite structures. Experimental results show that these nanocomposite carbon fibers exhibit improved structural and electrical conductivity properties as compared to unreinforced carbon fibers. Composite panels fabricated from these nanocomposite carbon fibers and an epoxy system also show the same properties transformed from the fibers. Single-fiber testing per ASTM C1557 standard indicates that the nanocomposite carbon fiber has a tensile modulus of 110% higher, and a tensile strength 17.7% times higher, than the conventional carbon fiber manufactured from pitch. Also, the electrical resistance of the carbon fiber carbonized at 900 C was reduced from 4.8 to 2.2 ohm/cm. The manufacturing of the nanocomposite carbon fiber was based on an extrusion, non-solvent process. The precursor fibers were then carbonized and graphitized. The resultant fibers are continuous.

  4. Eco-friendly polymer nanocomposites processing and properties

    CERN Document Server

    Thakur, Vijay Kumar

    2015-01-01

    This book contains precisely referenced chapters, emphasizing environment-friendly polymer nanocomposites with basic fundamentals, practicality and alternatives to traditional nanocomposites through detailed reviews of different environmental friendly materials procured from different resources, their synthesis and applications using alternative green approaches. The book aims at explaining basics of eco-friendly polymer nanocomposites from different natural resources and their chemistry along with practical applications which present a future direction in the biomedical, pharmaceutical and automotive industry. The book attempts to present emerging economic and environmentally friendly polymer nanocomposites that are free from side effects studied in the traditional nanocomposites. This book is the outcome of contributions by many experts in the field from different disciplines, with various backgrounds and expertises. This book will appeal to researchers as well as students from different disciplines. The co...

  5. Effect of Nanocomposite Structures on Fracture Behavior of Epoxy-Clay Nanocomposites Prepared by Different Dispersion Methods

    Directory of Open Access Journals (Sweden)

    Mohammad Bashar

    2014-01-01

    Full Text Available The effects of organic modifier and processing method on morphology and mechanical properties of epoxy-clay nanocomposites were investigated. In this study, the preparation of nanocomposites by exfoliation-adsorption method involved an ultrasonic mixing procedure, and mechanical blending was used for in situ intercalative polymerization. The microstructure study revealed that the organoclay, which was ultrasonically mixed with the epoxy, partially exfoliated and intercalated. In contrast, organoclay remained in phase-separated and flocculated state after the mechanical blending process. Tensile stiffness increased significantly for the nanocomposite prepared by ultrasonic dispersion method through realizing the reinforcing potential of exfoliated silicate layers. Nanocomposites with exfoliated and intercalated nanoclay morphology were ineffective in enhancing the fracture toughness whereas nanocomposites with phase-separated and flocculated morphology have improved crack resistance predominantly by crack deflecting and pinning mechanisms.

  6. Evolution of structure and magnetic properties for BaFe{sub 11.9}Al{sub 0.1}O{sub 19} hexaferrite in a wide temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Trukhanov, A.V., E-mail: truhanov86@mail.ru [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); SSPA “Scientific and Practical Materials Research Centre of NAS of Belarus”, P. Brovki str., 19, 220072 Minsk, Belorussia (Belarus); Trukhanov, S.V. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); SSPA “Scientific and Practical Materials Research Centre of NAS of Belarus”, P. Brovki str., 19, 220072 Minsk, Belorussia (Belarus); Panina, L.V.; Kostishyn, V.G. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); Kazakevich, I.S. [SSPA “Scientific and Practical Materials Research Centre of NAS of Belarus”, P. Brovki str., 19, 220072 Minsk, Belorussia (Belarus); Trukhanov, An.V. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); SSPA “Scientific and Practical Materials Research Centre of NAS of Belarus”, P. Brovki str., 19, 220072 Minsk, Belorussia (Belarus); Trukhanova, E.L.; Natarov, V.O. [SSPA “Scientific and Practical Materials Research Centre of NAS of Belarus”, P. Brovki str., 19, 220072 Minsk, Belorussia (Belarus); Turchenko, V.A. [Joint Institute for Nuclear Research, Joliot-Curie Str., 6, 141980 Dubna (Russian Federation); Donetsk Institute of Physics and Technology named after A.A. Galkin of the NAS of Ukraine, 72 R.Luxemburg Str., 83114 Donetsk (Ukraine); Salem, M.M. [National University of Science and Technology MISiS, Leninsky Prospekt, 4, 119049 Moscow (Russian Federation); and others

    2017-03-15

    M-type BaFe{sub 11.9}Al{sub 0.1}O{sub 19} hexaferrite was successfully synthesized by solid state reactions. Precision investigations of crystal and magnetic structures of BaFe{sub 11.9}Al{sub 0.1}O{sub 19} powder by neutron diffraction in the temperature range 4.2–730 K have been performed. Magnetic and electrical properties investigations were carried out in the wide temperature range. Neutron powder diffraction data were successfully refined in approximation for both space groups (SG): centrosymmetric #194 (standard non-polar phase) and non-centrosymmetric #186 (polar phase). It has been shown that at low temperatures (below room temperature) better fitting results (value χ{sup 2}) were for the polar phase (SG: #186) or for the two phases coexistence (SG: #186 and SG: #194). At high temperatures (400–730 K) better fitting results were for SG: #194. It was established coexistence of the dual ferroic properties (specific magnetization and spontaneous polarization) at room temperature. Strong correlation between magnetic and electrical subsystems was demonstrated (magnetoelectrical effect). Temperature dependences of the spontaneous polarization, specific magnetization and magnetoelectrical effect were investigated.

  7. Magnetic and microwave absorption properties of rare earth ions (Sm{sup 3+}, Er{sup 3+}) doped strontium ferrite and its nanocomposites with polypyrrole

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Juhua, E-mail: luojuhua@163.com [School of Materials Engineering, Yancheng Institute of Technology, Yancheng 224051 (China); Xu, Yang; Mao, Hongkai [School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013 (China)

    2015-05-01

    M-type strontium ferrite substituted by RE (RE=Sm{sup 3+}, Er{sup 3+}) were prepared via a sol–gel method. Polypyrrole (PPy)/ferrite nanocomposites (with 20 wt% ferrite) were prepared by in situ polymerization method in the presence of ammonium persulfate. Effect of the substituted RE ions on structure, magnetic properties and microwave absorption properties were investigated by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and vector network analyzer. All XRD patterns show the single phase of strontium hexaferrite without other intermediate phases. The crystallite size of synthesized particle is within the range of 22.2–38.1 nm. The structural in character of the composites were investigated with FT-IR analysis. It shows that the ferrite successfully packed by PPy. TEM photographs show that the particle size had grown up to 50–100 nm after coating with PPy. In the magnetization for the PPy/SrSm{sub 0.3}Fe{sub 11.7}O{sub 19} (SrEr{sub 0.3}Fe{sub 11.7}O{sub 19}) composites, the coercivity (H{sub c}) of the composites both increased compared with the undoped composite while the saturation magnetization (M{sub s}) appeared opposite change with different RE ions. Considering the electromagnetic loss and impedance matching comprehensively, the Er-doped ferrite/PPy composite got the better microwave absorption performance with the maximum RL value of −24.01 dB in 13.8 GHz at 3.0 mm. And its width (<−10 dB) has reached 7.2 GHz which has covered the whole Ku band. - Highlights: • The influence of RE ions on the structure of PPy/SrRE{sub 0.3}Fe{sub 11.7}O{sub 19} is discussed. • The influence of RE ions on the magnetic properties of PPy/SrRE{sub 0.3}Fe{sub 11.7}O{sub 19} is discussed. • The influence of RE ions on electromagnetic losses of PPy/SrRE{sub 0.3}Fe{sub 11.7}O{sub 19} is discussed. • PPy/SrEr{sub 0.3}Fe{sub 11.7}O{sub 19} possessed the excellent absorption property.

  8. The Role of Nanofillers in Polymer Nanocomposites

    Science.gov (United States)

    Xu, Di

    Polymer nanocomposites have been widely used in many fields. By introducing nanoparticles as fillers, researchers are able to get reinforced materials and new materials with novel properties, such as stronger mechanics, enhanced optical properties and improved conductivity. Though experimental techniques have rapidly advanced to enable better control of materials at atomic level, there is still a lack of a fundamental understanding of the dynamics and structure-properties relations in polymer nanocomposites. In this thesis, we use computer simulations to study the molecular structure and connections between microstate to macro properties of a variety of nanocomposites. Our goal is to understand the role of nanofillers in complex nanocomposite systems and to assist nanocomposite design. Nanoplatelet fillers, such as clays, have shown superior effects on the properties of polymer gels. We used molecular dynamic simulation to study nanoplatelet-filled composite gel system, in which short-range attraction exists between the polymer and nanoplatelet fillers. We show that the polymers and nanoplatelet fillers formed organic-inorganic networks with nanoplatelets acting as crosslink junctions, and the network eventually percolates the system as fillers reached a critical concentration. Stress auto-correlation and step-strain test were applied to investigate the mechanical properties; the results show the simulated composites changed from fluid-like to solid-like. The mechanical changes were consistent with the percolation transition, and gelation mechanism was therefore believed to be similar to those pure polymer physical gels. It was observed platelets aggregated into a local intercalation structure, which significantly differs from typical spherical fillers. This unique intercalation structure was examined by radial distribution function and ordering parameters. We discussed how intercalation would affect the properties of the platelet composites by comparing them with

  9. Structural, magneto-optical properties and cation distribution of SrBi{sub x}La{sub x}Y{sub x}Fe{sub 12−3x}O{sub 19} (0.0 ≤ x ≤ 0.33) hexaferrites

    Energy Technology Data Exchange (ETDEWEB)

    Auwal, I.A. [Department of Chemistry, Fatih University, 34500 B. Çekmece, İstanbul (Turkey); Güngüneş, H. [Department of Physics, Hitit University, 19030 Çevre Yolu Bulvarı, Çorum (Turkey); Güner, S. [Department of Physics, Fatih University, 34500 B. Çekmece, İstanbul (Turkey); Shirsath, Sagar E. [Spin Device Technology Center, Faculty of Engineering, Shinshu University, 380-8553 Nagano (Japan); Sertkol, M. [Department of Physics Engineering, Istanbul Technical University, 34469 Maslak (Turkey); Baykal, A., E-mail: hbaykal@fatih.edu.tr [Department of Chemistry, Fatih University, 34500 B. Çekmece, İstanbul (Turkey)

    2016-08-15

    Highlights: • SrBi{sub x}La{sub x}Y{sub x}Fe{sub 12−3x}O{sub 19} (0.0 ≤ x ≤ 0.33) hexaferrites have been prepared by sol-gel autocombustion. • XRD patterns show that SrBi{sub x}La{sub x}Y{sub x}Fe{sub 12−3x}O{sub 19} (0.0 ≤ x ≤ 0.33) hexaferrites exhibit hexagonal structure. • The intrinsic coercivity (H{sub ci}) above 15000 Oe reveals that all samples are magnetically hard materials. - Abstract: SrBi{sub x}La{sub x}Y{sub x}Fe{sub 12−3x}O{sub 19} (0.0 ≤ x ≤ 0.33) hexaferrites were produced via sol-gel auto combustion. XRD patterns show that all the samples are single-phase M-type strontium hexaferrite (SrM). The magnetic hysteresis (σ-H) loops revealed the ferromagnetic nature of nanoparticles (NPs). The coercive field decreases from 4740 Oe to 2720 Oe with increasing ion content. In particular, SrBi{sub x}La{sub x}Y{sub x}Fe{sub 12−3x}O{sub 19} NPs with x = 0.0, 0.1, 0.2 have suitable magnetic characteristics (σ{sub s} = 62.03–64.72 emu/g and H{sub c} = 3105–4740 Oe) for magnetic recording. The intrinsic coercivity (H{sub ci}) above 15000 Oe reveals that all samples are magnetically hard materials. Tauc plots were used to specify the direct optical energy band gap (E{sub g}) of NPs. The E{sub g} values are between 1.76 eV and 1.85 eV. {sup 57}Fe Mössbauer spectroscopy data, the variation in line width, isomer shift, quadrupole splitting, relative area and hyperfine magnetic field values on Bi{sup 3+} La{sup 3+} and Y{sup 3+} substitutions have been determined.

  10. Gamma irradiation of melt processed biomedical PDLLA/HAP nanocomposites

    International Nuclear Information System (INIS)

    Dadbin, Susan; Kheirkhah, Yahya

    2014-01-01

    Poly(D-L lactide) PDLLA/hydroxyapatite (HAP) nanocomposites at various compositions were prepared by melt-compounding process and then subjected to gamma irradiation at a dose of 30 kGy. The morphology of the nanocomposites, characterized by transmission electron microscopy (TEM), displayed HAP nanoparticles at various sizes ranging from 10 to 100 nm distributed almost evenly within the polymer matrix. Differential scanning calorimetric (DSC) analysis of the irradiated nanocomposites showed an increase in the degree of crystallinity along with a melting peak split. The double melting peak suggested formation of different crystalline structures in the radiation exposed nanocomposites. Also the cold crystallization peak shifted to lower temperatures and became much sharper upon irradiation, indicating higher crystallization rate. The irradiated nanocomposites showed lower tensile strength and elongation at break, suggesting occurrence of some chain scission reactions in the PLA. - Highlights: • Biomedical polylactic acid/hydroxyapatite nanocomposites prepared by melt-compounding were gamma irradiated. • Transmission electron microscopy showed hydroxyapatite nanoparticles evenly distributed within polylactic acid ranging from 10 to 100 nm. • A halo appeared around hydroxyapatite particles showing interfacial interactions between polylactic acid and the particles. • Double melting peak appeared for polylactic acid in DSC thermograms upon gamma irradiation of the nanocomposites

  11. Modification of PMMA/graphite nanocomposites through ion beam technique

    Science.gov (United States)

    Singhal, Prachi; Rattan, Sunita; Avasthi, Devesh Kumar; Tripathi, Ambuj

    2013-08-01

    Swift heavy ion (SHI) irradiation is a special technique for inducing physical and chemical modifications in bulk materials. In the present work, the SHI hs been used to prepare nanocomposites with homogeneously dispersed nanoparticles. The nanographite was synthesized from graphite using the intercalation-exfoliation method. PMMA Poly(methyl methacrylate)/graphite nanocomposites have been synthesized by in situ polymerization. The prepared PMMA/graphite nanocomposite films were irradiated with SHI irradiation (Ni ion beam, 80 MeV and C ion beam, 50 MeV) at a fluence of 1×1010 to 3×1012 ions/cm2. The nanocomposite films were characterized by scanning electron microscope (SEM) and were evaluated for their electrical and sensor properties. After irradiation, significant changes in surface morphology of nanocomposites were observed as evident from the SEM images, which show the presence of well-distributed nanographite platelets. The irradiated nanocomposites exhibit better electrical and sensor properties for the detection of nitroaromatics with marked improvement in sensitivity as compared with unirradiated nanocomposites.

  12. Preparation and properties of biodegradable starch–clay nanocomposites

    KAUST Repository

    Chung, Yi-Lin

    2010-01-01

    Well-dispersed starch-clay nanocomposites were prepared by adding a dilute clay dispersion to a solution of starch followed by coprecipitation in ethanol. The clay didn\\'t significantly influence the type of crystalline structure of starch molecules although the amount of crystallinity appears to be somewhat lower in the nanocomposites. The nanocomposites show improved modulus and strength without a decrease in elongation at break. The increase in modulus and strength is 65% and 30%, respectively for the nanocomposite containing 5 wt.% clay compared to the unfilled starch materials. Further increases in clay result in deterioration in properties most likely due to poorer clay dispersion and lower polymer crystallinity. As the amount of water increases, the modulus of both pure starch and starch nanocomposites decreases, although the change is less pronounced in the nanocomposites suggesting that the addition of clay to form nanocomposites can improve the stability of starch-based products during transportation and storage. © 2009 Elsevier Ltd. All rights reserved.

  13. Vegetable Oil-Based Hyperbranched Thermosetting Polyurethane/Clay Nanocomposites

    Directory of Open Access Journals (Sweden)

    Deka Harekrishna

    2009-01-01

    Full Text Available Abstract The highly branched polyurethanes and vegetable oil-based polymer nanocomposites have been showing fruitful advantages across a spectrum of potential field of applications.Mesua ferreaL. seed oil-based hyperbranched polyurethane (HBPU/clay nanocomposites were prepared at different dose levels by in situ polymerization technique. The performances of epoxy-cured thermosetting nanocomposites are reported for the first time. The partially exfoliated structure of clay layers was confirmed by XRD and TEM. FTIR spectra indicate the presence of H bonding between nanoclay and the polymer matrix. The present investigation outlines the significant improvement of tensile strength, scratch hardness, thermostability, water vapor permeability, and adhesive strength without much influencing impact resistance, bending, and elongation at break of the nanocomposites compared to pristine HBPU thermoset. An increment of two times the tensile strength, 6 °C of melting point, and 111 °C of thermo-stability were achieved by the formation of nanocomposites. An excellent shape recovery of about 96–99% was observed for the nanocomposites. Thus, the formation of partially exfoliated clay/vegetable oil-based hyperbranched polyurethane nanocomposites significantly improved the performance.

  14. Vegetable Oil-Based Hyperbranched Thermosetting Polyurethane/Clay Nanocomposites.

    Science.gov (United States)

    Deka, Harekrishna; Karak, Niranjan

    2009-04-25

    The highly branched polyurethanes and vegetable oil-based polymer nanocomposites have been showing fruitful advantages across a spectrum of potential field of applications. Mesua ferrea L. seed oil-based hyperbranched polyurethane (HBPU)/clay nanocomposites were prepared at different dose levels by in situ polymerization technique. The performances of epoxy-cured thermosetting nanocomposites are reported for the first time. The partially exfoliated structure of clay layers was confirmed by XRD and TEM. FTIR spectra indicate the presence of H bonding between nanoclay and the polymer matrix. The present investigation outlines the significant improvement of tensile strength, scratch hardness, thermostability, water vapor permeability, and adhesive strength without much influencing impact resistance, bending, and elongation at break of the nanocomposites compared to pristine HBPU thermoset. An increment of two times the tensile strength, 6 degrees C of melting point, and 111 degrees C of thermo-stability were achieved by the formation of nanocomposites. An excellent shape recovery of about 96-99% was observed for the nanocomposites. Thus, the formation of partially exfoliated clay/vegetable oil-based hyperbranched polyurethane nanocomposites significantly improved the performance.

  15. Load transfer of nanocomposite film on aluminum substrate.

    Science.gov (United States)

    Her, Shiuh-Chuan; Chien, Pao-Chu

    2018-01-01

    Nanocomposite films have attracted much attention in recent years. Depending on the composition of the film and fabrication method, a large range of applications has been employed for nanocomposite films. In this study, nanocomposite films reinforced with multi-walled carbon nanotubes (MWCNTs) were deposited on the aluminum substrate through hot press processing. A shear lag model and Euler beam theory were employed to evaluate the stress distribution and load carrying capability of the nanocomposite film subjected to tensile load and bending moment. The influence of MWCNT on the Young's modulus and load carrying capability of the nanocomposite film was investigated through a parametric study. The theoretical predictions were verified by comparison with experimental tests. A close agreement with difference less than 6% was achieved between the theoretical prediction and experimental measurements. The Young's modulus and load transfer of the nanocomposite film reinforced with MWCNTs increases with the increase of the MWCNT loading. Compared to the neat epoxy film, nanocomposite film with 1 wt % of MWCNT exhibits an increase of 20% in both the Young's modulus and load carrying capability.

  16. Preparation and properties of biodegradable starch–clay nanocomposites

    KAUST Repository

    Chung, Yi-Lin; Ansari, Seema; Estevez, Luis; Hayrapetyan, Suren; Giannelis, Emmanuel P.; Lai, Hsi-Mei

    2010-01-01

    Well-dispersed starch-clay nanocomposites were prepared by adding a dilute clay dispersion to a solution of starch followed by coprecipitation in ethanol. The clay didn't significantly influence the type of crystalline structure of starch molecules although the amount of crystallinity appears to be somewhat lower in the nanocomposites. The nanocomposites show improved modulus and strength without a decrease in elongation at break. The increase in modulus and strength is 65% and 30%, respectively for the nanocomposite containing 5 wt.% clay compared to the unfilled starch materials. Further increases in clay result in deterioration in properties most likely due to poorer clay dispersion and lower polymer crystallinity. As the amount of water increases, the modulus of both pure starch and starch nanocomposites decreases, although the change is less pronounced in the nanocomposites suggesting that the addition of clay to form nanocomposites can improve the stability of starch-based products during transportation and storage. © 2009 Elsevier Ltd. All rights reserved.

  17. Single-walled carbon nanotubes nanocomposite microacoustic organic vapor sensors

    Energy Technology Data Exchange (ETDEWEB)

    Penza, M. [ENEA, Materials and New Technologies Unit, SS. 7, Appia, km 714, 72100 Brindisi (Italy)]. E-mail: michele.penza@brindisi.enea.it; Tagliente, M.A. [ENEA, Materials and New Technologies Unit, SS. 7, Appia, km 714, 72100 Brindisi (Italy); Aversa, P. [ENEA, Materials and New Technologies Unit, SS. 7, Appia, km 714, 72100 Brindisi (Italy); Cassano, G. [ENEA, Materials and New Technologies Unit, SS. 7, Appia, km 714, 72100 Brindisi (Italy); Capodieci, L. [ENEA, Materials and New Technologies Unit, SS. 7, Appia, km 714, 72100 Brindisi (Italy)

    2006-07-15

    We have developed highly sensitive microacoustic vapor sensors based on surface acoustic waves (SAWs) configured as oscillators using a two-port resonator 315, 433 and 915 MHz device. A nanocomposite film of single-walled carbon nanotubes (SWCNTs) embedded in a cadmium arachidate (CdA) amphiphilic organic matrix was prepared by Langmuir-Blodgett technique with a different SWCNTs weight filler content onto SAW transducers as nanosensing interface for vapor detection, at room temperature. The structural properties and surface morphology of the nanocomposite have been examined by X-ray diffraction, transmission and scanning electron microscopy, respectively. The sensing properties of SWCNTs nanocomposite LB films consisting of tangled nanotubules have been also investigated by using Quartz Crystal Microbalance 10 MHz AT-cut quartz resonators. The measured acoustic sensing characteristics indicate that the room-temperature SAW sensitivity to polar and nonpolar tested organic molecules (ethanol, ethylacetate, toluene) of the SWCNTs-in-CdA nanocomposite increases with the filler content of SWCNTs incorporated in the nanocomposite; also the SWCNTs-in-CdA nanocomposite vapor sensitivity results significantly enhanced with respect to traditional organic molecular cavities materials with a linearity in the frequency change response for a given nanocomposite weight composition and a very low sub-ppm limit of detection.

  18. Microstructure and Properties of Polypropylene/Carbon Nanotube Nanocomposites

    Directory of Open Access Journals (Sweden)

    Dimitrios Bikiaris

    2010-04-01

    Full Text Available In the last few years, great attention has been paid to the preparation of polypropylene (PP nanocomposites using carbon nanotubes (CNTs due to the tremendous enhancement of the mechanical, thermal, electrical, optical and structural properties of the pristine material. This is due to the unique combination of structural, mechanical, electrical, and thermal transport properties of CNTs. However, it is well-known that the properties of polymer-based nanocomposites strongly depend on the dispersion of nanofillers and almost all the discussed properties of PP/CNTs nanocomposites are strongly related to their microstructure. PP/CNTs nanocomposites were, mainly, prepared by melt mixing and in situ polymerization. Young’s modulus, tensile strength and storage modulus of the PP/CNTs nanocomposites can be increased with increasing CNTs content due to the reinforcement effect of CNTs inside the polymer matrix. However, above a certain CNTs content the mechanical properties are reduced due to the CNTs agglomeration. The microstructure of nanocomposites has been studied mainly by SEM and TEM techniques. Furthermore, it was found that CNTs can act as nucleating agents promoting the crystallization rates of PP and the addition of CNTs enhances all other physical properties of PP. The aim of this paper is to provide a comprehensive review of the existing literature related to PP/CNTs nanocomposite preparation methods and properties studies.

  19. Understanding the thermal, mechanical and electrical properties of epoxy nanocomposites

    International Nuclear Information System (INIS)

    Sarathi, R.; Sahu, R.K.; Rajeshkumar, P.

    2007-01-01

    In the present work, the electrical, mechanical and thermal properties of epoxy nanocomposite materials were studied. The electrical insulation characteristics were analyzed through short time breakdown voltage test, accelerated electrical ageing test, and by tracking test. The breakdown voltage increases with increase in nano-clay content up to 5 wt%, under AC and DC voltages. The volume resistivity, permittivity and tan(δ) of the epoxy nanocomposites were measured. The Weibull studies indicate that addition of nanoclay upto 5 wt% enhances the characteristic life of epoxy nanocomposite insulation material. The tracking test results indicate that the tracking time is high with epoxy nanocomposites as compared to pure epoxy. Ageing studies were carried out to understand the surface characteristic variation through contact angle measurement. The hydrophobicity of the insulating material was analysed through contact angle measurement. The diffusion coefficients of the material with different percentage of clay in epoxy nanocomposites were calculated. The exfoliation characteristics in epoxy nanocomposites were analyzed through wide angle X-ray diffraction (WAXD) studies. The thermal behaviour of the epoxy nanocomposites was analyzed by carrying out thermo gravimetric-differential thermal analysis (TG-DTA) studies. Heat deflection temperature of the material was measured to understand the stability of the material for intermittent temperature variation. The dynamic mechanical analysis (DMA) results indicated that storage modulus of the material increases with small amount of clay in epoxy resin. The activation energy of the material was calculated from the DMA results

  20. What does See the Impulse Acoustic Microscopy inside Nanocomposites?

    Science.gov (United States)

    Levin, V. M.; Petronyuk, Y. S.; Morokov, E. S.; Celzard, A.; Bellucci, S.; Kuzhir, P. P.

