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Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Généralités, General, Alliage base aluminium, Aluminium base alloys, Alliage rapidement solidifié, Rapidly solidified alloy, Aleación rapidamiento solidificado, Rasch erstarrte Legierung, Chrome, Chromium, Cromo, Chrom, Cinétique, Kinetics, Cinética, Kinetik, Hydrogène, Hydrogen, Hidrógeno, Wasserstoff, Microstructure, Microestructura, Mikrogefuege, Solidification rapide, Rapid solidification, Solidificación rápido, Rasches Erstarren, aluminum-chromium alloys, hydrogen, rapid solidification, and thermal desorption spectroscopy

The thermal desorption spectroscopy has been applied to analyze hydrogen desorption from foils of Al-Cr alloys containing up to 3.0 mol% Cr produced by centrifugal melt quenching. Surface morphology of the alloys was monitored using atomic force microscopy and scanning electron microscopy. It was revealed that hydrogen behavior is strongly affected by microstructural features available due to rapid solidification and represents at least four hydrogen trap sites in Al-Cr alloys. The interstitial lattice sites adjacent to solute Cr atoms are identified as predominant trap site. The occupancy of dislocations was estimated to be rather high in contrast to vacancies and pores in alloys. The amount of hydrogen trapped by vacancies is drastically decreased with increase in Cr concentration. These hydrogen/microstructure interactions were discussed regarding rapidly solidified pure aluminum as well as traditionally processed aluminum samples.

Geology, Géologie, Geophysics, Géophysique, Sciences exactes et technologie, Exact sciences and technology, Terre, ocean, espace, Earth, ocean, space, Sciences de la terre, Earth sciences, Géochimie, Geochemistry, Roches cristallines, Crystalline rocks, Pétrologie des roches ignées et métamorphiques, phénomènes volcaniques, magmas, Igneous and metamorphic rocks petrology, volcanic processes, magmas, Asie, Asia, Analyse quantitative, quantitative analysis, Análisis cuantitativo, Cinétique, kinetics, Cinética, Corrélation, correlation, Correlación, Cristal, crystals, Cristallisation, crystallization, Cristalización, Croissance cristalline, crystal growth, Crecimiento cristalino, Densité, density, Densidad, Distribution dimension, size distribution, Ejecta, ejecta, Erreur, errors, Error, Eruption, eruptions, Erupción, Etude expérimentale, experimental studies, Forme cristalline, crystal form, Forma cristalina, Liquidus, liquidus, Magma, magmas, Matière fondue, melts, Producto fundido, Microlite cristal, microlite crystals, Nucléation, nucleation, Nucleación, Pression, pressure, Presión, Précision, accuracy, Precisión, Reproduction, reproduction, Reproducción, Style, style, Taux croissance, growth rates, Température, temperature, Temperatura, Texture, textures, Textura, effective undercooling, experimental replication of crystals, nucleation and growth rates, quantification of groundmass microlite, and rate and style of magma ascent

This paper reviews the principles and the methods used to investigate the ascent process of water-saturated magmas based on crystal texture and composition, which are especially relevant to recent progress made in decompression experiments. The primary cause of syneruptive crystallization is an increase in the liquidus temperature and resultant undercooling due to a decrease in dissolved H2O in the melt. Analyses of ejecta crystal texture provide time-resolvable information. Firstly, recent decompression experiments have improved knowledge regarding crystallization kinetics and have confirmed correlations made between ascent conditions, texture and crystal composition. The number density of groundmass microlite, crystal size distribution, and crystal form all reflect effective undercooling (A Teff). This increases with an increased pressure drop (AP), and also with an increased decompression rate (A P/At). If AP or AP/At match in an experiment series, we can compare the texture of the run products with respect to the other parameters. The experiments confirmed that the rates of crystal growth and nucleation show classical bell-shaped curves with ΔTeff. Growth rate reaches a peak at a lesser ΔTeff than for nucleation. Variation of ΔTeffcauses a shift in crystallization style. Secondly, decompression experiments help in estimation of the rate and style of magma ascent during a specific eruption through replication of crystals found in ejecta. To best reproduce natural ascent conditions one needs to know a) the number of syneruptive ascent stages, each of which can be assigned an approximate constant speed, b) temperature and pressure of magma at the start and end of each ascent stage, c) how texture evolved during the syneruptive ascent. Ascent conditions are estimated for each stage based on the experimental reproduction of the texture and composition of the natural ejecta. Accuracy in the estimation of ascent rate is thus influenced by errors in quantitative analysis of natural ejecta and the correlation of the decompression rate with textural parameters. Such experimental approaches improve our interpretation of eruption mechanisms by enabling us to combine observation made upon the eruptive product and time-resolved geophysical data. The application of this approach to the 2000 A.D. eruption of Usu Volcano in Japan is presented. With further improvement in the experimental techniques both laboratory and observational studies on ejecta will play a more important role in linking various volcanology research fields.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Physicochimie des réactions induites par rayonnements, particules et ultrasons, Physical chemistry of induced reactions (with radiations, particles and ultrasonics), Photochimie, Photochemistry, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères et rayonnements, Polymers and radiations, Propriétés et caractérisation, Properties and characterization, Adsorption, Adsorción, Cinétique, Kinetics, Cinética, Couche adsorbée, Adsorbed layers, Couche monomoléculaire, Monolayer, Capa monomolecular, Dépôt par oxydoréduction, Electroless plating, Depósito por oxidorreducción, Désorption liquide solide, Liquid solid desorption, Desorción líquido sólido, Etude expérimentale, Experimental study, Estudio experimental, Iminium composé, Iminium compounds, Iminio compuesto, Nickelage, Nickel plating, Niquelado, Particule chargée, Charged particle, Partícula cargada, Particule sous micronique, Submicron particle, Partícula submicrónica, Particule sphérique, Spherical particle, Partícula esférica, Photodimérisation, Photodimerization, Fotodimerización, Photolithographie, Photolithography, Fotolitografía, Polycation, Policatión, Pyridine dérivé, Pyridine derivatives, Piridina derivado, Résist négatif, Negative resist, Resistencia negativa, Résist positif, Positive resist, Resistencia positiva, Site spécifique, Site specificity, Sitio específico, Styrène polymère, Styrene polymer, Estireno polímero, Adsorbed Monolayer, Electroless Plating /, Interfacial Science, Microsphere, Patterning, and Photochemistry

