Showing papers on "Nanocomposite published in 2000"
TL;DR: In this article, a review of polymer-layered silicate nanocomposites is presented, where the polymer chains are sandwiched in between silicate layers and exfoliated layers are more or less uniformly dispersed in the polymer matrix.
Abstract: This review aims at reporting on very recent developments in syntheses, properties and (future) applications of polymer-layered silicate nanocomposites. This new type of materials, based on smectite clays usually rendered hydrophobic through ionic exchange of the sodium interlayer cation with an onium cation, may be prepared via various synthetic routes comprising exfoliation adsorption, in situ intercalative polymerization and melt intercalation. The whole range of polymer matrices is covered, i.e. thermoplastics, thermosets and elastomers. Two types of structure may be obtained, namely intercalated nanocomposites where the polymer chains are sandwiched in between silicate layers and exfoliated nanocomposites where the separated, individual silicate layers are more or less uniformly dispersed in the polymer matrix. This new family of materials exhibits enhanced properties at very low filler level, usually inferior to 5 wt.%, such as increased Young’s modulus and storage modulus, increase in thermal stability and gas barrier properties and good flame retardancy.
5,901 citations
TL;DR: In this article, a review of inorganic nanoparticles with conducting polymers, giving rise to a host of nanocomposites with interesting physical properties and important application potential are discussed.
Abstract: Inorganic nanoparticles of different nature and size can be combined with the conducting polymers, giving rise to a host of nanocomposites with interesting physical properties and important application potential. Such nanocomposites have been discussed in this review, throwing light on their synthesis techniques, properties, and applications. A large variety of nanoparticles have been chosen in this respect with inclusion techniques utilizing both chemical and electrochemical routes. The nature of the association between the components can be studied from TEM pictures. Depending upon the synthesis techniques and the characteristics of the inorganic materials, ultimate properties of the resulting composite are controlled. In this way, the exceptional colloidal stability of different silica sols have been utilized to form stable PPy-silica and PAn-silica nanocomposite colloids. Similarly the magnetic susceptibility of γ-Fe2O3, the elctrochromic property of WO3, and the catalytic activity of Pd, Pt, etc. met...
1,244 citations
Book•
01 Jan 2000
Abstract: Contributors. Series Preface. Preface. Polymer-clay Intercalates. Layered Silicate-Polymer Intercalation Compounds. Electroactive Polymers Intercalated in Clays and Related Solids. Polymer-Clay Nanocomposites Derived from Polymer-Silicate Gels. Polymerization of Organic Monomers and Biomolecules on Hectorite. Nanocomposite Synthesis and Properties. Polymer-Clay Nanocomposites. In Situ Polymerization Route to Nylon 6-Clay Nanocomposites. Epoxy-Clay Nanocomposites. Polypropylene-Clay Nanocomposites. Polyethylene Terephthalate-Clay Nanocomposites. Special Properties and Applications. Polymer-Layered Silicate Nanocomposites with Conventional Flame Retardants. Nanocomposite Technology for Enhancing the Gas Barrier of Polyethylene Terephthalate. Structure and Rheology. Structural Characterization of Polymer-Layered Silicate Nanocomposites. New Conceptual Model for Interpreting Nanocomposite Behavior. Modeling the Phase Behavior of Polymer-Clay Nanocomposites. Rheological Properties of Polymer-Layered Silicate Nanocomposites. Index.
1,167 citations
Book•
01 Jan 2000
TL;DR: Theoretical Aspects of Strained-layer Quantum-Well Lasers are discussed in this article, as well as their application in the synthesis and characterization of nanostructured materials.