    The paper presents results of studying bulk microstructure in carbon nanocomposites by impulse acoustic microscopy technique. Nanocomposite materials are in the focus of interest because of their outstanding properties in minimal nanofiller content. Large surface area and high superficial activity cause strong interaction between nanoparticles that can result in formation of fractal conglomerates. This paper involves results of the first direct observation of nanoparticle conglomerates inside the bulk of epoxy-carbon nanocomposites. Diverse types of carbon nanofiller have been under investigation. The impulse acoustic microscope SIAM-1 (Acoustic Microscopy Lab, IBCP RAS) has been employed for 3D imaging bulk microstructure and measuring elastic properties of the nanocomposite specimens. The range of 50-200 MHz allows observing microstructure inside the entire specimen bulk. Acoustic images are obtained in the ultramicroscopic regime; they are formed by the Rayleigh type scattered radiation. It has been found the high-resolution acoustic vision (impulse acoustic microscopy) is an efficient technique to observe mesostructure formed by fractal cluster inside nanocomposites. The clusterization takes its utmost form in nanocomposites with graphite nanoplatelets as nanofiller. The nanoparticles agglomerate into micron-sized conglomerates distributed randomly over the material. Mesostructure in nanocomposites filled with carbon nanotubes is alternation of regions with diverse density of nanotube packing. Regions with alternative density of CNT packing are clearly seen in acoustical images as neighboring pixels of various brightness.

  1. Tangible nanocomposites with diverse properties for heart valve application

    International Nuclear Information System (INIS)

    Vellayappan, Muthu Vignesh; Balaji, Arunpandian; Subramanian, Aruna Priyadarshini; John, Agnes Aruna; Jaganathan, Saravana Kumar; Supriyanto, Eko; Yusof, Mustafa; Murugesan, Selvakumar; Mohandas, Hemanth

    2015-01-01

    Cardiovascular disease claims millions of lives every year throughout the world. Biomaterials are used widely for the treatment of this fatal disease. With the advent of nanotechnology, the use of nanocomposites has become almost inevitable in the field of biomaterials. The versatile properties of nanocomposites, such as improved durability and biocompatibility, make them an ideal choice for various biomedical applications. Among the various nanocomposites, polyhedral oligomeric silsesquioxane-poly(carbonate-urea)urethane, bacterial cellulose with polyvinyl alcohol, carbon nanotubes, graphene oxide and nano-hydroxyapatite nanocomposites have gained popularity as putative choices for biomaterials in cardiovascular applications owing to their superior properties. In this review, various studies performed utilizing these nanocomposites for improving the mechanical strength, anti-calcification potential and hemocompatibility of heart valves are reviewed and summarized. The primary motive of this work is to shed light on the emerging nanocomposites for heart valve applications. Furthermore, we aim to promote the prospects of these nanocomposites in the campaign against cardiovascular diseases. (review)

  2. Multifunctional Magnetic-fluorescent Nanocomposites for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Rakovich Yury

    2008-01-01

    Full Text Available AbstractNanotechnology is a fast-growing area, involving the fabrication and use of nano-sized materials and devices. Various nanocomposite materials play a number of important roles in modern science and technology. Magnetic and fluorescent inorganic nanoparticles are of particular importance due to their broad range of potential applications. It is expected that the combination of magnetic and fluorescent properties in one nanocomposite would enable the engineering of unique multifunctional nanoscale devices, which could be manipulated using external magnetic fields. The aim of this review is to present an overview of bimodal “two-in-one” magnetic-fluorescent nanocomposite materials which combine both magnetic and fluorescent properties in one entity, in particular those with potential applications in biotechnology and nanomedicine. There is a great necessity for the development of these multifunctional nanocomposites, but there are some difficulties and challenges to overcome in their fabrication such as quenching of the fluorescent entity by the magnetic core. Fluorescent-magnetic nanocomposites include a variety of materials including silica-based, dye-functionalised magnetic nanoparticles and quantum dots-magnetic nanoparticle composites. The classification and main synthesis strategies, along with approaches for the fabrication of fluorescent-magnetic nanocomposites, are considered. The current and potential biomedical uses, including biological imaging, cell tracking, magnetic bioseparation, nanomedicine and bio- and chemo-sensoring, of magnetic-fluorescent nanocomposites are also discussed.

  3. Designed graphene-peptide nanocomposites for biosensor applications: A review

    International Nuclear Information System (INIS)

    Wang, Li; Zhang, Yujie; Wu, Aiguo; Wei, Gang

    2017-01-01

    The modification of graphene with biomacromolecules like DNA, protein, peptide, and others extends the potential applications of graphene materials in various fields. The bound biomacromolecules could improve the biocompatibility and bio-recognition ability of graphene-based nanocomposites, therefore could greatly enhance their biosensing performances on both selectivity and sensitivity. In this review, we presented a comprehensive introduction and discussion on recent advance in the synthesis and biosensor applications of graphene-peptide nanocomposites. The biofunctionalization of graphene with specifically designed peptides, and the synthesis strategies of graphene-peptide (monomer, nanofibrils, and nanotubes) nanocomposites were demonstrated. On the other hand, the fabrication of graphene-peptide nanocomposite based biosensor architectures for electrochemical, fluorescent, electronic, and spectroscopic biosensing were further presented. This review includes nearly all the studies on the fabrication and applications of graphene-peptide based biosensors recently, which will promote the future developments of graphene-based biosensors in biomedical detection and environmental analysis. - Highlights: • A comprehensive review on the fabrication and application of graphene-peptide nanocomposites was presented. • The design of peptide sequences for biofunctionalization of various graphene materials was presented. • Multi-strategies on the fabrication of biosensors with graphene-peptide nanocomposites were discussed. • Designed graphene-peptide nanocomposites showed wide biosensor applications.

  4. Cellulose whisker/epoxy resin nanocomposites.

    Science.gov (United States)

    Tang, Liming; Weder, Christoph

    2010-04-01

    New nanocomposites composed of cellulose nanofibers or "whiskers" and an epoxy resin were prepared. Cellulose whiskers with aspect ratios of approximately 10 and approximately 84 were isolated from cotton and sea animals called tunicates, respectively. Suspensions of these whiskers in dimethylformamide were combined with an oligomeric difunctional diglycidyl ether of bisphenol A with an epoxide equivalent weight of 185-192 and a diethyl toluenediamine-based curing agent. Thin films were produced by casting these mixtures and subsequent curing. The whisker content was systematically varied between 4 and 24% v/v. Electron microscopy studies suggest that the whiskers are evenly dispersed within the epoxy matrix. Dynamic mechanical thermoanalysis revealed that the glass transition temperature (T(g)) of the materials was not significantly influenced by the incorporation of the cellulose filler. Between room temperature and 150 degrees C, i.e., below T(g), the tensile storage moduli (E') of the nanocomposites increased modestly, for example from 1.6 GPa for the neat polymer to 4.9 and 3.6 GPa for nanocomposites comprising 16% v/v tunicate or cotton whiskers. The relative reinforcement was more significant at 185 degrees C (i.e., above T(g)), where E' was increased from approximately 16 MPa (neat polymer) to approximately 1.6 GPa (tunicate) or approximately 215 MPa (cotton). The mechanical properties of the new materials are well-described by the percolation model and are the result of the formation of a percolating whisker network in which stress transfer is facilitated by strong interactions between the whiskers.

  5. Viscoelastic Analysis of Thermally Stiffening Polymer Nanocomposites

    Science.gov (United States)

    Ehlers, Andrew; Rende, Deniz; Senses, Erkan; Akcora, Pinar; Ozisik, Rahmi

    Poly(ethylene oxide), PEO, filled with silica nanoparticles coated with poly(methyl methacrylate), PMMA, was shown to present thermally stiffening behavior above the glass transition temperature of both PEO and PMMA. In the current study, the viscoelastic beahvior of this nanocomposite system is investigated via nanoindenation experiments to complement on going rheological studies. Results were compared to neat polymers, PEO and PMMA, to understand the effect of coated nanoparticles. This material is based upon work supported by the National Science Foundation under Grant No. CMMI-1538730.

  6. Polymer-noble metal nanocomposites: Review

    CSIR Research Space (South Africa)

    Folarin, OM

    2011-09-01

    Full Text Available because of their multi-functionality, ease of process-ability, potential for large-scale manufacturing, significantly lighter than metals, ease of synthesis when compared to the oxide/noble metal multi-layers (Gass et al., 2006; Lee et al., 2003.... their easy aggregation arising from their high surface free energy (Lee et al., 2006). In the design of nanocomposites, one must consider the properties of the polymer matrix as well as the stability of the nanoparticles and more importantly...

  7. SBR Brazilian organophilic/clay nanocomposites

    International Nuclear Information System (INIS)

    Guimaraes, Thiago R.; Valenzuela-Diaz, Francisco R.; Morales, Ana Rita; Paiva, Lucilene B.

    2009-01-01

    The aim of this work is the obtaining of SBR composites using a Brazilian raw bentonite and the same bentonite treated with an organic salt. The clays were characterized by XRD. The clay addition in the composites was 10 pcr. The composites were characterized by XRD and had measured theirs tension strength (TS). The composite with Brazilian treated clay showed TS 233% higher than a composite with no clay, 133% higher than a composite with Cloisite 30B organophilic clay and 17% lower than a composite with Cloisite 20 A organophilic clay. XRD and TS data evidence that the composite with Brazilian treated clay is an intercalated nanocomposite. (author)

  8. Functional Carbon Nanocomposite, Optoelectronic, and Catalytic Coatings

    Science.gov (United States)

    Liang, Yu Teng

    Over the past couple decades, fundamental research into carbon nanomaterials has produced a steady stream of groundbreaking physical science. Their record setting mechanical strength, chemical stability, and optoelectronic performance have fueled many optimistic claims regarding the breadth and pace of carbon nanotube and graphene integration. However, present synthetic, processing, and economic constraints have precluded these materials from many practical device applications. To overcome these limitations, novel synthetic techniques, processing methodologies, device geometries, and mechanistic insight were developed in this dissertation. The resulting advancements in material production and composite device performance have brought carbon nanomaterials ever closer to commercial implementation. For improved materials processing, vacuum co-deposition was first demonstrated as viable technique for forming carbon nanocomposite films without property distorting covalent modifications. Co-deposited nanoparticle, carbon nanotube, and graphene composite films enabled rapid device prototyping and compositional optimization. Cellulosic polymer stabilizers were then shown to be highly effective carbon nanomaterial dispersants, improving graphene production yields by two orders of magnitude in common organic solvents. By exploiting polarity interactions, iterative solvent exchange was used to further increase carbon nanomaterial dispersion concentrations by an additional order of magnitude, yielding concentrated inks. On top of their low causticity, these cellulosic nanomaterial inks have highly tunable viscosities, excellent film forming capacity, and outstanding thermal stability. These processing characteristics enable the efficient scaling of carbon nanomaterial coatings and device production using existing roll-to-roll fabrication techniques. Utilizing these process improvements, high-performance gas sensing, energy storage, transparent conductor, and photocatalytic

  9. Repeat Sequence Proteins as Matrices for Nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Drummy, L.; Koerner, H; Phillips, D; McAuliffe, J; Kumar, M; Farmer, B; Vaia, R; Naik, R

    2009-01-01

    Recombinant protein-inorganic nanocomposites comprised of exfoliated Na+ montmorillonite (MMT) in a recombinant protein matrix based on silk-like and elastin-like amino acid motifs (silk elastin-like protein (SELP)) were formed via a solution blending process. Charged residues along the protein backbone are shown to dominate long-range interactions, whereas the SELP repeat sequence leads to local protein/MMT compatibility. Up to a 50% increase in room temperature modulus and a comparable decrease in high temperature coefficient of thermal expansion occur for cast films containing 2-10 wt.% MMT.

  10. Ordered mesoporous silica-based inorganic nanocomposites

    International Nuclear Information System (INIS)

    Wang Qingqing; Shantz, Daniel F.

    2008-01-01

    This article reviews the synthesis and characterization of nanoparticles and nanowires grown in ordered mesoporous silicas (OMS). Summarizing work performed over the last 4 years, this article highlights the material properties of the final nanocomposite in the context of the synthesis methodology employed. While certain metal-OMS systems (e.g. gold in MCM-41) have been extensively studied this article highlights that there is a rich set of chemistries that have yet to be explored. The article concludes with some thoughts on future developments and challenges in this area. - Graphical abstract: HAADF TEM image of gold nanoparticles in amine-functionalized MCM-41 (from Ref. [22])

  11. Biopolymer based nanocomposites reinforced with graphene nanoplatelets

    Energy Technology Data Exchange (ETDEWEB)

    Botta, L.; Scaffaro, R.; Mistretta, M. C.; La Mantia, F. P. [Dipartimento di Ingegneria Civile, Ambientale, Aerospaziale, dei Materiali, Università di Palermo, UdR INSTM di Palermo, Viale delle Scienze, 90128 Palermo (Italy)

    2016-05-18

    In this work, biopolymer based nanocomposites filled with graphene nanoplatelets (GnP) were prepared by melt compounding in a batch mixer. The polymer used as matrix was a commercial biodegradable polymer-blend of PLA and a copolyester (BioFlex®). The prepared materials were characterized by scanning electron microscopy (SEM), rheological and mechanical measurements. Moreover, the effect of the GnP amount on the investigated properties was evaluated. The results indicated that the incorporation of GnP increased the stiffness of the biopolymeric matrix.

  12. Epoxy Nanocomposites Containing Zeolitic Imidazolate Framework-8.

    Science.gov (United States)

    Liu, Cong; Mullins, Michael; Hawkins, Spencer; Kotaki, Masaya; Sue, Hung-Jue

    2018-01-10

    Zeolitic imidazole framework-8 (ZIF-8) is utilized as a functional filler and a curing agent in the preparation of epoxy nanocomposites. The imidazole group on the surface of the ZIF-8 initiates epoxy curing, resulting in covalent bonding between the ZIF-8 crystals and epoxy matrix. A substantial reduction in dielectric constant and increase in tensile modulus were observed. The implication of the present study for utilization of metal-organic framework to improve physical and mechanical properties of polymeric matrixes is discussed.

  13. Thermomechanical Behavior of High Performance Epoxy/Organoclay Nanocomposites

    Directory of Open Access Journals (Sweden)

    Artur Soares Cavalcanti Leal

    2014-01-01

    Full Text Available Nanocomposites of epoxy resin containing bentonite clay were fabricated to evaluate the thermomechanical behavior during heating. The epoxy resin system studied was prepared using bifunctional diglycidyl ether of bisphenol A (DGEBA, crosslinking agent diaminodiphenylsulfone (DDS, and diethylenetriamine (DETA. The purified bentonite organoclay (APOC was used in all experiments. The formation of nanocomposite was confirmed by X-ray diffraction analysis. Specimens of the fabricated nanocomposites were characterized by dynamic mechanical analysis (DMA. According to the DMA results a significant increase in glass transition temperature and storage modulus was evidenced when 1 phr of clay is added to epoxy resin.

  14. Polymer nanocomposite of laponite RD prepared by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Maria J.A.; Silva, Estefania O.; Lugao, Ademar Benevolo; Parra, Duclerc Fernandes, E-mail: mariajhho@yahoo.com.br, E-mail: dfparra@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Amato, Valdir S. [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Hospital de Clinicas. Divisao de Doencas Infecciosas e Parasitarias

    2012-07-01

    Nanocomposite hydrogels based on polyvinyl alcohol (PVAl) and polyvinylpyrrolidone (PVP) containing 0-5 wt % of the synthetic laponite RD clay were prepared by gamma irradiation process. The morphology of the nanocomposite hydrogel was observed by characterizations techniques using: scanning electron microscopy (SEM) and atomic force microscopy (AFM). The structural properties crosslinking was determined by measuring the crosslink gel content extraction on mesh 500 sizes and swelling kinetics at 22 °C. The results showed that crosslinks have inverse dependence on the clay level in the nanocomposite hydrogels, while swelling shows direct dependence. (author)

  15. Development and synthesis nanocompositions DLC coatings with orientation effect

    International Nuclear Information System (INIS)

    Levchenko, V.A.; Novoselova, N.V.; Matveenko, V.N.

    2008-01-01

    On the basis of volume modelling and a detailed experimental research of physical and chemical properties nanocompositions DLC with one-dimensional highly orientationally the carbon structure on interphase border of section with lubricant as models tribological knot, proves typical models of synthesis new nanocompositions the DLC possessing high tribological properties (by high wear resistance, low of a friction, etc.). The influence mechanism orientation properties of a surface of the synthesized coatings on molecular in a boundary lubricant layer is investigated. On basis tribological experimental batch tests nanocompositions the carbon coatings possessing orientation effect, the synthesis mechanism highly orientationally DLC coatings with optimum tribological properties is developed.

  16. Effect of irradiation in nanocomposite films of LLDPE

    International Nuclear Information System (INIS)

    Jagtap, R.N.; Shaikh, J.; Anandakrishnan, R.; Sharma, A.K.; Varier, P.S.

    2009-01-01

    Melt compounding was used for the preparation of LLDPE/MMT nanocomposite. The films were irradiated with gamma irradiation to study its mechanical, optical, thermal properties, barrier properties. Montmorillonite clay was treated with cationic emulsifier, to modify the surface properties by HCl and functionalizing with acetic acid. These treated clays were then incorporated in LLDPE to prepare nanocomposite films and then it is irradiated with gamma rays for different dosages of irradiation varying from 0 to 30 kGy, which can be used for food packaging applications. These nanocomposites were characterized by XRD and FTIR. (author)

  17. Morphology study of polyamide 6/bentonite clay nanocomposites

    International Nuclear Information System (INIS)

    Paz, Rene A.; Araujo, Edcleide M.; Melo, Tomas J.A.; Leite, Amanda M.D.; Medeiros, Vanessa Nobrega; Pessan, Luiz A.; Passador, Fabio R.

    2011-01-01

    Polymer/clay nanocomposites have had much attention in recent years, especially those developed with layered silicates, due to the need for engineering materials more efficient than pure polymers for certain applications. The level of exfoliation of layered silicates in the crystalline structure of polymer matrices has been studied and it has been observed that it affects the behavior of crystalline and therefore the mechanical and physical properties. In this study, polyamide 6 nanocomposites were obtained by the melt intercalation technique, using regional bentonite clay modified with a quaternary ammonium salt in an amount of 3% by weight. XRD and TEM tests showed obtaining nanocomposites with exfoliated structures (author)

  18. Magneto optical properties of silver doped magnetic nanocomposite material

    Directory of Open Access Journals (Sweden)

    N. Abirami

    2017-11-01

    Full Text Available Magnetic composite materials challenge traditional materials in broad applications such as transformer, sensors and electrical motors. In this work by studying the permittivity and permeability spectra of silver doped magnetic nanocomposite system, the variation of the effective refractive index with frequency is investigated for different filling factor. It is found that the value of resonance frequency decrease with filling factor. The polariton dispersion of the system is also studied. This study of the nanocomposite system can be exploited in designing modern optical devices.PACS: 75.50-y, 71.36.+c, 78.67.Sc, 78.20.Ci. Keywords: Permittivity, Permeability, Nanocomposite system, Polariton

  19. Research Progress in Graphene/Rubber Conducting Nanocomposites

    Directory of Open Access Journals (Sweden)

    DONG Hui-min

    2017-03-01

    Full Text Available The conductive mechanism of graphene/rubber nanocomposites was introduced.Advances in the synthesis and properties of graphene and its derivatives, modifications of graphene, along with its hybrid fillers, as well as fabrication of related rubber conducting nanocomposites were reviewed.Many factors affecting the electrical properties, such as fabrication method, vulcanization, temperature, pressure, frequency and media etc. were also summarized.It was pointed out that the further research should be focused on multi-component graphene/rubber nanocomposites and its double percolation phenomenon.

  20. Mechanical properties and thermal behaviour of LLDPE/MWNTs nanocomposites

    Directory of Open Access Journals (Sweden)

    Tai Jin-hua

    2012-12-01

    Full Text Available Multi-walled carbon nanotubes (MWNTs were incorporated into a linear low-density polyethylene (LLDPE matrix through using screw extrusion and injection technique. The effect of different weight percent loadings of MWNTs on the morphology, mechanical, and thermal of LLDPE/MWNTs nanocomposite had been investigated. It was found that, at low concentration of MWNTs, it could uniformly disperse into a linear low-density polyethylene matrix and provide LLDPE/MWNTs nanocomposites much improved mechanical properties. Thermal analysis showed that a clear improvement of thermal stability for LLDPE/MWNTs nanocomposites increased with increasing MWNTs content.

  1. Microstructure of polymer-clay nanocomposites studied by positrons

    International Nuclear Information System (INIS)

    Wang, S.J.; Liu, L.M.; Fang, P.F.; Chen, Z.; Wang, H.M.; Zhang, S.P.

    2007-01-01

    The epoxy-rectorite nanocomposites with different rectorite contents, epoxide equivalent were prepared and its microstructure was studied by positron annihilation and X-ray diffraction (XRD). At low rectorite content (0-2.0%), the free volume size in nanocomposites is nearly the same, but its concentration decreases with increasing content; the exfoliated structure was observed by XRD and interfacial layer formation between rectorite platelets and epoxy matrix was probed by positrons. Comparing with epoxy-montmorillonite, the exfoliated structure and interfacial layers are easier formed in epoxy-rectorite nanocomposites

  2. Polymer nanocomposite of laponite RD prepared by gamma irradiation

    International Nuclear Information System (INIS)

    Oliveira, Maria J.A.; Silva, Estefania O.; Lugao, Ademar Benevolo; Parra, Duclerc Fernandes; Amato, Valdir S.

    2012-01-01

    Nanocomposite hydrogels based on polyvinyl alcohol (PVAl) and polyvinylpyrrolidone (PVP) containing 0-5 wt % of the synthetic laponite RD clay were prepared by gamma irradiation process. The morphology of the nanocomposite hydrogel was observed by characterizations techniques using: scanning electron microscopy (SEM) and atomic force microscopy (AFM). The structural properties crosslinking was determined by measuring the crosslink gel content extraction on mesh 500 sizes and swelling kinetics at 22 °C. The results showed that crosslinks have inverse dependence on the clay level in the nanocomposite hydrogels, while swelling shows direct dependence. (author)

  3. Use of MMT and MMT organoclay in production of starch nanocomposites

    International Nuclear Information System (INIS)

    Schlemmer, D.; Sales, M.J.A.; Macedo, J.L. de; Angelica, R.S.

    2010-01-01

    Starch can be used to replace petrochemical plastics for short shelf life. However, starch films have poor mechanical strength and sensitivity to moisture. This can be improved through the incorporation of nanoclays, such as montmorillonite, forming nanocomposites. Nanocomposites were prepared with 1, 3, 5 and 10% of montmorillonite, using pequi oil as plasticizer. The clay was also modified with a quaternary ammonium salt. The clays were characterized by XRF, XRD, IR and TG. Results confirmed the organophilization. The nanocomposites diffractograms showed that the addition of small amounts of clay produces delaminated nanocomposites. Already the addition of larger amount of clay does not form nanocomposites, or leads to the formation of intercalated nanocomposites. (author)

  4. Nanocomposite Strain Gauges Having Small TCRs

    Science.gov (United States)

    Gregory, Otto; Chen, Ximing

    2009-01-01

    Ceramic strain gauges in which the strain-sensitive electrically conductive strips made from nanocomposites of noble metal and indium tin oxide (ITO) are being developed for use in gas turbine engines and other power-generation systems in which gas temperatures can exceed 1,500 F (about 816 C). In general, strain gauges exhibit spurious thermally induced components of response denoted apparent strain. When temperature varies, a strain-gauge material that has a nonzero temperature coefficient of resistance (TCR) exhibits an undesired change in electrical resistance that can be mistaken for the change in resistance caused by a change in strain. It would be desirable to formulate straingauge materials having TCRs as small as possible so as to minimize apparent strain. Most metals exhibit positive TCRs, while most semiconductors, including ITO, exhibit negative TCRs. The present development is based on the idea of using the negative TCR of ITO to counter the positive TCRs of noble metals and of obtaining the benefit of the ability of both ITO and noble metals to endure high temperatures. The noble metal used in this development thus far has been platinum. Combinatorial libraries of many ceramic strain gauges containing nanocomposites of various proportions of ITO and platinum were fabricated by reactive co-sputtering from ITO and platinum targets onto alumina- and zirconia-based substrates mounted at various positions between the targets.

  5. Synthesis and characterization of functional magnetic nanocomposites

    Science.gov (United States)

    Gass, J.; Sanders, J.; Srinath, S.; Srikanth, H.

    2006-03-01

    Magnetic nanoparticles and carbon nanotubes have been excellent functional materials that could be dispersed in polymer matrices for various applications. However, uniform dispersion of particles in polymers without agglomeration is quite challenging. We have fabricated PMMA/polypyrrole bilayer structures embedded with Fe3O4 magnetite nanoparticles synthesized using wet chemical synthesis. Agglomeration-free dispersion of nanoparticles was achieved by coating the particles with surfactants and by dissolving both the particles and PMMA in chlorobenzene. Structural characterization was done using XRD and TEM. Magnetic properties of the bilayer structures indicated superparamagnetic behavior that is desirable for RF applications as the magnetic losses are reduced. Our polymer nanocomposite bilayer films with conducting polymer coatings are potential candidates for tunable RF applications with integrated EMI suppression. We will also report on our studies of pumped ferrofluids flowing past carbon nanotubes that are arranged in microchannel arrays. Magnetization under various flow conditions is investigated and correlated with the hydrodynamic properties. This scheme provides a novel method of energy conversion and storage using nanocomposite materials.

