ENHANCING DIRECT ELECTRON TRANSFER OF GLUCOSE OXIDASE USING A GOLD NANOPARTICLE |TITANATE NANOTUBE NANOCOMPOSITE ON A BIOSENSOR

International Nuclear Information System (INIS)

Zhao, Ruoxia; Liu, Xiaoqiang; Zhang, Jiamei; Zhu, Jie; Wong, Danny K.Y.

2015-01-01

ABSTRACT: In this paper, we have developed a gold nanoparticle (GNP) decorated titanate nanotubes (TNT) nanocomposite that aids in the direct electron transfer of a large enzyme, such as glucose oxidase (GOD), in which the electroactive site of flavin adenine dinucleotide is deeply buried within the enzyme. The ionic liquid, brominated 1-decyl-3-methyl imidazole, was used to immobilise the nanocomposite and the enzyme on a glassy carbon electrode to further aid in the electron transfer between GOD and the electrode surface. Nafion was also added to anchor the biosensor scaffold. Initially, the tubiform geometry of titanate nanomaterials and the GNP-TNT nanocomposite was confirmed by microscopic and spectroscopic techniques before glucose oxidase was entrapped in the nanocomposite. Based on voltammetric results, this biosensor showed a strong electrocatalytic capability towards glucose (with a heterogeneous electron transfer rate constant of 7.1 s −1 at 180 mV s −1 ) and the calibration for glucose exhibited a high sensitivity (5.1 μA mM −1 ) and a wide linear range (0.01–1.2 mM). These results demonstrated superior analytical performance of our biosensor over others fabricated using bulkier TiO 2 nanoparticles or nanobundles, which could be attributed to a high degree of biocompatibility to glucose oxidase and electrical conductivity of the nanocomposite

High-performance polyimide nanocomposites with core-shell AgNWs@BN for electronic packagings

Energy Technology Data Exchange (ETDEWEB)

Zhou, Yongcun; Liu, Feng, E-mail: liufeng@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi' an Shaanxi 710072 (China)

2016-08-22

The increasing density of electronic devices underscores the need for efficient thermal management. Silver nanowires (AgNWs), as one-dimensional nanostructures, possess a high aspect ratio and intrinsic thermal conductivity. However, high electrical conductivity of AgNWs limits their application for electronic packaging. We synthesized boron nitride-coated silver nanowires (AgNWs@BN) using a flexible and fast method followed by incorporation into synthetic polyimide (PI) for enhanced thermal conductivity and dielectric properties of nanocomposites. The thinner boron nitride intermediate nanolayer on AgNWs not only alleviated the mismatch between AgNWs and PI but also enhanced their interfacial interaction. Hence, the maximum thermal conductivity of an AgNWs@BN/PI composite with a filler loading up to 20% volume was increased to 4.33 W/m K, which is an enhancement by nearly 23.3 times compared with that of the PI matrix. The relative permittivity and dielectric loss were about 9.89 and 0.015 at 1 MHz, respectively. Compared with AgNWs@SiO{sub 2}/PI and Ag@BN/PI composites, boron nitride-coated core-shell structures effectively increased the thermal conductivity and reduced the permittivity of nanocomposites. The relative mechanism was studied and discussed. This study enables the identification of appropriate modifier fillers for polymer matrix nanocomposites.

Nano-composite of PtRu alloy electrocatalyst and electronically conducting polymer for use as the anode in a direct methanol fuel cell

Energy Technology Data Exchange (ETDEWEB)

Jongho Choi; Kyungwon Park; Hyekyung Lee; Youngmin Kim; Jaesuk Lee; Yungeun Sung [Kwangju Inst. of Science and Technology, Dept. of Materials Science and Engineering, Gwangju (Korea)

2003-08-15

Nano-composites comprised of PtRu alloy nanoparticles and an electronically conducting polymer for the anode electrode in direct methanol fuel cell (DMFC) were prepared. Two conducting polymers of poly(N-vinyl carbazole) and poly(9-(4-vinyl-phenyl)carbazole) were used for the nano-composite electrodes. Structural analyses were carried out using Fourier transform nuclear magnetic resonance spectroscopy, AC impedance spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Electrocatalytic activities were investigated by voltammetry and chronoamperometry in a 2 M CH{sub 3}OH/{sub 0.5} M H{sub 2}SO{sub 4} solution and the data compared with a carbon-supported PtRu electrode. XRD patterns indicated good alloy formation and nano-composite formation was confirmed by TEM. Electrochemical measurements and DMFC unit-cell tests indicate that the nano-composites could be useful in a DMFC, but its performance would be slightly lower than that of a carbon-supported electrode. The interfacial property between the PtRu-polymer nano-composite anode and the polymer electrolyte was good, as evidenced by scanning electron microscopy. For better performance in a DMFC, a higher electric conductivity of the polymer and a lower catalyst loss are needed in nano-composite electrodes. (Author)

Effective Electron Transfer Pathway of the Ternary TiO2/RGO/Ag Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

Directory of Open Access Journals (Sweden)

Hongwei Tian

2017-05-01

Full Text Available Mesoporous TiO2/reduced graphene oxide/Ag (TiO2/RGO/Ag ternary nanocomposite with an effective electron transfer pathway is obtained by an electrostatic self-assembly method and photo-assisted treatment. Compared with bare mesoporous TiO2 (MT and mesoporous TiO2/RGO (MTG, the ternary mesoporous TiO2/RGO/Ag (MTGA nanocomposite exhibited superior photocatalytic performance for the degradation of methylene blue (MB under visible light, and the degradation rate reached 0.017 min−1, which was 3.4-times higher than that of MTG. What is more, the degradation rate of MTGA nanocomposite after three cycle times is 91.2%, and the composition is unchanged. In addition, we found that the OH•, h+ and especially O2•− contribute to the high photocatalytic activity of MTGA for MB degradation. It is proposed that Ag nanoparticles can form the local surface plasmon resonance (LSPR to absorb the visible light and distract the electrons into MT, and RGO can accept the electrons from MT to accelerate the separation efficiency of photogenerated carriers. The establishment of MTGA ternary nanocomposite makes the three components act synergistically to enhance the photocatalytic performance.

Effect of electron beam irradiation on the mechanical and thermal properties of intumescent flame retarded ethylene-vinyl acetate copolymer/organically modified montmorillonite nanocomposites

International Nuclear Information System (INIS)

Wang Bibo; Song Lei; Hong Ningning; Tai Qilong; Lu Hongdian; Hu Yuan

2011-01-01

Ethylene-vinyl acetate copolymer (EVA) flame retarded by a combination of intumescent flame retardants (IFR) and organically modified montmorillonite (OMMT) have been crosslinked by high-energy electron beam irradiation. The structure was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The effects of electron beam irradiation on the thermal, mechanical and dynamic mechanical properties of the irradiated EVA nanocomposites were investigated. The XRD and TEM results demonstrated that the OMMT was well dispersed in the EVA nanocomposites. The LOI and UL-94 results showed that a synergistic effect on the flame retardancy of EVA nanocomposite existed between the IFR and OMMT. With the addition of 1 wt% OMMT and 24 wt% IFR, the LOI value of EVA/IFR/OMMT nanocomposite increased from 30.5 % to 33.5 %. The mechanical properties of the irradiated EVA nanocomposite were evidently improved at 160 kGy dosage with the increase in the tensile strength to 18.5 MPa. Thermal oxidative degradation of the flame-retardant EVA/IFR/OMMT nanocomposites was characterized by thermogravimetric analysis/infrared spectrometry (TG-IR) and real-time Fourier transformed infrared spectroscopy (RT-FTIR). - Highlights: → The results signify a synergistic effect between OMMT and IFR in the EVA matrix. → The XRD and TEM indicate that the OMMT is well dispersed in the EVA matrix. → The Tg of EVA nanocomposites increase with the increase in the irradiation dose. → The GS peak of EVA composites decrease with the increase in the irradiation dose.

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...

Scanning and transmission electron microscopy investigation of multiwall carbon nanotube/nickel oxide nanocomposite thin films

CSIR Research Space (South Africa)

Roro, Kittessa T

2011-12-01

Full Text Available Owing to their unique electronic and optical properties, nanocomposite thin films are widely used for converting solar radiation therapy into other conventional energy forms, such as heat and electricity. Carbon nanotube-based composites which can...

Organic/inorganic nanocomposites of ZnO/CuO/chitosan with improved properties

Energy Technology Data Exchange (ETDEWEB)

Ma, Xingfa, E-mail: xingfamazju@aliyun.com [School of Environmental and Material Engineering, Center of Advanced Functional Materials, Yantai University, Yantai, 264005 (China); State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou, 310027 (China); Zhang, Bo; Cong, Qin; He, Xiaochun; Gao, Mingjun [School of Environmental and Material Engineering, Center of Advanced Functional Materials, Yantai University, Yantai, 264005 (China); Li, Guang [National Laboratory of Industrial Control Technology, Institute of Cyber-Systems and Control, Zhejiang University, Hangzhou, 310027 (China)

2016-08-01

To extend the visible light response of ZnO, ZnO/CuO heterostructured nanocomposite was synthesized by a hydrothermal approach. At the same time, chitosan (Ch) is considered as a very promising natural polymer. It holds not only abundant resource and low cost, but also has excellent adsorption properties to a broad range of organic pollutants and some heavy metal ions. To improve the adsorption properties of ZnO/CuO nanocomposite, ZnO/CuO/chitosan organic-inorganic composites were prepared with precipitation method. The as-prepared nanocomposites were characterized by TEM (Transmission electron microscopy), SAED pattern (Selected Area Electron Diffraction), SEM (scanning electron microscopy), UV–Vis (Ultraviolet–visible spectroscopy), PL (Photoluminescence), XRD (X-ray diffraction), TGA (Thermo Gravimetric Analyzer), Fourier transform infrared spectroscopy spectra (FTIR) et al. To examine the surface and interface properties of nanocomposites, chemical prototype sensor arrays were constructed based on ZnO, ZnO/CuO, ZnO/Cu{sub 2}O, ZnO/CuO/chitosan, ZnO/Cu{sub 2}O/chitosan nanocomposites and QCM (quartz crystal microbalance) arrays devices. The adsorption response behaviors of the sensor arrays to some typical volatile compounds were examined under similar conditions. The results indicated that with comparison to ZnO nanostructure, the ZnO/CuO nanocomposite exhibited enhanced adsorption properties to some typical volatile compounds greatly, and the adsorption properties of ZnO/CuO/chitosan are much better than that of ZnO/CuO nanocomposite. The adsorption of ZnO/CuO system is super to that of ZnO/Cu{sub 2}O. Therefore, ZnO/CuO/chitosan nanocomposite not only showed broadening visible light response, but also possessed of excellent adsorption properties, and has good potential applications in photocatalysts, chemical sensors, biosensors, self-cleaning coating fields et al. - Highlights: • ZnO/CuO nanocomposites exhibited good response in near whole visible

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...

Scanning Electron Microscopic Studies of Microwave Sintered Al-SiC Nanocomposites and Their Properties

Directory of Open Access Journals (Sweden)

M. A. Himyan

2018-01-01

Full Text Available Al-metal matrix composites (AMMCs reinforced with diverse volume fraction of SiC nanoparticles were synthesized using microwave sintering process. The effects of the reinforcing SiC particles on physical, microstructure, mechanical, and electrical properties were studied. The phase, microstructural, and surface analyses of the composites were systematically conducted using X-ray diffraction (XRD, scanning electron microscope (SEM, and surface profilometer techniques, respectively. The microstructural examination revealed the homogeneous distribution of SiC particles in the Al matrix. Microhardness and compressive strength of nanocomposites were found to be increasing with the increasing volume fraction of SiC particles. Electrical conductivity of the nanocomposites decreases with increasing the SiC content.

Improvement of mechanical and thermal properties of high energy electron beam irradiated HDPE/hydroxyapatite nano-composite

Science.gov (United States)

Mohammadi, M.; Ziaie, F.; Majdabadi, A.; Akhavan, A.; Shafaei, M.

2017-01-01

In this research work, the nano-composites of high density polyethylene/hydroxyapatite samples were manufactured via two methods: In the first method, the granules of high density polyethylene and nano-structure hydroxyapatite were processed in an internal mixer to prepare the nano-composite samples with a different weight percentage of the reinforcement phase. As for the second one, high density polyethylene was prepared in nano-powder form in boiling xylene. During this procedure, the hydroxyapatite nano-powder was added with different weight percentages to the solvent to obtain the nano-composite. In both of the procedures, the used hydroxyapatite nano-powder was synthesized via hydrolysis methods. The samples were irradiated under 10 MeV electron beam in 70-200 kGy of doses. Mechanical, thermal and morphological properties of the samples were investigated and compared. The results demonstrate that the nano-composites which we have prepared using nano-polyethylene, show better mechanical and thermal properties than the composites prepared from normal polyethylene granules, due to the better dispersion of nano-particles in the polymer matrix.

Transmission Electron Microscopy of Single Wall Carbon Nanotube/Polymer Nanocomposites: A First-Principles Study

Science.gov (United States)

Sola, Francisco; Xia, Zhenhai; Lebrion-Colon, Marisabel; Meador, Michael A.

2012-01-01

The physics of HRTEM image formation and electron diffraction of SWCNT in a polymer matrix were investigated theoretically on the basis of the multislice method, and the optics of a FEG Super TWIN Philips CM 200 TEM operated at 80 kV. The effect of nanocomposite thickness on both image contrast and typical electron diffraction reflections of nanofillers were explored. The implications of the results on the experimental applicability to study dispersion, chirality and diameter of nanofillers are discussed.

Electronic Resource Management and Design

Science.gov (United States)

Abrams, Kimberly R.

2015-01-01

We have now reached a tipping point at which electronic resources comprise more than half of academic library budgets. Because of the increasing work associated with the ever-increasing number of e-resources, there is a trend to distribute work throughout the library even in the presence of an electronic resources department. In 2013, the author…

Morphological and crystalline structural characteristics of PEDOT™/TiO{sub 2} nanocomposites for applications towards technology in electronic devices

Energy Technology Data Exchange (ETDEWEB)

Ashery, A. [Solid State Physics Department, Physics Division, National Research Center, Dokki, Giza, 12311 (Egypt); Said, G. [Physics Department, Faculty of Science, Fayoum University, Fayoum (Egypt); Arafa, W.A. [Chemistry Department, Faculty of Science, Fayom University, Fayoum (Egypt); Gaballah, A.E.H. [Research Scholar, Physics Department, Faculty of Science, Fayoum University (Egypt); Farag, A.A.M., E-mail: alaafaragg@gmail.com [Department of Physics, Faculty of Science and Arts, Aljouf University, Aljouf (Saudi Arabia); Thin Film Laboratory, Department of Physics, Faculty of Education, Ain Shams University, Roxy, 11757, Cairo (Egypt)

2016-06-25

Nanocomposites of Poly(3,4-ethylenedioxythiophene), Tetra Methacrylate (PEDOT™)/TiO{sub 2} were prepared and characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Scanning electron microscopy indicated highly dense surface morphology of the prepared samples. Transmission electron microscopy images indicated that the prepared samples have particle size comparable with those obtained by X-ray diffraction results. The crystallite sizes, lattice strain and other related physical parameters were calculated by using X-ray peak broadening analysis. Optical constants such as extinction coefficient and refractive index as well as dielectric constants were calculated for PEDOT™/TiO{sub 2} nanocomposite film using spectrophotometric measurements of both transmittance and reflectance in the wavelength range of 300–2400 nm. PEDOT™/TiO{sub 2} nanocomposite films/n-Si diodes were prepared by spin coating method. The electrical properties of the diodes were investigated at different temperatures in the range 300–375 K. The prepared diode showed a rectification characteristics and the rectification ratio was studied as a function of voltage at different temperatures. Temperature dependence of both ideality factor and barrier height was also investigated. High values of ideality factor confirmed the abnormality characteristics of the prepared diodes as compared to the conventional behavior of ideal diode. - Highlights: • Nanocomposite TiO{sub 2}- PEDOT™ films were prepared by sol gel technique. • A remarkable dependence of n and dispersion parameters on film thickness. • Anomalous behavior of n was explained by multi-oscillation model. • Energy gap of PEDOT™ doped TiO{sub 2} is lower than those for undoped TiO{sub 2}. • Rectification characteristics were observed for PEDOT™-doped TiO{sub 2}/n-Si.

Synthesis and characterization of silver/diatomite nanocomposite by electron beam irradiation

Science.gov (United States)

Hanh, Truong Thi; Thu, Nguyen Thi; Quoc, Le Anh; Hien, Nguyen Quoc

2017-10-01

Silver nanoparticles (AgNPs) with diameter about 9 nm were deposited on diatomite by irradiation under electron beam of diatomite suspension containing 10 mM AgNO3 in 1% chitosan solution, at the dose of 20.2 kGy. The AgNPs/diatomite nanocomposite was characterized by UV-Vis spectroscopy, TEM image and energy dispersive X-ray spectroscopy (EDX). The antibacterial activity of the AgNPs/diatomite against E. coli and S. aureus was evaluated by reduction of bacterial colonies on spread plates and inhibition zone diameter on diffusion disks.

Electronic and Magnetic Properties of Transition-Metal Oxide Nanocomposites: A Tight-Binding Modeling at Mesoscale

Science.gov (United States)

Tai, Yuan-Yen; Zhu, Jian-Xin

Transition metal oxides (TMOs) exhibit many emergent phenomena ranging from high-temperature superconductivity and giant magnetoresistance to magnetism and ferroelectricity. In addition, when TMOs are interfaced with each other, new functionalities can arise, which are absent in individual components. In this talk, I will present an overview on our recent efforts in theoretical understanding of the electronic and magnetic properties TMO nanocomposites. In particular, I will introduce our recently developed tight-binding modeling of these properties arising from the interplay of competing interactions at the interfaces of planar and pillar nanocomposites. Our theoretical tool package will provide a unique capability to address the emergent phenomena in TMO nanocomposites and their mesoscale response to such effects like strain and microstructures at the interfaces, and ultimately help establish design principles of new multifunctionality with TMOs. This work was carried out under the auspices of the National Nuclear Security Administration of the U.S. Department of Energy at LANL under Contract No. DE-AC52-06NA25396, and was supported by the LANL LDRD Program.

Thermal and mechanical properties of palm oil-based polyurethane acrylate/clay nanocomposites prepared by in-situ intercalative method and electron beam radiation

Energy Technology Data Exchange (ETDEWEB)

Salih, A. M. [Department of Chemistry, Faculty of Science, University Putra Malaysia 43400, UPM, Serdang, Selangor, Malaysia and Department of Radiation Processing, Sudan Atomic Energy Commission, Khartoum 1111 (Sudan); Ahmad, Mansor Bin; Ibrahim, Nor Azowa [Department of Chemistry, Faculty of Science, University Putra Malaysia 43400, UPM, Serdang, Selangor (Malaysia); Dahlan, Khairul Zaman Hj Mohd [Polycomposite Sdn Bhd, No.75-2, Jalan TKS 1, Taman Kajang Sentral, 43000 Kajang, Selangor (Malaysia); Tajau, Rida [Radiation Processing Technology Division, Nuclear Malaysia, Bangi, 43000 Kajang, Selangor (Malaysia); Mahmood, Mohd Hilmi [No. 107, Jalan 2, Taman Kajang Baru, Sg Jelok, 43000 Kajang, Selangor (Malaysia); Yunus, Wan Md. Zin Wan [Department of Chemistry, Centre for Defence Foundation Studies, National Defence University of Malaysia, 57000, Sungai Besi Camp, Kuala Lumpur (Malaysia)

2014-02-12

Palm oil based-polyurethane acrylate (POBUA)/clay nanocomposites were prepared via in-situ intercalative polymerization using epoxidized palm oil acrylate (EPOLA) and 4,4' methylene diphenyl diisocyante (MDI). Organically modified Montmorillonite (ODA-MMT) was incorporated in EPOLA (1, 3 and 5%wt), and then subjected to polycondensation reaction with MDI. Nanocomposites solid films were obtained successfully by electron beam radiation induced free radical polymerization (curing). FTIR results reveal that the prepolymer was obtained successfully, with nanoclay dispersed in the matrix. The intercalation of the clay in the polymer matrix was investigated by XRD and the interlayer spacing of clay was found to be increased up to 37 Å, while the structure morphology of the nanocomposites was investigated by TEM and SEM. The nanocomposites were found to be a mixture of exfoliated and intercalated morphologies. The thermal stability of the nanocomposites was significantly increased by incorporation of nanoclay into the polymer matrix. DSC results reveal that the Tg was shifted to higher values, gradually with increasing the amount of filler in the nanocomposites. Tensile strength and Young's modulus of the nanocomposites showed remarkable improvement compared to the neat POBUA.

Thermal and mechanical properties of palm oil-based polyurethane acrylate/clay nanocomposites prepared by in-situ intercalative method and electron beam radiation

International Nuclear Information System (INIS)

Salih, A. M.; Ahmad, Mansor Bin; Ibrahim, Nor Azowa; Dahlan, Khairul Zaman Hj Mohd; Tajau, Rida; Mahmood, Mohd Hilmi; Yunus, Wan Md. Zin Wan

2014-01-01

Palm oil based-polyurethane acrylate (POBUA)/clay nanocomposites were prepared via in-situ intercalative polymerization using epoxidized palm oil acrylate (EPOLA) and 4,4' methylene diphenyl diisocyante (MDI). Organically modified Montmorillonite (ODA-MMT) was incorporated in EPOLA (1, 3 and 5%wt), and then subjected to polycondensation reaction with MDI. Nanocomposites solid films were obtained successfully by electron beam radiation induced free radical polymerization (curing). FTIR results reveal that the prepolymer was obtained successfully, with nanoclay dispersed in the matrix. The intercalation of the clay in the polymer matrix was investigated by XRD and the interlayer spacing of clay was found to be increased up to 37 Å, while the structure morphology of the nanocomposites was investigated by TEM and SEM. The nanocomposites were found to be a mixture of exfoliated and intercalated morphologies. The thermal stability of the nanocomposites was significantly increased by incorporation of nanoclay into the polymer matrix. DSC results reveal that the Tg was shifted to higher values, gradually with increasing the amount of filler in the nanocomposites. Tensile strength and Young's modulus of the nanocomposites showed remarkable improvement compared to the neat POBUA

Electron transport in erbium arsenide:indium gallium(aluminum)arsenide metal/semiconductor nanocomposites for thermoelectric power generation

Science.gov (United States)

Bahk, Je-Hyeong

Electron transport in thin film ErAs:InGa(Al)As metal/semiconductor nanocomposite materials grown by molecular beam epitaxy is investigated experimentally and theoretically for efficient thermoelectric power generation. Thermoelectric properties such as the Seebeck coefficient, the electrical conductivity, and the thermal conductivity are measured for the various compositions of the material up to 840 K. A special sample preparation method is proposed to protect the thin films from damage and/or decomposition, and prevent the parasitic substrate conduction effect during the high temperature measurements. The sample preparation method includes surface passivation, high temperature metallization with a diffusion barrier, and the covalent oxide bonding technique for substrate removal. The experimental results for the nanocomposite materials are analyzed using the Boltzmann transport equation under the relaxation time approximation. The scattering characteristics of free electrons in the InGa(Al)As is defined by four major scattering mechanisms such as the polar optical phonon scattering, the ionized impurity scattering, the alloy scattering, and the acoustic phonon deformation potential scattering. Combining these scattering mechanisms, the electron transport model successfully fits the temperature-dependent thermoelectric properties of Si-doped InGaAlAs materials, and predicts the figure of merits at various doping levels in various Al compositions. The nanoparticle-electron interaction is modeled as a momentum scattering for free electrons caused by the electrostatic potential perturbation around nanoparticles and the band offset at the interface. The ErAs nanoparticles are assumed to be semi-metals that can donate electrons to the matrix, and positively charged after the charge transfer to build up the screened coulomb potential outside them. The nanoparticle scattering rate is calculated for this potential profile using the partial wave method, and used to analyze

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 ...

Sensors on Textile Fibres Based on Ag/a-C:H:O Nanocomposite Coatings

Directory of Open Access Journals (Sweden)

Martin Drabik

2013-08-01

Full Text Available In this contribution we present a study of the vacuum deposition process of metal/plasma polymer nanocomposite thin films monitored using plasma diagnostics (optical emission spectroscopy. We investigate\tthe\telectrical\tproperties\tof\tthe nanocomposite structures suitable for their application as\thumidity\tsensors.\tFurthermore,\tthe\tfilm microstructure is characterized by transmission electron microscopy and electron diffraction analysis. The amount of silver in the nanocomposite is evaluated using inductively coupled plasma optical emission spectrometry and the morphology of the structured\tsystem\tof\tmetal\telectrodes\tand nanocomposite films on monofilament textile fibres is visualized using scanning electron microscopy. Ageing of nanocomposite coatings and the influence of an aqueous environment on their internal structure and properties are discussed.

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.

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 ...

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

Transmission electron microscopy of polyhydroxybutyrate-co-valerate (PHBV)/nanocrystalline cellulose (NCC) bio-nanocomposite prepared using cryo-ultramicrotomy

Science.gov (United States)

Ismarul, N. I.; Engku, A. H. E. U.; Siti, N. K.; Tay, K. Y.

2017-12-01

Environmental issues on disposal and end-of-life for product made from synthetic petroleum-derived polymers have gained increasing attention from materials scientist to search for new materials with similar physical and mechanical properties but environmental friendly in a way that they are renewable and biodegradable as well. This work is to study the effect of nanocrystalline cellulose in improving the thermal stability of polyhydroxybutyrate-co-valerate biopolymer for high temperature processing of packaging material. 10 % w/w PHBV-NCC bio-nanocomposite feedstock pellet prepared using RONDOL minilab compounder was used as the sample for the preparation of Transmission Electron Microscopy (TEM) sample. RMC Cryo-Ultramicrotomy equipment was used to prepare the ultra-thin slice of the bio-nanocomposite pellet under liquid nitrogen at - 60 °C. Diamond knife was used to slice off about 80-100 nm ultra-thin bio-nanocomposite films and was transferred into the lacey carbon film coated grid using cooled sugar solution. A few drops of phosphotungstic acid was used as negative stain to improve the contrast during the TEM analysis. HITACHI TEM systems was used to obtain the TEM micrograph of PHBV-NCC bio-nanocomposite using 80kV accelerating voltage. A well dispersed NCC in PHBV matrix, ranging from 5 to 25 nm in width was observed.

Microstructure and Mechanical Properties of Graphene-Reinforced Titanium Matrix/Nano-Hydroxyapatite Nanocomposites.

Science.gov (United States)

Li, Feng; Jiang, Xiaosong; Shao, Zhenyi; Zhu, Degui; Zhu, Minhao

2018-04-16

Biomaterial composites made of titanium and hydroxyapatite (HA) powder are among the most important biomedicalmaterials due to their good mechanical properties and biocompatibility. In this work, graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites were prepared by vacuum hot-pressing sintering. The microstructure and mechanical properties of graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were systematically investigated. Microstructures of the nanocomposites were examined by X-ray diffraction (XRD), back scattered electron imaging (BSE), scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS), electron probe microanalyzer (EPMA), and transmission electron microscope (TEM). The mechanical properties were determined from microhardness, shear strength, and compressive strength. Results showed that during the high-temperature sintering process, complex chemical reactions occurred, resulting in new phases of nucleation such as Ca₃(PO₄)₂, Ti x P y , and Ti₃O.The new phases, which easily dropped off under the action of external force, could hinder the densification of sintering and increase the brittleness of the nanocomposites. Results demonstrated that graphene had an impact on the microstructure and mechanical properties of the nanocomposites. Based on the mechanical properties and microstructure of the nanocomposites, the strengthening and fracture mechanisms of the graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were analyzed.

Microstructure and Mechanical Properties of Graphene-Reinforced Titanium Matrix/Nano-Hydroxyapatite Nanocomposites

Directory of Open Access Journals (Sweden)

Feng Li

2018-04-01

Full Text Available Biomaterial composites made of titanium and hydroxyapatite (HA powder are among the most important biomedicalmaterials due to their good mechanical properties and biocompatibility. In this work, graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites were prepared by vacuum hot-pressing sintering. The microstructure and mechanical properties of graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were systematically investigated. Microstructures of the nanocomposites were examined by X-ray diffraction (XRD, back scattered electron imaging (BSE, scanning electron microscope (SEM equipped with energy dispersive spectrometer (EDS, electron probe microanalyzer (EPMA, and transmission electron microscope (TEM. The mechanical properties were determined from microhardness, shear strength, and compressive strength. Results showed that during the high-temperature sintering process, complex chemical reactions occurred, resulting in new phases of nucleation such as Ca3(PO42, TixPy, and Ti3O.The new phases, which easily dropped off under the action of external force, could hinder the densification of sintering and increase the brittleness of the nanocomposites. Results demonstrated that graphene had an impact on the microstructure and mechanical properties of the nanocomposites. Based on the mechanical properties and microstructure of the nanocomposites, the strengthening and fracture mechanisms of the graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were analyzed.

Trends in nanoscale mechanics mechanics of carbon nanotubes, graphene, nanocomposites and molecular dynamics

CERN Document Server

2014-01-01

This book contains a collection of the state-of-the-art reviews written by the leading researchers in the areas of nanoscale mechanics, molecular dynamics, nanoscale modeling of nanocomposites and mechanics of carbon nanotubes. No other book has reviews of the recent discoveries such as a nanoscale analog of the Pauli’s principle, i.e., effect of the spatial exclusion of electrons or the SEE effect, a new Registry Matrix Analysis for the nanoscale interfacial sliding and new data on the effective viscosity of interfacial electrons in nanoscale stiction at the interfaces. This volume is also an exceptional resource on the well tested nanoscale modeling of carbon nanotubes and nanocomposites, new nanoscale effects, unique evaluations of the effective thickness of carbon nanotubes under different loads, new data on which size of carbon nanotubes is safer and many other topics. Extensive bibliography concerning all these topics is included along with the lucid short reviews. Numerous illustrations are provided...

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

Electronic Resource Management Systems

Directory of Open Access Journals (Sweden)

Mark Ellingsen

2004-10-01

Full Text Available Computer applications which deal with electronic resource management (ERM are quite a recent development. They have grown out of the need to manage the burgeoning number of electronic resources particularly electronic journals. Typically, in the early years of e-journal acquisition, library staff provided an easy means of accessing these journals by providing an alphabetical list on a web page. Some went as far as categorising the e-journals by subject and then grouping the journals either on a single web page or by using multiple pages. It didn't take long before it was recognised that it would be more efficient to dynamically generate the pages from a database rather than to continually edit the pages manually. Of course, once the descriptive metadata for an electronic journal was held within a database the next logical step was to provide administrative forms whereby that metadata could be manipulated. This in turn led to demands for incorporating more information and more functionality into the developing application.

Development of nanocomposite polymer materials for electrical and electronic applications

International Nuclear Information System (INIS)

Chine, Bruno

2007-01-01

Some results and experimental procedures of laboratory are reported in the frame of researches conducted for the development of new nanostructured composite materials. These new materials, which are constituted by an organic phase: the polymer and an inorganic phase: the silicate, are being strongly investigated nowadays so it is expected that they could provide, among other, better electrical insulation properties and flame-delay in electrical and electronic applications. The laboratory experimental work has been developed from two families of polymers, thermoplastics and thermosets and clays silicates providing lamellar type. There are now some preliminary results, such as obtaining thin films of these nanocomposite materials, their complete characterization by X-ray diffraction, scanning microscopy and thermogravimetric analysis, they do well to wait for future research activities. (author) [es

Preparation and characterization of electronically conducting polypyrrole-montmorillonite nanocomposite and its potential application as a cathode material for oxygen reduction

International Nuclear Information System (INIS)

Rajapakse, R.M.G.; Murakami, Kenji; Bandara, H.M.N.; Rajapakse, R.M.M.Y.; Velauthamurti, K.; Wijeratne, S.

2010-01-01

Simple wet chemical processes were deployed to prepare low-cost conducting nanocomposites based on natural clays with 2:1 layered structures such as sodium montmorillonite (MMT). Ce(IV) modified MMT was used for the spontaneous polymerization of pyrrole within clay interlayers. The resulted clay-conducting polypyrrole nanocomposites containing the reduced form of the oxidising agent, have been extensively characterized by X-ray diffraction (XRD) technique for interlayer spacing variations and by Fourier transform infra red (FT-IR) spectroscopy to study the interactions between the clay and polymer functional groups. DC polarization technique with both blocking and non-blocking electrodes was used to distinguish between the ionic and electronic transport numbers and to recognize the type of mobile ionic species. AC impedance analysis further resolved the electrical conduction of these materials. Bulk conductivity analysis implied that the polypyrrole (PPY) formed within Ce(IV) modified MMT posses dominant electronic conductivity. The low-cost, light-weight and stable polymer-clay nanocomposite prepared by Ce(IV) intercalated MMT, [Ce(III)-PPY-MMT], seems to be a promising cathode material for oxygen reduction and hence may find applications in fuel cell industries.

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.

Dynamic shock compaction of a ZrO2-RuO2 electronic nanocomposite: toward functionally graded materials

NARCIS (Netherlands)

van Zyl, W.E.; Carton, Erik P.; Raming, T.P.; ten Elshof, Johan E.; Verweij, H.

2005-01-01

An electronic ZrO2-RuO2 nanocomposite was fabricated by dynamic compaction (DC) at 1.5 GPa resulting in a maximum relative density of 88% in the material. The DC process formed pristine elongated conical-shaped compacts 3 cm in length. The compacts retained their original nanometer-sized grains (~20

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 ...

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.

Electronic Resources Management Project Presentation 2012

KAUST Repository

Ramli, Rindra M.

2012-11-05

This presentation describes the electronic resources management project undertaken by the KAUST library. The objectives of this project is to migrate information from MS Sharepoint to Millennium ERM module. One of the advantages of this migration is to consolidate all electronic resources into a single and centralized location. This would allow for better information sharing among library staff.

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.

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.

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

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.

Organic/inorganic electrochromic nanocomposites with various interfacial interactions: A review

Energy Technology Data Exchange (ETDEWEB)

Xiong, Shanxin, E-mail: xiongsx@xust.edu.cn; Yin, Siyuan; Wang, Yuyun; Kong, Zhenzhen; Lan, Jinpeng; Zhang, Runlan; Gong, Ming; Wu, Bohua; Chu, Jia; Wang, Xiaoqin

2017-07-15

Highlights: • We review the effects of interfacial interactions in electrochromic nanocomposites. • Interfacial interactions are useful for film fabrication and property-enhancement. • The strong interaction can enhance the electron conduction and structural strength. • The weak interactions exist widely between organic and inorganic phases. • Multiple weak interactions can provide various performance-adjusting approaches. - Abstract: Electrochromic properties of organic or inorganic materials can be improved through preparing organic/inorganic electrochromic nanocomposites. In electrochromic nanocomposites, the interfacial interactions between the organic and inorganic phases play three important roles in preparation and application of the nanocomposites. Firstly, the interfacial interactions result in stable molecular structures. Secondly, they also improve the electron conduction and ion transport process in the nanocomposites. Thirdly, they enhance the electrochemical and electrochromic properties of the nanocomposites. In this paper, we review the common interfacial interactions including covalent bond, coordination bond, electrostatic interaction, hydrogen bond and π-π stacking interaction between the organic and inorganic phases in the electrochromic nanocomposites. The preparation method, the relationship between the structure and properties, and the mechanism of modulation of electrochromic effect in the nanocomposites with various interfacial interactions are surveyed. The strong interfacial interaction, e.g., covalent bond, is helpful for obtaining electrochromic nanocomposites with high electron conduction and high structural strength. However it is very complicated to construct covalent bond between the organic and inorganic phases. Another strong interfacial interaction, the coordination bond is mainly confined to preparation of electrochromic complex of metal ion and pyridine derivative. While, the weak interfacial interactions, e

Organic/inorganic electrochromic nanocomposites with various interfacial interactions: A review

International Nuclear Information System (INIS)

Xiong, Shanxin; Yin, Siyuan; Wang, Yuyun; Kong, Zhenzhen; Lan, Jinpeng; Zhang, Runlan; Gong, Ming; Wu, Bohua; Chu, Jia; Wang, Xiaoqin

2017-01-01

Highlights: • We review the effects of interfacial interactions in electrochromic nanocomposites. • Interfacial interactions are useful for film fabrication and property-enhancement. • The strong interaction can enhance the electron conduction and structural strength. • The weak interactions exist widely between organic and inorganic phases. • Multiple weak interactions can provide various performance-adjusting approaches. - Abstract: Electrochromic properties of organic or inorganic materials can be improved through preparing organic/inorganic electrochromic nanocomposites. In electrochromic nanocomposites, the interfacial interactions between the organic and inorganic phases play three important roles in preparation and application of the nanocomposites. Firstly, the interfacial interactions result in stable molecular structures. Secondly, they also improve the electron conduction and ion transport process in the nanocomposites. Thirdly, they enhance the electrochemical and electrochromic properties of the nanocomposites. In this paper, we review the common interfacial interactions including covalent bond, coordination bond, electrostatic interaction, hydrogen bond and π-π stacking interaction between the organic and inorganic phases in the electrochromic nanocomposites. The preparation method, the relationship between the structure and properties, and the mechanism of modulation of electrochromic effect in the nanocomposites with various interfacial interactions are surveyed. The strong interfacial interaction, e.g., covalent bond, is helpful for obtaining electrochromic nanocomposites with high electron conduction and high structural strength. However it is very complicated to construct covalent bond between the organic and inorganic phases. Another strong interfacial interaction, the coordination bond is mainly confined to preparation of electrochromic complex of metal ion and pyridine derivative. While, the weak interfacial interactions, e

PRINCIPLES OF CONTENT FORMATION EDUCATIONAL ELECTRONIC RESOURCE

Directory of Open Access Journals (Sweden)

О Ю Заславская

2017-12-01

Full Text Available The article considers modern possibilities of information and communication technologies for the design of electronic educational resources. The conceptual basis of the open educational multimedia system is based on the modular architecture of the electronic educational resource. The content of the electronic training module can be implemented in several versions of the modules: obtaining information, practical exercises, control. The regularities in the teaching process in modern pedagogical theory are considered: general and specific, and the principles for the formation of the content of instruction at different levels are defined, based on the formulated regularities. On the basis of the analysis, the principles of the formation of the electronic educational resource are determined, taking into account the general and didactic patterns of teaching.As principles of the formation of educational material for obtaining information for the electronic educational resource, the article considers: the principle of methodological orientation, the principle of general scientific orientation, the principle of systemic nature, the principle of fundamentalization, the principle of accounting intersubject communications, the principle of minimization. The principles of the formation of the electronic training module of practical studies in the article include: the principle of systematic and dose based consistency, the principle of rational use of study time, the principle of accessibility. The principles of the formation of the module for monitoring the electronic educational resource can be: the principle of the operationalization of goals, the principle of unified identification diagnosis.

Biocompatible epoxy modified bio-based polyurethane nanocomposites: mechanical property, cytotoxicity and biodegradation.

Science.gov (United States)

Dutta, Suvangshu; Karak, Niranjan; Saikia, Jyoti Prasad; Konwar, Bolin Kumar

2009-12-01

Epoxy modified Mesua ferrea L. seed oil (MFLSO) based polyurethane nanocomposites with different weight % of clay loadings (1%, 2.5% and 5%) have been evaluated as biocompatible materials. The nanocomposites were prepared by ex situ solution technique under high mechanical shearing and ultrasonication at room temperature. The partially exfoliated nanocomposites were characterized by Fourier transform infra-red (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The mechanical properties such as tensile strength and scratch hardness were improved 2 and 5 times, respectively by nanocomposites formation. Even the impact resistance improved a little. The thermostability of the nanocomposites was enhanced by about 40 degrees C. Biodegradation study confirmed 5-10 fold increase in biodegradation rate for the nanocomposites compared to the pristine polymers. All the nanocomposites showed non-cytotoxicity as evident from RBC hemolysis inhibition observed in anti-hemolytic assay carried over the sterilized films. The study reveals that the epoxy modified MFLSO based polyurethane nanocomposites deserve the potential to be applicable as biomaterials.

Implementing CORAL: An Electronic Resource Management System

Science.gov (United States)

Whitfield, Sharon

2011-01-01

A 2010 electronic resource management survey conducted by Maria Collins of North Carolina State University and Jill E. Grogg of University of Alabama Libraries found that the top six electronic resources management priorities included workflow management, communications management, license management, statistics management, administrative…

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...

Synthesis and characterization of intercalated polyaniline-clay nanocomposite using supercritical CO2

Science.gov (United States)

Abdelraheem, A.; El-Shazly, A. H.; Elkady, M. F.

2018-05-01

Lately, supercritical CO2 (SCCO2) have been getting great interest. It can be used in numerous applications because it is environmentally friendly, safe, comparatively low cost, and nonflammable. One of its applications is being a solvent in the synthesis of polymeric-clay nanocomposite. In this paper, intercalated polyaniline-clay nanocomposite (PANC) was prepared using SCCO2. The intercalation structure of polyaniline chains between clay layers was verified by various characterization techniques. Scanning electron microscope and transmission electron microscope (SEM-TEM) were used to show the morphology of the synthesized nanocomposite. The molecular structure of PANC nanocomposite was confirmed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The BET surface area and the conductivity of the nanocomposite were determined.

Preparation of flexible PLA/PEG-POSS nanocomposites by melt blending and radiation crosslinking

International Nuclear Information System (INIS)

Jung, Chang-Hee; Hwang, In-Tae; Jung, Chan-Hee; Choi, Jae-Hak

2014-01-01

In this study, poly(lactic acid) (PLA)/poly(ethylene glycol)-functionalized polyhedral oligomeric silsesquioxane (PEG-POSS) nanocomposites with or without triallyl isocyanurate (TAIC) were investigated by melt blending and electron beam irradiation to enhance the flexibility of PLA. Based on the results of the crosslinking degree measurements, the PLA/PEG-POSS nanocomposites were crosslinked by electron beam irradiation in the presence of triallyl isocyanurate (TAIC) and their crosslinking degree reached up to 80% based on the absorbed dose and their compositions. From the results of the FE-SEM and EDX Si-mapping, the crosslinked PLA/PEG-POSS nanocomposites were homogenous without a micro-phase separation or radiation-induced morphological change. Based on the results of the tensile test, the PLA/PEG-POSS nanocomposites containing 15 wt% PEG-POSS exhibited the highest flexibility, and their tensile strength showed a maximum value of 44.5 MPa after electron beam irradiation at an absorbed dose of 100 kGy in the presence of TAIC, which is comparable to non-biodegradable polypropylene. The results of the dynamic mechanical analysis revealed that the crosslinked PLA/PEG-POSS nanocomposites exhibited a higher thermal resistance above their melting temperature in comparison to that of the neat PLA, although their glass transition temperature was lower than that of the neat PLA. The enzymatic biodegradation test revealed that the PLA/PEG-POSS nanocomposites were biodegradable even though their biodegradability was deteriorated in comparison to that of the neat PLA. - Highlights: • PLA/PEG-POSS nanocomposites were prepared by melt blending. • The nanocomposites containing TAIC were crosslinked by electron beam irradiation. • The mechanical properties of the nanocomposites were comparable to polypropylene. • The crosslinked nanocomposites can be biodegradable

Managing electronic resources a LITA guide

CERN Document Server

Weir, Ryan O

2012-01-01

Informative, useful, current, Managing Electronic Resources: A LITA Guide shows how to successfully manage time, resources, and relationships with vendors and staff to ensure personal, professional, and institutional success.

Improved mechanical and functional properties of elastomer/graphite nanocomposites prepared by latex compounding

Energy Technology Data Exchange (ETDEWEB)

Yang Jian [Key Laboratory for Nano-materials, Beijing University of Chemical Technology, Ministry of Education of China, Beijing 100029 (China); Key Laboratory on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Tian Ming [Key Laboratory for Nano-materials, Beijing University of Chemical Technology, Ministry of Education of China, Beijing 100029 (China); Jia Qingxiu [Key Laboratory on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Shi Junhong [Key Laboratory for Nano-materials, Beijing University of Chemical Technology, Ministry of Education of China, Beijing 100029 (China); Zhang Liqun [Key Laboratory for Nano-materials, Beijing University of Chemical Technology, Ministry of Education of China, Beijing 100029 (China); Key Laboratory on Preparation and Processing of Novel Polymer Materials, Beijing University of Chemical Technology, Beijing 100029 (China)], E-mail: zhanglq@mail.buct.edu.cn; Lim Szuhui; Yu Zhongzhen [Centre for Advanced Materials Technology (CAMT), School of Aerospace, Mechanical and Mechatronic Engineering (J07), University of Sydney, Sydney, NSW 2006 (Australia); Mai Yiuwing [Centre for Advanced Materials Technology (CAMT), School of Aerospace, Mechanical and Mechatronic Engineering (J07), University of Sydney, Sydney, NSW 2006 (Australia)], E-mail: y.mai@usyd.edu.au

2007-10-15

The facile latex approach has been adopted to finely incorporate graphite nanosheets into elastomeric polymer matrix to obtain high-performance elastomeric nanocomposites with improved mechanical properties and functional properties. Scanning electron microscopy, transmission electron microscopy and X-ray diffraction experiments show that the nanostructures of the final nanocomposites exhibit a high degree of exfoliation and intercalation of graphite in the nitrile-butadiene rubber (NBR) matrix. Mechanical and dynamic-mechanical tests demonstrate that the NBR/graphite nanocomposites possess greatly increased elastic modulus and tensile strength, and desirably strong interfaces. The unexpected self-crosslinking of elastomer/graphite nanocomposites was discovered and then verified by oscillating disc rheometry and equilibrium swelling experiments. After critically examining various polymer types by X-ray photoelectron spectroscopy, electron spin resonance and Fourier transform infrared spectroscopy, a radical initiation mechanism was proposed to explain the self-crosslinking reaction. These NBR/graphite nanocomposites possess significantly improved wear resistance and gas barrier properties, and superior electrical/thermal conductivity. Such versatile functional properties make NBR nanocomposites a promising new class of advanced materials.

Improved mechanical and functional properties of elastomer/graphite nanocomposites prepared by latex compounding

International Nuclear Information System (INIS)

Yang Jian; Tian Ming; Jia Qingxiu; Shi Junhong; Zhang Liqun; Lim Szuhui; Yu Zhongzhen; Mai Yiuwing

2007-01-01

The facile latex approach has been adopted to finely incorporate graphite nanosheets into elastomeric polymer matrix to obtain high-performance elastomeric nanocomposites with improved mechanical properties and functional properties. Scanning electron microscopy, transmission electron microscopy and X-ray diffraction experiments show that the nanostructures of the final nanocomposites exhibit a high degree of exfoliation and intercalation of graphite in the nitrile-butadiene rubber (NBR) matrix. Mechanical and dynamic-mechanical tests demonstrate that the NBR/graphite nanocomposites possess greatly increased elastic modulus and tensile strength, and desirably strong interfaces. The unexpected self-crosslinking of elastomer/graphite nanocomposites was discovered and then verified by oscillating disc rheometry and equilibrium swelling experiments. After critically examining various polymer types by X-ray photoelectron spectroscopy, electron spin resonance and Fourier transform infrared spectroscopy, a radical initiation mechanism was proposed to explain the self-crosslinking reaction. These NBR/graphite nanocomposites possess significantly improved wear resistance and gas barrier properties, and superior electrical/thermal conductivity. Such versatile functional properties make NBR nanocomposites a promising new class of advanced materials

Flexible Transparent Supercapacitors Based on Hierarchical Nanocomposite Films.

Science.gov (United States)

Chen, Fanhong; Wan, Pengbo; Xu, Haijun; Sun, Xiaoming

2017-05-31

Flexible transparent electronic devices have recently gained immense popularity in smart wearable electronics and touch screen devices, which accelerates the development of the portable power sources with reliable flexibility, robust transparency and integration to couple these electronic devices. For potentially coupled as energy storage modules in various flexible, transparent and portable electronics, the flexible transparent supercapacitors are developed and assembled from hierarchical nanocomposite films of reduced graphene oxide (rGO) and aligned polyaniline (PANI) nanoarrays upon their synergistic advantages. The nanocomposite films are fabricated from in situ PANI nanoarrays preparation in a blended solution of aniline monomers and rGO onto the flexible, transparent, and stably conducting film (FTCF) substrate, which is obtained by coating silver nanowires (Ag NWs) layer with Meyer rod and then coating of rGO layer on polyethylene terephthalate (PET) substrate. Optimization of the transparency, the specific capacitance, and the flexibility resulted in the obtained all-solid state nanocomposite supercapacitors exhibiting enhanced capacitance performance, good cycling stability, excellent flexibility, and superior transparency. It provides promising application prospects for exploiting flexible, low-cost, transparent, and high-performance energy storage devices to be coupled into various flexible, transparent, and wearable electronic devices.

Stimuli-Responsive Polymer-Clay Nanocomposites under Electric Fields

Science.gov (United States)

Piao, Shang Hao; Kwon, Seung Hyuk; Choi, Hyoung Jin

2016-01-01

This short Feature Article reviews electric stimuli-responsive polymer/clay nanocomposites with respect to their fabrication, physical characteristics and electrorheological (ER) behaviors under applied electric fields when dispersed in oil. Their structural characteristics, morphological features and thermal degradation behavior were examined by X-ray diffraction pattern, scanning electron microscopy and transmission electron microscopy, and thermogravimetric analysis, respectively. Particular focus is given to the electro-responsive ER characteristics of the polymer/clay nanocomposites in terms of the yield stress and viscoelastic properties along with their applications. PMID:28787852

Chemically stabilized reduced graphene oxide/zirconia nanocomposite: synthesis and characterization

Science.gov (United States)

Sagadevan, Suresh; Zaman Chowdhury, Zaira; Enamul Hoque, Md; Podder, Jiban

2017-11-01

In this research, chemical method was used to fabricate reduced graphene oxide/zirconia (rGO/ZrO2) nanocomposite. X-ray Diffraction analysis (XRD) was carried out to examine the crystalline structure of the nanocomposites. The nanocomposite prepared here has average crystallite size of 14 nm. The surface morphology was observed using scanning electron microscopic analysis (SEM) coupled with electron dispersion spectroscopy (EDS) to detect the chemical element over the surface of the nanocomposites. High-resolution Transmission electron microscopic analysis (HR-TEM) was carried out to determine the particle size and shape of the nanocomposites. The optical property of the prepared samples was determined using UV-visible absorption spectrum. The functional groups were identified using FTIR and Raman spectroscopic analysis. Efficient, cost effective and properly optimized synthesis process of rGO/ZrO2 nanocomposite can ensure the presence of infiltrating graphene network inside the ZrO2 matrix to enhance the electrical properties of the hybrid composites up to a greater scale. Thus the dielectric constant, dielectric loss and AC conductivity of the prepared sample was measured at various frequencies and temperatures. The analytical results obtained here confirmed the homogeneous dispersion of ZrO2 nanostructures over the surface of reduced graphene oxide nanosheets. Overall, the research demonstrated that the rGO/ZrO2 nano-hybrid structure fabricated here can be considered as a promising candidate for applications in nanoelectronics and optoelectronics.

Thermal Stability and Magnetic Properties of Polyvinylidene Fluoride/Magnetite Nanocomposites

OpenAIRE

Ouyang, Zen-Wei; Chen, Erh-Chiang; Wu, Tzong-Ming

2015-01-01

This work describes the thermal stability and magnetic properties of polyvinylidene fluoride (PVDF)/magnetite nanocomposites fabricated using the solution mixing technique. The image of transmission electron microscopy for PVDF/magnetite nanocomposites reveals that the 13 nm magnetite nanoparticles are well distributed in PVDF matrix. The electroactive β-phase and piezoelectric responses of PVDF/magnetite nanocomposites are increased as the loading of magnetite nanoparticles increases. The pi...

Characterization and properties of sepiolite/polyurethane nanocomposites

International Nuclear Information System (INIS)

Chen Hongxiang; Zheng Maosheng; Sun Hongying; Jia Qingming

2007-01-01

In situ polymerization method is employed to prepare sepiolite/polyurethane nanocomposite. The morphology and the dispersion of sepiolite in polyurethane have been characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope and Fourier transform infrared spectroscopy. The results show the sepiolite is dispersed homogeneously in the polyurethane matrix at a nanometer scale. The tensile test shows that the tensile strength and elongation at break for the nanocomposites increase with the addition of sepiolite as compared to those of the pure polyurethane. The TGA analysis reveals that the addition of nanofillers results in the higher thermal stability

ZnO/Cu nanocomposite: a platform for direct electrochemistry of enzymes and biosensing applications.

Science.gov (United States)

Yang, Chi; Xu, Chunxiang; Wang, Xuemei

2012-03-06

Unique structured nanomaterials can facilitate the direct electron transfer between redox proteins and the electrodes. Here, in situ directed growth on an electrode of a ZnO/Cu nanocomposite was prepared by a simple corrosion approach, which enables robust mechanical adhesion and electrical contact between the nanostructured ZnO and the electrodes. This is great help to realize the direct electron transfer between the electrode surface and the redox protein. SEM images demonstrate that the morphology of the ZnO/Cu nanocomposite has a large specific surface area, which is favorable to immobilize the biomolecules and construct biosensors. Using glucose oxidase (GOx) as a model, this ZnO/Cu nanocomposite is employed for immobilization of GOx and the construction of the glucose biosensor. Direct electron transfer of GOx is achieved at ZnO/Cu nanocomposite with a high heterogeneous electron transfer rate constant of 0.67 ± 0.06 s(-1). Such ZnO/Cu nanocomposite provides a good matrix for direct electrochemistry of enzymes and mediator-free enzymatic biosensors.

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)

Graphene-Decorated Nanocomposites for Printable Electrodes in Thin Wafer Devices

Science.gov (United States)

Bakhshizadeh, N.; Sivoththaman, S.

