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Hydrogenation of carbon dioxide (CO2) on copper/zinc oxide-based catalysts was investigated using near-ambient pressure X-ray photoelectron spectroscopy (AP-XPS). An initial hydrogenation step of CO2 to formate was studied using Zn-deposited single-crystal Cu surfaces. CO2 activation on the model catalysts leads to the formation of carbonates (CO3) on the surface in the presence of near-ambient pressure CO2 and hydrogen (H2). The addition of a small amount of water to the feed gas enhances the hydrogenation of CO2 into formate. This indicates that hydroxyl produced through dissociative adsorption of water is a source for the CO2 hydrogenation observed under the present reaction conditions. We also performed operando spectroscopy of an industrial catalyst for methanol synthesis at higher pressure to reveal the chemical states of the catalyst and adsorbed intermediates during the catalytic reaction. In-situ formation of active catalytic sites was detected by operando hard X-ray photoelectron spectroscopy. Analysis of the reaction products in the presence of CO2 and H2 gases shows the formation of methanol and CO. The rate of methanol synthesis correlates with the dynamic changes in the chemical states of the catalyst, and the reaction intermediates adsorbed on the catalyst. [ABSTRACT FROM AUTHOR]

The studies about surface chemistry of formic acid on Cu-based model catalysts including our recent investigation are reviewed from the surface-science point of view. The Cu-based model catalysts including steps and Zn-deposition have been prepared using the well-defined single crystalline Cu surfaces. Formate species are formed by the decomposition from formic acid on the model catalysts surfaces. Various surface spectroscopies have been applied for the assignments of intermediate species, the quantitative estimation of their coverages and the kinetics of adsorbed species. The active sites and reaction mechanisms of the decomposition of formic acid and the hydrogenation of formate species are discussed. [ABSTRACT FROM AUTHOR]

This paper presents the results of technological development research to safely and efficiently reduce substances contained in combustion emissions, which may impair the growth of crops and the health of workers, below the permissible limit. There are carbon monoxide and nitrogen oxides. Agricultural crop production factories, including greenhouses and glass greenhouses, may use the combustion emissions of hydrocarbon fuels as a carbon dioxide source to promote photosynthesis. In this study, the upper limit concentration of chemical substances permitted for emissions of the gas-fired water heater was calculated by model calculation, and it was set as the target purification. (1) A system using catalyst and air dilution was constructed, and it was shown that the target purification was satisfied. (2) The constructed combustion emissions purification system was verified under automatic cultivation operation of lettuce for eating raw. It was confirmed that the quality and yield of the fertilization method were equivalent to those of the vaporization type carbon dioxide fertilization method, and that the system exerted its effect stably. [ABSTRACT FROM AUTHOR]

During the 4.6 billion years of history, the earth has repeatedly warmed and cooled. It is very common for the Polar Regions to have no ice. On the other hand, the theoretical surface temperature of the earth is -18 °C, and due to the presence of greenhouse gases in the atmosphere and their delicate balance, the average temperature is 15 °C, making it a comfortable environment for living things. It is recognized that the current global warming is clearly caused by human influence, even from the rate of temperature rise. Carbon recycling has been proposed as a means to stop this wanning. Since most of the current carbon dioxide emissions are generated by combustion of fuel, recycling to fuel would be the main course. This paper introduces recycling technology for methane, a typical fuel, and describes the ideal form of carbon recycling. [ABSTRACT FROM AUTHOR]

The objective of this study is to elucidate the formation and growth behavior of CO2 hydrate. Based on hydrate film thickness measurements, the process of hydrate film development was classified into "formation" and "growth". A macro-scale thickness prediction model based on mass transport was constructed for these processes. Molecular dynamics calculations were also introduced and combined with the macro-scale prediction model to construct a model capable of predicting film thickness. [ABSTRACT FROM AUTHOR]