  6. Review of Plasmonic Nanocomposite Metamaterial Absorber

    Directory of Open Access Journals (Sweden)

    Mehdi Keshavarz Hedayati

    2014-02-01

    Full Text Available Plasmonic metamaterials are artificial materials typically composed of noble metals in which the features of photonics and electronics are linked by coupling photons to conduction electrons of metal (known as surface plasmon. These rationally designed structures have spurred interest noticeably since they demonstrate some fascinating properties which are unattainable with naturally occurring materials. Complete absorption of light is one of the recent exotic properties of plasmonic metamaterials which has broadened its application area considerably. This is realized by designing a medium whose impedance matches that of free space while being opaque. If such a medium is filled with some lossy medium, the resulting structure can absorb light totally in a sharp or broad frequency range. Although several types of metamaterials perfect absorber have been demonstrated so far, in the current paper we overview (and focus on perfect absorbers based on nanocomposites where the total thickness is a few tens of nanometer and the absorption band is broad, tunable and insensitive to the angle of incidence. The nanocomposites consist of metal nanoparticles embedded in a dielectric matrix with a high filling factor close to the percolation threshold. The filling factor can be tailored by the vapor phase co-deposition of the metallic and dielectric components. In addition, novel wet chemical approaches are discussed which are bio-inspired or involve synthesis within levitating Leidenfrost drops, for instance. Moreover, theoretical considerations, optical properties, and potential application of perfect absorbers will be presented.

  7. Nanocomposites as Advanced Materials for Aerospace Industry

    Directory of Open Access Journals (Sweden)

    George PELIN

    2012-12-01

    Full Text Available Polymer nanocomposites, consisting of nanoparticles dispersed in polymer matrix, have gained interest due to the attractive properties of nanostructured fillers, as carbon nanotubes and layered silicates. Low volume additions (1- 5% of nanoparticles provide properties enhancements comparable to those achieved by conventional loadings (15- 40% of traditional fillers.Structural nanocomposites represent reinforcement structures based on carbon or glass fibers embedded into polymeric matrix modified with nanofillers.Structural composites are the most important application of nanaocomposites, in aerospace field, as, laminates and sandwich structures. Also, they can by used as anti-lightning, anti-radar protectors and paints. The paper presents the effects of sonic dispersion of carbon nanotubes and montmorrilonite on the mechanical, electrical, rheological and trybological properties of epoxy polymers and laminated composites, with carbon or glass fiber reinforcement, with nanoadditivated epoxy matrix. One significant observation is that nanoclay contents higher than 2% wt generate an increase of the resin viscosity, from 1500 to 50000- 100000 cP, making the matrix impossible to use in high performance composites.Also, carbon nanotubes provide the resin important electrical properties, passing from dielectric to semi- conductive class. These effects have also been observed for fiber reinforced composites.Contrarily to some opinions in literature, the results of carbon nanotubes or nanoclays addition on the mechanical characteristics of glass or carbon fiber composites seem to be rather low.

  8. A single magnetic nanocomposite cilia force sensor

    KAUST Repository

    Alfadhel, Ahmed

    2016-04-20

    The advancements in fields like robotics and medicine continuously require improvements of sensor devices and more engagement of cooperative sensing technologies. For example, instruments such as tweezers with sensitive force sensory heads could provide the ability to sense a variety of physical quantities in real time, such as the amount and direction of the force applied or the texture of the gripped object. Force sensors with such abilities could be great solutions toward the development of smart surgical tools. In this work, a unique force sensor that can be integrated at the tips of robotic arms or surgical tools is reported. The force sensor consists of a single bioinspired, permanent magnetic and highly elastic nanocomposite cilia integrated on a magnetic field sensing element. The nanocomposite is prepared from permanent magnetic nanowires incorporated into the highly elastic polydimethylsiloxane. We demonstrate the potential of this concept by performing several experiments to show the performance of the force sensor. The developed sensor element has a 200 μm in diameter single cilium with 1:5 aspect ratio and shows a detection range up to 1 mN with a sensitivity of 1.6 Ω/mN and a resolution of 31 μN. The simple fabrication process of the sensor allows easy optimization of the sensor performance to meet the needs of different applications.

  9. Combustion of environmentally altered molybdenum trioxide nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Kevin; Pantoya, Michelle L. [Mechanical Engineering Department, Texas Tech University, 2500 Broadway, Lubbock, TX 79409 (United States)

    2006-06-15

    Nanocomposite thermite mixtures are currently under development for many primer applications due to their high energy densities, high ignition sensitivity, and low release of toxins into the environment. However, variability and inconsistencies in combustion performance have not been sufficiently investigated. Environmental interactions with the reactants are thought to be a contributing factor to these variabilities. Combustion velocity experiments were conducted on aluminum (Al) and molybdenum trioxide (MoO{sub 3}) mixtures to investigate the role of environmental interactions such as light exposure and humidity. While the Al particles were maintained in an ambient, constant environment, the MoO{sub 3} particles were exposed to UV or fluorescent light, and highly humid environments. Results show that UV and fluorescent lighting over a period of days does not significantly contribute to performance deterioration. However, a humid environment severely decreases combustion performance if the oxidizer particles are not heat-treated. Heat treatment of the MoO{sub 3} greatly increases the material's ability to resist water absorption, yielding more repeatable combustion performance. This work further quantifies the role of the environment in the decrease of combustion performance of nanocomposites over time. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  10. Carbon-polyaniline nanocomposites as supercapacitor materials

    Science.gov (United States)

    Sathish Kumar, M.; Yamini Yasoda, K.; Batabyal, Sudip Kumar; Kothurkar, Nikhil K.

    2018-04-01

    Polyaniline-based nanocomposites containing carbon nanotubes (CNT), reduced graphene oxide (rGO) and mixture of CNTs and rGO were synthesized. UV-visible spectroscopy and FT-IR spectroscopy confirmed the presence of polyaniline (PANi) and carbon nanomaterials. Scanning electron microscopy revealed that the neat PANi had a granular morphology, which can lead to increased electrical resistance to high interfacial resistance between domains of PANi. Cyclic voltammetry of PANi, PANi/CNT, PANi/rGO and PANi/CNT/rGO showed that in general, specific capacitance reduces with increasing scan rate within the range (10–100 mV s‑1). Also the specific capacitance values at any given scan rate within the above range, for PANi, PANi/CNT, PANi/rGO and PANi/CNT/rGO were found to be in increasing order. The specific capacitance of the PANi/CNT/rGO nanocomposite as measured by galvanostatic charge-discharge measurements, was found to be 312.5 F g‑1. The introduction of the carbon nanomaterials (CNTs, rGO) in PANi in general leads to improved specific capacitance, while the addition of CNTs and rGO together leads to synergistic improvement in the specific capacitance, owing to a combination of factors.

  11. Nanocomposite Electrospun Nanofiber Membranes for Environmental Remediation.

    Science.gov (United States)

    Homaeigohar, Shahin; Elbahri, Mady

    2014-02-10

    Rapid worldwide industrialization and population growth is going to lead to an extensive environmental pollution. Therefore, so many people are currently suffering from the water shortage induced by the respective pollution, as well as poor air quality and a huge fund is wasted in the world each year due to the relevant problems. Environmental remediation necessitates implementation of novel materials and technologies, which are cost and energy efficient. Nanomaterials, with their unique chemical and physical properties, are an optimum solution. Accordingly, there is a strong motivation in seeking nano-based approaches for alleviation of environmental problems in an energy efficient, thereby, inexpensive manner. Thanks to a high porosity and surface area presenting an extraordinary permeability (thereby an energy efficiency) and selectivity, respectively, nanofibrous membranes are a desirable candidate. Their functionality and applicability is even promoted when adopting a nanocomposite strategy. In this case, specific nanofillers, such as metal oxides, carbon nanotubes, precious metals, and smart biological agents, are incorporated either during electrospinning or in the post-processing. Moreover, to meet operational requirements, e.g., to enhance mechanical stability, decrease of pressure drop, etc. , nanofibrous membranes are backed by a microfibrous non-woven forming a hybrid membrane. The novel generation of nanocomposite/hybrid nanofibrous membranes can perform extraordinarily well in environmental remediation and control. This reality justifies authoring of this review paper.

  12. Nanocomposite Electrospun Nanofiber Membranes for Environmental Remediation

    Directory of Open Access Journals (Sweden)

    Shahin Homaeigohar

    2014-02-01

    Full Text Available Rapid worldwide industrialization and population growth is going to lead to an extensive environmental pollution. Therefore, so many people are currently suffering from the water shortage induced by the respective pollution, as well as poor air quality and a huge fund is wasted in the world each year due to the relevant problems. Environmental remediation necessitates implementation of novel materials and technologies, which are cost and energy efficient. Nanomaterials, with their unique chemical and physical properties, are an optimum solution. Accordingly, there is a strong motivation in seeking nano-based approaches for alleviation of environmental problems in an energy efficient, thereby, inexpensive manner. Thanks to a high porosity and surface area presenting an extraordinary permeability (thereby an energy efficiency and selectivity, respectively, nanofibrous membranes are a desirable candidate. Their functionality and applicability is even promoted when adopting a nanocomposite strategy. In this case, specific nanofillers, such as metal oxides, carbon nanotubes, precious metals, and smart biological agents, are incorporated either during electrospinning or in the post-processing. Moreover, to meet operational requirements, e.g., to enhance mechanical stability, decrease of pressure drop, etc., nanofibrous membranes are backed by a microfibrous non-woven forming a hybrid membrane. The novel generation of nanocomposite/hybrid nanofibrous membranes can perform extraordinarily well in environmental remediation and control. This reality justifies authoring of this review paper.

  13. A single magnetic nanocomposite cilia force sensor

    KAUST Repository

    Alfadhel, Ahmed; Khan, Mohammed Asadullah; Cardoso, Susana; Kosel, Jü rgen

    2016-01-01

    The advancements in fields like robotics and medicine continuously require improvements of sensor devices and more engagement of cooperative sensing technologies. For example, instruments such as tweezers with sensitive force sensory heads could provide the ability to sense a variety of physical quantities in real time, such as the amount and direction of the force applied or the texture of the gripped object. Force sensors with such abilities could be great solutions toward the development of smart surgical tools. In this work, a unique force sensor that can be integrated at the tips of robotic arms or surgical tools is reported. The force sensor consists of a single bioinspired, permanent magnetic and highly elastic nanocomposite cilia integrated on a magnetic field sensing element. The nanocomposite is prepared from permanent magnetic nanowires incorporated into the highly elastic polydimethylsiloxane. We demonstrate the potential of this concept by performing several experiments to show the performance of the force sensor. The developed sensor element has a 200 μm in diameter single cilium with 1:5 aspect ratio and shows a detection range up to 1 mN with a sensitivity of 1.6 Ω/mN and a resolution of 31 μN. The simple fabrication process of the sensor allows easy optimization of the sensor performance to meet the needs of different applications.

  14. Characterization of nanocomposites PHBV/attapulgite organophilic

    International Nuclear Information System (INIS)

    Silva, L.C.A.; Barreto, L.S.; Thire, R.M.S.M.

    2010-01-01

    Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) - PHBV is a biodegradable polyester which have been studied as an option for the production of disposable goods. This thermoplastic has some disadvantages that limit its use in industrial scale applications: the relative difficulty of processing, high degree of crystallinity and high cost of production relative to conventional polymers. An alternative to improve the properties of PHBV is the incorporation of small amounts of clay to the polymer. The aim of this work was to produce and characterize PHBV nanocomposites reinforced with organophilic attapulgite in different compositions. Natural attapulgite was modified with hexadecylmethylammonium chloride. The nanocomposites were characterized by XRD, SEM and Thermal analysis. It was observed reduction of the degree of crystallinity, melting and glass transition temperatures and the thermal stability of polymer in function on the addition of clay to the matrix of the PHBV. The best results were obtained for PHBV films containing 3% and 5% attapulgite. These films presented a slight increasing in processing window and decreasing in crystalline temperature and in degree of crystallinity as compared to pure PHBV. (author)

  15. Mechanical and Thermal Characterization of Silica Nanocomposites

    Science.gov (United States)

    Cunningham, Anthony Lamar

    Polymer nanocomposites are a class of materials containing nanoparticles with a large interfacial surface area. Only a small quantity of nanoparticles are needed to provide superior multifunctional properties; such as mechanical, thermal, electrical, and moisture absorption properties in polymers. Nanoparticles tend to agglomerate, so special techniques are required for homogeneous distribution. Nanosilica is now readily available as colloidal sols, for example; Nanopox RTM F400 (supplied by Evonik Nanoresins AG, Germany). The nanoparticles are first synthesized from aqueous sodium silicate solution, and then undergo a surface modification process with organosilane and matrix exchange. F400 contains 40%wt silica nanoparticles colloidally dispersed in a DGEBA epoxy resin. The mean particle diameter is about 20 nm with a narrow distribution range of about 5 to 35 nm. The objectives of this study are to develop a reproducible processing method for nanosilica enhanced resin systems used in the manufacturing of fiber reinforced composites that will be characterized for mechanical and thermal properties. Research has concluded that shows improvements in the properties of the matrix material when processed in loading variations of 0 to 25%wt silica nanoparticles. The loadings were also used to manufacture fiberglass reinforced nanocomposite laminates and also tested for mechanical and thermal properties.

  16. Nanocomposite permanent magnetic materials Nd-Fe-B type: The influence of nanocomposite on magnetic properties

    Directory of Open Access Journals (Sweden)

    Talijan Nadežda M.

    2005-01-01

    Full Text Available The influence on the magnetic properties of nanocristalline ribbons and powders has character of microstructure, between others – the grain size volume of hard and soft magnetic phases and their distribution. Magnetic properties of ribbons and powders depend mainly on their chemical composition and parameters of their heat treatment [1]. Technology of magnets from nanocristalline ribbon consists of the following process: preparing the Nd-Fe- B alloy, preparing the ribbon, powdering of the ribbon, heat treatment of the powder and finally preparing the magnets. Nanocomposite permanent magnet materials based on Nd-Fe- B alloy with Nd low content are a new type of permanent magnetic material. The microstructure of this nanocomposite permanent magnet is composed of a mixture of magnetically soft and hard phases which provide so called exchange coupling effect.

  17. Properties and applications of polymer nanocomposites clay and carbon based polymer nanocomposites

    CERN Document Server

    Prasad Sahoo, Bibhu

    2017-01-01

    The aim of the present edited book is to furnish scientific information about manufacturing, properties, and application of clay and carbon based polymer nanocomposites. It can be used as handbook for undergraduate and post graduate courses (for example material science and engineering, polymer science and engineering, rubber technology, manufacturing engineering, etc.) as well as as reference book for research fellows and professionals. Polymer nanocomposites have received outstanding importance in the present decade because of their broad range of high-performance applications in various areas of engineering and technology due to their special material properties. A great interest is dedicated to nanofiller based polymeric materials, which exhibit excellent enhancement in macroscopic material properties (mechanical, thermal, dynamic mechanical, electrical and many more) at very low filler contents and can therefore be used for the development of next-generation composite materials.

  18. Preparation of novel polymer–metal oxide nanocomposites with ...

    Indian Academy of Sciences (India)

    Administrator

    inorganic compound. Nanocomposites ... ganic compound (nanophase separated structure). This ..... AFM images of (a) titanium substrate, (b) titanium substrate with polymer brush and ... titanium was observed with atomic force microscope.

  19. Photocatalysis and Bandgap Engineering Using ZnO Nanocomposites

    Directory of Open Access Journals (Sweden)

    Muhammad Ali Johar

    2015-01-01

    Full Text Available Nanocomposites have a great potential to work as efficient, multifunctional materials for energy conversion and photoelectrochemical reactions. Nanocomposites may reveal more improved photocatalysis by implying the improvements of their electronic and structural properties than pure photocatalyst. This paper presents the recent work carried out on photoelectrochemical reactions using the composite materials of ZnO with CdS, ZnO with SnO2, ZnO with TiO2, ZnO with Ag2S, and ZnO with graphene and graphene oxide. The photocatalytic efficiency mainly depends upon the light harvesting span of a material, lifetime of photogenerated electron-hole pair, and reactive sites available in the photocatalyst. We reviewed the UV-Vis absorption spectrum of nanocomposite and photodegradation reported by the same material and how photodegradation depends upon the factors described above. Finally the improvement in the absorption band edge of nanocomposite material is discussed.

  20. Photodeposited metal-semiconductor nanocomposites and their applications

    Directory of Open Access Journals (Sweden)

    Yoonkyung Lee

    2018-06-01

    Full Text Available While two-dimensional layered nanomaterials including transition metal oxides and transition metal dichalcogenides have been widely researched because of their unique electronic and optical properties, they still have some limitations. To overcome these limitations, transition metal oxides and transition metal dichalcogenides based nanocomposites have been developed using various methods and have exhibited superior properties. In this paper, we introduce the photodeposition method and review the photodeposition of metal nanoparticles on the surface of transition metal oxide and transition metal dichalcogenides. Their current applications are also explained, such as photocatalysis, hydrogen evolution reaction, surface enhanced Ramanscattering, etc. This approach for nanocomposites has potential for future research areas such as photocatalysis, hydrogen evolution reaction, surface enhanced Raman scattering, and other applications. This approach for nanocomposite has the potential for future research areas. Keywords: Photodeposition, Nanocomposite, Transition metal oxide, Transition metal dichalcogenide

  1. Rapid synthesis of flexible conductive polymer nanocomposite films

    International Nuclear Information System (INIS)

    Blattmann, C O; Sotiriou, G A; Pratsinis, S E

    2015-01-01

    Polymer nanocomposite films with nanoparticle-specific properties are sought out in novel functional materials and miniaturized devices for electronic and biomedical applications. Sensors, capacitors, actuators, displays, circuit boards, solar cells, electromagnetic shields and medical electrodes rely on flexible, electrically conductive layers or films. Scalable synthesis of such nanocomposite films, however, remains a challenge. Here, flame aerosol deposition of metallic nanosliver onto bare or polymer-coated glass substrates followed by polymer spin-coating on them leads to rapid synthesis of flexible, free-standing, electrically conductive nanocomposite films. Their electrical conductivity is determined during their preparation and depends on substrate composition and nanosilver deposition duration. Accordingly, thin (<500 nm) and flexible nanocomposite films are made having conductivity equivalent to metals (e.g. 5  × 10 4 S cm −1 ), even during repetitive bending. (paper)

  2. Mechanical and rheological response of polypropylene/boehmite nanocomposites

    CSIR Research Space (South Africa)

    Pedrazzoli, D

    2014-01-01

    Full Text Available In this work the influence of synthetic boehmite alumina (BA) nanoparticles with various surface treatments on the morphology, crystallization behavior and mechanical properties of polypropylene copolymer (PP) nanocomposites was studied...

  3. MWCNT/CdS hybrid nanocomposite for enhanced photocatalytic activity

    International Nuclear Information System (INIS)

    Chaudhary, Deepti; Khare, Neeraj; Vankar, V. D.

    2016-01-01

    Multi-walled carbon nanotubes (MWCNT)/CdS hybrid nanocomposite were synthesized by one step hydrothermal method. MWCNTs were used as a substrate for the growth of CdS nanoparticles. MWCNT/CdS nanocomposite and pure CdS were characterized by XRD, TEM, UV-vis and photoluminescence spectroscopy. HRTEM study confirms the intimate contact of CdS with MWCNT. The photocatalytic activity of nanocomposite was studied for the degradation of methylene blue dye under UV irradiation. The enhanced photocatalytic activity of MWCNT/CdS nanocomposite as compared to pure CdS has been attributed to reduced recombination of photogenerated charge carriers due to interfacial electron transfer from CdS to MWCNT.

  4. Synthesis of photothermal nanocomposites and their application to antibacterial assays

    Science.gov (United States)

    Yang, Ning; Wang, Chun; Wang, Xiaoyu; Li, Lidong

    2018-04-01

    In this work, we report a novel gold nanorod (AuNR)-based nanocomposite that shows strong binding to bacterium and high antibacterial efficiency. The AuNRs were used as a photothermal material to transform near-infrared radiation (NIR) into heat. We selected poly (acrylic acid) to modify the surface of the AuNRs based on a simple self-assembly method. After conjugation of the bacterium-binding molecule vancomycin, the nanocomposites were capable of efficiently gathering on the cell walls of bacteria. The nanocomposites exhibited a high bacterial inhibition capability owing to NIR-induced heat generation in situ. Therefore, the prepared photothermal nanocomposites show great potential for use in antibacterial assays.

  5. Development of Poly (Lactic Acid) Nanocomposite Films by Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Dadbin, Susan; Naimian, Faranak; Akhavan, Azam; Hasanpoor, Sorour [Radiation Application Research School, Nuclear Science and Research Institute, North Kargar Ave., Tehran (Iran, Islamic Republic of)

    2009-07-01

    Poly (lactic acid) and poly (lactic acid) -montmorillonite (MMT) nanocomposite films have been prepared by solvent casting method. Films were irradiated with 60Co radiation facility at various doses in the range of 5 to30 kGy. The effect of gamma irradiation on mechanical properties of neat PLA and nanocomposites is evaluated by the data obtained from tensile testing measurements. The degree of crosslinking is measured by gel content method. Thermal behavior of nanocomposites is studied by differential scanning calorimetry (DSC) and thermal gravimetry analysis (TGA). The morphology of the nanocomposites is characterized by transmission electron microscopy (TEM) and X ray diffraction. Structural changes in poly (lactic acid) are studied by Fourier transform infrared (FTIR). (author)

  6. Development of Poly (Lactic Acid) Nanocomposite Films by Ionizing Radiation

    International Nuclear Information System (INIS)

    Dadbin, Susan; Naimian, Faranak; Akhavan, Azam; Hasanpoor, Sorour

    2009-01-01

    Poly (lactic acid) and poly (lactic acid) -montmorillonite (MMT) nanocomposite films have been prepared by solvent casting method. Films were irradiated with 60Co radiation facility at various doses in the range of 5 to30 kGy. The effect of gamma irradiation on mechanical properties of neat PLA and nanocomposites is evaluated by the data obtained from tensile testing measurements. The degree of crosslinking is measured by gel content method. Thermal behavior of nanocomposites is studied by differential scanning calorimetry (DSC) and thermal gravimetry analysis (TGA). The morphology of the nanocomposites is characterized by transmission electron microscopy (TEM) and X ray diffraction. Structural changes in poly (lactic acid) are studied by Fourier transform infrared (FTIR). (author)

  7. Metal–carbon nanocomposites based on pyrolysed polyacrylonitrile

    Directory of Open Access Journals (Sweden)

    Irina A. Zaporotskova

    2015-06-01

    Full Text Available The electronic structure and geometry of metal−carbon nanocomposites based on pyrolyzed polyacrylonitrile (PPAN with Cu, Si, Fe, Co and Ni atoms using the DFT method have been theoretically studied. The effect of nitrogen on the stability of PPAN and its conductivity has been determined. The electrophysical properties and structure of metal nanocomposites have been studied using the XFA method. The composites have been produced by IR heating. We suggest that metal−carbon nanocomposites form due to the special processing of the (PAN−MeR samples. Metal nanoparticles are regularly dispersed in the nanocrystalline matrix of PPAN. The conductivity of these metal−carbon nanocomposites has an activation character and varies from 10−1 to 103 Om/cm depending on synthesis temperature (T=600–900 °С. The results of theoretical and experimental research are in a good agreement.

  8. Functionalized graphene sheet-Poly(vinylidene fluoride) conductive nanocomposites

    KAUST Repository

    Ansari, Seema; Giannelis, Emmanuel P.

    2009-01-01

    PVDF nanocomposites based on functionalized graphene sheets, FGS prepared from graphite oxide, and exfoliated graphite, EG, were prepared by solution processing and compression molding. FGS remains well dispersed in the PVDF composites as evidenced

  9. Hydrogen Storage Performance in Pd/Graphene Nanocomposites.

    Science.gov (United States)

    Zhou, Chunyu; Szpunar, Jerzy A

    2016-10-05

    We have developed a Pd-graphene nanocomposite for hydrogen storage. The spherically shaped Pd nanoparticles of 5-45 nm in size are homogeneously distributed over the graphene matrix. This new hydrogen storage system has favorable features like desirable hydrogen storage capacity, ambient conditions of hydrogen uptake, and low temperature of hydrogen release. At a hydrogen charging pressure of 50 bar, the material could yield a gravimetric density of 6.7 wt % in the 1% Pd/graphene nanocomposite. As we increased the applied pressure to 60 bar, the hydrogen uptake capacity reached 8.67 wt % in the 1% Pd/graphene nanocomposite and 7.16 wt % in the 5% Pd/graphene nanocomposite. This system allows storage of hydrogen in amounts that exceed the capacity of the gravimetric target announced by the U.S. Department of Energy (DOE).