2017-12-01

Printable electrodes that induce less stress and require lower curing temperatures compared to traditional screen-printed metal pastes are needed in thin wafer devices such as future solar cells, and in flexible electronics. The synthesis of nanocomposites by incorporating graphene nanopowders as well as silver nanowires into epoxy-based electrically conductive adhesives (ECA) is examined to improve electrical conductivity and to develop alternate printable electrode materials that induce less stress on the wafer. For the synthesized graphene and Ag nanowire-decorated ECA nanocomposites, the curing kinetics were studied by dynamic and isothermal differential scanning calorimetry measurements. Thermogravimetric analysis on ECA, ECA-AG and ECA/graphene nanopowder nanocomposites showed that the temperatures for onset of decomposition are higher than their corresponding glass transition temperature ( T g) indicating an excellent thermal resistance. Printed ECA/Ag nanowire nanocomposites showed 90% higher electrical conductivity than ECA films, whereas the ECA/graphene nanocomposites increased the conductivity by over two orders of magnitude. Scanning electron microscopy results also revealed the effect of fillers morphology on the conductivity improvement and current transfer mechanisms in nanocomposites. Residual stress analysis performed on Si wafers showed that the ECA and nanocomposite printed wafers are subjected to much lower stress compared to those printed with metallic pastes. The observed parameters of low curing temperature, good thermal resistance, reasonably high conductivity, and low residual stress in the ECA/graphene nanocomposite makes this material a promising alternative in screen-printed electrode formation in thin substrates.

Preparation of nanocomposite γ-Al2O3/polyethylene separator crosslinked by electron beam irradiation for lithium secondary battery

Science.gov (United States)

Nho, Young-Chang; Sohn, Joon-Yong; Shin, Junhwa; Park, Jong-Seok; Lim, Yoon-Mook; Kang, Phil-Hyun

2017-03-01

Although micro-porous membranes made of polyethylene (PE) offer excellent mechanical strength and chemical stability, they exhibit large thermal shrinkage at high temperature, which causes a short circuit between positive and negative electrodes in cases of unusual heat generation. We tried to develop a new technology to reduce the thermal shrinkage of PE separators by introducing γ-Al2O3 particles treated with coupling agent on PE separators. Nanocomposite γ-Al2O3/PE separators were prepared by the dip coating of polyethylene(PE) separators in γ-Al2O3/poly(vinylidenefluoride-hexafluoropropylene) (PVDF-HFP)/crosslinker (1,3,5-trially-1,3,5-triazine-2,4,6(1 H,3 H,5 H)-trione (TTT) solution with humidity control followed by electron beam irradiation. γ-Al2O3/PVDF-HFP/TTT (95/5/2)-coated PE separator showed the highest electrolyte uptake (157%) and ionic conductivity (1.3 mS/cm). On the basis of the thermal shrinkage test, the nanocomposite γ-Al2O3/PE separators containing TTT irradiated by electron beam exhibited a higher thermal resistance. Moreover, a linear sweep voltammetry test showed that the irradiated nanocomposite γ-Al2O3/PE separators have electrochemical stabilities of up to 5.0 V. In a battery performance test, the coin cell assembled with γ-Al2O3/PVDF-HFP/TTT-coated PE separator showed excellent discharge cycle performance.

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.

Polyetherimide/bucky gels nanocomposites with superior conductivity and thermal stability

KAUST Repository

Chen, Ye

2013-08-14

Polyetherimide (PEI) nanocomposites comprising bucky gels of industrial-grade multiwalled carbon nanotubes (MWCNTs) and ionic liquid (IL, 1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIM][PF6])) were prepared. The processing framework for this nanocomposite is simple, reproducible, and easily scalable. The strong interaction between IL and MWCNTs caused the latter to uniformly disperse in the PEI matrix while IL flowed into the gaps between the nanotubes\\' walls. The nanocomposite exhibited an enhanced conductivity of 2.01 × 104 Ω·cm volume resistivity at room temperature; the value decreased dramatically by 12 orders of magnitude, compared to pristine PEI. The IL free ions and MWCNTs networks provided excellent channels for electron transfer. PEI/bucky gels nanocomposites also showed improved thermal stability and high tensile strength. Other than having antiwear properties, this material can have numerous applications in the aerospace and electronics industries. Moreover, our work presents a "green" method toward modified nanocomposites industrial production as IL is environmentally safe and is easily recyclable. © 2013 American Chemical Society.

Polyetherimide/bucky gels nanocomposites with superior conductivity and thermal stability

KAUST Repository

Chen, Ye; Tao, Jing; Deng, Lin; LI, LIANG; Li., Jun; Yang, Yang; Khashab, Niveen M.

2013-01-01

Polyetherimide (PEI) nanocomposites comprising bucky gels of industrial-grade multiwalled carbon nanotubes (MWCNTs) and ionic liquid (IL, 1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIM][PF6])) were prepared. The processing framework for this nanocomposite is simple, reproducible, and easily scalable. The strong interaction between IL and MWCNTs caused the latter to uniformly disperse in the PEI matrix while IL flowed into the gaps between the nanotubes' walls. The nanocomposite exhibited an enhanced conductivity of 2.01 × 104 Ω·cm volume resistivity at room temperature; the value decreased dramatically by 12 orders of magnitude, compared to pristine PEI. The IL free ions and MWCNTs networks provided excellent channels for electron transfer. PEI/bucky gels nanocomposites also showed improved thermal stability and high tensile strength. Other than having antiwear properties, this material can have numerous applications in the aerospace and electronics industries. Moreover, our work presents a "green" method toward modified nanocomposites industrial production as IL is environmentally safe and is easily recyclable. © 2013 American Chemical Society.

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.

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

Improving the drug delivery characteristics of graphene oxide based polymer nanocomposites through the “one-pot” synthetic approach of single-electron-transfer living radical polymerization

Energy Technology Data Exchange (ETDEWEB)

Gao, Peng; Liu, Meiying; Tian, Jianwen; Deng, Fengjie [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Wang, Ke [Department of Chemistry and the Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing 100084 (China); Xu, Dazhuang [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Liu, Liangji [Affiliated Hospital of Jiangxi University of Traditional Chinese Medicine, Nanchang 330006 (China); Zhang, Xiaoyong, E-mail: xiaoyongzhang1980@gmail.com [Department of Chemistry, Nanchang University, 999 Xuefu Avenue, Nanchang 330031 (China); Wei, Yen, E-mail: weiyen@tsinghua.edu.cn [Department of Chemistry and the Tsinghua Center for Frontier Polymer Research, Tsinghua University, Beijing 100084 (China)

2016-08-15

Graphical abstract: The PEGylated graphene oxides with high water dispersibility, good biocompatibility as well as high drug loading capability were fabricated via “one-pot” SET-LRP. - Highlights: • Surface modification of graphene oxide with polymers. • One-pot single-electron-transfer living radical polymerization. • Improving drug delivery characteristics. • The synthetic approach is rather simple, universal and effective. - Abstract: Graphene oxide (GO) based polymer nanocomposites have attracted extensive research interest recently for their outstanding physicochemical properties and potential applications. However, surface modification of GO with synthetic polymers has demonstrated to be trouble for most polymerization procedures are occurred under non-aqueous solution, which will in turn lead to the restacking of GO. In this work, a facile and efficient “one-pot” strategy has been developed for surface modification of GO with synthetic polymers through single-electron-transfer living radical polymerization (SET-LRP). The GO based polymer nanocomposites were obtained via SET-LRP in aqueous solution using poly(ethylene glycol) methyl ether methacrylate (PEGMA) as the monomer and 11-bromoundecanoic acid as the initiator, which could be effectively adsorbed on GO through hydrophobic interaction. The successful preparation of GO based polymer nanocomposites was confirmed by a series of characterization techniques such as {sup 1}H nuclear magnetic resonance, Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy and X-ray photoelectron spectroscopy. The resultant products exhibit high water disperisibility, excellent biocompatibility and high efficient drug loading capability, making these PEGylated GO nanocomposites promising candidates for biomedical applications.

Single Step In Situ Synthesis and Optical Properties of Polyaniline/ZnO Nanocomposites

Directory of Open Access Journals (Sweden)

Deepali Sharma

2014-01-01

Full Text Available Polyaniline/ZnO nanocomposites were prepared by in situ oxidative polymerization of aniline monomer in the presence of different weight percentages of ZnO nanostructures. The steric stabilizer added to prevent the agglomeration of nanostructures in the polymer matrix was found to affect the final properties of the nanocomposite. ZnO nanostructures of various morphologies and sizes were prepared in the absence and presence of sodium lauryl sulphate (SLS surfactant under different reaction conditions like in the presence of microwave radiation (microwave oven, under pressure (autoclave, under vacuum (vacuum oven, and at room temperature (ambient condition. The conductivity of these synthesized nanocomposites was evaluated using two-probe method and the effect of concentration of ZnO nanostructures on conductivity was observed. X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FTIR, and UV-visible (UV-VIS spectroscopy techniques were used to characterize nanocomposites. The optical energy band gap of the nanocomposites was calculated from absorption spectra and ranged between 1.5 and 3.21 eV. The reported values depicted the blue shift in nanocomposites as compared to the band gap energies of synthesized ZnO nanostructures. The present work focuses on the one-step synthesis and potential use of PANI/ZnO nanocomposite in molecular electronics as well as in optical devices.

Morphological, viscoelastic and mechanical characterization of polypropylene/exfoliated graphite nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Creusa Iara; Oliveira, Ricardo Vinicius Bof de; Mauler, Raquel Santos, E-mail: raquel.mauler@ufrgs.br [Universidade Federal do Rio Grande do Sul (PGCIMAT/IQ/UFRGS), Porto Alegre, RS (Brazil); Bianchi, Otavio [Universidade de Caxias do Sul (PGMAT/CCET/UCS), RS (Brazil); Oviedo, Mauro Alfredo Soto [Braskem S/A, Rio de Janeiro, RJ (Brazil)

2013-07-01

The viscoelastic, mechanical and morphological properties of polypropylene/exfoliated graphite nanocomposites with different contents of nanofiller were investigated. According to transmission electron microscopy results, the nanofiller particles were homogeneously dispersed in the matrix. The rheological properties indicated that incorporation of graphite improved the matrix stiffness and had a reinforcing effect. Exfoliated graphite had a weak interaction with the polypropylene. The behavior of the nanocomposites was similar to that of polypropylene in terms of the interfacial detachment inferred from the transmission electron microscopy images and of their G' (storage) and G' (loss) moduli, and viscosity. The mechanical properties of the nanocomposites compared to the matrix improved significantly for the flexural and storage moduli with little loss of impact strength. (author)

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

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.

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.

A simple biogenic route to rapid synthesis of Au-TiO{sub 2} nanocomposites by electrochemically active biofilms

Energy Technology Data Exchange (ETDEWEB)

Kalathil, Shafeer; Khan, Mohammad Mansoob [Yeungnam University, School of Chemical Engineering (Korea, Republic of); Banerjee, Arghya Narayan [Yeungnam University, School of Mechanical Engineering (Korea, Republic of); Lee, Jintae; Cho, Moo Hwan, E-mail: mhcho@ynu.ac.kr [Yeungnam University, School of Chemical Engineering (Korea, Republic of)

2012-08-15

Deposition of gold on titanium dioxide (TiO{sub 2}) nanoparticles is highly beneficial for maximizing the efficiency of many photocatalytic reactions. In this study, we have reported for the first time the use of an electrochemically active biofilm (EAB) for the synthesis of Au-TiO{sub 2} nanocomposite with sodium acetate as the electron donor. The EAB acts as an electron generator for the reduction of gold ions on the surface of TiO{sub 2} nanoparticles. It was observed that the TiO{sub 2} plays not only as a support for the gold nanoparticles but also as a storage of electrons produced by the EAB within the particles. These stored electrons dramatically increase the reduction of gold ions and hence we have observed the formation of the Au-TiO{sub 2} nanocomposites within 90 min. A mechanism of the nanocomposite formation is also proposed. The as-synthesized nanocomposites were characterized by UV-Vis absorption spectroscopy to monitor the proper formation of the nanocomposites. X-ray diffraction and transmission electron microscopic analyses were performed to determine the structural and microstructural properties of the nanocomposites. High-resolution transmission electron micrographs depict the proper formation of the Au-TiO{sub 2} nanocomposites with gold nanoparticle size varying from 5 to 10 nm with an increase in the gold precursor concentration. Zeta potential measurements were used to investigate surface charges of the as-synthesized nanocomposites. This novel biogenic route represents a unique pathway for the low cost, eco-friendly, rapid, and controlled synthesis of nanostructured Au-TiO{sub 2} hybrid systems which will truly revolutionize the synthetic fields of nanocomposites.

Reduced graphene oxide-germanium quantum dot nanocomposite: electronic, optical and magnetic properties

Science.gov (United States)

Amollo, Tabitha A.; Mola, Genene T.; Nyamori, Vincent O.

2017-12-01

Graphene provides numerous possibilities for structural modification and functionalization of its carbon backbone. Localized magnetic moments can, as well, be induced in graphene by the formation of structural defects which include vacancies, edges, and adatoms. In this work, graphene was functionalized using germanium atoms, we report the effect of the Ge ad atoms on the structural, electrical, optical and magnetic properties of graphene. Reduced graphene oxide (rGO)-germanium quantum dot nanocomposites of high crystalline quality were synthesized by the microwave-assisted solvothermal reaction. Highly crystalline spherical shaped germanium quantum dots, of diameter ranging between 1.6-9.0 nm, are anchored on the basal planes of rGO. The nanocomposites exhibit high electrical conductivity with a sheet resistance of up to 16 Ω sq-1. The electrical conductivity is observed to increase with the increase in Ge content in the nanocomposites. High defect-induced magnetization is attained in the composites via germanium adatoms. The evolution of the magnetic moments in the nanocomposites and the coercivity showed marked dependence on the Ge quantum dots size and concentration. Quantum confinement effects is evidenced in the UV-vis absorbance spectra and photoluminescence emission spectra of the nanocomposites which show marked size-dependence. The composites manifest strong absorption in the UV region, strong luminescence in the near UV region, and a moderate luminescence in the visible region.

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.

Gender Analysis Of Electronic Information Resource Use: The Case ...

African Journals Online (AJOL)

Based on the findings the study concluded that access and use of electronic information resources creates a “social digital divide” along gender lines. The study ... Finally, the library needs to change its marketing strategies on the availability of electronic information resources to increase awareness of these resources.

Enhanced performance of inverted organic photovoltaic cells using CNTs-TiO(X) nanocomposites as electron injection layer.

Science.gov (United States)

Zhang, Hong; Xu, Meifeng; Cui, Rongli; Guo, Xihong; Yang, Shangyuan; Liao, Liangsheng; Jia, Quanjie; Chen, Yu; Dong, Jinquan; Sun, Baoyun

2013-09-06

In this study, we fabricated inverted organic photovoltaic cells with the structure ITO/carbon nanotubes (CNTs)-TiO(X)/P3HT:PCBM/MoO₃/Al by spin casting CNTs-TiO(X) nanocomposite (CNTs-TiO(X)) as the electron injection layer onto ITO/glass substrates. The power conversion efficiency (PCE) of the 0.1 wt% single-walled nanotubes (SWNTs)-TiO(X) nanocomposite device was almost doubled compared with the TiO(X) device, but with increasing concentration of the incorporated SWNTs in the TiO(X) film, the performance of the devices appeared to decrease rapidly. Devices with multi-walled NTs in the TiO(X) film have a similar trend. This phenomenon mainly depends on the inherent physical and chemical characteristics of CNTs such as their high surface area, their electron-accepting properties and their excellent carrier mobility. However, with increasing concentration of CNTs, CNTs-TiO(X) current leakage pathways emerged and also a recombination of charges at the interfaces. In addition, there was a significant discovery. The incorporated CNTs were highly conducive to enhancing the degree of crystallinity and the ordered arrangement of the P3HT in the active layers, due to the intermolecular π-π stacking interactions between CNTs and P3HT.

Users satisfaction with electronic information resources and services ...

African Journals Online (AJOL)

This study investigated users satisfaction on the use of electronic information resources and services in MTN Net libraries in ABU & UNIBEN. Two objectives and one null hypotheses were formulated and tested with respect to the users' satisfaction on electronic information resources and services in MTN Net libraries in ...

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

Electrochemical reactivity of Co-Li2S nanocomposite for lithium-ion batteries

International Nuclear Information System (INIS)

Zhou, Yongning; Wu, Changliang; Zhang, Hua; Wu, Xiaojing; Fu, Zhengwen

2007-01-01

The fabrication of Co-Li 2 S nanocomposite thin film is reported by pulsed laser deposition (PLD) for the first time. Li 2 S-Co nanocomposite thin film is used as storing Li electrodes that have led to promising electrochemical activity and good electrochemical performance. The releasing Li process from the as-deposited Li 2 S-Co nanocomposite thin films is confirmed by the ex situ high resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED) measurements and may come from the decomposition of Li 2 S with and without the interaction of metal Co into CoS 2 and S. The electrochemical reaction mechanism of Co-Li 2 S nanocomposite film electrode involving both the formation and decomposition of Li 2 S and the lithium extraction/insertion of CoS 2 after the initial charging process is proposed. Our results demonstrate the advantages of using Co-Li 2 S nanocomposite in storage lithium materials

Synthesis and characterization of polyaniline coated gold nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Zuber, Siti Nurzulaiha Mohd; Kamarun, Dzaraini; Zaki, Hamizah; Kamarudin, Mohamad Shukri [Faculty of Applied Sciences, Universiti Teknologi MARA (UiTM), Shah Alam, 40450 Selangor Darul Ehsan (Malaysia); Thomas, Sabu; Kalarikkal, Nandakumar [International and Inter University Centre of Nanoscience and Nanotechnoogy, Mahatma Ghandi University, Priyadarsini Hills Kottayam, Kerala India-686560 (India)

2015-08-28

Considerable attention has been drawn during the last two decades to prepare nanocomposites consists of conducting polymer and noble metal due to their potential ability to generate a new class of material with novel optical, chemical, electronic or mechanical properties for various applications. In this work, an attempt has been made to synthesize nanocomposite of polyaniline (PANI) coated with gold nanoparticles (AuNPs) chemically with various types of surfactants such as polyvinylpyrrolidone (PVP), and sodium dodecyl sulphate (SDS) which act as stabilizing agents to help in stabilization of the PANI/Gold nanocomposites system. The synthesized nanocomposites were characterized by UV-Visible, field emission scanning electron microscope (FESEM) and particle size analyzer (PSA). The formation of finger like structure can be seen in the FESEM images when the AuNPs were incorporated into the polymer matrix. The EDX data showed that 18.66% and 12.67% of AuNPs atoms were present in the composite system thus proved the incorporation of AuNPs into the polymer matrix. A small red shift of the absorption peak in the UV-Vis of both PANI/AuNPs composites system may be due to the incorporation of AuNPs in the PANI matrix.

Synthesis and characterization of polyaniline coated gold nanocomposites

International Nuclear Information System (INIS)

Zuber, Siti Nurzulaiha Mohd; Kamarun, Dzaraini; Zaki, Hamizah; Kamarudin, Mohamad Shukri; Thomas, Sabu; Kalarikkal, Nandakumar

2015-01-01

Considerable attention has been drawn during the last two decades to prepare nanocomposites consists of conducting polymer and noble metal due to their potential ability to generate a new class of material with novel optical, chemical, electronic or mechanical properties for various applications. In this work, an attempt has been made to synthesize nanocomposite of polyaniline (PANI) coated with gold nanoparticles (AuNPs) chemically with various types of surfactants such as polyvinylpyrrolidone (PVP), and sodium dodecyl sulphate (SDS) which act as stabilizing agents to help in stabilization of the PANI/Gold nanocomposites system. The synthesized nanocomposites were characterized by UV-Visible, field emission scanning electron microscope (FESEM) and particle size analyzer (PSA). The formation of finger like structure can be seen in the FESEM images when the AuNPs were incorporated into the polymer matrix. The EDX data showed that 18.66% and 12.67% of AuNPs atoms were present in the composite system thus proved the incorporation of AuNPs into the polymer matrix. A small red shift of the absorption peak in the UV-Vis of both PANI/AuNPs composites system may be due to the incorporation of AuNPs in the PANI matrix

Green fabrication of quaternized chitosan/rectorite/Ag NP nanocomposites with antimicrobial activity

International Nuclear Information System (INIS)

Luo, Jiwen; Xie, Meijia; Wang, Xiaoying

2014-01-01

Silver nanoparticles (Ag NPs) were synthesized rapidly in one pot via the Tollens reaction, in which quaternized chitosan (QCS) and rectorite (REC) acted as the reducing and stabilizing agent, while other chemical reducing and stabilizing agents and the surfactant were not included. X-ray diffraction, scanning electron microscopy and transmission electron microscopy results showed that spherical Ag NPs with uniform sizes were obtained, the layers of clay were peeled and thus exfoliated QCS/REC/Ag NP (QCRAg) nanocomposite was achieved. Moreover, Ag NPs dispersed well in the exfoliated nanocomposite matrix, some Ag NPs even entered into the interlayer of REC. QCRAg nanocomposites showed strong antimicrobial activity; the lowest minimum inhibitory concentration against Staphyloccocus aureus was only 0.0001% (w/v). The study reveals that the obtained QCRAg nanocomposites have great potential for biomedical applications. (communication)

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.

Metallic Nanocomposites as Next-Generation Thermal Interface Materials

Energy Technology Data Exchange (ETDEWEB)

Feng, Xuhui [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Narumanchi, Sreekant V [National Renewable Energy Laboratory (NREL), Golden, CO (United States); King, Charles C [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Nagabandi, Nirup [Texas A& M University; Oh, Jun Kyun [Texas A& M University; Akbulut, Mustafa [Texas A& M University; Yegin, Cengiz [Texas A& M University

2017-07-27

Thermal interface materials (TIMs) are an integral and important part of thermal management in electronic devices. The electronic devices are becoming more compact and powerful. This increase in power processed or passing through the devices leads to higher heat fluxes and makes it a challenge to maintain temperatures at the optimal level during operation. Herein, we report a free standing nanocomposite TIM in which boron nitride nanosheets (BNNS) are uniformly dispersed in copper matrices via an organic linker, thiosemicarbazide. Integration of these metal-organic-inorganic nanocomposites was made possible by a novel electrodeposition technique where the functionalized BNNS (f-BNNS) experience the Brownian motion and reach the cathode through diffusion, while the nucleation and growth of the copper on the cathode occurs via the electrochemical reduction. Once the f-BNNS bearing carbonothioyl/thiol groups on the terminal edges come into the contact with copper crystals, the chemisorption reaction takes place. We performed thermal, mechanical, and structural characterization of these nanocomposites using scanning electron microcopy (SEM), diffusive laser flash (DLF) analysis, phase-sensitive transient thermoreflectence (PSTTR), and nanoindentation. The nanocomposites exhibited a thermal conductivity ranging from 211 W/mK to 277 W/mK at a filler mass loading of 0-12 wt.percent. The nanocomposites also have about 4 times lower hardness as compared to copper, with values ranging from 0.27 GPa to 0.41 GPa. The structural characterization studies showed that most of the BNNS are localized at grain boundaries - which enable efficient thermal transport while making the material soft. PSTTR measurements revealed that the synergistic combinations of these properties yielded contact resistances on the order of 0.10 to 0.13 mm2K/W, and the total thermal resistance of 0.38 to 0.56 mm2K/W at bondline thicknesses of 30-50 um. The coefficient of thermal expansion (CTE) of the

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

Morphological, viscoelastic and mechanical characterization of polypropylene/exfoliated graphite nanocomposites

Directory of Open Access Journals (Sweden)

Creusa Iara Ferreira

2013-01-01

Full Text Available The viscoelastic, mechanical and morphological properties of polypropylene/exfoliated graphite nanocomposites with different contents of nanofiller were investigated. According to transmission electron microscopy results, the nanofiller particles were homogeneously dispersed in the matrix. The rheological properties indicated that incorporation of graphite improved the matrix stiffness and had a reinforcing effect. Exfoliated graphite had a weak interaction with the polypropylene. The behavior of the nanocomposites was similar to that of polypropylene in terms of the interfacial detachment inferred from the transmission electron microscopy images and of their G' (storage and G'' (loss moduli, and viscosity. The mechanical properties of the nanocomposites compared to the matrix improved significantly for the flexural and storage moduli with little loss of impact strength.

Morphological, viscoelastic and mechanical characterization of polypropylene/exfoliated graphite nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Creusa Iara; Oliveira, Ricardo Vinicius Bof de; Mauler, Raquel Santos, E-mail: raquel.mauler@ufrgs.br [Universidade Federal do Rio Grande do Sul (PGCIMAT/IQ/UFRGS), Porto Alegre, RS (Brazil); Bianchi, Otavio [Universidade de Caxias do Sul (PGMAT/CCET/UCS), RS (Brazil); Oviedo, Mauro Alfredo Soto [Braskem S/A, Rio de Janeiro, RJ (Brazil)

2013-07-01

The viscoelastic, mechanical and morphological properties of polypropylene/exfoliated graphite nanocomposites with different contents of nanofiller were investigated. According to transmission electron microscopy results, the nanofiller particles were homogeneously dispersed in the matrix. The rheological properties indicated that incorporation of graphite improved the matrix stiffness and had a reinforcing effect. Exfoliated graphite had a weak interaction with the polypropylene. The behavior of the nanocomposites was similar to that of polypropylene in terms of the interfacial detachment inferred from the transmission electron microscopy images and of their G' (storage) and G' (loss) moduli, and viscosity. The mechanical properties of the nanocomposites compared to the matrix improved significantly for the flexural and storage moduli with little loss of impact strength. (author)

Fabrication, characterization and gas sensing studies of PPy/MWCNT/SLS nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Tiwari, D. C., E-mail: dctiwari2001@yahoo.com; Atri, Priyanka, E-mail: dctiwari2001@yahoo.com [SOS Electronics, Jiwaji University, Gwalior (M.P.)-474011 (India); Sharma, R. [CSIR-CEERI, Pilani (Rajasthan)-333031 (India)

2014-04-24

Multiwall carbon nanotubes (MWCNT) coated with polypyrrole nanocomposite was prepared by in-situ chemical oxidative polymerization method in the presence of surfactant (SLS). The scanning electron microscope (SEM) pictures indicate the core shell structure of PPy/MWCNT/SLS nanocomposite. Nature of the prepared material was investigated by X-ray diffraction spectroscopy. This nanocomposite shows the excellent gas sensing behaviour for ammonia gas at 150 ppm and 300 ppm levels.

Evaluation of poly (vinyl alcohol) based cryogel–zinc oxide nanocomposites for possible applications as wound dressing materials

Energy Technology Data Exchange (ETDEWEB)

Chaturvedi, Archana [Bose Memorial Research Laboratory, Department of Chemistry, Government Autonomous Science College Jabalpur (India); Bajpai, Anil K., E-mail: akbmrl@yahoo.co.in [Bose Memorial Research Laboratory, Department of Chemistry, Government Autonomous Science College Jabalpur (India); Bajpai, Jaya [Bose Memorial Research Laboratory, Department of Chemistry, Government Autonomous Science College Jabalpur (India); Singh, Sunil K. [Department of Chemistry, Guru Ghasidas University, Bilaspur, CG (India)

2016-08-01

In this investigation cryogels composed of poly (vinyl alcohol) (PVA) were prepared by repeated freeze thaw method followed by in situ precipitation of zinc oxide nanoparticles within the cryogel networks. Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX) were used to characterize the nanocomposites. The morphologies of native PVA cryogels and PVA cryogel-ZnO nanocomposites were observed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) techniques. The SEM analysis suggested that cryogels show a well-defined porous morphology whereas TEM micrographs revealed the presence of nearly spherical and well separated zinc oxide nanoparticles with diameter < 100 nm. XRD results showed all relevant Bragg's reflections for crystal structure of zinc oxide nanoparticles. Thermo gravimetric-differential thermal analysis (TG-DTA) was conducted to evaluate thermal stability of the nanocomposites. Mechanical properties of nanocomposites were determined in terms of tensile strength and percent elongation. Biocompatible nature was ascertained by anti-haemolytic activity, bovine serum albumin (blood protein) adsorption and in vitro cytotoxicity tests. The prepared nanocomposites were also investigated for swelling and deswelling behaviours. The results revealed that both the swelling and deswelling process depend on the chemical composition of the nanocomposites, number of freeze-thaw cycles, pH and temperature of the swelling medium. The developed biocompatible PVA cryogel-ZnO nanocomposites were also tested for antibacterial activities against both Gram-negative and Gram-positive bacteria. - Highlights: • PVA–zinc oxide nanocomposites have been prepared with no chemical crosslinking. • The nanocomposites are completely biocompatible. • They also show antibacterial property. • The nanocomposites

Synthesis and biological evaluation of PMMA/MMT nanocomposite as denture base material.

Science.gov (United States)

Zheng, Junping; Su, Qiang; Wang, Chen; Cheng, Gang; Zhu, Ran; Shi, Jin; Yao, Kangde

2011-04-01

Inorganic-polymer nanocomposites are of significant interest for emerging materials due to their improved properties and unique combination of properties. Poly (methylmethacrylate) (PMMA)/montmorillonite (MMT) nanocomposites were prepared by in situ suspension polymerization with dodecylamine used as MMT-modifier. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the structures of the nanocomposites. Cytotoxicity test, hemolysis test, acute systemic toxicity test, oral mucous membrane irritation test, guinea-pig maximization test and mouse bone-marrow micronucleus test were used to evaluate the biocompatibility of PMMA/MMT nanocomposites. The results indicated that an exfoliated nanocomposite was achieved, and the resulting nanocomposites exhibited excellent biocompatibility as denture base material and had potential application in dental materials.

Epoxy based nanocomposites with fully exfoliated unmodified clay: mechanical and thermal properties.

Science.gov (United States)

Li, Binghai; Zhang, Xiaohong; Gao, Jianming; Song, Zhihai; Qi, Guicun; Liu, Yiqun; Qiao, Jinliang

2010-09-01

The unmodified clay has been fully exfoliated in epoxy resin with the aid of a novel ultrafine full-vulcanized powdered rubber. Epoxy/rubber/clay nanocomposites with exfoliated morphology have been successfully prepared. The microstructures of the nanocomposites were characterized by means of X-ray diffraction and transmission electron microscopy. It was found that the unmodified clay was fully exfoliated and uniformly dispersed in the resulting nanocomposite. Characterizations of mechanical properties revealed that the impact strength of this special epoxy/rubber/clay nanocomposite increased up 107% over the neat epoxy resin. Thermal analyses showed that thermal stability of the nanocomposite was much better than that of epoxy nanocomposite based on organically modified clay.

SEM technique for imaging and measuring electronic transport in nanocomposites based on electric field induced contrast

Science.gov (United States)

Jesse, Stephen [Knoxville, TN; Geohegan, David B [Knoxville, TN; Guillorn, Michael [Brooktondale, NY

2009-02-17

Methods and apparatus are described for SEM imaging and measuring electronic transport in nanocomposites based on electric field induced contrast. A method includes mounting a sample onto a sample holder, the sample including a sample material; wire bonding leads from the sample holder onto the sample; placing the sample holder in a vacuum chamber of a scanning electron microscope; connecting leads from the sample holder to a power source located outside the vacuum chamber; controlling secondary electron emission from the sample by applying a predetermined voltage to the sample through the leads; and generating an image of the secondary electron emission from the sample. An apparatus includes a sample holder for a scanning electron microscope having an electrical interconnect and leads on top of the sample holder electrically connected to the electrical interconnect; a power source and a controller connected to the electrical interconnect for applying voltage to the sample holder to control the secondary electron emission from a sample mounted on the sample holder; and a computer coupled to a secondary electron detector to generate images of the secondary electron emission from the sample.

Mesoporous binary metal oxide nanocomposites: Synthesis, characterization and decontamination of sulfur mustard

Energy Technology Data Exchange (ETDEWEB)

Praveen Kumar, J., E-mail: praveenjella10@gmail.com; Prasad, G.K.; Ramacharyulu, P.V.R.K.; Singh, Beer; Gopi, T.; Krishna, R.

2016-04-15

Mesoporous MnO{sub 2}–ZnO, Fe{sub 2}O{sub 3}–ZnO, NiO–ZnO, and CeO{sub 2}–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard. They were synthesized by precipitation pyrolysis method and characterized by means of transmission electron microscopy, scanning electron microscopy coupled with energy dispersive analysis of X rays, X ray diffraction, and nitrogen adsorption techniques. The transmission electron microscopy and nitrogen adsorption data indicated the presence of pores with diameter ranging from 10 to 70 nm in the binary metal oxide nanocomposites and these materials exhibited surface area values in the range of 76–134 m{sup 2}/g. These binary metal oxide nanocomposites demonstrated large decontamination efficiencies against sulfur mustard when compared to their single component metal oxide nanoparticles. The binary metal oxide nanocomposites effectively decontaminated sulfur mustard into relatively non toxic products such as chloro ethyl vinyl sulfide, divinyl sulfide, 1,4-oxathiane, etc. The promising decontamination properties of binary metal oxide nanocomposites against sulfur mustard were attributed to the basic sites, Lewis acid sites, and the presence of these sites was confirmed by CO{sub 2} and NH{sub 3} temperature programmed desorption. - Graphical abstract: Mesoporous MnO{sub 2}–ZnO, Fe{sub 2}O{sub 3}–ZnO, NiO–ZnO, and CeO{sub 2}–ZnO binary metal oxide nanocomposites were studied as sorbent decontaminants against sulfur mustard. - Highlights: • Binary metal oxide nanocomposites were synthesized by co-precipitation method. • They were studied as sorbent decontaminants against sulfur mustard. • They decontaminated sulfur mustard into non toxic products. • MnO{sub 2}–ZnO and CeO{sub 2}–ZnO nanocomposites showed greater decontamination efficiency.

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)

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)

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)

Polyacrolein/mesoporous silica nanocomposite: Synthesis, thermal stability and covalent lipase immobilization

Energy Technology Data Exchange (ETDEWEB)

Motevalizadeh, Seyed Farshad; Khoobi, Mehdi; Shabanian, Meisam [Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 14176 (Iran, Islamic Republic of); Asadgol, Zahra; Faramarzi, Mohammad Ali [Department of Pharmaceutical Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran 14176 (Iran, Islamic Republic of); Shafiee, Abbas, E-mail: ashafiee@ams.ac.ir [Department of Medicinal Chemistry, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 14176 (Iran, Islamic Republic of); Center of Excellence in Biothermodynamics, University of Tehran, Tehran (Iran, Islamic Republic of)

2013-12-16

In this work, new polyacrolein/MCM-41 nanocomposites with good phase mixing behavior were prepared through an emulsion polymerization technique. Mesoporous silica was synthesized by in situ assembly of tetraethyl orthosilicate (TEOS) and cetyl trimethyl ammonium bromide (CTAB). The structure and properties of polyacrolein containing nanosized MCM-41 particle (5 and 10 wt%), were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, Dynamic light scattering (DLS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N{sub 2} adsorption techniques, and thermogravimetric (TGA) analyses. The SEM images from the final powder have revealed good dispersion of the MCM-41 nanoparticles throughout polymeric matrix with no distinct voids between two phases. The results indicated that the thermal properties of the nanocomposite were enhanced by addition of MCM-41. Thermomyces lanuginosa lipase (TLL) was used as a model biocatalyst and successfully immobilized with polyacrolein and the nanocomposite via covalent bonds with the aldehyde groups. The activity between free enzyme, polyacrolein, and MCM-41 nanocomposite (10 wt%)-immobilized TLL was compared. The immobilized lipase with the nanocomposite shows better operational stability such as pH tolerance, thermal and storage stability. In addition, the immobilized lipase with the nanocomposite can be easily recovered and retained at 74% of its initial activity after 15 time reuses. - Graphical abstract: The influence of incorporation of mesoporous MCM-41 nanoparticle with polyacrolein on the thermal properties and enzyme immobilization was investigated. - Highlights: • Polyacrolein/MCM-41 nanocomposites were prepared by emulsion polymerization method. • Thermal stability and char residues in nanocomposites were improved. • Nanocomposites significant effects on immobilization of lipase.

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.

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.

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

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.

Studying the effect of graphene-ZnO nanocomposites on polymerase chain reaction

Energy Technology Data Exchange (ETDEWEB)

Sharma, Vinay, E-mail: winn201@gmail.com; Rajaura, Rajveer; Sharma, Preetam Kumar; Srivastava, Rishabh Ronin [Centre for Converging Technologies, University of Rajasthan, Jaipur 302004 (India); Sharma, Shyam Sundar [Govt. women Engineering College, Ajmer (India); Agrawal, Kailash [Centre for Converging Technologies, University of Rajasthan, Jaipur 302004 (India); Department of Botany, University of Rajasthan, Jaipur 302004 (India)

2016-05-06

An emerging area of research is improving the efficiency of the polymerase chain reaction (PCR) by using nanoparticles. With graphene nano-flakes showing promising results, in this paper we report the effect of Graphene-ZnO nanocomposites on Polymerase Chain reaction (PCR) efficiency. G-ZnO nanocomposites were efficiently synthesized via in situ chemical method. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) image confirms the formation of nanocomposites. ZnO nanoparticles of size range ~20-30 nm are uniformly attached on the graphene sheets. No amplification during PCR indicates inhibitory activity of G-ZnO nanocomposites which points the fingers at ZnO moiety of the G-ZnO composite for no amplification during our PCR reaction. Further work should concentrate on finding out the main inhibitory mechanism involved in inhibition of PCR using G-ZnO composites.

Mesoporous C/CrN and C/VN Nanocomposites Obtained by One-Pot Soft-Templating Process

Directory of Open Access Journals (Sweden)

Julien Kiener

2016-07-01

Full Text Available Nanocomposites of ordered mesoporous carbon associated with chromium nitride (CrN or vanadium nitride (VN nanoparticles were obtained by a simple one-pot synthesis based on the solvent evaporation induced self-assembly (EISA process using Pluronic triblock surfactant as soft-template and a phenol-based resin (resol as carbon precursor. These nanocomposites were characterized by X-ray diffraction, nitrogen physisorption and Transmission Electron Microscopy (TEM techniques. Electron tomography (or 3D-TEM technique was particularly useful for providing direct insight on the internal architecture of C/CrN nanocomposite. Nanocomposites showed a very well organized hexagonal mesoporous carbon structure and a relatively high concentration of nanoparticles well distributed in the porous network. The chromium and vanadium nitrides/mesoporous carbon nanocomposites could have many potential applications in catalysis, Li-ion batteries, and supercapacitors.

Organizational matters of competition in electronic educational resources

Directory of Open Access Journals (Sweden)

Ирина Карловна Войтович

2015-12-01

Full Text Available The article examines the experience of the Udmurt State University in conducting competitions of educational publications and electronic resources. The purpose of such competitions is to provide methodological support to educational process. The main focus is on competition of electronic educational resources. The technology of such contests is discussed through detailed analysis of the main stages of the contest. It is noted that the main task of the preparatory stage of the competition is related to the development of regulations on competition and the definition of criteria for selection of the submitted works. The paper also proposes a system of evaluation criteria of electronic educational resources developed by members of the contest organizing committee and jury members. The article emphasizes the importance of not only the preparatory stages of the competition, but also measures for its completion, aimed at training teachers create quality e-learning resources.

Fabrication of γ-MPS-Modified HNT-PMMA Nanocomposites by Ultrasound-Assisted Miniemulsion Polymerization

Science.gov (United States)

Buruga, Kezia; Kalathi, Jagannathan T.

2018-04-01

Halloysite nanotubes (HNTs) were modified with γ-methacryloxypropyltrimethoxysilane (γ-MPS) to improve their interaction with the polymer, and the modified HNTs (MHNTs) were subsequently used for the synthesis of MHNT-polymethylmethacrylate (PMMA) nanocomposites by miniemulsion polymerization assisted by ultrasound. Reduced agglomeration of HNTs due to modification with γ-MPS was evident from scanning electron microscopy analysis. Modification of HNTs and exfoliation of MHNTs in the polymer nanocomposite were confirmed by the presence of their respective characteristic peaks in Fourier-transform infrared spectra and x-ray diffraction patterns. Transmission electron microscopic analysis showed that the surface of the MHNTs differed significantly from that of unmodified HNTs. MHNT-PMMA nanocomposite exhibited significantly higher glass-transition temperature (T g) compared with neat PMMA or unmodified HNT-PMMA nanocomposite. Hence, such modification of HNTs along with miniemulsion polymerization assisted by ultrasound is a promising approach to achieve better dispersion of HNTs in the polymer and to obtain nanocomposites with enhanced properties.

Synthesis of polypropylene/graphite nanocomposites by means of in situ polymerization

International Nuclear Information System (INIS)

Montagna, Larissa S.; Basso, Nara R.S.

2009-01-01

The nanotechnology presents a large field for research and development of new polymeric materials based in nanocomposites. This work is related to the synthesis of nanocomposites of polypropylene with graphite as filler. The sheets of graphite in nanometer dimensions were made by means of the chemical exfoliation and thermal treatment. The synthesis of the nanocomposites was carried through by means of the in situ polymerization using a metallocene catalyst and with different amounts of inorganic load (0,5; 1 and 2%). The synthesized nanocomposites were characterized by scanning electron microscopy (SEM) and X-Ray diffraction (XRD). (author)

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.

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 ...

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.

CHALLENGES OF ELECTRONIC INFORMATION RESOURCES IN ...

African Journals Online (AJOL)

This paper discusses the role of policy for proper and efficient library services in the electronic era. It points out some of the possible dangers of embarking in electronic resources without a proper focus at hand. Thus, it calls for today's librarians and policy makers to brainstorm and come up with working policies suitable to ...

Silk fibroin/gold nanocrystals: a new example of biopolymer-based nanocomposites

Science.gov (United States)

Noinville, S.; Garnier, A.; Courty, A.

2017-05-01

The dispersion of nanoparticles in ordered polymer nanostructures can provide control over particle location and orientation, and pave the way for tailored nanomaterials that have enhanced mechanical, electrical, or optical properties. Here we used silk fibroin, a natural biopolymer, to embed gold nanocrystals (NCs), so as to obtain well-ordered structures such as nanowires and self-assembled triangular nanocomposites. Monodisperse gold NCs synthesized in organic media are mixed to silk fibroin and the obtained nanocomposites are characterized by UV-visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and Infrared spectroscopy. The optical properties study of gold NCs and silk-gold nanocomposites shows that the Surface Plasmon band is blue shifted compared to gold NCs. The size and shape of NCs gold superlattices can be well controlled by the presence of silk fibroin giving nanowires and also self-assembled triangular nanocomposites as characterized by TEM, FE-SEM and AFM. The strong interaction between gold NCs and silk fibroin is also revealed by the conformation change of silk protein in presence of gold NCs, as shown by FTIR analysis. The formation of such ordered nanocomposites (gold NCs/silk fibroin) will provide new nanoplasmonic devices.

Structural, photoconductivity, and dielectric studies of polythiophene-tin oxide nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Murugavel, S., E-mail: starin85@gmail.com; Malathi, M., E-mail: mmalathi@vit.ac.in

2016-09-15

Highlights: • Synthesis of polythiophene-tin oxide nanocomposites confirmed by FTIR and EDAX. • SEM shows SnO{sub 2} nanoparticles embedded within polythiophene matrix. • Stability and isoelectric point suggest nanoparticle–matrix interaction. • High dielectric constant due to high Maxwell–Wagner interfacial polarization. - Abstract: Polythiophene-tinoxide (PT-SnO{sub 2}) nanocomposites were prepared by in situ chemical oxidative polymerization, in the presence of various concentrations of SnO{sub 2} nanoparticles. Samples were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy and Zeta potential measurements. Morphologies and elemental compositions were investigated by transmission electron microscopy, field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. The photoconductivity of the nanocomposites was studied by field-dependent dark and photo conductivity measurements. Their dielectric properties were investigated using dielectric spectroscopy, in the frequency range of 1kHz–1 MHz. The results indicated that the SnO{sub 2} nanoparticles in the PT-SnO{sub 2} nanocomposite were responsible for its enhanced dielectric performance.

Laser additive manufacturing bulk graphene-copper nanocomposites.

Science.gov (United States)

Hu, Zengrong; Chen, Feng; Lin, Dong; Nian, Qiong; Parandoush, Pedram; Zhu, Xing; Shao, Zhuqiang; Cheng, Gary J

2017-11-03

The exceptional mechanical properties of graphene make it an ideal nanofiller for reinforcing metal matrix composites (MMCs). In this work, graphene-copper (Gr-Cu) nanocomposites have been fabricated by a laser additive manufacturing process. Transmission electron microscopy (TEM), x-ray diffraction (XRD) and Raman spectroscopy were utilized to characterize the fabricated nanocomposites. The XRD, Raman spectroscopy, energy dispersive spectroscopy and TEM results demonstrated the feasibility of laser additive manufacturing of Gr-Cu nanocomposites. The microstructures were characterized by high resolution TEM and the results further revealed the interface between the copper matrix and graphene. With the addition of graphene, the mechanical properties of the composites were enhanced significantly. Nanoindentation tests showed that the average modulus value and hardness of the composites were 118.9 GPa and 3 GPa respectively; 17.6% and 50% increases were achieved compared with pure copper, respectively. This work demonstrates a new way to manufacture graphene copper nanocomposites with ultra-strong mechanical properties and provides alternatives for applications in electrical and thermal conductors.

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.

Dielectric spectroscopy of Ag-starch nanocomposite films

Science.gov (United States)

Meena; Sharma, Annu

2018-04-01

In the present work Ag-starch nanocomposite films were fabricated via chemical reduction route. The formation of Ag nanoparticles was confirmed using transmission electron microscopy (TEM). Further the effect of varying concentration of Ag nanoparticles on the dielectric properties of starch has been studied. The frequency response of dielectric constant (ε‧), dielectric loss (ε″) and dissipation factor tan(δ) has been studied in the frequency range of 100 Hz to 1 MHz. Dielectric data was further analysed using Cole-Cole plots. The dielectric constant of starch was found to be 4.4 which decreased to 2.35 in Ag-starch nanocomposite film containing 0.50 wt% of Ag nanoparticles. Such nanocomposites with low dielectric constant have potential applications in microelectronic technologies.

Metallic Nanocomposites as Next-Generation Thermal Interface Materials: Preprint

Energy Technology Data Exchange (ETDEWEB)

Feng, Xuhui [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Narumanchi, Sreekant V [National Renewable Energy Laboratory (NREL), Golden, CO (United States); King, Charles C [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Nagabandi, Nirup [Texas A& M University; Oh, Jun K. [Texas A& M University; Akbulut, Mustafa [Texas A& M University; Yegin, Cengiz [Texas A& M University

2017-09-14

Thermal interface materials (TIMs) are an integral and important part of thermal management in electronic devices. The electronic devices are becoming more compact and powerful. This increase in power processed or passing through the devices leads to higher heat fluxes and makes it a challenge to maintain temperatures at the optimal level during operation. Herein, we report a free standing nanocomposite TIM in which boron nitride nanosheets (BNNS) are uniformly dispersed in copper matrices via an organic linker, thiosemicarbazide. Integration of these metal-organic-inorganic nanocomposites was made possible by a novel electrodeposition technique where the functionalized BNNS (f-BNNS) experience the Brownian motion and reach the cathode through diffusion, while the nucleation and growth of the copper on the cathode occurs via the electrochemical reduction. Once the f-BNNS bearing carbonothioyl/thiol groups on the terminal edges come into the contact with copper crystals, the chemisorption reaction takes place. We performed thermal, mechanical, and structural characterization of these nanocomposites using scanning electron microcopy (SEM), diffusive laser flash (DLF) analysis, phase-sensitive transient thermoreflectence (PSTTR), and nanoindentation. The nanocomposites exhibited a thermal conductivity ranging from 211 W/mK to 277 W/mK at a filler mass loading of 0-12 wt.percent. The nanocomposites also have about 4 times lower hardness as compared to copper, with values ranging from 0.27 GPa to 0.41 GPa. The structural characterization studies showed that most of the BNNS are localized at grain boundaries - which enable efficient thermal transport while making the material soft. PSTTR measurements revealed that the synergistic combinations of these properties yielded contact resistances on the order of 0.10 to 0.13 mm2K/W, and the total thermal resistance of 0.38 to 0.56 mm2K/W at bondline thicknesses of 30-50 um. The coefficient of thermal expansion (CTE) of the

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)

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)

Preparation of BiVO4-Graphene Nanocomposites and Their Photocatalytic Activity

Directory of Open Access Journals (Sweden)

Xuan Xu

2014-01-01

Full Text Available We prepared BiVO4-graphene nanocomposites by using a facile single-step method and characterized the material by x-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, ultraviolet-visible diffuse-reflection spectroscopy, and three-dimensional fluorescence spectroscopy. The results show that graphene oxide in the catalyst was thoroughly reduced. The BiVO4 is densely dispersed on the graphene sheets, which facilitates the transport of electrons photogenerated in BiVO4, thereby leading to an efficient separation of photogenerated carriers in the coupled graphene-nanocomposite system. For degradation of rhodamine B dye under visible-light irradiation, the photocatalytic activity of the synthesized nanocomposites was over ∼20% faster than for pure BiVO4 catalyst. To study the contribution of electrons and holes in the degradation reaction, silver nitrate and potassium sodium tartrate were added to the BiVO4-graphene photocatalytic reaction system as electron-trapping agent and hole-trapping agent, respectively. The results show that holes play the main role in the degradation of rhodamine B.

A tunnelling study on polymer/1T-LixTaS2 layered nanocomposites

International Nuclear Information System (INIS)

Enomoto, Hiroyuki; Takai, Hiroyuki; Ozaki, Hajime; Lerner, Michael M

2004-01-01

Electronic structures near the Fermi level of polymer/1T-Li x TaS 2 layered nanocomposites have been studied by tunnelling spectroscopy. Polymer/1T-Li x TaS 2 layered nanocomposites were synthesized by using the exfoliation-adsorption technique. Single crystals of 1T-TaS 2 were used as host materials. Poly(ethylene oxide) (PEO) and poly(ethylenimine) (PEI) with different molecular weights were adopted as guest intercalants. Powder x-ray diffraction patterns showed that all samples of the polymer/1T-Li x TaS 2 layered nanocomposites contain organic polymer between all individual 1T-TaS 2 sheets. Although 1T-TaS 2 single crystal is well known to show quite unique temperature dependences of the resistivity due to the charge density wave (CDW), the resistivities of all polymer/1T-Li x TaS 2 nanocomposites showed semiconductor-like temperature dependences. The tunnelling spectra of polymer/1T-Li x TaS 2 nanocomposites revealed that the CDW gap disappears in the density of states near the Fermi level of polymer/1T-Li x TaS 2 nanocomposites and their electronic structures show a metallic behaviour

Graphene/SnO2 nanocomposite-modified electrode for electrochemical detection of dopamine

OpenAIRE

R. Nurzulaikha; H.N. Lim; I. Harrison; S.S. Lim; A. Pandikumar; N.M. Huang; S.P. Lim; G.S.H. Thien; N. Yusoff; I. Ibrahim

2015-01-01

A graphene-tin oxide (G-SnO2) nanocomposite was prepared via a facile hydrothermal route using graphene oxide and Sn precursor solution without addition of any surfactant. The hydrothermally synthesized G-SnO2 nanocomposite was characterized using a field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). A homogeneous deposition of SnO2 nanoparticles with an average partic...

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 (T_g) 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.

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 ...

Use of Electronic Resources in a Private University in Nigeria ...

African Journals Online (AJOL)

The study examined awareness and constraints in the use of electronic resources by lecturers and students of Ajayi Crowther University, Oyo, Nigeria. It aimed at justifying the resources expended in the provision of electronic resources in terms of awareness, patronage and factors that may be affecting awareness and use ...

Electronic Resources Management System: Recommendation Report 2017

KAUST Repository

Ramli, Rindra M.

2017-05-01

This recommendation report provides an overview of the selection process for the new Electronic Resources Management System. The library has decided to move away from Innovative Interfaces Millennium ERM module. The library reviewed 3 system as potential replacements namely: Proquest 360 Resource Manager, Ex Libris Alma and Open Source CORAL ERMS. After comparing and trialling the systems, it was decided to go for Proquest 360 Resource Manager.

Simple One-Step Method to Synthesize Polypyrrole-Indigo Carmine-Silver Nanocomposite

Directory of Open Access Journals (Sweden)

Lara Fernandes Loguercio

2016-01-01

Full Text Available A nanocomposite of indigo carmine doped polypyrrole/silver nanoparticles was obtained by a one-step electrochemical process. The nanocomposite was characterized by scanning electron microscopy, infrared spectroscopy, ultraviolet-visible-near infrared spectroscopy, and cyclic voltammetry. The simple one-step process allowed the growth of silver nanoparticles during the polymerization of polypyrrole, resulting in films with electrochromic behavior and improved electroactivity. In addition, polypyrrole chains in the nanocomposite were found to present longer conjugation length than pristine polypyrrole films.

Methyl methacrylate oligomerically-modified clay and its poly(methyl methacrylate) nanocomposites

International Nuclear Information System (INIS)

Zheng Xiaoxia; Jiang, David D.; Wilkie, Charles A.

2005-01-01

A methyl methacrylate oligomerically-modified clay was used to prepare poly(methyl methacrylate) clay nanocomposites by melt blending and the effect of the clay loading level on the modified clay and corresponding nanocomposite was studied. These nanocomposites were characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis and cone calorimetry. The results show a mixed intercalated/delaminated morphology with good nanodispersion. The compatibility between the methylacrylate-subsituted clay and poly(methyl methacrylate) (PMMA) are greatly improved compared to other oligomerically-modified clays

A quantum dot-spore nanocomposite pH sensor.