We applied high hydrostatic and carbon dioxide pressure conditions to the production of Yudane-like bread. The advantages of the Yudane method are the unique texture and sweetness attributed to endogenous enzymes. We employed a hydrostatic pressure of 50 MPa at 30C, and a high carbon dioxide pressure of 1 MPa at 40°C. These high pressure conditions inhibited microbial growth but enabled enzymatic reactions. Increases were observed in reducing sugars, glutamic acid and water soluble proteins, and decreases were observed in gliadin and glutenin. The use of high-pressure conditions in breadmaking can contribute to a diversity of breadmaking processes. The biological effects of high pressure conditions and the reason why microbes are inactivated by these conditions are also discussed. [ABSTRACT FROM AUTHOR]

Copyright of Japanese Journal of Biometeorology is the property of Japanese Society of Biometeorology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Dissolution of gas into flowing water inside a porous medium is important in various hydrogeology processes, such as geological carbon sequestration (GCS). The dissolution rate of CO2 controls the amount of CO2 injection and the safety of the GCS process. In this report, we investigated the dissolution behavior of four gas species, i.e., CO2, O2, N2, and Ar, into flowing water inside a porous medium by using micro-tomography. The trapped gas characteristics can be observed, and thus interfacial area and mass transfer coefficient can be calculated. Compared with the other gases, we found that the dissolution behavior of CO2 gas is unique, and the mass transfer coefficient is one order of magnitude lower than other gases. We believe that the high dissolution ratio of CO2 gas could have generated a layer of the high solute region around the trapped CO2 gas, disrupting the mass transfer process.

Copyright of Journal of Home Economics of Japan is the property of Japan Society of Home Economics and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Ionic liquid exhibits outstanding performance for selective absorption of carbon dioxide(CO2). Ionic liquid electrospray for CO2 absorption has been proposed as a high performance CO2 absorption system. CO2 absorption is caused through chemical reactions at gas-liquid interface, thus generating smaller droplets leads to higher absorption efficiency. In this study, the effect of applied pulsed DC voltage on ionic liquid electrospray was experimentally clarified. By applying pulsed DC voltage, smaller droplets are ejected compared to applying continuous DC voltage. Applying pulsed voltage of 50 - 150 Hz increases the number of generated droplets more than twice of that for DC voltage. An improvement of CO2 absorption was clearly obtained when the frequency is in the range of 50 - 150 Hz. [ABSTRACT FROM AUTHOR]

Elucidating the sealing capacity of caprock is very important because CO2 sequestered in deep aquifers can remain there for several hundred years in the CO2 sequestration. Threshold capillary pressure is a key property affecting sealing capacity, and therefore, the ability to measure the threshold pressure of a target rock conveniently is highly sought after. In this study, data collected during the CO2 injection process in triaxial compression tests of mudstone supposed to be a caprock were used to measure threshold pressure via the dynamic method. These triaxial tests were conducted to study the mechanical properties of mudstone below depths of 1000 m. The threshold pressure for 23 out of 26 test samples was successfully measured. Measured values ranged from 0.54 to 1.57 MPa, which was within a reasonable range compared to the results reported by three other studies that used similar mudstone specimens. A small amount of shrinkage induced by a pore pressure decrease, which was caused by a threshold pressure, was observed in the experiment. The threshold pressure showed a positive correlation with the shrinkage, implying that this pressure might be estimated from the shrinkage. Thus, a volumetric elastic constant was calculated from the shrinkage assuming that the decrease in mean pore pressure was half of the threshold pressure. The mean volumetric elastic constant was 0.92 GPa, which was about 40% lower than that of the rocks from which the test samples were obtained. These results indicate that the shrinkage value cannot be directly used to estimate the threshold pressure, and that a correction of this shrinkage value is necessary.