Electrostatically adsorbed single-layered organic films exhibiting desorption-resistance toward deionized water were formed on a negatively charged substrate surface from multivalent cationic adsorbate molecules possessing plural pyridinium groups as adsorption sites. UV-visible transmission absorption spectroscopy, contact angle measurement, and zeta potential measurement suggested that promotion and suppression of the desorption-resistance were brought about by photochemical dimerization and decomposition of the adsorbate molecules on the substrate due to an increase and a decrease of the number of adsorption sites per adsorbate molecule. Based on the photoinduced alteration of the desorption-resistance, we proposed novel negative- and positive-type photopatterning methods of the adsorbed monomolecular film. We demonstrated here that polystyrene particles charged either negatively or positively could be adsorbed site-selectively and selective electroless nickel plating was caused in accordance with a shape of photopatterned monolayers.

Civil engineering, Génie civil, Geophysics, Géophysique, Climatology, meteorology, Climatologie, météorologie, Sciences exactes et technologie, Exact sciences and technology, Terre, ocean, espace, Earth, ocean, space, Geophysique externe, External geophysics, Météorologie, Meteorology, Physique des nuages, Cloud physics, Cinétique, Kinetics, Cinética, Cirrus, Cirro, Dissipation thermique, Thermal dissipation, Disipación térmica, Nuage stratiforme, Stratiform cloud, Nube estratiforme, Perturbation atmosphérique, Atmospheric disturbance, Perturbación atmosférica, Physique nuage, Cloud physics, Física nube, Troposphère, Troposphere, Troposfera, Variation temporelle, Time variation, Variación temporal, Zone tropicale, Tropical zone, and Zona tropical

TBB variation in dissipating upper-tropospheric stratiform clouds is investigated. TBB of upper tropospheric stratiform clouds generally increase with time. The variations of TBB of stratiform clouds have no seasonality and no difference is observed between daytime and nighttime. Larger increase of TBB is observed in the stratiform clouds with higher TBB. In some cases, TBB decrease with time. Characteristics of the decrease of TBB in the stratiform cloud also is investigated. The maximum rate of TBB decrease is about -10 K/hr. TBB decreases are occurred in a part of upper-tropospheric stratiform cloud having a horizontal scale on the order of hundred kilometers. In other part of stratiform clouds, TBB generally incresse with time. TBB decreases have no seasonality and were observed all over the analyzed area. Decrease of the TBB are not fixed in local time.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères organiques, Organic polymers, Réactions et propriétés chimiques, Chemical reactions and properties, Dégradation, Degradation, Allylique dérivé polymère, Allyl resin, Alílico derivado polímero, Cinétique, Kinetics, Cinética, Constante vitesse, Rate constant, Constante velocidad, Dégradation thermique, Thermal degradation, Degradación térmica, Energie activation, Activation energy, Energía activación, Etude expérimentale, Experimental study, Estudio experimental, Mélange hétérogène, Heterogeneous mixture, Mezcla heterogénea, Mélange polymère, Polymer blends, Phénylène oxyde(diméthyl) polymère, Phenylene oxide(dimethyl) polymer, Fenileno óxido (dimetil) polímero, Polymère linéaire, Linear polymer, Polímero lineal, Polymère réticulé, Crosslinked polymer, Polímero reticulado, Triazine dérivé polymère, Triazine derivative polymer, Triazina derivado polímero, Triallylisocyanurate polymère, Polymer Alloy, Polyphenylene Ether, Reaction-Induced Phase Separation /, and Thermal Degradation