Science.gov (United States)

Zhang, Xingya; Li, Zheng; Zhou, Tao; Zhou, Qian; Zeng, Zhiming; Xu, Xiangdong; Hu, Yonggang

2016-04-01

A new quantum dot (QD)-based pH sensor design is investigated. The sensor is synthesized based on the self-assembly of green QDs onto treated spores to form QD@spore nanocomposites. The nanocomposites are characterized using laser scanning confocal microscopy, transmission electron microscope, and fluorescence spectroscopy, among others. Fluorescence measurements showed that these nanocomposites are sensitive to pH in a broad pH range of 5.0-10.0. The developed pH sensors have been satisfactorily applied for pH estimation of real samples and are comparable with those of the commercial assay method, indicating the potential practical application of the pH sensors. Copyright © 2015 Elsevier B.V. All rights reserved.

Double Walled Carbon Nanotube/TiO2 Nanocomposites for Photocatalytic Dye Degradation

Directory of Open Access Journals (Sweden)

Alex T. Kuvarega

2016-01-01

Full Text Available Double walled carbon nanotube (DWCNT/N,Pd codoped TiO2 nanocomposites were prepared by a modified sol-gel method and characterised using FTIR, Raman spectroscopy, TGA, DRUV-Vis, XRD, SEM, and TEM analyses. TEM images showed unique pearl-bead-necklace structured morphologies at higher DWCNT ratios. The nanocomposite materials showed characteristic anatase TiO2 Raman bands in addition to the carbon nanotube D and G bands. Red shifts in the UV-Vis absorption edge were observed at low DWCNT percentages. The photocatalytic activity of DWCNT/N,Pd TiO2 nanocomposite was evaluated by the photocatalytic degradation of eosin yellow under simulated solar light irradiation and the 2% DWCNT/N,Pd TiO2 nanocomposite showed the highest photoactivity while the 20% DWCNT/N,Pd TiO2 hybrid was the least efficient. The photocatalytic enhancement was attributed to the synergistic effects of the supporting and electron channeling role of the DWCNTs as well as the electron trapping effects of the platinum group metal. These phenomena favour the separation of the photogenerated electron-hole pairs, reducing their recombination rate, which consequently lead to significantly enhanced photoactivity.

Comparative sensing of aldehyde and ammonia vapours on synthetic polypyrrole-Sn(IVarsenotungstate nanocomposite cation exchange material

Directory of Open Access Journals (Sweden)

Asif Ali Khan

2017-06-01

Full Text Available Polypyrrole-Sn(IVarsenotungstate (PPy-SnAT conductive nanocomposite cation exchange have been synthesized by in-situ chemical oxidative polymerization of polypyrrole with Sn(IVarsenotungstate (SnAT. PPy-SnAT nanocomposite was characterized by Fourier transform infra-red spectroscopy (FTIR, X-Ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, energy-dispersive x-ray (EDX and thermogravimetric analysis (TGA. The ion exchange capacity (IEC and DC electrical conductivity of nanocomposite was found to be 2.50 meq/g and 5.05 × 10−1 S/cm respectively. The nanocomposite showed appreciable isothermal stability in terms of DC electrical conductivity retention under ambient condition up to 130 °C. The nanocomposite cation exchange based sensor for detection of formaldehyde and ammonia vapours were fabricated at room temperature. It was revealed that the resistivity of the nanocomposite increases on exposure to higher percent concentration of ammonia and lower concentration of formaldehyde at room temperature (25 °C.

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

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.

Facile synthesis, dielectric properties and electrocatalytic activities of PMMA-NiFe2O4 nanocomposite

International Nuclear Information System (INIS)

Maji, Pranabi; Choudhary, Ram Bilash

2017-01-01

The paper deals with the dielectric and catalytic properties of poly (methyl methacrylate)-nikel ferrite (PMMA-NiFe 2 O 4 ) nanocomposite. The nanocomposite was prepared by using a general and facile synthesis strategy. Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectra confirmed the formation of PMMA-NiFe 2 O 4 nanocomposite. Field effect scanning electron microscopic (FESEM) and transmission electron microscopic (TEM) images revealed that NiFe 2 O 4 nanoparticles were uniformly distributed and were tightly adhered with PMMA matrix owing to surface modification with 3-methacryloyloxy propyl trimethoxy silane (KH-570). Thermal stability was enhanced by incorporation of NiFe 2 O 4 nanofillers. The nanocomposite showed high dielectric constant and low dielectric loss. The achieved dielectric and thermal property inferred the potential application of this material in energy storage and embedded electronics devices. Further, the as prepared nanocomposite also offered a remarkable electrochemical performance towards hydrogen peroxide (H 2 O 2 ) sensing. - Highlights: • PMMA-NiFe 2 O 4 nanocomposite was synthesized via free radical polymerization. • The nanocomposite exhibited high value of dielectric constant (51) and tanδ (0.3). • Thermal stability of the PMMA matrix was improved by the incorporation of NiFe 2 O 4. • The H 2 O 2 detection limit was estimated 44 μM when signal to noise (S/N) ration was 3. • The electrochemical sensitivity of H 2 O 2 was calculated 0.6727 μA mM -1 .

use of electronic resources by graduate students of the department

African Journals Online (AJOL)

respondent's access electronic resources from the internet via Cybercafé .There is a high ... KEY WORDS: Use, Electronic Resources, Graduate Students, Cybercafé. INTRODUCTION ... Faculty of Education, University of Uyo, Uyo. Olu Olat ...

Hierarchical carbon nanopetal/polypyrrole nanocomposite electrodes with brush-like architecture for supercapacitors.

Science.gov (United States)

Cherusseri, Jayesh; Kar, Kamal K

2016-03-28

Hierarchical 3D nanocomposite electrodes with tube brush-like morphology are synthesized by electrochemically depositing polypyrrole (PPY) on carbon nanopetal (CNP) coated carbon fibers (CFs). Initially CNPs are synthesized on CF substrate by chemical vapour deposition. The CNPs synthesized on CF (CNPCF) are further used as an electrically conducting large surface area bearing template for the electropolymerization of PPY in order to fabricate CNPCF-PPY nanocomposite electrodes for supercapacitors (SCs). The CF in CNPCF-PPY nanocomposite functions as (i) a mechanical support for the CNPs, (ii) a current collector for the SC cell and also (iii) to prevent the agglomeration of CNPs within the CNPCF-PPY nanocomposite. Transmission electron microscopy and scanning electron microscopy are used to examine the surface morphology of CNPCF-PPY nanocomposites. The chemical structure of the nanocomposites is analysed by Fourier transform infrared spectroscopy. X-Ray photoelectron spectroscopy has been used to understand the chemical bonding states of the hierarchical CNPCF-PPY nanocomposites. The electrochemical properties of symmetric type CNPCF-PPY SC cells are examined by electrochemical impedance spectroscopy, cyclic voltammetry and galvanostatic charge-discharge measurements. The hierarchical CNPCF-PPY SC exhibits a maximum gravimetric capacitance of 280.4 F g(-1) and an area specific capacitance of 210.3 mF cm(-2) at a current density of 0.42 mA cm(-2). The CNPCF-PPY SC cell exhibits good cycling stability of more than 5000 cycles. The present study proclaims the development of a novel lightweight SC with high-performance.

Transportation of drug–gold nanocomposites by actinomyosin motor system

International Nuclear Information System (INIS)

Kaur, Harsimran; Chaudhary, Archana; Kaur, Inderpreet; Singh, Kashmir; Bharadwaj, Lalit M.

2011-01-01

Nanotechnology is playing an important role in drug delivery to overcome limitations of conventional drug delivery systems in terms of solubility, in vivo stability, pharmacokinetics, and bio-distribution. The controlled transportation of drug into the cell and within the cell is a major challenge to be addressed. Cellular molecular motors have been exploited for their cargo carrying capacity for various applications including engineering and health care. Combination of nanotechnology and biomolecular motors can address some of the challenges in drug delivery. In the present study, transportation of drug nanocomposites has been demonstrated. Nanocomposites of 6-mercaptopurine and levodopa drugs (cancer and Parkinson’s disease, respectively) were prepared with gold nanoparticles (GNPs) by covalent attachment and these nanocomposites were attached to actin filaments. These nanocomposites were in-turn transported by actin filaments on myosin tracks. Characterization of drug nanocomposites formation was done by UV–Vis spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and confocal microscopy. GNP composites of 6-mercaptopurine and levodopa were formed by sulfide and amide bond formation, respectively. Average velocity of actin filament attached to nanocomposites was found to be 3.17 and 3.89 μm/s for levodopa and 6-mercaptopurine, respectively, as compared to actin filaments with velocity of 4.0–6.0 μm/s. Three concepts have been proposed for the study of drug transportation into the cell based on polycationic complex formation, interaction of actin with cellular myosin and Biomolecular Adaptor for Retrograde Transport (BART) technology. The aspects of this study heads toward the development of an approach to utilize molecular motors for nanoscale transportation endogenously.

Transportation of drug-gold nanocomposites by actinomyosin motor system

Science.gov (United States)

Kaur, Harsimran; Chaudhary, Archana; Kaur, Inderpreet; Singh, Kashmir; Bharadwaj, Lalit M.

2011-06-01

Nanotechnology is playing an important role in drug delivery to overcome limitations of conventional drug delivery systems in terms of solubility, in vivo stability, pharmacokinetics, and bio-distribution. The controlled transportation of drug into the cell and within the cell is a major challenge to be addressed. Cellular molecular motors have been exploited for their cargo carrying capacity for various applications including engineering and health care. Combination of nanotechnology and biomolecular motors can address some of the challenges in drug delivery. In the present study, transportation of drug nanocomposites has been demonstrated. Nanocomposites of 6-mercaptopurine and levodopa drugs (cancer and Parkinson's disease, respectively) were prepared with gold nanoparticles (GNPs) by covalent attachment and these nanocomposites were attached to actin filaments. These nanocomposites were in-turn transported by actin filaments on myosin tracks. Characterization of drug nanocomposites formation was done by UV-Vis spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and confocal microscopy. GNP composites of 6-mercaptopurine and levodopa were formed by sulfide and amide bond formation, respectively. Average velocity of actin filament attached to nanocomposites was found to be 3.17 and 3.89 μm/s for levodopa and 6-mercaptopurine, respectively, as compared to actin filaments with velocity of 4.0-6.0 μm/s. Three concepts have been proposed for the study of drug transportation into the cell based on polycationic complex formation, interaction of actin with cellular myosin and Biomolecular Adaptor for Retrograde Transport (BART) technology. The aspects of this study heads toward the development of an approach to utilize molecular motors for nanoscale transportation endogenously.

Transportation of drug-gold nanocomposites by actinomyosin motor system

Energy Technology Data Exchange (ETDEWEB)

Kaur, Harsimran, E-mail: microsimbac@gmail.com; Chaudhary, Archana; Kaur, Inderpreet [Council of Scientific and Industrial Research (CSIR), Biomolecular Electronics and Nanotechnology Division (BEND), Central Scientific Instruments Organization - CSIO (India); Singh, Kashmir [Panjab University, Department of Biotechnology (India); Bharadwaj, Lalit M. [Council of Scientific and Industrial Research (CSIR), Biomolecular Electronics and Nanotechnology Division (BEND), Central Scientific Instruments Organization - CSIO (India)

2011-06-15

Nanotechnology is playing an important role in drug delivery to overcome limitations of conventional drug delivery systems in terms of solubility, in vivo stability, pharmacokinetics, and bio-distribution. The controlled transportation of drug into the cell and within the cell is a major challenge to be addressed. Cellular molecular motors have been exploited for their cargo carrying capacity for various applications including engineering and health care. Combination of nanotechnology and biomolecular motors can address some of the challenges in drug delivery. In the present study, transportation of drug nanocomposites has been demonstrated. Nanocomposites of 6-mercaptopurine and levodopa drugs (cancer and Parkinson's disease, respectively) were prepared with gold nanoparticles (GNPs) by covalent attachment and these nanocomposites were attached to actin filaments. These nanocomposites were in-turn transported by actin filaments on myosin tracks. Characterization of drug nanocomposites formation was done by UV-Vis spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and confocal microscopy. GNP composites of 6-mercaptopurine and levodopa were formed by sulfide and amide bond formation, respectively. Average velocity of actin filament attached to nanocomposites was found to be 3.17 and 3.89 {mu}m/s for levodopa and 6-mercaptopurine, respectively, as compared to actin filaments with velocity of 4.0-6.0 {mu}m/s. Three concepts have been proposed for the study of drug transportation into the cell based on polycationic complex formation, interaction of actin with cellular myosin and Biomolecular Adaptor for Retrograde Transport (BART) technology. The aspects of this study heads toward the development of an approach to utilize molecular motors for nanoscale transportation endogenously.

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.

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.

Reduced graphene oxide/CeO{sub 2} nanocomposite with enhanced photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Kaur, Jasmeet, E-mail: jasmeet.dayal@gmail.com; Anand, Kanika; Singh, Gurpreet; Hastir, Anita; Virpal,; Singh, Ravi Chand [Laboratory For Sensors and Physics Education, Department of Physics, GND University, Amritsar-143005 (India); Anand, Kanica [Semiconductors Laboratory, Department of Physics, GND University, Amritsar– 143005 (India)

2015-05-15

In this work, reduced graphene oxide /cerium oxide (RGO/CeO{sub 2}) nanocomposite was synthesized by in situ reduction of cerium nitrate Ce(NO{sub 3}){sub 3}·6H{sub 2}O in the presence of graphene oxide by hydrazine hydrate (N{sub 2}H{sub 4}.H{sub 2}O). The intrinsic characteristics of as-prepared nanocomposite were studied using powder x-ray diffraction (XRD), Raman spectroscopy and field-emission scanning electron microscopy (FESEM). The photocatalytic degradation of methylene blue (MB) was employed as a model reaction to evaluate the photocatalytic activity of the RGO/CeO{sub 2} nanocomposite. The as-obtained RGO/CeO{sub 2} nanocomposite displays a significantly enhanced photocatalytic degradation of MB dye in comparison with bare CeO{sub 2} nanoparticles under sunlight irradiation, which can be attributed to the improved separation of electron-hole pairs and enhanced adsorption performance due to presence of RGO.

Novel one-step route for synthesizing CdS/polystyrene nanocomposite hollow spheres.

Science.gov (United States)

Wu, Dazhen; Ge, Xuewu; Zhang, Zhicheng; Wang, Mozhen; Zhang, Songlin

2004-06-22

CdS/polystyrene nanocomposite hollow spheres with diameters between 240 and 500 nm were synthesized under ambient conditions by a novel microemulsion method in which the polymerization of styrene and the formation of CdS nanoparticles were initiated by gamma-irradiation. The product was characterized by transmission electron microscopy (TEM), field-emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA), which show the walls of the hollow spheres are porous and composed of polystyrene containing homogeneously dispersed CdS nanoparticles. The quantum-confined effect of the CdS/polystyrene nanocomposite hollow spheres is confirmed by the ultraviolet-visible (UV-vis) and photoluminescent (PL) spectra. We propose that the walls of these nanocomposite hollow spheres originate from the simultaneous synthesis of polystyrene and CdS nanoparticles at the interface of microemulsion droplets. This novel method is expected to produce various inorganic/polymer nanocomposite hollow spheres with potential applications in the fields of materials science and biotechnology.

Graphene/SnO2 nanocomposite-modified electrode for electrochemical detection of dopamine

Directory of Open Access Journals (Sweden)

R. Nurzulaikha

2015-09-01

Full Text Available A graphene-tin oxide (G-SnO2 nanocomposite was prepared via a facile hydrothermal route using graphene oxide and Sn precursor solution without addition of any surfactant. The hydrothermally synthesized G-SnO2 nanocomposite was characterized using a field emission scanning electron microscope (FESEM, high resolution transmission electron microscope (HRTEM, X-ray diffraction (XRD, and energy dispersive spectroscopy (EDS. A homogeneous deposition of SnO2 nanoparticles with an average particle size of 10 nm on the graphene was observed in the FESEM and HRTEM images. The G-SnO2 nanocomposite was used to fabricate a modified electrode for the electrochemical detection of dopamine (DA in the presence of ascorbic acid (AA. Differential pulse voltammetry (DPV showed a limit of detection (LoD of 1 μM (S/N = 3 in the presence of ascorbic acid (AA. Keywords: Graphene, Tin oxide, Nanocomposite, Electrochemical sensor, Biosensor, Dopamine

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.

Polymer-Ag nanocomposites with enhanced antimicrobial activity against bacterial infection.

Science.gov (United States)

Mei, Lin; Lu, Zhentan; Zhang, Xinge; Li, Chaoxing; Jia, Yanxia

2014-09-24

Herein, a nontoxic nanocomposite is synthesized by reduction of silver nitrate in the presence of a cationic polymer displaying strong antimicrobial activity against bacterial infection. These nanocomposites with a large concentration of positive charge promote their adsorption to bacterial membranes through electrostatic interaction. Moreover, the synthesized nanocomposites with polyvalent and synergistic antimicrobial effects can effectively kill both Gram-positive and Gram-negative bacteria without the emergence of bacterial resistance. Morphological changes obtained by transmission electron microscope observation show that these nanocomposites can cause leakage and chaos of intracellular contents. Analysis of the antimicrobial mechanism confirms that the lethal action of nanocomposites against the bacteria started with disruption of the bacterial membrane, subsequent cellular internalization of the nanoparticles, and inhibition of intracellular enzymatic activity. This novel antimicrobial material with good cytocompatibility promotes healing of infected wounds in diabetic rats, and has a promising future in the treatment of other infectious diseases.

MoO2-ordered mesoporous carbon nanocomposite as an anode material for lithium-ion batteries.

Science.gov (United States)

Zeng, Lingxing; Zheng, Cheng; Deng, Cuilin; Ding, Xiaokun; Wei, Mingdeng

2013-03-01

In the present work, the nanocomposite of MoO2-ordered mesoporous carbon (MoO2-OMC) was synthesized for the first time using a carbon thermal reduction route and the mesoporous carbon as the nanoreactor. The synthesized nanocomposite was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), N2 adsorption-desorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) measurements. Furthermore, this nanocomposite was used as an anode material for Li-ion intercalation and exhibited large reversible capacity, high rate performance, and good cycling stability. For instance, a high reversible capacity of 689 mAh g(-1) can remain after 50 cycles at a current density of 50 mA g(-1). It is worth mentioning that the MoO2-OMC nanocomposite electrode can attain a high reversible capacity of 401 mAh g(-1) at a current density as high as 2 A g(-1). These results might be due to the intrinsic characteristics of nanocomposite, which offered a better accommodation of the strain and volume changes and a shorter path for Li-ion and electron transport, leading to the improved capacity and enhanced rate capability.

Poly (Lactic Acid)/Layered Silicate Nanocomposite Films: Effect of Irradiation

Energy Technology Data Exchange (ETDEWEB)

Dadbin, S.; Naimian, F.; Akhavan, A.; Hasanpoor, S., E-mail: sdadbin@yahoo.com, E-mail: sdadbin@aeoi.org.ir [Atomic Energy Organization of Iran (AEOI), Nuclear Science and Technology Research Institute, P.O. Box 11365-8486, Tehran, North Kargar (Iran, Islamic Republic of)

2010-07-01

Poly (Lactic acid) –layered silicate nanocomposite films were prepared by solution casting method. The films were irradiated with Co{sup 60} radiation facility at dose of 30 kGy. The effect of gamma irradiation on mechanical properties of the neat PLA and nanocomposites was evaluated by data obtained from tensile testing measurements. The tensile strength of the irradiated PLA films increased with addition of 1 wt% Triallyl Cyanurate (TAC) indicating crosslink formation. Significant ductile behavior was observed in the PLA nanocomposites containing 4 pph of nanoclay. Incorporation of nanoclay particles in the PLA matrix stimulated crystal growth as it was studied by differential scanning calorimetry (DSC). The morphology of the nanocomposites characterized by transmission electron microscopy (TEM) and X- ray diffraction (XRD) revealed an exfoliated morphology in the PLA nanocomposite films containing 4 pph of nanoclay. Only very small changes were observed in the chemical structure of the irradiated samples as it was investigated by Fourier transform infrared (FTIR) spectroscopy. Enzymatic degradation rate of PLA and its nanocomposite decreased with increasing crystallinity of the samples. The rate of weight loss was also affected by the morphology of the nanocomposites. (author)

Poly (Lactic Acid)/Layered Silicate Nanocomposite Films: Effect of Irradiation

International Nuclear Information System (INIS)

Dadbin, S.; Naimian, F.; Akhavan, A.; Hasanpoor, S.

2010-01-01

Poly (Lactic acid) –layered silicate nanocomposite films were prepared by solution casting method. The films were irradiated with Co 60 radiation facility at dose of 30 kGy. The effect of gamma irradiation on mechanical properties of the neat PLA and nanocomposites was evaluated by data obtained from tensile testing measurements. The tensile strength of the irradiated PLA films increased with addition of 1 wt% Triallyl Cyanurate (TAC) indicating crosslink formation. Significant ductile behavior was observed in the PLA nanocomposites containing 4 pph of nanoclay. Incorporation of nanoclay particles in the PLA matrix stimulated crystal growth as it was studied by differential scanning calorimetry (DSC). The morphology of the nanocomposites characterized by transmission electron microscopy (TEM) and X- ray diffraction (XRD) revealed an exfoliated morphology in the PLA nanocomposite films containing 4 pph of nanoclay. Only very small changes were observed in the chemical structure of the irradiated samples as it was investigated by Fourier transform infrared (FTIR) spectroscopy. Enzymatic degradation rate of PLA and its nanocomposite decreased with increasing crystallinity of the samples. The rate of weight loss was also affected by the morphology of the nanocomposites. (author)

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.

Preparation and thermal performance of paraffin/Nano-SiO2 nanocomposite for passive thermal protection of electronic devices

International Nuclear Information System (INIS)

Wang, Yaqin; Gao, Xuenong; Chen, Peng; Huang, Zhaowen; Xu, Tao; Fang, Yutang; Zhang, Zhengguo

2016-01-01

Highlights: • Three types of paraffin/nano-SiO 2 nanocomposites were prepared and characterized. • Thermo-physical properties of these composites were determined and compared. • One composite with lower thermal conductivity showed better thermal insulation properties. • This composite was identified as thermal insulation material for electronic components. - Abstract: In this paper, three grades of nano silicon dioxide (nano-SiO 2 ), NS1, NS2 and NS3, were mixed into paraffin to prepare nanocomposites as novel insulation materials for electronic passive thermal protection applications. The optimal mass percentages of paraffin for the three composites, NS1P, NS2P and NS3P, were determined to be 75%, 70% and 65%, respectively. Investigations by means of scanning electron micrographs (SEM), differential scanning calorimeter (DSC), thermogravimetric analysis (TG), hot disk analyzer and thermal protection performance tests were devoted to the morphology, thermal properties and thermal protection performance analysis of composites. Experimental results showed that paraffin uniformly distributed into the pores and on the surface of nano-SiO 2 . Melting points of composites declined and experimental latent heat became lower than the calculated values with the decrease of nano-SiO 2 pore size. The NS1P composite had larger thermal storage capacity, better reliability and stability compared with NS2P and NS3P. In addition, compared with 90% wt.% paraffin/EG composite, the incorporation of NS1 (25 wt.%) into paraffin caused not only 63.2% reduction in thermal conductivity, but also 21.8% increase in thermal protection time affected by the ambient temperature. Thus those good properties confirmed that NS1P (75 wt.%) composite was a viable candidate for protecting electronic devices under high temperature environment.

High oxygen nanocomposite barrier films based on xylan and nanocrystalline cellulose

Science.gov (United States)

Amit Saxena; Thomas J. Elder; Jeffrey Kenvin; Arthur J. Ragauskas

2010-01-01

The goal of this work is to produce nanocomposite film with low oxygen permeability by casting an aqueous solution containing xylan, sorbitol and nanocrystalline cellulose. The morphology of the resulting nanocomposite films was examined by scanning electron microscopy and atomic force microscopy which showed that control films containing xylan and sorbitol had a more...

New nanocomposites of polystyrene with polyaniline doped with lauryl sulfuric acid

Science.gov (United States)

Pud, A. A.; Nikolayeva, O. A.; Vretik, L. O.; Noskov, Yu. V.; Ogurtsov, N. A.; Kruglyak, O. S.; Fedorenko, E. A.

2017-08-01

This work is concentrated on synthesis and investigation of new core-shell nanocomposites of polystyrene (PS) with doped polyaniline (PANI). The latex containing PS nanoparticles with sizes of 15-30 nm was prepared by microemulsion polymerization of styrene in water media. The PS/PANI nanocomposites were synthesized by chemical oxidative polymerization of aniline in the PS latex media in a presence of lauryl sulfuric acid (LSA), which served as both dopant and plasticizer. The real content of PANI in the synthesized nanocomposites was determined by UV-Vis spectroscopy method. The composition of the nanocomposites and oxidation state of the doped polyaniline were characterized by FTIR spectroscopy. The core-shell morphology of the nanocomposite nanoparticles was proved by transmission and scanning electron microscopy. It was found that conductivity and thermal behavior in air of these nanocomposites not only nonlinearly depended on the doped polyaniline content but also were strongly effected both by plasticizing properties of the acid-dopant and presence of the polyaniline shell. A possibility of application of these nanocomposites as sensor materials has been demonstrated.

Synthesis and utilization of poly (methylmethacrylate nanocomposites based on modified montmorillonite

Directory of Open Access Journals (Sweden)

Ahmed M. Youssef

2017-07-01

Full Text Available 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 better thermal stability than pristine PMMA which make it suitable for packaging applications. Furthermore, this nanocomposite reveals tremendous affinity for removing pesticides from aquatic solutions. The data obtained from GC/ECD gas liquid chromatography illustrated that the removal efficiency of PMMA/Mt-CTA nanocomposites for organochlorine pesticides (OCPs varied from 73.65% to 99.36% that make it as a new method for water treatment. Also, the antimicrobial activity of the Mt-CTA and PMMA/Mt-CTA nanocomposites was evaluated by the inhibitory zone tests and revealed good activity against Escherichia coli and Staphylococcus aureus, which makes it suitable materials for packaging applications.

Polymeric phase change nanocomposite (PMMA/Fe:ZnO) for electronic packaging application

Science.gov (United States)

Maji, Pranabi; Choudhary, Ram Bilash; Majhi, Malati

2018-01-01

This paper reported the effect of Fe-doped ZnO (Fe:ZnO) nanoparticles on the structural, morphological, thermal, optical and dielectric properties of PMMA matrix. Fe-doped ZnO nanoparticle was synthesized by co-precipitation method, after its surface modification incorporated into the PMMA matrix by free radical polymerization method. The phase analysis and crystal structure were investigated by XRD and FTIR technique. These studies confirmed the chemical structure of the PMMA/Fe:ZnO nanocomposite. FESEM image showed the pyramidal shape and high porosity of PMMA/Fe:ZnO nanocomposite. Thermal analysis of the sample was carried out by thermo-gravimetric analyzer. PMMA/Fe:ZnO nanocomposite was found to have better thermal stability compared to pure one. Broadband dielectric spectroscopic technique was used to investigate the transition of electrical properties of Fe-doped ZnO nanoparticle reinforced PMMA matrix in temperature range 313-373 K. The results elucidated a phase transition from glassy to rubbery state at 344 K.

Direct electrochemistry and electrocatalysis of glucose oxidase immobilized on reduced graphene oxide and silver nanoparticles nanocomposite modified electrode.

Science.gov (United States)

Palanisamy, Selvakumar; Karuppiah, Chelladurai; Chen, Shen-Ming

2014-02-01

The direct electrochemistry of glucose oxidase (GOx) was successfully realized on electrochemically reduced graphene oxide and silver nanoparticles (RGO/Ag) nanocomposite modified electrode. The fabricated nanocomposite was characterized by field emission scanning electron microscope and energy dispersive spectroscopy. The GOx immobilized nanocomposite modified electrode showed a pair of well-defined redox peaks with a formal potential (E°) of -0.422 V, indicating that the bioactivity of GOx was retained. The heterogeneous electron transfer rate constant (Ks) of GOx at the nanocomposite was calculated to be 5.27 s(-1), revealing a fast direct electron transfer of GOx. The GOx immobilized RGO/Ag nanocomposite electrode exhibited a good electrocatalytic activity toward glucose over a linear concentration range from 0.5 to 12.5 mM with a detection limit of 0.16 mM. Besides, the fabricated biosensor showed an acceptable sensitivity and selectivity for glucose. Copyright © 2013 Elsevier B.V. All rights reserved.

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 ...

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.

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.

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.

Characterization of polyurethane/organophilic montmorillonite nanocomposites by low field NMR

International Nuclear Information System (INIS)

Silva, Marcos Anacleto da; Tavares, Maria I.B.; Nascimento, Suelen A.M.; Rodrigues, Elton J. da R

2012-01-01

Polyurethanes are important and versatile materials, mainly due to some of their properties, such as high resistance to abrasion and tearing, excellent absorption of mechanical shocks and good flexibility and elasticity. However, they have some drawbacks as well, such as low thermal stability and barrier properties. To overcome these disadvantages, various studies have been conducted involving organophilic polyurethane/montmorillonite nanocomposites. The investigation of the structure of polyurethane/clay nanocomposites has mainly been done by X-ray diffraction (XRD) and transmission electron microscopy (TEM). In this work, PU/clay nanocomposite films obtained by solution intercalation were studied. The nanocomposites were characterized by XRD and low-field nuclear magnetic resonance (LF-NMR). The LF-NMR measurements, with determination of the spin-lattice relaxation time of the hydrogen nucleus, supplied important information about the molecular dynamics of these nanocomposites. The X-ray diffraction measurements validated the results found by NMR. The thermal stability of the material was also determined by thermogravimetric analysis (TGA) under an inert atmosphere. A slight improvement in this stability was observed in the nanocomposite in comparison with polyurethane (author)

Syntheses and characterization of novel P/Si polysilsesquioxanes/epoxy nanocomposites

International Nuclear Information System (INIS)

Chiu Yiechan; Liu Fangyi; Ma, C.-C.M.; Chou, I.-C.; Riang Linawati; Chiang, C.-L.; Yang, J.-C.

2008-01-01

Phosphorus-containing polysilsesquioxane (PSSQ) was introduced into diglycidyl ether of bisphenol A epoxy (DGEBA) to generate a novel P/Si PSSQ nanocomposite. A series of nanocomposites was fabricated by changing the content of the 2-(diphenylphosphino)ethyltriethoxysilane (DPPETES) monomer or P/Si PSSQ cured with DGEBA epoxy and modified epoxy. The structure, thermal properties and flame-retardancy of the P/Si PSSQ nanocomposites were characterized by FT-IR, solid-state 29 Si NMR, thermogravimetric analysis (TGA) and limited oxygen index (LOI) instruments. The nano-sizes of the particles in P/Si PSSQ were approximately 30-50 nm, and the polarity of nanocomposites might generate the nanophase-separated structure from transmission electron microscopy (TEM). The urethane-like side group of the modified epoxy and the fabrication of oligomers in the curing reaction affected the T d5 values of nanocomposites. TGA and LOI results indicated that the char yield (29 wt%) increased and the nanocomposites were not very flammable (LOI = 30). The hybrid materials also exhibited high thermal stability, good flame-retardance and a lack of phase separation

Electronic resource management practical perspectives in a new technical services model

CERN Document Server

Elguindi, Anne

2012-01-01

A significant shift is taking place in libraries, with the purchase of e-resources accounting for the bulk of materials spending. Electronic Resource Management makes the case that technical services workflows need to make a corresponding shift toward e-centric models and highlights the increasing variety of e-formats that are forcing new developments in the field.Six chapters cover key topics, including: technical services models, both past and emerging; staffing and workflow in electronic resource management; implementation and transformation of electronic resource management systems; the ro

Selective Sensing of Methanol by Poly( m-aminophenol)/Copper Nanocomposite

Science.gov (United States)

Bhuyan, Madhusmita; Samanta, Siddhartha; Kar, Pradip

2018-03-01

The nanocomposite film of conducting poly( m-aminophenol) with copper nanoparticles (PmAP/Cu) prepared by a single-step process has been demonstrated as the sensor material for selective detection of methanol vapor. Different techniques like Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, X-ray diffraction spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to evaluate the interfacial interactions between PmAP and Cu nanoparticles within their conducting nanocomposites. The induced doping interaction through fluctuating electrostatic charge transfer between free -OH groups of the PmAP and Cu nanoparticles was confirmed from the spectral characterizations. About 3 wt% of Cu nanoparticles having average size of around 30-50 nm confirmed by the SEM and TEM analysis, was optimized inside the PmAP matrix in terms of better dispersion as well as achieving the highest conductivity (1.05 × 10-6 S/cm). The sensing performances, viz., % response, response time, recovery time, selectivity and reproducibility of the nanocomposites were studied towards methanol vapor at different concentrations. The mechanism of selective methanol vapor sensing by PmAP/Cu nanocomposite film has been explained on the basis of selective dipole interaction characterized by zeta potential measurement.

Structural and XPS studies of PSi/TiO2 nanocomposites prepared by ALD and Ag-assisted chemical etching

International Nuclear Information System (INIS)

Iatsunskyi, Igor; Kempiński, Mateusz; Nowaczyk, Grzegorz; Jancelewicz, Mariusz; Pavlenko, Mykola; Załęski, Karol; Jurga, Stefan

2015-01-01

Highlights: • Porous silicon/TiO 2 nanocomposites have been investigated. • Morphology and chemical composition of PSi/TiO 2 nanocomposites were established. • Valence-band XPS maximums for PSi/TiO 2 nanocomposites were found and analyzed. - Abstract: PSi/TiO 2 nanocomposites fabricated by atomic layer deposition (ALD) and metal-assisted chemical etching (MACE) were investigated. The morphology and phase structure of PSi/TiO 2 nanocomposites were studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM) with an energy dispersive X-ray spectroscopy (EDX) and Raman spectroscopy. The mean size of TiO 2 nanocrystals was determined by TEM and Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical elemental composition by observing the behavior of the Ti 2p, O 1s and Si 2p lines. TEM, Raman spectroscopy and XPS binding energy analysis confirmed the formation of TiO 2 anatase phase inside the PSi matrix. The XPS valence band analysis was performed in order to investigate the modification of PSi/TiO 2 nanocomposites electronic structure. Surface defects states of Ti 3+ at PSi/TiO 2 nanocomposites were identified by analyzing of XPS valence band spectra

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.

Utilization of electronic information resources by academic staff at ...

African Journals Online (AJOL)

The study investigated the utilization of Electronic Information resources by the academic staff of Makerere University in Uganda. It examined the academic staff awareness of the resources available, the types of resources provided by the Makerere University Library, the factors affecting resource utilization. The study was ...

Highly Active PdNi/RGO/Polyoxometalate Nanocomposite Electrocatalyst for Alcohol Oxidation.

Science.gov (United States)

Hu, Jing; Wu, Xiaofeng; Zhang, Qingfan; Gao, Mingyan; Qiu, Haifang; Huang, Keke; Feng, Shouhua; Wang, Tingting; Yang, Ying; Liu, Zhelin; Zhao, Bo

2018-02-27

A PdNi/RGO/polyoxometalate nanocomposite has been successfully synthesized by a simple wet-chemical method. Characterizations such as transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction analysis, and X-ray photoelectron spectroscopy are employed to verify the morphology, structure, and elemental composition of the as-prepared nanocomposite. Inspired by the fast-developing fuel cells, the electrochemical catalytic performance of the nanocomposite toward methanol and ethanol oxidation in alkaline media is further tested. Notably, the nanocomposite exhibits excellent catalytic activity and long-term stability toward alcohol electrooxidation compared with the PdNi/RGO and commercial Pd/C catalyst. Furthermore, the electrochemical results reveal that the prepared nanocomposite is attractive as a promising electrocatalyst for direct alcohol fuel cells, in which the phosphotungstic acid plays a crucial role in enhancing the electrocatalytic activities of the catalyst.

Facile charge transport in FeN x /Mo₂N/CNT nanocomposites for ...

Indian Academy of Sciences (India)

The nanocomposites were characterized using powder XRD, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), ElectronDiffraction, ThermogravimetricAnalysis and FTIRSpectroscopy. The electrochemical investigations suggest that the electrocatalytic activity of the composite increases with ...

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

Electronic Resources Management Project Presentation 2012

KAUST Repository

Ramli, Rindra M.

2012-01-01

This presentation describes the electronic resources management project undertaken by the KAUST library. The objectives of this project is to migrate information from MS Sharepoint to Millennium ERM module. One of the advantages of this migration

Preparation of ZnO/Ag nanocomposite and coating on polymers for anti-infection biomaterial application.

Science.gov (United States)

Sadeghi, Babak

2014-01-24

ZnO/Ag nanocomposites coated with polyvinyl chloride (PVC) were prepared by chemical reduction method, for anti-infection biomaterial application. There is a growing interest in attempts in using biomolecular as the templates to grow inorganic nanocomposites in controlled morphology and structure. By optimizing the experiment conditions, we successfully fabricated high yield of ZnO/Ag nanocomposite with full coverage of high-density polyvinyl chloride (PVC) coating. More importantly, ZnO/Ag nanocomposites were shown to significantly inhibit the growth of Staphylococcus aureus in solution. It was further shown that ZnO/Ag nanocomposites induced thiol depletion that caused death of S. aureus. The coatings were fully characterized using techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Most importantly, compared to uncoated metals, the coatings on PVC promoted healthy antibacterial activity. Importantly, compared to ZnO-Ag -uncoated PVC, the ZnO/Ag nanocomposites coated was approximately triplet more effective in preventing bacteria attachment. The result of Thermal Gravimetric Analysis (TGA) indicates that, the ZnO/Ag nanocomposites are chemically stable in the temperature range from 50 to 900°C. This result, for the first time, demonstrates the potential of using ZnO/Ag nanocomposites as a coating material for numerous anti-bacterial applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Luminescent, magnetic and optical properties of ZnO-ZnS nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Raleaooa, Pule V. [Department of Physics, University of the Free State, ZA 9300 Bloemfontein (South Africa); Department of Chemistry, University of the Free State, ZA 9300 (South Africa); Roodt, Andreas [Department of Chemistry, University of the Free State, ZA 9300 (South Africa); Mhlongo, Gugu G.; Motaung, David E. [DST/CSIR Nanotechnology Innovation Center, National Center for Nano-Structured Materials, Council for Scientific and Industrial Research, P.O. Box 395, ZA 0001 Pretoria (South Africa); Kroon, Robin E. [Department of Physics, University of the Free State, ZA 9300 Bloemfontein (South Africa); Ntwaeaborwa, Odireleng M., E-mail: ntwaeab@gmail.com [School of Physics, University of the Witwatersrand, Private Bag 3, Wits, ZA 2050 (South Africa)

2017-02-15

The structure, particle morphology, optical and magnetic properties of ZnO, ZnS and ZnO-ZnS nanoparticles prepared by the sol-gel method are reported. ZnO and ZnS were combined at room temperature by an ex situ synthetic route to prepare ZnO-ZnS nanocomposites. The nanocomposites exhibited particle morphology different from that of ZnO and ZnS nanoparticles. The ZnO and ZnS nanoparticles exhibited quantum confinement as inferred from the widening of their respective bandgap energies. The electron paramagnetic resonance data provided evidence for the existence of magnetic clusters near the surface, electron to nuclei interactions and defect states. The ZnO-ZnS nanocomposites exhibited tunable emission that was dependent on the ratio of ZnO to ZnS. These composites were evaluated for application in different types of light emitting devices.

Development of microbial resistant Carbopol nanocomposite hydrogels via a green process

CSIR Research Space (South Africa)

Varaprasad, K

2014-01-01

Full Text Available transform infrared (FTIR) spectroscopy, thermo-gravimetric analysis (TGA), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). The pure and inorganic nanocomposite hydrogels developed were tested...

Synthesis of TiO(2)-PMMA nanocomposite: using methacrylic acid as a coupling agent.

Science.gov (United States)

Khaled, S M; Sui, Ruohong; Charpentier, Paul A; Rizkalla, Amin S

2007-03-27

Inorganic-polymer nanocomposites are of significant interest for emerging materials due to their improved properties and unique combination of properties. Methacrylic acid (MA), a functionalization agent that can chemically link TiO2 nanomaterials (n-TiO2) and polymer matrix, was used to modify the surface of n-TiO2 using a Ti-carboxylic coordination bond. Then, the double bond in MA was copolymerized with methyl methacrylate (MMA) to form a n-TiO2-PMMA nanocomposite. The resulting n-TiO2-PMMA nanocomposite materials were characterized by using thermal analysis, electron microscopy, and elemental analysis. The dynamic mechanical properties (Young's and shear modulus) were measured using an ultrasonic pulse technique. The electron microscopy results showed a good distribution of the nanofillers in the polymer matrix. The glass transition temperature, thermal degradation temperature, and dynamic elastic moduli of the nanocomposites were shown to increase with an increase in the weight percentage of nanofibers in the composite. The resulting nanocomposites exhibited improved elastic properties and have potential application in dental composites and bone cements.

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.

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.

Fabrication of antimicrobial bacterial cellulose–Ag/AgCl nanocomposite using bacteria as versatile biofactory

International Nuclear Information System (INIS)

Liu Chuang; Yang Dong; Wang Yuangui; Shi Jiafu; Jiang Zhongyi

2012-01-01

In nature, a number of nanocomposites are formed through biomineralization-relevant processes under mild conditions. In the present study, a total “biologic” route to fabricate nanocomposite is reported. Non-pathogenic bacteria, Gluconacetobacter xylinum, was utilized as a versatile biofactory, which produced biopolymer bacterial cellulose (BC) and induced the formation of Ag/AgCl nanoparticles, yielding BC–Ag/AgCl nanocomposite. Scanning electron microscopy revealed that nanoparticles with average size of 17.4 nm were randomly embedded into the BC network; transmission electron microscopy and X-ray diffraction confirmed that the nanoparticles were mixtures of face-centered cubic silver and silver chloride nanoparticles. Moreover, the content of silver in the BC nanocomposite is around 0.05 wt%, determined by atomic absorption spectrometry and X-ray photoelectron spectroscopy analysis. The entire process of nanocomposite fabrication was conducted at ambient environment without utilizing toxic agents or producing hazardous products, which is not only environmentally friendly but also with less chances to generate harmful products to human bodies as biomedical materials. The resultant nanocomposite displayed the desirable activity in inhibiting bacterial growth of both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli microorganisms on agar plate and in liquid culture, indicating the potential of the material as antimicrobial wound dressing materials. This work demonstrated the feasibility of using microorganism to fabricate nanocomposite, especially for biomedical materials.

Fabrication of antimicrobial bacterial cellulose-Ag/AgCl nanocomposite using bacteria as versatile biofactory

Energy Technology Data Exchange (ETDEWEB)

Liu Chuang [Tianjin University, Key Laboratory for Green Technology, School of Chemical Engineering and Technology (China); Yang Dong; Wang Yuangui [Tianjin University, Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of Ministry of Education, School of Chemical Engineering and Technology (China); Shi Jiafu; Jiang Zhongyi, E-mail: zhyjiang@tju.edu.cn [Tianjin University, Key Laboratory for Green Technology, School of Chemical Engineering and Technology (China)

2012-08-15

In nature, a number of nanocomposites are formed through biomineralization-relevant processes under mild conditions. In the present study, a total 'biologic' route to fabricate nanocomposite is reported. Non-pathogenic bacteria, Gluconacetobacter xylinum, was utilized as a versatile biofactory, which produced biopolymer bacterial cellulose (BC) and induced the formation of Ag/AgCl nanoparticles, yielding BC-Ag/AgCl nanocomposite. Scanning electron microscopy revealed that nanoparticles with average size of 17.4 nm were randomly embedded into the BC network; transmission electron microscopy and X-ray diffraction confirmed that the nanoparticles were mixtures of face-centered cubic silver and silver chloride nanoparticles. Moreover, the content of silver in the BC nanocomposite is around 0.05 wt%, determined by atomic absorption spectrometry and X-ray photoelectron spectroscopy analysis. The entire process of nanocomposite fabrication was conducted at ambient environment without utilizing toxic agents or producing hazardous products, which is not only environmentally friendly but also with less chances to generate harmful products to human bodies as biomedical materials. The resultant nanocomposite displayed the desirable activity in inhibiting bacterial growth of both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli microorganisms on agar plate and in liquid culture, indicating the potential of the material as antimicrobial wound dressing materials. This work demonstrated the feasibility of using microorganism to fabricate nanocomposite, especially for biomedical materials.

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.

Practical guide to electronic resources in the humanities

CERN Document Server

Dubnjakovic, Ana

2010-01-01

From full-text article databases to digitized collections of primary source materials, newly emerging electronic resources have radically impacted how research in the humanities is conducted and discovered. This book, covering high-quality, up-to-date electronic resources for the humanities, is an easy-to-use annotated guide for the librarian, student, and scholar alike. It covers online databases, indexes, archives, and many other critical tools in key humanities disciplines including philosophy, religion, languages and literature, and performing and visual arts. Succinct overviews of key eme

Novel Electrochemical Synthesis of Polypyrrole/Ag Nanocomposite and Its Electrocatalytic Performance towards Hydrogen Peroxide Reduction

OpenAIRE

Ruma Gupta; Kavitha Jayachandran; J. S. Gamare; B. Rajeshwari; Santosh K. Gupta; J. V. Kamat

2015-01-01

A simple electrochemical method of synthesis of polypyrrole/silver (PPy/Ag) nanocomposite is presented. The method is based on potentiodynamic polymerization of pyrrole followed by electrodeposition of silver employing a single potentiostatic pulse. The synthesized PPy film has embedded Ag nanocubes. The morphology and structure of the resulting nanocomposite were characterized by field emission scanning electron microscopy and X-ray diffraction. Electron paramagnetic resonance studies showed...

Halloysite and chitosan oligosaccharide nanocomposite for wound healing.

Science.gov (United States)

Sandri, Giuseppina; Aguzzi, Carola; Rossi, Silvia; Bonferoni, Maria Cristina; Bruni, Giovanna; Boselli, Cinzia; Cornaglia, Antonia Icaro; Riva, Federica; Viseras, Cesar; Caramella, Carla; Ferrari, Franca

2017-07-15

Halloysite is a natural nanotubular clay mineral (HNTs, Halloysite Nano Tubes) chemically identical to kaolinite and, due to its good biocompatibility, is an attractive nanomaterial for a vast range of biological applications. Chitosan oligosaccharides are homo- or heterooligomers of N-acetylglucosamine and D-glucosamine, that accelerate wound healing by enhancing the functions of inflammatory and repairing cells. The aim of the work was the development of a nanocomposite based on HNTs and chitosan oligosaccharides, to be used as pour powder to enhance healing in the treatment of chronic wounds. A 1:0.05 wt ratio HTNs/chitosan oligosaccharide nanocomposite was obtained by simply stirring the HTNs powder in a 1% w/w aqueous chitosan oligosaccharide solution and was formed by spontaneous ionic interaction resulting in 98.6% w/w HTNs and 1.4% w/w chitosan oligosaccharide composition. Advanced electron microscopy techniques were considered to confirm the structure of the hybrid nanotubes. Both HTNs and HTNs/chitosan oligosaccharide nanocomposite showed good in vitro biocompatibility with normal human dermal fibroblasts up to 300μg/ml concentration and enhanced in vitro fibroblast motility, promoting both proliferation and migration. The HTNs/chitosan oligosaccharide nanocomposite and the two components separately were tested for healing capacity in a murine (rat) model. HTNs/chitosan oligosaccharide allowed better skin reepithelization and reorganization than HNTs or chitosan oligosaccharide separately. The results suggest to develop the nanocomposite as a medical device for wound healing. The present work is focused on the development of halloysite and chitosan oligosaccharide nanocomposite for wound healing. It considers a therapeutic option for difficult to heal skin lesions and burns. The significance of the research considers two fundamental aspects: the first one is related to the development of a self-assembled nanocomposite, formed by spontaneous ionic

Interactions between halloysite nanotubes and 2,5-bis(2-benzoxazolyl) thiophene and their effects on reinforcement of polypropylene/halloysite nanocomposites

International Nuclear Information System (INIS)

Liu Mingxian; Guo Baochun; Zou Quanliang; Du Mingliang; Jia Demin

2008-01-01

Many types of clay tend to absorb organics via electron transferring interactions between the clay and the organics. This may be utilized to design clay incorporated polymer composites with better interfacial properties. In the present paper, 2,5-bis(2-benzoxazolyl) thiophene (BBT), capable of donating electrons, is selected as the interfacial modifier for polypropylene (PP)/halloysite nanotube (HNTs) composites. The electron transfer between HNTs and BBT are confirmed. The mechanical properties and the unique morphology of the nanocomposites are examined. Formation of fibrils of BBT in the presence of HNTs is found in the nanocomposites. The chemical composition of the fibrils in the nanocomposites is found to be composed of largely BBT and a small amount of HNTs. The formation mechanism of BBT fibrils are elucidated to be the strong interactions between BBT and HNTs under melt shearing. The formation of the BBT fibrils leads to much higher crystallinity compared with previously reported PP nanocomposites. The nanocomposites with BBT show substantially increased tensile and flexural properties, which are attributed to the enhanced crystallinity of the nanocomposites

Interactions between halloysite nanotubes and 2,5-bis(2-benzoxazolyl) thiophene and their effects on reinforcement of polypropylene/halloysite nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Liu Mingxian; Guo Baochun; Zou Quanliang; Du Mingliang; Jia Demin [Department of Polymer Materials and Engineering, South China University of Technology, Guangzhou 510640 (China)], E-mail: psbcguo@scut.edu.cn

2008-05-21

Many types of clay tend to absorb organics via electron transferring interactions between the clay and the organics. This may be utilized to design clay incorporated polymer composites with better interfacial properties. In the present paper, 2,5-bis(2-benzoxazolyl) thiophene (BBT), capable of donating electrons, is selected as the interfacial modifier for polypropylene (PP)/halloysite nanotube (HNTs) composites. The electron transfer between HNTs and BBT are confirmed. The mechanical properties and the unique morphology of the nanocomposites are examined. Formation of fibrils of BBT in the presence of HNTs is found in the nanocomposites. The chemical composition of the fibrils in the nanocomposites is found to be composed of largely BBT and a small amount of HNTs. The formation mechanism of BBT fibrils are elucidated to be the strong interactions between BBT and HNTs under melt shearing. The formation of the BBT fibrils leads to much higher crystallinity compared with previously reported PP nanocomposites. The nanocomposites with BBT show substantially increased tensile and flexural properties, which are attributed to the enhanced crystallinity of the nanocomposites.

Simple One-Step Method to Synthesize Polypyrrole-Indigo Carmine-Silver Nanocomposite

OpenAIRE

Loguercio, Lara Fernandes; Demingos, Pedro; Manica, Luiza de Mattos; Griep, Jordana Borges; Santos, Marcos José Leite; Ferreira, Jacqueline

2016-01-01

A nanocomposite of indigo carmine doped polypyrrole/silver nanoparticles was obtained by a one-step electrochemical process. The nanocomposite was characterized by scanning electron microscopy, infrared spectroscopy, ultraviolet-visible-near infrared spectroscopy, and cyclic voltammetry. The simple one-step process allowed the growth of silver nanoparticles during the polymerization of polypyrrole, resulting in films with electrochromic behavior and improved electroactivity. In addition, poly...

Temperature dependent magnetic behavior of α-Fe2O3/GO nanocomposites

Science.gov (United States)

Mishra, Amodini; Moahnty, T.; Kuanr, B. K.

2018-04-01

Here, α-Fe2O3/GO nanocomposites were successfully synthesized by using the co-precipitation method. The phase formation of α-Fe2O3 nanoparticles was confirmed by using X-ray diffraction (XRD) study. The study of surface morphology of α-Fe2O3/GO nanocomposites was performed by using field emission scanning electron microscopy (FESEM) technique. Magnetic property measurement and determination of various magnetic parameters of α-Fe2O3/GO nanocomposites was carried out by physical property measurement system (PPMS).

Novel CuCr_2O_4 embedded CuO nanocomposites for efficient photodegradation of organic dyes

International Nuclear Information System (INIS)

Mageshwari, K.; Sathyamoorthy, R.; Lee, Jeong Yong; Park, Jinsub

2015-01-01

Graphical abstract: - Highlights: • Novel CuO–CuCr_2O_4 nanocomposites synthesized by reflux condensation method. • Methyl orange and methylene blue dye degradation studied under UV light irradiation. • Nanocomposites characterized by XRD, FESEM, TEM, EDX, UV–vis DRS and PL. • CuCr_2O_4 loading effectively enhanced the catalytic activity of CuO. - Abstract: Novel photocatalyst based on CuO–CuCr_2O_4 nanocomposites was synthesized for different Cr"3"+ concentration by reflux condensation method, and their photocatalytic activity was evaluated by monitoring the photodegradation of methyl orange (MO) and methylene blue dyes (MB) under UV light irradiation. Phase evolution by X-ray diffraction showed monoclinic CuO and tetragonal CuCr_2O_4 as the components of the prepared nanocomposites. Morphological analysis by scanning electron microscope and transmission electron microscope revealed that the incorporation of Cr"3"+ in CuO lattice alters the morphology of CuO from microsphere to cluster shape. Photoluminescence spectra of CuO–CuCr_2O_4 nanocomposites exhibited reduced PL emissions compared to pure CuO, indicating the low recombination rate of photogenerated electrons and holes. As expected, the CuCr_2O_4 loaded CuO showed enhanced photocatalytic activity for MO and MB dyes, and the kinetic studies suggest that the degradation follows pseudo-first-order kinetics. The enhanced photocatalytic activity of CuO–CuCr_2O_4 nanocomposites can be attributed to the presence of CuCr_2O_4 as an electron acceptor, which improves the effective charge separation in CuO.