Abstract: Volume 1: Synthesis and Processing HG Jiang, ML Lau, VL Telkamp, and EJ Lavernia, Synthesis of Nanostructured Coatings by High Velocity Oxygen Fuel Thermal Spraying KE Gonsalves, SP Rangarajan, and J Wang, Chemical Synthesis of Nanostructured Metals, Metal Alloys, and Semiconductors J Costa, Nanoparticles from Low-Pressure and Low-Temperature Plasma CD Johnson, M Noh, H Sellinschegg, R Schneidmiller, and DC Johnson, Kinetic Control of Inorganic Solid State Reactions Resulting from Mechanistic Studies Using Elementally Modulated Reactants EJ Gonzalez and GJ Piermarini, Low Temperature Compaction on Nanosize Powders WH Weinberg, CM Reaves, BZ Nosho, RI Pelzel, and SP denBaars, Strained-layer Heteroepitaxy to Fabricate Self-assembled Semiconductor Islands JJ McClelland, Nanofabrication via Atom Optics KC Kwaitkowski and CM Lukehart, Nanocomposites Prepared by Sol-Gel Methods: Synthesis and Characterization Q Yitai, Chemical Preparation and Characterization of Nanocrystalline Materials DJ Duval and SH Risbud, Semiconductors Quantum Dots-Progress in Processing ITH Chang, Rapid Solidification Processing of Nanocrystalline Metallic Alloys KL Choy, Vapor Processing of Nanostructured Materials Volume 2: Spectroscopy and Theory JM Cowley and JCH Spence, Nanodiffraction M-I Baraton, FT-IR Surface Spectrometry of Nanosized Particles P Milani and CE Bottani, Vibrational Spectroscopy of Mesoscopic Systems RM Taylor II and R Superfine, Advanced Interfaces to Scanning-probe Microscopes R Blick, Microwave Spectroscopy on Quantum Dots E Meyer and R Luthi, Tribological Experiments with Friction Force Microscopy M J Yacaman and JA Ascencia, Electron Microscopy Techniques Applied to Study of Nanostructured Materials and Ancient Materials K Ounadjela and RL Stamps, Mesoscopic Magnetism in Metals DJ Whitehouse, Tools of Nanotechnology: Nanometrology VGasparian, M Ortuno, G Schon, and U Simon, Tunneling Times in Nanostructures SB Sinnott, Theory of Atomic-Scale Friction D Ahn, Theoretical Aspects of Strained-layer Quantum-Well Lasers LR Ram Mohan, I Vurgaftman, and JR Meyer, Wavefunction Engineering: A New Paradigm in Quantum Nanostructure Modeling Volume 3: Electrical Properties J Smolines and G Ploner, Electron Transport and Confining Potentials in Semiconductor Nanostructures MA Reed, JW Sleight, and MR Deshpande, Electron Transport Properties of Quantum Dots U Simon and G Schon, Electrical Properties of Chemically Tailored Nanoparticles and Their Applications in Microelectronics RP Andres, S Datta, DB Janes, CP Kubiak, and R Reifenberger, Design, Fabrication, and Electronic Properties of Self-assembled Molecular Nanostructures TP Sidiki and CM Sotomayor Torres, Silicon-based Nanostructures PV Kamat, K Murakoshi, Y Wada, and S Yanagida, Semiconductor Nanoparticles FM Peeters and J DeBoeck, Hybrid Magnetic-Semiconductor Nanostructures OI Micic and AJ Nozik, Colloidal Quantum Dots of III-V Semiconductors VV Moshchalkov, Y Bruynseraede, L Van Look, MJ Van Bael, Y Bruynseraede, and A Tonomura, Quantization and Confinement Phenomena in Nanostructured Superconductors M Graetzel, Properties and Applications of Nanocrystalline Electronic Junctions S Mitsui, Nanostructured Fabrication Using Electron Beam and Its Applications to Nanometer Devices Volume 4: Optical Properties DD Notle, MR Melloch, Y Ding, M Dinu, KM Kwolek, and I Lahiri, Photorefractive Semiconductor Nanostructures F Gonella and P Mazzoldi, Metal Nanocluster Composite Glasses D Thomas, Porous Silicon W Chen, Fluorescence, Thermoluminescence, and Photostimulated Luminescence of Nanoparticles VM Shalaev, Surface-enhanced Optical Phenomena in Nanostructured Fractal