Pushed by human activities, the atmospheric CO2 concentration has reached levels which have made extreme weather events more likely, and which threaten permanent climate changes for the world. In order to combat this, CO2 emissions must be reduced significantly. Electricity production and industry are two sectors which contribute greatly to the production of CO2, thus a reduction in the amount of CO2 produced by thermal power plants and factories could make a significant contribution to combatting climate change. The electrochemical reduction of CO2 in those sources is considered very likely to be a solution to the problem. In this study, the activity of a Pt oxide electrode in the electrochemical reduction of CO2 was investigated in a sulfuric acid solution. Pt oxide electrodes have shown superior activity for the methanol oxidation reaction, which is the reverse reaction of CO2 electrochemical reduction. Cyclic voltammetry of the Pt oxide electrode in a CO2-saturated H2SO4 solution showed a definite anodic peak at 0.6-0.8 V vs. SHE, which was not observed in an Ar-deaerated electrolyte. Thus, it was determined that the anodic peak could be related to the re-oxidation of the reduction product of CO2 during cathodic polarization. The activity of the Pt oxide electrode for CO2 reduction was much higher than that of the Pt electrode. It was concluded that the residual oxygen, which was hardly detected in the Pt electrode, improved the activity for CO2 electrochemical reduction on the Pt oxide electrode. Gas chromatography-mass spectrometry of the electrolytic solution after CO2 reduction revealed that the reduction product was mainly CH3OH. These results should be very useful for developing a new electrochemical reduction system for converting CO2 into CH3OH.

This study investigated an effective method to desorb CO2 from low-concentration (0.2 mol/L) monoethanolamine (MEA) solutions using calcium chloride (CaCl2) and ultrasound irradiation at 25 ºC. The pH value of the solution had a large influence on the desorption ratio of CO2 from MEA solution under ultrasound irradiation. CO2 was successfully desorbed up to pH8.2, and it was impossible to desorb CO2 at pH over 8.2. It was clarified that CO2 desorption by ultrasound irradiation is useful for the concentration of MEA solution of up to 2.0 mol/L, because the pH rises above 8.2 when the concentration of MEA solution is increased to above 2.0 mol/L. It also became evident that the addition of small amount of CaCl2 further increases the amount of CO2 desorbed during ultrasound irradiation.

We have researched the effect of micro-bubble CO2 injection and its mechanism toward the practical application of micro-bubble CO2 injection technology into Carbon Capture and Storage(CCS) and Enhanced Oil Recovery (EOR). In the first stage, we have carried out laboratory experiments and examined injection methods and developed tools as basic research. In the second stage, a field pilot test was conducted using a part of the Sarukawa oil field in Akita prefecture in order to verify the microbubble injection effect and mechanism evaluated based on basic research. In the test, the Huff and Puff method was adopted, CO2 injection for 10 days and flowback (production) for 7 days were carried out. The test is carried out by microbubble CO2 injection method and conventional CO2 injection method, and the test period is one month each. In the field test, the functionality of the tool was confirmed, that easy retrievableness in the well with slick line or wire line, the stable microbubble generation and injection, and the effect of the microbubble was evaluated as the improvement of CO 2 injectivity and storability. From the simulation model constructed based on the field test results, the mechanism of improving CO2 injectivity and storability was also evaluated. From these tests, it was confirmed that the microbubble injection technology can be applied in the field. [ABSTRACT FROM AUTHOR]

Belousov-Zhabotinsky (BZ) reaction is a typical example of chemical oscillation. For an application of BZ reaction to engineering, the downsizing of reaction field will be needed. We focus on liquid marble (LM) to solve this subject. LM is a stable sphere liquid covered with hydrophobic microparticles. We observed BZ reaction in LM to investigate the reaction property in small space. We succeeded in observing chemical oscillation for a long time in LM. During the observation, no bubble was produced although carbon dioxide is contained as reaction products. We found that LM tends to exhibit regular oscillation mode with a decrease in droplet size. In addition, the period of BZ reaction changes with the size. This can be explained from the effect of oxygen and the amount of particles covering a droplet. As a result, the oscillation period can be controlled by the droplet size and the amount of particles. [ABSTRACT FROM AUTHOR]

A 78-year-old man who was diagnosed as having hepatocellular carcinoma(segment 4/8)underwent laparoscopic hepatectomy. About 5 hours after the start of the operation, SpO2 and systolic blood pressure suddenly dropped to 87% and 40 mmHg. EtCO2 level decreased to 8 mmHg and PaCO2 was 48.5 mmHg. Based on the discrepancy between the PaCO2 and EtCO2, the patient was diagnosed as having pneumoperitoneum-induced carbon dioxide embolism. The surgical procedure was immediately interrupted and the patient was hyperventilated with pure oxygen. After surgical interruption, general status was recovered to the normal condition. We carefully restarted the operation and completed it laparoscopically. The patient was discharged from the hospital on the 15th day without any postoperative complications. Carbon dioxide embolization is a serious life-threatening complication that requires careful monitoring.