Utilisation of Electronic Information Resources By Lecturers in ...

African Journals Online (AJOL)

This study assesses the use of information resources, specifically, electronic databases by lecturers/teachers in Universities and Colleges of Education in South Western Nigeria. Information resources are central to teachers' education. It provides lecturers/teachers access to information that enhances research and ...

Improved photoluminescence property of CTAB assisted polyaniline-AlZnO nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Mitra, Mousumi; Banerjee, Dipali, E-mail: dipalibanerjeebesu@gmail.com [Department of Physics, Indian Institute of Engineering Science and Technology, Shibpur, Howrah (India); Kargupta, Kajari [Department of Chemical Engineering, Jadavpur University, Kolkata (India); Ganguly, Saibal [Chemical Engineering department, Universiti Teknology Petronas, Tronoh (Malaysia)

2015-06-24

Polyaniline-Al doped ZnO ((PANI-AlZnO:: 70:30) nanocomposite was prepared via in situ chemical oxidative polymerization, while the hexagonal powder of AlZnO was synthesized via sol-gel technique, using Hexadecyltrimethylammonium bromide (CTAB) as a capping agent. The prepared nanocomposite was characterized by High resolution transmission electron microscopy (HRTEM), EDAX, X-ray diffraction (XRD) and Fourier transforms infrared (FTIR) spectra. The optical property of the nanomaterials is examined by photoluminescence (PL) spectra analysis. The XRD pattern confirms the formation of Al doped ZnO as well as PANI. The HRTEM images of the composite showed the formation of hexagonal AlZnO embedded in polyaniline matrix. EDAX spectrum shows the compositional analysis of the nanocomposite. FTIR spectra confirm the formation of nanocomposite of PANI and hexagonal AlZnO. The PL intensity of the nanocomposite is improved as compared to pure AlZnO.

Nanowires of silver-polyaniline nanocomposite synthesized via in situ polymerization and its novel functionality as an antibacterial agent.

Science.gov (United States)

Tamboli, Mohaseen S; Kulkarni, Milind V; Patil, Rajendra H; Gade, Wasudev N; Navale, Shalaka C; Kale, Bharat B

2012-04-01

Silver-polyaniline (Ag-PANI) nanocomposite was synthesized by in situ polymerization method using ammonium persulfate (APS) as an oxidizing agent in the presence of dodecylbenzene sulfonic acid (DBSA) and silver nitrate (AgNO(3)). The as synthesized Ag-PANI nanocomposite was characterized by using different analytical techniques such as UV-visible (UV-vis) and Fourier transform Infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), thermo gravimetric analysis (TGA), X-ray diffraction (XRD), and transmission electron microscopy (TEM). UV-visible spectra of the synthesized nanocomposite showed a sharp peak at ~420 nm corresponding to the surface plasmon resonance (SPR) of the silver nanoparticles (AgNPs) embedded in the polymer matrix which is overlapped by the polaronic peak of polyaniline appearing at that wavelength. Nanowires of Ag-PANI nanocomposite with diameter 50-70 nm were observed in FE-SEM and TEM. TGA has indicated an enhanced thermal stability of nanocomposite as compared to that of pure polymer. The Ag-PANI nanocomposite has shown an antibacterial activity against model organisms, a gram positive Bacillus subtilis NCIM 6633 in Mueller-Hinton (MH) medium, which is hitherto unattempted. The Ag-PANI nanocomposite with monodispersed AgNPs is considered to have potential applications in sensors, catalysis, batteries and electronic devices. Copyright © 2011 Elsevier B.V. All rights reserved.

Polyaniline silver nanoparticle coffee waste extracted porous graphene oxide nanocomposite structures as novel electrode material for rechargeable batteries

Science.gov (United States)

Sundriyal, Poonam; Bhattacharya, Shantanu

2017-03-01

The exploration of new and advanced electrode materials are required in electronic and electrical devices for power storage applications. Also, there has been a continuous endeavour to formulate strategies for extraction of high performance electrode materials from naturally obtained waste products. In this work, we have developed an in situ hybrid nanocomposite from coffee waste extracted porous graphene oxide (CEPG), polyaniline (PANI) and silver nanoparticles (Ag) and have found this novel composite to serve as an efficient electrode material for batteries. The successful interaction among the three phases of the nano-composite i.e. CEPG-PANI-Ag have been thoroughly understood through RAMAN, Fourier transform infrared and x-ray diffraction spectroscopy, morphological studies through field emission scanning electron microscope and transmission electron microscope. Thermo-gravimetric analysis of the nano-composite demonstrates higher thermal stability up-to a temperature of 495 °C. Further BET studies through nitrogen adsorption-desorption isotherms confirm the presence of micro/meso and macro-pores in the nanocomposite sample. The cyclic-voltammetry (CV) analysis performed on CEPG-PANI-Ag nanocomposite exhibits a purely faradic behaviour using nickel foam as a current collector thus suggests the prepared nanocomposite as a battery electrode material. The nanocomposite reports a maximum specific capacity of 1428 C g-1 and excellent cyclic stability up-to 5000 cycles.

SYNTHESIS AND STUDY OF CORROSION PERFORMANCE OF EPOXY COATING CONTAINING MULTI-WALLED CARBON NANOTUBE/ POLY ORTHO AMINOPHENOL NANOCOMPOSITE

Directory of Open Access Journals (Sweden)

N. Bahrami Panah

2016-03-01

Full Text Available The epoxy coatings containing multi-walled carbon nanotube/ poly ortho aminophenol nanocomposite were prepared and used as anticorrosive coatings. The nanocomposites with different contents of carbon nanotube were synthesized in a solution of sodium dodecyl sulfate and ammonium peroxy disulfate as a surfactant and an oxidant, respectively. The morphology and structural properties were confirmed by Fourier transform infrared spectroscopy and scanning electron microscopy methods. The mean size of nanocomposite particles was 20-35 nm determined by scanning electron microscopy. The epoxy coatings containing the nanocomposites were applied over mild steel panels and their corrosion performance was investigated using electrochemical impedance spectroscopy and potentiodynamic polarization measurements in a 3.5 % sodium chloride solution. The results showed that epoxy coatings consisting of nanocomposite with 1 wt.% multi-walled carbon nanotube exhibited higher anticorrosive properties than other prepared coatings of different carbon nanotube contents, which could be due to the strong interaction between the mild steel surface and the conjugated nanocomposite.

High-Resolution of Electron Microscopy of Montmorillonite and Montmorillonite/Epoxy Nanocomposites

National Research Council Canada - National Science Library

Drummy, Lawrence F; Farmer, Karen; Tan, Ashley; Farmer, B. L; Vaia, Richard A; Koerner, Hilmar

2005-01-01

...), a material of current interest for use in polymer nanocomposites, was characterized. Using both imaging theory and experiment, the procedures needed to generate lattice images from MMT were established...

Ag nanocrystals anchored CeO2/graphene nanocomposite for enhanced supercapacitor applications

International Nuclear Information System (INIS)

Vanitha, M.; Keerthi; Cao, P.; Balasubramanian, N.

2015-01-01

Highlights: • Quasi spherical Ag and CeO 2 nanoparticles were decorated on rGO matrix. • The Ag/CeO 2 /rGO nanocomposite exhibits specific capacitance of 710 F g −1 . • Ag plays an imperative role in improving the electrochemical performance. - Abstract: A novel ternary Ag decorated CeO 2 /reduced graphene oxide (rGO) nanocomposite was synthesized by a facile hydrothermal method with polyvinylpyrrolidone (PVP) as surface directing agent and was designed as an electrode material for supercapacitors application. The structure and morphology of the nanocomposites were analyzed by X-ray diffraction analysis (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The synergistic effect between the CeO 2 nanoparticles wrapped rGO matrix with Ag nanoparticles gives rise to a nanostructure, empowering the material with enhanced electrochemical performance. The electrochemical characterization was performed using cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopic studies in 3 M KOH aqueous electrolyte. The nanocomposite electrode materials possess a high specific capacitance of 710.42 F g −1 at an applied current density of 0.2 A g −1 , which was nearly two fold higher than CeO 2 /rGO nanocomposite. This work endows a new route for building Ag/CeO 2 /rGO ternary nanocomposite which will have some impact on the exploitation of novel ternary electrode materials for supercapacitor applications

Nanocomposites of thermoplastic rubber with organically modified nanoclay

International Nuclear Information System (INIS)

Costa, Marcia P.M. da; Garcia, Tania M.; Guimaraes, Maria Jose O.C.; Garcia, Maria Elisabeth F.; Mendes, Luis Claudio

2009-01-01

Polymeric nanocomposites are a new class of composites that contain small quantities of nanoparticle, with one of its dimensions in the nano-scale. In this work nanocomposites based on SBS and an organically modified clay were prepared The nanocomposites were processed in a Haake mixer, at 180 deg C, 70 rpm for 7 minutes, using nanoclay concentrations of 1%, 3.5% and 6%. The samples were characterized by thermogravimetry (TG), X-Ray Diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). The results showed that the addition of nanoclay didn't affect significantly the thermal stability of SBS. In the analysis of SEM was observed that there was not a complete nanoclay delamination in the copolymer matrix due to the presence of some tactoids dispersed in the SBS matrix. (author)

Thermoset nanocomposites from waterborne bio-based epoxy resin and cellulose nanowhiskers.

Science.gov (United States)

Wu, Guo-min; Liu, Di; Liu, Gui-feng; Chen, Jian; Huo, Shu-ping; Kong, Zhen-wu

2015-01-01

Thermoset nanocomposites were prepared from a waterborne terpene-maleic ester type epoxy resin (WTME) and cellulose nanowhiskers (CNWs). The curing behaviors of WTME/CNWs nanocomposites were measured with rotational rheometer. The results show that the storage modulus (G') of WTME/CNWs nanocomposites increased with the increase of CNWs content. Observations by scanning electron microscopy (SEM) demonstrate that the incorporation of CNWs in WTME matrix caused microphase separation and destroyed the compactness of the matrix. This effect leads to the glass transition temperatures (Tg) of WTME/CNWs nanocomposites slightly decrease with the increase of CNWs content, which were confirmed by both DSC and DMA tests. The mechanical properties of WTME/CNWs nanocomposites were investigated by tensile testing. The Yong's modulus (E) and tensile strength (σb) of the nanocomposites were significantly reinforced by the addition of CNWs. These results indicate that CNWs exhibit excellent reinforcement effect on WTME matrix, due to the formation and increase of interfacial interaction by hydrogen bonds between CNWs nano-filler and the WTME matrix. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

Discipline, availability of electronic resources and the use of Finnish National Electronic Library - FinELib

Directory of Open Access Journals (Sweden)

Sanna Torma

2004-01-01

Full Text Available This study elaborated relations between digital library use by university faculty, users' discipline and the availability of key resources in the Finnish National Electronic Library (FinELib, Finnish national digital library, by using nationwide representative survey data. The results show that the perceived availability of key electronic resources by researchers in FinELib was a stronger predictor of the frequency and purpose of use of its services than users' discipline. Regardless of discipline a good perceived provision of central resources led to a more frequent use of FinELib. The satisfaction with the services did not vary with the discipline, but with the perceived availability of resources.

Synthesis of polymer/inorganic nanocomposite films using highly porous inorganic scaffolds.

Science.gov (United States)

Zhang, Huanjun; Popp, Matthias; Hartwig, Andreas; Mädler, Lutz

2012-04-07

Polymeric/inorganic nanocomposite films have been fabricated through a combination of flame-spray-pyrolysis (FSP) made inorganic scaffold and surface initiated polymerization of cyanoacrylate. The highly porous structure of pristine SnO(2) films allows the uptake of cyanoacrylate and the polymerization is surface initiated by the water adsorbed onto the SnO(2) surface. Scanning electron microscopy study reveals a nonlinear increase in the composite particle size and the film thickness with polymerization time. The structural change is rather homogeneous throughout the whole layer. The composite is formed mainly by an increase of the particle size and not by just filling the existing pores. High-resolution transmission electron microscopy imaging shows SnO(2) nanoparticles embedded in the polymeric matrix, constituting the nanocomposite material. Thermogravimetric analysis indicates that the porosity of the nanocomposite films decreases from 98% to 75%, resulting in a significant enhancement of the hardness of the films. DC conductivity measurements conducted in situ on the nanocomposite layer suggest a gradual increase in the layer resistance, pointing to a loss of connectivity between the SnO(2) primary particles as the polymerization proceeds. This journal is © The Royal Society of Chemistry 2012

The Role of the Acquisitions Librarian in Electronic Resources Management

Science.gov (United States)

Pomerantz, Sarah B.

2010-01-01

With the ongoing shift to electronic formats for library resources, acquisitions librarians, like the rest of the profession, must adapt to the rapidly changing landscape of electronic resources by keeping up with trends and mastering new skills related to digital publishing, technology, and licensing. The author sought to know what roles…

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.

Gas-phase synthesis of magnetic metal/polymer nanocomposites

Science.gov (United States)

Starsich, Fabian H. L.; Hirt, Ann M.; Stark, Wendelin J.; Grass, Robert N.

2014-12-01

Highly magnetic metal Co nanoparticles were produced via reducing flame spray pyrolysis, and directly coated with an epoxy polymer in flight. The polymer content in the samples varied between 14 and 56 wt% of nominal content. A homogenous dispersion of Co nanoparticles in the resulting nanocomposites was visualized by electron microscopy. The size and crystallinity of the metallic fillers was not affected by the polymer, as shown by XRD and magnetic hysteresis measurements. The good control of the polymer content in the product nanocomposite was shown by elemental analysis. Further, the successful polymerization in the gas phase was demonstrated by electron microscopy and size measurements. The presented effective, dry and scalable one-step synthesis method for highly magnetic metal nanoparticle/polymer composites presented here may drastically decrease production costs and increase industrial yields.

Preparation of ultra-light magnetic nanocomposites using highly concentrated emulsions

Energy Technology Data Exchange (ETDEWEB)

Ghosh, Goutam; Vilchez, Alejandro; Esquena, Jordi; Solans, Conxita [Instituto de Quimica Avanzada de Cataluna, Consejo Superior de Investigaciones Cientificas (IQAC-CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain); Rodriguez-Abreu, Carlos, E-mail: carlos.rodriguez@inl.int [Instituto de Quimica Avanzada de Cataluna, Consejo Superior de Investigaciones Cientificas (IQAC-CSIC), Jordi Girona 18-26, 08034 Barcelona (Spain); International Iberian Nanotechnology Laboratory (INL), Av. Mestre Jose Veiga, 4715-330 Braga (Portugal)

2011-10-17

Highlights: {yields} Polystyrene-divinylbenzene-iron oxide nanocomposites. {yields} Porous magnetic nanocomposites from highly concentrated emulsions. {yields} Ultralight materials with relatively high magnetic moment. - Abstract: Hybrid inorganic-organic ultra-light magnetic solid foams with iron oxide nanoparticles embedded in a divinylbenzene-polystyrene matrix were prepared using a highly concentrated emulsion polymerization method. Iron oxide nanoparticles with diameters of 3 and 10 nm were synthesized using two different methods. For comparison purposes, nanocomposites with magnetite nanoparticles dispersed in a non-porous polymeric matrix obtained by bulk polymerization were also investigated. Materials were characterized using several techniques such as dynamic light scattering (DLS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), small angle X-ray scattering (SAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and magnetization measurements. SEM and TEM images showed that solid foams are made of well-defined macro pores with nanoparticles embedded in the walls. The density of the solid foams was ca. 50-70 kg m{sup -3}, which is about 20 times lighter than the non-porous monoliths. The magnetic measurements show that both nanocomposites are superparamagnetic, and that there are differences regarding the interparticle interactions depending on matrix porosity. The synthesized materials may find applications in adsorbents, tissue reparation, enzyme supports, microreactors, or in water decontamination.

Preparation of ultra-light magnetic nanocomposites using highly concentrated emulsions

International Nuclear Information System (INIS)

Ghosh, Goutam; Vilchez, Alejandro; Esquena, Jordi; Solans, Conxita; Rodriguez-Abreu, Carlos

2011-01-01

Highlights: → Polystyrene-divinylbenzene-iron oxide nanocomposites. → Porous magnetic nanocomposites from highly concentrated emulsions. → Ultralight materials with relatively high magnetic moment. - Abstract: Hybrid inorganic-organic ultra-light magnetic solid foams with iron oxide nanoparticles embedded in a divinylbenzene-polystyrene matrix were prepared using a highly concentrated emulsion polymerization method. Iron oxide nanoparticles with diameters of 3 and 10 nm were synthesized using two different methods. For comparison purposes, nanocomposites with magnetite nanoparticles dispersed in a non-porous polymeric matrix obtained by bulk polymerization were also investigated. Materials were characterized using several techniques such as dynamic light scattering (DLS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), small angle X-ray scattering (SAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and magnetization measurements. SEM and TEM images showed that solid foams are made of well-defined macro pores with nanoparticles embedded in the walls. The density of the solid foams was ca. 50-70 kg m -3 , which is about 20 times lighter than the non-porous monoliths. The magnetic measurements show that both nanocomposites are superparamagnetic, and that there are differences regarding the interparticle interactions depending on matrix porosity. The synthesized materials may find applications in adsorbents, tissue reparation, enzyme supports, microreactors, or in water decontamination.

Organic-Inorganic Hydrophobic Nanocomposite Film with a Core-Shell Structure

Directory of Open Access Journals (Sweden)

Peng Liu

2016-12-01

Full Text Available A method to prepare novel organic-inorganic hydrophobic nanocomposite films was proposed by a site-specific polymerization process. The inorganic part, the core of the nanocomposite, is a ternary SiO2–Al2O3–TiO2 nanoparticles, which is grafted with methacryloxy propyl trimethoxyl silane (KH570, and wrapped by fluoride and siloxane polymers. The synthesized samples are characterized by transmission electron microscopy (TEM, Fourier transform infrared (FTIR spectrscopy, X-ray diffractometry (XRD, contact angle meter (CA, and scanning electron microscope (SEM. The results indicate that the novel organic-inorganic hydrophobic nanocomposite with a core-shell structure was synthesized successfully. XRD analysis reveals the nanocomposite film has an amorphous structure, and FTIR analysis indicates the nanoparticles react with a silane coupling agent (methacryloxy propyl trimethoxyl silane KH570. Interestingly, the morphology of the nanoparticle film is influenced by the composition of the core. Further, comparing with the film synthesized by silica nanoparticles, the film formed from SiO2–Al2O3–TiO2 nanoparticles has higher hydrophobic performance, i.e., the contact angle is greater than 101.7°. In addition, the TEM analysis reveals that the crystal structure of the particles can be changed at high temperatures.

Mechanical properties of multi-walled carbon nanotube/epoxy polysulfide nanocomposite

International Nuclear Information System (INIS)

Shirkavand Hadavand, Behzad; Mahdavi Javid, Kimya; Gharagozlou, Mehrnaz

2013-01-01

Highlights: ► Preparation of epoxy polysulfide nanocomposite. ► Multi-walled carbon nanotubes have been modified and dispersed in epoxy polysulfide matrix. ► Mechanical properties of MWNT/epoxy polysulfide have been studied. - Abstract: In this research, multi-walled carbon nanotubes (MWCNTs) were modified by acid functionalization (H 2 SO 4 :HNO 3 = 1:3 by volume) and then mechanical properties of reinforced epoxy polysulfide resin by the both pure and treated MWNTs have been evaluated. For achieving this goal, different weight percentages of pure and treated MWCNT (0.1–0.3 wt%) were dispersed in the epoxy polysulfide resin separately and then mixed with curing agent. Experimental results have shown significant difference between acid treated and untreated MWCNTs in mechanical properties of epoxy polysulfide nanocomposites. In nanocomposite with 0.1–0.3% acid treated MWCNTs we observed increase of Young’s modulus from 458 to 723 MPa, tensile strength from 5.29 to 8.83 MPa and fracture strain from 0.16% to 0.25%. For understanding the structure and morphology of nanocomposite, the dispersion states were studied using scanning electron microscopy (SEM) and field emission electron microscopy (FESEM). The results showed better dispersion of modified carbon nanotube than unmodified in polymeric matrix

Novel MnOOH–graphene nanocomposites: Preparation, characterization and electrochemical properties for supercapacitors

International Nuclear Information System (INIS)

Mei, Jun; Zhang, Long

2015-01-01

In this paper, we report a simple and controlled synthesis of novel MnOOH–graphene nanocomposites with a one-step facile hydrothermal method. It is template-free and easy to reproduce. Electrochemical properties are investigated in different media. The values of specific capacitance achieved are 112 F g −1 in 1 M Na 2 SO 4 and 165 F g −1 in 6 M KOH electrolyte, respectively. The assembly of multiple branched MnOOH and graphene flakes results in synergistic effects, forming new electron transfer channels to accelerate electron transfer and provide the pseudocapacitance to increase the overall capacitance. The novel composites have potential applications in the fields of supercapacitors, lithium battery and so on. - Graphical abstract: The MnOOH–graphene nanocomposites shows better specific capacitance with the values achieved 112 F g −1 in 1 M Na 2 SO 4 and 165 F g −1 in 6 M KOH electrolyte, respectively. - Highlights: • Novel MnOOH–graphene nanocomposites were prepared by a one-step hydrothermal method. • The assembly can form new electron transfer channels to accelerate electron transfer. • The capacitive and rate performances are enhanced in both neutral and alkaline medium

Analysis of Pedagogic Potential of Electronic Educational Resources with Elements of Autodidactics

Directory of Open Access Journals (Sweden)

Igor A.

2018-03-01

Full Text Available Introduction: in recent years didactic properties of electronic educational resources undergo considerable changes, nevertheless, the question of studying of such complete phenomenon as “an electronic educational resource with autodidactics elements” remains open, despite sufficient scientific base of researches of the terms making this concept. Article purpose – determination of essence of electronic educational resources with autodidactics elements. Materials and Methods: the main method of research was the theoretical analysis of the pedagogical and psychological literature on the problem under study. We used the theoretical (analysis, synthesis, comparison and generalization methods, the method of interpretation, pedagogical modeling, and empirical methods (observation, testing, conversation, interview, analysis of students’ performance, pedagogical experiment, peer review. Results: we detected the advantages of electronic educational resources in comparison with traditional ones. The concept of autodidactics as applied to the subject of research is considered. Properties of electronic educational resources with a linear and nonlinear principle of construction are studied.The influence of the principle of construction on the development of the learners’ qualities is shown. We formulated an integral definition of electronic educational resources with elements of autodidactics, namely, the variability, adaptivity and cyclicity of training. A model of the teaching-learning process with electronic educational resources is developed. Discussion and Conclusions: further development of a problem will allow to define whether electronic educational resources with autodidactics elements pedagogical potential for realization of educational and self-educational activity of teachers have, to modify technological procedures taking into account age features of students, their specialties and features of the organization of process of training of

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.

Preservation and conservation of electronic information resources of ...

African Journals Online (AJOL)

The major holdings of the broadcast libraries of the Nigerian Television Authority (NTA) are electronic information resources; therefore, providing safe places for general management of these resources have aroused interest in the industry in Nigeria for sometimes. The need to study the preservation and conservation of ...

Liquid phase mass production of air-stable black phosphorus/phospholipids nanocomposite with ultralow tunneling barrier

Science.gov (United States)

Zhang, Qiankun; Liu, Yinan; Lai, Jiawei; Qi, Shaomian; An, Chunhua; Lu, Yao; Duan, Xuexin; Pang, Wei; Zhang, Daihua; Sun, Dong; Chen, Jian-Hao; Liu, Jing

2018-04-01

Few-layer black phosphorus (FLBP), a recently discovered two-dimensional semiconductor, has attracted substantial attention in the scientific and technical communities due to its great potential in electronic and optoelectronic applications. However, reactivity of FLBP flakes with ambient species limits its direct applications. Among various methods to passivate FLBP in ambient environment, nanocomposites mixing FLBP flakes with stable matrix may be one of the most promising approaches for industry applications. Here, we report a simple one-step procedure to mass produce air-stable FLBP/phospholipids nanocomposite in liquid phase. The resultant nanocomposite is found to have ultralow tunneling barrier for charge carriers which can be described by an Efros-Shklovskii variable range hopping mechanism. Devices made from such mass-produced FLBP/phospholipids nanocomposite show highly stable electrical conductivity and opto-electrical response in ambient conditions, indicating its promising applications in both electronic and optoelectronic applications. This method could also be generalized to the mass production of nanocomposites consisting of other air-sensitive 2D materials, such as FeSe, NbSe2, WTe2, etc.

Carbon nanofiber/polyethylene nanocomposite: Processing behavior, microstructure and electrical properties

International Nuclear Information System (INIS)

Al-Saleh, Mohammed H.; Gelves, Genaro A.; Sundararaj, Uttandaraman

2013-01-01

Highlights: • Electrically conductive CNF/HDPE nanocomposite were prepared by melt compounding. • The effect of processing on the nanocomposites macro and micro structures was analyzed. • 1.4 vol% CNF were required to construct a conductive network within the HDPE matrix. • An EMI SE of 42 dB was reported for 15 vol% CNF/HDPE nanocomposite. • An empirical model was developed to estimate the EMI SE. - Abstract: Electrically conductive polymer nanocomposite of high density polyethylene (HDPE) filled with carbon nanofibers (CNFs) were prepared by melt compounding in a batch mixer. The nanocomposite processing behavior was studied by monitoring the mixing torque vs. time as function of filler content. Scanning electron microscopy and optical microscopy were used to investigate the nanocomposite dispersion of nanofiller and the adhesion between the nanofiller and polymer matrix. The electrical and electromagnetic interference (EMI) shielding behaviors of the nanocomposite were reported as function of nanofibers concentration, and an empirical correlation related the EMI SE to the nanocomposite’s electrical resistivity was developed. Good level of CNF dispersion was evident despite the poor adhesion exhibited between the nanofibers and the HDPE matrix. At 1.5 vol% CNF loading, the nanocomposite exhibited an electrical volume resistivity of 10 5 Ω·cm. EMI shielding effectiveness was found to increase with increase in nanofiller concentration. In the 0.1–1.5 GHz frequency range, 2 mm thick plate made of 5 vol% CNF/HDPE nanocomposite exhibits an EMI shielding effectiveness of 20 dB

Optical and Electrical Studies of Polyaniline/ZnO Nanocomposite

Directory of Open Access Journals (Sweden)

Manawwer Alam

2013-01-01

Full Text Available Polyaniline (Pani/ZnO nanocomposite with diameter 40–50 nm was successfully fabricated by coprecipitation method of ZnO via in situ polymerization of Pani. X-ray diffraction (XRD, high resolution transmission electron microscopy (HRTEM, fourier transformation infrared (FT-IR, UV-Vis absorption spectra, thermogravimetric analysis (TGA, and electrical properties were studied. HRTEM studies showed that the prepared ZnO nanoparticles were uniformly dispersed and highly stabilized throughout the polymer chain and formed uniform metal oxide-conducting polymer nanocomposite material. UV-Vis spectra of Pani/ZnO nanocomposite were studied to investigate the optical behavior after doping the ZnO nanoparticle into the polymer matrix. The inclusion of ZnO nanoparticle gives rise to the red shift of π-π* transition of Pani. The nanocomposite was found to be thermally stable upto 130°C and showed conductivity value of 3.0×10−2 Scm−1.

Building an electronic resource collection a practical guide

CERN Document Server

Lee, Stuart D

2004-01-01

This practical book guides information professionals step-by-step through building and managing an electronic resource collection. It outlines the range of electronic products currently available in abstracting and indexing, bibliographic, and other services and then describes how to effectively select, evaluate and purchase them.

Analysis of Human Resources Management Strategy in China Electronic Commerce Enterprises

Science.gov (United States)

Shao, Fang

The paper discussed electronic-commerce's influence on enterprise human resources management, proposed and proved the human resources management strategy which electronic commerce enterprise should adopt from recruitment strategy to training strategy, keeping talent strategy and other ways.

Assessment of morphology and property of graphene oxide-hydroxypropylmethylcellulose nanocomposite films.

Science.gov (United States)

Ghosh, Tapas Kumar; Gope, Shirshendu; Mondal, Dibyendu; Bhowmik, Biplab; Mollick, Md Masud Rahaman; Maity, Dipanwita; Roy, Indranil; Sarkar, Gunjan; Sadhukhan, Sourav; Rana, Dipak; Chakraborty, Mukut; Chattopadhyay, Dipankar

2014-05-01

Graphene oxide (GO) was synthesized by Hummer's method and characterized by using Fourier transform infrared spectroscopy and Raman spectroscopy. The as synthesized GO was used to make GO/hydroxypropylmethylcellulose (HPMC) nanocomposite films by the solution mixing method using different concentrations of GO. The nanocomposite films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and thermo-gravimetric analysis. Mechanical properties, water absorption property and water vapor transmission rate were also measured. XRD analysis showed the formation of exfoliated HPMC/GO nanocomposites films. The FESEM results revealed high interfacial adhesion between the GO and HPMC matrix. The tensile strength and Young's modulus of the nanocomposite films containing the highest weight percentage of GO increased sharply. The thermal stability of HPMC/GO nanocomposites was slightly better than pure HPMC. The water absorption and water vapor transmission rate of HPMC film was reduced with the addition of up to 1 wt% GO. Copyright © 2014 Elsevier B.V. All rights reserved.

Functionally graded Nylon-11/silica nanocomposites produced by selective laser sintering

International Nuclear Information System (INIS)

Chung, Haseung; Das, Suman

2008-01-01

Selective laser sintering (SLS), a layered manufacturing-based freeform fabrication approach was explored for constructing three-dimensional structures in functionally graded polymer nanocomposites. Here, we report on the processing and properties of functionally graded polymer nanocomposites of Nylon-11 filled with 0-10% by volume of 15 nm fumed silica nanoparticles. SLS processing parameters for the different compositions were developed by design of experiments (DOE). The densities and micro/nanostructures of the nanocomposites were examined by optical microscopy and transmission electron microscopy (TEM). The tensile and compressive properties for each composition were then tested. These properties exhibit a nonlinear variation as a function of filler volume fraction. Finally, two component designs exhibiting a one-dimensional polymer nanocomposite material gradient were fabricated. The results indicate that particulate-filled functionally graded polymer nanocomposites exhibiting a one-dimensional composition gradient can be successfully processed by SLS to produce three-dimensional components with spatially varying mechanical properties

Single-ion conducting polymer-silicate nanocomposite electrolytes for lithium battery applications

International Nuclear Information System (INIS)

Kurian, Mary; Galvin, Mary E.; Trapa, Patrick E.; Sadoway, Donald R.; Mayes, Anne M.

2005-01-01

Solid-state polymer-silicate nanocomposite electrolytes based on an amorphous polymer poly[(oxyethylene) 8 methacrylate], POEM, and lithium montmorillonite clay were fabricated and characterized to investigate the feasibility of their use as 'salt-free' electrolytes in lithium polymer batteries. X-ray scattering and transmission electron microscopy studies indicate the formation of an intercalated morphology in the nanocomposites due to favorable interactions between the polymer matrix and the clay. The morphology of the nanocomposite is intricately linked to the amount of silicate in the system. At low clay contents, dynamic rheological testing verifies that silicate incorporation enhances the mechanical properties of POEM, while impedance spectroscopy shows an improvement in electrical properties. With clay content ≥15 wt.%, mechanical properties are further improved but the formation of an apparent superlattice structure correlates with a loss in the electrical properties of the nanocomposite. The use of suitably modified clays in nanocomposites with high clay contents eliminates this superstructure formation, yielding materials with enhanced performance

Electrodeposition of Polypyrrole/Reduced Graphene Oxide/Iron Oxide Nanocomposite as Supercapacitor Electrode Material

Directory of Open Access Journals (Sweden)

Y. C. Eeu

2013-01-01

Full Text Available Polypyrrole (PPy was reinforced with reduced graphene oxide (RGO and iron oxide to achieve electrochemical stability and enhancement. The ternary nanocomposite film was prepared using a facile one-pot chronoamperometry approach, which is inexpensive and experimentally friendly. The field emission scanning electron microscopy (FESEM image shows a layered morphology of the ternary nanocomposite film as opposed to the dendritic structure of PPy, suggesting hybridization of the three materials during electrodeposition. X-ray diffraction (XRD profile shows the presence of Fe2O3 in the ternary nanocomposite. Cyclic voltammetry (CV analysis illustrates enhanced current for the nanocomposite by twofold and fourfold compared to its binary (PPy/RGO and individual (PPy counterparts, respectively. The ternary nanocomposite film exhibited excellent specific capacitance retention even after 200 cycles of charge/discharge.

Using XML Technologies to Organize Electronic Reference Resources

OpenAIRE

Huser, Vojtech; Del Fiol, Guilherme; Rocha, Roberto A.

2005-01-01

Provision of access to reference electronic resources to clinicians is becoming increasingly important. We have created a framework for librarians to manage access to these resources at an enterprise level, rather than at the individual hospital libraries. We describe initial project requirements, implementation details, and some preliminary results.

P-nitrophenol degradation using N-doped reduced graphene-CdS nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Gharedaghi, Sepideh [Department of Physics, Islamic Azad University, Tehran (Iran, Islamic Republic of); Kimiagar, Salimeh [Nano Research Lab (NRL), Department of Physics, Islamic Azad University, Tehran (Iran, Islamic Republic of); Safa, Saeed [Young Researchers and Elite Club, Islamic Azad University, Tehran (Iran, Islamic Republic of)

2018-02-15

A series of nitrogen doped reduce graphene-CdS (NRGC) nanocomposites were successfully synthesized by using hydrothermal method. The structure and morphology of the samples were characterized by using FTIR, XRD, SEM, and PL. Photocatalytic activity of the nanocomposites for removing P-nitrophenol (PNP) pollutant was studied under both ultra-violet (UV) and visible light irradiation. The results show that NRGC nanocomposites exhibited higher photocatalytic activity than pure CdS. The degradation rate significantly increased to 50 and 70% by the addition of nitrogen doped reduced graphene oxide (NRGO) to CdS under UV and visible irradiation, respectively. Higher photocatalytic activity of the nanocomposites was due to the role of NRGO as an excellent electron acceptor and transporter. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

An Innovative Electrolysis Approach for the Synthesis of Metal Matrix Bulk Nanocomposites: A Case Study on Copper-Niobium System

Science.gov (United States)

Shokrvash, Hussein; Rad, Rahim Yazdani; Massoudi, Abouzar

2018-04-01

Design and synthesis of a prototype Cu-Nb nanocomposite are presented. Oxygen-free Cu-Nb nanocomposites were prepared using an electrolysis facility with special emphasis on the cathodic deoxidation of Cu and nanometric Nb2O5 blends in a molten NaCl-CaCl2 electrolyte. The as-prepared nanocomposites were characterized by X-ray diffraction and energy-dispersive X-ray spectroscopy. The elemental analysis of the Cu matrix and Nb phase revealed the high solubility of Nb in the Cu structure (0.85 at. pct) and Cu in the Nb structure (10.59 at. pct) over short synthesis times (4-5 hours). Furthermore, precise analysis using field emission scanning electron microscopy and transmission electron microscopy confirmed the unique structure and nanocomposite morphology of the Cu-Nb nanocomposite. The successful synthesis of Cu-Nb nanocomposites offers a new conceptual and empirical outlook on the generation of bulk nanostructures of immiscible bimetals using electro-synthesis.

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.

Novel ZnWO4/RGO nanocomposite as high performance photocatalyst

Directory of Open Access Journals (Sweden)

Mohamed Jaffer Sadiq Mohamed

2017-01-01

Full Text Available In this study, we report the synthesis of nanocomposite material composed of zinc tungstate (ZnWO4 and reduced graphene oxide (RGO as photocatalyst by a simple microwave irradiation technique. The prepared nanocomposites have been characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, energy dispersive X-ray (EDX analysis, X-ray photoelectron spectroscopy (XPS, Fourier transform infrared spectrometer (FTIR, photoluminescence spectroscopy (PL and UV-Visible spectroscopy. The photocatalytic activities of the prepared nanocomposites are evaluated in terms of the efficiencies of photodegradation of methylene blue (MB dye in aqueous solution under visible light irradiation. The prepared nanocomposites showed excellent photodegradation efficiency compared to the commercial TiO2 under visible light irradiation. The activity of the catalyst towards methyl orange (MO and rhodamine B (RB was also good. Further, in view of the low cost, simple preparation method and high catalytic activity of the material, it is expected that the prepared nanocomposite can serve as an environment friendly photocatalyst for treating the large scale industrial waste waters.

Functional energy nanocomposites surfaces based on mesoscopic microspheres, polymers and graphene flakes

Science.gov (United States)

Alekseev, S. A.; Dmitriev, A. S.; Dmitriev, A. A.; Makarov, P. G.; Mikhailova, I. A.

2017-11-01

In recent years, there has been a great interest in the development and creation of new functional energy materials, including for improving the energy efficiency of power equipment and for effectively removing heat from energy devices, microelectronics and optoelectronics (power micro electronics, supercapacitors, cooling of processors, servers and Data centers). In this paper, the technology of obtaining a new nanocomposite based on mesoscopic microspheres, polymers and graphene flakes is considered. The methods of sequential production of functional materials from graphite flakes of different volumetric concentration using polymers based on epoxy resins and polyimide, as well as the addition of a mesoscopic medium in the form of monodisperse microspheres are described. The data of optical and electron microscopy of such nanocomposites are presented, the main problems in the appearance of defects in such materials are described, the possibilities of their elimination by the selection of different concentrations and sizes of the components. Data are given on the measurement of the hysteresis of the contact angle and the evaporation of droplets on similar substrates. The results of studying the mechanical, electrophysical and thermal properties of such nanocomposites are presented. Particular attention is paid to the investigation of the thermal conductivity of these nanocomposites with respect to the creation of thermal interface materials for cooling devices of electronics, optoelectronics and power engineering.

Electronic Resources and Mission Creep: Reorganizing the Library for the Twenty-First Century

Science.gov (United States)

Stachokas, George

2009-01-01

The position of electronic resources librarian was created to serve as a specialist in the negotiation of license agreements for electronic resources, but mission creep has added more functions to the routine work of electronic resources such as cataloging, gathering information for collection development, and technical support. As electronic…

Polystyrene/magnetite nanocomposite synthesis and characterization: investigation of magnetic and electrical properties for using as microelectromechanical systems (MEMS

Directory of Open Access Journals (Sweden)

Omidi Mohammad Hassan

2017-02-01

Full Text Available In this work, a novel polystyrene/Fe3O4 nanocomposite prepared by in-situ method is presented. Magnetic Fe3O4 nanoparticles were encapsulated by polystyrene. The FT-IR spectra confirmed polystyrene/Fe3O4 nanocomposite preparation. The electrical properties of prepared nanocomposite were investigated by cyclic voltammetry (CV. The CV analysis showed good electrical conductivity of the synthesized nanocomposite. Magnetic properties of the nanocomposite were studied by vibrating sample magnetometer (VSM. The VSM analysis confirmed magnetic properties of the nanocomposite. The morphology and the size of the synthesized nanocomposite were investigated by field emission scanning electron microscope (FESEM. According to the VSM and CV results, such nanocomposite can be used in microelectromechanical systems.

Colloidal titania-silica-iron oxide nanocomposites and the effect from silica thickness on the photocatalytic and bactericidal activities

Energy Technology Data Exchange (ETDEWEB)

Chanhom, Padtaraporn [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Charoenlap, Nisanart [Laboratory of Biotechnology, Chulabhorn Research Institute, Bangkok 10210 (Thailand); Tomapatanaget, Boosayarat [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Insin, Numpon, E-mail: Numpon.I@chula.ac.th [Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand)

2017-04-01

New types of colloidal multifunctional nanocomposites that combine superparamagnetic character and high photocatalytic activity were synthesized and investigated. The superparamagnetic nanocomposites composed of anatase titania, silica, and iron oxide nanoparticles (TSI) were synthesized using thermal decomposition method followed by microemulsion method, without calcination at high temperature. Different techniques including X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to characterize and confirm the structure of the nanocomposites. These nanocomposites showed high photocatalytic activity when used in the photodegradation of methylene blue under irradiation with a black light lamp. Moreover, the nanocomposites exhibited high antibacterial properties. From our study, the nanocomposites can be useful in various applications such as removal of pollutants with readily separation from the environment using an external magnetic field. These composites could effectively photo-degrade the dye at least three cycles without regeneration. The effects of silica shell thickness on the photocatalytic activity was investigated, and the thickness of 6 nm of the silica interlayer is enough for the inhibition of electron translocation between titania and iron oxide nanoparticles and maintaining the efficiency of photocatalytic activity of titania nanoparticles. - Highlights: • New colloidal nanocomposites of iron oxide-silica-titania were prepared. • The nanocomposites exhibited high photocatalytic activity with magnetic response. • The effects of silica thickness on photocatalytic activity were investigated. • Bactericidal activity of the nanocomposites was demonstrated.

Structural and optical characterization of In_2O_3/PANI nanocomposite prepared by in-situ polymerization

International Nuclear Information System (INIS)

Janeoo, Shashi; Sharma, Mamta; Goswamy, J.; Singh, Gurinder

2016-01-01

Polyaniline-indium oxide (In_2O_3/PANI) nanocomposite have been prepared by in-situ polymerization of aniline and as-synthesized In_2O_3 nanoparticles. X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transformation infrared (FTIR) and UV/Vis spectroscopy techniques are used to investigate the structural and optical properties of In_2O_3/PANI nanocomposite. TEM analysis shows In_2O_3 nanoparticles are embedded in PANI nanofibers. FTIR spectra show the good interactions between PANI nanofibers and In_2O_3 nanoparticles. The band gap and electronic transitions in In_2O_3/PANI nanocomposite is determined by using UV/Vis spectra.

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.

Fabrication of CDs/CdS-TiO2 ternary nano-composites for photocatalytic degradation of benzene and toluene under visible light irradiation

Science.gov (United States)

Wang, Meng; Hua, Jianhao; Yang, Yaling

2018-06-01

An efficient cadmium sulfide quantum-dots (CdS QDs) and carbon dots (CDs) modified TiO2 photocatalyst (CdS/CDs-TiO2) was successfully fabricated. The as-prepared ternary nano-composites simultaneously improved the photo-corrosion of CdS and amplified its photocatalytic activity. The introduction of CdS QDs and CDs could enhance more absorbance of light, prevent the undesirable electron/hole recombination, and promote charge separation, which was important for the continuous formation of rad OH and rad O2- radicals. When the optimal mass ratio of CdS QDs to CDs was 3:1, above 90% degradation efficiencies were achieved for benzene within 1 h and toluene in 2 h, while that of pure TiO2 (P25), CdS QDs-TiO2, CDs-TiO2 nano-composites was around 15%. Owing to the symmetric structure and conjugation of methyl with benzene ring, the degradation of toluene was more difficult than benzene to carry on. The new fabricated nano-composites showed good prospective application of cleaning up refractory pollutants and the resource utilization.

Surface properties of UV irradiated PC–TiO{sub 2} nanocomposite film

Energy Technology Data Exchange (ETDEWEB)

Jaleh, B., E-mail: bkjaleh@yahoo.com; Shahbazi, N.

2014-09-15

Highlights: • Production of PC–TiO{sub 2} nanocomposite films. • Fully characterization of PC–TiO{sub 2} nanocomposite films. • Influence of UV irradiation on surface properties and hardness of PC–TiO{sub 2} nanocomposite film. - Abstract: In this work, polycarbonate–TiO{sub 2} nanocomposite films were prepared with two different percentages. The structure of samples were studied by X-ray diffraction. Thermal stability of the nanocomposites was studied by thermogravimetric analysis (TGA). The polycarbonate and polycarbonate–TiO{sub 2} nanocomposite films were exposed by UV light at different irradiation times. The effects of UV irradiation on the surface properties of samples have been studied by different characterization techniques, viz. scanning electron microscopy (SEM), FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle measurement and Vickers microhardness tester. Hydrophilicity and surface energy of UV treated samples varied depending on UV irradiation time. TGA curves showed that nanocomposite films have higher resistance to thermal degradation compared to polycarbonate. XPS analysis shows that surface of samples become more oxidized due to UV irradiation. For nanocomposite film, the smallest contact angle was observed in association with the longest UV irradiation time. The contact angle significantly decreased from 90° to 12° after 15 h of UV irradiation. It is observed that the hardness of the nanocomposite films increases after UV irradiation.

Synthesis of NiO@MnO_2 core/shell nanocomposites for supercapacitor application

International Nuclear Information System (INIS)

Chen, Junjiao; Huang, Ying; Li, Chao; Chen, Xuefang; Zhang, Xiang

2016-01-01

Graphical abstract: - Highlights: • MnO_2 nanosheets were grown on the surface of porous NiO microtube. • The NiO@MnO_2 nanocomposite exhibits excellent cycle performance. • The nanocomposite exhibits specific capacitance of 266.7 F g"−"1 at 0.5 A g"−"1. - Abstract: In this work, NiO@MnO_2 core/shell nanocomposites were fabricated by a two-step method. The morphology and structure of the nanocomposites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction analysis and thermal gravity analysis. In addition, the supercapacitive performances were examined by cyclic voltammogram (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS). The electrochemical results indicate that the composite exhibits a specific capacitance of 266.7 F g"−"1 at 0.5 A g"−"1 and excellent cycling stability (81.7% retention after 2000 cycles at 1 A g"−"1). Therefore, this wok offers meaningful reference for supercpacitor applications in the future.

Hydrothermal synthesis of graphene/nickel oxide nanocomposites used as the electrode for supercapacitors.

Science.gov (United States)

Zhou, Zhongnian; Ni, Haifang; Fan, Li-Zhen

2014-07-01

Graphene (GR)-based nanocomposites with different mass ratios of NiO and GR are prepared via hydrothermal method using Ni(NO3)2 as the origin of nickel and urea as the hydrolysis-controlling agent. The morphology and electrochemical performance of the GR/NiO nanocomposites are closely associated with the mass ratios of GR to NiO. The chemical composition and morphology of the composites together with the pure GR and NiO are characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM). It is found that the GR sheets and NiO particles form uniform nanocomposites with the NiO particles absorbed on the GR surface. A specific capacitance of 384 F g(-1) at a current density of 0.1 A g(-1) is achieved when the coating amount of NiO is up to 74 wt%. In addition, the attenuation of the specific capacitance is less than 6% after 500 cycles, indicating such nanocomposite has excellent cycling performance.

Nanocomposites: synthesis, structure, properties and new application opportunities

Directory of Open Access Journals (Sweden)

Pedro Henrique Cury Camargo

2009-03-01

Full Text Available Nanocomposites, a high performance material exhibit unusual property combinations and unique design possibilities. With an estimated annual growth rate of about 25% and fastest demand to be in engineering plastics and elastomers, their potential is so striking that they are useful in several areas ranging from packaging to biomedical applications. In this unified overview the three types of matrix nanocomposites are presented underlining the need for these materials, their processing methods and some recent results on structure, properties and potential applications, perspectives including need for such materials in future space mission and other interesting applications together with market and safety aspects. Possible uses of natural materials such as clay based minerals, chrysotile and lignocellulosic fibers are highlighted. Being environmentally friendly, applications of nanocomposites offer new technology and business opportunities for several sectors of the aerospace, automotive, electronics and biotechnology industries.

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.

Polypyrrole-palladium nanocomposite coating of micrometer-sized polymer particles toward a recyclable catalyst.

Science.gov (United States)

Fujii, Syuji; Matsuzawa, Soichiro; Hamasaki, Hiroyuki; Nakamura, Yoshinobu; Bouleghlimat, Azzedine; Buurma, Niklaas J

2012-02-07

A range of near-monodisperse, multimicrometer-sized polymer particles has been coated with ultrathin overlayers of polypyrrole-palladium (PPy-Pd) nanocomposite by chemical oxidative polymerization of pyrrole using PdCl(2) as an oxidant in aqueous media. Good control over the targeted PPy-Pd nanocomposite loading is achieved for 5.2 μm diameter polystyrene (PS) particles, and PS particles of up to 84 μm diameter can also be efficiently coated with the PPy-Pd nanocomposite. The seed polymer particles and resulting composite particles were extensively characterized with respect to particle size and size distribution, morphology, surface/bulk chemical compositions, and conductivity. Laser diffraction studies of dilute aqueous suspensions indicate that the polymer particles disperse stably before and after nanocoating with the PPy-Pd nanocomposite. The Fourier transform infrared (FT-IR) spectrum of the PS particles coated with the PPy-Pd nanocomposite overlayer is dominated by the underlying particle, since this is the major component (>96% by mass). Thermogravimetric and elemental analysis indicated that PPy-Pd nanocomposite loadings were below 6 wt %. The conductivity of pressed pellets prepared with the nanocomposite-coated particles increased with a decrease of particle diameter because of higher PPy-Pd nanocomposite loading. "Flattened ball" morphologies were observed by scanning/transmission electron microscopy after extraction of the PS component from the composite particles, which confirmed a PS core and a PPy-Pd nanocomposite shell morphology. X-ray diffraction confirmed the production of elemental Pd and X-ray photoelectron spectroscopy studies indicated the existence of elemental Pd on the surface of the composite particles. Transmission electron microscopy confirmed that nanometer-sized Pd particles were distributed in the shell. Near-monodisperse poly(methyl methacrylate) particles with diameters ranging between 10 and 19 μm have been also successfully

Preparation, characterization, and antibacterial activity of silver nanoparticle-decorated graphene oxide nanocomposite.

Science.gov (United States)

Shao, Wei; Liu, Xiufeng; Min, Huihua; Dong, Guanghui; Feng, Qingyuan; Zuo, Songlin

2015-04-01

In this work, we report a facile and green approach to prepare a uniform silver nanoparticles (AgNPs) decorated graphene oxide (GO) nanocomposite (GO-Ag). The nanocomposite was fully characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectra, ultraviolet-visible (UV-vis) absorption spectra, and X-ray photoelectron spectroscopy (XPS), which demonstrated that AgNPs with a diameter of approximately 22 nm were uniformly and compactly deposited on GO. To investigate the silver ion release behaviors, HEPES buffers with different pH (5.5, 7, and 8.5) were selected and the mechanism of release actions was discussed in detail. The cytotoxicity of GO-Ag nanocomposite was also studied using HEK 293 cells. GO-Ag nanocomposite displayed good cytocompatibility. Furthermore, the antibacterial properties of GO-Ag nanocomposite were studied using Gram-negative E. coli ATCC 25922 and Gram-positive S. aureus ATCC 6538 by both the plate count method and disk diffusion method. The nanocomposite showed excellent antibacterial activity. These results demonstrated that GO-Ag nanocomposite, as a kind of antibacterial material, had a great promise for application in a wide range of biomedical applications.

DC bias effect on alternating current electrical conductivity of poly(ethylene terephthalate)/alumina nanocomposites

Science.gov (United States)

Nikam, Pravin N.; Deshpande, Vineeta D.

2016-05-01

Polymer nanocomposites based on metal oxide (ceramic) nanoparticles are a new class of materials with unique properties and designed for various applications such as electronic device packaging, insulation, fabrication and automotive industries. Poly(ethylene terephthalate) (PET)/alumina (Al2O3) nanocomposites with filler content between 1 wt% and 5 wt% were prepared by melt compounding method using co-rotating twin screw extruder and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and precision LCR meter techniques. The results revealed that proper uniform dispersion at lower content up to 2 wt% of nano-alumina observed by using TEM. Aggregation of nanoparticles was observed at higher content of alumina examined by using SEM and TEM. The frequency dependences of the alternating current (AC) conductivity (σAC) of PET/alumina nanocomposites on the filler content and DC bias were investigated in the frequency range of 20Hz - 1MHz. The results showed that the AC and direct current (DC) conductivity increases with increasing DC bias and nano-alumina content upto 3 wt%. It follows the Jonscher's universal power law of solids. It revealed that σAC of PET/alumina nanocomposites can be well characterized by the DC conductivity (σDC), critical frequency (ωc), critical exponent of the power law (s). Roll of DC bias potential led to an increase of DC conductivity (σDC) due to the creation of additional conducting paths with the polymer nanocomposites and percolation behavior achieved through co-continuous morphology.