  10. Ceramic Nanocomposites from Tailor-Made Preceramic Polymers

    Directory of Open Access Journals (Sweden)

    Gabriela Mera

    2015-04-01

    Full Text Available The present Review addresses current developments related to polymer-derived ceramic nanocomposites (PDC-NCs. Different classes of preceramic polymers are briefly introduced and their conversion into ceramic materials with adjustable phase compositions and microstructures is presented. Emphasis is set on discussing the intimate relationship between the chemistry and structural architecture of the precursor and the structural features and properties of the resulting ceramic nanocomposites. Various structural and functional properties of silicon-containing ceramic nanocomposites as well as different preparative strategies to achieve nano-scaled PDC-NC-based ordered structures are highlighted, based on selected ceramic nanocomposite systems. Furthermore, prospective applications of the PDC-NCs such as high-temperature stable materials for thermal protection systems, membranes for hot gas separation purposes, materials for heterogeneous catalysis, nano-confinement materials for hydrogen storage applications as well as anode materials for secondary ion batteries are introduced and discussed in detail.

  11. Ceramic Nanocomposites from Tailor-Made Preceramic Polymers.

    Science.gov (United States)

    Mera, Gabriela; Gallei, Markus; Bernard, Samuel; Ionescu, Emanuel

    2015-04-01

    The present Review addresses current developments related to polymer-derived ceramic nanocomposites (PDC-NCs). Different classes of preceramic polymers are briefly introduced and their conversion into ceramic materials with adjustable phase compositions and microstructures is presented. Emphasis is set on discussing the intimate relationship between the chemistry and structural architecture of the precursor and the structural features and properties of the resulting ceramic nanocomposites. Various structural and functional properties of silicon-containing ceramic nanocomposites as well as different preparative strategies to achieve nano-scaled PDC-NC-based ordered structures are highlighted, based on selected ceramic nanocomposite systems. Furthermore, prospective applications of the PDC-NCs such as high-temperature stable materials for thermal protection systems, membranes for hot gas separation purposes, materials for heterogeneous catalysis, nano-confinement materials for hydrogen storage applications as well as anode materials for secondary ion batteries are introduced and discussed in detail.

  12. Field emission study of MWCNT/conducting polymer nanocomposite

    Energy Technology Data Exchange (ETDEWEB)

    Alvi, M.A., E-mail: maalvee@yahoo.co.in [Department of Physics, King Abdulaziz University, Jeddah-21589 (Saudi Arabia); Al-Ghamdi, A.A. [Department of Physics, King Abdulaziz University, Jeddah-21589 (Saudi Arabia); Husain, M. [Department of Physics, Jamia Millia Islamia, New Delhi-110025 (India)

    2014-12-01

    MWCNTs/Polypyrrole nanocomposites were synthesized by solution mixing method. These synthesized nanocomposites were studied carefully by Raman Spectroscopy and Scanning Electron Microscopy measurements. The field emission study of MWCNTs/Polypyrrole nanocomposites were performed in diode arrangement under vacuum of the order of 10{sup −5} Torr. The emission current under exploration depends on applied voltage. The prepared nanocomposites depict low turn-on field at 1.4 V/μm that reaches to a maximum emission current density 0.020 mA/cm{sup 2} at 2.4 V/µm, which is calculated from the graph of current density (J) against the applied electric field (E) and from Fowler–Nordheim (F–N) plot.

  13. Permeation Behavior and Physical Properties of Natural Rubber Nanocomposites

    National Research Council Canada - National Science Library

    Zukas, Walter; Sennett, Michael; Welsh, Elizabeth; Rodriguez, Axel; Ziegler, David; Touchet, Paul

    2004-01-01

    .... A study was carried out to examine the effects of varying nanoparticle morphology and composition on the mechanical and barrier properties of polymer nanocomposites made with natural rubber (NR...

  14. NanoComposite Polymers for High Resolution Near Infrared Detectors

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop nanocomposite materials with tuned refractive index in the near infra red spectral range as an index-matched immersion lens for high resolution infra-red...

  15. Epoxy-silicate nanocomposites: Cure monitoring and characterization

    International Nuclear Information System (INIS)

    Hussain, Farzana; Chen, Jihua; Hojjati, Mehdi

    2007-01-01

    Epoxy-clay nanocomposites were prepared with organically modified layered clay with varying clay contents (1-8 wt.%). Neat resin and nanocomposite were characterized using different techniques. At first, the effect of nanoclay concentration on the cure behaviour was investigated using an on-line dielectric cure monitoring technique. Differential scanning calorimetry (DSC) was used to verify the dielectric measurement results. Furthermore, mechanical and thermal properties were studied using tensile test and Dynamic Mechanical Analysis (DMA), respectively. Experimental results showed that properties of the epoxy were changed evidently because of the nanoclay loading. The tensile modulus of the nanocomposites increased by 47%, however, no improvement in tensile strength and glass transition temperature (T g ) was observed. Fracture surface of the tensile samples were analyzed by Scanning Electron Microscope (SEM). The nanocomposites structures were characterized with Wide Angle X-Ray Diffraction (WAXD) and Transmission Electron Microscopy (TEM), which revealed the intercalated morphology of clay layers in the epoxy resin systems

  16. Synthesis of thermoresponsive poly(N-isopropylacrylamide)/clay nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.P.; Lyu, S.G. [Yeungnam Univeristy, Kyongsan (Korea); Bae, K.S. [Andong Institute of Information and Technology, Andong (Korea); Sur, G.S. [Yeungnam Univeristy, Kyungsan (Korea)

    2001-03-01

    MAPTAC-MMT was prepared by exchanging the mineral cation (sodium montmorillonite) with 3-(methacryloyl amino) propyltrimethyl ammonium chloride, thus rendering the mineral organophilic and forming polymerizable moieties directly bonded to the surface of montmorillonite (MMT). Thermoresponsive nanocomposites (PNIPAM-MMT) were synthesized by polymerization of N-isopropyl acrylamide in an aqueous suspension of MAPTAC-MMT at room temperature. Thermoresponsive nanocomposites exhibited a low critical solution temperature (LCST) similar to unmodified poly(N-isopropyl acrylamide) (PNIPAM). The LCST of thermoresponsive nanocomposites decreased in proportion to the amount of MAPTAC-MMT. TGA results showed that the thermal stability of thermoresponsieve nanocomposites was improved compared to PNIPAM itself the thermoresponsive polymer. (author). 25 refs., 9 figs.

  17. Nafion–clay nanocomposite membranes: Morphology and properties

    KAUST Repository

    Herrera Alonso, Rafael; Estevez, Luis; Lian, Huiqin; Kelarakis, Antonios; Giannelis, Emmanuel P.

    2009-01-01

    A series of Nafion-clay nanocomposite membranes were synthesized and characterized. To minimize any adverse effects on ionic conductivity the clay nanoparticles were H+ exchanged prior to mixing with Nafion. Well-dispersed, mechanically robust, free-standing nanocomposite membranes were prepared by casting from a water suspension at 180 °C under pressure. SAXS profiles reveal a preferential orientation of Nafion aggregates parallel to the membrane surface, or normal plane. This preferred orientation is induced by the platy nature of the clay nanoparticles, which tend to align parallel to the surface of the membrane. The nanocomposite membranes show dramatically reduced methanol permeability, while maintaining high levels of proton conductivity. The hybrid films are much stiffer and can withstand much higher temperatures compared to pure Nafion. The superior thermomechanical, electrochemical and barrier properties of the nanocomposite membranes are of significant interest for direct methanol fuel cell applications. © 2009 Elsevier Ltd. All rights reserved.

  18. Ziegler-Natta catalyst for polypropylene and polyethylene nanocomposites preparation

    International Nuclear Information System (INIS)

    Silvino, Alexandre C.; Dias, Marcos L.; Bezerra, Ana Beatriz F.

    2009-01-01

    Polypropylene and polyethylene nanocomposites are well known for their improved properties when compared with the neat polymers. In this work we report the preparation, characterization and the activity studies of a fourth generation Ziegler-Natta catalyst for the preparation of polyolefin/clay nanocomposites. The catalyst was prepared treating an organo-modified silicate with magnesium and titanium compounds. The content of titanium and that of the magnesium of the catalyst were determined by UV-vis spectroscopy and atomic absorption respectively. The first results show that the catalyst is active for propylene polymerization being suitable for polypropylene/clay nanocomposite preparation. The catalyst activity for ethylene polymerization was also investigated. The X-ray diffraction patterns of the polyethylene samples suggest the clay exfoliation occurs in the in situ polymerization, even with high clay loading (about 9 %) indicating that a nanocomposite was formed. (author)

  19. Polymer nanocomposite processing, characterization, and applications 2012 (Editorial)

    CSIR Research Space (South Africa)

    Mago, G

    2012-12-01

    Full Text Available Polymer nanocomposites have attracted interest in the last few decades providing scope for improvement of various functional properties, such as mechanical, thermal, optical, rheological, magnetic, and electrical. The improvements in functional...

  20. Photocatalytic Activity of Graphene/ZnO Nanocomposite Fabricated ...

    Indian Academy of Sciences (India)

    method to fabricate graphene-metal oxide nanocomposites which could lead to various ... TiO2 and ZnO are two remarkable nanoparticles be- ..... available at www.ias.ac.in/chemsci. ... Design, Synthesis, and Characterization of Graphene−.

  1. Novel dental nanocomposites: Fabrication, and investigation of their ...

    Indian Academy of Sciences (India)

    56

    To the best of our knowledge, research on design and development of dendritic and antibacterial .... and purified according to the standard methods. 2.2. Nanocomposite ... The composite was further mixed manually for about 20 minutes, and.

  2. Nafion–clay nanocomposite membranes: Morphology and properties

    KAUST Repository

    Herrera Alonso, Rafael

    2009-05-01

    A series of Nafion-clay nanocomposite membranes were synthesized and characterized. To minimize any adverse effects on ionic conductivity the clay nanoparticles were H+ exchanged prior to mixing with Nafion. Well-dispersed, mechanically robust, free-standing nanocomposite membranes were prepared by casting from a water suspension at 180 °C under pressure. SAXS profiles reveal a preferential orientation of Nafion aggregates parallel to the membrane surface, or normal plane. This preferred orientation is induced by the platy nature of the clay nanoparticles, which tend to align parallel to the surface of the membrane. The nanocomposite membranes show dramatically reduced methanol permeability, while maintaining high levels of proton conductivity. The hybrid films are much stiffer and can withstand much higher temperatures compared to pure Nafion. The superior thermomechanical, electrochemical and barrier properties of the nanocomposite membranes are of significant interest for direct methanol fuel cell applications. © 2009 Elsevier Ltd. All rights reserved.

  3. Ceramic Nanocomposites from Tailor-Made Preceramic Polymers

    Science.gov (United States)

    Mera, Gabriela; Gallei, Markus; Bernard, Samuel; Ionescu, Emanuel

    2015-01-01

    The present Review addresses current developments related to polymer-derived ceramic nanocomposites (PDC-NCs). Different classes of preceramic polymers are briefly introduced and their conversion into ceramic materials with adjustable phase compositions and microstructures is presented. Emphasis is set on discussing the intimate relationship between the chemistry and structural architecture of the precursor and the structural features and properties of the resulting ceramic nanocomposites. Various structural and functional properties of silicon-containing ceramic nanocomposites as well as different preparative strategies to achieve nano-scaled PDC-NC-based ordered structures are highlighted, based on selected ceramic nanocomposite systems. Furthermore, prospective applications of the PDC-NCs such as high-temperature stable materials for thermal protection systems, membranes for hot gas separation purposes, materials for heterogeneous catalysis, nano-confinement materials for hydrogen storage applications as well as anode materials for secondary ion batteries are introduced and discussed in detail. PMID:28347023

  4. Nanocomposites formed by ion implantation: Recent developments and future opportunities

    International Nuclear Information System (INIS)

    Meldrum, A.; Boatner, L.A.; White, C.W.

    2001-01-01

    Ion implantation is a versatile and powerful technique for forming many types of nanocrystalline precipitates embedded in the near-surface region of a wide variety of crystalline and amorphous host materials. The unique optical, electronic and magnetic properties of these nanocomposites has stimulated considerable recent research interest. In this review, we discuss recent developments in the field as well as some of the problems that currently hinder the potential applications of nanocomposites formed by ion implantation

  5. Influence of Two Compatibilizers on Clay/PP Nanocomposites Properties

    DEFF Research Database (Denmark)

    Potarniche, Catalina-Gabriela; Vuluga, Zina; Christiansen, Jesper de Claville

    2013-01-01

    -screw extruder was used to obtain nanocomposites based on polypropylene via the melt intercalation technique. X-ray diffraction and differential scanning calorimetric results showed that intercalated nanocomposites with improved thermal stability were obtained. Increases of 8% in tensile strength, 34% in modulus......, and 20% in crystallinity were observed. Also an increase of 23% in creep properties was observed when using these two compatibilizer system and 1% clay. POLYM. ENG. SCI., 00:000–000, 2012. ª2012 Society of Plastics Engineers...

  6. Functional Block Copolymers as Compatibilizers for Nanoclays in Polypropylene Nanocomposites

    DEFF Research Database (Denmark)

    Jankova Atanasova, Katja; Daugaard, Anders Egede; Stribeck, Norbert

    2011-01-01

    With the aim of creating tough nanocomposits (NC) [1] based on polypropylene (PP) and nanoclay (NCl) in the framework of the 7th EU program NANOTOUGH we have designed amphiphilic block copolymers utilizing Atom Transfer Radical Polymerization (ATRP) [2]. They consist of a hydrophobic block...... crystallites) is replaced by alien-reinforcement (of the MMT). Furthermore, the results from the impact strength and cyclic test of the prepared PP nanocomposites [3] are promicing....

  7. Conjugated polymer/graphene oxide nanocomposite as thermistor

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Girish M., E-mail: varadgm@gmail.com; Deshmukh, Kalim [Polymer Nanocomposite Laboratory, Material Physics Division, School of Advanced Sciences, VIT University, Vellore - 632014, TN (India)

    2015-06-24

    We demonstrated the synthesis and measurement of temperature dependent electrical resistivity of graphene oxide (GO) reinforced poly (3, 4 - ethylenedioxythiophene) - tetramethacrylate (PEDOTTMA)/Polymethylmethacrylate (PMMA) based nanocomposites. Negative temperature coefficient (NTC) was observed for 0.5, 1 % GO loading and the positive temperature coefficient (PTC) was observed for 1.5 and 2 % Go loading in the temperature (40 to 120 °C). The GO inducted nanocomposite perform as an excellent thermistor and suitable for electronic and sensor domain.

  8. Conjugated polymer/graphene oxide nanocomposite as thermistor

    International Nuclear Information System (INIS)

    Joshi, Girish M.; Deshmukh, Kalim

    2015-01-01

    We demonstrated the synthesis and measurement of temperature dependent electrical resistivity of graphene oxide (GO) reinforced poly (3, 4 - ethylenedioxythiophene) - tetramethacrylate (PEDOTTMA)/Polymethylmethacrylate (PMMA) based nanocomposites. Negative temperature coefficient (NTC) was observed for 0.5, 1 % GO loading and the positive temperature coefficient (PTC) was observed for 1.5 and 2 % Go loading in the temperature (40 to 120 °C). The GO inducted nanocomposite perform as an excellent thermistor and suitable for electronic and sensor domain

  9. Processing-structure-properties relationships in PLA nanocomposite films

    Science.gov (United States)

    Di Maio, L.; Scarfato, P.; Garofalo, E.; Galdi, M. R.; D'Arienzo, L.; Incarnato, L.

    2014-05-01

    This work deals on the possibility to improve performances of PLA-based nanocomposite films, for packaging applications, through conveniently tuning materials and processing conditions in melt compounding technology. In particular, two types of polylactic acid and different types of filler selected from montmorillonites and bentonites families were used to prepare the hybrid systems by using a twin-screw extruder. The effect of biaxial drawing on morphology and properties of the nanocomposites, produced by film blowing, was investigated.

  10. Microfibrillated cellulose and new nanocomposite materials: a review

    DEFF Research Database (Denmark)

    Siró, Istvan; Plackett, David

    2010-01-01

    Due to their abundance, high strength and stiffness, low weight and biodegradability, nano-scale cellulose fiber materials (e.g., microfibrillated cellulose and bacterial cellulose) serve as promising candidates for bio-nanocomposite production. Such new high-value materials are the subject...... in order to address this hurdle. This review summarizes progress in nanocellulose preparation with a particular focus on microfibrillated cellulose and also discusses recent developments in bio-nanocomposite fabrication based on nanocellulose....

  11. Ceramic Nanocomposites from Tailor-Made Preceramic Polymers

    OpenAIRE

    Mera, Gabriela; Gallei, Markus; Bernard, Samuel; Ionescu, Emanuel

    2015-01-01

    The present Review addresses current developments related to polymer-derived ceramic nanocomposites (PDC-NCs). Different classes of preceramic polymers are briefly introduced and their conversion into ceramic materials with adjustable phase compositions and microstructures is presented. Emphasis is set on discussing the intimate relationship between the chemistry and structural architecture of the precursor and the structural features and properties of the resulting ceramic nanocomposites. Va...

  12. Exploring release and recovery of nanomaterials from commercial polymeric nanocomposites

    International Nuclear Information System (INIS)

    Busquets-Fité, Martí; Puntes, Víctor; Fernandez, Elisabet; Janer, Gemma; Vilar, Gemma; Vázquez-Campos, Socorro; Zanasca, R; Citterio, C; Mercante, L

    2013-01-01

    Much concern has been raised about the risks associated with the broad use of polymers containing nanomaterials. Much is known about degradation and aging of polymers and nanomaterials independently, but very few studies have been done in order to understand degradation of polymeric nanocomposites containing nanomaterials and the fate of these nanomaterials, which may occur in suffering many processes such as migration, release and physicochemical modifications. Throughout the UE funded FP7 project NANOPOLYTOX, studies on the migration, release and alteration of mechanical properties of commercial nanocomposites due to ageing and weathering have been performed along with studies on the feasibility of recovery and recycling of the nanomaterials. The project includes the use as model nanocomposites of Polyamide-6 (PA), Polypropylene (PP) and Ethyl Vinyl Acetate (EVA) as polymeric matrix filled with a 3% in mass of a set of selected broadly used nanomaterials; from inorganic metal oxides nanoparticles (SiO2, TiO2 and ZnO) to multi-walled carbon nanotubes (MWCNT) and Nanoclays. These model nanocomposites were then treated under accelerated ageing conditions in climatic chamber. To determine the degree of degradation of the whole nanocomposite and possible processes of migration, release and modification of the nanofillers, nanocomposites were characterized by different techniques. Additionally, recovery of the nanomaterials fro m the polymeric matrix was addressed, being successfully achieved for PA and PP based nanocomposites. In the case of PA, dissolution of the polymeric matrix using formic acid and further centrifugation steps was the chosen approach, while for PP based nanocomposites calcination was performed.

  13. Polyethylenedioxythiophene and molybdenum disulfide nanocomposite electrodes for supercapacitor applications

    International Nuclear Information System (INIS)

    Alamro, Turki; Ram, Manoj K.

    2017-01-01

    Highlights: • MoS_2-PEDOT nanocomposite electrode material was synthesized using polyanion ‘PSS’ and surfactant CTAB in an aqueous media. • The supercapacitor based on composite MoS_2-PEDOT electrode revealed higher energy density than graphene composite electrodes. • The specific capacitance of 361 Farad/gram (F/g) was obtained for 1:2 weight ratio of MoS2 to the EDOT monomer in MoS_2-PEDOT nanocomposite based electrodes. - Abstract: An innovative nanocomposite electrode was chemically synthesized using molybdenum disulphide (MoS_2)- polyethylenedioxythiophene (PEDOT) to understand the charge mechanism in a symmetric supercapacitor. The MoS_2-PEDOT nanocomposite was produced at various ratios of MoS_2 to ethylenedioxythiophene (EDOT) in an aqueous medium of polyanions polystyrene sulfonate (PSS) and cetyltrimethylammonium bromide (CTAB) at controlled conditions. The morphology, crystallinity, and optical properties of MoS_2-PEDOT nanocomposite materials were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, particle size analyzer, Raman spectroscopy, X-ray-diffraction, and transmission electron microscopy (TEM) techniques, respectively. The electrochemical properties of the supercapacitor were investigated using cyclic voltammetry, charging–discharging at constant current and electrochemical impedance spectroscopy (EIS) techniques. The specific capacitance, power and energy densities of the supercapacitor were estimated using cyclic voltammetry (CV), charging–discharging, Nyquist and Bode plots. The specific capacitance was estimated to be 361 Farad/gram (F/g) for the 1:2 weight ratio of MoS_2 to the EDOT monomer in the MoS_2-PEDOT nanocomposite based electrodes. Nevertheless, this study provides a fundamental aspect of synthesis of nanocomposite material for optimum attainment supercapacitive properties based on the MoS_2-PEDOT nanocomposite electrode for practical energy storage applications.

  14. Antibacterial performance of bovine lactoferrin-fish gelatine electrospun nanocomposites

    OpenAIRE

    Padrão, Jorge; Machado, Raul; Casal, Margarida; Rodrigues, L. R.; Dourado, Fernando; Lanceros-Méndez, S.; Sencadas, V.

    2014-01-01

    Antibacterial performance of bovine lactoferrin-fish gelatine electrospun nanocomposites The alarming increase of antibiotic resistant microorganisms urged the development and synthesis of novel antimicrobial biomaterials, to be employed in a broad range of applications, ranging from food casings to medical devices [1 – 3]. This work describes the processing and characterization of an innovative fully biobased eletrctrospun nanocomposite material displaying antibacterial properties. Its c...

  15. Corrosion Protection of Steel by Epoxy-Organoclay Nanocomposite Coatings

    OpenAIRE

    Domna Merachtsaki; Panagiotis Xidas; Panagiotis Giannakoudakis; Konstantinos Triantafyllidis; Panagiotis Spathis

    2017-01-01

    The purpose of the present work was to study the corrosion behavior of steel coated with epoxy-(organo) clay nanocomposite films. The investigation was carried out using salt spray exposures, optical and scanning electron microscopy examination, open circuit potential, and electrochemical impedance measurements. The mechanical, thermomechanical, and barrier properties of pristine glassy epoxy polymer and epoxy-clay nanocomposites were examined. The degree of intercalation/exfoliation of clay ...

  16. Polypropylene/graphite nanocomposites by in situ polymerization

    International Nuclear Information System (INIS)

    Milani, Marceo A.; Galland, Giselda B.; Quijada, Raul

    2011-01-01

    This work presents the synthesis of nanocomposites of polypropylene/graphite by in situ polymerization using metallocene catalyst and graphene nanosheets. Initially was analyzed which of the metallocene catalysts rac-Et(Ind) 2 ZrCl 2 or rac-Me 2 Si(Ind) 2 ZrCl 2 produces polypropylene with mechanical properties more relevant. Then it were performed the in situ polymerization reactions to obtain the nanocomposites. The polymeric materials were characterized by XRD, DSC, GPC and DMTA. (author)

  17. Study of the effects of additives on structural properties of the Ba{sub x}Sr{sub 1-x}Fe{sub 12}O{sub 19} hexaferrite; Estudo do efeito de aditivos nas propriedades estruturais da hexaferrita Ba{sub x}Sr{sub 1-x}Fe{sub 12}O{sub 19}

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Y.S.; Pereira, C.A.; Farias, F.C.; Mello, P.S.; Alves, A.G.; Pereira, F.M.; Barroso, M.B., E-mail: yuri.link2@gmail.com [Universidade Federal do Cariri (UFCA), Juazeiro do Norte, CE (Brazil); Saraiva, I.R.; Conde, W.S. [DeVry Fanor, Fortaleza, CE (Brazil); Sombra, A.B. [Laboratorio de Telecomunicacoes e Ciencia e Engenharia de Materiais (LOCEM/UFC), Fortaleza, CE (Brazil)

    2016-07-01

    The Hexaferrites are magnetic ceramic materials chemically and thermally stable, low-cost and easy processing. The objective of this work was to study the effects of SiO2 and CaO additives on structural properties of hexaferrite Ba{sub x}Sr{sub 1-x}Fe{sub 12}O{sub 19}. The samples were characterized by scanning electron microscopy (SEM), X-Ray Diffraction (XRD) and quantified by the Rietveld method. The doped samples showed no structural change. With the concentration of dopant employed, there was a decrease in the sintering temperature of all samples Ba{sub x}Sr{sub 1-x}Fe{sub 12}O{sub 19} 1100 °C/5h to 1000 °C/2h. After addition of dopants, it was observed that the growth of the grains in the samples did not occur uniformly. This uneven growth can is being influenced by the concentrations of Ba and Sr atoms present in the samples, as well as some sort of reaction with the dopant elements. (author)

  18. Electrically and Thermally Conducting Nanocomposites for Electronic Applications

    Directory of Open Access Journals (Sweden)

    Daryl Santos

    2010-02-01

    Full Text Available Nanocomposites made up of polymer matrices and carbon nanotubes are a class of advanced materials with great application potential in electronics packaging. Nanocomposites with carbon nanotubes as fillers have been designed with the aim of exploiting the high thermal, electrical and mechanical properties characteristic of carbon nanotubes. Heat dissipation in electronic devices requires interface materials with high thermal conductivity. Here, current developments and challenges in the application of nanotubes as fillers in polymer matrices are explored. The blending together of nanotubes and polymers result in what are known as nanocomposites. Among the most pressing current issues related to nanocomposite fabrication are (i dispersion of carbon nanotubes in the polymer host, (ii carbon nanotube-polymer interaction and the nature of the interface, and (iii alignment of carbon nanotubes in a polymer matrix. These issues are believed to be directly related to the electrical and thermal performance of nanocomposites. The recent progress in the fabrication of nanocomposites with carbon nanotubes as fillers and their potential application in electronics packaging as thermal interface materials is also reported.