For integrated pest management（IPM）of strawberries in Miyagi Prefecture, Japan, combinations of applications of Phytoseiulus persimilis Athias-Henriot, Neoseiulus californicus（McGregor）, spiracle-blocking insecticides, fumigation using a high concentration of carbon dioxide, and an increase in UV-B radiation using a reflective sheet are currently in use for the control of spider mites. Efforts are underway to improve and expand on these methods. For the control of aphids, application of two natural enemies, Aphidius colemani Viereck and Ephedrus nacheri Quilis, in conjunction with banker plant system is highly effective, and their use is expected to increase over the next few years. For the control of thrips, application of selective pesticide at the initial time of their occurrence after installing red insect-proof nets（mesh size 0.8×0.8 mm）around the opening of the greenhouse is currently used. The possibility of using natural enemies against thrips, such as Haplothrips brevitubus（Karny）, Amblydromalus limonicus（Garman et McGregor）, and Amblyseius cucumeris（Oudemans）, needs further study. For the control of whiteflies, a tape formulation of pyriproxyfen and spiracle-blocking insecticides, as used in the control of spider mites, can maintain populations at a low density. Although there are difficulties in the use of entomopathogenic fungi and indigenous natural enemies due to the cold climate, we need to further examine their efficacity as IPM. [ABSTRACT FROM AUTHOR]

Enhanced oil recovery (EOR)and improved oil recovery (IOR) technologies have been applied to various oil and gas fields for many years. However, the environment for EOR/IOR has been severe in low oil price and increase of development cost and more effective and economical EOR technology is expected. We focused the application of micro bubble as cutting-edge EOR technology. Micro bubble technology has been applied to various industries as medical, agriculture and environment fields. And micro bubble has some characteristics in relative to the effect of EOR such as improvement of sweep efficiency and oil density and viscosity. We have studied about the efficiency of micro bubble technology and its mechanism from laboratory test and flow simulation. We evaluated the improvement of the sweep efficiency, solubility to oil and oil recovery by micro bubble injection from core flooding test which was one of the laboratory tests and it was indicated that the capillary pressure affected the injection area from flow simulation. We expect micro bubble technology will become useful as new EOR technology from our study. [ABSTRACT FROM AUTHOR]

In the development of reservoirs of natural gas dissolved in water and shale gas, knowledge of the adsorption behavior of natural gas on reservoir rock is crucial. Furthermore, it is reported that carbon dioxide, rather than methane, is selectively adsorbed on the clay minerals, which suggests a possible enhanced gas recovery by injection of carbon dioxide. This paper provides a technical discussion on the adsorption behavior of methane and carbon dioxide on mudstone samples. The adsorption tests of methane showed that the amount of adsorbed gas increases with increasing clay mineral contents in mudstone. The adsorption test of carbon dioxide showed that the amount of carbon dioxide adsorbed is five times larger than that of methane. The amount of methane and carbon dioxide adsorbed to mudstone was well predicted by Langmuir's adsorption isotherm. The adsorption tests of a mixture of methane and carbon dioxide showed that the amount of adsorbed methane and carbon dioxide depends on the partial pressure of each gas. As the partial pressure of carbon dioxide increased, the concentration of carbon dioxide in the absorption phase increased and that of methane decreased. Meanwhile, the amount of absorbed methane and carbon dioxide was also observed to be affected by the gas phase composition. As the concentration of carbon dioxide in the gas phase increased, the amount of methane adsorbed increased to a value more than that obtained in the ideal state. When the concentration of carbon dioxide in the gas phase decreased, the amount of carbon dioxide adsorbed decreased greatly from the value obtained in the ideal state. [ABSTRACT FROM AUTHOR]