Pt/AlPO{sub 4} nanocomposite thin-film electrodes for ethanol electrooxidation

Energy Technology Data Exchange (ETDEWEB)

Oh, Yuhong; Kang, Joonhyeon; Nam, Seunghoon; Byun, Sujin [WCU Hybrid Materials Program, Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-744 (Korea, Republic of); Park, Byungwoo, E-mail: byungwoo@snu.ac.kr [WCU Hybrid Materials Program, Department of Materials Science and Engineering, Research Institute of Advanced Materials, Seoul National University, Seoul 151-744 (Korea, Republic of)

2012-07-16

The enhanced catalytic properties toward ethanol electrooxidation on Pt/AlPO{sub 4} nanocomposite thin-film electrodes were investigated. The Pt/AlPO{sub 4} nanocomposites with various Al/Pt ratios (0.27, 0.57, and 0.96) were fabricated by a co-sputtering method. All of the Pt/AlPO{sub 4} nanocomposites showed a negative shift in the onset potential and a higher current density than those of pure Pt electrode for the electrooxidation of ethanol. Among the various Pt/AlPO{sub 4} nanocomposite thin-film electrodes, the electrode with an atomic ratio of Al to Pt of 0.57 showed the highest electrocatalytic activity for ethanol electrooxidation. The activation enthalpy for the optimum Pt/AlPO{sub 4} nanocomposite was approximately 0.05 eV lower than that of pure Pt. It is believed that the enhancement in catalytic activity is due to the electron-rich Pt resulting from the Fermi-energy difference between Pt and AlPO{sub 4}. - Highlights: Black-Right-Pointing-Pointer The enhanced ethanol electrooxidation on Pt/AlPO{sub 4} nanocomposites is investigated. Black-Right-Pointing-Pointer The Pt/AlPO{sub 4} exhibits higher current density and lower onset potential than pure Pt. Black-Right-Pointing-Pointer The activation enthalpy for optimum Pt/AlPO{sub 4} electrode is {approx}0.05 eV lower than pure Pt. Black-Right-Pointing-Pointer XPS shows electron-rich Pt due to Fermi-energy difference between Pt and AlPO{sub 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

Ag nanocrystals anchored CeO{sub 2}/graphene nanocomposite for enhanced supercapacitor applications

Energy Technology Data Exchange (ETDEWEB)

Vanitha, M.; Keerthi [Department of Chemical Engineering, A.C Tech, Anna University, Chennai 600025 (India); Cao, P. [Department of Chemical and Materials Engineering, The University of Auckland, PB 92019, Auckland 1142 (New Zealand); Balasubramanian, N., E-mail: nbsbala@annauniv.edu [Department of Chemical Engineering, A.C Tech, Anna University, Chennai 600025 (India)

2015-09-25

Highlights: • Quasi spherical Ag and CeO{sub 2} nanoparticles were decorated on rGO matrix. • The Ag/CeO{sub 2}/rGO nanocomposite exhibits specific capacitance of 710 F g{sup −1}. • Ag plays an imperative role in improving the electrochemical performance. - Abstract: A novel ternary Ag decorated CeO{sub 2}/reduced graphene oxide (rGO) nanocomposite was synthesized by a facile hydrothermal method with polyvinylpyrrolidone (PVP) as surface directing agent and was designed as an electrode material for supercapacitors application. The structure and morphology of the nanocomposites were analyzed by X-ray diffraction analysis (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The synergistic effect between the CeO{sub 2} nanoparticles wrapped rGO matrix with Ag nanoparticles gives rise to a nanostructure, empowering the material with enhanced electrochemical performance. The electrochemical characterization was performed using cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopic studies in 3 M KOH aqueous electrolyte. The nanocomposite electrode materials possess a high specific capacitance of 710.42 F g{sup −1} at an applied current density of 0.2 A g{sup −1}, which was nearly two fold higher than CeO{sub 2}/rGO nanocomposite. This work endows a new route for building Ag/CeO{sub 2}/rGO ternary nanocomposite which will have some impact on the exploitation of novel ternary electrode materials for supercapacitor applications.

Polyaniline nanocomposites via in situ emulsion polymerization based on montmorillonite: Preparation and characterization

Directory of Open Access Journals (Sweden)

M.A. Abd El-Ghaffar

2015-11-01

Full Text Available Polyaniline nanocomposites were prepared via in situ emulsion polymerization in the presence of Na+ montmorillonite (Na+MMT. For achieving this purpose the clay was organophilized to (MMT-CTA form using cetyltrimethyl ammonium bromide (CTAB. The X-ray diffraction (XRD demonstrated that the basal space of Na+-montmorillonite increased after the organophilization from 11.21 to 19.35 Å. Polyaniline/montmorillonite (PAn/MMT nanocomposites were prepared by intercalating the emulsion of aniline monomer with treated organically layers of (Na+-MMT using ammonium peroxydisulfate (APS as an initiator. Furthermore aniline hydrochloride (AnHCl was used as a modifier and monomer to prepare PAn/H+MMT nanocomposites by cation exchange of the anilinuim moiety with the sodium ion inside the basal spaces which enlarged after the polymerization process to 35 Å as evidenced from X-ray diffraction (XRD. The d-spacing of the PAn/H+-MMT nanocomposite was found to become wider about 23.79 Å than that of the pure Na+-MMT, and successful intercalation or exfoliation of PAnH+ into Na+-MMT layers. The prepared PAn/MMT nanocomposites were characterized by thermal gravimetric analysis (TGA, scanning electron microscope (SEM, and transmission electron microscope (TEM. The electrical property measurements showed an enhancement in the conductivity values of the prepared nanocomposites especially on using AnHCl monomer to be in the order of 10−1 S/cm.

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.

Elastomeric Nanocomposite Based on Exfoliated Graphene Oxide and Its Characteristics without Vulcanization

Directory of Open Access Journals (Sweden)

Nasser Abdullah Habib

2017-01-01

Full Text Available Rubber nanocomposites have emerged as one of the advanced materials in recent years. The aim of this work was to homogeneously disperse graphene oxide (GO sheets into Nitrile Butadiene Rubber (NBR and investigate the characteristics of GO/NBR nanocomposite without vulcanization. A suitable solvent was found to dissolve dry NBR while GO was exfoliated completely in an aqueous base solution using sonication. GO was dispersed into NBR at different loadings by solution mixing to produce unvulcanized GO/NBR nanocomposites. Scanning Electron Microscopy (SEM, Fourier-Transform Infrared Spectroscopy (FTIR, and X-Ray Diffraction (XRD were used to characterize the samples. Furthermore, mechanical and electrical properties of unvulcanized GO/NBR nanocomposites were carried out to determine the influence of GO on the NBR properties. The results showed that the modulus of GO/NBR nanocomposite at 1 wt% of GO was enhanced by about 238% compared with unfilled NBR. These results provide insight into the properties of unvulcanized GO/NBR nanocomposite for application as coatings or adhesives.

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.

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.

A facile synthesis and spectral characterization of Cu{sup 2+} doped CdO/ZnS nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Joyce Stella, R.; Thirumala Rao, G.; Babu, B.; Pushpa Manjari, V. [Department of Physics, University College of Sciences, Acharya Nagarjuna University, Nagarjuna Nagar, AP 522510 (India); Reddy, Ch. Venkata; Shim, Jaesool [School of Mechanical Engineering, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Ravikumar, R.V.S.S.N., E-mail: rvssn@yahoo.co.in [Department of Physics, University College of Sciences, Acharya Nagarjuna University, Nagarjuna Nagar, AP 522510 (India)

2015-06-15

A facile two-step method is demonstrated for the preparation of Cu{sup 2+} doped CdO/ZnS nanocomposite. Systematic investigations like X-ray diffraction (XRD), Scanning electron microscopy (SEM) with EDS, transmission electron microscopy (TEM), FT-IR, electron paramagnetic resonance (EPR), optical absorption, photoluminescence (PL) and magnetic studies are carried out for the prepared material. From powder XRD, the nanocomposites are comprised for cubic phase of both CdO and ZnS in a close contact with each other. The ground state wave function of dopant ions has been estimated from EPR studies. Optical and EPR data confirm that doped Cu{sup 2+}ions occupy rhombically distorted octahedral sites with the host material. Due to doping, band gap has been changed and blue shifts occurred in PL. Magnetic measurements indicate a possible ferromagnetic response, associated to the exchange interaction between local spin-polarized electrons of Cu{sup 2+} ions and conductive electrons. - Graphical abstract: M–H curve of Cu{sup 2+} doped CdO–ZnS nanocomposites. The magnetic properties of Cu{sup 2+} doped CdO/ZnS nanocomposite has been investigated using vibrating sample magnetometer given as magnetization and hysteresis (M–H) curve. The magnetization curve with noticeable coercivity of M–H loop clearly indicate the existence of ferromagnetic ordering in Cu{sup 2+} doped CdO/ZnS nanocomposite at room temperature. According to the Ruderman–Kittel–Kasuya–Yosida (RKKY) theory, the exchange interaction between local spin-polarized electrons (such as the electrons of Cu{sup 2+} ions) and conductive electrons is the main cause that leads to the ferromagnetism. Coercivity (Hc) of the field is about 98 Oe, saturation magnetization (Ms) and remnant magnetization (Mr) of present sample is estimated to be 15.8×10{sup −3} and 1.43×10{sup −3} emu/g respectively. The ferromagnetism observed in the prepared material is not commencing with other impurities but expected to

Reduced Graphene Oxide/Au Nanocomposite for NO2 Sensing at Low Operating Temperature

Directory of Open Access Journals (Sweden)

Hao Zhang

2016-07-01

Full Text Available A reduced grapheme oxide (rGO/Au hybrid nanocomposite has been synthesized by hydrothermal treatment using graphite and HAuCl4 as the precursors. Characterization, including X-ray diffraction (XRD, Raman spectra, X-ray photoelecton spectroscopy (XPS and transmission electron microscopy (TEM, indicates the formation of rGO/Au. A gas sensor fabricated with rGO/Au nanocomposite was applied for NO2 detection at 50 °C. Compared with pure rGO, rGO/Au nanocomposite exhibits higher sensitivity, a more rapid response–recovery process and excellent reproducibility.

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.

Electronic Resources Management System: Recommendation Report 2017

KAUST Repository

Ramli, Rindra M.

2017-01-01

This recommendation report provides an overview of the selection process for the new Electronic Resources Management System. The library has decided to move away from Innovative Interfaces Millennium ERM module. The library reviewed 3 system

Biopolymer nanocomposites: processing, properties, and applications (wiley series on polymer engineering and technology)

CERN Document Server

2013-01-01

Interest in biopolymer nanocomposites is soaring. Not only are they green and sustainable materials, they can also be used to develop a broad range of useful products with special properties, from therapeutics to coatings to packaging materials. With contributions from an international team of leading nanoscientists and materials researchers, this book draws together and reviews the most recent developments and techniques in biopolymer nano-composites. It describes the preparation, processing, properties, and applications of bio- polymer nanocomposites developed from chitin, starch, and cellulose, three renewable resources.Biopolymer Nanocomposites features a logical organization and approach that make it easy for readers to take full advantage of the latest science and technology in designing these materials and developing new products and applications. It begins with a chapter reviewing our current understanding of b...

One-pot synthesis of a Ni–Mn3O4 nanocomposite for supercapacitors

International Nuclear Information System (INIS)

Xu, Guo-rong; Shi, Jin-jin; Dong, Wen-hao; Wen, Ya; Min, Xiang-ping; Tang, An-ping

2015-01-01

Highlights: • Ni–Mn 3 O 4 nanocomposites have been synthesized simply. • Mn 3 O 4 particles were deposited on surface of Ni particles with OH functional groups. • Ni–Mn 3 O 4 composites could be quickly conditioned to birnessite-type MnO 2 . • A specific capacitance of 230 F g −1 was obtained for Ni (17.3%)–Mn 3 O 4 nanocomposite. - Abstract: Ni–Mn 3 O 4 nanocomposite has been prepared successfully by chemical oxidation in an alkaline solution of Mn 2+ on the surface of Ni nanoparticles with OH functional groups using one-pot method. The obtained Ni–Mn 3 O 4 nanocomposite was characterized using a scanning electron microscope (SEM), a transmission electron microscope (TEM), X-ray diffraction (XRD) analysis and various electrochemical techniques, such as cyclic voltammetry (CV), galvanostatic charge/discharge (GC/D) and electrochemical impedance spectroscopy (EIS). The average crystal sizes of Mn 3 O 4 were found to decrease linearly with increasing Ni content in the Ni–Mn 3 O 4 composite. The Ni–Mn 3 O 4 nanocomposite could be easily conditioned and inverted to birnessite-type MnO 2 . A specific capacitance of 230 F g −1 (based on pure Mn 3 O 4 ) was obtained for the Ni (17.3%)–Mn 3 O 4 nanocomposite at a current rate of 0.25 A g −1 , and 94% of the initial capacitance was retained after 1000 GC/D cycles at a current rate of 1 A g −1 . It is concluded that the Ni–Mn 3 O 4 nanocomposite is a promising electrode materials for supercapacitors

Novel MnOOH–graphene nanocomposites: Preparation, characterization and electrochemical properties for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Mei, Jun; Zhang, Long, E-mail: zhanglongzhl@163.com

2015-01-15

In this paper, we report a simple and controlled synthesis of novel MnOOH–graphene nanocomposites with a one-step facile hydrothermal method. It is template-free and easy to reproduce. Electrochemical properties are investigated in different media. The values of specific capacitance achieved are 112 F g{sup −1} in 1 M Na{sub 2}SO{sub 4} and 165 F g{sup −1} in 6 M KOH electrolyte, respectively. The assembly of multiple branched MnOOH and graphene flakes results in synergistic effects, forming new electron transfer channels to accelerate electron transfer and provide the pseudocapacitance to increase the overall capacitance. The novel composites have potential applications in the fields of supercapacitors, lithium battery and so on. - Graphical abstract: The MnOOH–graphene nanocomposites shows better specific capacitance with the values achieved 112 F g{sup −1} in 1 M Na{sub 2}SO{sub 4} and 165 F g{sup −1} in 6 M KOH electrolyte, respectively. - Highlights: • Novel MnOOH–graphene nanocomposites were prepared by a one-step hydrothermal method. • The assembly can form new electron transfer channels to accelerate electron transfer. • The capacitive and rate performances are enhanced in both neutral and alkaline medium.

Torsional, tensile and structural properties of acrylonitrile–butadiene–styrene clay nanocomposites

International Nuclear Information System (INIS)

Singh, Priyanka; Ghosh, Anup K.

2014-01-01

Highlights: • Torsional behaviour of ABS and its nanocomposites is established. • Rheology is used as a tool to investigate the structure development of ABS nanocomposites. • Effect of nanoclay on resilience, toughness and ductility of ABS nanoclay is quantified. • ABS clay nanocomposites is correlated with rheological, mechanical and torsional behaviour. - Abstract: Torsional and tensile behaviour of acrylonitrile–butadiene–styrene (ABS)-clay nano-composites have been investigated and correlated with morphological and rheological characterisations. Nano-composites of ABS are prepared by melt compounding with different loading levels of nanoclay (Cloisite 30B) in a twin screw extruder and have been characterised in terms of torsional, axial and impact behaviour for their application in external orthotic devices. Tensile stress strain curve of nanocomposites are investigated to quantify resilience, toughness and ductility. Torque values of the nanocomposites are observed under torsion (10°–90°) and compared with that of neat ABS. Performance of ABS under torsional load improved by addition of nanoclay. Both modulus of elasticity and rigidity are found to improve in presence of nanoclay. State of dispersion in nano-composites is investigated using conventional methods such as transmission electron microscopy (TEM), X-ray diffraction (XRD), as well as by parallel plate rheometry. Addition of clay exhibits shear thinning effect and results in increase in storage modulus as well as complex viscosity of the nanocomposites. Zero shear viscosity rises tenfold with 1–2% addition of nanoclay, indicating the formation of structural network. It is found that state of dispersion of nanoclay governs the torsional and mechanical properties in ABS-clay nanocomposites

Investigating the property profile of polyamide-alumina nanocomposite materials

International Nuclear Information System (INIS)

Sarwar, Muhammad Ilyas; Zulfiqar, Sonia; Ahmad, Zahoor

2009-01-01

Transparent sol-gel-derived nanocomposites were prepared by incorporating an alumina network into a polyamide matrix. Different amounts of aluminum butoxide were hydrolyzed and condensed to produce the alumina network. Thin composite films were characterized in terms of their optical, morphological, mechanical and thermomechanical properties. Tensile modulus, stress at both yield and break points, improved for alumina loadings of 5-10 wt.%. The glass transition temperature increased to 140 o C for nanocomposites containing 15 wt.% alumina. Scanning electron microscopy investigations indicated a uniform distribution of alumina in the polyamide matrix.

Preparation, characterization, and antibacterial activity studies of silver-loaded poly(styrene-co-acrylic acid) nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Song, Cunfeng [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Chang, Ying; Cheng, Ling; Xu, Yiting [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Chen, Xiaoling, E-mail: tinachen0628@163.com [Department of Endodontics, Xiamen Stomatology Hospital, Teaching Hospital of Fujian Medical University, Xiamen 361003 (China); Zhang, Long; Zhong, Lina [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China); Dai, Lizong, E-mail: lzdai@xmu.edu.cn [Department of Materials Science and Engineering, College of Materials, Xiamen University, Xiamen 361005 (China)

2014-03-01

A simple method for preparing a new type of stable antibacterial agent was presented. Monodisperse poly(styrene-co-acrylic acid) (PSA) nanospheres, serving as matrices, were synthesized via soap-free emulsion polymerization. Field-emission scanning electron microscopy micrographs indicated that PSA nanospheres have interesting surface microstructures and well-controlled particle size distributions. Silver-loaded poly(styrene-co-acrylic acid) (PSA/Ag-NPs) nanocomposites were prepared in situ through interfacial reduction of silver nitrate with sodium borohydride, and further characterized by transmission electron microscopy and X-ray diffraction. Their effects on antibacterial activity including inhibition zone, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and bactericidal kinetics were evaluated. In the tests, PSA/Ag-NPs nanocomposites showed excellent antibacterial activity against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli. These nanocomposites are considered to have potential application in antibacterial coatings on biomedical devices to reduce nosocomial infection rates. - Highlights: • A new type of antibacterial agent (PSA/Ag-NPs nanocomposites) was synthesized. • The antibacterial activity against S. aureus and E. coli was studied. • Inhibition zone, MIC, MBC, and bactericidal kinetics were evaluated. • PSA/Ag-NPs nanocomposites showed excellent antibacterial activity.

Synthesis, characterization and dielectric properties of polynorbornadiene–clay nanocomposites by ROMP using intercalated Ruthenium catalyst

International Nuclear Information System (INIS)

Yalçınkaya, Esra Evrim; Balcan, Mehmet; Güler, Çetin

2013-01-01

Polynorbornadiene clay nanocomposites were prepared for the first time by the ring opening metathesis polymerization (ROMP) using modified montmorillonite and polynorbornadiene the latter of which is used commonly in electric–electronic industry. The Na–MMT clay was modified by a quaternary ammonium salt containing Ruthenium complex as a suitable catalyst and intercalant as well. The norbornadiene monomers were polymerized within the modified montmorillonite layers by in-situ polymerization method in different clay loading degrees. Intercalation ability of the Ru catalyst and partially exfoliated nanocomposite structure were proved by powder X-ray Diffraction (XRD) Spectroscopy and Transmission Electron Microscopy (TEM) methods. The nanocomposite materials with high thermal degradation temperature and low dielectric constant compared to the pure polynorbornadiene were obtained. The dielectric constants decreased with the increase of the clay content. - Highlights: • Polynorbornadiene–clay nanocomposites were prepared for the first time. • Ruthenium complex was assigned as both suitable catalyst and intercalant. • The norbornadiene was polymerized by in-situ polymerization method. • Exfoliation/intercalation structures were found to be related with loading degree. • PNBD–MMT nanocomposites had a higher thermal degradation temperature and lower dielectric constant

Reduced graphene oxide/hydroxylated styrene-butadiene-styrene tri-block copolymer electroconductive nanocomposites: Preparation and properties

Energy Technology Data Exchange (ETDEWEB)

Xiong, Yuanqin; Xie, Yanyan [Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Zhang, Fan [College of Chemistry and Chemical Engineering, Jishou University, Jishou 416000 (China); Ou, Encai; Jiang, Zhuojuan; Ke, Lili; Hu, Ding [Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Xu, Weijian, E-mail: weijianxu59@gmail.com [Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

2012-08-20

Highlights: Black-Right-Pointing-Pointer RGO/HO-SBS nanocomposites are prepared successfully. Black-Right-Pointing-Pointer The introduction of -OH improves the compatibility between RGO and HO-SBS. Black-Right-Pointing-Pointer RGO disperse homogeneously and form a compact continuous network in matrix (HO-SBS). Black-Right-Pointing-Pointer The percolation threshold of the nanocomposites is of 0.2-0.5 wt% (0.09-0.23 vol%) and its conductivity is up to 1.3 S/m. - Abstract: Flexible and electroconductive nanocomposites based on reduced graphene oxide (RGO) and hydroxylated styrene-butadiene-styrene tri-block copolymer (HO-SBS) were prepared by solution blending method. By the introduction of the groups of -OH and >C=O onto SBS, the compatibility between RGO and SBS was enhanced. Field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) showed that RGO dispersed homogeneously and formed a compact continuous network in matrix (HO-SBS). The addition of RGO improved the thermal stability of the RGO/HO-SBS nanocomposites while slightly lowered the mechanical property. Moreover, RGO gave the nanocomposites a maximum electrical conductivity up to 1.3 S/m.

Multiwalled carbon nanotubes@octavinyl polyhedral oligomeric silsesquioxanes nanocomposite preparation via cross-linking reaction in acidic media

Energy Technology Data Exchange (ETDEWEB)

Somasekharan, Lakshmipriya; Thomas, Sabu [Mahatma Gandhi University, International and Interuniversity Centre for Nanoscience and Nanotechnology (India); Comoy, Corinne [Université de Lorraine, SRSMC, UMR 7565 (France); Sivasankarapillai, Anilkumar [NSS Hindu College (India); Kalarikkal, Nandakumar [Mahatma Gandhi University, International and Interuniversity Centre for Nanoscience and Nanotechnology (India); Lamouroux, Emmanuel, E-mail: Emmanuel.Lamouroux@univ-lorraine.fr [Université de Lorraine, SRSMC, UMR 7565 (France)

2016-11-15

Multiwalled carbon nanotubes have unique properties allowing their use in a wide range of applications—from microelectronics to biomedical and polymer fields. Nevertheless, a crucial aspect for their use resides in the ease of handling them during the process. Here, we report a facile route to prepare multiwalled carbon nanotubes@octavinyl polyhedral oligomeric silsesquioxanes (MWCNT@POSS) nanocomposite. The method involves the formation of a covalent bond between carboxylated MWCNTs and OV-POSS using acid-catalyzed electrophilic addition reaction. The resulting nanocomposite have been characterized by Fourier transform infrared spectroscopy (FTIR), powder X-Ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The results confirmed that the formation of MWCNT@POSS nanocomposite did not deteriorate MWCNT structure or morphology. Here, we used a 1:1 ratio of carboxylated MWCNTs and OV-POSS and the POSS content in the nanocomposite was 39.5 wt%.

One-step synthesis of graphene/SnO2 nanocomposites and its application in electrochemical supercapacitors.

Science.gov (United States)

Li, Fenghua; Song, Jiangfeng; Yang, Huafeng; Gan, Shiyu; Zhang, Qixian; Han, Dongxue; Ivaska, Ari; Niu, Li

2009-11-11

A one-step method was developed to fabricate conductive graphene/SnO2 (GS) nanocomposites in acidic solution. Graphite oxides were reduced by SnCl2 to graphene sheets in the presence of HCl and urea. The reducing process was accompanied by generation of SnO2 nanoparticles. The structure and composition of GS nanocomposites were confirmed by means of transmission electron microscopy, x-ray photoelectron and Raman spectroscopy. Moreover, the ultracapacitor characteristics of GS nanocomposites were studied by cyclic voltammograms (CVs) and electrical impedance spectroscopy (EIS). The CVs of GS nanocomposites are nearly rectangular in shape and the specific capacitance degrades slightly as the voltage scan rate is increased. The EIS of GS nanocomposites presents a phase angle close to pi/2 at low frequency, indicating a good capacitive behavior. In addition, the GS nanocomposites could be promisingly applied in many fields such as nanoelectronics, ultracapacitors, sensors, nanocomposites, batteries and gas storage.

Calcium phosphate–gold nanoparticles nanocomposite for protein adsorption and mediator-free H2O2 biosensor construction

International Nuclear Information System (INIS)

Xu Qin; Lu Guiju; Bian XiaoJun; Jin Gendi; Wang Wei; Hu Xiaoya; Wang Yang; Yang Zhanjun

2012-01-01

This work reports a new method for the preparation and application of a kind of biocompatible calcium phosphate–gold nanoparticles (Ca 3 (PO 4 ) 2 –AuNPs) nanocomposite. UV–vis spectroscopy and transmittance electron microscopy (TEM) have been used to monitor the formation process of the nanocomposite and to examine the interaction between calcium phosphate and gold nanoparticles (AuNPs). The nanocomposite has multiple sites and improved conductivity which make it suitable for the binding of proteins to construct electrochemical sensors. Myoglobin (Mb) adsorbed on the nanocomposite retained its native structure which was proved by Fourier transform infrared spectroscopy (FTIR). Direct electron transfer between the adsorbed Mb and the electrode was observed. Further results demonstrated that the adsorbed Mb has good electrocatalytic activity towards the reduction of H 2 O 2 in the absence of any mediator. Highlights: ► Using gelatin modified gold nanoparticles to prepare needle-like calcium phosphate. ► Calcium phosphate provides multiple sites for protein adsorption. ► Gold nanoparticles act as electron tunneling. ► Myoglobin adsorbed on the material showed direct electrochemistry and good catalysis.

The Structure-Property Relationship of Poly(amide-imide)/Organoclay Nanocomposites

Science.gov (United States)

Faghihi, Khalil; Soleimani, Masoumeh; Shabanian, Meisam; Abootalebi, Ashraf Sadateh

2011-06-01

Surface treated montmorillonite (MMT) was used to prepare nanocomposites with poly(amide-imide) (PAI) 5 by solution intercalation technique with various percent of organoclay (5-15 mass %). Surface modification of the MMT was performed with Cloisite 20A for ample compatibilization with the PAI matrix. The PAI 5 chains were produced through polycondensation of 4,4-diamino diphenyl sulfone 4 with N-trimellitylimido-L-alanine 3 in a medium consisting of triphenyl phosphite, N-methyl-2-pyrolidone (NMP), pyridine and calcium chloride. The PAI-Nanocomposites morphology and clay dispersion were investigated by X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The effect of clay dispersion and the interaction between clay and PAI chains on the properties of PAI-Nanocomposites films were investigated by using UV-Vis spectroscopy, thermogravimetric analysis (TGA) and water uptake measurements. Thermal stability of nanocomposites increased relative to the neat polyamide with increasing organoclay content but water uptake of these materials decreased as compared to the neat polyamide indicating reduced permeability.

Evaluation of impact strength of polyamide 6/bentonite clay nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Paz, Rene Anisio; Araujo, Edcleide Maria; Tomas Jeferson Alves; Amanda Damiao; Medeiros, Vanessa da Nobrega [Federal University of Campina Grande (CCT/UFCG), Campina Grande, PB (Brazil). Centro de Ciencias e Tecnologia; Pessan, Luiz Antonio [Federal University of Sao Carlos (DEMa/UFSCar), SP (Brazil). Materials Engineering Department

2012-07-15

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 it affects 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 Brazilian bentonite modified with a quaternary ammonium salt. X-Ray Diffraction (XRD) results showed the incorporation of salt among the layers of clay, making it organophilic and that the nanocomposites presented exfoliated and/or partially exfoliated structures and confirmed by transmission electron microscopy (TEM). By thermogravimetry (TG), the results indicated that the presence of clay increased the thermal stability of polyamide 6. The impact properties of the nanocomposites showed inferior values in relation to the pure polyamide, in other words, decrease the toughness. (author)

Evaluation of impact strength of polyamide 6/bentonite clay nanocomposites

International Nuclear Information System (INIS)

Paz, Rene Anisio; Araujo, Edcleide Maria; Tomas Jeferson Alves; Amanda Damiao; Medeiros, Vanessa da Nobrega; Pessan, Luiz Antonio

2012-01-01

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 it affects 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 Brazilian bentonite modified with a quaternary ammonium salt. X-Ray Diffraction (XRD) results showed the incorporation of salt among the layers of clay, making it organophilic and that the nanocomposites presented exfoliated and/or partially exfoliated structures and confirmed by transmission electron microscopy (TEM). By thermogravimetry (TG), the results indicated that the presence of clay increased the thermal stability of polyamide 6. The impact properties of the nanocomposites showed inferior values in relation to the pure polyamide, in other words, decrease the toughness. (author)

Decreasing Ni, Cu, Cd, and Zn heavy metal magnetite-bentonite nanocomposites and adsorption isotherm study

Science.gov (United States)

Eskandari, M.; Zakeri Khatir, M.; Khodadadi Darban, A.; Meshkini, M.

2018-04-01

This present study was conducted to investigate the effect of magnetite-bentonite nanocomposite on heavy metal removal from an effluent. For this purpose, magnetite-bentonite nanocomposite was prepared through the chemical method and characterized using x-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques, followed by studying the effect of produced nanocomposite on the removal of Ni2+, Cu2+, Cd2+, and Zn2+ heavy metal ions. The results showed that adsorption capacity of magnetite-bentonite nanocomposites for the studied ions is in the order of Zn2+ > Cd2+ > Cu2+ > Ni2+. Adsorption isotherms were drawn for Ni2+, Cu2+, Cd2+, and Zn2+ cations and found that cations adsorption on nanocomposite fit into Langmuir model.

The Internet School of Medicine: use of electronic resources by medical trainees and the reliability of those resources.

Science.gov (United States)

Egle, Jonathan P; Smeenge, David M; Kassem, Kamal M; Mittal, Vijay K

2015-01-01

Electronic sources of medical information are plentiful, and numerous studies have demonstrated the use of the Internet by patients and the variable reliability of these sources. Studies have investigated neither the use of web-based resources by residents, nor the reliability of the information available on these websites. A web-based survey was distributed to surgical residents in Michigan and third- and fourth-year medical students at an American allopathic and osteopathic medical school and a Caribbean allopathic school regarding their preferred sources of medical information in various situations. A set of 254 queries simulating those faced by medical trainees on rounds, on a written examination, or during patient care was developed. The top 5 electronic resources cited by the trainees were evaluated for their ability to answer these questions accurately, using standard textbooks as the point of reference. The respondents reported a wide variety of overall preferred resources. Most of the 73 responding medical trainees favored textbooks or board review books for prolonged studying, but electronic resources are frequently used for quick studying, clinical decision-making questions, and medication queries. The most commonly used electronic resources were UpToDate, Google, Medscape, Wikipedia, and Epocrates. UpToDate and Epocrates had the highest percentage of correct answers (47%) and Wikipedia had the lowest (26%). Epocrates also had the highest percentage of wrong answers (30%), whereas Google had the lowest percentage (18%). All resources had a significant number of questions that they were unable to answer. Though hardcopy books have not been completely replaced by electronic resources, more than half of medical students and nearly half of residents prefer web-based sources of information. For quick questions and studying, both groups prefer Internet sources. However, the most commonly used electronic resources fail to answer clinical queries more than half

Electrochemical synthesis, in situ spectroelectrochemistry of conducting indole-titanium dioxide and zinc oxide polymer nanocomposites for rechargeable batteries

International Nuclear Information System (INIS)

Parvin, Mohammad Hadi; Pirnia, Mahsa; Arjomandi, Jalal

2015-01-01

Highlights: • Two novel hybrid materials-based conducting PIn rechargeable batteries were developed. • The charge-discharging behavior of PIn-nanocomposite batteries were studied. • The characterization of samples has been done by in situ spectroelectrochemical method. • PIn-TiO 2 and ZnO nanocomposites were synthesized electrochemically on Au and ITO. • The PIn-TiO 2 and ZnO nanocomposites resistances were less than PIn. - Abstract: Electrochemical synthesis, in situ spectroelectrochemistry of conducting polyindole (PIn), polyindole-TiO 2 (PIn-TiO 2 ) and polyindole-ZnO (PIn-ZnO) nanocomposites were investigated. The PIn and polymer nanocomposites were tested electrochemically for rechargeable batteries. The films were characterized by means of CVs, in situ UV-visible, FT-IR spectroscopies, in situ resistivity measurements, energy dispersive X-ray (EDX), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The charge-discharging behavior of a Zn/1 M ZnSO 4 /PIn cell with a capacity of around 90 Ah Kg −1 and on open circuit potential of around 1.45 V was compared with Zn/1 M ZnSO 4 /PIn-nanocomposite. The potential differences of redox couples (ΔE) for nanocomposites films show very good reversibility. A positive shift of potential was observed for polymer nanocomposites during redox scan. A significant variability was observed for in situ conductivity of the PIn and polymer nanocomposites. During in situ UV-visible and FT-IR measurements, intermediate spectroscopic behavior and positive shifts of wavelengths were observed for PIn and polymer nanocomposites. The SEM, TEM and EDX of nanocomposite films show the presence of nano particle in PIn.

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.

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.

Facile synthesis, dielectric properties and electrocatalytic activities of PMMA-NiFe{sub 2}O{sub 4} nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Maji, Pranabi; Choudhary, Ram Bilash, E-mail: rbcism@gmail.com

2017-06-01

The paper deals with the dielectric and catalytic properties of poly (methyl methacrylate)-nikel ferrite (PMMA-NiFe{sub 2}O{sub 4}) nanocomposite. The nanocomposite was prepared by using a general and facile synthesis strategy. Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectra confirmed the formation of PMMA-NiFe{sub 2}O{sub 4} nanocomposite. Field effect scanning electron microscopic (FESEM) and transmission electron microscopic (TEM) images revealed that NiFe{sub 2}O{sub 4} nanoparticles were uniformly distributed and were tightly adhered with PMMA matrix owing to surface modification with 3-methacryloyloxy propyl trimethoxy silane (KH-570). Thermal stability was enhanced by incorporation of NiFe{sub 2}O{sub 4} nanofillers. The nanocomposite showed high dielectric constant and low dielectric loss. The achieved dielectric and thermal property inferred the potential application of this material in energy storage and embedded electronics devices. Further, the as prepared nanocomposite also offered a remarkable electrochemical performance towards hydrogen peroxide (H{sub 2}O{sub 2}) sensing. - Highlights: • PMMA-NiFe{sub 2}O{sub 4} nanocomposite was synthesized via free radical polymerization. • The nanocomposite exhibited high value of dielectric constant (51) and tanδ (0.3). • Thermal stability of the PMMA matrix was improved by the incorporation of NiFe{sub 2}O{sub 4.} • The H{sub 2}O{sub 2} detection limit was estimated 44 μM when signal to noise (S/N) ration was 3. • The electrochemical sensitivity of H{sub 2}O{sub 2} was calculated 0.6727 μA mM{sup -1}.

Environmental Degradation and Durability of Epoxy-Clay Nanocomposites

Directory of Open Access Journals (Sweden)

Raman P. Singh

2010-01-01

Full Text Available This experimental investigation reports on the durability of epoxy-clay nanocomposites upon exposure to multiple environments. Nanocomposites are fabricated by mixing the clay particles using various combinations of mechanical mixing, high-shear dispersion, and ultrasonication. Clay morphology is characterized using X-ray diffraction and transmission electron microscopy. Specimens of both neat epoxy and the epoxy-clay nanocomposite are subjected to two environmental conditions: combined UV radiation and condensation on 3-hour repeat cycle and constant temperature-humidity, for a total exposure duration of 4770 hours. The presence of nanoscale clay inhibits moisture uptake, as demonstrated by exposure to constant temperature-humidity. Nonetheless, both materials lose mass under exposure to combined UV radiation and condensation due to the erosion of epoxy by a synergistic process. Surprisingly, the epoxy-clay specimens exhibit greater mass loss, as compared to neat epoxy. Mechanical testing shows that either environment does not significant affect the flexure modulus of either material. On the other hand, both materials undergo degradation in flexural strength when exposed to either environment. However, the epoxy-clay nanocomposite retains 37% more flexure strength than the neat epoxy after 4072 hours of exposure.

Facile solvothermal synthesis of graphene-MnOOH nanocomposites

International Nuclear Information System (INIS)

Chen Sheng; Zhu Junwu; Huang Huajie; Zeng Guiyu; Nie Fude; Wang Xin

2010-01-01

In this paper, we report a facile solvothermal route capable of aligning MnOOH nanocrystals on graphene. X-ray diffraction (XRD) and transmission electron microscopy (TEM) observations indicate that the exfoliated graphene sheets are decorated randomly by MnOOH nanocrystals, forming well-dispersed graphene-MnOOH nanocomposites. Dissolution-crystallization and oriented attachment are speculated to be the vital mechanisms in the synthetic process. The attachment of additives, such as MnOOH nanoparticles, are found to be beneficial for the exfoliation of GO as well as preventing the restack of graphene sheets. Moreover, cyclic voltammetry (CV) analyses suggest that the electrochemical reversibility is improved by anchoring MnOOH on graphene. Notably, the as-fabricated nanocomposites reveal unusual catalytic performance for the thermal decomposition of ammonium perchlorate (AP) due to the concerted effects of graphene and MnOOH. This template-free method is easy to reproduce, and the process proceeds at a low temperature and can be readily extended to prepare other graphene-based nanocomposites. - Graphical abstract: Manganese oxyhydroxide nanocrystals have been successfully attached onto the graphene sheets via an oriented attachment and dissolution-crystallization process, forming a nanocomposite with unusual catalytic capabilities. Display Omitted

Te/C nanocomposites for Li-Te Secondary Batteries

Science.gov (United States)

Seo, Jeong-Uk; Seong, Gun-Kyu; Park, Cheol-Min

2015-01-01

New battery systems having high energy density are actively being researched in order to satisfy the rapidly developing market for longer-lasting mobile electronics and hybrid electric vehicles. Here, we report a new Li-Te secondary battery system with a redox potential of ~1.7 V (vs. Li+/Li) adapted on a Li metal anode and an advanced Te/C nanocomposite cathode. Using a simple concept of transforming TeO2 into nanocrystalline Te by mechanical reduction, we designed an advanced, mechanically reduced Te/C nanocomposite electrode material with high energy density (initial discharge/charge: 1088/740 mA h cm-3), excellent cyclability (ca. 705 mA h cm-3 over 100 cycles), and fast rate capability (ca. 550 mA h cm-3 at 5C rate). The mechanically reduced Te/C nanocomposite electrodes were found to be suitable for use as either the cathode in Li-Te secondary batteries or a high-potential anode in rechargeable Li-ion batteries. We firmly believe that the mechanically reduced Te/C nanocomposite constitutes a breakthrough for the realization and mass production of excellent energy storage systems.

Environmental Degradation and Durability of Epoxy-Clay Nanocomposites

International Nuclear Information System (INIS)

Singh, R.P.; Zunjarrao, S.C.; Pandey, G.; Khait, M.; Korach, C.S.

2010-01-01

This experimental investigation reports on the durability of epoxy-clay nanocomposites upon exposure to multiple environments. Nanocomposites are fabricated by mixing the clay particles using various combinations of mechanical mixing, high-shear dispersion, and ultrasonication. Clay morphology is characterized using X-ray diffraction and transmission electron microscopy. Specimens of both neat epoxy and the epoxy-clay nanocomposite are subjected to two environmental conditions: combined UV radiation and condensation on 3-hour repeat cycle and constant temperature-humidity, for a total exposure duration of 4770 hours. The presence of nanoscale clay inhibits moisture uptake, as demonstrated by exposure to constant temperature-humidity. Nonetheless, both materials lose mass under exposure to combined UV radiation and condensation due to the erosion of epoxy by a synergistic process. Surprisingly, the epoxy-clay specimens exhibit greater mass loss, as compared to neat epoxy. Mechanical testing shows that either environment does not significant affect the flexure modulus of either material. On the other hand, both materials undergo degradation in flexural strength when exposed to either environment. However, the epoxy-clay nanocomposite retains 37% more flexure strength than the neat epoxy after 4072 hours of exposure.

Self-sensing performance of MWCNT-low density polyethylene nanocomposites

Science.gov (United States)

Gupta, Tejendra K.; Kumar, S.; Khan, Amal Z.; Varadarajan, Kartik M.; Cantwell, Wesley J.

2018-01-01

Carbon nanotubes (CNTs) based polymer nanocomposites offer a range of remarkable properties. Here, we demonstrate self-sensing performance of low density polyethylene (LDPE)-multiwalled carbon nanotubes (MWCNTs) nanocomposites for the first time. The dispersion of the CNTs and the morphology of the nanocomposites was investigated using scanning electron microscopy, x-ray diffraction and Raman spectroscopic techniques. The thermal properties were measured using thermal gravimetric analysis and differential scanning calorimetry and were found to increase with increasing wt% of MWCNTs in LDPE matrix. An overall improvement in ultimate tensile strength, yield strength and Young’s modulus was found to be 59.6%, 48.5% and 129.3%, respectively for 5.0 wt% loading of MWCNTs. The electrical percolation threshold was observed at 1.0 wt% of MWCNTs and the highest electrical conductivity of 2.8 × 10-2 Scm-1 was observed at 5.0 wt% loading of MWCNTs. These piezo-resistive nanocomposites offer tunable self-sensing capabilities with gauge factors in the ranges of 17-52 and 42-530 in linear elastic (strain ˜3%) and inelastic regimes (strain ˜15%) respectively. Our demonstration would provide guidelines for the fabrication of low cost, self-sensing MWCNT-LDPE nanocomposites for potential use as civil water pipelines and landfill membranes.

Preparation and properties of multifunctional Fe-C-Y2O3:Eu3+ nanocomposites

International Nuclear Information System (INIS)

Yang Jingxing; Yang Xuwei; Yang Hua

2012-01-01

Highlights: ► Multifunctional Fe/Fe 3 O 4 -Y 2 O 3 : Eu nanocomposites were prepared by a solvothermal method. ► Their structure, magnetic and luminescent properties were characterized by XRD, SEM, TEM, excitation and emission spectra and vibration sample magnetometry (VSM). ► It is shown that the nanocomposites exhibit high saturation magnetization and strong red emission under UV-light. - Abstract: Multifunctional Fe-C-Y 2 O 3 :Eu 3+ nanocomposites were prepared by the solvo thermal method, and their structure, magnetic and luminescent properties were characterized by X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and scanning electron microscope (SEM). Results show that the nanocomposites are spherical with a mean diameter of 700 nm and there are high special saturation magnetization (47.4 emu/g) and strong red emission under UV-light. Even dispersed in water solution, the nanocomposites also exhibit a strong red emission under ultraviolet light radiation, and it could be manipulated using an external magnet. Thus it looks promising for application in biomedicine field, especially in drug targeting and fluorescence label. And we also discussed the effect of the electron transfer process between the Fe magnetic core and Y 2 O 3 :Eu 3+ shell.

Synthesis of NiO@MnO{sub 2} core/shell nanocomposites for supercapacitor application

Energy Technology Data Exchange (ETDEWEB)

Chen, Junjiao; Huang, Ying, E-mail: chenjunjiao001@163.com; Li, Chao; Chen, Xuefang; Zhang, Xiang

2016-01-01

Graphical abstract: - Highlights: • MnO{sub 2} nanosheets were grown on the surface of porous NiO microtube. • The NiO@MnO{sub 2} nanocomposite exhibits excellent cycle performance. • The nanocomposite exhibits specific capacitance of 266.7 F g{sup −1} at 0.5 A g{sup −1}. - Abstract: In this work, NiO@MnO{sub 2} core/shell nanocomposites were fabricated by a two-step method. The morphology and structure of the nanocomposites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction analysis and thermal gravity analysis. In addition, the supercapacitive performances were examined by cyclic voltammogram (CV), galvanostatic charge–discharge and electrochemical impedance spectroscopy (EIS). The electrochemical results indicate that the composite exhibits a specific capacitance of 266.7 F g{sup −1} at 0.5 A g{sup −1} and excellent cycling stability (81.7% retention after 2000 cycles at 1 A g{sup −1}). Therefore, this wok offers meaningful reference for supercpacitor applications in the future.

One-pot synthesis and transfer of PMMA/Ag photonic nanocomposites by pulsed laser deposition

Science.gov (United States)

Karoutsos, V.; Koutselas, I.; Orfanou, P.; Mpatzaka, Th.; Vasileiadis, M.; Vassilakopoulou, A.; Vainos, N. A.; Perrone, A.

2015-08-01

Nanocomposite films comprising metallic nanoparticles in polymer matrices find increasing use in emerging photonic, electronic and microsystem applications owing to their tailored advanced functionalities. The versatile development of such films based on poly-methyl-methacrylate (PMMA) matrix having embedded Ag nanoparticles is addressed here. Two low-cost one-pot chemical methods for the synthesis of bulk target nanocomposite materials are demonstrated. These nanocomposites are subsequently transferred via pulsed laser deposition using 193 nm ArF excimer laser radiation, producing films maintaining the structural and functional properties. Both target- and laser-deposited materials have been thoroughly characterized using microscopic, spectroscopic and thermal analysis methods. Infrared spectra demonstrated the close molecular PMMA chain similarity for both target and film materials, though structural alterations identified by thermal analysis proved the enhanced characteristics of films grown. High-resolution electron microscopy proved the transfer of Ag nanoparticles sized 10-50 nm. Visible absorption peaked in the spectral range of 430-440 nm and attributed to the Ag nanocomposite plasmonic response verifying the transfer of the functional performance from target to film.

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.

Bulk Heterojunction Solar Cell with Nitrogen-Doped Carbon Nanotubes in the Active Layer: Effect of Nanocomposite Synthesis Technique on Photovoltaic Properties

Directory of Open Access Journals (Sweden)

Godfrey Keru

2015-05-01

Full Text Available Nanocomposites of poly(3-hexylthiophene (P3HT and nitrogen-doped carbon nanotubes (N-CNTs have been synthesized by two methods; specifically, direct solution mixing and in situ polymerization. The nanocomposites were characterized by means of transmission electron microscopy (TEM, scanning electron microscopy (SEM, X-ray dispersive spectroscopy, UV-Vis spectrophotometry, photoluminescence spectrophotometry (PL, Fourier transform infrared spectroscopy (FTIR, Raman spectroscopy, thermogravimetric analysis, and dispersive surface energy analysis. The nanocomposites were used in the active layer of a bulk heterojunction organic solar cell with the composition ITO/PEDOT:PSS/P3HT:N-CNTS:PCBM/LiF/Al. TEM and SEM analysis showed that the polymer successfully wrapped the N-CNTs. FTIR results indicated good π-π interaction within the nanocomposite synthesized by in situ polymerization as opposed to samples made by direct solution mixing. Dispersive surface energies of the N-CNTs and nanocomposites supported the fact that polymer covered the N-CNTs well. J-V analysis show that good devices were formed from the two nanocomposites, however, the in situ polymerization nanocomposite showed better photovoltaic characteristics.

Antimicrobial and Controlled Release Studies of a Novel Nystatin Conjugated Iron Oxide Nanocomposite

Directory of Open Access Journals (Sweden)

Samer Hasan Hussein-Al-Ali

2014-01-01

Full Text Available Nystatin is a tetraene diene polyene antibiotic showing a broad spectrum of antifungal activity. In the present study, we prepared a nystatin nanocomposite (Nyst-CS-MNP by loading nystatin (Nyst on chitosan (CS coated magnetic nanoparticles (MNPs. The magnetic nanocomposites were characterized by X-ray powder diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, thermogravimetry analysis (TGA, vibrating sample magnetometer (VSM, and scanning electron microscopy (SEM. The XRD results showed that the MNPs and nanocomposite are pure magnetite. The FTIR analysis confirmed the binding of CS on the surface of the MNPs and also the loading of Nyst in the nanocomposite. The Nyst drug loading was estimated using UV-Vis instrumentation and showing a 14.9% loading in the nanocomposite. The TEM size image of the MNPs, CS-MNP, and Nyst-CS-MNP was 13, 11, and 8 nm, respectively. The release profile of the Nyst drug from the nanocomposite followed a pseudo-second-order kinetic model. The antimicrobial activity of the as-synthesized Nyst and Nyst-CS-MNP nanocomposite was evaluated using an agar diffusion method and showed enhanced antifungal activity against Candida albicans. In this manner, this study introduces a novel nanocomposite that can decrease fungus activity on-demand for numerous medical applications.

Preparation and characterization of sepiolite-based phase change material nanocomposites for thermal energy storage

International Nuclear Information System (INIS)

Konuklu, Yeliz; Ersoy, Orkun

2016-01-01

Highlights: • Sepiolite-based phase change material nanocomposites were prepared. • An easy direct impregnation process was used. • This paper is one of the first study about sepiolite-based phase change material nanocomposites. • Influence of PCM type on thermal properties of nanocomposites was reported. - Abstract: This paper is one of the first study about the preparation and characterization of sepiolite-based phase change material nanocomposites for thermal energy storage applications. Sepiolite is an important natural fibrous raw material. Nanoscale fibrous tubular structure of sepiolite becomes important in nanocomposite preparation. In this study, sepiolite/paraffin and sepiolite/decanoic acid nanocomposites were manufactured by the direct impregnation method. By the preparation of nanocomposites, PCM move in tubular channels of sepiolite, phase changing occurs in these tubes and surface area increases like as in microencapsulation. The structure and properties of nanocomposites PCMs (CPCM) have been characterized via scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The SEM results prove the successful preparation of phase change material/sepiolite nanocomposites and point out that the fibers of sepiolite is modified with phase change materials in the nanocomposite. The phase change enthalpies of melting and freezing were about 62.08 J/g and −62.05 J/g for sepiolite/paraffin nanocomposites and 35.69 J/g and −34.55 J/g for sepiolite/decanoic acid nanocomposites, respectively. The results show that PCM/sepiolite nanocomposites were prepared successfully and their properties are very suitable for thermal energy storage applications.

CdS/ZnS nanocomposites: from mechanochemical synthesis to cytotoxicity issues

International Nuclear Information System (INIS)

Baláž, Peter; Baláž, Matej; Dutková, Erika; Zorkovská, Anna; Kováč, Jaroslav; Hronec, Pavol; Kováč, Jaroslav; Čaplovičová, Mária; Mojžiš, Ján; Mojžišová, Gabriela; Eliyas, Alexander; Kostova, Nina G.

2016-01-01

CdS/ZnS nanocomposites have been prepared by a two-step solid-state mechanochemical synthesis. CdS has been prepared from cadmium acetate and sodium sulfide precursors in the first step. The obtained cubic CdS (hawleyite, JCPDS 00-010-0454) was then mixed in the second step with the cubic ZnS (sphalerite, JCPDS 00-005-0566) synthesized mechanochemically from the analogous precursors. The crystallite sizes of the new type CdS/ZnS nanocomposite, calculated based on the XRD data, were 3–4 nm for both phases. The synthesized nanoparticles have been further characterized by high-resolution transmission electron microscopy (HRTEM) and micro-photoluminescence (μPL) spectroscopy. The PL emission peaks in the PL spectra are attributed to the recombination of holes/electrons in the nanocomposites occurring in depth associated with Cd, Zn vacancies and S interstitials. Their photocatalytic activity was also measured. In the photocatalytic activity tests to decolorize Methyl Orange dye aqueous solution, the process is faster and its effectivity is higher when using CdS/ZnS nanocomposite, compared to single phase CdS. Very low cytotoxic activity (high viability) of the cancer cell lines (selected as models of living cells) has been evidenced for CdS/ZnS in comparison with CdS alone. This fact is in a close relationship with Cd(II) ions dissolution tested in a physiological solution. The concentration of cadmium dissolved from CdS/ZnS nanocomposites with variable Cd:Zn ratio was 2.5–5.0 μg.mL"−"1, whereas the concentration for pure CdS was much higher — 53 μg.ml"−"1. The presence of ZnS in the nanocrystalline composite strongly reduced the release of cadmium into the physiological solution, which simulated the environment in the human body. The obtained CdS/ZnS quantum dots can serve as labeling media and co-agents in future anti-cancer drugs, because of their potential in theranostic applications. - Highlights: • CdS/ZnS nanocomposites with crystallite size 3–4

CdS/ZnS nanocomposites: from mechanochemical synthesis to cytotoxicity issues

Energy Technology Data Exchange (ETDEWEB)

Baláž, Peter; Baláž, Matej [Institute of Geotechnics, Slovak Academy of Sciences, 04001 Košice (Slovakia); Dutková, Erika, E-mail: dutkova@saske.sk [Institute of Geotechnics, Slovak Academy of Sciences, 04001 Košice (Slovakia); Zorkovská, Anna [Institute of Geotechnics, Slovak Academy of Sciences, 04001 Košice (Slovakia); Kováč, Jaroslav; Hronec, Pavol; Kováč, Jaroslav [Institute of Electronics and Photonics, Slovak University of Technology and International Laser Centre, 81219 Bratislava (Slovakia); Čaplovičová, Mária [STU Centre for Nanodiagnostics, Slovak University of Technology, Vazovova 5, 812 43 Bratislava (Slovakia); Mojžiš, Ján; Mojžišová, Gabriela [Faculty of Medicine, P. J. Šafárik University, 04011 Košice (Slovakia); Eliyas, Alexander; Kostova, Nina G. [Institute of Catalysis, Bulgarian Academy of Sciences, 1113 Sofia (Bulgaria)

2016-01-01

CdS/ZnS nanocomposites have been prepared by a two-step solid-state mechanochemical synthesis. CdS has been prepared from cadmium acetate and sodium sulfide precursors in the first step. The obtained cubic CdS (hawleyite, JCPDS 00-010-0454) was then mixed in the second step with the cubic ZnS (sphalerite, JCPDS 00-005-0566) synthesized mechanochemically from the analogous precursors. The crystallite sizes of the new type CdS/ZnS nanocomposite, calculated based on the XRD data, were 3–4 nm for both phases. The synthesized nanoparticles have been further characterized by high-resolution transmission electron microscopy (HRTEM) and micro-photoluminescence (μPL) spectroscopy. The PL emission peaks in the PL spectra are attributed to the recombination of holes/electrons in the nanocomposites occurring in depth associated with Cd, Zn vacancies and S interstitials. Their photocatalytic activity was also measured. In the photocatalytic activity tests to decolorize Methyl Orange dye aqueous solution, the process is faster and its effectivity is higher when using CdS/ZnS nanocomposite, compared to single phase CdS. Very low cytotoxic activity (high viability) of the cancer cell lines (selected as models of living cells) has been evidenced for CdS/ZnS in comparison with CdS alone. This fact is in a close relationship with Cd(II) ions dissolution tested in a physiological solution. The concentration of cadmium dissolved from CdS/ZnS nanocomposites with variable Cd:Zn ratio was 2.5–5.0 μg.mL{sup −1}, whereas the concentration for pure CdS was much higher — 53 μg.ml{sup −1}. The presence of ZnS in the nanocrystalline composite strongly reduced the release of cadmium into the physiological solution, which simulated the environment in the human body. The obtained CdS/ZnS quantum dots can serve as labeling media and co-agents in future anti-cancer drugs, because of their potential in theranostic applications. - Highlights: • CdS/ZnS nanocomposites with crystallite

Physical, Mechanical, Thermal and Morphology Properties of Biodegradable Polymer Nanocomposites and Its Comparison

Directory of Open Access Journals (Sweden)

Rahman Md. Rezaur

2017-01-01

Full Text Available Polyvinyl alcohol (PVA and Polylactic acid (PLA were fabricated with the addition of nanofiller such as nanoclay and fumed silica through suitable technique namely solution intercalation film casting. These nanocomposites undergo Fourier transform infrared spectroscopy, scanning electron microscopy, tensile test and thermogravimetric analysis. FT-IR results showed that both nanocomposites were well intercalated with fumed silica and clay with the reduction of hydroxyl groups. From SEM results, it proved that clay 1.28E is more suitable to be intercalated with PLA matrix while clay 1.30E is more suitable to be introduced into PVA matrix. The addition of both nanofillers improved the tensile properties of the nanocomposites. TGA results showed that polyvinyl alcohol/fumed silica/clay (PVA/fsi/clay had better thermal stability compared to polylactic acid/fumed silica/clay (PLA/fsi/clay nanocomposites. Both nanocomposites are applicable in the biomedical field.