  19. Preparation and fluorescence properties of 6-carboxyfluorescein/hydrotalcite nanocomposites

    International Nuclear Information System (INIS)

    Li, Chunfang; Qi, Yanhai; Li, Qianru; Li, Dongxiang; Hou, Wanguo

    2014-01-01

    The nanocomposites of fluorescent dye/hydrotalcite-like compounds (HTlc) synthesized by intercalation and/or surface adsorption methods have exhibited specific photophysical and photochemical property. In this work, 6-carboxyfluorescein (6CF)/HTlc nanocomposites were synthesized by ammonia coprecipitation and reconstruction-induced surface adsorption methods, and they were characterized by powder X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Thermogravimetric differential thermal measurements (TG-DTA) and fluorescence spectra. The results demonstrate that the dye molecules are primarily adsorbed on HTlc surface. The fluorescence emission of 6CF/Mg–Al HTlc composites is related with 6CF dosage due to the self-quenching mechanism. The 6CF/Zn–Al HTlc nanocomposite reconstructed at high temperature have much strong luminescence than that reconstructed at room temperature and the 6CF/Mg–Al HTlc nanocomposites. -- Highlights: • Fluorescent 6-carboxyfluorescein/HTlc nanocomposites were synthesized. • Fluorescent dye molecules are primarily adsorbed on HTlc surface. • Nanocomposite luminescence is related with the cluster structure of fluorescent dyes

  20. Synthesis of PDLLA/PLLA-bentonite nanocomposite through sonication

    International Nuclear Information System (INIS)

    Sitompul, Johnner; Setyawan, Daru; Kim, Daniel Young Joon; Lee, Hyung Woo

    2016-01-01

    This paper concerns the synthesis of poly(D,L-lactic acid)/poly(L-lactic acid) bentonite nanocomposites. Poly (D,L-lactic acid) (PDLLA) was synthesized using lactic acid through the ZnO-catalyzed direct polycondensation method at vacuum pressure and poly(L-lactic acid) (PLLA) was synthesized with L-lactide by ring-opening polymerization method. The PDLLA/PLLA-bentonite nanocomposite films were synthesized using the solvent casting method. The nanoclay, bentonite, was prepared using the solution-intercalation method by dissolving the nanoparticles into chloroform before sonication. In this study, PDLLA/PLLA-bentonite nanocomposite films were produced using variable amounts of nanoclay and sonication times during the mixing of PDLLA/PLLA and bentonite. The properties of the PDLLA/PLLA nanocomposites were then characterized using the X-ray Diffraction (XRD), Universal Testing Machine (UTM), Water Vapor Permeability (WVP) tests, and the enzymatic biodegradability test. The XRD test was used to measure the intercalation of nanoclay layers in the PDLLA/PLLA matrix and the PDLLA/PLLA-bentonite intercalated nanocomposite films. It was found through these various tests that adding bentonite to the PDLLA/PLLA increases tensile strength to 56.76 MP. Furthermore, the biodegradability increases as well as the barrier properties of the polymers The different sonication time used during the mixing of the polymer solution with bentonite also affected the properties of the PDLLA/PLLA-bentonite nanocomposite films.

  1. Polymer-Layered Silicate Nanocomposites for Cryotank Applications

    Science.gov (United States)

    Miller, Sandi G.; Meador, Michael A.

    2007-01-01

    Previous composite cryotank designs have relied on the use of conventional composite materials to reduce microcracking and permeability. However, revolutionary advances in nanotechnology derived materials may enable the production of ultra-lightweight cryotanks with significantly enhanced durability and damage tolerance, as well as reduced propellant permeability. Layered silicate nanocomposites are especially attractive in cryogenic storage tanks based on results that have been reported for epoxy nanocomposite systems. These materials often exhibit an order of magnitude reduction in gas permeability when compared to the base resin. In addition, polymer-silicate nanocomposites have been shown to yield improved dimensional stability, strength, and toughness. The enhancement in material performance of these systems occurs without property trade-offs which are often observed in conventionally filled polymer composites. Research efforts at NASA Glenn Research Center have led to the development of epoxy-clay nanocomposites with 70% lower hydrogen permeability than the base epoxy resin. Filament wound carbon fiber reinforced tanks made with this nanocomposite had a five-fold lower helium leak rate than the corresponding tanks made without clay. The pronounced reduction observed with the tank may be due to flow induced alignment of the clay layers during processing. Additionally, the nanocomposites showed CTE reductions of up to 30%, as well as a 100% increase in toughness.

  2. Investigation of optical properties of Ag: PMMA nanocomposite structures

    Science.gov (United States)

    Ponelyte, S.; Palevicius, A.; Guobiene, A.; Puiso, J.; Prosycevas, I.

    2010-05-01

    In the recent years fundamental research involving the nanodimensional materials has received enormous momentum for observing and understanding new types of plasmonic materials and their physical phenomena occurring in the nanoscale. Mechanical and optical properties of these polymer based nanocomposite structures depend not only on type, dimensions and concentration of filler material, but also on a kind of polymer matrix used. By proper selection of polymer matrix and nanofillers, it is possible to engineer nanocomposite materials with certain favorable properties. One of the most striking features of nanocomposite materials is that they can expose unique optical properties that are not intrinsic to natural materials. In these researches, nanocomposite structures were formed using polymer (PMMA) as a matrix, and silver nanoparticles as fillers. By hot embossing procedure a diffraction grating was imprinted on formed layers. The effect of UV exposure time on nanocomposite structures morphology, optical (diffraction effectiveness, absorbance) and mechanical properties was investigated. Results were confirmed by UV-VIS spectrometer, Laser Diffractometer, PMT- 3 and AFM. Investigations proposed new nanocomposite structures as plasmonic materials with improved optical and mechanical properties, which may be applied for a number of technological applications: micro-electro-mechanical devices, optical devices, various plasmonic sensors, or even in DNA nanotechnology.

  3. Synthesis of PDLLA/PLLA-bentonite nanocomposite through sonication

    Energy Technology Data Exchange (ETDEWEB)

    Sitompul, Johnner, E-mail: sitompul@che.itb.ac.id; Setyawan, Daru, E-mail: daru.setyawan@gmail.com; Kim, Daniel Young Joon, E-mail: daniel.kim12321@gmail.com [Department of Chemical Engineering, Faculty of Industrial Technology, Institute of Technology Bandung Jl. Ganesha 10, Bandung, West Java, 40132 (Indonesia); Lee, Hyung Woo, E-mail: leehw@che.itb.ac.id [Department of Chemical Engineering, Faculty of Industrial Technology, Institute of Technology Bandung Jl. Ganesha 10, Bandung, West Java, 40132 (Indonesia); Research and Business Foundation, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi, 440-746 (Korea, Republic of)

    2016-04-19

    This paper concerns the synthesis of poly(D,L-lactic acid)/poly(L-lactic acid) bentonite nanocomposites. Poly (D,L-lactic acid) (PDLLA) was synthesized using lactic acid through the ZnO-catalyzed direct polycondensation method at vacuum pressure and poly(L-lactic acid) (PLLA) was synthesized with L-lactide by ring-opening polymerization method. The PDLLA/PLLA-bentonite nanocomposite films were synthesized using the solvent casting method. The nanoclay, bentonite, was prepared using the solution-intercalation method by dissolving the nanoparticles into chloroform before sonication. In this study, PDLLA/PLLA-bentonite nanocomposite films were produced using variable amounts of nanoclay and sonication times during the mixing of PDLLA/PLLA and bentonite. The properties of the PDLLA/PLLA nanocomposites were then characterized using the X-ray Diffraction (XRD), Universal Testing Machine (UTM), Water Vapor Permeability (WVP) tests, and the enzymatic biodegradability test. The XRD test was used to measure the intercalation of nanoclay layers in the PDLLA/PLLA matrix and the PDLLA/PLLA-bentonite intercalated nanocomposite films. It was found through these various tests that adding bentonite to the PDLLA/PLLA increases tensile strength to 56.76 MP. Furthermore, the biodegradability increases as well as the barrier properties of the polymers The different sonication time used during the mixing of the polymer solution with bentonite also affected the properties of the PDLLA/PLLA-bentonite nanocomposite films.

  4. Polymer-ceramic nanocomposites for applications in the bone surgery

    International Nuclear Information System (INIS)

    Stodolak, E; Gadomska, K; Lacz, A; Bogun, M

    2009-01-01

    The subject of this work was preparation and investigation of properties of a nanocomposite material based on polymer matrix modified with nanometric silica particles (SiO 2 ). The composite matrix consisted of resorbable P(L/DL)LA polymer with certified biocompatibility. Nanometric silica was introduced into the matrix by means of ultrasonic homogenisation and/or mechanical stirring. The silica was introduced directly e.g. as nanoparticles or inside calcium alginate fibres which contained 3 wt.% of amorphous SiO 2 . Proper dispersion of nano-filliers was confirmed by means of thermal analysis (TG/DTA, DSC). It was observed, that the presence of inorganic nanoparticles influenced several surface parameters of the nanocomposites i.e. hydrophility (a decrease of surface energy) and topography (both in micro- and nano-scale). Additionally, the nanocomposites exhibited enhanced mechanical properties (Young's modulus, tensile strength) compared to the pure polymer. The nanocomposites were bioactive materials (SBF/3 days/37 deg. C). Biological tests (MTT test) showed a good viability of human osteoblasts (hFOB 1.19) in contact with the nanocomposites surface. Results of preliminary biological tests carried out with the use of mother cells extracted from human bone marrow showed that the nanocomposites may provide differenation of bone cells.

  5. Graphene nanocomposites as thermal interface materials for cooling energy devices

    Science.gov (United States)

    Dmitriev, A. S.; Valeev, A. R.

    2017-11-01

    The paper describes the technology of creating samples of graphene nanocomposites based on graphene flakes obtained by splitting graphite with ultrasound of high power. Graphene nanocomposites in the form of samples are made by the technology of weak sintering at high pressure (200-300 bar) and temperature up to 150 0 C, and also in the form of compositions with polymer matrices. The reflection spectra in the visible range and the near infrared range for the surface of nanocomposite samples are studied, the data of optical and electronic spectroscopy of such samples are givenIn addition, data on the electrophysical and thermal properties of the nanocomposites obtained are presented. Some analytical models of wetting and spreading over graphene nanocomposite surfaces have been constructed and calculated, and their effective thermal conductivity has been calculated and compared with the available experimental data. Possible applications of graphene nanocomposites for use as thermal interface materials for heat removal and cooling for power equipment, as well as microelectronics and optoelectronics devices are described.

  6. Structure and mechanical properties of polyamide 6/Brazilian clay nanocomposites

    Directory of Open Access Journals (Sweden)

    Amanda Melissa Damião Leite

    2009-06-01

    Full Text Available Recent interest in polymer/organoclays nanocomposites systems is motivated by the possibility of achieving enhanced properties and added functionality at lower clay loading as compared to conventional micron size fillers. By adding montmorillonite clay to polyamide 6 increases the Young modulus, yield strength and also improves barrier properties. In this work, nanocomposites of polyamide 6 with montmorillonite clay were obtained. The clay was chemically modified with three different quaternary ammonium salts such as: Dodigen, Genamin and Cetremide. In this case, a dispersion of Na-MMT was stirred and a salt equivalent to 1:1 of cation exchange capacity (CEC of Na-MMT was added to the dispersion. The montmorillonite clay (untreated and treated by ammonium salts and nanocomposites were characterized by X ray diffractions. Also the nanocomposites were characterized by transmission electron microscopy and mechanical properties. The results indicated that all the quaternary ammonium salts were intercalated between the layers of clay, leading to an expansion of the interlayer spacing. The obtained nanocomposites showed better mechanical properties when compared to polyamide 6. The clay acted as reinforcing filler, increasing the rigidity of nanocomposites and decreasing its ductility.

  7. Preparation and Characteristics of Biodegradable Polyurethane/Clay Nanocomposite Films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Woo [Kyonggi University, Suwon (Korea, Republic of)

    2013-06-15

    Biodegradable polyurethane (PU)/clay nanocomposite films were prepared via extrusion compounding process followed by casting film process. Organically modified montmorillonite (denoted as C30B) with a large amount of hydroxyl groups on its surface was used for the formation of strong bonding with PU resin. From both XRD analysis and TEM observations, the intercalated and exfoliated structure, and dispersion state of silicate platelets in the compounded nanocomposite films were confirmed. In addition, the rheological and tensile properties, optical transparency, oxygen permeability of the prepared nanocomposites were investigated as a function of added nanoclay content, and moreover based on these results, the correlation between the morphology and the resulting properties of the nanocomposites could be presented. The inclusion of nanoclays at appropriate content resulted in remarkable improvement in the nanocomposite performance including tensile modulus, elongation, transparency, and oxygen barrier property, however at excess amount of nanoclays, reduction or very slight increase was observed due to poor dispersion. The biodegradability of the prepared nanocomposite film was evaluated by examining the deterioration in the barrier and tensile properties during degradation period under compost.

  8. Preparation and Characterization of Phenolic Resin/Montmorillonite Nanocomposite

    Directory of Open Access Journals (Sweden)

    Morteza Soltan-Dehghan

    2012-12-01

    Full Text Available Phenolic resins have been widely used for selective high technology applications due to their excellent ablative properties, structural integrity and thermal stability that make them appropriate for thermal insulation materials, wood products industry, coatings, moulding compounds and composite materials. Polymer layered silicate nanocomposites based on montmorillonite (MMT have attracted a great deal of attention because of enhanced properties in mechanical, thermal, barrier and clarity properties without a significant increase in density, which is not possible with conventional fillers. Phenolic resin/montmorillonite (Cloisite 15A nanocomposite was prepared by a combined route of solution blending and in-situ polymerization. Theoptimized conditions for preparation of nanocomposite were achieved by evaluation of various processing parameters (mechanical mixer, high speed disperser and high energy ultrasonic source, mixing time (0.5, 1, 3, 10, 24, 48, 72, and 96 h and different amounts of montmorillonite (5 and 10 weight percents of montmorillonite relative to resol. X-Ray Diffractometer and thermal gravimetric analyzer were used accordingly to show the degree of nanodispersions of organomontmorillonite in polymeric matrix and the effect of nanofiller on thermal stability of nanocomposite with respect to neatresol. The results of high energy ultrasonic source show that a nanocomposite of phenolic resin with 5 wt% montmorillonite displays the best dispersion of clay layers. Thermal stability of nanocomposite was increased by 27% in comparison with neat resol.

  9. Polymer-ceramic nanocomposites for applications in the bone surgery

    Science.gov (United States)

    Stodolak, E.; Gadomska, K.; Lacz, A.; Bogun, M.

    2009-01-01

    The subject of this work was preparation and investigation of properties of a nanocomposite material based on polymer matrix modified with nanometric silica particles (SiO2). The composite matrix consisted of resorbable P(L/DL)LA polymer with certified biocompatibility. Nanometric silica was introduced into the matrix by means of ultrasonic homogenisation and/or mechanical stirring. The silica was introduced directly e.g. as nanoparticles or inside calcium alginate fibres which contained 3 wt.% of amorphous SiO2. Proper dispersion of nano-filliers was confirmed by means of thermal analysis (TG/DTA, DSC). It was observed, that the presence of inorganic nanoparticles influenced several surface parameters of the nanocomposites i.e. hydrophility (a decrease of surface energy) and topography (both in micro- and nano-scale). Additionally, the nanocomposites exhibited enhanced mechanical properties (Young's modulus, tensile strength) compared to the pure polymer. The nanocomposites were bioactive materials (SBF/3 days/37oC). Biological tests (MTT test) showed a good viability of human osteoblasts (hFOB 1.19) in contact with the nanocomposites surface. Results of preliminary biological tests carried out with the use of mother cells extracted from human bone marrow showed that the nanocomposites may provide differenation of bone cells.

  10. Preparation, Characterization, and Modeling of Carbon Nanofiber/Epoxy Nanocomposites

    Directory of Open Access Journals (Sweden)

    Lan-Hui Sun

    2011-01-01

    Full Text Available There is a lack of systematic investigations on both mechanical and electrical properties of carbon nanofiber (CNF-reinforced epoxy matrix nanocomposites. In this paper, an in-depth study of both static and dynamic mechanical behaviors and electrical properties of CNF/epoxy nanocomposites with various contents of CNFs is provided. A modified Halpin-Tsai equation is used to evaluate the Young's modulus and storage modulus of the nanocomposites. The values of Young's modulus predicted using this method account for the effect of the CNF agglomeration and fit well with those obtained experimentally. The results show that the highest tensile strength is found in the epoxy nanocomposite with a 1.0 wt% CNFs. The alternate-current (AC electrical properties of the CNF/epoxy nanocomposites exhibit a typical insulator-conductor transition. The conductivity increases by four orders of magnitude with the addition of 0.1 wt% (0.058 vol% CNFs and by ten orders of magnitude for nanocomposites with CNF volume fractions higher than 1.0 wt% (0.578 vol%. The percolation threshold (i.e., the critical CNF volume fraction is found to be at 0.057 vol%.

  11. Characterization of Nanoreinforcement Dispersion in Inorganic Nanocomposites: A Review

    Directory of Open Access Journals (Sweden)

    Nouari Saheb

    2014-05-01

    Full Text Available Metal and ceramic matrix composites have been developed to enhance the stiffness and strength of metals and alloys, and improve the toughness of monolithic ceramics, respectively. It is possible to further improve their properties by using nanoreinforcement, which led to the development of metal and ceramic matrix nanocomposites, in which case, the dimension of the reinforcement is on the order of nanometer, typically less than 100 nm. However, in many cases, the properties measured experimentally remain far from those estimated theoretically. This is mainly due to the fact that the properties of nanocomposites depend not only on the properties of the individual constituents, i.e., the matrix and reinforcement as well as the interface between them, but also on the extent of nanoreinforcement dispersion. Therefore, obtaining a uniform dispersion of the nanoreinforcement in the matrix remains a key issue in the development of nanocomposites with the desired properties. The issue of nanoreinforcement dispersion was not fully addressed in review papers dedicated to processing, characterization, and properties of inorganic nanocomposites. In addition, characterization of nanoparticles dispersion, reported in literature, remains largely qualitative. The objective of this review is to provide a comprehensive description of characterization techniques used to evaluate the extent of nanoreinforcement dispersion in inorganic nanocomposites and critically review published work. Moreover, methodologies and techniques used to characterize reinforcement dispersion in conventional composites, which may be used for quantitative characterization of nanoreinforcement dispersion in nanocomposites, is also presented.

  12. Moessbauer spectroscopic determination of magnetic moments of Fe3+ and Co2+ in substituted barium hexaferrite, Ba(Co,Ti)xFe(12-2x)O19

    International Nuclear Information System (INIS)

    Williams, J.M.; Adetunji, J.; Gregori, M.

    2000-01-01

    We report the distribution of magnetic moments of Fe 3+ and Co 2+ in Co 2+ -, Ti 4+ -substituted M-type barium hexaferrite, Ba(Co,Ti) x Fe (12-2x) O 19 , as a function of doping rate, x. The substitution, x, for iron has been varied with x=0, 0.25, 0.50, 0.70 and 0.85. The magnetic moments of Fe 3+ and Co 2+ were calculated from the combined results of Moessbauer measurements for Fe 3+ ions in the sublattices and neutron diffraction data for the total moments of Fe 3+ and Co 2+ . A comparison of the signs of the magnetic moments of Fe 3+ and Co 2+ ions enabled us to attribute spin directions of the Co 2+ ions in the sublattices of the substituted ferrite samples. The spin directions of Co 2+ are opposite to those of Fe 3+ in the 4f 2 and 2b sublattices. They are reversed from the original directions in the 4f 1 and 12K sublattices when the value of x≥0.70. A quantitative analysis shows that Co 2+ and Ti 4+ ions are preferably substituted into 4f 2 and 12K sublattices, respectively. In addition, while the hyperfine field of Fe 3+ in the 2b sublattice gives rise to the 2b-4f 2 interaction it is the partially substituted Co 2+ ions in the 4f 1 and 12K sublattices that contribute to the near neighbour 2a-4f 1 and 2b-12K types of interaction

  13. Selective Clay Placement Within a Silicate-Clay Epoxy Blend Nanocomposite

    Science.gov (United States)

    Miller, Sandi G (Inventor)

    2013-01-01

    A clay-epoxy nanocomposite may be prepared by dispersing a layered clay in an alkoxy epoxy, such as a polypropylene oxide based epoxide before combining the mixture with an aromatic epoxy to improve the nanocomposite's thermal and mechanical properties.

  14. Textural properties of poly(glycidyl methacrylate) : acid-modified bentonite nanocomposites

    NARCIS (Netherlands)

    Zunic, M.; Milutinovic-Nikolic, A.; Nastasovic, A.; Vukovic, Z.; Loncarevic, D.; Vukovic, I.; Loos, K.; ten Brinke, G.; Jovanovic, D.; Sharma, Bhaskar; Ubaghs, Luc; Keul, Helmut; Höcker, Hartwig; Loontjens, Ton; Benthem, Rolf van; Žunić, M.; Milutinović-Nikolić, A.; Nastasović, A.; Vuković, Z.; Lončarević, D.; Vuković, I.; Jovanović, D.

    The aim of this study was to obtain enhanced textural properties of macroporous crosslinked copolymer poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) by synthesizing nanocomposites with acid-modified bentonite. Nanocomposites were obtained by introducing various amounts of

  15. Multifunctional nanocomposites of chitosan, silver nanoparticles, copper nanoparticles and carbon nanotubes for water treatment: Antimicrobial characteristics.

    Science.gov (United States)

    Morsi, Rania E; Alsabagh, Ahmed M; Nasr, Shimaa A; Zaki, Manal M

    2017-04-01

    Multifunctional nanocomposites of chitosan with silver nanoparticles, copper nanoparticles and carbon nanotubes either as bi- or multifunctional nanocomposites were prepared. Change in the overall morphology of the prepared nanocomposites was observed; carbon nanotubes, Ag NPs and Cu NPs are distributed homogeneously inside the polymer matrix individually in the case of the bi-nanocomposites while a combination of different dimensional shapes; spherical NPs and nanotubes was observed in the multifunctional nanocomposite. Multifunctional nanocomposites has a higher antimicrobial activity, in relative short contact times, against both Gram negative and Gram positive bacteria; E. coli, Staphylococcus aureus; respectively in addition to the fungal strain; Aspergillus flavus isolated from local wastewater sample. The nanocomposites are highly differentiable at the low contact time and low concentration; 1% concentration of the multifunctional nanocomposite is very effective against the tested microbes at contact time of only 10min. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. E-Beam-Cured Layered-Silicate and Spherical Silica Epoxy Nanocomposites (Preprint)

    National Research Council Canada - National Science Library

    Chen, Chenggang; Anderson, David P

    2007-01-01

    .... The nanofillers can be two dimensional (layered-silicate) and zero dimensional (spherical silica). Both the spherical silica epoxy nanocomposite and the layered-silicate epoxy nanocomposite can be cured to a high degree of curing...

  17. Synthesis and utilization of poly (methylmethacrylate) nanocomposites based on modified montmorillonite

    OpenAIRE

    Youssef, Ahmed M.; Malhat, F.M.; Abdel Hakim, A.A.; Dekany, Imre

    2015-01-01

    Poly (methylmethacrylate) nanocomposite was prepared via in-situ emulsion polymerization (PMMA/Mt-CTA). The modified montmorillonite (Mt-CTA) is used as hosts for the preparation of poly (methylmethacrylate) nanocomposites with basal distance 1.95 nm. Moreover, exfoliated nanocomposite was characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). The fashioned nanocomposites exhibited bett...

  18. Synthesis and magnetic properties of bulk transparent PMMA/Fe-oxide nanocomposites

    Science.gov (United States)

    Li, Shanghua; Qin, Jian; Fornara, Andrea; Toprak, Muhammet; Muhammed, Mamoun; Kim, Do Kyung

    2009-05-01

    PMMA/Fe-oxide nanocomposites are fabricated by a chemical method. Monodispersed Fe-oxide nanoparticles are well dispersed in the PMMA matrix by in situ polymerization, resulting in a bulk transparent polymeric nanocomposite. The magnetic behavior of the PMMA/Fe-oxide nanocomposites is investigated. The transparent PMMA/Fe-oxide nanocomposite has potentially interesting magneto-optic applications without compromising the advantages of a lightweight, noncorrosive polymeric material with very high transparency even for bulk samples.

  19. Synthesis and magnetic properties of bulk transparent PMMA/Fe-oxide nanocomposites

    International Nuclear Information System (INIS)

    Li Shanghua; Qin Jian; Fornara, Andrea; Toprak, Muhammet; Muhammed, Mamoun; Kim, Do Kyung

    2009-01-01

    PMMA/Fe-oxide nanocomposites are fabricated by a chemical method. Monodispersed Fe-oxide nanoparticles are well dispersed in the PMMA matrix by in situ polymerization, resulting in a bulk transparent polymeric nanocomposite. The magnetic behavior of the PMMA/Fe-oxide nanocomposites is investigated. The transparent PMMA/Fe-oxide nanocomposite has potentially interesting magneto-optic applications without compromising the advantages of a lightweight, noncorrosive polymeric material with very high transparency even for bulk samples.