Materials VI Klimov, Linear and Nonlinear Optical Spectroscopy of Semiconductor Nanocrystals S Vijayalakshmi and H Grebel, Nonlinear Optical Properties of Nanostructures SS Li and MZ Tidrow, Quantum Well Infrared Photodetectors W Tan and R Kopelman, Nanoscopic Optical Sensors and Probes Volume 5: Organics, Polymers, and Biological Materials PJ Stang and B Olenyuk, Transition-Metal-Mediated Self-Assembly of Discrete Nanoscopic Species with Well-Defined Shapes and Geometries M Gomez-Lopez and JF Stoddart, Molecular and Supramolecular Nanomachines AC Benniston and PR Mackie, Functional Nanostructures Incorporating Responsive Modules A Archut and F Voegtle, Dendritic Molecules: Historical Developments and Future Applications PM Ajayan, Carbon Nanotubes J Sloan and MLH Green, Encapsulation and Crystallization Behavior of Materials Inside Carbon Nanotubes H Kasai, HS Nalwa, S Okada, H Oikawa, and H Nakanishi, Fabrication and Spectroscopic Characterization of Organic Nanocrystals G Liu, Polymeric Nanostructures B Wessling, Conducting Polymers as Organic Nanometals E Nakache, N Poulain, F Candau, AM Orecchioni, and JM Irache, Biopolymers and Polymers Nanoparticles and Their Biomedical Applications T Bayburt, J Carlson, B Godfrey, M Shank-Retzlaff, and SG Sligar, Structure, Behavior, and Manipulation of Nanostructure Biological Assemblies TM Cooper, Biomimetic Thin Films
964 citations
TL;DR: In this article, the development of hard coatings from a titanium nitride film through superlattice coatings to nanocomposite coatings is reviewed, and significant attention is devoted to hard and superhard single layer nano-coating.
Abstract: This article reviews the development of hard coatings from a titanium nitride film through superlattice coatings to nanocomposite coatings. Significant attention is devoted to hard and superhard single layer nanocomposite coatings. A strong correlation between the hardness and structure of nanocomposite coatings is discussed in detail. Trends in development of hard nanocomposite coatings are also outlined.
955 citations
TL;DR: In this paper, a composite structure study revealed a coexistence of exfoliated and intercalated MMT layers, especially for low and moderate silicate loadings, which promoted a new crystalline phase different than the one of the respective neat PVA, characterized by higher melting temperature and a different crystal structure.
Abstract: Poly(vinyl alcohol)/sodium montmorillonite nanocomposites of various compositions were created by casting from a polymer/silicate water suspension. The composite structure study revealed a coexistence of exfoliated and intercalated MMT layers, especially for low and moderate silicate loadings. The inorganic layers promote a new crystalline phase different than the one of the respective neat PVA, characterized by higher melting temperature and a different crystal structure. This new crystal phase reflects on the composite materials properties. Namely, the hybrid polymer/silicate systems have mechanical, thermal, and water vapor transmission properties, which are superior to that of the neat polymer and its conventionally filled composites. For example, for a 5 wt % MMT exfoliated composite, the softening temperature increases by 25 °C and the Young's modulus triples with a decrease of only 20% in toughness, whereas there is also a 60% reduction in the water permeability. Furthermore, due to the nanoscale d...
764 citations
TL;DR: The template-based synthesis of carbon nanotubes has been demonstrated as this is the most promising class of new carbon-based materials for electronic and optic nanodevices as well as reinforcement nanocomposites.