GRAPHENE BASED METAL AND METAL OXIDE NANOCOMPOSITES: SYNTHESIS, PROPERTIES AND THEIR APPLICATIONS

KAUST Repository

Khan, Mujeeb; Tahir, Muhammad Nawaz; Adil, Syed F; Khan, Hadayat Ullah; Siddiqui, Rafiq H; Al-Warthan, Abdulrahman Abdullah; Tremel, Wolfgang

2015-01-01

Graphene, an atomically thin two-dimensional carbonaceous material, has attracted tremendous attention in the scientific community, due to its exceptional electronic, electrical, and mechanical properties. Indeed, with the recent explosion of methods for a large-scale synthesis of graphene, the number of publications related to graphene and other graphene based materials have increased exponentially. Particularly the easy preparation of graphene like materials, such as, highly reduced graphene oxide (HRG) via reduction of graphite oxide (GO), offers a wide range of possibilities for the preparation of graphene based inorganic nanocomposites by the incorporation of various functional nanomaterials for a variety of applications. In this review, we discuss the current development of graphene based metal and metal oxide nanocomposites, with a detailed account of their synthesis and properties. Specifically, much attention has been given to their wide range of applications in various fields, including, electronics, electrochemical and electrical fields. Overall, by the inclusion of various references, this review covers in detail aspects of the graphene-based inorganic nanocomposites.

GRAPHENE BASED METAL AND METAL OXIDE NANOCOMPOSITES: SYNTHESIS, PROPERTIES AND THEIR APPLICATIONS

KAUST Repository

Khan, Mujeeb

2015-06-11

Graphene, an atomically thin two-dimensional carbonaceous material, has attracted tremendous attention in the scientific community, due to its exceptional electronic, electrical, and mechanical properties. Indeed, with the recent explosion of methods for a large-scale synthesis of graphene, the number of publications related to graphene and other graphene based materials have increased exponentially. Particularly the easy preparation of graphene like materials, such as, highly reduced graphene oxide (HRG) via reduction of graphite oxide (GO), offers a wide range of possibilities for the preparation of graphene based inorganic nanocomposites by the incorporation of various functional nanomaterials for a variety of applications. In this review, we discuss the current development of graphene based metal and metal oxide nanocomposites, with a detailed account of their synthesis and properties. Specifically, much attention has been given to their wide range of applications in various fields, including, electronics, electrochemical and electrical fields. Overall, by the inclusion of various references, this review covers in detail aspects of the graphene-based inorganic nanocomposites.

Antimicrobial hyperbranched poly(ester amide)/polyaniline nanofiber modified montmorillonite nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Pramanik, Sujata [Advanced Polymer and Nanomaterial Laboratory, Department of Chemical Sciences, Tezpur University, Tezpur 784028 (India); Bharali, Pranjal; Konwar, B.K. [Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028 (India); Karak, Niranjan, E-mail: karakniranjan@yahoo.com [Advanced Polymer and Nanomaterial Laboratory, Department of Chemical Sciences, Tezpur University, Tezpur 784028 (India)

2014-02-01

There has been growing interest in the use of nanomaterials featuring potent of antimicrobial activity in the biomedical domain. It still remains a challenge for the researchers to develop an efficient nanocomposite possessing antimicrobial efficacy against broad spectrum microbes including bacteria, fungi as well as algal consortium, posing serious challenges for the human survival. In addressing the above problem, we report the fabrication of bio-based hyperbranched poly(ester amide) (HBPEA)/polyaniline nanofiber modified montmorillonite (MMT) nanocomposites by an ex-situ polymerization technique at varied weight percentages (1, 2.5, 5 wt.%) of the modified MMT (nanohybrid). The Fourier transform infrared spectroscopy confirmed the structural changes upon interaction of the nanohybrid with HBPEA. A probable mechanism is proposed for the formation of nanocomposites with partially exfoliated nanoplatelet structure, which was further confirmed from the high resolution transmission electron microscopic analyses. The prepared nanocomposites exhibited potent efficacy against gram positive bacteria like Bacillus subtilis and Staphylococcus aureus as compared to the gram negative ones like Pseudomonas aeruginosa and Escherichia coli. The nanocomposites showed significant antifungal activity against Aspergillus niger, Fusarium oxysporum and Coleotricum capcii and antialgal activity against algal consortium comprising of Chlorella, Hormidium and Cladophorella species. The formation of thermosetting nanocomposites resulted in the acceptable improvement of desired physico-chemical and mechanical properties including thermostability. Thus pronounced antimicrobial activity of the nanocomposites against a spectrum of bacterial and fungal strains as well as a consortium of algal species along with other desired performance vouched them as potent antimicrobial materials in the realm of health and biomedical industry. - Highlights: • A possible approach for fabrication of the

Antimicrobial hyperbranched poly(ester amide)/polyaniline nanofiber modified montmorillonite nanocomposites

International Nuclear Information System (INIS)

Pramanik, Sujata; Bharali, Pranjal; Konwar, B.K.; Karak, Niranjan

2014-01-01

There has been growing interest in the use of nanomaterials featuring potent of antimicrobial activity in the biomedical domain. It still remains a challenge for the researchers to develop an efficient nanocomposite possessing antimicrobial efficacy against broad spectrum microbes including bacteria, fungi as well as algal consortium, posing serious challenges for the human survival. In addressing the above problem, we report the fabrication of bio-based hyperbranched poly(ester amide) (HBPEA)/polyaniline nanofiber modified montmorillonite (MMT) nanocomposites by an ex-situ polymerization technique at varied weight percentages (1, 2.5, 5 wt.%) of the modified MMT (nanohybrid). The Fourier transform infrared spectroscopy confirmed the structural changes upon interaction of the nanohybrid with HBPEA. A probable mechanism is proposed for the formation of nanocomposites with partially exfoliated nanoplatelet structure, which was further confirmed from the high resolution transmission electron microscopic analyses. The prepared nanocomposites exhibited potent efficacy against gram positive bacteria like Bacillus subtilis and Staphylococcus aureus as compared to the gram negative ones like Pseudomonas aeruginosa and Escherichia coli. The nanocomposites showed significant antifungal activity against Aspergillus niger, Fusarium oxysporum and Coleotricum capcii and antialgal activity against algal consortium comprising of Chlorella, Hormidium and Cladophorella species. The formation of thermosetting nanocomposites resulted in the acceptable improvement of desired physico-chemical and mechanical properties including thermostability. Thus pronounced antimicrobial activity of the nanocomposites against a spectrum of bacterial and fungal strains as well as a consortium of algal species along with other desired performance vouched them as potent antimicrobial materials in the realm of health and biomedical industry. - Highlights: • A possible approach for fabrication of the

Dynamic mechanical analysis of single walled carbon nanotubes/polymethyl methacrylate nanocomposite films

International Nuclear Information System (INIS)

Badawi, Ali; Al Hosiny, N.

2015-01-01

Dynamic mechanical properties of nanocomposite films with different ratios of single walled carbon nanotubes/polymethyl methacrylate (SWCNTs/PMMA) are studied. Nanocomposite films of different ratios (0, 0.5, 1.0, and 2.0 weight percent (wt%)) of SWCNTs/PMMA are fabricated by using a casting technique. The morphological and structural properties of both SWCNT powder and SWCNTs/PMMA nanocomposite films are investigated by using a high resolution transmission electron microscope and x-ray diffractometer respectively. The mechanical properties including the storage modulus, loss modulus, loss factor (tan δ) and stiffness of the nanocomposite film as a function of temperature are recorded by using a dynamic mechanical analyzer at a frequency of 1 Hz. Compared with pure PMMA film, the nanocomposite films with different ratios of SWCNTs/PMMA are observed to have enhanced storage moduli, loss moduli and high stiffness, each of which is a function of temperature. The intensity of the tan δ peak for pure PMMA film is larger than those of the nanocomposite films. The glass transition temperature (T g ) of SWCNTs/PMMA nanocomposite film shifts towards the higher temperature side with respect to pure PMMA film from 91.2 °C to 99.5 °C as the ratio of SWCNTs/PMMA increases from 0 to 2.0 wt%. (paper)

Thermal properties of oil palm nano filler/kenaf reinforced epoxy hybrid nanocomposites

Science.gov (United States)

Saba, N.; Paridah, M. T.; Abdan, K.; Ibrahim, N. A.

2016-11-01

The aim of this research study was to fabricate nano oil palm empty fruit bunch (OPEFB)/kenaf/epoxy hybrid nanocomposites and to make comparative study on the thermal properties of nano OPEFB/kenaf/epoxy hybrid nanocomposites with the montmorillonite (MMT)/kenaf/epoxy hybrid nanocomposites and organically modified MMT (OMMT)/kenaf/epoxy hybrid nanocomposites. Epoxy based kenaf hybrid nanocomposites was prepared by dispersing the nano filler (nano OPEFB filler, MMT, OMMT) at 3% loading through high speed mechanical stirrer followed by hand lay-up technique. Thermal properties of hybrid nanocomposites were analyzed through thermogravimetry analyzer (TGA), and differential scanning calorimetry (DSC). Obtained results specified that addition of nano OPEFB filler improves the thermal stability and char yield of kenaf/epoxy composites. Furthermore, the increase in decomposition temperature by the nano OPEFB filler was quite comparable to the MMT/kenaf/epoxy but relatively less than OMMT/kenaf/epoxy hybrid nanocomposites. We concluded from overall consequences that the nano OPEFB filler can be used as the promising and innovative alternative of existing expensive nano filler, with relatively lesser impact on the environment having marked pronounced impact on the construction, automotive, aerospace, electronics and semiconducting sectors as future industries based on bio-wastes with satisfactory light weight and thermal stability on other side.

Temperature responsive hydrogel magnetic nanocomposites for hyperthermia and metal extraction applications

Energy Technology Data Exchange (ETDEWEB)

Reddy, N. Narayana, E-mail: nagireddynarayana@gmail.com [Center for Advanced Biomaterials for Healthcare, Istituto Italiano di Tecnologia@CRIB, Largo Barsanti e Matteucci 53, 80125 Napoli (Italy); Ravindra, S. [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg 1709 (South Africa); Reddy, N. Madhava [Department of Environmental Science, Gates Institute of Technology, NH-7, Gooty, Anantapuram, Andhra Pradesh (India); Rajinikanth, V. [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg 1709 (South Africa); Raju, K. Mohana [Synthetic Polymer Laboratory, Department of Polymer Science & Technology, S.K. University, Anantapuram, Andhra Pradesh (India); Vallabhapurapu, Vijaya Srinivasu [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Johannesburg 1709 (South Africa)

2015-11-15

The present work deals with the development of temperature and magnetic responsive hydrogel networks based on poly (N-isopropylacrylamide)/acrylamido propane sulfonic acid. The hydrogel matrices are synthesized by polymerizing N-isopropylacrylamide (NIPAM) monomer in the presence of acrylamido propane sulphonicacid (AMPS) using a cross-linker (N,N-methylenebisacrylamide, MBA) and redox initiating system [ammonium persulphate (APS)/tetramethylethylenediamine (TMEDA)]. The magnetic nanoparticles are generated throughout the hydrogel networks using in situ method by incorporating iron ions and subsequent treatment with ammonia. A series of hydrogel-magnetic nanocomposites (HGMNC) are developed by varying AMPS composition. The synthesized hydrogel magnetic nanocomposites (HGMNC) are characterized by using Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), Thermal Analyses and Electron Microscopy analysis (Scanning and Transmission Electron Microscope). The metal extraction capacities of the prepared hydrogel (HG) and hydrogel magnetic nanocomposites (HGMNC) were studied at different temperatures. The results suggest that HGMNCs have higher extraction capacity compared to HG and HG loaded iron ions. This data also reveals that the extraction of metals by hydrogel magnetic nanocomposites (HGMNCs) is higher at higher temperatures than room temperature. The prepared HGMNCs are also subjected to hyperthermia (cancer therapy) studies. - Highlights: • We have developed temperature responsive hydrogel magnetic nanocomposites. • Addition of AMPS monomer to this magnetic hydrogel enhances the temperature sensitivity to 40–43 °C. • Similarly the sulfonic groups present in the AMPS units enhances the swelling ratio of magnetic hydrogels. • AMPS acts as good stabilizing agent for nanoparticles in the magnetic nanogel.

Temperature responsive hydrogel magnetic nanocomposites for hyperthermia and metal extraction applications

International Nuclear Information System (INIS)

Reddy, N. Narayana; Ravindra, S.; Reddy, N. Madhava; Rajinikanth, V.; Raju, K. Mohana; Vallabhapurapu, Vijaya Srinivasu

2015-01-01

The present work deals with the development of temperature and magnetic responsive hydrogel networks based on poly (N-isopropylacrylamide)/acrylamido propane sulfonic acid. The hydrogel matrices are synthesized by polymerizing N-isopropylacrylamide (NIPAM) monomer in the presence of acrylamido propane sulphonicacid (AMPS) using a cross-linker (N,N-methylenebisacrylamide, MBA) and redox initiating system [ammonium persulphate (APS)/tetramethylethylenediamine (TMEDA)]. The magnetic nanoparticles are generated throughout the hydrogel networks using in situ method by incorporating iron ions and subsequent treatment with ammonia. A series of hydrogel-magnetic nanocomposites (HGMNC) are developed by varying AMPS composition. The synthesized hydrogel magnetic nanocomposites (HGMNC) are characterized by using Fourier Transform Infrared (FTIR) Spectroscopy, X-ray diffraction (XRD), Thermal Analyses and Electron Microscopy analysis (Scanning and Transmission Electron Microscope). The metal extraction capacities of the prepared hydrogel (HG) and hydrogel magnetic nanocomposites (HGMNC) were studied at different temperatures. The results suggest that HGMNCs have higher extraction capacity compared to HG and HG loaded iron ions. This data also reveals that the extraction of metals by hydrogel magnetic nanocomposites (HGMNCs) is higher at higher temperatures than room temperature. The prepared HGMNCs are also subjected to hyperthermia (cancer therapy) studies. - Highlights: • We have developed temperature responsive hydrogel magnetic nanocomposites. • Addition of AMPS monomer to this magnetic hydrogel enhances the temperature sensitivity to 40–43 °C. • Similarly the sulfonic groups present in the AMPS units enhances the swelling ratio of magnetic hydrogels. • AMPS acts as good stabilizing agent for nanoparticles in the magnetic nanogel

Nanocomposite/Hybrid Materials of Electroactive Polymers With Inorganic Oxides for Biosensor Applications

National Research Council Canada - National Science Library

Wei, Yen

2001-01-01

As proposed, we have successfully synthesized new electroactive and electronically conductive polyaniline polymethacrylate-silica nanocomposites and fabricated biosensor devices, aimed for detecting...

Morphology, rheology and electrical resistivity of PLLA/HDPE/CNT nanocomposites: Effect of maleic anhydride

Energy Technology Data Exchange (ETDEWEB)

Shao, Li-na; Chen, Jie; Dai, Jian; Chen, Hai-ming; Yang, Jing-hui [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Wang, Yong, E-mail: yongwang1976@163.com [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Zhang, Chao-liang [State Key Laboratory of Oral Diseases, Sichuan University, Chengdu 610041 (China)

2015-02-15

As a part of serial work about tuning the selective location of carbon nanotubes (CNTs) in immiscible polymer blends, this work reports the effects of component polarity and viscosity ratio between components on the selective location of CNTs and the resultant electrical resistivity of the nanocomposites. To achieve the research aim, maleic anhydride (MA) was grafted onto poly(L-lactide) (PLLA) main chain through a reactive compounding processing. After that, different contents of CNTs were incorporated into blends of high density polyethylene (HDPE) and PLLA (or PLLA-g-MA). The morphologies of the ternary nanocomposites and the selective location of CNTs in the nanocomposites were characterized using scanning electron microscope (SEM) and transmission electron microscope (TEM). The microstructure of nanocomposites and the dispersion of CNTs were further proved by rheological measurement. Finally, the electrical resistivity of nanocomposites containing different CNT contents was measured. The results showed that through increasing the polarity of PLLA and decreasing the melt viscosity, CNTs were kinetically trapped at the blend interface region. Consequently, largely decreased percolation threshold was achieved for the PLLA-g-MA/HDPE/CNT nanocomposites. The morphological changes as well as the rheological properties were also comparatively analyzed. - Highlights: • PLLA/HDPE/CNT and PLLA-g-MA/HDPE/CNT composites were prepared. • Different selective location states of CNTs were achieved in different composites. • Selectively located CNTs at the interface resulted in lower percolation threshold.

Low-temperature solid-state synthesis and optical properties of ZnO/CdS nanocomposites

International Nuclear Information System (INIS)

Liu, Jinsong; Zhu, Kongjun; Sheng, Beibei; Li, Ziquan; Tai, Guoan; Qiu, Jinhao; Wang, Jing; Chen, Jiankang; You, Yuncheng; Gu, Qilin; Liu, Pengcheng

2015-01-01

Highlights: • Using a low-temperature solid-state method, ZnO/CdS nanocomposites were obtained • Grain growth kinetics of cubic CdS and hexagonal ZnO phase was described. • Sufficient grinding and heating treatment was a key for formation of composites. • Optical properties could be easily manipulated by reaction temperature and time. - Abstract: A simple low-temperature solid-state reaction in the presence of the surfactant PEG400 was developed to obtain ZnO/CdS nanocomposites. The effects of synthesis temperature and reaction time on crystal structure and optical properties of the nanocomposites were investigated by several technologies. X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM) characterizations showed that the products consisted of the nanoparticles, and the grain growth kinetics of the cubic CdS and the hexagonal ZnO phase in the nanocomposites was described. The mechanism analysis suggested that sufficient grinding and heating treatment was a key to form the ZnO/CdS nanocomposites, and the surfactant PEG400 was proved not to involve the reaction and prevent the nanoparticles from aggregating to larger in whole grinding and heat-treatment process. Ultraviolet–visible (UV–vis) spectra revealed that the band gaps of the nanocomposites could be tuned by the reaction temperature and reaction time. Photoluminescence (PL) spectra showed that the changing position and the intensity of the emission peaks resulted from the rate of electron transfer and recombination probability under the different conditions

DC bias effect on alternating current electrical conductivity of poly(ethylene terephthalate)/alumina nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Nikam, Pravin N., E-mail: pravinya26@gmail.com; Deshpande, Vineeta D., E-mail: drdeshpandevd@gmail.com [Department of Physics, Institute of Chemical Technology, Matunga, Mumbai-400019, Maharashtra (India)

2016-05-06

Polymer nanocomposites based on metal oxide (ceramic) nanoparticles are a new class of materials with unique properties and designed for various applications such as electronic device packaging, insulation, fabrication and automotive industries. Poly(ethylene terephthalate) (PET)/alumina (Al{sub 2}O{sub 3}) nanocomposites with filler content between 1 wt% and 5 wt% were prepared by melt compounding method using co-rotating twin screw extruder and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and precision LCR meter techniques. The results revealed that proper uniform dispersion at lower content up to 2 wt% of nano-alumina observed by using TEM. Aggregation of nanoparticles was observed at higher content of alumina examined by using SEM and TEM. The frequency dependences of the alternating current (AC) conductivity (σ{sub AC}) of PET/alumina nanocomposites on the filler content and DC bias were investigated in the frequency range of 20Hz - 1MHz. The results showed that the AC and direct current (DC) conductivity increases with increasing DC bias and nano-alumina content upto 3 wt%. It follows the Jonscher’s universal power law of solids. It revealed that σ{sub AC} of PET/alumina nanocomposites can be well characterized by the DC conductivity (σ{sub DC}), critical frequency (ω{sub c}), critical exponent of the power law (s). Roll of DC bias potential led to an increase of DC conductivity (σ{sub DC}) due to the creation of additional conducting paths with the polymer nanocomposites and percolation behavior achieved through co-continuous morphology.

DC bias effect on alternating current electrical conductivity of poly(ethylene terephthalate)/alumina nanocomposites

International Nuclear Information System (INIS)

Nikam, Pravin N.; Deshpande, Vineeta D.

2016-01-01

Polymer nanocomposites based on metal oxide (ceramic) nanoparticles are a new class of materials with unique properties and designed for various applications such as electronic device packaging, insulation, fabrication and automotive industries. Poly(ethylene terephthalate) (PET)/alumina (Al_2O_3) nanocomposites with filler content between 1 wt% and 5 wt% were prepared by melt compounding method using co-rotating twin screw extruder and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and precision LCR meter techniques. The results revealed that proper uniform dispersion at lower content up to 2 wt% of nano-alumina observed by using TEM. Aggregation of nanoparticles was observed at higher content of alumina examined by using SEM and TEM. The frequency dependences of the alternating current (AC) conductivity (σ_A_C) of PET/alumina nanocomposites on the filler content and DC bias were investigated in the frequency range of 20Hz - 1MHz. The results showed that the AC and direct current (DC) conductivity increases with increasing DC bias and nano-alumina content upto 3 wt%. It follows the Jonscher’s universal power law of solids. It revealed that σ_A_C of PET/alumina nanocomposites can be well characterized by the DC conductivity (σ_D_C), critical frequency (ω_c), critical exponent of the power law (s). Roll of DC bias potential led to an increase of DC conductivity (σ_D_C) due to the creation of additional conducting paths with the polymer nanocomposites and percolation behavior achieved through co-continuous morphology.

On the Injection Molding Processing Parameters of HDPE-TiO₂ Nanocomposites.

Science.gov (United States)

Mourad, Abdel-Hamid I; Mozumder, Mohammad Sayem; Mairpady, Anusha; Pervez, Hifsa; Kannuri, Uma Maheshwara

2017-01-20

In recent years, the development and use of polymeric nanocomposites in creating advanced materials has expanded exponentially. A substantial amount of research has been done in order to design polymeric nanocomposites in a safe and efficient manner. In the present study, the impact of processing parameters, such as, barrel temperature, and residence time on the mechanical and thermal properties of high density polyethylene (HDPE)-TiO₂ nanocomposites were investigated. Additionally, scanning electron microscopy and X-ray diffraction spectroscopy were used to analyze the dispersion, location, and phase morphology of TiO₂ on the HDPE matrix. Mechanical tests revealed that tensile strength of the fabricated HDPE-TiO₂ nanocomposites ranged between 22.53 and 26.30 MPa, while the Young's modulus showed a consistent increase as the barrel temperature increased from 150 °C to 300 °C. Moreover, the thermal stability decreased as the barrel temperature increased.

Co3O4/reduced graphene oxide nanocomposite for removal of organic pollutants from aqueous medium

Science.gov (United States)

Mishra, Amodini; Kuanr, B. K.; Mohanty, T.

2017-05-01

The magnetic nanocomposite (MNC) of cobalt oxide/graphene oxide (Co3O4/rGO) has been synthesized by hydrothermal method to demonstrate its use as organic pollutants remover. The phase formation of the cobalt oxide magnetic nanoparticles (MNPs) has been confirmed by X-ray diffraction (XRD) analysis. The nanocomposite has been characterized by Raman spectroscopic technique and two Raman peaks associated with graphene oxide are observed. The morphological study of the nanocomposite has been done using scanning electron microscope (SEM). The nanocomposite has been used for removal of organic pollutants from aqueous medium by using ultra-violet spectroscopy.

High pressure synthesis of zeolite/polymer nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Haines, Julien; Thibaud, Jean-Marc; Rouquette, Jerome; Cambon, Olivier; Di Renzo, Francesco, E-mail: julien.haines@univ-montp2.fr [Institut Charles Gerhardt Montpellier (France); Lee, Arie van der [Institut Europeen des Membranes, Montpellier (France); Scelta, Demetrio; Ceppatelli, Matteo; Dziubek, Kamil; Gorelli, Federico; Bini, Roberto; Santoro, Mario [European Laboratory for Non Linear Spectroscopy, Firenze (Italy)

2016-07-01

Full text: Polymerization of simple organic molecules under high pressure in the subnanometric pores of pure SiO{sub 2} zeolites can be used to produce novel nanocomposite materials, which can be recovered at ambient P and have remarkable mechanical, electrical or optical properties. Polymerization of ethylene in silicalite was studied in situ at high pressure by IR and results in a nanocomposite with isolated chains of non-conducting polyethylene strongly confined in the pores based on single crystal x-ray diffraction data. The nanocomposite is much less compressible than silicalite and has a positive rather than a negative thermal expansion coefficient. In order to target novel electrical and optical properties, isolated chains of conducting polymers can also be prepared in the pores of zeolite hosts at high pressure, such as polyacetylene, which was polymerized under pressure in the pores of the 1-D zeolite TON. The structure of this nanocomposite was determined by synchrotron x-ray powder diffraction data with complete pore filling corresponding to one planar polymer chain confined in each pore with a zig-zag configuration in the yz plane. This very strong confinement can be expected to strongly modify the electrical properties of polyacetylene. In this nanocomposite, our theoretical calculations indicate that the electronic density of states of polyacetylene exhibit van Hove singularities related to quantum 1D confinement, which could lead to future technological applications. This new material is susceptible to have applications in nanoelectronics, nanophotonics and energy and light harvesting. Completely novel nanocomposites were prepared by the polymerization of carbon monoxide CO in silicalite and TON. In these materials, isolated, ideal polycarbonyl chains are obtained in contrast to the non-stoichiometric, branched bulk polymers obtained by high pressure polymerization of this simple system. These poly CO/zeolite composites could be interesting energetic

ANALYTICAL REVIEW OF ELECTRONIC RESOURCES FOR THE STUDY OF LATIN

Directory of Open Access Journals (Sweden)

Olena Yu. Balalaieva

2014-04-01

Full Text Available The article investigates the current state of development of e-learning content in the Latin language. It is noted that the introduction of ICT in the educational space has expanded the possibility of studying Latin, opened access to digital libraries resources, made it possible to use scientific and educational potential and teaching Latin best practices of world's leading universities. A review of foreign and Ukrainian information resources and electronic editions for the study of Latin is given. Much attention was paid to the didactic potential of local and online multimedia courses of Latin, electronic textbooks, workbooks of interactive tests and exercises, various dictionaries and software translators, databases and digital libraries. Based on analysis of the world market of educational services and products the main trends in the development of information resources and electronic books are examined. It was found that multimedia courses with interactive exercises or workbooks with interactive tests, online dictionaries and translators are the most widely represented and demanded. The noticeable lagging of Ukrainian education and computer linguistics in quantitative and qualitative measures in this industry is established. The obvious drawback of existing Ukrainian resources and electronic editions for the study of Latin is their noninteractive nature. The prospects of e-learning content in Latin in Ukraine are outlined.

Nanocomposites prepared from acrylonitrile butadiene rubber and organically modified montmorillonite with vinyl groups

Science.gov (United States)

Han, Mijeong; Kim, Hoonjung; Kim, Eunkyoung

2006-01-01

Nanocomposites were prepared from acrylonitrile-butadiene rubber (NBR), vinyl groups containing organically modified montmorillonite and additives, such as zinc oxide, stearic acid, and sulfur. The organically modified montmorillonites used in these nanocomposites were prepared by ion exchange reactions of N,N'-dimethylalkyl-(p-vinylbenzyl)-ammonium chlorides (DAVBAs, alkyl = octyl, dodecyl, and octadecyl) with sodium montmorillonite (Na+-MMT). NBR nanocomposites were obtained by controlling both the mixing and vulcanization conditions, by using a Brabender mixer and hot-press process. X-ray diffraction (XRD) analysis shows that, depending on the amount of montmorillonite that is added, both exfoliated and intercalated nanocomposite structures are formed. The NBR/DAVBA-MMT nanocomposites exhibit much higher mechanical properties (e.g., tensile strength, Young's modulus, 300% modulus, and hardness) as well as gas barrier properties as compared to NBR Na+-MMT or NBR composites generated from modified montmorillonites without vinyl groups. Consistent with the results of XRD, transmission electron microscopy (TEM) reveals that the intercalation and exfoliation structures of the nanocomposites coexist and that the DAVBA-MMT layers are well dispersed in NBR.

The enhanced coercivity for the magnetite/silica nanocomposite at room temperature

International Nuclear Information System (INIS)

Wu Mingzai; Xiong Ying; Peng Zhenmeng; Jiang Nan; Qi Haiping; Chen Qianwang

2004-01-01

Magnetite/silica nanocomposite was synthesized by a facile solvothermal processing at 150 deg. C for about 10 h. X-ray diffraction (XRD) analysis revealed the effect of annealing on the crystallinity of silica. Transmission electron microscopy (TEM) images showed the good dispersion of magnetite in the silica matrix. Magnetic properties of the nanocomposite were characterized by vibration sample magnetometer (VSM), and the enhanced coercivity was explained by the intrinsic anisotropy of the particles enhanced by the interparticle dipolar fields

Elektronik Bilgi Kaynaklarının Seçimi / Selection of Electronic Information Resources

Directory of Open Access Journals (Sweden)

Pınar Al

2003-04-01

Full Text Available For many years, library users have used only from the printed media in order to get the information that they have needed. Today with the widespread use of the Web and the addition of electronic information resources to library collections, the use of information in the electronic environment as well as in printed media is started to be used. In time, such types of information resources as, electronic journals, electronic books, electronic encyclopedias, electronic dictionaries and electronic theses have been added to library collections. In this study, selection criteria that can be used for electronic information resources are discussed and suggestions are provided for libraries that try to select electronic information resources for their collections.

Synthesis and characterization of poly(methyl methacrylate)/OMMT nanocomposites by γ-ray irradiation polymerization

International Nuclear Information System (INIS)

Zhang Weian; Shen Xiaofeng; Li Yu; Fang Yuee

2003-01-01

Organophilic montmorillonite (OMMT) was synthesized by cationic exchange between Na-MMT and cetyltrimethylammonium bromide in an aqueous solution. Poly(methyl methacrylate)(PMMA)/(OMMT) nanocomposites was prepared by γ-ray irradiation polymerization. The dispersion degree and the intercalation spacing of these nanocomposites were investigated with the X-ray diffraction and high-resolution transmission electron microscopy, respectively. The thermal stabilities of the samples were studied by the thermal gravimetric analysis. The nanocomposites had higher storage modulus and higher glass transition temperature (T g ) than the pure PMMA, which were measured by dynamic mechanical analysis

A novel thermal decomposition approach to synthesize hydroxyapatite-silver nanocomposites and their antibacterial action against GFP-expressing antibiotic resistant E. coli.

Science.gov (United States)

Sahni, Geetika; Gopinath, P; Jeevanandam, P

2013-03-01

A novel thermal decomposition approach to synthesize hydroxyapatite-silver (Hap-Ag) nanocomposites has been reported. The nanocomposites were characterized by X-ray diffraction, field emission scanning electron microscopy coupled with energy dispersive X-ray analysis, transmission electron microscopy and diffuse reflectance spectroscopy techniques. Antibacterial activity studies for the nanocomposites were explored using a new rapid access method employing recombinant green fluorescent protein (GFP) expressing antibiotic resistant Escherichia coli (E. coli). The antibacterial activity was studied by visual turbidity analysis, optical density analysis, fluorescence spectroscopy and microscopy. The mechanism of bactericidal action of the nanocomposites on E. coli was investigated using atomic force microscopy, and TEM analysis. Excellent bactericidal activity at low concentration of the nanocomposites was observed which may allow their use in the production of microbial contamination free prosthetics. Copyright © 2012 Elsevier B.V. All rights reserved.

Access to electronic resources by visually impaired people

Directory of Open Access Journals (Sweden)

Jenny Craven

2003-01-01

Full Text Available Research into access to electronic resources by visually impaired people undertaken by the Centre for Research in Library and Information Management has not only explored the accessibility of websites and levels of awareness in providing websites that adhere to design for all principles, but has sought to enhance understanding of information seeking behaviour of blind and visually impaired people when using digital resources.

Novel amperometric glucose biosensor based on MXene nanocomposite

KAUST Repository

Rakhi, R. B.

2016-11-10

A biosensor platform based on Au/MXene nanocomposite for sensitive enzymatic glucose detection is reported. The biosensor leverages the unique electrocatalytic properties and synergistic effects between Au nanoparticles and MXene sheets. An amperometric glucose biosensor is fabricated by the immobilization of glucose oxidase (GOx) enzyme on Nafion solubilized Au/ MXene nanocomposite over glassy carbon electrode (GCE). The biomediated Au nanoparticles play a significant role in facilitating the electron exchange between the electroactive center of GOx and the electrode. The GOx/Au/MXene/Nafion/GCE biosensor electrode displayed a linear amperometric response in the glucose concentration range from 0.1 to 18 mM with a relatively high sensitivity of 4.2 μAmM−1 cm−2 and a detection limit of 5.9 μM (S/N = 3). Furthermore, the biosensor exhibited excellent stability, reproducibility and repeatability. Therefore, the Au/MXene nanocomposite reported in this work is a potential candidate as an electrochemical transducer in electrochemical biosensors.

Novel amperometric glucose biosensor based on MXene nanocomposite

KAUST Repository

Baby, Rakhi Raghavan; Nayuk, Pranati; Xia, Chuan; Alshareef, Husam N.

2016-01-01

A biosensor platform based on Au/MXene nanocomposite for sensitive enzymatic glucose detection is reported. The biosensor leverages the unique electrocatalytic properties and synergistic effects between Au nanoparticles and MXene sheets. An amperometric glucose biosensor is fabricated by the immobilization of glucose oxidase (GOx) enzyme on Nafion solubilized Au/ MXene nanocomposite over glassy carbon electrode (GCE). The biomediated Au nanoparticles play a significant role in facilitating the electron exchange between the electroactive center of GOx and the electrode. The GOx/Au/MXene/Nafion/GCE biosensor electrode displayed a linear amperometric response in the glucose concentration range from 0.1 to 18 mM with a relatively high sensitivity of 4.2 μAmM−1 cm−2 and a detection limit of 5.9 μM (S/N = 3). Furthermore, the biosensor exhibited excellent stability, reproducibility and repeatability. Therefore, the Au/MXene nanocomposite reported in this work is a potential candidate as an electrochemical transducer in electrochemical biosensors.

Graphene oxide--MnO2 nanocomposites for supercapacitors.

Science.gov (United States)

Chen, Sheng; Zhu, Junwu; Wu, Xiaodong; Han, Qiaofeng; Wang, Xin

2010-05-25

A composite of graphene oxide supported by needle-like MnO(2) nanocrystals (GO-MnO(2) nanocomposites) has been fabricated through a simple soft chemical route in a water-isopropyl alcohol system. The formation mechanism of these intriguing nanocomposites investigated by transmission electron microscopy and Raman and ultraviolet-visible absorption spectroscopy is proposed as intercalation and adsorption of manganese ions onto the GO sheets, followed by the nucleation and growth of the crystal species in a double solvent system via dissolution-crystallization and oriented attachment mechanisms, which in turn results in the exfoliation of GO sheets. Interestingly, it was found that the electrochemical performance of as-prepared nanocomposites could be enhanced by the chemical interaction between GO and MnO(2). This method provides a facile and straightforward approach to deposit MnO(2) nanoparticles onto the graphene oxide sheets (single layer of graphite oxide) and may be readily extended to the preparation of other classes of hybrids based on GO sheets for technological applications.

Fabrication of Mesoporous Silica/Alumina Hybrid Membrane Film Nanocomposites using Template Sol-Gel Synthesis of Amphiphilic Triphenylene

Science.gov (United States)

Lintang, H. O.; Jalani, M. A.; Yuliati, L.; Salleh, M. M.

2017-05-01

Herein we reported that by introducing a one-dimensional (1D) substrate with a porous structure such as anodic aluminum oxide (AAO) membrane, mesoporous silica/alumina hybrid nanocomposites were successfully fabricated by using amphiphilic triphenylene (TPC10TEG) as a template in sol-gel synthesis (TPC10TEG/silicahex). For the optical study of the nanocomposites, TPC10TEG/silicahex showed absorption peak at 264 nm due to the ordered and long-range π-π stacking of the disc-like aromatic triphenylene core. Moreover, the hexagonal arrangement of TPC10TEG/silicahex was proven based on their diffraction peaks of d 100 and d 200 at 2θ = 2.52° and 5.04° and images of transmission electron microscopy (TEM), respectively. For fabrication of mesoporous silica/alumina hybrid membrane, TPC10TEG/silicahex was drop-casted onto AAO membrane for penetration into the porous structure via gravity. X-ray diffraction (XRD) analysis on the resulted hybrid nanocomposites showed that the diffraction peaks of d 100 and d 200 of TPC10TEG/silicahex were still preserved, indicating that the hexagonal arrangements of mesoporous silica were maintained even on AAO substrate. The morphology study on the hybrid nanocomposites using TEM, scanning electron microscope (SEM) and field emission scanning electron microscope (FE-SEM) showed the successful filling of most AAO channels with the TPC10TEG/silicahex nanocomposites.

Influence of carbon nano tubes on mechanical, metallurgical and tribological behavior of magnesium nanocomposites

Directory of Open Access Journals (Sweden)

S.T. Selvamani

2017-09-01

Full Text Available In this research work, three different reinforcements of Carbon Nano Tubes (in weight % such as 2%, 3% and 4% were added to the magnesium AZ91D grade magnesium alloy to fabricate the Nanocomposites through stir casting method. The effects of volume percentage on the mechanical, metallurgical and wear behavior were analyzed. The composites with 4% reinforcement show high hardness while the composites with 3% reinforcement show better tensile and yield strength and also an improved wear resistance compared to other. Also, the characterization of the Nanocomposites were made using Optical Microscopy, Scanning Electron Microscopy, Finite Element – Scanning Electron Microscopy and Transmission Electron Microscopy to understand its nature.

A Study of Clay-Epoxy Nanocomposites Consisting of Unmodified Clay and Organo Clay

Directory of Open Access Journals (Sweden)

Graham Edward

2006-04-01

Full Text Available Clay-epoxy nanocomposites were synthesized from DGEBA resin and montmorillonite clay with an in-situ polymerization. One type of untreated clay and two types of organo clay were used to produce the nanocompsoites. The aims of this study were to examine the nanocomposite structure using different tools and to compare the results between the unmodified clay and modified clays as nanofillers. Although diffractogram in reflection mode did not show any apparent peak of both types of materials, the transmitted XRD (X-Ray Difraction graphs, DSC (Differential Scanning Calorimeter analysis and TEM (Transmission Electron Microscope images revealed that the modified clay-epoxy and unmodified clay-epoxy provides different results. Interestingly, the micrographs showed that some of the modified clay layers possessed non-exfoliated layers in the modified clay-epoxy nanocomposites. Clay aggregates and a hackle pattern were found from E-SEM images for both types of nanocomposite materials. It is shown that different tools should be used to determine the nanocomposite structure.

Green Synthesis, Characterization, and Antibacterial Activity of Silver/Polystyrene Nanocomposite

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Manal A. Awad

2015-01-01

Full Text Available A novel, nontoxic, simple, cost-effective and ecofriendly technique was used to synthesize green silver nanoparticles (AgNPs. The AgNPs were synthesized using orange peel extract as a reducing agent for silver nitrate salt (AgNO3. The particle size distribution of AgNPs was determined by Dynamic Light Scattering (DLS. The average size of silver nanoparticles was 98.43 nm. The stable dispersion of silver nanoparticles was added slowly to polystyrene solution in toluene maintaining the temperature at 70°C. The AgNPs/polystyrene (PS nanocomposite solution was cast in a petri dish. The silver nanoparticles encapsulated within polymer chains were characterized by X-ray diffraction (XRD and Scanning Electron Microscopy (SEM equipped with Energy Dispersive Spectroscopy (EDS in addition to Transmission Electron Microscopy (TEM. The green AgNPs/PS nanocomposite film exhibited antimicrobial activity against Gram-negative bacteria Escherichia coli, Klebsiella pneumoniae and Salmonella, and Gram-positive bacteria Staphylococcus aureus. Thus, the key findings of the work include the use of a safe and simple AgNPs/PS nanocomposite which had a marked antibacterial activity which has a potential application in food packaging.

Drug-Carrying Magnetic Nanocomposite Particles for Potential Drug Delivery Systems

Directory of Open Access Journals (Sweden)

R. Asmatulu

2009-01-01

nanoparticles and poly (D,L-lactide-co-glycolide (PLGA for the purpose of magnetic targeted drug delivery. Magnetic nanoparticles (∼13 nm on average of magnetite were prepared by a chemical coprecipitation of ferric and ferrous chloride salts in the presence of a strong basic solution (ammonium hydroxide. An oil-in-oil emulsion/solvent evaporation technique was conducted at 7000 rpm and 1.5–2 hours agitation for the synthesis of nanocomposite spheres. Specifically, PLGA and drug were first dissolved in acetonitrile (oily phase I and combined with magnetic nanoparticles, then added dropwise into viscous paraffin oil combined with Span 80 (oily phase II. With different contents (0%, 10%, 20%, and 25% of magnetite, the nanocomposite spheres were evaluated in terms of particle size, morphology, and magnetic properties by using dynamic laser light scattering (DLLS, scanning electron microscopy (SEM, transmission electron microscopy (TEM, and a superconducting quantum interference device (SQUID. The results indicate that nanocomposite spheres (200 nm to 1.1 μm in diameter are superparamagnetic above the blocking temperature near 40 K and their magnetization saturates above 5 000 Oe at room temperature.

Exfoliated graphite/titanium dioxide nanocomposites for photodegradation of eosin yellow

International Nuclear Information System (INIS)

Ndlovu, Thabile; Kuvarega, Alex T.; Arotiba, Omotayo A.; Sampath, Srinivasan; Krause, Rui W.; Mamba, Bhekie B.

2014-01-01

Graphical abstract: - Highlights: • Preparation of exfoliated graphite (EG) from natural graphite. • Sol–gel anchoring of TiO 2 on exfoliated graphite. • High adsorption and photoactivity was observed for the EG-TiO 2 nanocomposite. • Mechanism of enhancement was proposed. - Abstract: An improved photocatalyst consisting of a nanocomposite of exfoliated graphite and titanium dioxide (EG-TiO 2 ) was prepared. SEM and TEM micrographs showed that the spherical TiO 2 nanoparticles were evenly distributed on the surface of the EG sheets. A four times photocatalytic enhancement was observed for this floating nanocomposite compared to TiO 2 and EG alone for the degradation of eosin yellow. For all the materials, the reactions followed first order kinetics where for EG-TiO 2 , the rate constant was much higher than for EG and TiO 2 under visible light irradiation. The enhanced photocatalytic activity of EG-TiO 2 was ascribed to the capability of graphitic layers to accept and transport electrons from the excited TiO 2 , promoting charge separation. This indicates that carbon, a cheap and abundant material, can be a good candidate as an electron attracting reservoir for photocatalytic organic pollutant degradation

Green synthesis, characterization, and anticancer activity of hyaluronan/zinc oxide nanocomposites

Directory of Open Access Journals (Sweden)

Namvar F

2016-07-01

Full Text Available Farideh Namvar,1,2 Susan Azizi,3 Heshu Sulaiman Rahman,4–6 Rosfarizan Mohamad,1,3 Abdullah Rasedee,4 Mozhgan Soltani,2 Raha Abdul Rahim71Institute of Tropical Forestry and Forest Products (INTROP, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia; 2Research Center for Animal Development Applied Biology, Mashhad Branch, Islamic Azad University, Mashhad, Iran; 3Department of Bioprocess Technology, Faculty of Biotechnology and Biomolecular Sciences, 4Department of Veterinary Laboratory Diagnosis, Faculty of Veterinary Medicine, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia; 5Department of Clinic and Internal Medicine, College of Veterinary Medicine, University of Sulaimani, 6Department of Laboratory Medical Sciences, Komar University of Science and Technology, Sulaimani City, Kurdistan Region, Northern Iraq; 7Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, UPM Serdang, Selangor, Malaysia Abstract: The study describes an in situ green biosynthesis of zinc oxide nanocomposite using the seaweed Sargassum muticum water extract and hyaluronan biopolymer. The morphology and optical properties of the hyaluronan/zinc oxide (HA/ZnO nanocomposite were determined by Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and ultraviolet–vis analysis. Electron microscopy and X-ray diffraction analysis showed that the zinc oxide nanoparticles were polydispersed with a mean size of 10.2±1.5 nm. The nanoparticles were mostly hexagonal in crystalline form. The HA/ZnO nanocomposite showed the absorption properties in the ultraviolet zone that is ascribed to the band gap of zinc oxide nanocomposite. In the cytotoxicity study, cancer cells, pancreatic adenocarcinoma (PANC-1, ovarian adenocarcinoma (CaOV-3, colonic adenocarcinoma (COLO205, and acute promyelocytic leukemia (HL-60 cells

Library training to promote electronic resource usage

DEFF Research Database (Denmark)

Frandsen, Tove Faber; Tibyampansha, Dativa; Ibrahim, Glory

2017-01-01

Purpose: Increasing the usage of electronic resources is an issue of concern for many libraries all over the world. Several studies stress the importance of information literacy and instruction in order to increase the usage. Design/methodology/approach: The present article presents the results...

Why and How to Measure the Use of Electronic Resources

Directory of Open Access Journals (Sweden)

Jean Bernon

2008-11-01

Full Text Available A complete overview of library activity implies a complete and reliable measurement of the use of both electronic resources and printed materials. This measurement is based on three sets of definitions: document types, use types and user types. There is a common model of definitions for printed materials, but a lot of questions and technical issues remain for electronic resources. In 2006 a French national working group studied these questions. It relied on the COUNTER standard, but found it insufficient and pointed out the need for local tools such as web markers and deep analysis of proxy logs. Within the French national consortium COUPERIN, a new working group is testing ERMS, SUSHI standards, Shibboleth authentication, along with COUNTER standards, to improve the counting of the electronic resources use. At this stage this counting is insufficient and its improvement will be a European challenge for the future.

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.

Irradiation induced crossover from 1D to 3D transport behaviors of PEDOT-titanium dioxide hybrid nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Sarmah, Smritimala [Department of Physics, Girijananda Chowdhury Institute of Management and Technology, Guwahati 781017, Assam (India); Kumar, A. [Materials Research Laboratory, Department of Physics, Tezpur University, Tezpur 784028, Assam (India)

2012-12-15

Conductive poly(3,4-ethylenedioxythiophene)/TiO{sub 2} nanocomposites were synthesized via a facile oxidative polymerization approach using dodecylbenzene sulfonic acid as a dopant and ammonium peroxydisulfate as an oxidant and irradiated with 90 MeV O{sup 7+} ions at the fluences of 5 x 10{sup 10}, 1 x 10{sup 11}, 5 x 10{sup 11}, and 1 x 10{sup 12} ions cm{sup -2} using 15UD Pelletron accelerator under high vacuum. X-ray diffraction studies show that microstrain and domain crystallite size of the nanocomposites increases with the increase of ion fluence resulting in highly ordered PEDOT-TiO{sub 2} nanocomposites. Thermogravimmetric analysis shows that the thermal stability of the nanocomposites increases with the increase of irradiation fluences which can be attributed to the crosslinking of polymer chains due to high electronic energy deposition. Scanning electron micrographs show that there is grain growth after swift heavy ion (SHI) irradiation resulting highly dense and less porous microstructure of nanocomposite films. DC conductivity of unirradiated nanocomposites exhibits Mott's 1D variable range hopping (VRH) mechanism. However, there is cross over to 3D VRH mechanism at higher irradiation fluence of 5 x 10{sup 11} and 1 x 10{sup 12} ions cm{sup -2}. There is an enhancement in the electrical conductivity of the nanocomposites upon SHI irradiation correlating crosslinking with DC conductivity of the nanocomposites. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Preparation and thermomechanical properties of Ag-PVA nanocomposite films

International Nuclear Information System (INIS)

Gautam, Anurag; Ram, S.

2010-01-01

Metal-polymer hybrid nanocomposites have been prepared from an aqueous solution of polyvinyl alcohol (PVA) and silver nitrate (AgNO 3 ). The silver nanoparticles were generated in PVA matrix by the reduction of silver ions with PVA molecule at 60-70 deg. C over magnetic stirrer. UV-vis analysis, X-ray diffraction studies, transmission electron microscopy, scanning electron microscopy and current-voltage analysis were used to characterize the nanocomposite films prepared. The X-ray diffraction analysis reveals that silver metal is present in face centered cubic (fcc) crystal structure. Average crystallite size of silver nanocrystal is 19 nm, which increases to 22 nm on annealing the film at 150 deg. C in air. This result is in good agreement with the result obtained from TEM. The UV-vis spectrum shows a single peak at 433 nm, arising from the surface plasmon absorption of silver nanocolloids. This result clearly indicates that silver nanoparticles are embedded in PVA. An improvement of mechanical properties (storage modulus) was also noticed due to a modification of PVA up to 0.5 wt% of silver content. The current-voltage (I-V) characteristic of nanocomposite films shows increase in current drawn with increasing Ag-content in the films.

Morphological, rheological and mechanical characterization of polypropylene nanocomposite blends.

Science.gov (United States)

Rosales, C; Contreras, V; Matos, M; Perera, R; Villarreal, N; García-López, D; Pastor, J M

2008-04-01

In the present work, the effectiveness of styrene/ethylene-butylene/styrene rubbers grafted with maleic anhydride (MA) and a metallocene polyethylene (mPE) as toughening materials in binary and ternary blends with polypropylene and its nanocomposite as continuous phases was evaluated in terms of transmission electron microscopy (TEM), scanning electron microscopy (SEM), oscillatory shear flow and dynamic mechanical thermal analysis (DMA). The flexural modulus and heat distortion temperature values were determined as well. A metallocene polyethylene and a polyamide-6 were used as dispersed phases in these binary and ternary blends produced via melt blending in a corotating twin-screw extruder. Results showed that the compatibilized blends prepared without clay are tougher than those prepared with the nanocomposite of PP as the matrix phase and no significant changes in shear viscosity, melt elasticity, flexural or storage moduli and heat distortion temperature values were observed between them. However, the binary blend with a nanocomposite of PP as matrix and metallocene polyethylene phase exhibited better toughness, lower shear viscosity, flexural modulus, and heat distortion temperature values than that prepared with polyamide-6 as dispersed phase. These results are related to the degree of clay dispersion in the PP and to the type of morphology developed in the different blends.

Poly(o-phenylenediamine)/NiCoFe2O4 nanocomposites: Synthesis, characterization, magnetic and dielectric properties

Science.gov (United States)

Kannapiran, Nagarajan; Muthusamy, Athianna; Chitra, Palanisamy; Anand, Siddeswaran; Jayaprakash, Rajan

2017-02-01

In this study, poly(o-phenylenediamine) (PoPD)/NiCoFe2O4 nanocomposites were synthesized by in-situ oxidative chemical polymerization method with different amount of NiCoFe2O4 nanoparticles. The NiCoFe2O4 nanoparticles were prepared by auto-combustion method. The structural, morphological, thermal properties of the synthesized PoPD/NiCoFe2O4 nanocomposites were characterized by fourier transform infrared spectrum (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). Magnetic properties of NiCoFe2O4 nanoparticles and PoPD/NiCoFe2O4 nanocomposites were studied by vibrating sample magnetometer (VSM). The FTIR and XRD techniques were used to confirm the formation of PoPD/NiCoFe2O4 nanocomposites. The average crystalline size of NiCoFe2O4 nanoparticles and PoPD/NiCoFe2O4 nanocomposites were calculated from XRD. From the SEM analysis, spherical morphology of the PoPD was confirmed. The TGA results showed that the NiCoFe2O4 nanoparticles have improved the thermal stability of PoPD. Dielectric properties of PoPD/NiCoFe2O4 nanocomposites at different temperatures have been carried in the frequency range 50 Hz to 5 MHz.

Preparation and Characterization of WS2@SiO2 and WS2@PANI Core-Shell Nanocomposites

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Hagit Sade

2018-03-01

Full Text Available Two tungsten disulfide (WS2-based core-shell nanocomposites were fabricated using readily available reagents and simple procedures. The surface was pre-treated with a surfactant couple in a layer-by-layer approach, enabling good dispersion of the WS2 nanostructures in aqueous media and providing a template for the polymerization of a silica (SiO2 shell. After a Stöber-like reaction, a conformal silica coating was achieved. Inspired by the resulting nanocomposite, a second one was prepared by reacting the surfactant-modified WS2 nanostructures with aniline and an oxidizing agent in an aqueous medium. Here too, a conformal coating of polyaniline (PANI was obtained, giving a WS2@PANI nanocomposite. Both nanocomposites were analyzed by electron microscopy, energy dispersive X-ray spectroscopy (EDS and FTIR, verifying the core-shell structure and the character of shells. The silica shell was amorphous and mesoporous and the surface area of the composite increases with shell thickness. Polyaniline shells slightly differ in their morphologies dependent on the acid used in the polymerization process and are amorphous like the silica shell. Electron paramagnetic resonance (EPR spectroscopy of the WS2@PANI nanocomposite showed variation between bulk PANI and the PANI shell. These two nanocomposites have great potential to expand the use of transition metals dichalcogenides (TMDCs for new applications in different fields.