  20. Enhanced Thermal, Mechanical and Morphological Properties of CNT/HDPE Nanocomposite Using MMT as Secondary Filler

    OpenAIRE

    M. E. Ali Mohsin; Agus Arsad; Othman Y. Alothman

    2014-01-01

    This study explains the influence of secondary filler on the dispersion of carbon nanotube (CNT) reinforced high density polyethylene (HDPE) nanocomposites (CNT/HDPE). In order to understand the mixed-fillers system, Montmorillonite (MMT) was added to CNT/HDPE nanocomposites. It was followed by investigating their effect on the thermal, mechanical and morphological properties of the aforesaid nanocomposite. Incorporation of 3 wt% each of MMT into CNT/HDPE nanocomposite resulted to the increas...

  1. Tribology of polymeric nanocomposites friction and wear of bulk materials and coatings

    CERN Document Server

    Friedrich, Klaus

    2013-01-01

    Tribology of Polymeric Nanocomposites provides a comprehensive description of polymeric nanocomposites, both as bulk materials and as thin surface coatings, and provides rare, focused coverage of their tribological behavior and potential use in tribological applications. Providing engineers and designers with the preparation techniques, friction and wear mechanisms, property information and evaluation methodology needed to select the right polymeric nanocomposites for the job, this unique book also includes valuable real-world examples of polymeric nanocomposites in a

  2. Oxygen Barrier Properties and Melt Crystallization Behavior of Poly(ethylene terephthalate)/Graphene Oxide Nanocomposites

    OpenAIRE

    Szymczyk, Anna; Paszkiewicz, Sandra; Pawelec, Iwona; Lisiecki, Slawomir; Jotko, Marek; Spitalsky, Zdenko; Mosnácek, Jaroslav; Roslaniec, Zbigniew

    2015-01-01

    Poly(ethylene terephthalate) nanocomposites with low loading (0.1–0.5 wt%) of graphene oxide (GO) have been prepared by using in situ polymerization method. TEM study of nanocomposites morphology has shown uniform distribution of highly exfoliated graphene oxide nanoplatelets in PET matrix. Investigations of oxygen permeability of amorphous films of nanocomposites showed that the nanocomposites had better oxygen barrier properties than the neat PET. The improvement of oxygen permeability for ...

  3. Mechanisms of friction in diamondlike nanocomposite coatings

    International Nuclear Information System (INIS)

    Scharf, T. W.; Ohlhausen, J. A.; Tallant, D. R.; Prasad, S. V.

    2007-01-01

    Diamondlike nanocomposite (DLN) coatings (C:H:Si:O) processed from siloxane precursors by plasma enhanced chemical vapor deposition are well known for their low friction and wear behaviors. In the current study, we have investigated the fundamental mechanisms of friction and interfacial shear strength in DLN coatings and the roles of contact stress and environment on their tribological behavior. Friction and wear measurements were performed from 0.25 to 0.6 GPa contact pressures in three environments: dry ( 2 containing fragments, whereas those formed in dry nitrogen had hydrogenated and long range ordered carbons with practically no SiO 2 fragments, ultimately resulting in much lower interfacial shear strength and COF

  4. Ultrapermeable, reverse-selective nanocomposite membranes.

    Science.gov (United States)

    Merkel, T C; Freeman, B D; Spontak, R J; He, Z; Pinnau, I; Meakin, P; Hill, A J

    2002-04-19

    Polymer nanocomposites continue to receive tremendous attention for application in areas such as microelectronics, organic batteries, optics, and catalysis. We have discovered that physical dispersion of nonporous, nanoscale, fumed silica particles in glassy amorphous poly(4-methyl-2-pentyne) simultaneously and surprisingly enhances both membrane permeability and selectivity for large organic molecules over small permanent gases. These highly unusual property enhancements, in contrast to results obtained in conventional filled polymer systems, reflect fumed silica-induced disruption of polymer chain packing and an accompanying subtle increase in the size of free volume elements through which molecular transport occurs, as discerned by positron annihilation lifetime spectroscopy. Such nanoscale hybridization represents an innovative means to tune the separation properties of glassy polymeric media through systematic manipulation of molecular packing.

  5. Development of magnetoelectric nanocomposite for soft technology

    Science.gov (United States)

    Bitla, Yugandhar; Chu, Ying-Hao

    2018-06-01

    The proliferation of flexible and stretchable electronics has led to substantial advancements in principles, material combinations and technologies. The integration of magnetoelectric systems in soft electronics is inevitable by virtue of their extensive applications. Recently, 2D layered materials have emerged as potential candidates due to their excellent flexibility and atomic-scale thickness scalability in addition to their interesting physics. This paper presents a new perspective on the development of magnetoelectric nanocomposites through materials engineering on a pliant mica with excellent mechanical, thermal and chemical stabilities. The unique features of 2D muscovite mica and the power of van der Waals epitaxy are expected to contribute significantly to the emerging transparent soft-technology research applications.

  6. Wear Resistant Amorphous and Nanocomposite Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Racek, O

    2008-03-26

    Glass forming materials (critical cooling rate <10{sup 4}K.s{sup -1}) are promising for their high corrosion and wear resistance. During rapid cooling, the materials form an amorphous structure that transforms to nanocrystalline during a process of devitrification. High hardness (HV 1690) can be achieved through a controlled crystallization. Thermal spray process has been used to apply coatings, which preserves the amorphous/nanocomposite structure due to a high cooling rate of the feedstock particles during the impact on a substrate. Wear properties have been studied with respect to process conditions and feedstock material properties. Application specific properties such as sliding wear resistance have been correlated with laboratory tests based on instrumented indentation and scratch tests.

  7. Biominerals- hierarchical nanocomposites: the example of bone

    Science.gov (United States)

    Beniash, Elia

    2010-01-01

    Many organisms incorporate inorganic solids in their tissues to enhance their functional, primarily mechanical, properties. These mineralized tissues, also called biominerals, are unique organo-mineral nanocomposites, organized at several hierarchical levels, from nano- to macroscale. Unlike man made composite materials, which often are simple physical blends of their components, the organic and inorganic phases in biominerals interface at the molecular level. Although these tissues are made of relatively weak components at ambient conditions, their hierarchical structural organization and intimate interactions between different elements lead to superior mechanical properties. Understanding basic principles of formation, structure and functional properties of these tissues might lead to novel bioinspired strategies for material design and better treatments for diseases of the mineralized tissues. This review focuses on general principles of structural organization, formation and functional properties of biominerals on the example the bone tissues. PMID:20827739

  8. Mechanical Properties of Graphene-Rubber Nanocomposites

    Science.gov (United States)

    Anhar, N. A. M.; Ramli, M. M.; Hambali, N. A. M. A.; Aziz, A. A.; Mat Isa, S. S.; Danial, N. S.; Abdullah, M. M. A. B.

    2017-11-01

    This research focused on development of wearable sensor device by using Prevulcanized Natural Rubber (PV) and Epoxidized Natural Rubber (ENR 50) latex incorporated with graphene oxide (GO), graphene paste, graphene powder and reduced graphene oxide (rGO) powder. The compounding formulation and calculation were based on phr (parts per hundred rubber) and all the samples were then tested for mechanical properties using Instron 5565 machine. It was found that the sonication effects on tensile strength may have better quality of tensile strength compared to non-sonicated GO. For PV incorporate GO, the optimum loading was best determined at loading 1.5 phr with or without sonication and similar result was recorded for PV/G. For ENR 50 incorporate graphene paste and rGO powder nanocomposite shows the best optimum was at 3.0 phr with 24 hours’ sonication.

  9. Inorganic-organic nanocomposites for optical coatings

    Science.gov (United States)

    Schmidt, Helmut K.; Krug, Herbert; Sepeur-Zeitz, Bernhard; Geiter, Elisabeth

    1997-10-01

    The fabrication of nanoparticles by the sol-gel process and their use in polymeric or sol-gel-derived inorganic-organic composite matrices opens up interesting possibilities for designing new optical materials. Two different routes have been chosen for preparing optical nanocomposites: The first is the so-called 'in situ route,' where the nanoparticles are synthesized in a liquid mixture from Zr-alkoxides in a polymerizable system and diffractive gratings were produced by embossing uncured film. The second is the 'separate' preparation route, where a sterically stabilized dry nanoboehmite powder was completely redispersed in an epoxy group-containing matrix and hard coatings with optical quality on polycarbonate were prepared.

  10. Flammability of polypropylene/organoclay nanocomposites

    International Nuclear Information System (INIS)

    Alves, Tatianny Soares; Barbosa, Renata; Carvalho, Laura Hecker de; Canedo, Eduardo Luis

    2014-01-01

    The flammabilities of nanocomposites made with three polypropylene grades (homo and copolymers) with 5 wt % of organoclay (Cloisite 20A), 5 or 15 wt % of maleated polypropylene as compatibilizer, and 0, 0.5 or 1 wt % of cis-13-docosenamide (Erucamide) as co-intercalant, were studied using the horizontal burning test UL94HB. Masterbatches prepared in an internal mixer were diluted in the polypropylene matrix using a corotating twin-screw extruder, with different screw configurations and operating at 240 or 480 rpm. Results indicate that the high burning rate of the composites was not affected by the processing conditions. For all formulations was observed a significant reduction in smoke release, lack of dripping and the formation of a char surface layer, that protected the core of the samples. (author)

  11. Formation and properties of nylon 6 nanocomposites

    Directory of Open Access Journals (Sweden)

    Fornes T. D.

    2003-01-01

    Full Text Available Sodium montmorillonite clay consists of platelets, one nanometer thick with large lateral dimensions, which can be used to achieve efficient reinforcement of polymer matrices. Formation of these nanocomposites requires modifying the clay with an appropriate organic surface treatment and optimized processing. Some of these techniques and the resulting property improvements (modulus, thermal expansion, heat distortion temperature, etc. are reviewed here. It is shown that shear stress exerted on stacks of clay platelets play an important role in the mechanism of exfoliation. The modulus enhancement observed is of the order predicted by composite theories; however, the clay particles clearly affect the crystalline morphology of the polymer phase which may have an additional effect on some composite properties.

  12. Nanocomposite tribological coatings with 'chameleon' surface adaptation

    International Nuclear Information System (INIS)

    Voevodin, A.A.; Fitz, T.A.; Hu, J.J.; Zabinski, J.S.

    2002-01-01

    Nanocomposite tribological coatings were designed to respond to changing environmental conditions by self-adjustment of their surface properties to maintain good tribological performance in any environment. These smart coatings have been dubbed 'chameleon' because, analogous to a chameleon changing its skin color to avoid predators, the coating changes its 'skin' chemistry and structure to avoid wear. The concept was originally developed using WC, diamondlike carbon, and WS 2 material combination for adaptation to a humid/dry environment cycling. In order to address temperature variation, nanocomposite coatings made of yttria-stabilized zirconia (YSZ) in a gold matrix were developed with encapsulated nanosized reservoirs of MoS 2 and diamondlike carbon (DLC). Coatings were produced using a combination of laser ablation and magnetron sputtering. They were characterized by x-ray photoelectron spectroscopy, x-ray diffraction, transmission electron microscopy, x-ray energy dispersive spectroscopy, and micro-Raman spectroscopy. Results were correlated with mechanical and tribological characterization. Coating hardness was evaluated using nanoindentation, while coating adhesion and toughness were estimated using scratch and Vickers indentation tests. Friction and wear endurance measurements of YSZ/Au/MoS 2 /DLC coatings against steel and Si 3 N 4 balls were performed at room temperature in controlled humidity air, dry nitrogen, and vacuum environments, as well as at 500 deg. C in air. Depending on the environment, coating friction surface changed its chemistry and structure between (i) graphitic carbon for sliding in humid air [coating friction coefficients (c.o.f. 0.10-0.15)], (ii) hexagonal MoS 2 for sliding in dry N 2 and vacuum (c.o.f. 0.02-0.05), and (iii) metallic Au for sliding in air at 500 deg. C (c.o.f. 0.10-0.20). The unique coating skin adaptation realized with YSZ/Au/MoS 2 /DLC and WC/DLC/WS composites proves a universal applicability of the chameleon design

  13. Multifunctional Graphene-Silicone Elastomer Nanocomposite, Method of Making the Same, and Uses Thereof

    Science.gov (United States)

    Pan, Shuyang (Inventor); Aksay, Ilhan A. (Inventor); Prud'Homme, Robert K. (Inventor)

    2018-01-01

    A nanocomposite composition having a silicone elastomer matrix having therein a filler loading of greater than 0.05 wt %, based on total nanocomposite weight, wherein the filler is functional graphene sheets (FGS) having a surface area of from 300 sq m/g to 2630 sq m2/g; and a method for producing the nanocomposite and uses thereof.

  14. PBAT based nanocomposites for medical and industrial applications

    International Nuclear Information System (INIS)

    Fukushima, Kikku; Wu, Meng-Hsiu; Bocchini, Sergio; Rasyida, Amaliya; Yang, Ming-Chien

    2012-01-01

    Poly(butylene adipate-co-terephthalate) (PBAT) based nanocomposites were prepared by melt blending PBAT with 5 and 10 wt.% of clay nanoparticles (unmodified and modified montmorillonites, unmodified and modified fluoro-hectorites, and unmodified sepiolites). All nanocomposites showed a good level of clay distribution and dispersion into PBAT, especially nanocomposites with high clay chemical affinity with the polymer matrix. DSC results showed that addition of layered silicates slightly hindered kinetics and extent of crystallization of PBAT; however, sepiolite particles were able to promote polymer crystallization kinetics and the transformation of the PBAT crystal structure to a more ordered form. Similar increases in the thermal stability of PBAT in nitrogen and air were obtained upon addition of all clays, due to a barrier effect of the clays toward polymer decomposition product ablation. Preliminary biocompatibility tests indicated that PBAT based materials with 10% clay content have good biological safety and display almost no cytotoxicity. The addition of all nanofillers increased the hardness of PBAT matrix. The DMA analysis showed that all nanocomposites presented higher E′ values than neat PBAT, indicating that addition of clays improved the mechanical properties of PBAT. For layered silicate nanocomposites, the main influencing factors on the thermo-mechanical properties appeared to be the aspect ratio and dispersion of clay nanoplatelets, rather than polymer/clay chemical affinity. The highest E′ values of sepiolite based nanocomposites make this nanoparticle the most attractive material for tissue engineering and environmental industrial applications. Highlights: ► PBAT nanocomposites with high thermo-mechanical properties were obtained. ► The effects of clay presence on PBAT crystalline structure were elucidated. ► The presence of the clays used in PBAT showed good biological safety. ► Sepiolites brought the higher improvements in PBAT

  15. PBAT based nanocomposites for medical and industrial applications

    Energy Technology Data Exchange (ETDEWEB)

    Fukushima, Kikku, E-mail: kikku81@gmail.com [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43, Sec. 4, Keelung Rd., Taipei 10607, Taiwan (China); Wu, Meng-Hsiu [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43, Sec. 4, Keelung Rd., Taipei 10607, Taiwan (China); Bocchini, Sergio [Dipartimento di Scienze dei Materiali ed Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Rasyida, Amaliya; Yang, Ming-Chien [Department of Materials Science and Engineering, National Taiwan University of Science and Technology, 43, Sec. 4, Keelung Rd., Taipei 10607, Taiwan (China)

    2012-08-01

    Poly(butylene adipate-co-terephthalate) (PBAT) based nanocomposites were prepared by melt blending PBAT with 5 and 10 wt.% of clay nanoparticles (unmodified and modified montmorillonites, unmodified and modified fluoro-hectorites, and unmodified sepiolites). All nanocomposites showed a good level of clay distribution and dispersion into PBAT, especially nanocomposites with high clay chemical affinity with the polymer matrix. DSC results showed that addition of layered silicates slightly hindered kinetics and extent of crystallization of PBAT; however, sepiolite particles were able to promote polymer crystallization kinetics and the transformation of the PBAT crystal structure to a more ordered form. Similar increases in the thermal stability of PBAT in nitrogen and air were obtained upon addition of all clays, due to a barrier effect of the clays toward polymer decomposition product ablation. Preliminary biocompatibility tests indicated that PBAT based materials with 10% clay content have good biological safety and display almost no cytotoxicity. The addition of all nanofillers increased the hardness of PBAT matrix. The DMA analysis showed that all nanocomposites presented higher E Prime values than neat PBAT, indicating that addition of clays improved the mechanical properties of PBAT. For layered silicate nanocomposites, the main influencing factors on the thermo-mechanical properties appeared to be the aspect ratio and dispersion of clay nanoplatelets, rather than polymer/clay chemical affinity. The highest E Prime values of sepiolite based nanocomposites make this nanoparticle the most attractive material for tissue engineering and environmental industrial applications. Highlights: Black-Right-Pointing-Pointer PBAT nanocomposites with high thermo-mechanical properties were obtained. Black-Right-Pointing-Pointer The effects of clay presence on PBAT crystalline structure were elucidated. Black-Right-Pointing-Pointer The presence of the clays used in PBAT showed

  16. Novel transparent and flexible nanocomposite film prepared from chrysotile nanofibres

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Kun, E-mail: kliu@csu.edu.cn [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China); Zhu, Binnan; Feng, Qiming [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China); Duan, Tao [Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, CAEP, Mianyang 621010 (China)

    2013-10-01

    In the present study, chrysotile nanofibres, obtained from physicochemical dispersion of natural chrysotile, were used to prepare nanofibre sheets by vacuum filtration. As-prepared sheets were then impregnated by UV-curable resin and cured by ultraviolet light to fabricate the flexible and transparent nanocomposite films. Observed from SEM, the transparent films showed a smooth surface and a typical sandwich structure in cross section, viz. nanofibre sheet filled with resin was sandwiched by two layers of resin. XRD patterns indicated the amorphous nature of cured resin and characteristic crystallographic structure of chrysotile in nanocomposite films. Though the nanofibre sheets were white in colour, and nanofibre contents in nanocomposites were as much as 43.4 wt%, the nanocomposite films displayed an excellent optical transparency with about 85% light transmittance in the visible light range. Tensile tests showed that the addition of nanofibres resulted in a great improvement in mechanical strength of the nanocomposite films; with the increase of nanofibre contents, the modulus and tensile strength of nanocomposite films increased gradually. - Graphical abstract: Photos show the experimental phenomenon. The white nanofibre sheets can be written or printed like paper, and it's very interested that the handwriting is clearly visible from the front and back of the transparent films prepared from nanofibre sheets by vacuum impregnation and UV curing. This phenomenon can be attributed to the increase of transparency of film, which results from the replacement of air interstices in nanofibre sheet by resin with higher refractive index. Visible light can pass easily through the transparent film without obvious loss, but can be apparently adsorbed and scattered by ink particles that adhered to nanofibres and embedded in resin. - Highlights: • A flexible and transparent film is prepared from chrysotile nanofibres. • The nanofibre sheet is sandwiched by two

  17. Novel transparent and flexible nanocomposite film prepared from chrysotile nanofibres

    International Nuclear Information System (INIS)

    Liu, Kun; Zhu, Binnan; Feng, Qiming; Duan, Tao

    2013-01-01

    In the present study, chrysotile nanofibres, obtained from physicochemical dispersion of natural chrysotile, were used to prepare nanofibre sheets by vacuum filtration. As-prepared sheets were then impregnated by UV-curable resin and cured by ultraviolet light to fabricate the flexible and transparent nanocomposite films. Observed from SEM, the transparent films showed a smooth surface and a typical sandwich structure in cross section, viz. nanofibre sheet filled with resin was sandwiched by two layers of resin. XRD patterns indicated the amorphous nature of cured resin and characteristic crystallographic structure of chrysotile in nanocomposite films. Though the nanofibre sheets were white in colour, and nanofibre contents in nanocomposites were as much as 43.4 wt%, the nanocomposite films displayed an excellent optical transparency with about 85% light transmittance in the visible light range. Tensile tests showed that the addition of nanofibres resulted in a great improvement in mechanical strength of the nanocomposite films; with the increase of nanofibre contents, the modulus and tensile strength of nanocomposite films increased gradually. - Graphical abstract: Photos show the experimental phenomenon. The white nanofibre sheets can be written or printed like paper, and it's very interested that the handwriting is clearly visible from the front and back of the transparent films prepared from nanofibre sheets by vacuum impregnation and UV curing. This phenomenon can be attributed to the increase of transparency of film, which results from the replacement of air interstices in nanofibre sheet by resin with higher refractive index. Visible light can pass easily through the transparent film without obvious loss, but can be apparently adsorbed and scattered by ink particles that adhered to nanofibres and embedded in resin. - Highlights: • A flexible and transparent film is prepared from chrysotile nanofibres. • The nanofibre sheet is sandwiched by two

  18. Preparation, structure and thermal stability of Cu/LDPE nanocomposites

    International Nuclear Information System (INIS)

    Xia Xianping; Cai Shuizhou; Xie Changsheng

    2006-01-01

    Copper/low-density-polyethylene (Cu/LDPE) nanocomposites have been prepared using a melt-blending technique in a single-screw extruder. Their structure and thermal characteristics are characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results of XRD, SEM and SEM-EDS Cu-mapping show that the nanocomposites are a hybrid of the polymer and the copper nanoparticles, and the copper nanoparticles aggregates were distributed uniformly in general. The results also show that the nanocomposites and the base resin, the pure LDPE, have a different crystalline structure and the same oriented characteristics owing to the presence of copper nanoparticles and the same cooling condition. The results of DSC show that the incorporation of copper nanoparticles can decrease the melting temperatures but increase the crystallization temperatures, and can lower the crystallinity degree of the matrix of the composites. The results of TGA show that the presence of copper nanoparticles can improve the thermal stability of the nanocomposites, a maximum increment of 18 deg. C is obtained comparing with the pure LDPE in this experiment. The results of TGA also show that the influence of the incorporation of the copper nanoparticles on the thermal stability of the Cu/LDPE nanocomposites is different from that of the non-metal nanoparticles on the polymer/non-metal nanocomposites and the copper microparticles on the Cu/LDPE microcomposites. The increase of the thermal stability of the Cu/LDPE nanocomposites will decrease when the content of the copper nanoparticles is more than 2 wt.%. The difference might be caused by the fact that the activity of the metal nanoparticles is much more higher than that of the non-metal nanoparticles, and the different size effect the different copper particles has

  19. High-performance polymer/layered silicate nanocomposites

    Science.gov (United States)

    Heidecker, Matthew J.

    High-performance layered-silicate nanocomposites of Polycarbonate (PC), poly(ethylene terephthalate) (PET), and their blends were produced via conventional melt-blending techniques. The focus of this thesis was on the fundamentals of dispersion, control of thermal stability, maintenance of melt-blending processing conditions, and on optimization of the composites' mechanical properties via the design of controlled and thermodynamically favorable nano-filler dispersions within the polymer matrices. PET and PC require high temperatures for melt-processing, rendering impractical the use of conventional/commercial organically-modified layered-silicates, since the thermal degradation temperatures of their ammonium surfactants lies below the typical processing temperatures. Thus, different surfactant chemistries must be employed in order to develop melt-processable nanocomposites, also accounting for polymer matrix degradation due to water (PET) or amine compounds (PC). Novel high thermal-stability surfactants were developed and employed in montmorillonite nanocomposites of PET, PC, and PC/PET blends, and were compared to the respective nanocomposites based on conventional quaternary-ammonium modified montmorillonites. Favorable dispersion was achieved in all cases, however, the overall material behavior -- i.e., the combination of crystallization, mechanical properties, and thermal degradation -- was better for the nanocomposites based on the thermally-stable surfactant fillers. Studies were also done to trace, and ultimately limit, the matrix degradation of Polycarbonate/montmorillonite nanocomposites, through varying the montmorillonite surfactant chemistry, processing conditions, and processing additives. Molecular weight degradation was, maybe surprisingly, better controlled in the conventional quaternary ammonium based nanocomposites -- even though the thermal stability of the organically modified montmorillonites was in most cases the lowest. Dependence of the

  20. Structure and properties of carbon nanotubes/sol-gel nanocomposites

    International Nuclear Information System (INIS)

    Pokrass, Mariana

    2013-08-01

    Carbon Nanotubes (CNTs) are promising filler materials owing to their exceptional mechanical, electrical, thermal and optical properties. Since their discovery in 1991, a major effort has been made in developing CNT-polymer nanocomposites, whereas CNT/ceramic based nanocomposites, in particularly, CNT/silica nanocomposites, have been very little studied. This thesis focuses on preparation and characterization of novel CNT/silica nanocomposite glasses synthesized by the Sol-Gel technology. A comprehensive analysis of their morphological, optical, and electrical properties was conducted, and analyzed according to existing theoretical models. The nanocomposites hosting matrix is a hybrid organic/inorganic glass prepared by the Fast-Sol-Gel (FSG) route. Using specific conditions in the FSG procedure, the resultant glasses are nonporous, exhibiting no contraction upon drying. Their analogous Classical-Sol-Gel (CSG) glasses, however, are porous, and do exhibit contraction upon drying. The FSG glasses are relatively new materials, and their physical and optical properties were only meagerly studied. In our present work we have conducted a comprehensive experimental research on some previously ignored characteristics such as: UV-vis-IR optical absorption and transmission, and the organic content effect on the refraction index n, density ρ, thermal expansion coefficient β, and thermo-optic coefficient dn/dT. We found that organic residues within the glass decrease the refractive index, density, and thermo-optic coefficient. The thermal expansion coefficient, however, increases with the organic content. A negative linear dependence of the thermo-optic coefficient on the thermal expansion coefficient was obtained. CNT/FSG nanocomposites were prepared by using a solution mixing method, while CNT/CSG nanocomposites were prepared by means of an in situ polymerization technique. Nanocomposites based on FSG hybrid glasses were characterized for their nonlinear optical and

  1. Green aqueous surface modification of polypropylene for novel polymer nanocomposites.

    Science.gov (United States)

    Thakur, Vijay Kumar; Vennerberg, Danny; Kessler, Michael R

    2014-06-25

    Polypropylene is one of the most widely used commercial commodity polymers; among many other applications, it is used for electronic and structural applications. Despite its commercial importance, the hydrophobic nature of polypropylene limits its successful application in some fields, in particular for the preparation of polymer nanocomposites. Here, a facile, plasma-assisted, biomimetic, environmentally friendly method was developed to enhance the interfacial interactions in polymer nanocomposites by modifying the surface of polypropylene. Plasma treated polypropylene was surface-modified with polydopamine (PDA) in an aqueous medium without employing other chemicals. The surface modification strategy used here was based on the easy self-polymerization and strong adhesion characteristics of dopamine (DA) under ambient laboratory conditions. The changes in surface characteristics of polypropylene were investigated using FTIR, TGA, and Raman spectroscopy. Subsequently, the surface modified polypropylene was used as the matrix to prepare SiO2-reinforced polymer nanocomposites. These nanocomposites demonstrated superior properties compared to nanocomposites prepared using pristine polypropylene. This simple, environmentally friendly, green method of modifying polypropylene indicated that polydopamine-functionalized polypropylene is a promising material for various high-performance applications.