Abstract: The large interest in nanostructures results from their numerous potential applications in various areas such as materials and biomedical sciences, electronics, optics, magnetism, energy storage, and electrochemistry. Ultrasmall building blocks have been found to exhibit a broad range of enhanced mechanical, optical, magnetic, and electronic properties compared to coarser-grained matter of the same chemical composition. In this paper various template techniques suitable for nanotechnology applications with emphasis on characterization of created arrays of tailored nanomaterials have been reviewed. These methods involve the fabrication of the desired material within the pores or channels of a nanoporous template. Track-etch membranes, porous alumina, and other nanoporous structures have been characterized as templates. They have been used to prepare nanometer-sized fibrils, rods, and tubules of conductive polymers, metals, semiconductors, carbons, and other solid matter. Electrochemical and electroless depositions, chemical polymerization, sol-gel deposition, and chemical vapour deposition have been presented as major template synthetic strategies. In particular, the template-based synthesis of carbon nanotubes has been demonstrated as this is the most promising class of new carbon-based materials for electronic and optic nanodevices as well as reinforcement nanocomposites.
615 citations
TL;DR: In this paper, the melt-state linear viscoelastic properties for a series of intercalated nanocomposites are examined and the linear dynamic oscillatory moduli and the stress relaxation moduli are in quantitative agreement and suggest that at short times the relaxation of the nanocom composites is essentially unaffected by the presence of layered-silicate.
Abstract: The melt-state linear viscoelastic properties for a series of intercalated nanocomposites are examined. The nanocomposites are based on a short disordered polystyrene−polyisoprene diblock copolymer and varying amounts of dimethyldioctadecylammonium modified montmorillonite. The linear dynamic oscillatory moduli and the stress relaxation moduli are in quantitative agreement and suggest that at short times the relaxation of the nanocomposites is essentially unaffected by the presence of the layered-silicate. However, at long times (or equivalently low frequency), the hybrids exhibit dramatically altered viscoelastic behavior. Hybrids with silicate loadings in excess of 6.7 wt % exhibit pseudo-solidlike behavior, similar to that observed in previous studies of exfoliated end-tethered nanocomposites. On the basis of simple phenomenological arguments, the long time behavior is attributed to the presence of anisotropic stacks of silicate sheets randomly oriented and forming a percolated network structure that i...
566 citations
TL;DR: In this article, the authors review the advances in the development of plasma processes and plasmasystems for the synthesis of thin film high and low index optical materials, and in the control of plasma surface interactions leading to desired film microstructures.
Abstract: Plasma enhanced chemical vapor deposition(PECVD) is being increasingly used for the fabrication of transparent dielectric optical films and coatings. This involves single-layer, multilayer, graded index, and nanocomposite optical thin filmsystems for applications such as optical filters, antireflective coatings, optical waveguides, and others. Beside their basic optical properties (refractive index, extinction coefficient, optical loss), these systems very frequently offer other desirable “functional” characteristics. These include hardness, scratch, abrasion, and erosion resistance, improved adhesion to various technologically important substrate materials such as polymers, hydrophobicity or hydrophilicity, long-term chemical, thermal, and environmental stability, gas and vapor impermeability, and others. In the present article, we critically review the advances in the development of plasma processes and plasmasystems for the synthesis of thin film high and low index optical materials, and in the control of plasma–surface interactions leading to desired film microstructures. We particularly underline those specificities of PECVD, which distinguish it from other conventional techniques for producing optical films (mainly physical vapor deposition), such as fabrication of graded index (inhomogeneous) layers, control of interfaces, high deposition rate at low temperature, enhanced mechanical and other functional characteristics, and industrial scaleup. Advances in this field are illustrated by selected examples of PECVD of antireflective coatings, rugate filters, integrated optical devices, and others.
542 citations
TL;DR: In this paper, the percolation of the carbon nanotubes was studied and discussed in relation to the nature of the matrix, the electrical conductivity, the fracture strength and the fracture toughness.
530 citations
TL;DR: In this paper, a survey on nano-particles and nanocomposites and the importance of small particle sizes on their optical properties is presented, focusing on results from a laboratory concerning nanocom composites with extremely high or low refractive indices and dichroic nanocomposition and their application in bicolored liquid crystal displays.