The thermal degradation process of Poly(phenylenne ether) (PPE)/Triallylisocyanurate (TAIC) alloy was investigated. The alloy creates a bi-continuous phase during reaction-induced phase separation. PPE has high thermal stability due to rearrangement of main chain. Several kinetics data such as activation energies, 1 st order kinetic expression, and reaction constants show that mixing with TAIC accelerated thermal degradation of PPE. Monomeric compound analysis of thermal degradation by Py-GC/MS shows that the amount of 3,5-dimethylphenol in PPE/TAIC is 3-times as much as that in PPE. This is due to the fact that TAIC-graft-PPE is difficult to rearrange as regards main chain and main chain scission of PPE is likely.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Matériaux composites, Composites, Cinétique, Kinetics, Cinética, Durcissement(matière plastique), Curing(plastics), Endurecimiento(material plástico), Epoxyde résine, Epoxy resin, Epóxido resina, Etude expérimentale, Experimental study, Estudio experimental, Guanidines, Guanidinas, Gélification, Gelation, Gelificación, Matériau hybride, Hybrid material, Material híbrido, Silice, Silica, Sílice, Dicyandiamide /, Epoxy, Hybrid Material, and Network Structure

The gelation and network structures of an epoxy/silica hybrid system containing epoxy, dicyandiamide (DICY), and alchoxysilane were studied. The relationship between their network structures and gelation points can be described by a simple model. If the group number of used epoxys and the content of alchoxy silane were given, we would obtain the gelation time. The gelation time of the epoxy/silica hybrid system that contains y-glycidoxypropyltrimethoxysilane (GPTMS) and phenyltriethoxysilane (PTES) was extended. Results agreed with the predicted ones.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Fibres et fils, Fibers and threads, Propriété biologique, Biological properties, Propiedad biológica, Biodégradabilité, Biodegradability, Biodegradabilidad, Biosynthèse, Biosynthesis, Biosíntesis, Butyrate(hydroxy) polymère, Butyrate(hydroxy)polymer, Butirato(hidroxi) polímero, Cinétique, Kinetics, Cinética, Cristallinité, Crystallinity, Cristalinidad, Cristallisation isotherme, Isothermal crystallization, Cristalización isotérmica, Dégradation enzymatique, Enzymatic digestion, Degradación enzimática, Etude expérimentale, Experimental study, Estudio experimental, Fibre synthétique, Synthetic fiber, Fibra sintética, Film polymère, Polymer films, Morphologie, Morphology, Morfología, Polymère orienté, Oriented polymer, Polímero orientado, Propriété mécanique, Mechanical properties, Propiedad mecánica, Relation structure propriété, Property structure relationship, Relación estructura propiedad, Structure cristalline, Crystalline structure, Estructura cristalina, Effet taux étirage, Biodegradability /, Cold-Drawing, High- Ordered Structure, Hot-Drawing, Mechanical Properties, Planar Zigzag Conformation, Poly([R]-3-hydroxybutyrate), Single Crystals, Two-Step Drawing, and Ultra-High-Molecular-Weight

Poly([R]-3-hydroxybutyrate) (P(3 HB)) is accumulated by a wide variety of microorganisms as intracellular carbon and energy material, and is extensively studied as a biodegradable and biocompatible thermoplastic. However, the mechanical properties of P(3 HB) homopolymer films markedly deteriorate by secondary crystallization. Recently, we succeeded in obtaining strong P(3 HB) films and fibers by cold-drawing and two-step drawing procedures. The tensile strength of P(3 HB) fiber is over 1.3 GPa. The improvement of mechanical properties is due not only to the orientation of molecular chains but also to the generation of a zigzag conformation and network structure formed by fibril and lamellar crystals. The mechanical properties remained unchanged for 6 months. These strong films and fibers were completely degraded in natural river freshwater within 4 weeks. The rate of erosion of P(3 HB) films was controlled by the crystallinity of materials. P(3 HB) single crystals were prepared from a dilute solution by isothermal crystallization. Adsorptions of PHB depolymerase on P(3 HB) single crystals were examined using an immuno-gold labeling technique. The results demonstrated a homogeneous distribution of enzymes on the surface of crystals. Enzymatic degradation of single crystals progressed from the edge of the crystals, or along their long axis while making small fragments.

Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Metaux. Metallurgie, Metals. Metallurgy, Transformation de matériaux métalliques, Production techniques, Traitements de surface, Surface treatment, Dépôt de métaux et d'alliages, Metallic coatings, Cinétique, Kinetics, Cinética, Kinetik, Cuivre, Copper, Cobre, Kupfer, Dépôt électrolytique, Electrodeposition, Depósito electrolítico, Elektroplattieren, Impédance, Impedance, Impedancia, Modélisation, Modeling, Modelización, Mécanisme, Mechanism, Mecanismo, Revêtement métallique, Metal coating, Revestimiento metálico, Metallischer Ueberzug, Simulation numérique, Numerical simulation, Simulación numérica, Traitement surface, Surface treatment, Tratamiento superficie, and Oberflaechenbehandlung