  2. Plasmonic, excitonic and exciton-plasmonic photoinduced nanocomposites

    Science.gov (United States)

    Bityurin, N.; Ermolaev, N.; Smirnov, A. A.; Afanasiev, A.; Agareva, N.; Koryukina, T.; Bredikhin, V.; Kamensky, V.; Pikulin, A.; Sapogova, N.

    2016-03-01

    UV irradiation of materials consisting of a polymer matrix that possesses precursors of different kinds can result in creation of nanoparticles within the irradiated domains. Such photoinduced nanocomposites are promising for photonic applications due to the strong alteration of their optical properties compared to initial non-irradiated materials. We report our results on the synthesis and investigation of plasmonic, excitonic and exciton-plasmonic photoinduced nanocomposites. Plasmonic nanocomposites contain metal nanoparticles of noble metals with a pronounced plasmon resonance. Excitonic nanocomposites possess semiconductor nanoclusters (quantum dots). We consider the CdS-Au pair because the luminescent band of CdS nanoparticles enters the plasmon resonance band of gold nanoparticles. The obtaining of such particles within the same composite materials is promising for the creation of media with exciton-plasmon resonance. We demonstrate that it is possible to choose appropriate precursor species to obtain the initially transparent poly(methyl methacrylate) (PMMA) films containing both types of these molecules either separately or together. Proper irradiation of these materials by a light-emitting diode operating at the wavelength of 365 nm provides material alteration demonstrating light-induced optical absorption and photoluminescent properties typical for the corresponding nanoparticles. Thus, an exciton-plasmonic photoinduced nanocomposite is obtained. It is important that here we use the precursors that are different from those usually employed.

  3. Recent advances in clay mineral-containing nanocomposite hydrogels.

    Science.gov (United States)

    Zhao, Li Zhi; Zhou, Chun Hui; Wang, Jing; Tong, Dong Shen; Yu, Wei Hua; Wang, Hao

    2015-12-28

    Clay mineral-containing nanocomposite hydrogels have been proven to have exceptional composition, properties, and applications, and consequently have attracted a significant amount of research effort over the past few years. The objective of this paper is to summarize and evaluate scientific advances in clay mineral-containing nanocomposite hydrogels in terms of their specific preparation, formation mechanisms, properties, and applications, and to identify the prevailing challenges and future directions in the field. The state-of-the-art of existing technologies and insights into the exfoliation of layered clay minerals, in particular montmorillonite and LAPONITE®, are discussed first. The formation and structural characteristics of polymer/clay nanocomposite hydrogels made from in situ free radical polymerization, supramolecular assembly, and freezing-thawing cycles are then examined. Studies indicate that additional hydrogen bonding, electrostatic interactions, coordination bonds, hydrophobic interaction, and even covalent bonds could occur between the clay mineral nanoplatelets and polymer chains, thereby leading to the formation of unique three-dimensional networks. Accordingly, the hydrogels exhibit exceptional optical and mechanical properties, swelling-deswelling behavior, and stimuli-responsiveness, reflecting the remarkable effects of clay minerals. With the pivotal roles of clay minerals in clay mineral-containing nanocomposite hydrogels, the nanocomposite hydrogels possess great potential as superabsorbents, drug vehicles, tissue scaffolds, wound dressing, and biosensors. Future studies should lay emphasis on the formation mechanisms with in-depth insights into interfacial interactions, the tactical functionalization of clay minerals and polymers for desired properties, and expanding of their applications.

  4. Graphene-polyethylenedioxythiophene conducting polymer nanocomposite based supercapacitor

    International Nuclear Information System (INIS)

    Alvi, Farah; Ram, Manoj K.; Basnayaka, Punya A.; Stefanakos, Elias; Goswami, Yogi; Kumar, Ashok

    2011-01-01

    Graphical abstract: Schematic diagrams of an electrochemical double layer type capacitor showing the charged (left) and discharged (right) states. Highlights: → The Graphene-PEDOT nanocomposite based smart coating has shown the excellent redox properties in acidic, organic electrolytes, which is promising for suprecapcitor application. → The electrochemical impedance studies have also been estimated which clearly indicates the high conductivity and less charge transfer resistance in the synthesized material. → The specific capacitance of 380F/g have been calculated for G-Pedot material, also it shows the columbic efficiency of 95% for 800 cycles, which tells the remarkable stability of synthesized material. - Abstract: We present here the synthesis, characterization and application of graphene (G)-polyethylenedioxythiophene (PEDOT) nanocomposites as electrode material for supercapacitor applications. The G-PEDOT nanocomposite was synthesized using a chemical oxidative polymerization technique, and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, FTIR spectroscopy, X-ray-diffraction, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV) techniques. The electrochemical charge/discharge characteristics of G-PEDOT nanocomposites were investigated in different electrolytic media, and the specific discharge capacitance was estimated to be 374 Farad/gram (F/gm). This manuscript presents the capacitance studies on supercapacitor G-PEDOT electrode with respect to stability of material, specific capacitance, electrical conductivity and specific charge/discharge properties of the supercapacitor electrodes. Our study has revealed that the G-PEDOT nanocomposite could be a transformable and viable electrode material for supercapacitor applications.

  5. Polymer nanocomposites for high-temperature composite repair

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Xia [Iowa State Univ., Ames, IA (United States)

    2008-01-01

    A novel repair agent for resin-injection repair of advanced high temperature composites was developed and characterized. The repair agent was based on bisphenol E cyanate ester (BECy) and reinforced with alumina nanoparticles. To ensure good dispersion and compatibility with the BECy matrix in nanocomposites, the alumina nanoparticles were functionalized with silanes. The BECy nanocomposites, containing bare and functionalized alumina nanoparticles, were prepared and evaluated for their thermal, mechanical, rheological, and viscoelastic properties. The monomer of BECy has an extremely low viscosity at ambient temperature, which is good for processability. The cured BECy polymer is a highly cross-linked network with excellent thermal mechanical properties, with a high glass transition temperature (Tg) of 270 C and decomposition temperature above 350 C. The incorporation of alumina nanoparticles enhances the mechanical and rheological properties of the BECy nanocomposites. Additionally, the alumina nanoparticles are shown to catalyze the cure of BECy. Characterization of the nanocomposites included dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, rheological and rheokinetic evaluation, and transmission electron microscopy. The experimental results show that the BECy nanocomposite is a good candidate as repair agent for resin-injection repair applications.

  6. Synthesis of PbS/poly (vinyl-pyrrolidone) nanocomposite

    International Nuclear Information System (INIS)

    Patel, Jayesh D.; Chaudhuri, Tapas K.

    2009-01-01

    A simple solution growth method for synthesis of nanocomposite of PbS nanoparticles in poly(vinyl-pyrrolidone) (PVP) polymer is described. The nanocomposite is prepared from methanolic solution of lead acetate (PbAc), thiourea (TU) and PVP at room temperature (∼27 deg. C). Optical absorption spectrum of PbS/PVP nanocomposite solution shows strong absorption from 300 to 650 nm with significant bands at 400 and 590 nm which is characteristic of nanoscale PbS. Spin-coated nanocomposite films on glass have an absorption edge at ∼650 nm with band gap of 2.55 eV. Fourier transform infrared (FTIR) spectroscopy of PbS/PVP nanocomposite and PVP shows strong chemical bond between PbS nanoparticles and host PVP polymer. The transmission electron microscope (TEM) images reveal that 5-10 nm PbS particles are evenly embedded in PVP polymer. The formation of PbS is confirmed by selective area electron diffraction (SAED) of a typical nanoparticle.

  7. Performance of epoxy-nanocomposite under corrosive environment

    Directory of Open Access Journals (Sweden)

    2007-06-01

    Full Text Available Nanocomposite materials consisting of polymeric matrix materials and natural or synthetic layered minerals like clay are currently an expanding field of study because these new materials often exhibit a wide range of improved properties over their unmodified starting polymers. Epoxy/organoclay nanocomposites have been prepared by intercalating epoxy into the organoclay via direct mixing process. The clay exfoliation was monitored by X-ray diffraction (XRD and transmission electron microscopy (TEM. Water diffusion and sulfuric acid corrosion resistance of epoxy-based nanocomposites were evaluated. Diffusion was studied through epoxy samples containing up to 6 phr (parts per hundred resin of an organically treated montmorillonite. The diffusion of the environmental solution was measured by noting the increase in weight of the samples as a function of immersion time in these solutions at 80°C. The effect of the degree of exfoliation of the organoclay on water barrier and corrosion resistance was specifically studied. The data have been compared to those obtained from the neat epoxy resin to evaluate the diffusion properties of the nanocomposites. The flexural strength of the epoxy/organoclay nanocomposites samples made was examined to compare their mechanical performance under corrosive conditions as a function of immersion time and temperature. It was found, that the organoclay was mainly intercalated with some exfoliation and that addition of the organoclay yields better flexural strength retention under immersion into sulfuric acid.

  8. Temperature-Dependent Dielectric Properties of Al/Epoxy Nanocomposites

    Science.gov (United States)

    Wang, Zijun; Zhou, Wenying; Sui, Xuezhen; Dong, Lina; Cai, Huiwu; Zuo, Jing; Chen, Qingguo

    2016-06-01

    Broadband dielectric spectroscopy was carried out to study the transition in electrical properties of Al/epoxy nanocomposites over the frequency range of 1-107 Hz and the temperature range of -20°C to 200°C. The dielectric permittivity, dissipation factor, and electrical conductivity of the nanocomposites increased with temperature and showed an abrupt increase around the glass transition temperature ( T g). The results clearly reveal an interesting transition of the electrical properties with increasing temperature: insulator below 70°C, conductor at about 70°C. The behavior of the transition in electrical properties of the nanocomposites was explored at different temperatures. The presence of relaxation peaks in the loss tangent and electric modulus spectra of the nanocomposites confirms that the chain segmental dynamics of the polymer is accompanied by the absorption of energy given to the system. It is suggested that the temperature-dependent transition of the electric properties in the nanocomposite is closely associated with the α-relaxation. The large increase in the dissipation factor and electric conductivity depends on the direct current conduction of thermally activated charge carriers resulting from the epoxy matrix above T g.

  9. Liquid crystalline epoxy nanocomposite material for dental application.

    Science.gov (United States)

    Tai, Yun-Yuan; Hsu, Sheng-Hao; Chen, Rung-Shu; Su, Wei-Fang; Chen, Min-Huey

    2015-01-01

    Novel liquid crystalline epoxy nanocomposites, which exhibit reduced polymerization shrinkage and effectively bond to tooth structures, can be applied in esthetic dentistry, including core and post systems, direct and indirect restorations, and dental brackets. The purposes of this study were to investigate the properties of liquid crystalline epoxy nanocomposites including biocompatibility, microhardness, and frictional forces of bracket-like blocks with different filler contents for further clinical applications. In this study, we evaluated liquid crystalline epoxy nanocomposite materials that exhibited various filler contents, by assessing their cell activity performance using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and their microhardness with or without thermocycling. We also evaluated the frictional force between bracket-like duplicates and commercially available esthetic bracket systems using Instron 5566. The liquid crystalline epoxy nanocomposite materials showed good biocompatibility. The materials having high filler content demonstrated greater microhardness compared with commercially available bracket materials, before and after the thermocycling treatment. Thus, manufacturing processes are important to reduce frictional force experienced by orthodontic brackets. The microhardness of the bracket-like blocks made by our new material is superior to the commercially available brackets, even after thermocycling. Our results indicate that the evaluated liquid crystalline epoxy nanocomposite materials are of an appropriate quality for application in dental core and post systems and in various restorations. By applying technology to refine manufacturing processes, these new materials could also be used to fabricate esthetic brackets for orthodontic treatment. Copyright © 2014. Published by Elsevier B.V.

  10. Enhancement of mechanical properties of epoxy/graphene nanocomposite

    Science.gov (United States)

    Berhanuddin, N. I. C.; Zaman, I.; Rozlan, S. A. M.; Karim, M. A. A.; Manshoor, B.; Khalid, A.; Chan, S. W.; Meng, Q.

    2017-10-01

    Graphene is a novel class of nanofillers possessing outstanding characteristics including most compatible with most polymers, high absolute strength, high aspect ratio and cost effectiveness. In this study, graphene was used to reinforce epoxy as a matrix, to enhance its mechanical properties. Two types of epoxy composite were developed which are epoxy/graphene nanocomposite and epoxy/modified graphene nanocomposite. The fabrication of graphene was going through thermal expansion and sonication process. Chemical modification was only done for modified graphene where 4,4’-Methylene diphenyl diisocyanate (MDI) is used. The mechanical properties of both nanocomposite, such as Young’s modulus and maximum stress were investigated. Three weight percentage were used for this study which are 0.5 wt%, 1.0 wt% and 1.5 wt%. At 0.5 wt%, modified and unmodified shows the highest value compared to neat epoxy, where the value were 8 GPa, 6 GPa and 0.675 GPa, respectively. For maximum stress, neat epoxy showed the best result compared to both nanocomposite due to the changes of material properties when adding the filler into the matrix. Therefore, both nanocomposite increase the mechanical properties of the epoxy, however modification surface of graphene gives better improvement.

  11. Atomistic modeling of thermomechanical properties of SWNT/Epoxy nanocomposites

    Science.gov (United States)

    Fasanella, Nicholas; Sundararaghavan, Veera

    2015-09-01

    Molecular dynamics simulations are performed to compute thermomechanical properties of cured epoxy resins reinforced with pristine and covalently functionalized carbon nanotubes. A DGEBA-DDS epoxy network was built using the ‘dendrimer’ growth approach where 75% of available epoxy sites were cross-linked. The epoxy model is verified through comparisons to experiments, and simulations are performed on nanotube reinforced cross-linked epoxy matrix using the CVFF force field in LAMMPS. Full stiffness matrices and linear coefficient of thermal expansion vectors are obtained for the nanocomposite. Large increases in stiffness and large decreases in thermal expansion were seen along the direction of the nanotube for both nanocomposite systems when compared to neat epoxy. The direction transverse to nanotube saw a 40% increase in stiffness due to covalent functionalization over neat epoxy at 1 K whereas the pristine nanotube system only saw a 7% increase due to van der Waals effects. The functionalized SWNT/epoxy nanocomposite showed an additional 42% decrease in thermal expansion along the nanotube direction when compared to the pristine SWNT/epoxy nanocomposite. The stiffness matrices are rotated over every possible orientation to simulate the effects of an isotropic system of randomly oriented nanotubes in the epoxy. The randomly oriented covalently functionalized SWNT/Epoxy nanocomposites showed substantial improvements over the plain epoxy in terms of higher stiffness (200% increase) and lower thermal expansion (32% reduction). Through MD simulations, we develop means to build simulation cells, perform annealing to reach correct densities, compute thermomechanical properties and compare with experiments.

  12. Physicochemical properties of nanocomposite: Hydroxyapatite in reduced graphene oxide.

    Science.gov (United States)

    Rajesh, A; Mangamma, G; Sairam, T N; Subramanian, S; Kalavathi, S; Kamruddin, M; Dash, S

    2017-07-01

    Graphene oxide (GO) based nanocomposites have gained considerable attention in the field of material science due to their excellent physicochemical and biological properties. Incorporation of nanomaterials into GO sheets prevents the formation of π-π stacking bond thereby giving rise to composites that show the improved properties compared to their individual counterparts. In this work, reduced graphene oxide (rGO) - hydroxyapatite (HAP) nanocomposites were synthesized by ultrasonic method. Increasing the c/a ratio of HAP in the diffraction pattern of rGO/HAP nanocomposites indicates the c-axis oriented grown HAP nanorods interacting with rGO layers. Shift in wavenumber (15cm -1 ) and increase of full width at half maximum (45cm -1 ) of G band in Raman spectra of the rGO/HAP nanocomposites are observed and attributed to the tensile strain induced due to the intercalated HAP nanorods between the rGO layers. Atomic force microscopy (AFM) and phase imaging studies revealed the intercalation of HAP nanorod with diameter 30nm and length 110-120nm in rGO sheets was clearly perceived along with improved elasticity compared to pristine HAP. 13 C-NMR results proved the synergistic interaction between both components in rGO/HAP nanocomposite. The novel properties observed and the microscopic mechanism responsible for this are a result of the structural modification in rGO layers brought about by the intercalation of HAP nanorods. Copyright © 2017. Published by Elsevier B.V.

  13. Preparation of new conductive polymer nanocomposites for cadmium removal from industrial wastewaters

    International Nuclear Information System (INIS)

    Zoleikani, Leila; Issazadeh, Hossein; ZareNezhad, Bahman

    2015-01-01

    Different conductive polymer nanocomposites have been synthesized, characterized and tested, regarding the removal of cadmium from industrial wastewaters. The chemical structure and morphology are studied by FTIR spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The cadmium removal performance, using the produced polypyrrole, polyaniline and polythiophene nanocomposites, are about 40.2 %, 59 % and 99.94 %, respectively, suggesting the superior performance of synthesized polythiophene conductive nanocomposite for cadmium removal from industrial wastewaters. It is shown that the Langmuir adsorption model can be used for accurate description of cadmium removal mechanism using different synthesized conductive nanocomposites. Keywords : wastewater, nanocomposite, polythiophene, cadmium removal, conductive polymer.

  14. STUDY ON BIODEGRADABILITY OF POLY (3-HYDROXYBUTYRATE-co-3-HYDROXYVALERATE)/ORGANOPHILIC MONTMORILLONITE NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    WANG Shufang; SONG Cunjiang; CHEN Guangxin; LIU Jing; YANG Chao; ZHANG Xihui; GUO Tianying; ZHANG Banghua

    2004-01-01

    Poly (3-hydroxybutyrate-co-3-hydroxyvalerate)/Organophilic montmorillonite (PHBV/OMMT) nanocomposites were prepared and the biodegradability of the PHBV/OMMT nanocomposites was studied by a cultivation degrading method in soil suspension. The relationship between structure and biodegradability of PHBV/OMMT nanocomposites was investigated. The results showed that the biodegradability of PHBV/OMMT nanocomposites decreased with increasing amount of OMMT and it was related to the number of PHBV degrading microorganisms in degradation environment, the anti-microbial property of OMMT and the degree of crystallinity of the nanocomposites.

  15. Preparation and Properties of Polyester-Based Nanocomposite Gel Coat System

    Directory of Open Access Journals (Sweden)

    P. Jawahar

    2006-01-01

    Full Text Available Nanocomposite gel coat system is prepared using unsaturated polyester resin with aerosil powder, CaCO3, and organoclay. The influence of organoclay addition on mechanical and water barrier properties of gel coat system is studied for different amount (1, 2, and 3 wt % of organoclay. The nanolevel incorporation of organoclay improves the mechanical and water barrier properties of nanocomposite gel coat system. The nanocomposite gel coat system exhibits 55% improvement in tensile modulus and 25% improvement in flexural modulus. There is a 30% improvement in impact property of nanocomposite gel coat system. The dynamic mechanical analysis shows a slight increase in glass transition temperature for nanocomposite gel coat system.

  16. Poly(vinyl acetate)/clay nanocomposite materials for organic thin film transistor application.

    Science.gov (United States)

    Park, B J; Sung, J H; Park, J H; Choi, J S; Choi, H J

    2008-05-01

    Nanocomposite materials of poly(vinyl acetate) (PVAc) and organoclay were fabricated, in order to be utilized as dielectric materials of the organic thin film transistor (OTFT). Spin coating condition of the nanocomposite solution was examined considering shear viscosity of the composite materials dissolved in chloroform. Intercalated structure of the PVAc/clay nanocomposites was characterized using both wide-angle X-ray diffraction and TEM. Fracture morphology of the composite film on silicon wafer was also observed by SEM. Dielectric constant (4.15) of the nanocomposite materials shows that the PVAc/clay nanocomposites are applicable for the gate dielectric materials.

  17. Development of novel nano-composite membranes as introduction systems for mass spectrometers: Contrasting nano-composite membranes and conventional inlet systems

    Science.gov (United States)

    Miranda, Luis Diego

    This dissertation presents the development of novel nano-composite membranes as introduction systems for mass spectrometers. These nano-composite membranes incorporate anodic aluminum oxide (AAO) membranes as templates that can be used by themselves or modified by a variety of chemical deposition processes. Two types of nano-composite membranes are presented. The first nano-composite membrane has carbon deposited within the pores of an AAO membrane. The second nano-composite membrane is made by coating an AAO membrane with a thin polymer film. The following chapters describe the transmission properties these nano-composite membranes and compare them to conventional mass spectrometry introduction systems. The nano- composite membranes were finally coupled to the inlet system of an underwater mass spectrometer revealing their utility in field deployments.

  18. Graphene Synthesis & Graphene/Polymer Nanocomposites

    Science.gov (United States)

    Liao, Ken-Hsuan

    We successfully developed a novel, fast, hydrazine-free, high-yield method for producing single-layered graphene. Graphene sheets were formed from graphite oxide by reduction with de-ionized water at 130 ºC. Over 65% of the sheets are single graphene layers. A dehydration reaction of exfoliated graphene oxide was utilized to reduce oxygen and transform C-C bonds from sp3 to sp2. The reduction appears to occur in large uniform interconnected oxygen-free patches so that despite the presence of residual oxygen the sp2 carbon bonds formed on the sheets are sufficient to provide electronic properties comparable to reduced graphene sheets obtained using other methods. Cytotoxicity of aqueous graphene was investigated with Dr. Yu-Shen Lin by measuring mitochondrial activity in adherent human skin fibroblasts using two assays. The methyl-thiazolyl-diphenyl-tetrazolium bromide (MTT) assay, a typical nanotoxicity assay, fails to predict the toxicity of graphene oxide and graphene toxicity because of the spontaneous reduction of MTT by graphene and graphene oxide, resulting in a false positive signal. An appropriate alternate assessment, using the water soluble tetrazolium salt (WST-8) assay, reveals that the compacted graphene sheets are more damaging to mammalian fibroblasts than the less densely packed graphene oxide. Clearly, the toxicity of graphene and graphene oxide depends on the exposure environment (i.e. whether or not aggregation occurs) and mode of interaction with cells (i.e. suspension versus adherent cell types). Ultralow percolation concentration of 0.15 wt% graphene, as determined by surface resistance and modulus, was observed from in situ polymerized thermally reduced graphene (TRG)/ poly-urethane-acrylate (PUA) nanocomposite. A homogeneous dispersion of TRG in PUA was revealed by TEM images. The aspect ratio of dispersed TRG, calculated from percolation concentration and modulus, was found to be equivalent to the reported aspect ratio of single

  19. Polyaniline/partially exfoliated multi-walled carbon nanotubes based nanocomposites for supercapacitors

    International Nuclear Information System (INIS)

    Potphode, Darshna D.; Sivaraman, P.; Mishra, Sarada P.; Patri, Manoranjan

    2015-01-01

    In the present study, polyaniline (PANI)/partially exfoliated multi-walled carbon nanotubes (Px-MWCNT) nanocomposites were investigated for supercapacitor application. Nanocomposites with varying weight/weight ratio of PANI and Px-MWCNT were prepared by in-situ polymerization of aniline over Px-MWCNT. Transmission and scanning electron microscopic analysis showed that the MWCNT was partial unzipped along the length of tubes. The morphology of PANI/Px-MWCNT nanocomposites exhibited wrapping of PANI over Px-MWCNT. Symmetric supercapacitors containing PANI/Px-MWCNT nanocomposites as the electrode material were fabricated. The electrochemical characterization of the nanocomposites was carried by two electrode method (unit cell configuration). Cyclic voltammetric analysis showed a synergistic increase in specific capacitance of the nanocomposites. Charge-discharge cycle study indicated that nanocomposites have greater charge-discharge rate capability than pure PANI. The observed result is attributed to the shorter diffusion length of ions in the nanocomposites as compared to that of pure PANI. The electrochemical impedance spectra of supercapacitors were resolved into real and losscapacitances. The loss capacitance indicated that the time constant of the nanocomposites decreases with increase in the Px-MWCNT content. The supercapacitors showed enhanced stability during continuous charge-discharge cycling as the PX-MWCNT content in the nanocomposites increased. PANI-50 and PANI-25 nanocomposites based supercapacitors exhibited 91% and 93% capacitive retention after 2000 charge-discharge cycle while pure PANI showed only 67% capacitance retention for the same number of cycles

  20. Effect of Saline Solution on the Electrical Response of Single Wall Carbon Nanotubes-Epoxy Nanocomposites

    Directory of Open Access Journals (Sweden)

    Hammad Younes

    2017-01-01

    Full Text Available The effects of saline solution on the electrical resistance of single wall carbon nanotubes-epoxy nanocomposites have been investigated experimentally. Ultrasonic assisted fabricated 1.0% and 0.5 W/W% SWCNTs epoxy nanocomposites are integrated into a Kelvin structure by smear cast the nanocomposites on a glass wafer. Four metal pads are deposited on the nanocomposites using the beam evaporator and wires are tethered using soldering. The effect of saline solution on the electrical resistance of the nanocomposites is studied by adding drop of saline solution to the surface of the fabricated nanocomposites and measuring electrical resistance. Moreover, the nanocomposites are soaked completely into 3 wt.% saline solution and real-time measurement of the electrical resistance is conducted. It is found that a drop of saline solution on the surface of the nanocomposites film increases the resistance by 50%. Furthermore, the real-time measurement reveals a 40% increase in the resistance of the nanocomposites film. More importantly, the nanocomposites are successfully reset by soaking in DI water for four hours. This study may open the door for using SWCNTs epoxy nanocomposites as scale sensors in oil and gas industry.