Abstract: Upon transmission of visible light through composites comprising of a transparent polymer matrix with embedded particles, the intensity loss by scattering is substantially reduced for particle diameters below 50-100 nm (nanoparticles, nanosized particles). As a consequence, related materials (nanocomposites) have found particular interest in optical studies. The first part of this article deals with a historical survey on nano-particles and nanocomposites and the importance of small particle sizes on their optical properties. The second part focuses on results from our laboratory concerning nanocomposites with extremely high or low refractive indices and dichroic nanocomposites and their application in bicolored liquid crystal displays (LCD). The inorganic colloids required for these studies (lead sulfide, iron sulfides, gold, and silver) were prepared in situ in presence of a polymer or isolated as redispersable metal colloids modified at the surface with a self-assembled monolayer (SAM) of an alkanethiol. The nanocomposites themselves were finally obtained by coprecipitation, spin coating, solvent casting or melt extrusion, with poly(ethylene oxide), gelatin, poly(vinyl alcohol) and polyethylene as matrix polymers.
TL;DR: A more general technique involves compatibilization of the silicate by intercalation of an organic molecule, typically an organic alkylammonium salt, that replaces the cations in the interlayer galleries to form an organically modified layered silicate (OLS) as discussed by the authors.
Abstract: Polymers filled with low amounts of layered silicate dispersed at nanoscale level are most promising materials characterized by a combination of chemical, physical and mechanical properties that cannot be obtained with macro- or microscopic dispersions of inorganic fillers. Polymer layered silicate nanocomposites can be obtained by insertion of polymer molecules in the galleries between the layers of phyllosilicate. Here, hydrated alkaline or alkaline earth metal cations are hosted which neutralize the negative charge resulting from isomorphous substitutions of Mg or Al cations within the silicate. Insertion of polymer molecules to prepare “intercalation hybrids” can be carried out by replacing the water hydration molecules in the galleries by polymers containing polar functional groups, using the so called ion-dipole method. A more general technique involves compatibilization of the silicate by intercalation of an organic molecule, typically an organic alkylammonium salt, that replaces the cations in the interlayer galleries to form an organically modified layered silicate (OLS). The aliphatic chain of the OLS favors the intercalation of any type of polymer. Intercalated or delaminated polymer-silicate hybrids are obtained depending on whether the stack organization of the silicate layers is preserved or is lost, with single sheets being distributed in the polymer matrix. The methods currently used for preparing polymer layered silicate (PLS) nanocomposites are: in situ polymerization, from polymer solution, or from polymer melt. Although PLS nanocomposites have been known for a long time, it is the possibility of preparing them by melt intercalation of OLS in processing that is boosting the present interest in these materials and their properties. So far PLS nanocomposites have been characterized by X-ray diffractometry, transmission electron microscopy, differential scanning calorimetry, and NMR. Published results on PLS nanocomposites are reviewed concerning their characterization and properties with particular reference to fire retardant behavior.
TL;DR: In this article, the use of nanometre thick silica shells as a means to stabilize metal clusters and semiconductor particles is discussed, and its potential advantages over conventional organic capping agents are presented.
Abstract: The use of nanometre thick silica shells as a means to stabilize metal clusters and semiconductor particles is discussed, and its potential advantages over conventional organic capping agents are presented. Shell deposition depends on control of the double layer potential, and requires priming of the core particle surface. Chemical reactions are possible within the core, via diffusion of reactants through the shell layer. Quantum dots can be stabilized against photochemical degradation through silica deposition, whilst retaining strong fluorescence quantum yields and their size dependent optical properties. Ordered 3D and 2D arrays of a macroscopic size with uniform particle spacing can be created. Thin colloid films can also be created with well-defined interparticle spacing, allowing controlled coupling of exciton and surface plasmon modes to be investigated. A number of future core–shell nanocomposite structures are postulated, including quantum bubbles and single electron capacitors based on Au@SiO2.