Copper electrodeposition in a gel electrolyte has been studied by an electrochemical impedance spectroscopy (EIS). The electrochemical impedance was measured in a gel electrolyte containing various chloride concentrations. An inductive loop and a second capacitive loop were described on the Nyquist plot of electrochemical impedance at low frequency. These are called Faradaic impedance, which originates from the elementary steps of an electrode reaction. Warburg impedance was observed at low frequency in the diffusion limiting current region, indicating the contribution of the Cu(II) diffusion from the solution bulk to the electrode surface. The electrodeposition model of copper in the gel electrolyte was proposed on the basis of above-mentioned results. The numerical simulations were performed to confirm the proposed electrodeposition model and to obtain the kinetic parameters. Moreover, the influence of chloride was discussed from the obtained kinetic parameters.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères organiques, Organic polymers, Propriétés et caractérisation, Properties and characterization, Propriétés des solutions et des gels, Solution and gel properties, Structure moléculaire, Molecular structure, Estructura molecular, Acrylamide dérivé polymère, Acrylamide derivative polymer, Acrilamida derivado polímero, Cinétique, Kinetics, Cinética, Densité réticulation, Crosslink density, Densidad reticulado, Etude expérimentale, Experimental study, Estudio experimental, Gel colloïdal, Colloidal gel, Gel coloidal, Gonflement, Swelling, Inflamiento, Hétérogénéité, Heterogeneity, Heterogeneidad, Polymérisation radicalaire, Free radical polymerization, Polimerización radicalar, Rayonnement gamma, Gamma radiation, Radiación gama, Relation mise en œuvre structure, Structure processing relationship, Relación puesta en marcha estructura, Relation structure propriété, Property structure relationship, Relación estructura propiedad, Réticulation radiochimique, Radiochemical crosslinking, Reticulación radioquímica, Acrylamide(N-isopropyl) polymère, Dynamic Light Scattering, Gel, Inhomogeneity, Network, Poly(N-isopropylacrylamide), Shrinking, Small Angle Neutron Scattering, and γ-Ray /

The spatial inhomogeneities, characteristic of polymer gels, in poly(N-isopropylacrylamide) (PNIPA) gels were evaluated as functions of the gel preparation temperature, Tprep, and the cross-link concentration, Cx. The conventional monomer cross-linking and the γ-ray irradiation methods were employed in order to explore the role of cross-linking in the swelling/deswelling kinetics and microscopic structure. The rapid shrinking was achieved when a gel was formed at low cross-linking density and/or prepared at high temperature, irrespective of the way of cross-linking. A difference between two types of inhomogeneities appeared when the light or neutron scattering intensity for static contribution was compared for the two types of gels as a function of cross-linking density. Due to differences of monomer reactivity ratio and formation of microgel clusters, the monomer cross-linking gels exhibited extraordinarily strong scattering behavior. Although this phenomenon is more or less related to frozen inhomogeneties in gelling system, one should be aware that the results include different physical meanings linked with the inhomogeneous structure inherent in cross-linking system.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères organiques, Organic polymers, Réactions et propriétés chimiques, Chemical reactions and properties, Dégradation, Degradation, Buta-1,4-diène copolymère, Butadiene-1,4 copolymer, 1,4-Butadieno copolímero, Butène copolymère, Butylene derivative copolymer, Buteno copolímero, Caoutchouc thermoplastique, Thermoplastic rubber, Caucho termoplástico, Cinétique, Kinetics, Cinética, Copolymère triséquencé, Triblock copolymer, Copolímero trisecuencia, Dégradation thermooxydante, Thermooxidative degradation, Degradación termooxidante, Etude comparative, Comparative study, Estudio comparativo, Etude expérimentale, Experimental study, Estudio experimental, SBS, SEBS, Stabilité thermique, Thermal stability, Estabilidad térmica, Styrène copolymère, Styrene copolymer, Estireno copolímero, Terpolymère, Terpolymer, Terpolímero, SBBS, Cross-Linking /, New Thermoplastic Styrene Block Copolymer, EBBS, and Thermal Stability

Styrene-butadiene block copolymer (SBS) is widely used for various areas as a representative thermoplastic elastomer, but it is liable to thermal degradation because it contains double bonds. There are lots of reports concerning the thermal stability of SBS; however there have been few studies of details such as the effects of 1,2-bond and 1,4-bond in part of polybutadiene on thermal degradation. So we studied the effect using three samples: SBS, SEBS whose 1,2-bond and 1,4-bond are both hydrogenated. and SBBS whose 1,2-bond is selectively hydrogenated. In this paper we report the effect of microstructure on cross-linking.

Chemical industry parachemical industry, Industrie chimique et parachimique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Propriétés et essais, Properties and testing, Divers, Miscellaneous, Carbonate polymère, Polycarbonate, Carbonato polímero, Cinétique, Kinetics, Cinética, Dégradation thermique, Thermal degradation, Degradación térmica, Etude expérimentale, Experimental study, Estudio experimental, Matériau revêtement, Coating material, Material revestimiento, Mécanisme réaction, Reaction mechanism, Mecanismo reacción, Polycondensation, Condensation polymerization, Policondensación, Revêtement protecteur, Protective coatings, Revestimiento protector, Réaction catalytique, Catalytic reaction, Reacción catalítica, Réparation, Repair, Reparación, Sodium carbonate, Sodio carbonato, Traitement chimique, Chemical treatment, Tratamiento químico, Autoréparation, Deterioration, Molecular weight, Polymer, and Self-repairing