Iron is an important nutrient in marine biogeochemical cycles because it limits primary production in high-nutrient, low-chlorophyll areas and nitrogen fixation rates in nitrogen-limited areas. Although three-dimensional biogeochemical cycle models were developed in the 1990s to evaluate oceanic carbon dioxide uptake, it was not until 2000 that such models considered iron cycling. This was mainly because of limited field data on iron, arising from difficulties in measuring dissolved iron. Early iron cycle models were developed from knowledge based on limited field data, and such models assumed that global-scale dissolved iron distribution was determined simply by iron supply from aeolian deposition and removal by scavenging via complexation with organic ligands. Subsequent accumulation of field data has revealed that various external sources, cycling of organic ligands, and colloidal aggregation can affect globaland basin-scale distributions of dissolved iron. In this paper, we review the history of the development of marine biogeochemical cycle models with a special focus on iron, and describe their current status and issues that must be addressed for further model improvement. Recent activity regarding the Iron Model Intercomparison Project is also described. [ABSTRACT FROM AUTHOR]

A method for the determining of solubility of methane and carbon dioxide in high-pressure water was developed by direct injection of the sample into a gas chromatograph column. Solubility was determined from the values obtained from the absolute calibration curve. This is a simple and quick method replacing a conventional method (flash method). Solubility of CH4 and CO2 was measured by this method and the high accuracy was confirmed compared to acquired data by flash method. [ABSTRACT FROM AUTHOR]

Star-shaped diblock copolymers consisting of poly(2-adamantyl vinyl ether) [poly(2-AdVE) as outer hard segments and poly[2-(2-methoxyethoxy) ethyl vinyl ether] [poly(MOEOVE)] having polar oxyethylene side chains as inner soft segments were synthesized by sequential living cationic polymerization. The star-shaped diblock copolymer, star-poly(2-AdVE)300-6-poly(MOEOVE)700-core，exhibited a tensile strength (7"b) Of 5.13 MPa and an elongation at break (£B) Of 340%. The gas permeability coefficients of carbon dioxide (PCO2) and the CO2 and N2 separation ratio (PCO2/PN2) of the star-poly(2-AdVE)300-Z7-poly(MOEOVE)700-core were 219 barrer and 40.1, respectively. Thus, the star-poly(2-AdVE)300- 6-poly(MOEOVE)700-core is a thermoplastic elastomer with excellent CO2 separation and good mechanical properties. [ABSTRACT FROM AUTHOR]

Ester-containing poly(diphenylacetylene) (2) was synthesized by substitution of CH3CO2 with bromoethyl groups in the side chains of the polymer (1). Hydrolysis of ester of 2 resulted in a polymer (3) with hydroxy groups. Thiol-containing polymer (5) was synthesized by hydrolysis of thiourea-containmg polymer (4). The carbon dioxide permeability coefficient (PCO2) and separation factor CPc02/PN2) of 2 were 230 barrer and 23, respectively. Polymer 3 showed good CO2 separation, and the Pqoi and Pcoi/Pm were 290 barrer and 26, respectively due to the suitable affinity of hydroxy groups to CO2. In contrast, polymer 5 showed lower permeability and selectivity, and the CO2 and PCO2/Pn2 were 130 barrer and 15, respectively. This can be explained by the fact that the presence of mercapto groups decreased CO2 diffusivity because of strong interaction of mercapto groups with CO2. [ABSTRACT FROM AUTHOR]

We carried out two-dimensional numerical simulation for downward Poiseulle water flow with a carbon-dioxide bubble or multiple carbon-dioxide bubbles in a vertical channel. A phase-field method was used for capturing the interface. The concentration equation including the phase-field function and the time evolution equation of the phase-field function including the velocity field were solved simultaneously by using Graphics Processing Units. The results showed that a bubble in the offset position moved away from the left-hand side wall, while it was rising, due to the lift force. This motion causes the development of asymmetrical, complicated structure of wake flow. Then, the bubble moved towards the wall due to the change in the flow velocity field. These time changes in the wake flow enhance the diffusion and absorption of carbon dioxide in flow. In the case of four bubbles, the decreasing rate of bubble mass is higher than that for a single bubble. This is partly because of the difference in the interface length, and partly because of the renewals both of the concentration boundary layer and the wake-flow structure caused by the impact of bubble coalescence. [ABSTRACT FROM AUTHOR]