TL;DR: In this article, the authors present a Web of Science Record created on 2006-02-21, modified on 2017-05-12.Reference LPI-ARTICLE-2000-029
Abstract: Reference LPI-ARTICLE-2000-029View record in Web of Science Record created on 2006-02-21, modified on 2017-05-12
TL;DR: In this article, an original catalytic method that produces ceramic-matrix composite powders that contain in situ grown nanotubes is described, and the synthesis parameters that favour the obtention of very high quantities of carbon-nanotubes are discussed.
TL;DR: In this article, a detailed impedance spectroscopy study was carried out on poly(ethylene oxide) [P(EO)]-based polymer electrolyte samples with and without ceramic fillers.
Abstract: The addition of nanometric fillers (e.g., , ) to polymer electrolytes induces consistent improvement in the transport properties. The increase in conductivity and in the cation transference number is attributed to the enhancement of the degree of the amorphous phase in the polymer matrix, as well as to some acid‐base Lewis type, ceramic‐electrolyte interactions. This model is confirmed by results obtained from a detailed impedance spectroscopy study carried out on poly(ethylene oxide) [P(EO)]‐based polymer electrolyte samples with and without ceramic fillers. © 2000 The Electrochemical Society. All rights reserved.
TL;DR: In this paper, a general technique for the hydrothermal synthesis of clay minerals in the presence of organic, organometallic, and polymeric intercalants is described, along with their characterization and materials applications.
TL;DR: In this paper, a new process was developed to fabricate electrically conducting nylon 6/graphite nanocomposites via intercalation polymerization of ϵ-caprolactam in the presence of expanded graphite.
Abstract: A new process was developed to fabricate electrically conducting nylon 6/graphite nanocomposites via intercalation polymerization of ϵ-caprolactam in the presence of expanded graphite. The transition from an electrical insulator to an electrical semiconductor for nylon 6 occurred when the graphite volume content was 0.75, which was much lower than that of conventional conducting polymer composites. The electrical conductivity reached 10−4 S/cm when the graphite content was 2.0 vol %. The TEM microphotographs suggested that the low percolation threshold and the great improvement of electrical conductivity could be attributed to the high aspect ratio (width-to-thickness), the high expansion ratio in c axis of the graphite sheets and the homogeneous dispersion of the nanoscale graphite particles in the nylon 6 matrix. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1626–1633, 2000
TL;DR: In this article, a flame retardant (FR) intumescent formulations for ethylene-vinyl acetate copolymers (EVA) using charring polymers polyamide-6 (PA-6) and polyamide6 clay nanocomposite hybrid was used as carbonization agents.
Abstract: This work deals with new flame retardant (FR) intumescent formulations for ethylene-vinyl acetate copolymers (EVA) using charring polymers polyamide-6 (PA-6) and polyamide-6 clay nanocomposite hybrid (PA-6-nano) as carbonization agents. Use of PA-6 nano improved both the mechanical and fire properties of FR EVA-based materials. The part played by the clay in the improvement of the FR performance was studied using FTIR and solid state NMR. It is shown that the clay allowed the thermal stabilization of a phosphorocarbonaceous structure in the intumescent char which increased the efficiency of the shield and, in addition, the formation of a ‘ceramic’ which can act as a protective barrier. Copyright © 2000 John Wiley & Sons, Ltd.
TL;DR: In this article, a model describing the evolution of microstructure has been developed for WC-Co coatings in high velocity oxy-fuel thermal spraying of conventional and nanocomposite powders which contain WC grains in the size range 2-5μm and 70-250nm, respectively.
TL;DR: In this article, the conductivity of reprotonated PANI/TiO2 composite film cast from its suspension in m-cresol and chloroform is higher than that of the film cast using its chloro-form suspension due to well-extended conjugation chain of PANI.
TL;DR: In recent years significant progress has been achieved in the synthesis of various types of polymer-nanocomposites and in the understanding of the basic principles which determine their optical, electronic and magnetic properties.