Polymer reaction of polycarbonate (PC) as a model of active protective materials has been studied. The specimen molded by injection was decomposed with steam at 120°C and subsequently treated with Na2CO3 at 130°C for 22 days for a preliminary experiment. The molecular weight increased slightly by the treatment. The effects of the deterioration period, temperature, the amount of Na2CO3 and the polymerization methods on the recovery of molecular weight and the kinetics have been conducted. It suggested that 1 phenyl and phenoxy groups at the end of the polymer chains are indispensable to re-combine the ends, 2 the reaction rate of the specimen decomposed for a longer time was higher, 3 Na2CO3 could accelerate the recover reaction, and 4 the deterioration and the recover reactions co-exist. The system of the self-repair and the concept of passive protection and active protection are discussed. So-called intelligent materials are more sophisticated than the self-repairing materials studied here because the intelligent materials have the ability of understanding the reason as the definition of intelligent.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Industrie des polymeres, peintures, bois, Polymer industry, paints, wood, Technologie des polymères, Technology of polymers, Formes d'application et semiproduits, Forms of application and semi-finished materials, Matériaux composites, Composites, Propriété optique, Optical properties, Propiedad óptica, Cinétique, Kinetics, Cinética, Effet concentration, Concentration effect, Efecto concentración, Ethylène oxyde polymère, Ethylene oxide polymer, Etileno óxido polímero, Etude expérimentale, Experimental study, Estudio experimental, Matériau hybride, Hybrid material, Material híbrido, Matériau photosensible, Photosensitive material, Material fotosensible, Photochromisme, Photochromism, Fotocromismo, Polymère silicium, Silicon polymer, Polímero silicio, Procédé sol gel, Sol gel process, Procedimiento sol gel, Propriété dynamomécanique, Dynamic mechanical properties, Propiedad dinamomecánica, Préparation, Preparation, Preparación, Stabilité thermique, Thermal stability, Estabilidad térmica, Structure supramoléculaire, Supramolecular structure, Estructura supramolecular, Tungstène VI Oxyde, Tungsten VI Oxides, Wolframio VI Óxido, Hybrid Materials, Microstructure /, Poly(ethylene glycol), and Tungsten Bronze Structure

Hybrids incorporating triethoxysilane end-capped poly(ethylene glycol) (PEG) with tungsten oxide (WO3) were prepared by a sol-gel process involving ion exchange of sodium tungstate dihydrate. When the hybrid was irradiated with a low-pressure mercury lamp, the transmittance at 620 nm in the UV-Vis spectra decreased and the color changed from pale yellow to blue. This means that tungsten bronze structure was formed in the hybrids. This result was also proved by the wide-angle X-ray diffraction patterns. After the irradiation with UV light, the hybrids bleached with elapsed time in the dark. A broad peak at 1.5 nm-1 in small-angle X-ray scattering profiles was caused by the interference between terminated silica domains. With increasing amount of WO3 this peak disappeared and the intensity increased, and then a peak due to the interference between the WO3 clusters appeared at 4 nm-1. The storage modulus was increased with increasing amount of WO3. These results mean that the WO3 clusters formed and homogeneously dispersed in the PEG matrix reinforced the hybrids.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères organiques, Organic polymers, Réactions et propriétés chimiques, Chemical reactions and properties, Modifications chimiques, Chemical modifications, Catalyse acide, Acid catalysis, Catálisis ácida, Cinétique, Kinetics, Cinética, Désalkylation, Dealkylation, Desalquilación, Etude expérimentale, Experimental study, Estudio experimental, Forme cylindrique, Cylindrical shape, Forma cilíndrica, Gel colloïdal, Colloidal gel, Gel coloidal, Gonflement, Swelling, Inflamiento, Modification chimique, Chemical modification, Modificación química, Méthacrylate de butyle copolymère, Butyl methacrylate copolymer, Metacrilato de butilo copolímero, Méthacrylate de butyle polymère, Butyl methacrylate polymer, Metacrilato de butilo polímero, Méthacrylique acide copolymère, Methacrylic acid copolymer, Metacrílico ácido copolímero, Préparation, Preparation, Preparación, Gel core shell, and Méthacrylate de t-butyle copolymère

Cylindrical poly(t-butyl methacrylate) gels (GBM) and GBM with a small amount of methacrylic acid unit were prepared. When GBM with p-toluenesulfonic acid as an acid catalyst was placed in a heated alkyl acetate, which works as an acid acceptor, it started to swell from the outer surface and to deesterify at the same time. At the end of the reaction, the gel was divided into a swollen shell layer, which had been hardly deesterified, and an unswollen core part, which had been deesterified. The final core size was controlled by the diffusion rate of the solvent and deesterification rate. Accordingly, the core size depended on many factors such as acid concentration in GBM, reaction temperature, concentration and bulkiness of acid acceptor. When the gel capsule aged at 120°C for 1 h was used, the aged shell layer served as a permeation barrier for many chemicals including water. This suggests that the gel capsule obtained is useful for a drug carrier.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères organiques, Organic polymers, Préparation, cinétique, thermodynamique, mécanisme et catalyseurs, Preparation, kinetics, thermodynamics, mechanism and catalysts, Polymérisation, Polymerization, Oléfine polymère, Olefin polymer, Olefina polímero, Aluminium Composé organique, Aluminium Organic compounds, Aluminio Compuesto orgánico, Borane organique, Organic borane, Borano orgánico, Butène polymère, Butylene polymer, Buteno polímero, Cinétique, Kinetics, Cinética, Constante vitesse, Rate constant, Constante velocidad, Etude expérimentale, Experimental study, Estudio experimental, Hexène polymère, Hexene polymer, Hexeno polímero, Polymère vivant, Living polymer, Polímero viviente, Polymérisation catalyseur complexe, Complex catalyst polymerization, Polimerización catalizador complejo, Polymérisation solution, Solution polymerization, Polimerización solución, Propagation réaction, Reaction propagation, Propagación reacción, Silazane organique, Organic silazane, Silazano orgánico, Titane Composé organique, Titanium Organic compounds, Titanio Compuesto orgánico, Titane complexe, Titanium complex, Titanio complejo, Catalyseur site unique, and Octène polymère