  1. Effect of cellulose nanocrystals (CNCs) on crystallinity, mechanical and rheological properties of polypropylene/CNCs nanocomposites

    Science.gov (United States)

    Bagheriasl, D.; Carreau, P. J.; Dubois, C.; Riedl, B.

    2015-05-01

    Rheological and mechanical properties of polypropylene (PP)/CNCs nanocomposites were compared with those of nanocomposites containing poly(ethylene-co-vinyl alcohol) as a compatibilizer. The nanocomposites were prepared by a Brabender internal mixer at CNC contents of 5 wt%. The compression molded nanocomposite dog-bones and disks were characterized regarding their tensile and dynamic rheological behavior, respectively. The complex viscosity of the nanocomposites samples containing the compatibilizer were increased, slightly, compared to the non-compatibilized nanocomposite samples. Moreover, an overshoot in the transient start-up viscosity of the compatibilized nanocomposite was observed. The Young modulus of the nanocomposite samples containing the compatibilizer were increased up to ca. 37% compared to the neat PP. The elongation at break was decreased in all PP/CNC nanocomposite samples, but less for the nanocomposite samples containing the compatibilizer. The crystalline content of the PP in the nanocomposites and also the crystallization temperature were increased after compatibilization. These results could be ascribed to the efficiency of the poly(ethylene-co-vinyl alcohol) as a compatibilizer that favors a better dispersion and wetting of the hydrophilic CNCs within the hydrophobic PP.

  2. Studies on preparation and properties of the multi-walled carbon nanotubes (MWNTs)/epoxy nanocomposites

    International Nuclear Information System (INIS)

    Deng Huayang; Cao Qi; Wang Xianyou; Chen Quanqi; Kuang Hao; Wang Xiaofeng

    2011-01-01

    Highlights: → We use the modified MWNTs as fillers fabricated epoxy nanocomposites. → The mechanical, thermal and dielectric properties of nanocomposites are measured. → The nanocomposites exhibited better mechanical and dielectric properties. - Abstract: The MWNTs were coated with polyaniline (PANI) by in situ chemical oxidation polymerization method. FTIR spectroscopy, scanning electron microscope (SEM) and X-ray diffraction (XRD) indicated that the MWNTs were coated with PANI. The MWNTs/epoxy nanocomposites were fabricated by using the solution blending method. Differential scanning calorimetry (DSC), tensile testing, HP 4294A impedance analyzer and SEM were used to investigate the properties of the nanocomposites. The results showed that the modified carbon nanotubes were well dispersed in the polymer matrix. The nanocomposites have enhancements in mechanical, thermal and dielectric properties compare with the neat epoxy resin. The nanocomposites were proven to be a good polymer dielectric material.

  3. Nanocomposite tribological coatings with "chameleon" surface adaptation

    Science.gov (United States)

    Voevodin, A. A.; Fitz, T. A.; Hu, J. J.; Zabinski, J. S.

    2002-07-01

    Nanocomposite tribological coatings were designed to respond to changing environmental conditions by self-adjustment of their surface properties to maintain good tribological performance in any environment. These smart coatings have been dubbed "chameleon" because, analogous to a chameleon changing its skin color to avoid predators, the coating changes its "skin" chemistry and structure to avoid wear. The concept was originally developed using WC, diamondlike carbon, and WS2 material combination for adaptation to a humid/dry environment cycling. In order to address temperature variation, nanocomposite coatings made of yttria-stabilized zirconia (YSZ) in a gold matrix were developed with encapsulated nanosized reservoirs of MoS2 and diamondlike carbon (DLC). Coatings were produced using a combination of laser ablation and magnetron sputtering. They were characterized by x-ray photoelectron spectroscopy, x-ray diffraction, transmission electron microscopy, x-ray energy dispersive spectroscopy, and micro-Raman spectroscopy. Results were correlated with mechanical and tribological characterization. Coating hardness was evaluated using nanoindentation, while coating adhesion and toughness were estimated using scratch and Vickers indentation tests. Friction and wear endurance measurements of YSZ/Au/MoS2/DLC coatings against steel and Si3N4 balls were performed at room temperature in controlled humidity air, dry nitrogen, and vacuum environments, as well as at 500 degC in air. Depending on the environment, coating friction surface changed its chemistry and structure between (i) graphitic carbon for sliding in humid air [coating friction coefficients (c.o.f. 0.10-0.15)], (ii) hexagonal MoS2 for sliding in dry N2 and vacuum (c.o.f. 0.02-0.05), and (iii) metallic Au for sliding in air at 500 degC (c.o.f. 0.10-0.20). The unique coating skin adaptation realized with YSZ/Au/MoS2/DLC and WC/DLC/WS composites proves a universal applicability of the chameleon design concept

  4. Polyurethane Organosilicate Nanocomposites as Blood Compatible Coatings

    Directory of Open Access Journals (Sweden)

    Johnson H. Y. Chung

    2012-02-01

    Full Text Available Polymer clay nanocomposites (NCs show remarkable potential in the field of drug delivery due to their enhanced barrier properties. It is hypothesised that well dispersed clay particles within the polymer matrix create a tortuous pathway for diffusing therapeutic molecules, thereby resulting in more sustained release of the drug. As coatings for medical devices, these materials can simultaneously modulate drug release and improve the mechanical performance of an existing polymer system without introducing additional materials with new chemistries that can lead to regulatory concerns. In this study, polyurethane organosilicate nanocomposites (PUNCs coated onto stainless steel wires were evaluated for their feasibility as blood compatible coatings and as drug delivery systems. Heparin was selected as the model drug to examine the impact of silicate loading and modifier chain length in modulating release. Findings revealed that better dispersion was achieved from samples with lower clay loadings and longer alkyl chains. The blood compatibility of PUNCs as assessed by thrombin generation assays showed that the addition of silicate particles did not significantly decrease the thrombin generation lag time (TGT, p = 0.659 or the peak thrombin (p = 0.999 of polyurethane (PU. PUNC coatings fabricated in this research were not cytotoxic as examined by the cell growth inhibition assay and were uniformly intact, but had slightly higher growth inhibition compared to PU possibly due to the presence of organic modifiers (OM. The addition of heparin into PUNCs prolonged the TGT, indicating that heparin was still active after the coating process. Cumulative heparin release profiles showed that the majority of heparin released was from loosely attached residues on the surface of coils. The addition of heparin further prolonged the TGT as compared to coatings without added heparin, but a slight decrease in heparin activity was observed in the NCs

  5. Carbon nanotube epoxy nanocomposites: the effects of interfacial modifications on the dynamic mechanical properties of the nanocomposites.

    Science.gov (United States)

    Yoonessi, Mitra; Lebrón-Colón, Marisabel; Scheiman, Daniel; Meador, Michael A

    2014-10-08

    Surface functionalization of pretreated carbon nanotubes (CNT) using aromatic, aliphatic, and aliphatic ether diamines was performed. The pretreatment of the CNT consisted of either acid- or photo-oxidation. The acid treated CNT had a higher initial oxygen content compared to the photo-oxidized CNT and this resulted in a higher density of functionalization. X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA) were used to verify the presence of the oxygenated and amine moieties on the CNT surfaces. Epoxy/0.1 wt % CNT nanocomposites were prepared using the functionalized CNT and the bulk properties of the nanocomposites were examined. Macroscale correlations between the interfacial modification and bulk dynamic mechanical and thermal properties were observed. The amine modified epoxy/CNT nanocomposites exhibited up to a 1.9-fold improvement in storage modulus (G') below the glass transition (Tg) and up to an almost 4-fold increase above the Tg. They also exhibited a 3-10 °C increase in the glass transition temperature. The aromatic diamine surface modified epoxy/CNT nanocomposites resulted in the largest increase in shear moduli below and above the Tg and the largest increase in the Tg. Surface examination of the nanocomposites with scanning electron microscopy (SEM) revealed indications of a greater adhesion of the epoxy resin matrix to the CNT, most likely due to the covalent bonding.

  6. PVC/carbon nanotubes nanocomposites: evaluation of electrical resistivity and the residual solvent effect over the thermal properties of nanocomposites

    International Nuclear Information System (INIS)

    Araujo, Rogerio Gomes; Pires, Alfredo T.N.

    2013-01-01

    The procedure for obtaining nanocomposite by dispersing the nanoparticles in matrix polymer in solution with subsequent elimination of the solvent has been widely used, considering better efficiency in obtaining homogeneity of the final product. However, the presence of residual solvent may affect the nanocomposites in micro-and macroscopic properties of the product. The aim of this study was to evaluate the thermal properties of nanocomposites of poly(vinylchloride)/multi-walled carbon nanotube obtained from the polymer solution and dispersion of carbon nanotubes in tetrahydrofuran (THF), as well as the electrical resistivity of nanocomposites and the influence of residual solvent. The presence of residual tetrahydrofuran reduces the glass transition temperature (Tg) up to 26 °C, being independent of the amount of carbon nanotubes. The total elimination of the solvent is an important factor that does not induce changes in the properties of the polymeric matrix. The graft-COOH groups in the structure of the nanotubes leads to a considerable reduction of the electrical resistivity in ten orders of magnitude, from 0.4 %wt of nanotubes in the nanocomposite composition. (author)

  7. Sensitive electromechanical sensors using viscoelastic graphene-polymer nanocomposites.

    Science.gov (United States)

    Boland, Conor S; Khan, Umar; Ryan, Gavin; Barwich, Sebastian; Charifou, Romina; Harvey, Andrew; Backes, Claudia; Li, Zheling; Ferreira, Mauro S; Möbius, Matthias E; Young, Robert J; Coleman, Jonathan N

    2016-12-09

    Despite its widespread use in nanocomposites, the effect of embedding graphene in highly viscoelastic polymer matrices is not well understood. We added graphene to a lightly cross-linked polysilicone, often encountered as Silly Putty, changing its electromechanical properties substantially. The resulting nanocomposites display unusual electromechanical behavior, such as postdeformation temporal relaxation of electrical resistance and nonmonotonic changes in resistivity with strain. These phenomena are associated with the mobility of the nanosheets in the low-viscosity polymer matrix. By considering both the connectivity and mobility of the nanosheets, we developed a quantitative model that completely describes the electromechanical properties. These nanocomposites are sensitive electromechanical sensors with gauge factors >500 that can measure pulse, blood pressure, and even the impact associated with the footsteps of a small spider. Copyright © 2016, American Association for the Advancement of Science.

  8. Inorganic Metal Oxide/Organic Polymer Nanocomposites And Method Thereof

    Science.gov (United States)

    Gash, Alexander E.; Satcher, Joe H.; Simpson, Randy

    2004-11-16

    A synthetic method for preparation of hybrid inorganic/organic energetic nanocomposites is disclosed herein. The method employs the use of stable metal in organic salts and organic solvents as well as an organic polymer with good solubility in the solvent system to produce novel nanocomposite energetic materials. In addition, fuel metal powders (particularly those that are oxophilic) can be incorporated into composition. This material has been characterized by thermal methods, energy-filtered transmission electron microscopy (EFTEM), N.sub.2 adsoprtion/desorption methods, and Fourier-Transform (FT-IR) spectroscopy. According to these characterization methods the organic polymer phase fills the nanopores of the material, providing superb mixing of the component phases in the energetic nanocomposite.

  9. Free volume sizes in intercalated polyamide 6/clay nanocomposites

    DEFF Research Database (Denmark)

    Wiinberg, P.; Eldrup, Morten Mostgaard; Pedersen, N.J.

    2005-01-01

    The effect of incorporating modified clay into a polyamide 6 (PA6) matrix, on the free volume cavity sizes and the thermal and viscoelastic properties of the resulting nanocomposite, was studied with positron annihilation lifetime spectroscopy, differential scanning calorimetry and dynamic...... response of PA6/clay nanocomposites, as compared to unfilled PA6, pointed towards a changed mobility in the non-crystalline regions. At high concentrations of clay (> 19 wt%) an increase of the free volume cavity diameter was observed, indicating a lower chain packing efficiency in the PA6/clay...... nanocomposites. The increased free volume sizes were present both above and below the glass transition temperature of PA6. (c) 2005 Elsevier Ltd. All rights reserved....

  10. Characterization of synthesized polyurethane/montmorillonite nanocomposites foams

    International Nuclear Information System (INIS)

    Ansari, Farahnaz; Njuguna, James; Sachse, Sophia; Kavosh, Masoud; Michalowski, S; Pielichowski, Krzysztof

    2014-01-01

    Nanophased hybrid composites based on polyurethane/montmorillonite (PU/MMT) have been fabricated. The nanocomposite which was formed by the addition of a polyol premix with 4,4'-diphenylmethane diisocyanate to obtain nanophased polyurethane foams which were then used for fabrication of nanocomposite panels has been shown to have raised strength, stiffness and thermal insulation properties. The nanophased polyurethane foam was characterized by means of scanning electron microscope (SEM), transmission electron microscope (TEM) measurements and X-ray diffraction (XRD). TEM and SEM analysis indicated that nanophased particles are dispersed homogeneously in the polyurethane matrix on the nanometer scale indicating that PU/MMT is an intercalated nanocomposite with a 2-3 nm nanolayer thickness

  11. Structural and electrical properties of polyaniline/silver nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Afzal, Asma B; Akhtar, M J; Nadeem, M; Ahmad, M [Physics Division, PINSTECH, PO Nilore, Islamabad (Pakistan); Hassan, M M; Yasin, T [Department of Chemical and Material Engineering, PIEAS, Islamabad 45650 (Pakistan); Mehmood, M [National Centre for Nanotechnology, PIEAS, Islamabad 45650 (Pakistan)], E-mail: javeda@pinstech.org.pk, E-mail: javed06@yahoo.com

    2009-01-07

    Polyaniline (PANI)/Ag nanocomposites were prepared by separate synthesis of silver nanoparticles by inert gas condensation, incorporating in the 1-methyl-2-pyrrolidinone (NMP) solution of polyaniline emeraldine base (PANIEB) and then cast into films at 120 deg. C. X-ray diffraction confirmed the presence of {approx}67 nm silver nanoparticles in the polyaniline matrix. From the thermogravimetric analysis it is observed that the nanocomposite films have a higher degradation temperature than the pure PANI film. Scanning electron microscopy showed a uniform distribution, with spherical and granular morphology for low concentration of Ag nanoparticles, whereas for higher concentration (1.0% Ag) nanorods are formed. The impedance spectroscopic studies of NMP plasticized nanocomposite films suggest microphase separation into reduced and oxidized repeat units. Incorporation of silver nanoparticles in PANI reduces the charge trapping centres and increases the conducting channels, which causes a tenfold decrease in the real part of impedance.

  12. Silane coupling agent for enhanced epoxy-iron oxide nanocomposite

    Directory of Open Access Journals (Sweden)

    Hamdy M. Naguib

    2018-01-01

    Full Text Available In this study, silane-treated Fe2O3 nanoparticles were successfully prepared using (3-aminopropyl triethoxysilane (APTES. The chemical structure and morphology of the obtained nanoparticles were investigated by several analysis techniques including FTIR, XRD, TEM and DLS. Both of untreated Fe2O3 (IO and silane-treated Fe2O3 (SIO nanoparticles were used in the preparation of epoxy nanocomposites with 5% by weight fraction. FTIR and XRD approved that SIO was successfully prepared with highly crystalline structure. TEM and DLS indicated the good dispersion of treated nanoparticles in the nanocomposite matrix, also the average particle size of nanofiller decreased to ∼200 nm after silane treatment. The dynamic properties for the prepared nanocomposites were studied using DMA and confirmed by nanoindentation technique. The results indicated that silane-treated nanoparticles can improve the hardness and Tg by 87.5% and 5 °C respectively at 5% weight fraction.

  13. Structural and electrical properties of polyaniline/silver nanocomposites

    International Nuclear Information System (INIS)

    Afzal, Asma B; Akhtar, M J; Nadeem, M; Ahmad, M; Hassan, M M; Yasin, T; Mehmood, M

    2009-01-01

    Polyaniline (PANI)/Ag nanocomposites were prepared by separate synthesis of silver nanoparticles by inert gas condensation, incorporating in the 1-methyl-2-pyrrolidinone (NMP) solution of polyaniline emeraldine base (PANIEB) and then cast into films at 120 deg. C. X-ray diffraction confirmed the presence of ∼67 nm silver nanoparticles in the polyaniline matrix. From the thermogravimetric analysis it is observed that the nanocomposite films have a higher degradation temperature than the pure PANI film. Scanning electron microscopy showed a uniform distribution, with spherical and granular morphology for low concentration of Ag nanoparticles, whereas for higher concentration (1.0% Ag) nanorods are formed. The impedance spectroscopic studies of NMP plasticized nanocomposite films suggest microphase separation into reduced and oxidized repeat units. Incorporation of silver nanoparticles in PANI reduces the charge trapping centres and increases the conducting channels, which causes a tenfold decrease in the real part of impedance.

  14. Synthesis of copper polyacrylate nanocomposites by gamma irradiation

    International Nuclear Information System (INIS)

    Casalme, Loida Olores

    2005-04-01

    This research involves the synthesis of copper nanoparticles with controlled size by the application of gamma radiation with varying polyacrylic acid (PAA) and CuSO 4 concentration. An alternative and convenient method was done which employs Co 60 irradiation of solutions of copper salt and PAA with irradiation dose of 1.6, 3.6, 6.4, and 9.2 MRad. The effect of polymer and copper sulfate's initial concentrations as well as the effect of the presence of alcohol as radical scavenger and the presence of ethylenediaminetetraacetic acid as stabilizer were evaluated. Characterization of nanocomposite properties such as plasmon resonance band, fluorescence, and particle morphology and size were determined. Layer-by-layer assembly of Cu-PAA nanocomposites and polydiallyl dimethyl ammonium chloride (PDDA) was also constructed. Stability of the synthesized copper-PAA nanocomposites in terms of the disappearance of plasmon band with time was evaluated. (Author)

  15. Optical properties of photopolymerizable nanocomposites containing nanosized molecular sieves

    International Nuclear Information System (INIS)

    Naydenova, I; Leite, E; Babeva, Tz; Pandey, N; Baron, T; Martin, S; Toal, V; Yovcheva, T; Sainov, S; Mintova, S

    2011-01-01

    Acrylamide-based photopolymerizable nanocomposites containing three types of nanosized crystals with controlled microporosity, Silicalite-1 (MFI-structure), AlPO-18 (AEI-structure) and Beta (BEA-structure) are studied. The influence of the porous nanoparticles on the average refractive index, optical scattering and holographic recording properties of the nanocomposite are characterized. The redistribution of nanoparticles as a result of the holographic recording in the layers is investigated by Raman spectroscopy. It is observed that in all three nanocomposites the nanoparticles are redistributed according to the illuminating light pattern. This redistribution improves the refractive index modulation only in the case of the MFI nanoparticles, while no improvement is observed in AEI and BEA doped layers. The results can be explained by the hydrophobic/hydrophilic nature of the nanoparticles and their interactions, or absence of interactions, with the host photopolymer

  16. Transparent bulk-size nanocomposites with high inorganic loading

    International Nuclear Information System (INIS)

    Chen, Shi; Gaume, Romain

    2015-01-01

    With relatively high nanoparticle loading in polymer matrices, hybrid nanocomposites made by colloidal dispersion routes suffer from severe inhomogeneous agglomeration, a phenomenon that deteriorates light transmission even when the refractive indices of the inorganic and organic phases are closely matched. The dispersion of particles in a matrix is of paramount importance to obtain composites of high optical quality. Here, we describe an innovative, yet straightforward method to fabricate monolithic transparent hybrid nanocomposites with very high particle loading and high refractive index mismatch tolerance between the inorganic and organic constituents. We demonstrate 77% transmission at 800 nm in a 2 mm-thick acrylate polymer nanocomposite containing 61 vol. % CaF 2 nanoparticles. Modeling shows that similar performance could easily be obtained with various inorganic phases relevant to a number of photonic applications

  17. Evaluation of impact strength of polyamide 6/bentonite clay nanocomposites

    International Nuclear Information System (INIS)

    Paz, Rene A.; Leite, Amanda M.D.; Medeirosa, Vanessa da N.; Araujo, Edcleide M.; Melo, Tomas J.A.; Pessan, Luiz A.

    2010-01-01

    Nanocomposites of polymer/clay have had much attention in recent years, particularly those developed with layered silicates due to the need of engineering materials more efficient than pure polymers for certain applications. The level of exfoliation of layered silicates in crystalline structure of polymer matrices has been studied and has been observed that they affect the crystalline behavior and the physical and mechanical properties. In this study, nanocomposites of polyamide 6 were obtained by the melt intercalation method, using a regional bentonite modified with a quaternary ammonium salt in an amount of 3% by weight. XRD results showed that incorporation of salt among the layers of clay, making it organophilic and obtaining exfoliated and/or partially exfoliated structures. The impact properties of the nanocomposites showed inferior in relation to pure polyamide, in other words, lost of toughness. (author)

  18. Flexible carbon nanotube nanocomposite sensor for multiple physiological parameter monitoring

    KAUST Repository

    Nag, Anindya

    2016-10-16

    The paper presents the design, development, and fabrication of a flexible and wearable sensor based on carbon nanotube nanocomposite for monitoring specific physiological parameters. Polydimethylsiloxane (PDMS) was used as the substrate with a thin layer of a nanocomposite comprising functionalized multi-walled carbon nanotubes (MWCNTs) and PDMS as electrodes. The sensor patch functionalized on strain-sensitive capacitive sensing from interdigitated electrodes which were patterned with a laser on the nanocomposite layer. The thickness of the electrode layer was optimized regarding strain and conductivity. The sensor patch was connected to a monitoring device from one end and attached to the body on the other for examining purposes. Experimental results show the capability of the sensor patch used to detect respiration and limb movements. This work is a stepping stone of the sensing system to be developed for multiple physiological parameters.

  19. Fabrication and electrochemical performance of graphene—ZnO nanocomposites

    International Nuclear Information System (INIS)

    Li Zhen-Peng; Men Chuan-Ling; Wang Wan; Cao Jun

    2014-01-01

    Graphene—ZnO nanocomposites were synthesized successfully through a one-step solvothermal approach. The morphology, structure, and composition of the prepared nanocomposites were investigated by scanning electron microscopy (SEM), transmission electron microscope (TEM), laser micro Raman spectroscopy, and Fourier transform infra-red spectroscopy (FT-IR). The outcomes confirmed that this approach is comparatively steady, practicable, and operable compared with other reported methods. The electrochemical performance of the graphene-ZnO electrodes was analyzed through cyclic voltammetry, altering-current (AC) impedance, and chronopotentiometry tests. The graphene—ZnO electrodes exhibited an improved electrode performance with higher specific capacitance (115 F·g −1 ), higher electrochemical stability, and higher energy density than the graphene electrodes and most reported graphene—ZnO electrodes. Graphene—ZnO nanocomposites have a steady reversible charge/discharge behavior, which makes them promising candidates for electrochemical capacitors (ECs). (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  20. Surface characterization of polyethylene terephthalate/silica nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Parvinzadeh, Mazeyar, E-mail: mparvinzadeh@gmail.com [Department of Textile, Islamic Azad University, Science and Research Branch, Tehran (Iran, Islamic Republic of); Moradian, Siamak [Department of Polymer and Color Engineering, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Rashidi, Abosaeed [Department of Textile, Islamic Azad University, Science and Research Branch, Tehran (Iran, Islamic Republic of); Yazdanshenas, Mohamad-Esmail [Department of Textile, Islamic Azad University, Yazd Branch, Yazd (Iran, Islamic Republic of)

    2010-02-15

    Poly(ethylene terephthalate) (PET) based nanocomposites containing hydrophilic (i.e. Aerosil 200 or Aerosil TT 600) or hydrophobic (i.e. Aerosil R 972) nano-silica were prepared by melt compounding. Influence of nano-silica type on surface properties of the resultant nanocomposites was investigated by the use of Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), contact angle measurement (CAM), scanning electron microscopy (SEM) and reflectance spectroscopy (RS). The possible interaction between nano-silica particles and PET functional groups at bulk and surface were elucidated by transmission FTIR and FTIR-ATR spectroscopy, respectively. AFM studies of the resultant nanocomposites showed increased surface roughness compared to pure PET. Contact angle measurements of the resultant PET composites demonstrated that the wettability of such composites depends on surface treatment of the particular nano-silica particles used. SEM images illustrated that hydrophilic nano-silica particles tended to migrate to the surface of the PET matrix.