Abstract: In recent years significant progress has been achieved in the synthesis of various types of polymer-nanocomposites and in the understanding of the basic principles which determine their optical, electronic and magnetic properties. As a result nanocomposite-based devices, such as light emitting diodes, photodiodes, photovoltaic solar cells and gas sensors, have been developed, often using chemically orientated synthetic methods such as soft lithography, lamination, spin-coating or solution casting.
TL;DR: The role of various quaternary ammonium-modified montmorillonites in epoxy/diamine nanocomposite formation is examined to further refine the criteria for selection of organic modifiers necessary to enable fabrication of thermoset resins containing nanoscale dispersions of inorganic phases as mentioned in this paper.
Abstract: The role of various quaternary ammonium-modified montmorillonites in epoxy/diamine nanocomposite formation is examined to further refine the criteria for selection of organic modifiers necessary to enable fabrication of thermoset resins containing nanoscale dispersions of inorganic phases. Utilization of a hydroxyl-substituted quaternary ammonium modifier affords flexibility to combine both catalytic functionality, which increases the intragallery reaction rate, with enhanced miscibility toward both reagents. The rheological implications of these processing techniques are discussed with regards to using thermoset nanocomposites as a matrix in conventional fiber reinforced composites. The use of a low-boiling solvent to enhance mixability and processability of the initial mixtures is shown not to alter the structure or properties of the final nanocomposite. Also, the use of autoclave techniques enabled fabrication of high-quality specimens containing up to 20 wt % organically modified layered silicate (OLS...
TL;DR: In this paper, homopolymerization of 4-vinylpyridine (4VP) in the presence of an ultrafine silica sol using a free-radical initiator in aqueous media at 60 °C was used to synthesize polymer−silica nanocomposite particles.
Abstract: Colloidal dispersions of polymer−silica nanocomposite particles were synthesized in high yield by homopolymerizing 4-vinylpyridine (4VP) in the presence of an ultrafine silica sol using a free-radical initiator in aqueous media at 60 °C. Copolymerization of 4VP with methyl methacrylate and styrene also produced colloidally stable nanocomposite particles, in some cases for comonomer feeds containing as little as 6 mol % 4VP. However, homopolymerization of styrene or methyl methacrylate in the presence of the silica sol did not produce nanocomposite particles in control experiments. Thus a strong acid−base interaction between the silica sol and the (co)polymer appears to be essential for nanocomposite formation. Transmission electron microscopy studies confirmed the presence of the ultrafine silica sols within the nanocomposite particles, which typically exhibited “currant-bun” particle morphologies. This is in contrast to the “raspberry” particle morphologies previously reported for conducting polymer−sili...
TL;DR: In this article, a polyvinyl acetate intercalated graphite oxide nanocomposite was prepared by an in situ intercalative polymerization reaction, in which an n-octanol-graphite oxide intercalation compound was first obtained, and then the vinyl acetate monomer was then dispersed into the interlayer of the modified graphite oxide, followed by thermally polymerizing the monomer.
Abstract: Graphite oxide, a pseudo-two-dimensional solid in bulk form, was synthesized from natural graphite powder by graphite oxidation with KMnO4 in concentrated H2SO4. Poly(vinyl acetate) intercalated graphite oxide nanocomposite was prepared by an in situ intercalative polymerization reaction, in which an n-octanol–graphite oxide intercalation compound was first obtained, vinyl acetate monomer was then dispersed into the interlayer of the modified graphite oxide, followed by thermally polymerizing the monomer. It was experimentally shown that the c-axis spacing increased to 1.152 nm when poly(vinyl acetate) was intercalated into the interlayer space of the graphite oxide. Thermal analysis and FT-IR spectrometry were also used to characterize the nanocomposite. The extractability of the intercalated poly(vinyl acetate) and the electrical properties of the nanocomposite were evaluated.
TL;DR: The mechanism for the fire retardancy of these composites is generally considered to be due to the structure of the char formed during combustion, which enables the char to thermally insulate the polymer and inhibit the formation and escape of volatiles during combustion as discussed by the authors.