1-Octene polymerization was conducted by [η1: η3-tert-butyl(dimethylfluorenylsilyl)amido]dimethyltitanium ([t-BuNSiMe2Flu]TiMe2) activated with tris(pentafluorophenyl)borane (B(C6F5)3) at -50°C in the presence of trioctylaluminum (Oct3Al). The polymer yield linearly increased with increasing polymerization time. The poly(1-octene) obtained showed narrow molecular weight distributions (Mw/Mn) of about 1.1. In addition, the number average molecular weight (Mn) of the polymer was proportional to the polymer yield. These results indicated that living polymerization of 1-octene proceeded with this catalyst system. The dependence of propagation rate on 1-octene concentration was investigated under various 1-octene concentrations in the polymerization of low conversion (< 10%). The Mn values at a certain polymerization time were independent of 1-octene concentrations, which indicated that the propagation rate was almost zeroth order in 1-octene. Polymerization of 1-butene and 1-hexene with this catalyst system also proceeded in a living manner, and their propagation rates were also independent of monomer concentration. 1-Octene polymerization was conducted by this catalyst system with various concentrations of B(C6F5)3. The polymer yield and Mn value did not depend on the [B(C6F5)3]/[Ti] ratio and the polymers with narrow Mw/Mn were obtained. The results indicated that the propagation rate was not affected by excess B(C6F5)3.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères organiques, Organic polymers, Propriétés et caractérisation, Properties and characterization, Propriétés des solutions et des gels, Solution and gel properties, Acrylamide dérivé polymère, Acrylamide derivative polymer, Acrilamida derivado polímero, Cinétique, Kinetics, Cinética, Effet température, Temperature effect, Efecto temperatura, Etude expérimentale, Experimental study, Estudio experimental, Gel colloïdal, Colloidal gel, Gel coloidal, Gonflement, Swelling, Inflamiento, Matériau poreux, Porous material, Material poroso, Morphologie, Morphology, Morfología, Polymérisation radicalaire, Free radical polymerization, Polimerización radicalar, Préparation, Preparation, Preparación, Structure interne, Internal structure, Estructura interna, Acrylamide(N-isopropyl) polymère, and Microgel

Thermosensitive porous N-isopropylacrylamide (NIPAM) gels are obtained by polymerizing at a temperature above the transition temperature of polyNIPAM (about 32°C). The porous gels composed of microgel particles and pores swell or shrink quickly in response to the change in temperature. However, the gels prepared with low cross-linker concentration are composed of non-porous structure, because the formation of nuclei to make microgel particles is insufficient. In this work, as a method to promote the formation of nuclei under such low concentrations of cross-linker, the preparation method by controlling the synthesis temperature in steps was examined. The synthesis temperature was kept at 20°C(lower than the transition temperature of polyNIPAM) for a desired period, and then increased quickly to 50°C. If one set the period of retention at 20°C adequately, the porous gels were obtained, and the swelling rate increased more than 10 times compared with rates for the gels prepared at a constant temperature of 50°C. Even in this method, however, a lower limit of cross-linker concentration to form the porous structure is found.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères et rayonnements, Polymers and radiations, Propriétés et caractérisation, Properties and characterization, Chaîne latérale, Side chain, Cadena lateral, Cinétique, Kinetics, Cinética, Composé azoïque, Azo compound, Compuesto azoico, Copolymère photosensible, Light sensitive copolymer, Copolímero fotosensible, Diffusion rotationnelle, Reorientation diffusion, Difusión rotacional, Effet photoinduit, Photoinduced effect, Efecto fotoinducido, Etude expérimentale, Experimental study, Estudio experimental, Matériau photosensible, Photosensitive material, Material fotosensible, Méthacrylate d'éthyle polymère, Ethyl methacrylate polymer, Metacrilato de etilo polímero, Méthacrylate de méthyle polymère, Methyl methacrylate polymer, Metacrilato de metilo polímero, Polymère dopé, Doped polymer, Polímero dopado, Polymère photosensible, Light sensitive polymer, Polímero fotosensible, Rayonnement polarisé, Polarized radiation, Radiación polarizada, Réorientation moléculaire, Molecular reorientation, Reorientación molecular, Styrène copolymère, Styrene copolymer, Estireno copolímero, Styrène dérivé copolymère, Styrene derivative copolymer, Estireno derivado copolímero, Styrène polymère, Styrene polymer, Estireno polímero, Uréthanne polymère, Polyurethane, Uretano polímero, Azo-Dyes, Free Volume, Isomerization, Orientation Factor, Photoinduced Reorientation, Polarized FT-IR, Rotational Diffusion, and Surface Plasmon Spectroscopy /