PSA system for the recovery of carbon dioxide from blast furnace is examined. From the results of bench plant experimental operation, it was revealed that recovery cost of carbon dioxide was below 2,000 yen per ton. Further experimental operation to assure the commercial PSA system ongoing. [ABSTRACT FROM AUTHOR]

Poly(amidoamine) (PAMAM) dendrimers display quite high specificity toward CO2, and incorporation of the dendritic molecules in a polymer matrix has been investigated to fabricate CO2 separation membranes. Especially, photopolymerization of polyethylene glycol) dimethacrylate (PEGDMA) in the presence of the dendrimers allows forming macroscopically homogeneous membranes. The resulting membranes show excellent CO2 separation from H2 under high humidity, depending on the dendrimer concentration and fabrication. The morphology is studied in detail by various real-space and Fourier-space methods. For example, a laser-scanning confocal microscope observation reveals the formation of a bicontinuous phase structure of the dendrimer-rich and PEG-rich phases upon polymerization-induced phase separation on a couple of microns scale. The macrophase-separated structure is related to the CO2 separation performance. The mechanism of preferential CO2 separation is elucidated. CO2 partially turns into bicarbonate ions in the membrane under humid conditions, which would be the major migrating species, while the rest of the CO2 forms carbamate with primary amines of the PAMAM dendrimer to form a quasi-crosslinking, which would suppress the H2 permeation by a so-called "CO2-selective Molecular Gate". [ABSTRACT FROM AUTHOR]

In order to develop a novel controlled-release materials, we previously attempted to impregnate poly(L-lactide) (poly(L-LA)), poly(L-LA-ran-CL (CL: ε-caprolactone) and poly(L-LA-ran-TEMC) (TEMC: tetramethylene carbonate) with low boiling point organic compounds using supercritical carbon dioxide (scCO2) as the solvent. In this work, the factors influencing the impregnation of poly(L-lactic acid) copolymers with various compounds in scCO2 was investigated. The effects of temperature, pressure and time on the impregnation process were evaluated, using synthetic poly(L-LA-ran-CL), poly(L-LA-ran-TEMC) or poly(L-LA-ran-DXO) (DXO: 1,5-dioxepan-2-one) as the base polymers. Preparation of the controlled-release materials was carried out using essential oil from Thujopsis dolabrata vat. hondae in scCO2 at 14 MPa, 40°C for 3 h. The oil content was highest for poly(L-LAran-CL) and lowest for poly(L-LA-ran-DXO). The mechanical properties of those impregnated were evaluated by a tensile testing machine. Although the tensile strength and elastic modulus of poly(L-LA-ran-TEMC) and poly(L-LA-ran-DXO) increased greatly by impregnation in scCO2, the elongation decreased conversely. Poly(L-LA-ran-DXO) could easily be hydrolyzed in saturated calcium chloride solution, and the containing oil was also released earlier than for other polymers. [ABSTRACT FROM AUTHOR]

In this study, we report on the alternating copolymerization of carbon dioxide and cyclohexene oxide by a newly designed nickel thiaporphyrin complex [(STTP)NiC1; 1] catalyst. The copolymerization of cyclohexene oxide in the presence of 1 in THF at 40°C under 50 arm of CO2 selectively produced poly(cyclohexene carbonate) (PCHC). The dependence of this polymerization system on solvent, temperature, and CO2 pressure was examined. Furthermore, a series of Lewis bases or quaternary salts were added as a cocatalyst, revealing that the alternating manner of PCHC was definitively improved by using triphenylphosphine (Ph3P). The dependence of the polymerization system on the [1]/[Ph3P] ratio was further examined. [ABSTRACT FROM AUTHOR]