Abstract: Most fire retardant nanocomposites are made from layered silicates and organic polymers, a variety of methods are used in their synthesis. The mechanism for the fire retardancy of these composites is generally considered to be due to the structure of the char formed during combustion, which enables the char to thermally insulate the polymer and inhibit the formation and escape of volatiles during combustion. Fire retardant nanocomposites require relatively low concentrations of silicates for activity, resulting in low additional costs and weight. Improvements in the bulk physical properties of the polymer can be additional advantages over traditional fire retardants.
TL;DR: Rubber-clay nanocomposites were prepared by two different methods and characterized with TEM and XRD as discussed by the authors, which showed that the clay layer could be uniformly dispersed in the rubber matrix on the nanometer level.
Abstract: Rubber–clay nanocomposites were prepared by two different methods and characterized with TEM and XRD. The TEM showed clay had been dispersed to one or several layers. The XRD showed that the basal spacing in the clay was increased. It was evident that some macromolecules intercalated to the clay layer galleries. The clay layer could be uniformly dispersed in the rubber matrix on the nanometer level. The mechanical tests showed that the nanocomposites had good mechanical properties. Some properties exceeded those of rubber reinforced with carbon black, so the clay layers could be used as an important reinforcing agent as the carbon black was. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1879–1883, 2000
TL;DR: In this paper, the authors demonstrate that a successful approach for overcoming these problems is the dispersion of selected, low-particle size ceramic powders in the polymer mass with the aim of developing new types of nanocomposite PEO-LiX polymer electrolytes characterized by enhanced interfacial stability as well as by improved ambient temperature transport properties.
TL;DR: In this article, the effect of nanoparticles on the two component Ormosil type of hybrids composed of ethyl ortho-silicate (TEOS) and methylethoxy(methoxy)triethoxy silane (MTEOS, MTMOS) is discussed.
Abstract: Nanoparticles containing hybrid materials became of interest for many areas in the last decade. The reason for this is the fact that, in addition to the molecular inorganic-organic hybrid network, the physical, electronical, optical or catalytical properties of nanoparticles resulting from the inorganic crystalline, glassy or metallic properties also can be used for the material tailoring. For this reason, a survey is given over some interesting developments. Furthermore, in case studies, examples are given for the effect of nanoparticles on the two component Ormosil type of hybrids composed of ethyl ortho-silicate (TEOS) and methylethoxy(methoxy)triethoxy silane (MTEOS, MTMOS). It was shown that the 6 nm SiO2-containing nanocomposite hybrid sols can be dried in form of thick films up to 14 μm after a one step dip-coating process and densified crack-free. This is attributed to the increase of relaxation ability and flexibility. This nanocomposite based on TEOS, MTEOS and particulate SiO2 has been used to develop an industrial process for a new type of environmentally friendly glass fiber mat with a temperature resistance up to 600°C.
30 Jun 2000-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, a 20vol.%Al2O3 nanocomposite material has been successfully produced by using a new approach, which involves mechanical alloying of Cu and Al powders to produce Cu-Al alloy powder, mechanical milling of the Cu−Al powder together with CuO powder, and consolidation of the composite powder produced by milling.
Abstract: A Cu-20vol.%Al2O3 nanocomposite material has been successfully produced by using a new approach. This approach involves mechanical alloying of Cu and Al powders to produce Cu–Al alloy powder, mechanical milling of the Cu–Al powder together with CuO powder, and consolidation of the composite powder produced by milling. It has been observed that mechanical alloying of Cu and Al powders with Cu/Al atomic ratio of six leads to formation of a Cu(Al) solid solution. When the Cu(Al) solid solution powder is milled with CuO powder, reaction between Cu(Al) and CuO occurs, extracting Al solute from the Cu(Al) solution and turning it back to pure Cu. It has been identified that the Al2O3 particles in the consolidated composite material have a size smaller than 200 nm in diameter.