Important factors controlling a polarized-light induced orientation of azo-dyes in a polymer matrix were studied by polarized spectroscopies, i.e., polarized FT-IR, polarized UV-vis, and surface plasmon spectroscopy. In polymer matrices dispersing azo-dyes, polar groups or free volume in polymers were found to contribute to the isomerization process of azo-molecules and the photoinduced anisotropy ratio by the evaluation of orientation factors. In the polymer linked with an azo-dye, higher orientation was observed. This is due to the suppression of the rotational diffusion by linkage with a polymer chain, which causes gradual reorientation during frequent trans-cis-trans isomerization cycles. In thin polymer films, the reorientation was observed in the direction normal to the film plane.

Chemical industry parachemical industry, Industrie chimique et parachimique, Metallurgy, welding, Métallurgie, soudage, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Terre, ocean, espace, Earth, ocean, space, Sciences de la terre, Earth sciences, Roches cristallines, Crystalline rocks, Pétrologie des roches ignées et métamorphiques, phénomènes volcaniques, magmas, Igneous and metamorphic rocks petrology, volcanic processes, magmas, Géologie de l'ingénieur et de l'environnement. Géothermie, Engineering and environment geology. Geothermics, Risques naturels: prévisions, dommages, etc, Natural hazards: prediction, damages, etc, Amérique du Nord, North America, America del norte, Asie, Asia, Avalanche clastique, debris avalanches, Cinétique, kinetics, Cinética, Dynamique, dynamics, Dinámica, Effondrement, collapse, Eruption, eruptions, Erupción, Flottation, flotation, Flotación, Frottement, friction, Modèle, models, Modelo, Mécanisme, mechanism, Transport, transport, Transporte, Vitesse, velocity, Velocidad, Volcan, volcanoes, Volcán, Volcanisme, volcanism, and Pression dynamique

Volcanic debris avalanche is a large-scale landslide which occurs at unstable volcanic edifice and often creates horseshoe-shaped crater at its source with hummocky deposits of volcanic debris including large blocks inside. Dynamic pressure model has recently been proposed to explain flow behavior of volcanic debris avalanches : Kinetic friction of debris avalanche decreases systematically at threshold of a certain critical speed for flotation. We have done a sliding experiment using flour powder as debris avalanche matrix and metal disks that slide on a powder layer as incorporated large blocks. Sliding traces left on a powder layer showed that a disk was floating over a certain critical speed. Kinetic friction coefficients, calculated by the position of a sliding disk recorded on a digital video, become small at a higher speed which exceeds critical floating speed, and provide smaller coefficient than those of normal surface of a rigid body. The critical floating speed deduced from dynamic pressure model is consistent with our experiment. In order to verify this model as the major driving force to float megablocks incorporated commonly in a volcanic debris avalanche, critical floating speeds for two geological cases at the collapses of 1980 Mount St. Helens and 1984 Ontake, central Japan, are examined and compared with the observed flow velocities. Estimated velocities deduced from the dynamic pressure model correspond fairly well to the actual velocities. This strongly suggests that the model gives the most convincing explanation for transportation and deposition mechanism of volcanic debris avalanche.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères organiques, Organic polymers, Propriétés et caractérisation, Properties and characterization, Propriétés des solutions et des gels, Solution and gel properties, Acrylamide dérivé polymère, Acrylamide derivative polymer, Acrilamida derivado polímero, Cinétique, Kinetics, Cinética, Contraction, Contracción, Effet température, Temperature effect, Efecto temperatura, Etude expérimentale, Experimental study, Estudio experimental, Gel colloïdal, Colloidal gel, Gel coloidal, Gonflement, Swelling, Inflamiento, Matériau poreux, Porous material, Material poroso, Polymérisation phase hétérogène, Heterogeneous polymerization, Polimerización fase heterogénea, Polymérisation radicalaire, Free radical polymerization, Polimerización radicalar, Relation mise en œuvre propriété, Property processing relationship, Relación puesta en marcha propiedad, and Acrylamide(N-isopropyl) polymère