Scanning transmission electron microscopy analysis of Ge(O)/(graphitic carbon nitride) nanocomposite powder

Energy Technology Data Exchange (ETDEWEB)

Kawasaki, Masahiro [JEOL USA Inc., 11 Dearborn Road, Peabody, MA 01960 (United States); Sompetch, Kanganit [Department of Chemistry and Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Sarakonsri, Thapanee, E-mail: tsarakonsri@gmail.com [Department of Chemistry and Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Shiojiri, Makoto [Kyoto Institute of Technology, Kyoto 606-8585 (Japan); School of Science and Engineering, University of Toyama, Toyama 930-8555 (Japan)

2015-12-15

Analytical electron microscopy has revealed the structure of particles that were synthesized by chemical reaction of GeO{sub 2} with NaBH{sub 4} in the basic solution including graphitic carbon nitride (g-C{sub 3}N{sub 4}) powders. The g-C{sub 3}N{sub 4} was arranged by recrystallization of melamine at 600 °C under N{sub 2} gas atmosphere. The samples were dried at 60 °C or 180 °C for 4 h. The g-C{sub 3}N{sub 4} was observed as lamellae of several ten nm or less in size and had an amorphous-like structure with a distorted lattice in an area as small as a few hundred pm in size. The reaction product was Ge(O) particles as fine as several nm in size and composed of Ge and O atoms. Most of the particles must be of GeO{sub 2−x} with the amorphous-like structure that has also a distorted lattice in an area of a few hundred pm in size. In the sample dried at 60 °C, the particles were found to be dispersed in a wide area on the g-C{sub 3}N{sub 4} lamella. It is hard to recognize those particles in TEM images. The particles in the sample dried at 180 °C became larger and were easily observed as isolated lumps. Hence, these powders can be regarded as GeO{sub 2}/g-C{sub 3}N{sub 4} or Ge/GeO{sub 2}/g-C{sub 3}N{sub 4} nanocomposites, and expected to be applicable to anode materials for high energy Li-ion batteries due to Ge catalysis effect, accordingly. - Graphical abstract: STEM analysis of Ge(O)/(graphitic carbon nitride) nanocomposite powder. - Highlights: • Graphitic (g)-C{sub 3}N{sub 4} powder was prepared at 600 °C by recrystallization of melamine. • Ge(O) was prepared by chemical reaction in a solution including the g-C{sub 3}N{sub 4} powders. • The products can be regarded as GeO{sub 2}/g-C{sub 3}N{sub 4} or Ge/GeO{sub 2}/g-C{sub 3}N{sub 4} nanocomposites. • GeO{sub 2} was amorphous several-nm particles and g-C{sub 3}N{sub 4} was amorphous lamella of several 10 nm in size. • We expect them to be applicable for high energy Li-ion battery anode

Nonlinear optical properties of ZnO/poly (vinyl alcohol) nanocomposite films

International Nuclear Information System (INIS)

Jeeju, P. P.; Jayalekshmi, S.; Chandrasekharan, K.

2014-01-01

Extensive studies have already been reported on the optical characteristics of ZnO/polymer nanocomposite films, using a variety of polymers including transparent polymers such as polystyrene, polymethyl methacrylate etc and many interesting results have been established regarding the non linear optical characteristics of these systems. Poly (vinyl alcohol)(PVA) is a water soluble polymer. Though the structural and optical studies of ZnO/PVA nanocomposite films have already been investigated, there are no detailed reports on the nonlinear optical characteristics of ZnO/PVA nanocomposite films, irrespective of the fact that these nanocomposite films can be synthesized using quite easy and cost effective methods. The present work is an attempt to study in detail the nonlinear optical behaviour of ZnO/PVA nanocomposite films using Z-scan technique. Highly transparent ZnO/PVA nanocomposite films were prepared from the ZnO incorporated PVA solution in water using spin coating technique. The ZnO nanoparticles were synthesized by the simple chemical route at room temperature. High-resolution transmission electron microscopy studies show that the ZnO nanoparticles are of size around 10 nm. The ZnO/PVA nanocomposite films were structurally characterized by X-ray diffraction technique, from which the presence of both PVA and ZnO in the nanocomposite was established. The optical absorptive nonlinearity in the nanocomposite films was investigated using open aperture Z-scan technique. The results indicate optical limiting type nonlinearity in the films due to two photon absorption in ZnO with efficiency more than 50%. These films also show a self defocusing type negative nonlinear refraction in closed aperture Z-scan experiment. The present studies indicate that, highly transparent and homogeneous films of ZnO/PVA nanocomposite can be obtained on glass substrates using simple methods, in a highly cost effective way, since PVA is water soluble. These nanocomposite films offer

Effect of Nanosilica Type on Properties of Polyethylene Terephthalane/Silica Nanocomposite

Directory of Open Access Journals (Sweden)

Mazeyar Parvinzadeh Gashti

2012-12-01

Full Text Available This research is carried out to study some properties of polyethylene terephthalaten (PET as one of the most important synthetic polymers used in textile industry. PET based nanocomposites containing three differently modified silica particles were prepared by melt compounding. The influence of type and amount of nanosilica on various properties of nanocomposite was studied by Fourier transform infrared spectroscopy, scanning electron microscopy, contact angle determination, optical microscopy, differential scanning calorimetry, thermal gravimetry analyzer and dynamic mechanical thermal analyzer. ATR results indicated that the interactions ofhydrophilic nanosilica mainly occur at the surface of nanocomposites. SEM was used to confirm the presence of silica on the surface of nanocomposites and it showed that surface properties depend on hydrophilicity of nanosilica. Studies on surface tension of nanocomposites showed that modified nanosilica particles have higher tendency to remain in bulk polymer as compared with unmodified one. Optical microscopy images from nanocomposites-containing silica illustrated the increment of thenumber of spherulites in the PET matrix with increases in silica percentage which were dependent on nano-silica type and content. Differential scanning calorimetry results of the nanocomposites showed a slight drop in the melting temperature compared to pure PET. The results obtained from thermal stability test showed that any improvement in thermal stability depends on the type of silica and dispersion of particles in polyethylene terephthalate. Moreover, the extent of interactions between nanosilica particles and polyethylene terephthatale chains affects on thermal stability of the composite.of the composite.

Fabrication and magnetic properties of granular Co/porous InP nanocomposite materials

Directory of Open Access Journals (Sweden)

Ma Li

2011-01-01

Full Text Available Abstract A novel Co/InP magnetic semiconductor nanocomposite was fabricated by electrodeposition magnetic Co nanoparticles into n-type porous InP templates in ethanol solution of cobalt chloride. The content or particle size of Co particles embedded in porous InP increased with increasing deposition time. Co particles had uniform distribution over pore sidewall surface of InP template, which was different from that of ceramic template and may open up new branch of fabrication of nanocomposites. The magnetism of such Co/InP nanocomposites can be gradually tuned from diamagnetism to ferromagnetism by increasing the deposition time of Co. Magnetic anisotropy of this Co/InP nanocomposite with magnetization easy axis along the axis of InP square channel was well realized by the competition between shape anisotropy and magnetocrystalline anisotropy. Such Co/InP nanocomposites with adjustable magnetism may have potential applications in future in the field of spin electronics. PACS: 61.46. +w · 72.80.Tm · 81.05.Rm · 75.75. +a · 82.45.Aa

Fabrication and magnetic properties of granular Co/porous InP nanocomposite materials.

Science.gov (United States)

Zhou, Tao; Cheng, Dandan; Zheng, Maojun; Ma, Li; Shen, Wenzhong

2011-03-31

A novel Co/InP magnetic semiconductor nanocomposite was fabricated by electrodeposition magnetic Co nanoparticles into n-type porous InP templates in ethanol solution of cobalt chloride. The content or particle size of Co particles embedded in porous InP increased with increasing deposition time. Co particles had uniform distribution over pore sidewall surface of InP template, which was different from that of ceramic template and may open up new branch of fabrication of nanocomposites. The magnetism of such Co/InP nanocomposites can be gradually tuned from diamagnetism to ferromagnetism by increasing the deposition time of Co. Magnetic anisotropy of this Co/InP nanocomposite with magnetization easy axis along the axis of InP square channel was well realized by the competition between shape anisotropy and magnetocrystalline anisotropy. Such Co/InP nanocomposites with adjustable magnetism may have potential applications in future in the field of spin electronics.PACS: 61.46. +w · 72.80.Tm · 81.05.Rm · 75.75. +a · 82.45.Aa.

Dielectric properties of ligand-modified gold nanoparticle/SU-8 photopolymer based nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Toor, Anju, E-mail: atoor@berkeley.edu [Department of Mechanical Engineering, University of California, Berkeley, CA 94720 (United States); So, Hongyun, E-mail: hyso@berkeley.edu [Department of Mechanical Engineering, University of California, Berkeley, CA 94720 (United States); Pisano, Albert P. [Department of Mechanical Engineering, University of California, Berkeley, CA 94720 (United States); Department of Mechanical and Aerospace Engineering, University of California, San Diego, CA 92093 (United States)

2017-08-31

Highlights: • Ligand-modified gold NP/SU-8 nanocomposites were synthesized and demonstrated. • Particle agglomeration and dispersion were characterized with different NPs concentration. • Nanocomposites showed higher average dielectric permittivity compared to SU-8 only. • Relatively lower dielectric loss (average 0.09 at 1 kHz) was achieved with 10 % w/w NPs. - Abstract: This article reports the enhanced dielectric properties of a photodefinable polymer nanocomposite material containing sub–10 nm coated metal nanoparticles (NPs). The surface morphology of the synthesized dodecanethiol-functionalized gold NPs was characterized using the transmission electron microscopy (TEM). We investigated the particle agglomeration and dispersion during the various stages of the nanocomposite synthesis using TEM. Physical properties such as dielectric permittivity and dielectric loss were measured experimentally. The dependence of the dielectric permittivity and loss tangent on the particle concentration, and frequency was studied. Nanocomposite films showed an approximately three times enhancement in average dielectric constant over the polymer base value and an average dielectric loss of 0.09 at 1 kHz, at a filler loading of 10% w/w.

Characterization polyethylene terephthalate nanocomposites mixing with nano-silica and titanium oxide

Directory of Open Access Journals (Sweden)

Rusu Mircea A.

2017-01-01

Full Text Available Polyethylene terephthalate (PET based nanocomposites containing nano-silica (Aerosil (Degusa and titanium oxide (TiO2 (Merk were prepared by melt compounding. Influence of nano-silica and titanium oxide on properties of the resulting nanocomposites was investigated by scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR and atomic force microscopy (AFM. The possible interaction between nano-silica and titanium oxide particles with PET functional groups at bulk and surface was elucidated by transmission of FTIR-ATR spectroscopy. AFM studies of the resulting nanocomposites showed an increased surface roughness compared to pure PET. SEM images illustrated that nano-silica particles have tendency to migrate to the surface of the PET matrix much more than titanium oxide powder.

Chemically designed Pt/PPy nano-composite for effective LPG gas sensor.

Science.gov (United States)

Gaikwad, Namrata; Bhanoth, Sreenu; More, Priyesh V; Jain, G H; Khanna, P K

2014-03-07

Simultaneous in situ reduction of hexachloroplatinic acid by the amine group in the pyrrole monomer and oxidation of pyrrole to form polypyrrole (PPy) was examined. The reactions were performed at various temperatures to understand the degree of reduction of platinum precursor as well as doping of polypyrrole with Pt(II) chloro-complex. Spectroscopic images revealed different morphologies for the Pt/PPy nano-composite prepared at various temperatures. The as-prepared Pt/PPy nano-composite samples were tested for their ability to sense liquefied petroleum gas (LPG) which resulted in excellent sensing at relatively low temperature. The porous nature and ohmic contact between the PPy and platinum nanoparticles makes the as-prepared Pt/PPy nano-composite highly useful for sensors as well as electronic applications.

Power ultrasound effects for in situ compatibilization of polymer-clay nanocomposites

International Nuclear Information System (INIS)

Ryu, Joung Gul; Park, Sang Wan; Kim, Hyungsu; Lee, Jae Wook

2004-01-01

Polymer-clay nanocomposites of various concentrations were prepared by ultrasonically assisted polymerization and melt mixing processes. The sonication process using power ultrasonic wave was employed to enhance nano-scale dispersion during melt mixing of monomer, polymer and organically modified clay. According to the unique mode of power ultrasound wave, we expected enhanced breakup of layered silicate bundle and further reduction in the size of dispersed phase with better homogeneity compared to the in situ polymerization. The optimum conditions to perform stable exfoliated nanocomposites were studied by various compositions and conditions. Dispersion characteristics and morphology of the nanocomposites were verified by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Rheological behaviors were measured under dynamic frequency sweep mode using Rheometric science ARES

Thermoplastic polyurethane and multi-walled carbon nanotubes nanocomposites for electrostatic dissipation

International Nuclear Information System (INIS)

Lavall, Rodrigo L.; Sales, Juliana A. de; Borges, Raquel S.; Calado, Hallen D. R.; Machado, Jose C.; Windmoeller, Dario; Silva, Glaura G.; Lacerda, Rodrigo G.; Ladeira, Luiz O.

2010-01-01

Polyurethane/multi-walled carbon nanotube (MWCNT) nanocomposites have been prepared with nanotube concentrations between 0.01 wt% and 1 wt%. MWCNT as-synthesized samples with ∼74 nm diameter and ∼7 mm length were introduced by solution processing in the polyurethane matrix. Scanning electron microscopy (SEM) images demonstrated good dispersion and adhesion of the CNTs to the polymeric matrix. The C=O stretching band showed evidence of perturbation of the hydrogen interaction between urethanic moieties in the nanocomposites as compared to pure TPU. Differential scanning calorimetry and positron annihilation lifetime spectroscopy measurements allowed the detection of glass transition displacement with carbon nanotube addition. Furthermore, the electrical conductivity of the nanocomposites was significantly increased with the addition of CNT. (author)

Microwave absorbing property and complex permittivity and permeability of graphene–CdS nanocomposite

International Nuclear Information System (INIS)

Zhang, Dong-Dong; Zhao, Dong-Lin; Zhang, Ji-Ming; Bai, Li-Zhong

2014-01-01

Graphical abstract: Graphene–CdS (G–CdS) nanocomposite with a good structural interface and enhanced microwave absorption has been successfully and directly synthesized from graphene oxide via a facile hydrothermal approach. The permittivity of G–CdS nanocomposite presents triple dielectric relaxations by constructing a good structural G–CdS interface. The triple dielectric relaxations are critical to improve the microwave absorption of the G–CdS nanocomposite. Highlights: • Graphene–CdS (G–CdS) nanocomposite was directly synthesized from graphene oxide. • The G–CdS nanocomposite exhibits enhanced microwave absorption. • The permittivity of G–CdS nanocomposite presents triple dielectric relaxations. -- Abstract: The graphene–CdS (G–CdS) nanocomposite with enhanced microwave absorption was directly synthesized from graphene oxide (GO) via a facile hydrothermal approach, during which the formation of CdS nanoparticles and the reduction of GO occured simultaneously. The morphology, structure, microwave absorbing property, complex permittivity and permeability of G–CdS nanocomposite were systematically investigated by transmission electron microscope, X-ray diffraction and the coaxial line method. The complex permittivity of G–CdS nanocomposite presents triple dielectric relaxations with constructing a good structural graphene–CdS interface. The triple dielectric relaxations were critical to improve the microwave absorption of G–CdS nanocomposite. The G–CdS nanocomposite achieved a reflection loss below –10 dB in the frequency range of 5.2–18 GHz when adjusting the thicknesses from 2 to 5 mm, which was mainly ascribed to the proper electromagnetic matching of the CdS nanoparticles and graphene sheets, and the triple dielectric relaxations. The G–CdS nanocomposite is promising as a lightweight and wide-frequency microwave absorber

Hydrothermal synthesis of TiO2-ZnO-graphene nanocomposite towards photocatalytic and photovoltaic applications

Science.gov (United States)

Gayathri, S.; Jayabal, P.; Ramakrishnan, V.

2015-06-01

Titanium dioxide (TiO2) - Zinc oxide (ZnO) - Graphene (G) nanocomposite was successfully synthesized through facile hydrothermal method. The X-ray diffraction (XRD) pattern and the micro-Raman spectroscopic technique revealed the formation of TiO2-ZnO-Graphene (TZG) nanocomposite. The ZnO and TiO2 nanoparticles decorated graphene sheets were clearly noticeable in the Field Emission Scanning Electron Micrograph (FE-SEM). The UV-Visible absorption spectra clearly indicated that the formation of TZG nanocomposite enriched the absorption in the visible region. Hence, the prepared nanocomposite can be used as photocatalyst to remove organic dyes from water and as photoanode in the fabrication of dye sensitized solar cells (DSSCs).

Hydrothermal synthesis of TiO2-ZnO-graphene nanocomposite towards photocatalytic and photovoltaic applications

International Nuclear Information System (INIS)

Gayathri, S.; Jayabal, P.; Ramakrishnan, V.

2015-01-01

Titanium dioxide (TiO 2 ) - Zinc oxide (ZnO) - Graphene (G) nanocomposite was successfully synthesized through facile hydrothermal method. The X-ray diffraction (XRD) pattern and the micro-Raman spectroscopic technique revealed the formation of TiO 2 -ZnO-Graphene (TZG) nanocomposite. The ZnO and TiO 2 nanoparticles decorated graphene sheets were clearly noticeable in the Field Emission Scanning Electron Micrograph (FE-SEM). The UV-Visible absorption spectra clearly indicated that the formation of TZG nanocomposite enriched the absorption in the visible region. Hence, the prepared nanocomposite can be used as photocatalyst to remove organic dyes from water and as photoanode in the fabrication of dye sensitized solar cells (DSSCs)

Enhanced mechanical properties of hydrothermal carbamated cellulose nanocomposite film reinforced with graphene oxide.

Science.gov (United States)

Gan, Sinyee; Zakaria, Sarani; Syed Jaafar, Sharifah Nabihah

2017-09-15

Cellulose carbamate (CC) was synthesized via hydrothermal process and mixed with graphene oxide (GO) to form a homogeneous cellulose matrix nanocomposite films. The properties of CC/GO nanocomposite films fabricated using simple solution-mixing method with different GO loadings were studied. Transmission electron microscope analysis showed the exfoliation of self-synthesized GO nanosheets within the CC matrix. X-ray diffraction results confirmed the crystalline structure of CC/GO films as the CC/GO mass ratio increased from 100/0 to 100/4. The mechanical properties of CC/GO film were significantly improved as compared to neat CC film. From thermogravimetric analysis result, the introduction of GO enhanced the thermal stability and carbon yields. The 3D homogeneous porous structures of the CC/GO films were observed under Field emission scanning electron microscope. These improvements in nanocomposite film properties could be confirmed by Fourier transform infrared spectroscopy due to the strong and good interactions between CC and GO. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis and evaluation of lead telluride/bismuth antimony telluride nanocomposites for thermoelectric applications

Science.gov (United States)

Ganguly, Shreyashi; Zhou, Chen; Morelli, Donald; Sakamoto, Jeffrey; Uher, Ctirad; Brock, Stephanie L.

2011-12-01

Heterogeneous nanocomposites of p-type bismuth antimony telluride (Bi 2- xSb xTe 3) with lead telluride (PbTe) nanoinclusions have been prepared by an incipient wetness impregnation approach. The Seebeck coefficient, electrical resistivity, thermal conductivity and Hall coefficient were measured from 80 to 380 K in order to investigate the influence of PbTe nanoparticles on the thermoelectric performance of nanocomposites. The Seebeck coefficients and electrical resistivities of nanocomposites decrease with increasing PbTe nanoparticle concentration due to an increased hole concentration. The lattice thermal conductivity decreases with the addition of PbTe nanoparticles but the total thermal conductivity increases due to the increased electronic thermal conductivity. We conclude that the presence of nanosized PbTe in the bulk Bi 2- xSb xTe 3 matrix results in a collateral doping effect, which dominates transport properties. This study underscores the need for immiscible systems to achieve the decreased thermal transport properties possible from nanostructuring without compromising the electronic properties.

Nanoclay embedded mixed matrix PVDF nanocomposite membrane: Preparation, characterization and biofouling resistance

International Nuclear Information System (INIS)

Rajabi, Hamid; Ghaemi, Negin; Madaeni, Sayed S.; Daraei, Parisa; Khadivi, Mohammad Ali; Falsafi, Monir

2014-01-01

Highlights: • Nanocomposite membranes were prepared by addition of OMMT to PVDF membrane. • Addition of nanoclay considerably increased the hydrophilicity of PVDF membrane. • Nanocomposite membranes had higher water flux and antifouling properties. • Fouling of membranes blended with nanoclay (<4 wt.%) reduced. - Abstract: In this paper, nanocomposite PVDF/nanoclay membranes were prepared with addition of different concentrations of organically modified montmorillonite (OMMT) into the polymeric casting solution using combination of solution dispersion and phase inversion methods. Membranes were characterized by use of X-ray diffraction (XRD), water contact angle, scanning electron microscopy (SEM) and atomic force microscopy (AFM), and their performances were evaluated in terms of pure water flux and fouling parameters. The surface hydrophilicity of all nanocomposites markedly improved compared to nascent PVDF. In addition, XRD patterns revealed the formation of intercalated layers of mineral clays in PVDF matrix. SEM and AFM images showed that addition of OMMT resulted in nanocomposite membranes with thinner skin layer and higher porosity rather than PVDF membranes. Pure water flux of PVDF/OMMT membranes increased significantly (particularly for fabricated membranes by 4 and 6 wt.% OMMT) compared to that of PVDF membrane. Moreover, nanocomposite membranes showed the elevated antifouling properties, and flux recovery of nascent PVDF membranes increased from 51 to 72% with addition of 2 wt.% OMMT nanoparticles. These nanocomposite membranes also offered a remarkable reusability and durability against biofouling

Nanoclay embedded mixed matrix PVDF nanocomposite membrane: Preparation, characterization and biofouling resistance

Energy Technology Data Exchange (ETDEWEB)

Rajabi, Hamid [Membrane Research Centre, Department of Chemical Engineering, Razi University, Tagh Bostan, 67149 Kermanshah (Iran, Islamic Republic of); Department of Civil Engineering, Razi University, 67149 Kermanshah (Iran, Islamic Republic of); Ghaemi, Negin, E-mail: negin_ghaemi@kut.ac.ir [Department of Chemical Engineering, Kermanshah University of Technology, 67178 Kermanshah (Iran, Islamic Republic of); Madaeni, Sayed S. [Membrane Research Centre, Department of Chemical Engineering, Razi University, Tagh Bostan, 67149 Kermanshah (Iran, Islamic Republic of); Daraei, Parisa [Department of Chemical Engineering, Kermanshah University of Technology, 67178 Kermanshah (Iran, Islamic Republic of); Khadivi, Mohammad Ali [Friedrich-Alexander University, Erlangen-Nuremberg, Egerland Strasse 3, D-91058 Erlangen (Germany); Falsafi, Monir [Department of Chemistry, Faculty of Science, Razi University, 67149 Kermanshah (Iran, Islamic Republic of)

2014-09-15

Highlights: • Nanocomposite membranes were prepared by addition of OMMT to PVDF membrane. • Addition of nanoclay considerably increased the hydrophilicity of PVDF membrane. • Nanocomposite membranes had higher water flux and antifouling properties. • Fouling of membranes blended with nanoclay (<4 wt.%) reduced. - Abstract: In this paper, nanocomposite PVDF/nanoclay membranes were prepared with addition of different concentrations of organically modified montmorillonite (OMMT) into the polymeric casting solution using combination of solution dispersion and phase inversion methods. Membranes were characterized by use of X-ray diffraction (XRD), water contact angle, scanning electron microscopy (SEM) and atomic force microscopy (AFM), and their performances were evaluated in terms of pure water flux and fouling parameters. The surface hydrophilicity of all nanocomposites markedly improved compared to nascent PVDF. In addition, XRD patterns revealed the formation of intercalated layers of mineral clays in PVDF matrix. SEM and AFM images showed that addition of OMMT resulted in nanocomposite membranes with thinner skin layer and higher porosity rather than PVDF membranes. Pure water flux of PVDF/OMMT membranes increased significantly (particularly for fabricated membranes by 4 and 6 wt.% OMMT) compared to that of PVDF membrane. Moreover, nanocomposite membranes showed the elevated antifouling properties, and flux recovery of nascent PVDF membranes increased from 51 to 72% with addition of 2 wt.% OMMT nanoparticles. These nanocomposite membranes also offered a remarkable reusability and durability against biofouling.

Acetylene Gas-Sensing Properties of Layer-by-Layer Self-Assembled Ag-Decorated Tin Dioxide/Graphene Nanocomposite Film

OpenAIRE

Jiang, Chuanxing; Zhang, Dongzhi; Yin, Nailiang; Yao, Yao; Shaymurat, Talgar; Zhou, Xiaoyan

2017-01-01

This paper demonstrates an acetylene gas sensor based on an Ag-decorated tin dioxide/reduced graphene oxide (Ag–SnO2/rGO) nanocomposite film, prepared by layer-by-layer (LbL) self-assembly technology. The as-prepared Ag–SnO2/rGO nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectrum. The acetylene sensing properties were investigated using different working temperatures and gas concentrations. A...

Evaluation of hemocompatibility and in vitro immersion on microwave-assisted hydroxyapatite–alumina nanocomposites

International Nuclear Information System (INIS)

Radha, G.; Balakumar, S.; Venkatesan, Balaji; Vellaichamy, Elangovan

2015-01-01

This study reports the microwave-assisted synthesis and characterization of nHAp (nano-hydroxyapatite)–alumina composites. The crystalline phase and interaction of alumina with nHAp was analyzed using X-ray diffraction (XRD) and Raman microscopy analysis, respectively. High resolution transmission electron microscopy (HRTEM) micrographs exhibit morphological changes of nHAp composites with increasing alumina concentrations. Microhardness studies reveal the enhanced mechanical strength of nHAp10 and nHAp20 nanocomposites than pure nHAp. In vitro bioactivity of the nanocomposites was studied by immersing samples in simulated body fluid (Hank's solution) for 21 days. The surface of biomineralized samples were analyzed using field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). Hemolytic assay revealed acceptable compatibility for varying concentrations of all the samples. Cell proliferation assay was systematically investigated for 1 day and 3 days on Saos-2 osteoblast-like cell lines and it was found that nHAp nanocomposites improved the proliferation. - Highlights: • The microwave-assisted hydroxyapatite (nHAp)–alumina nanocomposites were prepared. • Structural and interaction between nHAp and alumina have been explored. • Increased alumina concentration enhanced mechanical strength of the nHAp. • Trace elements from SBF, incorporated on nHAp–alumina nanocomposite surface, were characterized by FESEM and EDX techniques. • Hemocompatibility of the samples were evaluated and the results are in accordance with ASTM standards

Evaluation of hemocompatibility and in vitro immersion on microwave-assisted hydroxyapatite–alumina nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Radha, G. [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy campus, Chennai - 600025 (India); Balakumar, S., E-mail: balasuga@yahoo.com [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy campus, Chennai - 600025 (India); Venkatesan, Balaji; Vellaichamy, Elangovan [Department of Biochemistry, University of Madras, Guindy campus, Chennai - 600025 (India)

2015-05-01

This study reports the microwave-assisted synthesis and characterization of nHAp (nano-hydroxyapatite)–alumina composites. The crystalline phase and interaction of alumina with nHAp was analyzed using X-ray diffraction (XRD) and Raman microscopy analysis, respectively. High resolution transmission electron microscopy (HRTEM) micrographs exhibit morphological changes of nHAp composites with increasing alumina concentrations. Microhardness studies reveal the enhanced mechanical strength of nHAp10 and nHAp20 nanocomposites than pure nHAp. In vitro bioactivity of the nanocomposites was studied by immersing samples in simulated body fluid (Hank's solution) for 21 days. The surface of biomineralized samples were analyzed using field emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDX). Hemolytic assay revealed acceptable compatibility for varying concentrations of all the samples. Cell proliferation assay was systematically investigated for 1 day and 3 days on Saos-2 osteoblast-like cell lines and it was found that nHAp nanocomposites improved the proliferation. - Highlights: • The microwave-assisted hydroxyapatite (nHAp)–alumina nanocomposites were prepared. • Structural and interaction between nHAp and alumina have been explored. • Increased alumina concentration enhanced mechanical strength of the nHAp. • Trace elements from SBF, incorporated on nHAp–alumina nanocomposite surface, were characterized by FESEM and EDX techniques. • Hemocompatibility of the samples were evaluated and the results are in accordance with ASTM standards.

Simple fabrication of reduced graphene oxide -few layer MoS2 nanocomposite for enhanced electrochemical performance in supercapacitors and water purification

Science.gov (United States)

Raghu, M. S.; Yogesh Kumar, K.; Rao, Srilatha; Aravinda, T.; Sharma, S. C.; Prashanth, M. K.

2018-05-01

Expelling of heavy metal ions into water resource systems is extremely hazardous to the environment. Adsorption is one of the most cost effective and potential methods to remove the heavy metal ions from the effluents. Therefore, an attempt has been made to study the adsorption of metal particles of Cd and Hg from aqueous solution by using reduced graphene oxide-molybdenum disulphide (rGO-MoS2) nanocomposites as adsorbents. The rGO-MoS2 composites were synthesized by following simple physical methods; which involve the mixing of dispersions of MoS2 and graphene oxide (GO) by sonication, followed by subsequent reduction with hydrazine hydrate. Characterization of the nanocomposites was performed by FESEM, TEM, EDAX, raman spectroscopy, XRD and BET surface area analysis. Electron microscopic images validate the presence of homogeneity in the synthesized nanocomposite. Batch adsorption experiments were used to scrutinizethe effect of an array of parameters like effect of pH, initial concentration of the metal ions, adsorbent dose, and contact time on the adsorption capacity of metal ions on rGO-MoS2 nanocomposites. The thorough examination of adsorbed isotherm and energy demonstrates the best fitting of the adsorption data with the 'Langmuir adsorption isotherm model' and follows the pseudo-second-order kinetic in active condition. The synthesized materials havealso been tested against Gram-positive and Gram-negative bacterial strains and have showcased promising antimicrobial activities. At the same time, the nanocomposites were evaluated for electrochemical performance in supercapacitors. The rGO-MoS2 nanocomposite demonstrates better capacitance (440 Fg-1) at 5 mvs-1 scan rate. The inimitable surface property of MoS2 and good electrical conductivity of rGO results show versatile usage and formidable performance as an adsorbent, antibacterial agent and electrode material for supercapacitors.

Dielectric properties of ligand-modified gold nanoparticles/SU-8 photopolymer based nanocomposites

KAUST Repository

Toor, Anju; So, Hongyun; Pisano, Albert P.

2017-01-01

This article reports the enhanced dielectric properties of a photodefinable nanocomposite material containing sub–10 nm coated metal nanoparticles (NPs). The surface morphology of the synthesized dodecanethiol-functionalized gold NPs was characterized using the transmission electron microscopy (TEM). We investigated the particle agglomeration and dispersion during the various stages of the nanocomposite synthesis using TEM. Physical properties such as dielectric permittivity and dielectric loss were measured experimentally. The dependence of dielectric permittivity and loss tangent on particle concentration and frequency was studied. Nanocomposite films showed an approximately three times enhancement in average dielectric constant over the polymer base value and an average dielectric loss of 0.09 at 1 kHz, at a filler loading of 10% w/w.

Dielectric properties of ligand-modified gold nanoparticles/SU-8 photopolymer based nanocomposites

KAUST Repository

Toor, Anju

2017-04-15

This article reports the enhanced dielectric properties of a photodefinable nanocomposite material containing sub–10 nm coated metal nanoparticles (NPs). The surface morphology of the synthesized dodecanethiol-functionalized gold NPs was characterized using the transmission electron microscopy (TEM). We investigated the particle agglomeration and dispersion during the various stages of the nanocomposite synthesis using TEM. Physical properties such as dielectric permittivity and dielectric loss were measured experimentally. The dependence of dielectric permittivity and loss tangent on particle concentration and frequency was studied. Nanocomposite films showed an approximately three times enhancement in average dielectric constant over the polymer base value and an average dielectric loss of 0.09 at 1 kHz, at a filler loading of 10% w/w.

Theoretical and Experimental Studies of New Polymer-Metal High-Dielectric Constant Nanocomposites

Science.gov (United States)

Ginzburg, Valeriy; Elwell, Michael; Myers, Kyle; Cieslinski, Robert; Malowinski, Sarah; Bernius, Mark

2006-03-01

High-dielectric-constant (high-K) gate materials are important for the needs of electronics industry. Most polymers have dielectric constant in the range 2 materials with K > 10 it is necessary to combine polymers with ceramic or metal nanoparticles. Several formulations based on functionalized Au-nanoparticles (R ˜ 5 -— 10 nm) and PMMA matrix polymer are prepared. Nanocomposite films are subsequently cast from solution. We study the morphology of those nanocomposites using theoretical (Self-Consistent Mean-Field Theory [SCMFT]) and experimental (Transmission Electron Microscopy [TEM]) techniques. Good qualitative agreement between theory and experiment is found. The study validates the utility of SCMFT as screening tool for the preparation of stable (or at least metastable) polymer/nanoparticle mixtures.

Visible-light-assisted SLCs template synthesis of sea anemone-like Pd/PANI nanocomposites with high electrocatalytic activity for methane oxidation in acidic medium

Science.gov (United States)

Tan, De-Xin; Wang, Yan-Li

2018-03-01

Sea anemone-like palladium (Pd)/polyaniline (PANI) nanocomposites were synthesized via visible-light-assisted swollen liquid crystals (SLCs) template method. The resulting samples were characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectrometer (EDS), x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), ultraviolet-visible (UV–vis) absorption spectroscopy and Fourier transform infrared (FT-IR) spectroscopy, respectively. The electrocatalytic properties of Pd/PANI nanocomposites modified glass carbon electrode (GCE) for methane oxidation were investigated by cycle voltammetry (CV) and chronoamperometry. Those dispersed sea anemone-like Pd/PANI nanocomposites had an average diameter of 320 nm. The obtained Pd nanoparticles with an average diameter of about 45 nm were uniformly distributed in PANI matrix. Sea anemone-like Pd/PANI nanocomposites exhibited excellent electrocatalytic activity and stability for oxidation of methane (CH4).

Synthesis of antimicrobial silver/hydroxyapatite nanocomposite by gamma irradiation

International Nuclear Information System (INIS)

Akhavan, A.; Sheikh, N.; Khoylou, F.; Naimian, F.; Ataeivarjovi, E.

2014-01-01

Silver nanoparticles (AgNPs) were synthesized through γ-irradiation reduction of silver ions into hydroxyapatite as a solid support. The formation of AgNPs incorporated in the hydroxyapatite composite was studied as a function of γ-irradiation doses. The X-ray diffraction and transmission electron microscopy (TEM) measurements showed the fabrication of face-centered cubic AgNPs with a mean diameter of about 39 nm at 20 kGy absorbed dose. When the absorbed dose increases from 20 to 40 kGy the size of AgNPs particles partially increases, while with increasing absorbed dose from 40 to 60 kGy the particle diameters decreases. In addition, the results of XRD analysis indicated that increasing of γ-irradiation doses from 20 to 40 kGy enhances the concentration of AgNPs, without inducing significant changes in degree of HA crystallinity. The antibacterial test study of samples against Escherichia coli indicated a significant enhancement in the antibacterial property of Ag/HA nanocomposites. - Highlights: • Silver/hydroxyapatite nanocomposites are synthesized through γ-irradiation method. • Ag/HA nanocomposites have good antibacterial properties. • Fabricated pure nanocomposites are suitable for medical and dental applications

Cure kinetics and chemorheology of EPDM/graphene oxide nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Allahbakhsh, Ahmad [Department of Polymer Engineering, Islamic Azad University, South Tehran Branch, 17776-13651 Tehran (Iran, Islamic Republic of); Mazinani, Saeedeh, E-mail: s.mazinani@aut.ac.ir [Amirkabir Nanotechnology Research Institute (ANTRI), Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Kalaee, Mohammad Reza [Department of Polymer Engineering, Islamic Azad University, South Tehran Branch, 17776-13651 Tehran (Iran, Islamic Republic of); Sharif, Farhad [Department of Polymer Engineering and Color Technology, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

2013-07-10

Graphical abstract: - Highlights: • Graphene oxide content and dispersion as effective parameters on cure kinetics. • Graphene oxide as an effective controlling factor of crosslink density. • Interaction of graphene oxide with curing system (ZnO) during curing process. - Abstract: In this study, the effect of graphene oxide on cure behavior of ethylene–propylene–diene rubber (EPDM) nanocomposite is studied. In this regard, the cure kinetics of nanocomposite is studied employing different empirical methods. The required activation energy of nth-order cure process shows about 160 kJ/mol increments upon 5 phr graphene oxide loading compared to 1 phr graphene oxide loading. However, the required activation energy is significantly reduced followed by incorporation of graphene oxide in nanocomposites compared to neat EPDM sample. Furthermore, the effect of graphene oxide on structural properties of nanocomposites during the cure process is studied using X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectrometry techniques. As the results show, graphene oxide interestingly affects the structure of zinc oxide during the vulcanization process. This behavior could be probably related to high tendency of zinc oxide to react with oxidized surface of graphene oxide.

An ultrasensitive electrochemical biosensor for glucose using CdTe-CdS core-shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle

International Nuclear Information System (INIS)

Gu Zhiguo; Yang Shuping; Li Zaijun; Sun Xiulan; Wang Guangli; Fang Yinjun; Liu Junkang

2011-01-01

Graphical abstract: We first reported an ultrasensitive electrochemical biosensor for glucose using CdTe-CdS core-shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle. Since promising their electrocatalytic synergy towards glucose was achieved, the biosensor showed high sensitivity (5762.8 nA nM -1 cm -2 ), low detection limit (S/N = 3) (3 x 10 -12 M) and fast response time (0.045 s). - Abstract: The paper reported an ultrasensitive electrochemical biosensor for glucose which was based on CdTe-CdS core-shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle. Since efficient electron transfer between glucose oxidase and the electrode was achieved, the biosensor showed high sensitivity (5762.8 nA nM -1 cm -2 ), low detection limit (S/N = 3) (3 x 10 -12 M), fast response time (0.045 s), wide calibration range (from 1 x 10 -11 M to 1 x 10 -8 M) and good long-term stability (26 weeks). The apparent Michaelis-Menten constant of the glucose oxidase on the medium, 5.24 x 10 -6 mM, indicates excellent bioelectrocatalytic activity of the immobilized enzyme towards glucose oxidation. Moreover, the effects of omitting graphene-gold nanocomposite, CdTe-CdS core-shell quantum dot and gold nanoparticle were also investigated. The result showed sensitivity of the biosensor is 7.67-fold better if graphene-gold nanocomposite, CdTe-CdS core-shell quantum dot and gold nanoparticle are used. This could be ascribed to improvement of the conductivity between graphene nanosheets due to introduction of gold nanoparticles, ultrafast charge transfer from CdTe-CdS core-shell quantum dot to graphene nanosheets and gold nanoparticle due to unique electrochemical properties of the CdTe-CdS core-shell quantum dot and good biocompatibility of gold nanoparticle for glucose oxidase. The biosensor is of best sensitivity in all glucose biosensors based on graphene nanomaterials up to

An ultrasensitive electrochemical biosensor for glucose using CdTe-CdS core-shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle

Energy Technology Data Exchange (ETDEWEB)

Gu Zhiguo; Yang Shuping [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China); Li Zaijun, E-mail: zaijunli@263.net [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China); Sun Xiulan [School of Food Science and Technology, Jiangnan University, Wuxi 214122 (China); Wang Guangli [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China); Fang Yinjun [Zhejiang Zanyu Technology Co., Ltd., Hangzhou 310009 (China); Liu Junkang [School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122 (China)

2011-10-30

Graphical abstract: We first reported an ultrasensitive electrochemical biosensor for glucose using CdTe-CdS core-shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle. Since promising their electrocatalytic synergy towards glucose was achieved, the biosensor showed high sensitivity (5762.8 nA nM{sup -1} cm{sup -2}), low detection limit (S/N = 3) (3 x 10{sup -12} M) and fast response time (0.045 s). - Abstract: The paper reported an ultrasensitive electrochemical biosensor for glucose which was based on CdTe-CdS core-shell quantum dot as ultrafast electron transfer relay between graphene-gold nanocomposite and gold nanoparticle. Since efficient electron transfer between glucose oxidase and the electrode was achieved, the biosensor showed high sensitivity (5762.8 nA nM{sup -1} cm{sup -2}), low detection limit (S/N = 3) (3 x 10{sup -12} M), fast response time (0.045 s), wide calibration range (from 1 x 10{sup -11} M to 1 x 10{sup -8} M) and good long-term stability (26 weeks). The apparent Michaelis-Menten constant of the glucose oxidase on the medium, 5.24 x 10{sup -6} mM, indicates excellent bioelectrocatalytic activity of the immobilized enzyme towards glucose oxidation. Moreover, the effects of omitting graphene-gold nanocomposite, CdTe-CdS core-shell quantum dot and gold nanoparticle were also investigated. The result showed sensitivity of the biosensor is 7.67-fold better if graphene-gold nanocomposite, CdTe-CdS core-shell quantum dot and gold nanoparticle are used. This could be ascribed to improvement of the conductivity between graphene nanosheets due to introduction of gold nanoparticles, ultrafast charge transfer from CdTe-CdS core-shell quantum dot to graphene nanosheets and gold nanoparticle due to unique electrochemical properties of the CdTe-CdS core-shell quantum dot and good biocompatibility of gold nanoparticle for glucose oxidase. The biosensor is of best sensitivity in all glucose

Synthesis and characterization of nanocomposites ZnO / polypyrrole for anti corrosive application

International Nuclear Information System (INIS)

Valenca, D.P.; Bouchonneau, N.; Vieira, M.R.S.; Alves, K.G.B.; Melo, C.P. de; Urtiga Filho, S.L.

2014-01-01

Nanoparticles of metal oxides and conductive polymers have been investigated as alternative additives in corrosion protection of oxidizable metals. In this hybrid nanocomposites work Polypyrrole-ZnO were synthesized and characterized as a potential application as industrial paint anti corrosive additive. The different steps of the synthesis and characterization of nanocomposites are described. The nanocomposites were obtained from the emulsion polymerization of aqueous solutions of pyrrole and sodium dodecyl sulfate containing ZnO nanoparticles dispersed in the mass. The nanoparticles were characterized by scanning electron microscopy and transmission, dynamic light scattering, diffraction of X-rays and techniques of infrared spectroscopy. From the characterization techniques, it was possible to determine the average size of nanoparticles of ZnO and ZnO-Polypyrrole. The peaks in the diffraction pattern of X-rays observed in the nanocomposite were the same as in ZnO, confirming the presence of ZnO in the composite. (author)

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

Structural, mechanical and electrical properties biopolymer blend nanocomposites derived from poly (vinyl alcohol)/cashew gum/magnetite

Science.gov (United States)

Ramesan, M. T.; Jayakrishnan, P.; Manojkumar, T. K.; Mathew, G.

2018-01-01

Blending of poly vinyl alcohol (PVA) and natural biopolymers such as cashew gum (CG) with magnetite (Fe3O4) nanoparticles has been a promising way for preparing bio-degradable polymeric blend nanocomposites. PVA/CG/Fe3O4 blend nanocomposites have been prepared by a simple solution casting technique using water as the green solvent. The characterization of blend nanocomposites has been carried out by using Fourier transform infrared, UV, x-ray diffraction (XRD), high resolution transmission electron microscopy, scanning electron microscopy (SEM), differential scanning calorimetry, thermogravimetric analysis, mechanical properties and electrical conductivity. The interaction between nanoparticles and the blend segments was confirmed from the shift in characteristic absorption peaks of nanocomposites compared to PVA/CG blend. XRD analysis has shown the presence of crystalline peaks of nanoparticles in the blend matrix. The uniform distribution of Fe3O4 nanoparticles in the blend was revealed by TEM and SEM. The strong interaction of nanoparticles with the blend has been confirmed by the increase in glass transition temperature resulting from the reduced flexibility of the blend nanocomposite compared to that of the blend system. An increase in thermal stability and tensile strength and reduction in elongation at break of nanocomposites have been noticed with the increasing loading of nanoparticles. The AC electrical conductivity, dielectric constant and dielectric loss of the nanocomposites have been found to be higher than that of the blend. Generally, it can be stated that the magnetite nanoparticles acts as a potential filler in the PVA/CG blend at 7 wt% loading, giving the best balance of properties.

Morphology and melt rheology of nylon 11/clay nanocomposites

NARCIS (Netherlands)

He, Xiaofeng; Yang, Jun; Zhu, Lianchao; Wang, Biao; Sun, Guangping; Lv, Pengfei; Phang, In Yee; Liu, Tianxi

2006-01-01

Nylon 11 (PA11)/clay nanocomposites have been prepared by melt-blending, followed by melt-extrusion through a capillary. Transmission electron microscopy shows that the exfoliated clay morphology is dominant for low nanofiller content, while the intercalated one is prevailing for high filler

Dipodal Silane-modified Nano Fe3O4/Polyurethane Magnetic Nanocomposites: Preparation and Characterization

Directory of Open Access Journals (Sweden)

Mir Mohammad Alavi Nikje

2016-01-01

Full Text Available Magnetic nanocomposites were prepared by incorporation of pure Fe3O4 and surface-modified Fe3O4 nanoparticles (dipodal silane-modified Fe3O4 into a polyurethane elastomer matrix by in situ polymerization method. In preparation of these magnetic nanocomposites, polycaprolactone (PCL was used as a polyester polyol. Because of dipole-dipole interactions between nanoparticles and a large surface area to volume ratio, the magnetic iron oxide nanoparticles tended to agglomerate. Furthermore, the most important challenge was to coat the surface of magnetic Fe3O4 nanoparticles in order to prepare well dispersed and stabilized Fe3O4 magnetic nanoparticles. It was observed that surface modification of Fe3O4 nanoparticles enhanced the dispersion of the nanoparticles in polyurethane matrices and allowed magnetic nanocomposites to be prepared with better properties. Surface modification of Fe3O4 was performed by dipodal silane synthesized based on 3-aminopropyltriethoxysilane (APTS and γ-glycidoxypropyl trimethoxysilane (GPTS. Dipodal silane-coated magnetic nanoparticles (DScMNPs were synthesized and incorporated into the polyurethane elastomer matrix as reinforcing agents. The formation of dipodal silane was investigated by Fourier transform infrared spectroscopy (FTIR, proton nuclear magnetic resonance spectroscopy (1H NMR and transmission electron microscopy (TEM. Characterization and study on the magnetic polyurethane elastomer nanocomposites were performed by FTIR, thermogravimetric analysis (TGA, scanning electron microscopy (SEM, vibrating sample magnetometry (VSM and dynamic mechanical thermal analysis (DMTA. The VSM results showed that the synthesized polyurethane elastomer nanocomposites had a superparamagnetic behavior. The TGA results showed that the thermal stability of dipodal silane-modified Fe3O4/PU nanocomposite was higher than that of Fe3O4/PU nanocomposite. This could be attributed to better dispersion and compatibility of dipodal silane

Structural and optical characterization of In{sub 2}O{sub 3}/PANI nanocomposite prepared by in-situ polymerization

Energy Technology Data Exchange (ETDEWEB)

Janeoo, Shashi; Sharma, Mamta, E-mail: mamta.phy85@gmail.com; Goswamy, J. [Department of Applied Sciences (Physics), UIET, Panjab University, Chandigarh-160 014 (India); Singh, Gurinder [Department of Applied Sciences (Physics), UIET, PUSSGSRC, Hoshiarpur (Punjab) (India)

2016-05-23

Polyaniline-indium oxide (In{sub 2}O{sub 3}/PANI) nanocomposite have been prepared by in-situ polymerization of aniline and as-synthesized In{sub 2}O{sub 3} nanoparticles. X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transformation infrared (FTIR) and UV/Vis spectroscopy techniques are used to investigate the structural and optical properties of In{sub 2}O{sub 3}/PANI nanocomposite. TEM analysis shows In{sub 2}O{sub 3} nanoparticles are embedded in PANI nanofibers. FTIR spectra show the good interactions between PANI nanofibers and In{sub 2}O{sub 3} nanoparticles. The band gap and electronic transitions in In{sub 2}O{sub 3}/PANI nanocomposite is determined by using UV/Vis spectra.

Bio-based hyperbranched thermosetting polyurethane/triethanolamine functionalized multi-walled carbon nanotube nanocomposites as shape memory materials.

Science.gov (United States)

Kalita, Hemjyoti; Karak, Niranjan

2014-07-01

Here, bio-based shape memory polymers have generated immense interest in recent times. Here, Bio-based hyperbranched polyurethane/triethanolamine functionalized multi-walled carbon nanotube (TEA-f-MWCNT) nanocomposites were prepared by in-situ pre-polymerization technique. The Fourier transform infrared spectroscopy and the transmission electron microscopic studies showed the strong interfacial adhesion and the homogeneous distribution of TEA-f-MWCNT in the polyurethane matrix. The prepared epoxy cured thermosetting nanocomposites exhibited enhanced tensile strength (6.5-34.5 MPa), scratch hardness (3.0-7.5 kg) and thermal stability (241-288 degrees C). The nanocomposites showed excellent shape fixity and shape recovery. The shape recovery time decreases (24-10 s) with the increase of TEA-f-MWCNT content in the nanocomposites. Thus the studied nanocomposites have potential to be used as advanced shape memory materials.

Euler European Libraries and Electronic Resources in Mathematical Sciences

CERN Document Server

The Euler Project. Karlsruhe

The European Libraries and Electronic Resources (EULER) Project in Mathematical Sciences provides the EulerService site for searching out "mathematical resources such as books, pre-prints, web-pages, abstracts, proceedings, serials, technical reports preprints) and NetLab (for Internet resources), this outstanding engine is capable of simple, full, and refined searches. It also offers a browse option, which responds to entries in the author, keyword, and title fields. Further information about the Project is provided at the EULER homepage.

Microstructure and Thermal Properties of Polypropylene/Clay Nanocomposites with TiCl4/MgCl2/Clay Compound Catalyst

Directory of Open Access Journals (Sweden)

Limei Wang

2015-01-01

Full Text Available Polypropylene (PP/clay nanocomposites were synthesized by in situ intercalative polymerization with TiCl4/MgCl2/clay compound catalyst. Microstructure and thermal properties of PP/clay nanocomposites were studied in detail. Fourier transform infrared (FTIR spectra indicated that PP/clay nanocomposites were successfully prepared. Both wide-angle X-ray diffraction (XRD and transmission electron microscopy (TEM examination proved that clay layers are homogeneously distributed in PP matrix. XRD patterns also showed that the α phase was the dominate crystal phase of PP in the nanocomposites. Thermogravimetric analysis (TGA examinations confirmed that thermal stability of PP/clay nanocomposites was markedly superior to pure PP. Differential scanning calorimetry (DSC scans showed that the melt temperature and the crystallinity of nanocomposites were slightly lower than those of pure PP due to crystals imperfections.

Synthesis of graphene oxide-copper molybdate (GO-CuM) nanocomposites for photocatalytic application

Science.gov (United States)

Singh, Gajendar; Bhargava, V. Sai; Sharma, Manu

2018-05-01

Transition metal molybdates (TMBs) MMoO4 (M=Ni, Cu, Fe, Zn, Co, etc.) based nanocomposites have been considered as remarkable materials in the field of electronics, optics, catalysis, supercapicitors and energy storage devices. Nanocomposites of TMBs with graphene oxide have also been chosen as an effective material in photocatalytic application. GO-CuM nanocomposites were synthesized by ultra-sonication method at RT, followed by reflux route for preparation of CuM and GO by modified Hemmer's method. As prepared nanocomposites were characterized using analytical techniques such as PXRD, SEM, FT-IR and UV-Visible spectroscopy. The enhanced photocatalytic activity of Methylene blue (MB) dye was observed by GO-CuM nanocomposites as compared to pure copper molybdate. GO-CuM nanocomposites show high photodegradation rate (0.094 min-1) whereas CuM was degraded only 30 % with the rate of 0.0029 min-1. The high photocatalytic efficiency is due to the presence of graphene oxide that helps to delay the charge recombination in photocatalytic reaction The effect of the different amount of graphene oxide on the photocatalytic activity of as prepared photocatalyst has also been investigated.

Third-order nonlinear optical response of Ag-CdSe/PVA hybrid nanocomposite

Energy Technology Data Exchange (ETDEWEB)

Tripathi, S.K.; Kaur, Ramneek; Kaur, Jaspreet; Sharma, Mamta [Panjab University, Department of Physics, Center of Advanced Study in Physics, Chandigarh (India)

2015-09-15

Hybrid nanocomposites of II-VI semiconductor nanoparticles are gaining great interest in nonlinear optoelectronic devices. Present work includes the characterization of CdSe polymer nanocomposite prepared by chemical in situ technique. From X-ray diffraction, the hexagonal wurtzite structure of nanoparticles has been confirmed with spherical morphology from transmission electron microscopy. Ag-CdSe hybrid polymer nanocomposite has been prepared chemically at different Ag concentrations. The presence of Ag in hybrid nanocomposite has been confirmed with energy-dispersive X-ray spectroscopy. The effect of varying Ag concentration on the linear and nonlinear optical properties of the nanocomposites has been studied. In linear optical parameters, the linear absorption coefficient, refractive index, extinction coefficient and optical conductivity have been calculated. The third-order nonlinear optical properties have been observed with open- and closed-aperture Z-scan technique. The large nonlinear refractive index ∝10{sup -5} cm{sup 2}/W with self-focusing behaviour is due to the combined effect of quantum confinement and thermo-optical effects. The enhanced nonlinearity with increasing Ag content is due to the surface plasmon resonance, which enhances the local electric field near the nanoparticle surface. Thus, Ag-CdSe hybrid polymer nanocomposite has favourable nonlinear optical properties for various optoelectronic applications. (orig.)