Polyurethane foam (PUF)/silica aerogel composites were successfully prepared as a heat insulating material by the supercritical carbon dioxide drying of PUTs filled with silica aerogels. PUF/silica aerogel composites were flexible and their thermal conductivities were as low as for the silica aerogel. The durability of PUF/silica aerogel composites was improved by using hydrophobic silica aerogel. PUF/hydrophobic silica aerogel composites were aged at 70°C and 95% RH. PUF/hydrophilic silica aerogel composite easily adsorbed water. Simultaneously, the volume shrank and the thermal conductivity of the composite drastically increased. On the other hand, PUF/hydrophobic silica aerogel composite was stable even at high temperature and in humidity conditions. After 10 weeks, the thermal conductivity of the composite hardly increased. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes (SPEs) have been proposed as solid-state alternatives to liquid electrolytes in electrochemical applications such as all- polymer Li batteries. However, these suffer from low ionic conductivity in the solid state compared with common liquid, gel and ceramic electrolytes. In this study, the preparation of SPEs using an alternative copolymer obtained from CO2 with an epoxide monomer instead of polyether was proposed synthesized and evaluated as a novel polymer candidate for SPEs. We used four types of polycarbonates (PCs) possessing different alkyl side groups; the SPE samples were prepared by the addition of 20-80 mol% LiTFSI. In all PC-based electrolytes, the glass transition temperature linearly decreased and the ionic conductivity increased with increasing LiTFSI concentration. Furthermore, longer alkyl side chains in PC decreased the conductivity, because the alkyl groups prevented LiTFSI dissociation. [ABSTRACT FROM AUTHOR]

Crystallization behaviors of polymer blends are reviewed. The crystallization of polymers is delayed in polymer blends by exclusion of non-crystalline components from the crystal growth front and crystals grow nonlinearly with crystallization time. Various crystalline morphologies are obtained by controlling the degree of exclusion in polymer/polymer, polymer/oligomer and polymer/carbon dioxide systems. On the other hand, the crystallization rate of polypropylene and poly(l-butene) was found to be drastically accelerated by blending the polyolefln with cyclodextrin inclusion complexes. In the blends with a two-phase region below the melting temperature, characteristic crystallization behavior occurs by competitive progress of phase separation and crystallization. Crystallization of polycarbonate was induced by the up-hill diffusion of the liquid-liquid phase separation via spinodal decomposition and connected spherulites were developed, for instance. [ABSTRACT FROM AUTHOR]

Nanoparticles of conductive polypyrrole (PPy) and its derivatives such as 3-heptylpyrrole (HPy) were successfully synthesized in a homogeneous supercritical carbon dioxide (scCO2). The homogeneous supercritical state was confirmed by observations of the phase behavior of the system through a high-pressure cell with a viewing window. Therefore, it became possible to synthesize their nanoparticles without the use of an organic solvent. The size of nanoparticles in the system decreased with more addition of CO2. This result suggested that the density of CO2 plays an important role in the control of the particle size. [ABSTRACT FROM AUTHOR]

Outstanding controlled-release materials were developed using statistical random copolymers of L-lactide (L-LA) with ε-caprolactone (CL) using Sn(oct)2 as a catalyst at 150°C for 24 h without solvent. Preparation of novel controlled-release materials was carried out using useful organic compounds with low boiling points and synthetic random copolymers composed of L-LA and CL as base materials under supercritical carbon dioxide (scCO2). Low-boiling-point compounds such as d-limonene, hinokitiol, and trans-2-hexenal were used. In impregnation experiments using scCO2, the amounts of low-boiling-point compounds increased with increasing L-LA content. When enzymatic degradation of poly(L-LA-ran-CL) was performed using lipase PS, copolymers with higher CL contents were degraded more rapidly than copolymers with higher L-LA content. On the other hand, enzymatic degradation of copolymers occurred to a higher degree with increasing L-LA content in enzymatic degradation by proteinase K. In a controlled-release experiment with poly(L-LA-ran-CL) ( = 73/27), after 400 h of degradation by proteinase K, the remaining weight of the copolymer pellet was 6%, and the amount of d-limonene remaining in the pellet was 15%. [ABSTRACT FROM AUTHOR]