Effects of the synthesis temperature and the cross-linker concentration on the formation of thermosensitive N-isopropylacrylamide (NIPAM) porous gels which swell or shrink quickly in response to the change in temperature were examined systematically. The swelling and shrinking properties of the porous gels were also examined. Although phase separation occurs by polymerizing NIPAM at the temperatures above the transition temperature of polyNIPAM (about 32°C), with increasing the cross-linker concentration a structure composed of aggregated microgel particles and pores, i.e. the porous gel, was formed. The swelling rate of such a porous gel was extremely large compared with that of a non-porous gel prepared with low concentration of cross-linkers. The swelling rate of gel composed of fully developed porous structure was almost inversely proportional to the square of the characteristic length of the gel in the swollen state. On the other hand, the shrinking of the gel was very fast compared with the swelling, and the gel prepared with a low concentration of cross-linker also shrank very fast, as did a porous gel prepared with a high concentration of cross-linker. The similarity is due to the fact that the gel prepared with a low concentration of cross-linker is also composed of a percolate structure formed by a phase separation, namely a porous structure, in the swollen state of the initial stage of shrinking process.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères et rayonnements, Polymers and radiations, Polymérisation, Polymerization, Acide Brönsted, Brönsted acid, Acido Bronsted, Acrylate polymère, Acrylate polymer, Acrilato polímero, Activité amorceur, Priming activity, Actividad trampa, Ammonium quaternaire composé, Quaternary ammonium compound, Amonio cuaternario compuesto, Amorceur cationique, Cationic catalyst, Iniciador catiónico, Amorçage, Breakdown initiation, Cebamiento, Bore Composé organique, Boron Organic compounds, Boro Compuesto orgánico, Cinétique, Kinetics, Cinética, Diépoxyde, Diepoxide, Diepóxido, Ether cyclique polymère, Cyclic ether polymer, Eter cíclico polímero, Etude comparative, Comparative study, Estudio comparativo, Etude expérimentale, Experimental study, Estudio experimental, Iodonium composé, Iodonium compounds, Iodonio compuesto, Mécanisme réaction, Reaction mechanism, Mecanismo reacción, Photoamorceur, Photoinitiator, Fotoiniciador, Photogénération, Photogeneration, Fotogeneración, Polymérisation cationique, Cationic polymerization, Polimerización catiónica, Polymérisation ouverture cycle, Ring opening polymerization, Polimerización abertura ciclo, Polymérisation photochimique, Photopolymerization, Polimerización fotoquímica, Rendement quantique, Quantum yield, Rendimiento quántico, Sulfonium composé, Sulfonium compound, Sulfonio compuesto, Vitesse réaction, Reaction rate, Velocidad reacción, Aromatic Ketone, Donor-Acceptor, Photogeneration of acid /, Quantum Yield, Radical Generation, Styryl Dye, and Visible Laser

Based on our recent studies on photoinitiator systems, two onium borates, onium butyltriphenylborates for radical photopolymerization and onium tetrakis(pentafluorophenyl)borates for cationic photopolymerization, are discussed. The onium butyltriphenylborates were photodecomposed by various sensitizers and generated free radicals to initiate radical polymerization of acrylates. The rate of photoporimerization (Rp) by the onium borates was a few hundred folds higher than that for the corresponding onium salt or borate initiators. The high Rp value for the onium borates is due to the fact that two free radical species are generated from both the onium cation and the borate anion of the onium borates. The onium tetrakis(pentafluorophenyl)borates initiated the photopolymerization of epoxides and vinyl ethers by both the direct photolysis and the sensitized photolysis using anthacene sensitizers. An acid generated by photodecomposition of the onium borates was thermally decomposed and formed neutral compounds. The photoinitiation process between onium borates and sensitizers is based on the photoinduced electron transfer reaction. It was proved that the more negative the free energy change of the photoinduced electron transfer reaction, the higher the Rp value of cationic polymerization.

Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Physicochimie des polymeres, Physicochemistry of polymers, Polymères organiques, Organic polymers, Préparation, cinétique, thermodynamique, mécanisme et catalyseurs, Preparation, kinetics, thermodynamics, mechanism and catalysts, Polymérisation, Polymerization, Activité catalytique, Catalyst activity, Actividad catalítica, Catalyseur complexe, Complex catalyst, Catalizador complejo, Cinétique, Kinetics, Cinética, Diisocyanate organique, Organic diisocyanate, Diisocianato orgánico, Energie activation, Activation energy, Energía activación, Equation vitesse, Rate equation, Ecuación velocidad, Etude expérimentale, Experimental study, Estudio experimental, Métal transition Complexe, Transition metal Complexes, Metal transición Complejo, Méthacrylate de méthyle polymère, Methyl methacrylate polymer, Metacrilato de metilo polímero, Polymère syndiotactique, Syndiotactic polymer, Polímero sindiotáctico, Polymérisation catalyseur complexe, Complex catalyst polymerization, Polimerización catalizador complejo, Polymérisation solution, Solution polymerization, Polimerización solución, Polymérisation stéréospécifique, Stereospecific polymerization, Polimerización estereoespecífica, Stéréospécificité, Stereospecificity, Estereoespecificidad, Synthèse chimique, Chemical synthesis, and Síntesis química

Various transition metal complexes were synthesized from an aliphatic diisocyanate, hexamethylene diisocyanate (HDI) which is a representative raw material of polyurethanes, and metal acetylacetonates. In the polymerization of methyl methacrylate (MMA), these catalysts were sufficiently active as polymerization catalyst. Transition metals such as cobalt, nickel, and copper were effective, but cobalt and copper were especially suitable. From a kinetic study using the cobalt complex, the polymerization rate (Rp) can be expressed as Rp=k [MMA]1.7[HDI-Co(acac))2]0.70. The overall activation energy of the polymerization was determined to be 50.8 kJ/mol. The polymerization did not occur in the presence of an inhibitor, indicating that the active species of polymerization was a free radical. The resulting polymers were rich in syndiotactic structure.