Third-order nonlinear optical response of Ag-CdSe/PVA hybrid nanocomposite

International Nuclear Information System (INIS)

Tripathi, S.K.; Kaur, Ramneek; Kaur, Jaspreet; Sharma, Mamta

2015-01-01

Hybrid nanocomposites of II-VI semiconductor nanoparticles are gaining great interest in nonlinear optoelectronic devices. Present work includes the characterization of CdSe polymer nanocomposite prepared by chemical in situ technique. From X-ray diffraction, the hexagonal wurtzite structure of nanoparticles has been confirmed with spherical morphology from transmission electron microscopy. Ag-CdSe hybrid polymer nanocomposite has been prepared chemically at different Ag concentrations. The presence of Ag in hybrid nanocomposite has been confirmed with energy-dispersive X-ray spectroscopy. The effect of varying Ag concentration on the linear and nonlinear optical properties of the nanocomposites has been studied. In linear optical parameters, the linear absorption coefficient, refractive index, extinction coefficient and optical conductivity have been calculated. The third-order nonlinear optical properties have been observed with open- and closed-aperture Z-scan technique. The large nonlinear refractive index ∝10 -5 cm 2 /W with self-focusing behaviour is due to the combined effect of quantum confinement and thermo-optical effects. The enhanced nonlinearity with increasing Ag content is due to the surface plasmon resonance, which enhances the local electric field near the nanoparticle surface. Thus, Ag-CdSe hybrid polymer nanocomposite has favourable nonlinear optical properties for various optoelectronic applications. (orig.)

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)

Effects of Electronic Information Resources Skills Training for Lecturers on Pedagogical Practices and Research Productivity

Science.gov (United States)

Bhukuvhani, Crispen; Chiparausha, Blessing; Zuvalinyenga, Dorcas

2012-01-01

Lecturers use various electronic resources at different frequencies. The university library's information literacy skills workshops and seminars are the main sources of knowledge of accessing electronic resources. The use of electronic resources can be said to have positively affected lecturers' pedagogical practices and their work in general. The…

Synthesis, characterization and photocatalytic activity of Fe2O3-TiO2 nanoparticles and nanocomposites

Directory of Open Access Journals (Sweden)

M. Ahmadi Golsefidi

2016-01-01

Full Text Available In this pepper Fe2O3 nanoparticles were synthesized via a fast microwave method. Then Fe2O3-TiO2 nanocomposites were synthesized by a sonochemical-assisted method. The prepared products were characterized by X-ray diffraction pattern, scanning electron microscopy and Fourier transform infrared spectroscopy. The photocatalytic behaviour of Fe2O3-TiO2 nanocomposites was evaluated using the degradation of Rhodamine B under ultra violet irradiation. The results show that nanocomposites have applicable magnetic and photocatalytic performance.

TiO₂ (rutile) embedded inulin--A versatile bio-nanocomposite for photocatalytic degradation of methylene blue.

Science.gov (United States)

Jayanthi Kalaivani, G; Suja, S K

2016-06-05

Inulin, a water soluble carbohydrate polymer, was extracted from Allium sativum L. by hot water diffusion method. A novel bio-nanocomposite was prepared by embedding TiO2 (rutile) onto the inulin matrix. The extracted inulin and the prepared bio-nanocomposite were characterized using UV-vis, FT-IR, XRD, SEM, TEM and TGA techniques. The photocatalytic activity of the bio-nanocomposite for the degradation of methylene blue was studied under UV illumination in batch mode experiment and was found to be twice as high as that of pristine TiO2. The kapp for inulin-TiO2 (0.0449 min(-1)) was higher than that for TiO2 (0.0325 min(-1)) which may be due to the synergistic action of inulin and TiO2. The stabilization of photo excited electron suppressed the electron-hole pair recombination thereby inducing the electrons and the holes to participate in the photo reduction and oxidation processes, respectively and enhancing the photocatalytic activity. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

Dry sliding wear behaviour of organo-modified montmorillonite filled epoxy nanocomposites using Taguchi's techniques

International Nuclear Information System (INIS)

Rashmi; Renukappa, N.M.; Suresha, B.; Devarajaiah, R.M.; Shivakumar, K.N.

2011-01-01

Highlights: → Successful fabrication of OMMT filled epoxy nanocomposites by high-shear mixing mehod. → Systematic tribological behaviour of the nanocomposites was made using Taguchi method. → Worn surface morphologies of the samples were discussed for different wear mechanisms. → Generation of wear data for sliding/bearing parts for different industries. -- Abstract: The aim of the research article is to study the dry sliding wear behaviour of epoxy with different wt.% of organo-modified montmorillonite (OMMT) filled nanocomposites. An orthogonal array (L 9 ) was used to investigate the influence of tribological parameters. The results indicate that the sliding distance emerges as the most significant factor affecting wear rate of epoxy nanocomposites. Experimental results showed that the inclusion of 5 wt.% OMMT nanofiller increased the wear resistance of the epoxy nanocomposite significantly. Furthermore, the worn surfaces of the samples were analyzed by scanning electron microscopy (SEM) to study the wear mechanisms and to correlate them with the wear test results.

A novel layered manganese oxide/poly(aniline-co-o-anisidine) nanocomposite and its application for electrochemical supercapacitor

International Nuclear Information System (INIS)

Yang Xiaofeng; Wang Gengchao; Wang Ruiyu; Li Xingwei

2010-01-01

A novel layered manganese oxide/poly(aniline-co-o-anisidine) nanocomposite [MnO 2 /P(An-co-oAs)] was successfully synthesized by a delamination/reassembling process using P(An-co-oAs) ionomer and layered manganese oxide in aqueous solution. This nanocomposite obtained was then characterized by Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), electron microscopy (SEM), and thermogravimetric (TG) analysis. X-ray diffraction and electron microscope analysis showed that the MnO 2 /P(An-co-oAs) nanocomposite had a lamellar structure with increasing interlayer spacing. The MnO 2 /P(An-co-oAs) nanocomposite exhibited substantially improved conductivity, which was near 100 times greater than that of its pristine MnO 2 (3.5 x 10 -7 S cm -1 ). The specific capacitance of the MnO 2 /P(An-co-oAs) nanocomposite reached 262 F g -1 in 1 M Na 2 SO 4 at a current density of 1 A g -1 , which was significantly higher than that of either of its two pristine materials [MnO 2 (182 F g -1 ) or P(An-co-oAs) (127 F g -1 )] owing to the synergic effect between the two pristine components. The fabrication mechanism of the nanocomposite was also proposed and discussed in this paper.

Fracture toughness of epoxy/multi-walled carbon nanotube nano-composites under bending and shear loading conditions

International Nuclear Information System (INIS)

Ayatollahi, M.R.; Shadlou, S.; Shokrieh, M.M.

2011-01-01

Research highlights: → Mode I and mode II fracture tests were conducted on epoxy/MWCNT nano-composites. → Addition of MWCNT to epoxy increased both K Ic and K IIc of nano-composites. → The improvement in K IIc was more pronounced than in K Ic . → Mode I and mode II fracture surfaces were studied by scanning electron microscopy. -- Abstract: The effects of multi-walled carbon nanotubes (MWCNTs) on the mechanical properties of epoxy/MWCNT nano-composites were studied with emphasis on fracture toughness under bending and shear loading conditions. Several finite element (FE) analyses were performed to determine appropriate shear loading boundary conditions for a single-edge notch bend specimen (SENB) and an equation was derived for calculating the shear loading fracture toughness from the fracture load. It was seen that the increase in fracture toughness of nano-composite depends on the type of loading. That is to say, the presence of MWCNTs had a greater effect on fracture toughness of nano-composites under shear loading compared with normal loading. To study the fracture mechanisms, several scanning electron microscopy (SEM) pictures were taken from the fracture surfaces. A correlation was found between the characteristics of fracture surface and the mechanical behaviors observed in the fracture tests.

Nanocomposites of polyamide 6/residual monomer with organic-modified montmorillonite and their nanofibers produced by electrospinning

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Cesar Augusto Gonçalves Beatrice

2012-08-01

Full Text Available Nanocomposites of an organic-modified montmorillonite (MMT and polyamide 6 (PA6 with a residual monomer were produced by melt mixing in a torque rheometer. By wide angle X-rays diffraction (WAXD, intercalated/exfoliated structures were observed in the PA6/MMT nanocomposites with 3 and 5 wt. (% of MMT; on the other hand, when 7 wt. (% of MMT was added, a nanocomposite with exfoliated structures was obtained due to the predominant linking reactions between the residual monomer and the "nanoclays" organic surfactant. Solutions of these PA6/MMT nanocomposites at 15, 17 and 20 wt. (% in formic acid were prepared. The 3 and 5 wt. (% nanocomposites were successfully electrospun; however, electrospinning of the 7 wt. (% nanocomposite was not possible. WAXD, scanning and transmission electron microscopy results showed that the 3 and 5 wt. (% nanofibers with average diameter between 80-250 nm had exfoliated structures. These results indicate that the high elongational forces developed during the electrospinning process changed the initial intercalated/exfoliated structure of the nanocomposites to an exfoliated one.

Chemical Synthesis, Characterization, and Biocompatibility Study of Hydroxyapatite/Chitosan Phosphate Nanocomposite for Bone Tissue Engineering Applications

Directory of Open Access Journals (Sweden)

Nabakumar Pramanik

2009-01-01

Full Text Available A novel bioanalogue hydroxyapatite (HAp/chitosan phosphate (CSP nanocomposite has been synthesized by a solution-based chemical methodology with varying HAp contents from 10 to 60% (w/w. The interfacial bonding interaction between HAp and CSP has been investigated through Fourier transform infrared absorption spectra (FTIR and x-ray diffraction (XRD. The surface morphology of the composite and the homogeneous dispersion of nanoparticles in the polymer matrix have been investigated through scanning electron microscopy (SEM and transmission electron microscopy (TEM, respectively. The mechanical properties of the composite are found to be improved significantly with increase in nanoparticle contents. Cytotoxicity test using murine L929 fibroblast confirms that the nanocomposite is cytocompatible. Primary murine osteoblast cell culture study proves that the nanocomposite is osteocompatible and highly in vitro osteogenic. The use of CSP promotes the homogeneous distribution of particles in the polymer matrix through its pendant phosphate groups along with particle-polymer interfacial interactions. The prepared HAp/CSP nanocomposite with uniform microstructure may be used in bone tissue engineering applications.

Study on the mechanical properties of a HMS-PP nanocomposite with a Brazilian bentonite

International Nuclear Information System (INIS)

Fermino, D.M.; Parra, D.F.; Lugao, A.B.; Oliani, W.L.; Valenzuela-Diaz, F.R.

2010-01-01

This work concerns to the study of the mechanical behavior of the nanocomposite HMSPP - Polypropylene High Melt Strength (obtained at a dose of 12.5 kGy) and a bentonite clay Brazilian Paraiba (PB), known as 'Chocolate' in concentrations of 5 and 10% by weight, comparison of to one American Clay, cloisite 20A nanocomposite was done. Agent compatibilizer polypropylene-graft, known as maleic anhydride (PP-g-AM) was addict 3% concentration thought technique melt intercalation using a twin-screw extruder and the specimens were prepared by injection process. The mechanical behavior was evaluated by strength, flexural strength and impact tests. The morphology of the nanocomposites was studied by the technique of Scanning Electron Microscopy (SEM), while the organophilic bentonite and nanocomposites were characterized by X-ray diffraction (XRD) and infrared (FTIR). (author)

The formation of hollow poly(methyl methacrylate)/multiwalled carbon nanotube nanocomposite cylinders by microwave irradiation

International Nuclear Information System (INIS)

Wang Huan; Hu Xijun; Ka Ming Ng; Feng Jiyun

2009-01-01

Poly(methyl methacrylate) (PMMA)/multiwalled carbon nanotube (MWCNT) nanocomposite particles with 1, 2 and 4 wt% of MWCNTs were prepared by mechanical grinding of PMMA and MWCNT powders in a mortar at room temperature. Both scanning electron microscopy and Raman scattering characterizations revealed that these nanocomposite particles consist of a PMMA core and a MWCNT shell. The PMMA/MWCNT nanocomposite particles were used to fabricate the corresponding nanocomposites in the form of a hollow cylinder with various diameters and heights under 700 W microwave irradiation within 1 min. A mechanism for the fast microwave assisted forming process is proposed. These experimental results may lead to a new technology for forming hollow polymeric articles that is different from the conventional injection and blowing process.

Synthesis, characterization, biocompatibility of hydroxyapatite-natural polymers nanocomposites for dentistry applications.

Science.gov (United States)

Chung, Jin-Hwan; Kim, Young Kyung; Kim, Kyo-Han; Kwon, Tae-Yub; Vaezmomeni, Seyede Ziba; Samiei, Mohammad; Aghazadeh, Marzyeh; Davaran, Soodabeh; Mahkam, Mehrdad; Asadi, Ghale; Akbarzadeh, Abolfazl

2016-01-01

Hydroxyapatite (HA), the main mineral component of bones and teeth, was synthesized by using the reaction between calcium nitrate tetrahydrate Ca(NO3)2∙4H2O and diammonium hydrogen phosphate (NH4)2HPO4 (DAHP) with a chemical precipitation method. The objective of this study is to utilize novel inorganic-organic nanocomposites for biomedical applications. HA is an inorganic component (75% w) and chitosan, alginate and albumin (Egg white) are organic components of nanocomposites (25% w). Nanocomposites were prepared in deionized water solutions, at room temperature, using a mechanical and magnetic stirrer for 48 h. The microstructure and morphology of sintered n-HAP were tested at different preheating temperature and laser sintering speed with scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR).

Impact of nanoclay dispersed phenol formaldehyde/fumed silica nanocomposites on physico-mechanical and thermal properties

Science.gov (United States)

Lai, Josephine Chang Hui; Rahman, Md. Rezaur; Hamdan, Sinin

2017-12-01

In this study, the physical, mechanical and thermal properties of phenol formaldehyde/fumed silica/nanoclay (PF/FS/clay) nanocomposites were investigated. PF/FS/clay nanocomposites were prepared via condensation polymerization method and the effect of different clays as compatibilizers were subsequently investigated. The properties of nanocomposites were characterized through Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA) and tensile test. FT-IR results confirmed the condensation polymerization and the formation of nanocomposites. SEM result revealed that the surface-modified clay (1.34TCN) had better compatibility with PF/FS matrix compared to surface-modified clay (1.28E), clay (1.30E) and clay (1.31PS). Besides, clay (1.34TCN)-loaded nanocomposites showed better surface morphology among all the nanocomposites. Furthermore, PF/FS/clay (1.34TCN) nanocomposite exhibited better tensile strength and modulus up to 68% due to the strong interfacial bonding between the polymer matrix and fillers. Thermal stability of PF/FS/clay (1.34TCN) nanocomposite showed the highest weight percent loss at the final degradation stage with higher activation energy. Overall, this study proved that clay (1.34TCN) was the most suitable to be introduced in PF/FS matrix.

Hydrothermal synthesis of TiO{sub 2}-ZnO-graphene nanocomposite towards photocatalytic and photovoltaic applications

Energy Technology Data Exchange (ETDEWEB)

Gayathri, S., E-mail: s.gayathri1010@gmail.com; Jayabal, P. [Department of Laser Studies, School of Physics, Madurai Kamaraj University, Madurai-625021 (India); Ramakrishnan, V. [Department of Laser Studies, School of Physics, Madurai Kamaraj University, Madurai-625021 (India); Indian Institute of Science Education and Research Thiruvananthapuram, Thiruvananthapuram-695016 (India)

2015-06-24

Titanium dioxide (TiO{sub 2}) - Zinc oxide (ZnO) - Graphene (G) nanocomposite was successfully synthesized through facile hydrothermal method. The X-ray diffraction (XRD) pattern and the micro-Raman spectroscopic technique revealed the formation of TiO{sub 2}-ZnO-Graphene (TZG) nanocomposite. The ZnO and TiO{sub 2} nanoparticles decorated graphene sheets were clearly noticeable in the Field Emission Scanning Electron Micrograph (FE-SEM). The UV-Visible absorption spectra clearly indicated that the formation of TZG nanocomposite enriched the absorption in the visible region. Hence, the prepared nanocomposite can be used as photocatalyst to remove organic dyes from water and as photoanode in the fabrication of dye sensitized solar cells (DSSCs)

Cost-efficient high performance polyetheretherketone/expanded graphite nanocomposites with high conductivity for EMI shielding application

Energy Technology Data Exchange (ETDEWEB)

Goyal, R.K., E-mail: rkgoyal72@yahoo.co.in

2013-10-01

The cost efficient expanded graphite (EG) filled polyetheretherketone (PEEK) nanocomposites were prepared by hot pressing, which exhibited an electrical conductivity percolation threshold of 1.5 wt%. The electrical conductivity of the 1.5 wt% nanocomposite increased approximately eleven orders of magnitude than that of pure PEEK. The conductivities of 5 wt% and 10 wt% nanocomposites were increased to about 3.24 S cm{sup −1} and 12.3 S cm{sup −1}, respectively. Scanning electron microscope showed 3-dimensional conductive network of EG across the PEEK matrix. The significant increase in electrical conductivity of the nanocomposites leads to the tremendous increase in electromagnetic interference shielding effectiveness. - Highlights: • A sharp increase in conductivity was observed at 1.5 wt% EG content. • The conductivity of 10 wt% nanocomposites is about 12.3 S cm{sup −1}. • This conductivity is the highest among reported value in literature.

EPR and rheological study of hybrid interfaces in gold-clay-epoxy nanocomposites.

Science.gov (United States)

Angelov, Verislav; Velichkova, Hristiana; Ivanov, Evgeni; Kotsilkova, Rumiana; Delville, Marie-Hélène; Cangiotti, Michela; Fattori, Alberto; Ottaviani, Maria Francesca

2014-11-11

With the aim to obtain new materials with special properties to be used in various industrial and biomedical applications, ternary "gold-clay-epoxy" nanocomposites and their nanodispersions were prepared using clay decorated with gold nanoparticles (AuNPs), at different gold contents. Nanocomposites structure was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Rheology and electron paramagnetic resonance (EPR) techniques were used in order to evaluate the molecular dynamics in the nanodispersions, as well as dynamics at interfaces in the nanocomposites. The percolation threshold (i.e., the filler content related to the formation of long-range connectivity of particles in the dispersed media) of the gold nanoparticles was determined to be ϕp = 0.6 wt % at a fixed clay content of 3 wt %. The flow activation energy and the relaxation time spectrum illustrated the presence of interfacial interactions in the ternary nanodispersions around and above the percolation threshold of AuNPs; these interfacial interactions suppressed the global molecular dynamics. It was found that below ϕp the free epoxy polymer chains ratio dominated over the chains attracted on the gold surfaces; thus, the rheological behavior was not significantly changed by the presence of AuNPs. While, around and above ϕp, the amount of the bonded epoxy polymer chains on the gold surface was much higher than that of the free chains; thus, a substantial increase in the flow activation energy and shift in the spectra to higher relaxation times appeared. The EPR signals of the nanocomposites depended on the gold nanoparticle contents and the preparation procedure thus providing a fingerprint of the different nanostructures. The EPR results from spin probes indicated that the main effect of the gold nanoparticles above ϕp, was to form a more homogeneous, viscous and polar clay-epoxy mixture at the nanoparticle surface. The knowledge

Nonlinear optical spectroscopy of isotropic and anisotropic metallic nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Fernandez-Hernandez, R C; Gleason-Villagran, R; Cheang-Wong, J C; Crespo-Sosa, A; Rodriguez-Fernandez, L; Lopez-Suarez, A; Oliver, A; Reyes-Esqueda, J A [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Mexico, D. F. 04510 (Mexico); Torres-Torres, C [Seccion de Estudios de Posgrado e Investigacion, ESIME-Zacatenco, Instituto Politecnico Nacional, Mexico, D. F. 07338 (Mexico); Rangel-Rojo, R, E-mail: reyes@fisica.unam.mx [CICESE/Depto. de Optica, A.P. 360, Ensenada, B. C. 22860 (Mexico)

2011-01-01

In this work, we studied the nonlinear absorption and refraction of isotropic and anisotropic metallic nanocomposites, which consist of Au and Ag nanoparticles (NPs) embedded in matrices of SiO{sub 2}. We performed this study at different wavelengths using the Z-scan technique in the picosecond regime. The wavelengths were selected accordingly to the absorption spectra of the nanocomposites, choosing wavelengths into the inter- and intra-band transitions regions, including the surface plasmon (SP) resonance, as well as in the transparent region. For the anisotropic nanocomposites, the polarization and the incident angle were varied in order to evaluate the different components of the third order susceptibility tensor, {chi}{sup (3)}. We observed dramatic changes of sign for both, nonlinear refraction and absorption, when passing from Au to Ag and/or varying the wave length. The results accentuate the importance of the hot-electrons contribution to the nonlinear optical response at this temporal regime, when compared to inter-band and intra-band transitions contributions.

Nonlinear optical spectroscopy of isotropic and anisotropic metallic nanocomposites

International Nuclear Information System (INIS)

Fernandez-Hernandez, R C; Gleason-Villagran, R; Cheang-Wong, J C; Crespo-Sosa, A; Rodriguez-Fernandez, L; Lopez-Suarez, A; Oliver, A; Reyes-Esqueda, J A; Torres-Torres, C; Rangel-Rojo, R

2011-01-01

In this work, we studied the nonlinear absorption and refraction of isotropic and anisotropic metallic nanocomposites, which consist of Au and Ag nanoparticles (NPs) embedded in matrices of SiO 2 . We performed this study at different wavelengths using the Z-scan technique in the picosecond regime. The wavelengths were selected accordingly to the absorption spectra of the nanocomposites, choosing wavelengths into the inter- and intra-band transitions regions, including the surface plasmon (SP) resonance, as well as in the transparent region. For the anisotropic nanocomposites, the polarization and the incident angle were varied in order to evaluate the different components of the third order susceptibility tensor, χ (3) . We observed dramatic changes of sign for both, nonlinear refraction and absorption, when passing from Au to Ag and/or varying the wave length. The results accentuate the importance of the hot-electrons contribution to the nonlinear optical response at this temporal regime, when compared to inter-band and intra-band transitions contributions.

Fabrication and physical properties of transparent poly (methyl-methacrylate)-layered silicate nanocomposites

Science.gov (United States)

Vasiliu, Elena

Transparent polymer nanocomposites have promising potential for protective coating applications with improved surface resistance, higher temperature performance and low gas permeability for containers and films. Extremely thin protective layers are required for improved performance of various electronic devices in aviation, aerospace and medical equipment as well as for lenses and fiber optics in optical communications. This research study developed a method for fabricating optically transparent nanocomposites of poly(methyl-methacrylate)(PMMA) and a commercial organically-modified layered silicate CloisiteRTM 6A (C6A). The nanocomposites were produced by dispersing C6A and PMMA separately in a common solvent xylene followed by mixing the two solutions by mechanical stirring and/or ultrasonic agitation and then removing the solvent by evaporation. Processing conditions such as the mixing methods and times and the rates of solvent removal were investigated in order to achieve a high degree of dispersion and exfoliation of C6A in the polymer matrix and produce a nanocomposite material with high optical transparency. Small-angle x-ray scattering (SAXS) was used to monitor the morphology of the C6A after each processing step. Thin films of PMMA/C6A nanocomposites were produced by casting and spraying. SAXS results suggest that C6A was partially exfoliated in the composite material with an average of 2 to 3 platelets per crystallite. Transmission electron microscopy (TEM) confirmed the existence of both exfoliated and intercalated C6A in PMMA. One mm thick discs were obtained by molding the sprayed films. The optical transmission of the nanocomposite films and discs was measured with an UV/VIS spectrometer. The spectroscopic results served to identify the best process for producing PMMA-C6A films of high optical transparency. Even the nanocomposite films containing up to 20 wt.% C6A prepared by this process exhibited optical transmittance in the range of 80 to 90

Use of Brazilian clay in nylon 6 with different molecular weight nanocomposites

International Nuclear Information System (INIS)

Araujo, Edcleide Maria; Paz, Rene Anisio; Melo, Tomas Jeferson Alves; Leite, Amanda Melissa Damiao; Barbosa, Renata; Ito, Edson Noriyuki

2009-01-01

The effect of nylon 6 (Ny6) molecular weight on the development of polymer/layered silicates nanocomposites prepared by the melt intercalation technique was studied in this work. The nylon6/organoclay nanocomposites were prepared in the counter-rotational twin screw extruder. The results of torque rheometry showed that the presence of organoclay in the nylon 6 increased the torque. The results of X-ray diffraction (XRD) and transmission electron microscopy (TEM) showed exfoliated and/or partially exfoliated structures. (author)

On the Injection Molding Processing Parameters of HDPE-TiO2 Nanocomposites

Science.gov (United States)

Mourad, Abdel-Hamid I.; Mozumder, Mohammad Sayem; Mairpady, Anusha; Pervez, Hifsa; Kannuri, Uma Maheshwara

2017-01-01

In recent years, the development and use of polymeric nanocomposites in creating advanced materials has expanded exponentially. A substantial amount of research has been done in order to design polymeric nanocomposites in a safe and efficient manner. In the present study, the impact of processing parameters, such as, barrel temperature, and residence time on the mechanical and thermal properties of high density polyethylene (HDPE)-TiO2 nanocomposites were investigated. Additionally, scanning electron microscopy and X-ray diffraction spectroscopy were used to analyze the dispersion, location, and phase morphology of TiO2 on the HDPE matrix. Mechanical tests revealed that tensile strength of the fabricated HDPE-TiO2 nanocomposites ranged between 22.53 and 26.30 MPa, while the Young’s modulus showed a consistent increase as the barrel temperature increased from 150 °C to 300 °C. Moreover, the thermal stability decreased as the barrel temperature increased. PMID:28772444

Synthesis and characterization of graphene quantum dots/cobalt ferrite nanocomposite

Science.gov (United States)

Ramachandran, Shilpa; Sathishkumar, M.; Kothurkar, Nikhil K.; Senthilkumar, R.

2018-02-01

A facile method has been developed for the synthesis of a graphene quantum dots/cobalt ferrite nanocomposite. Graphene quantum dots (GQDs) were synthesized by a simple bottom-up method using citric acid, followed by the co-precipitation of cobalt ferrite nanoparticles on the graphene quantum dots. The morphology, structural analysis, optical properties, magnetic properties were investigated using transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-vis absorption spectroscopy, fluorescence spectroscopy, vibrating sample magnetometry (VSM) measurements. The synthesized nanocomposite showed good fluorescence and superparamagnetic properties, which are important for biomedical applications.

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

Liquid-Phase Co-Exfoliated Graphene/MoS2 Nanocomposite for Methanol Gas Sensing.

Science.gov (United States)

Zhang, Shao-Lin; Yue, Hongyan; Liang, Xishuang; Yang, Woo-Chul

2015-10-01

We developed an efficient method to co-exfoliate graphite and MoS2 to fabricate graphene/MoS2 nanocomposite. The size, morphology, and crystal structure of the graphene/MoS2 nanocomposite were carefully examined. The as-prepared graphene/MoS2 nanocomposite was fabricated into thin film sensor by a facile drop casting method and tested with methanol gas in various concentrations. The sensitivity, response time, and repeatability of the graphene/MoS2 nanocomposite sensor towards methanol gas were systematically investigated. A pure MoS2 based thin film sensor was also prepared and compared with the nanocomposite sensor to better understand the synergetic effect in the sensing performance. Our research demonstrated that compositing MoS2 with graphene could overcome the shortcoming of MoS2 as a sensor material and bring in a promising gas-sensing performance with a quicker response/recovery time and an enhanced sensitivity. Moreover, this composited material with a distinct structure and an excellent electronic property is expected to have potential application in various fields, such as optoelectronic.

Sonochemical synthesis and high lithium storage properties of ordered Co/CMK-3 nanocomposites

Science.gov (United States)

Qiao, Hui; Xia, Zhaokang; Liu, Yanhua; Cui, Rongrong; Fei, Yaqian; Cai, Yibing; Wei, Qufu; Yao, Qingxia; Qiao, Qiquan

2017-04-01

A novel ordered Co/CMK-3 nanocomposite was successfully synthesized via the sonochemical method followed by carbonization process. The ordered Co/CMK-3 nanocomposite were characterized by X-ray diffraction, transmission electron microscopy and N2 adsorption-desorption analysis techniques. The lithium storage properties shows that the Co/CMK-3 nanocomposites exhibit a large reversible capacity and good cycle stability with the capacity of 720 mAh g-1 after 50 cycles at a current rate of 50 mA g-1, much higher than that of original CMK-3 electrode. The Co/CMK-3 nanocomposites also demonstrates an excellent rate capability with capacity of 479 mAh g-1 even at a current density of 1000 mA g-1 after 50 cycles. The improved lithium storage properties of ordered Co/CMK-3 nanocomposites can be attributed to the CMK-3 could restrain the aggregation of Co nanoparticles, the large surface area of the mesopores in which the Co nanoparticles are formed, as well as presence of Co which played the role of catalyst could promote the lithium storage reaction.

Study of modified polypropylene nanocomposites by gamma irradiation with addition of cloisite clay

International Nuclear Information System (INIS)

Komatsu, Luiz G.H.; Oliani, Washington L.; Parra, Duclerc F.; Lugao, Ademar B.

2011-01-01

Nanomaterials, and, in particular, nanoreinforcements for polymer composites have been the subject of intense research, development and commercialization. Clay-containing polymeric nanocomposites (CPNCs) are used as either functional or structural materials, large-volume CPNCs with a commodity or engineering polymer as the matrix, where the mechanical behavior is the main concern (followed by gas-vapor barrier properties, flammability, etc.). This work concerns to the study of the mechanical, thermal and morphological behavior nanocomposite, (HMSPP) Polypropylene High Melt Strength (obtained at dose of 12.5 kGy) and addition of 5 and 10 wt% of organoclay with Cloisite 20A nanocomposite. Agent compatibilizer polypropylene-graft, (PP-g-AM) was added at 3% concentration and the clay was dispersed through melt intercalation technique using a twin-screw extruder). We observed an increase in traction rupture. The mechanical behavior was evaluated by strength, the thermal behavior were evaluated by the technique of differential scanning calorimetry, the morphology of the nanocomposites was studied by scanning electron microscopy, melt flow index and Fourier transformed infrared spectroscopy in nanocomposites Cloisite 20 A at 10% wt. (author)

Grafting of polyethylenimine onto cellulose nanofibers for interfacial enhancement in their epoxy nanocomposites.

Science.gov (United States)

Zhao, Jiangqi; Li, Qingye; Zhang, Xiaofang; Xiao, Meijie; Zhang, Wei; Lu, Canhui

2017-02-10

Cellulose nanofibers (CNFs) were surface-modified with polyethyleneimine (PEI), which brought plentiful amine groups on the surface of CNFs, leading to a reduced hydrogen bond density between CNFs and consequently less CNFs agglomerates. The amine groups could also react with the epoxy as an effective curing agent that could increase the interfacial crosslinking density and strengthen interfacial adhesion. The tensile strength and Young's modulus of CNFs-PEI/Epoxy nanocomposites were 88.1% and 237.6% higher than those of neat epoxy, respectively. The tensile storage modulus of the nanocomposites also increased significantly at the temperature either below or above the Tg. The coefficient of thermal expansion for the CNFs-PEI/Epoxy nanocomposites was 22.2ppmK -1 , much lower than that of the neat epoxy (88.6ppmK -1 ). In addition, the thermal conductivity of the nanocomposites was observed to increase as well. The exceptional and balanced properties may provide the nanocomposites promising applications in automotive, construction and electronic devices. Copyright © 2016 Elsevier Ltd. All rights reserved.

Graphene/CuS/ZnO hybrid nanocomposites for high performance photocatalytic applications

International Nuclear Information System (INIS)

Varghese, Jini; Varghese, K.T.

2015-01-01

We herein report a novel, high performance ternary nanocomposite composed of Graphene doped with nano Copper Sulphide and Zinc Oxide nanotubes (GCZ) for photodegradation of organic pollutants. Investigations were made to estimate and compare the Methyl Orange dye (MO) degradation using GCZ, synthesized pristine Graphene (Gr) and Graphene–ZnO hybrid nanocomposite (GZ) under UV light irradiations. The synthesis of nanocomposites involves the simple ultra-sonication and mixing methods. The nanocomposites were characterized using transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), Raman spectroscopy, UV–vis absorption spectroscopy and Brunauer–Emmett–Teller (BET) surface area method. The as synthesized GCZ shows better surface area, porosity and band gap energy than as synthesized Gr and GZ. The photocatalytic degradation of methyl orange dye follows as Gr  > GZ due to the stronger adsorbability, large number of photo induced electrons and highest inhibition of charge carrier's recombination of GCZ. The kinetic investigation demonstrates that dye degradation exhibit the pseudo first order kinetic model with rate constant 0.1322, 0.049 and0.0109 min"−"1 corresponding to GCZ, GZ and Gr. The mechanism of dye degradation in presence of photocatalyst is also discussed. This study confirms that GCZ is a more promising material for high performance catalytic applications especially in the dye waste water purification. - Highlights: • Graphene–CuS–ZnO hybrid composites show better surface area, porosity and adsorbability. • CuS–ZnO hybrid nanostructure highly enhanced the photocatalytic activity of Graphene. • Graphene–CuS–ZnO hybrid composites show superior photocatalytic efficiency, rate constant and quantum yield.

Graphene/CuS/ZnO hybrid nanocomposites for high performance photocatalytic applications

Energy Technology Data Exchange (ETDEWEB)

Varghese, Jini, E-mail: jini.nano@gmail.com; Varghese, K.T., E-mail: ktvscs@gmail.com

2015-11-01

We herein report a novel, high performance ternary nanocomposite composed of Graphene doped with nano Copper Sulphide and Zinc Oxide nanotubes (GCZ) for photodegradation of organic pollutants. Investigations were made to estimate and compare the Methyl Orange dye (MO) degradation using GCZ, synthesized pristine Graphene (Gr) and Graphene–ZnO hybrid nanocomposite (GZ) under UV light irradiations. The synthesis of nanocomposites involves the simple ultra-sonication and mixing methods. The nanocomposites were characterized using transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), Raman spectroscopy, UV–vis absorption spectroscopy and Brunauer–Emmett–Teller (BET) surface area method. The as synthesized GCZ shows better surface area, porosity and band gap energy than as synthesized Gr and GZ. The photocatalytic degradation of methyl orange dye follows as Gr <<< GCZ >> GZ due to the stronger adsorbability, large number of photo induced electrons and highest inhibition of charge carrier's recombination of GCZ. The kinetic investigation demonstrates that dye degradation exhibit the pseudo first order kinetic model with rate constant 0.1322, 0.049 and0.0109 min{sup −1} corresponding to GCZ, GZ and Gr. The mechanism of dye degradation in presence of photocatalyst is also discussed. This study confirms that GCZ is a more promising material for high performance catalytic applications especially in the dye waste water purification. - Highlights: • Graphene–CuS–ZnO hybrid composites show better surface area, porosity and adsorbability. • CuS–ZnO hybrid nanostructure highly enhanced the photocatalytic activity of Graphene. • Graphene–CuS–ZnO hybrid composites show superior photocatalytic efficiency, rate constant and quantum yield.

A comparative approach to synthesis and sintering of alumina/yttria nanocomposite powders using different precipitants

Energy Technology Data Exchange (ETDEWEB)

Kafili, G. [Department of Nanotechnology Engineering, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan, 81746-73441 (Iran, Islamic Republic of); Movahedi, B., E-mail: b.movahedi@ast.ui.ac.ir [Department of Nanotechnology Engineering, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan, 81746-73441 (Iran, Islamic Republic of); Milani, M. [Faculty of Advanced Materials and Renewable Energy Research Center, Tehran (Iran, Islamic Republic of)

2016-11-01

Alumina/yttria nanocomposite powder as an yttrium aluminum garnet (YAG) precursor was synthesized via partial wet route using urea and ammonium hydrogen carbonate (AHC) as precipitants, respectively. The products were characterized using X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and energy dispersive spectroscopy. The use of urea produced very tiny spherical Y-compounds with chemical composition of Y{sub 2}(CO{sub 3}){sub 3}·nH{sub 2}O, which were attracted to the surface of alumina nanoparticles and consequently, a core-shell structure was obtained. The use of ammonium hydrogen carbonate produced sheets of Y-compounds with chemical composition of Y(OH)CO{sub 3} covering the alumina nanoparticles. A fine-grained YAG ceramic (about 500 nm), presenting a non-negligible transparency (45% RIT at IR range) was obtained by the spark plasma sintering (SPS) of alumina-yttria nanocomposite synthesized in the urea system. This amount of transmission was obtained by only the sintering of the powder specimen without any colloidal forming process before sintering or adding any sintering aids or dopant elements. However, by spark plasma sintering of alumina-yttria nanocomposite powder synthesized in AHC system, an opaque YAG ceramic with an average grain size of 1.2 μm was obtained. - Highlights: • Urea proved to be an appropriate precipitant for obtaining a core-shell alumina/yttria nanocomposite. • Alumina/yttria nanocomposite powders with more appropriate morphology and highly sinterability. • A fine-grained YAG ceramic was obtained by SPS of alumina-yttria nanocomposite.

Mechanical properties and wear and corrosion resistance of electrodeposited Ni-Co/SiC nanocomposite coating

International Nuclear Information System (INIS)

Shi Lei; Sun Chufeng; Gao Ping; Zhou Feng; Liu Weimin

2006-01-01

Ni-Co/SiC nanocomposite coatings with various contents of SiC nano-particulates were prepared by electrodeposition in a Ni-Co plating bath containing SiC nano-particulates to be co-deposited. The influences of the nanoparticulates concentration, current density, stirring rate and temperature of the plating bath on the composition of the coatings were investigated. The shape and size of the SiC nano-particulates were observed and determined using a transmission electron microscope. The polarization behavior of the composite plating bath was examined on a PAR-273A potentiostat/galvanostat device. The wear behavior of the Ni-Co/SiC nanocomposite coatings was evaluated on a ball-on-disk UMT-2MT test rig. The worn surface morphologies of the Ni-Co/SiC nanocomposite coatings were observed using a scanning electron microscope. The corrosion behavior of the nanocomposite coatings was evaluated by charting the Tafel curves of the solution of 0.5 mol L -1 NaCl at room temperature. It was found that the cathodic polarization potential of the composite electrolyte increased with increasing SiC concentration in the plating bath. The microhardness and wear and corrosion resistance of the nanocomposite coatings also increased with increasing content of the nano-SiC in the plating bath, and the morphologies of the nanocomposite coatings varied with varying SiC concentration in the plating bath as well. Moreover, the co-deposited SiC nano-particulates were uniformly distributed in the Ni-Co matrix and contributed to greatly increase the microhardness and wear resistance of the Ni-Co alloy coating

Biomimetic nanocomposites of carboxymethyl cellulose-hydroxyapatite: novel three dimensional load bearing bone grafts.

Science.gov (United States)

Garai, Subhadra; Sinha, Arvind

2014-03-01

An innovative biomimetic synthesis of novel three dimensional micro/macro porous carboxymethyl cellulose (CMC)-hydroxyapatite (HA) nanocomposites having four systematically different compositions has been established for its possible application as a load bearing synthetic bone graft. Our process, being in situ, involves a simple and cost effective route akin to a matrix mediated biomineralization process. Developed synthesis route not only controls the size of HA particles in the range of 15-50 nm, embedded in CMC matrix, but also assists in the formation of a mechanically strong three dimensional nanocomposite structures due to physical cross linking of HA impregnated CMC matrix. The process does not involve any toxic cross linker and works at near ambient conditions. The nanocomposites are systematically structurally and mechanically characterized using various techniques like scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform IR (FTIR), solid state (13)C nuclear magnetic resonance ((13)C NMR), thermo-gravimetric analysis (TGA) and Universal mechanical test. It reveals that the ionic/polar or electrostatic interactions are the main driving force for formation of load bearing three dimensional nanocomposites via a process similar to matrix mediated biomineralization. Compressive strength and compressive modulus of nanocomposites, being in the range of 1.74-12 MPa and 157-330 MPa, respectively, meet the desired range of compressive strength for the synthetic grafts used in cancellous bone. An increase in the compressive strength with increase in the porosity has been an interesting observation in the present study. In vitro cytotoxicity of the synthesized nanocomposites has been evaluated using bone marrow mesenchymal stem cells (BMSC) isolated from Wistar rat. Copyright © 2013 Elsevier B.V. All rights reserved.

Fabrication and mechanical properties of multi-walled carbon nanotubes/epoxy nanocomposites

International Nuclear Information System (INIS)

Yeh, M.-K.; Hsieh, T.-H.; Tai, N.-H.

2008-01-01

Carbon nanotubes have better physical and mechanical behavior than the traditional materials. In this study, the multi-walled carbon nanotubes (MWNTs) were added to the epoxy resin as a reinforcement to fabricate MWNTs/epoxy nanocomposites. The pressure and temperature were applied to cure the MWNTs/epoxy compound by hot press method. Mechanical properties such as tensile strength, Young's modulus, and Poisson's ratio were measured. The effect of weight percentages of the MWNTs was investigated. Morphologies of the fracture surface of MWNTs/epoxy nanocomposites were observed by scanning electron microscope

Three-Dimensional Nanoporous Cellulose Gels as a Flexible Reinforcement Matrix for Polymer Nanocomposites.

Science.gov (United States)

Shi, Zhuqun; Huang, Junchao; Liu, Chuanjun; Ding, Beibei; Kuga, Shigenori; Cai, Jie; Zhang, Lina

2015-10-21

With the world's focus on utilization of sustainable natural resources, the conversion of wood and plant fibers into cellulose nanowhiskers/nanofibers is essential for application of cellulose in polymer nanocomposites. Here, we present a novel fabrication method of polymer nanocomposites by in-situ polymerization of monomers in three-dimensionally nanoporous cellulose gels (NCG) prepared from aqueous alkali hydroxide/urea solution. The NCG have interconnected nanofibrillar cellulose network structure, resulting in high mechanical strength and size stability. Polymerization of the monomer gave P(MMA/BMA)/NCG, P(MMA/BA)/NCG nanocomposites with a volume fraction of NCG ranging from 15% to 78%. SEM, TEM, and XRD analyses show that the NCG are finely distributed and preserved well in the nanocomposites after polymerization. DMA analysis demonstrates a significant improvement in tensile storage modulus E' above the glass transition temperature; for instance, at 95 °C, E' is increased by over 4 orders of magnitude from 0.03 MPa of the P(MMA/BMA) up to 350 MPa of nanocomposites containing 15% v/v NCG. This reinforcement effect can be explained by the percolation model. The nanocomposites also show remarkable improvement in solvent resistance (swelling ratio of 1.3-2.2 in chloroform, acetone, and toluene), thermal stability (do not melt or decompose up to 300 °C), and low coefficients of thermal expansion (in-plane CTE of 15 ppm·K(-1)). These nanocomposites will have great promising applications in flexible display, packing, biomedical implants, and many others.

Graphene oxide-silver nanocomposite as a promising biocidal agent against methicillin-resistant Staphylococcus aureus.

Science.gov (United States)

de Moraes, Ana Carolina Mazarin; Lima, Bruna Araujo; de Faria, Andreia Fonseca; Brocchi, Marcelo; Alves, Oswaldo Luiz

2015-01-01

Methicillin-resistant Staphylococcus aureus (MRSA) has been responsible for serious hospital infections worldwide. Nanomaterials are an alternative to conventional antibiotic compounds, because bacteria are unlikely to develop microbial resistance against nanomaterials. In the past decade, graphene oxide (GO) has emerged as a material that is often used to support and stabilize silver nanoparticles (AgNPs) for the preparation of novel antibacterial nanocomposites. In this work, we report the synthesis of the graphene-oxide silver nanocomposite (GO-Ag) and its antibacterial activity against relevant microorganisms in medicine. GO-Ag nanocomposite was synthesized through the reduction of silver ions (Ag(+)) by sodium citrate in an aqueous GO dispersion, and was extensively characterized using ultraviolet-visible absorption spectroscopy, X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, and transmission electron microscopy. The antibacterial activity was evaluated by microdilution assays and time-kill experiments. The morphology of bacterial cells treated with GO-Ag was investigated via transmission electron microscopy. AgNPs were well distributed throughout GO sheets, with an average size of 9.4±2.8 nm. The GO-Ag nanocomposite exhibited an excellent antibacterial activity against methicillin-resistant S. aureus, Acinetobacter baumannii, Enterococcus faecalis, and Escherichia coli. All (100%) MRSA cells were inactivated after 4 hours of exposure to GO-Ag sheets. In addition, no toxicity was found for either pristine GO or bare AgNPs within the tested concentration range. Transmission electronic microscopy images offered insights into how GO-Ag nanosheets interacted with bacterial cells. Our results indicate that the GO-Ag nanocomposite is a promising antibacterial agent against common nosocomial bacteria, particularly antibiotic-resistant MRSA. Morphological injuries on MRSA cells revealed a likely loss of viability as a result of the

Exfoliated graphite/titanium dioxide nanocomposites for photodegradation of eosin yellow

Energy Technology Data Exchange (ETDEWEB)

Ndlovu, Thabile, E-mail: atkuvarega@gmail.com [University of Swaziland, Department of Chemistry, Private Bag 4, Kwaluseni (Swaziland); Kuvarega, Alex T.; Arotiba, Omotayo A. [University of Johannesburg, Department of Applied Chemistry, P.O. Box 17011, Doornfontein 2028, Johannesburg (South Africa); Sampath, Srinivasan [Indian Institute of Science, Department of Inorganic and Physical Chemistry, Bangalore 560012 (India); Krause, Rui W. [Rhodes University, Department of Chemistry, P.O. Box 94, Grahamstown 6140 South Africa (South Africa); Mamba, Bhekie B., E-mail: bmamba@uj.ac.za [University of Johannesburg, Department of Applied Chemistry, P.O. Box 17011, Doornfontein 2028, Johannesburg (South Africa)

2014-05-01

Graphical abstract: - Highlights: • Preparation of exfoliated graphite (EG) from natural graphite. • Sol–gel anchoring of TiO{sub 2} on exfoliated graphite. • High adsorption and photoactivity was observed for the EG-TiO{sub 2} nanocomposite. • Mechanism of enhancement was proposed. - Abstract: An improved photocatalyst consisting of a nanocomposite of exfoliated graphite and titanium dioxide (EG-TiO{sub 2}) was prepared. SEM and TEM micrographs showed that the spherical TiO{sub 2} nanoparticles were evenly distributed on the surface of the EG sheets. A four times photocatalytic enhancement was observed for this floating nanocomposite compared to TiO{sub 2} and EG alone for the degradation of eosin yellow. For all the materials, the reactions followed first order kinetics where for EG-TiO{sub 2}, the rate constant was much higher than for EG and TiO{sub 2} under visible light irradiation. The enhanced photocatalytic activity of EG-TiO{sub 2} was ascribed to the capability of graphitic layers to accept and transport electrons from the excited TiO{sub 2}, promoting charge separation. This indicates that carbon, a cheap and abundant material, can be a good candidate as an electron attracting reservoir for photocatalytic organic pollutant degradation.

Photocatalytic Decolorization Study of Methyl Orange by TiO2–Chitosan Nanocomposites

Directory of Open Access Journals (Sweden)

Imelda Fajriati

2014-10-01

Full Text Available The photocatalytic decolorization of methyl orange (MO by TiO2-chitosan nanocomposite has been studied. This study was started by synthesizing TiO2-chitosan nanocomposites using sol-gel method with various concentrations of Titanium(IV isopropoxide (TTIP as the TiO2 precursor. The structure, surface morphology, thermal and optical property of TiO2-chitosan nanocomposite were characterized by X-ray diffraction (XRD, fourier transform infra red (FTIR spectroscopy, scanning electron microscopy (SEM, thermogravimetric analysis (TGA, and diffuse reflectance ultra violet (DRUV spectroscopy. The photocatalytic activity of TiO2-chitosan nanocomposite was evaluated by photocatalytic decolorization of methyl orange as a model pollutant. The results indicate that the particle size of TiO2 increases with increasing ofthe concentration of TTIP, in which TiO2 with smallest particle size exhibit the highest photocatalytic activity. The highest photocatalytic decolorization was obtained at 5 h of contact time, initial concentration of MO at 20 ppm and at solution pH of 4. Using these conditions, over 90% of MO was able to be decolorized using 0.02 g of TiO2-chitosan nanocomposite under UV light irradiation. The TiO2-chitosan nanocomposite could be reused, which meant that the TiO2-chitosan nanocomposites can be developed as an effective and economical photocatalyst to decolorize or treat dye in wastewater.

A novel intumescent flame retardant-functionalized graphene: Nanocomposite synthesis, characterization, and flammability properties

International Nuclear Information System (INIS)

Huang, Guobo; Chen, Suqing; Tang, Shouwan; Gao, Jianrong

2012-01-01

An intumescent flame retardant, poly(piperazine spirocyclic pentaerythritol bisphosphonate) (PPSPB), has been covalently grafted onto the surfaces of graphene oxide (GO) to obtain GO–PPSPB and according nanocomposites were prepared via solvent blending. The X-ray diffraction (XRD) and transmission electron microscopy (TEM) results show that the chemically reduced GO–PPSPB (CRG–PPSPB) can achieve better dispersion in the ethylene vinyl acetate copolymer (EVA) matrix and exfoliated EVA/CRG–PPSPB nanocomposites are formed. The results from thermogravimetric analysis (TGA) and cone calorimeter tests indicate that CRG–PPSPB improve thermal stability and reduce obviously the flammability (including peak heat release rate (PHRR), total heat release (THR), average mass loss rate (AMLR), etc.) of EVA. Compared with pure EVA resin, the PHRR of the EVA/CRG–PPSPB nanocomposites filled with 1 wt% CRG–PPSPB is reduced by about 56%. The SEM images show that a compact, dense and uniform intumescent char is formed for EVA/CRG–PPSPB nanocomposites after combustion. The functionalization of graphene by intumescent flame retardant PPSPB can improve both the dispersion of graphene sheets in the polymer matrix and flame retardancy of the nanocomposites. -- Highlights: ► Graphene oxide were modified with intumescent flame retardant PPSPB. ► EVA/CRG–PPSPB nanocomposites were prepared via solvent blending. ► CRG–PPSPB improved the flame retardancy of EVA nanocomposites.

Analysis of Gas Permeability Characteristics of Poly(Lactic Acid/Poly(Butylene Succinate Nanocomposites

Directory of Open Access Journals (Sweden)

Amita Bhatia

2012-01-01

Full Text Available Gas permeability and morphological properties of nanocomposites prepared by the mixing of poly(lactic acid (PLA, poly(butylene succinate (PBS, and clay was investigated. While the composition of PLA and PBS polymers was fixed as 80% and 20% by weight, respectively, for all the nanocomposites, clay contents varied from 1 to 10 wt%. From the morphological studies using both wide angle X-ray diffraction and transmission electron microscopy, the nanocomposite having 1 wt% of clay was considered to have a mixed morphology of intercalated and delaminated structure, while some clusters or agglomerated particles were detected for nanocomposites having 3 and more than 3 wt% of clay content. However, the average particle size of the dispersed PBS phase was reduced significantly from 7 μm to 30–40 nm with the addition of clay in the blend. The oxygen barrier property was improved significantly as compared to the water vapor. A model based on gas barrier property was used for the validation of the oxygen relative permeabilities of PLA/PBS/clay nanocomposites. PLA/PBS/clay nanocomposites validated the Bharadwaj model up to 3 wt% of clay contents only, while for nanocomposites of higher clay contents the Bharadwaj model was invalid due to the clusters and agglomerates formed.

Preparation, characterization and photocatalytic activity of visible-light-driven plasmonic Ag/AgBr/ZnFe2O4 nanocomposites

International Nuclear Information System (INIS)

Li, Xiaojuan; Tang, Duanlian; Tang, Fan; Zhu, Yunyan; He, Changfa; Liu, Minghua; Lin, Chunxiang; Liu, Yifan

2014-01-01

Highlights: • A plasmonic Ag/AgBr/ZnFe 2 O 4 photocatalyst has been successfully synthesized. • Ag/AgBr/ZnFe 2 O 4 nanocomposites exhibit high visible light photocatalytic activity. • Ag/AgBr/ZnFe 2 O 4 photocatalyst is stable and magnetically separable. - Abstract: A visible-light-driven plasmonic Ag/AgBr/ZnFe 2 O 4 nanocomposite has been successfully synthesized via a deposition–precipitation and photoreduction through a novel one-pot process. X-ray diffraction spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and UV–vis diffuse reflectance spectroscopy were employed to investigate the crystal structure, chemical composition, morphology, and optical properties of the as-prepared nanocomposites. The photocatalytic activities of the nanocomposites were evaluated by photodegradation of Rhodamine B (RhB) and phenol under visible light. The results demonstrated that the obtained Ag/AgBr/ZnFe 2 O 4 nanocomposites exhibited higher photocatalytic activity as compared to pure ZnFe 2 O 4 . In addition, the sample photoreduced for 20 min and calcined at 500 °C achieved the highest photocatalytic activity. Furthermore, the Ag/AgBr/ZnFe 2 O 4 nanocomposite has high stability under visible light irradiation and could be conveniently separated by using an external magnetic field

A comparison study of polymer/cobalt ferrite nano-composites synthesized by mechanical alloying route