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Nanocomposite Systems (nanocomposite + system)
Selected AbstractsNanocomposite systems based on unsaturated polyester and organo-clayPOLYMER ENGINEERING & SCIENCE, Issue 2 2005I. Mironi-Harpaz Unsaturated polyester (UP) systems give rise to numerous possible approaches in synthesizing nanocomposites. A simultaneous mixing method was used to synthesize UP-resin/organo-clay nanocomposites. The effects of various mixing processes, using several organically-modified clay types, were investigated. The incorporation of these organo-clays resulted in an intercalated structure, the extent of which depended mainly on the type of the clay organic treatment. Organo-clays that exhibited the highest intercalation levels were further studied using a sequential mixing method. The UP-alkyd (without styrene) was mixed with different organo-clays. Processing parameters such as mixing modes, applied shearing levels, clay contents, and mixing-temperatures were investigated. Prolonged high shear levels promoted the intercalation and exfoliation of the silicate layers, resulting in a better dispersion of clay particles. The high shear levels effects were achieved by vigorous mechanical mixing and were intensified by using large amounts of clay and optimized matrix viscosity. Rheological studies of the nanocomposites were found complementary and in correlation with morphological and thermal characterization. This methodological approach provides a basis for understanding the structuring processes involving the formation of the UP/clay nanocomposites and establishing materials-processing-structure interrelations. Polym. Eng. Sci. 45:174,186, 2005. © 2005 Society of Plastics Engineers. [source] Ferromagnetic nanoparticles embedded in self-arranged matricesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2008K. Rumpf Abstract The investigated nanoscopic system, consisting of a non magnetic host material and precipitated ferromagnetic nanostructures shows a magnetic behaviour correlated to the size and shape of the deposited particles but also to their spatial distribution within the template which modifies the magnetic interactions between them. The nanostructures are deposited electrochemically into an etched silicon wafer exhibiting an array of channels of a few ten nanometers in diameter and a length up to 50 µm. The self-assembled grown templates offer the opportunity of tuning the magnetic properties by varying the geometrical characteristics of the membrane which can be loaded with different metals like Ni or Co with variable metal distribution. Magnetic characteristics like coercivity, magnetic anisotropy and temperature dependent magnetization give a survey about the structure and the magnetic interactions of the nanocomposite. This achieved ferromagnetic nanocomposite system is not only of interest for basic research but also gives rise to applications in magneto-optics, spintronics and sensor application. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effects of organically modified clay loading on rate and extent of cure in an epoxy nanocomposite systemPOLYMER INTERNATIONAL, Issue 11 2008Sharon E Ingram Abstract BACKGROUND: Cloisite 30B was added to diglycidyl ether of bisphenol F and cured with diaminodiphenylsulfone to investigate how the organoclay influenced the extent of cure. RESULTS: A substantial increase in the extent of cure was found with the addition of Cloisite 30B, when lower cure temperatures were employed. Cloisite 30B at 2 wt% resulted in a 40 °C increase in glass transition temperature and an increase in the magnitude of the bending modulus even though a high level of intercalated material was detected. CONCLUSIONS: It was observed that the addition of Cloisite 30B to the epoxy system increased the level of cure in the polymer, and was particularly prominent at low cure temperatures. Copyright © 2008 Society of Chemical Industry [source] Shear-induced migration of nanoclay during morphology evolution of PBT/PS blendJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Joung Sook Hong Abstract In this study, we investigated clay migration and its localization in multiphase blend nanocomposite systems during the evolution of blend morphology to elucidate how a hydrodynamic stress and chemical affinity between the polymer and clay induce them. To observe the morphology evolution, a multilayered blend, alternatively superposed poly(butylenes terephthalate) (PBT) and polystyrene (PS)/clay films or PBT/clay and PS films, was subjected to homogeneous shear flow, 1 s,1. Furthermore, the morphology was observed at different shear rates 1 s,1. When the PBT/(PS/clay) multilayered blend is subjected to flow, the clay dispersed in the PS layer first migrates to the interface depending on the amount of applied strain. The clay at the interface causes the average drop size of blend morphology to become smaller and the blend morphology becomes more stable because of the coalescence suppression effect. As more shear is applied, the clay at the interface moves further into more compatible phase, PBT, although the viscosity of PBT is higher than PS. On the contrary, the clay in the PBT layer does not migrate to the PS phase at any shear rate, which means that its chemical affinity is strong enough to prevent shear-induced migration. The clay increases the viscosity of the PBT phase and results in a different morphology with a droplet, cocontinuous structure. As a result, when the clay is induced to migrate by hydrodynamic stress, it migrates into thermodynamically more stable positions at the interface or in the chemically more compatible phase, depending on the applied strain. Once it is located at a thermodynamically more stable position, it is difficult to push it out only by hydrodynamic stress. The location of clay is significantly affected by the morphology during evolution, which means that the blend morphology can control the droplet form and cocontinuous structure by control of the clay migration kinetics. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Rheology and Physical Characteristics of Synthetic Biodegradable Aliphatic Polymer Blends Dispersed with MWNTsMACROMOLECULAR MATERIALS & ENGINEERING, Issue 4 2010Seung Woo Ko Abstract PLA/PBAT blends and PLA/PBAT/MWNT nanocomposite systems were prepared via a melt mixing process to examine their thermal and rheological properties. To compare the polymer blend/MWNT nanocomposite with a pure polymer/MWNT nanocomposite, PLA/MWNT, PBAT/MWNT, and PLA/PBAT/MWNT nanocomposite systems were prepared. TEM and SEM were used to observe that one phase has better affinity with the MWNT, while the MWNT was found to increase both the thermal properties of the PLA/PBAT blends and rheological properties of the PLA/PBAT/MWNT nanocomposite with distinct shear-thinning behavior due to the addition of the MWNT. An increase in the storage (G,) and loss (G,) moduli for the PLA/PBT/MWNT nanocomposite was also observed. [source] Hybrid metal/silicon nanocomposite systems and their catalytic activityPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2009Sergej Polisski Abstract In this work we studied the reduction of metal salts and their mixtures on extended hydrogen-terminated porous silicon surfaces. For these experiments we employed salts of Au, Ag, Pt and their mixtures. We show that the size and shape of resulting metal and metal alloy nanoparticles depends on the pore morphology. This has been confirmed by transmission electron microscopy measurements and plasmon resonance experiments. Finally we demonstrate catalytic activity of formed Pt nanoparticles in PSi matrix via monitoring the conversion of carbon monoxide. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] A short review on rubber/clay nanocomposites with emphasis on mechanical propertiesPOLYMER ENGINEERING & SCIENCE, Issue 11 2007R. Sengupta The invention of Nylon-6/clay nanocomposites by the Toyota Research Group of Japan heralded a new chapter in the field of polymer composites. This article highlights the work done in the field of rubber/clay nanocomposites. The preparations of rubber/clay nanocomposites by solution blending, latex compounding, and melt intercalation are covered and a thorough discussion of the mechanical properties of the various rubber/clay nanocomposite systems is presented. Other properties such as barrier, dynamic mechanical behavior, and thermal properties are also discussed. Finally, the future trends in the rubber/clay nanocomposites are mentioned. POLYM. ENG. SCI., 47:1956,1974, 2007. © 2007 Society of Plastics Engineers [source] Preparation and characterization of PBT nanocomposites compounded with different montmorillonitesPOLYMER ENGINEERING & SCIENCE, Issue 6 2004Domenico Acierno Because of their superior mechanical and thermal properties, light weight, and favorable cost/performance ratio, nanocomposite materials appear to be suitable replacements for metals and alloys in many industrial applications in fields such as automotive, structural plastics, electronics, packaging, and so on (1). The technological relevance of this large-scale market for polymers is evidenced by the numerous patents issued over the last few years, even though only few applications have entered the market. Polymer-clay nanocomposite systems were successfully prepared by melt compounding using several thermoplastic matrices (polyamides, polyolefins, etc.), but few data are reported in the scientific literature on polyester-based nanocomposites (2). Because of the high commercial relevance of polyesters, we have investigated the effect of organoclay inclusion on the structure and properties of these hybrid systems. In particular, we have studied the relationships between processing conditions, hybrid composition (organoclay type and content), nanoscale morphology and properties of poly(butylene terephthalate) (PBT) nanocomposites based upon several commercial organo-modified montmorillonites at different weight percentages. The melt compounding was performed using a twin-screw extruder, at extrusion rates of 90 or 150 rpm. Polym. Eng. Sci. 44:1012,1018, 2004. © 2004 Society of Plastics Engineers. [source] Fabrication of Luminescent CdS Nanoparticles on Short-Peptide-Based Hydrogel Nanofibers: Tuning of Optoelectronic PropertiesCHEMISTRY - A EUROPEAN JOURNAL, Issue 28 2009Goutam Palui Abstract The pH-induced self-assembly of three synthetic tripeptides in water medium is used to immobilize luminescent CdS nanoparticles. These peptides form a nanofibrillar network structure upon gelation in aqueous medium at basic pH values (pH,11.0,13.0), and the fabrication of CdS nanoparticles on the gel nanofiber confers the luminescent property to these gels. Atomic force microscopy, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy clearly reveal the presence of CdS nanoparticles in a well-defined array on the gel nanofibers. This is a convenient way to make organic nanofiber,inorganic nanoparticle hybrid nanocomposite systems. The size of the CdS nanoparticles remains almost same before and after deposition on the gel nanofiber. Photoluminescence (PL) measurement of the CdS nanoparticles upon deposition on the gel nanofibers shows a significant blue shift in the emission spectrum of the nanoparticles, and there is a considerable change in the PL gap energy of the CdS nanoparticles after immobilization on different gel nanofibrils. This finding suggests that the optoelectronic properties of CdS nanoparticles can be tuned upon deposition on gel nanofibers without changing the size of the nanoparticles. [source] | |||||||||||||