Oxidative polymerization of 2,6-dimethylphenol (2,6-DMP) is a convenient method to prepare poly(2,6-dimethyl-1,4-phenyleneoxide) (PPO), an important plastic in engineering. The polymerization of 2,6-DMP is carried out in organic solvents under oxygen; thus, a solvent-recovery system and an anti-explosive reactor are required for the industrial application. The use of scCO2 instead of organic solvents is expected to make the polymerization of 2,6-DMP safer and environmentally more benign. We have studied the oxidative polymerization of 2,6-DMP in scCO2. In this report, we have applied the 'double-step polymerization' method in scCO2 to synthesize PPO with better polymer properties, i.e., higher average molecular weight (Mw) and narrower molecular weight distribution (Mw/Mn). In the first step, a prepolymer with a narrow molecular weight distribution (Mw/Mn = 1.4) was synthesized under a homogeneous-phase condition. The prepolymer was purified and dried to remove water. In the second step, the prepolymer was further polymerized to increase the molecular weight. The second-step polymerization was performed at 40°C and 20 MPa. The Mw was increased from 4.9 × 103 to 9.0 × 103, keeping the narrow molecular weight distribution (Mw/Mn = 1.4). We further optimized the polymerization condition in the second step to obtain higher molecular weight. The Mw was increased to 3.4 × 104 (Mw/Mm=2.3) at 80°C and 15 MPa in the presence of CuBr (0.0004 mol) and pyridine (0.019 mol). [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes (SPEs) such as poly (ethylene oxide)-metal salt complexes have been proposed as solid-state alternatives to liquid electrolytes in electrochemical device applications such as all-polymer lithium batteries. However, SPEs suffer from relatively low ionic conductivity in the solid state compared with most liquid, gel and ceramic electrolytes. For increase in the migration of ions, we have been focusing on compressed carbon dioxide, especially supercritical carbon dioxide (scCO2) as a unique solvent for SPEs. The treatment of SPEs with scCO2 gave rise to a large increase in the conductivity of polyether-Li salt complexes. Moreover, we measured the conductivity directly in pressurized CO2. The SPEs revealed a significant increase in the conductivity in the high-pressure conditions. It was found that CO2 plays an important role for adsorption, plasticization for polymers and dissociation of aggregated ions. CO2 is able to cause a dramatic decrease in the Tg of SPEs leading to an increase in the conductivity in solid state. [ABSTRACT FROM AUTHOR]

Novel poly(vinyl ether)s with tetraethylene glycol and methacrylate side groups [poly(TetraEGMVE-VEEM)] were synthesized by the copolymerization of TetraEGMVE with VEEM. The free-standing membranes of poly(TetraEGMVE-VEEM)s were prepared by thermal crosslinking between the methacrylate units. Membranes of poly(TetraEGMVE-VEEM) with 2:1 composition ratio showed high CO2 permeability and CO2/N2 selectivity, whose PCO2 and PCO2/PN2 were 250 barrer and 52, respectively. The PCO2 of membranes of poly(TetraEGMVE-VEEM) with 4:1 composition ratio was 320 barrer, which is larger than that with 2:1 composition ratio. This difference is caused by the number of crosslinking points in the polymer matrix. The CO2 permeability of poly(TetraEGMVE-VEEM) is higher than that of poly(vinyl ether) having diethylene glycols as a side chain. This high permeability originates from the high diffusivity of CO2 in the membranes. [ABSTRACT FROM AUTHOR]

Gas permeability of ionene polymers (PTIs) containing poly(tetrahydrofuran) [PTHF] soft-segment blocks (the molecular weight of PTHF block: 1100 and 2300) and viologen hard ionic segments (counter anion: Cl-, Br-, and I-) were investigated. The gas permeability coefficients of carbon dioxide (PCO2) and the CO2 and N2 separation factor (PCO2/PN2) of PTI having the 2300-PTHF block molecular weight and Cl- counter anion were 201 barrer and 30, respectively, indicating that PTI is a good candidate for CO2 separation membrane polymer. [ABSTRACT FROM AUTHOR]