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1

Formulation of lignin phenol formaldehyde resins as a wood adhesive  

International Nuclear Information System (INIS)

This work describes the potential of reducing phenol with lignin in phenol formaldehyde resin formulation. The physical and chemical properties between lignin phenol formaldehyde resin (LPF) and commercial phenol formaldehyde resin (CPF) were compared. Phenol had been replaced by lignin [that was extracted from black liquor of oil palm empty fruit bunch (EFB)] in synthesizing resin with a ratio lignin to phenol 1:1. The IR spectra showed that there were similarities in functional groups between LPF resin and CPF resin. The comparison of physical strength properties via tensile strength test between LPF resin and CPF resin showed that the newly formulated resin has higher bonding strength compared to commercial resin. Kinematics viscosity test showed that LPF resin has lower kinematics viscosity compared to CPF resin in 21 days storage time. SEM images for both resin showed similarities in the effect of resin penetration into woods vessel existed. (author)

2

RELATION BETWEEN MECHANICAL PROPERTIES AND PYROLYSIS TEMPERATURE OF PHENOL FORMALDEHYDE RESIN FOR GAS SEPARATION MEMBRANES  

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Full Text Available The aim of this paper has been to characterize the relation between the pyrolysis temperature of phenol-formaldehyde resin, the development of a porous structure, and the mechanical properties for the application of semipermeable membranes for gas separation. No previous study has dealt with this problem in its entirety. Phenol-formaldehyde resin showed an increasing trend toward micropore porosity in the temperature range from 500 till 1000°C, together with closure of mesopores and macropores. Samples cured and pyrolyzed at 1000°C pronounced hysteresis of desorption branch. The ultimate bending strength was measured using a four-point arrangement that is more suitable for measuring of brittle materials. The chevron notch technique was used for determination the fracture toughness. The results for mechanical properties indicated that phenol-formaldehyde resin pyrolyzates behaved similarly to ceramic materials. The data obtained for the material can be used for calculating the technical design of gas separation membranes.

MONIKA ŠUPOVÁ

2012-03-01

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Thermal and mechanical behavior of modified phenol formaldehyde resin  

International Nuclear Information System (INIS)

Polyamide is a modifier which introduces flexibility and toughness to phenolic foam by non reactive approach. Phenol formaldehyde resin was physically modified by the addition of polyamide in different percentages ranging from 0.05% to 0.2% which introduced toughness to modified resole. The resultant polymers were characterized by thermal and mechanical analysis using Thermogravimetric Analyzer (TGA), Instron machine and Dynamic Mechanical Analyzer (DMA). (author)

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Electron beam curable phenol-formaldehyde resin  

International Nuclear Information System (INIS)

The novolac type phenolic resins were synthesized and electron beam curing was carried out to the prepolymer obtained by the reaction of the phenolic resin and glycidyl meth acrylate in the presence of triethylbenzyl ammonium chloride. When the prepolymer and its mixtures with monomers were irradiated using electron beams at a dose rate of 3 Mrad/sec, the curing were completed at a dose 2.5 and 3 Mrad respectively. The effects of oxygen and that of hydroxyl group in the prepolymer on electron beam curing were also examined. (author)

5

Process for preparing phenolic formaldehyde resole resin products derived from fractionated fast-pyrolysis oils  

Science.gov (United States)

A process for preparing phenol-formaldehyde resole resins and adhesive compositions in which portions of the phenol normally contained in said resins are replaced by a phenol/neutral fractions extract obtained from fractionating fast-pyrolysis oils.

Chum, Helena L. (Arvada, CO); Kreibich, Roland E. (Auburn, WA)

1992-01-01

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Studies of the incorporation of simulated spent ion-exchange resins into phenol-formaldehyde polymer  

International Nuclear Information System (INIS)

Simulated spent ion-exchange resin, labelled and inactive samples, have been immobilized by transforming them into homogeneous monolithic forms. Immobilization was achieved by incorporating the ion-exchange resin into an inert polymer matrix (namely, phenol-formaldehyde polymer) aimed at lowering as much as possible the release of radionuclides to the environment. The suitability and range of applicability of phenol-formaldehyde to immobilize various types of resins having different levels of activity were determined by studying the homogeneity, mechanical, thermal and chemical properties of the final solid products. Factors such as water content and mesh size of the incororated resins, type of leaching solution, coating and irradiation effects of the final products have also been investigated. (Auth.)

7

HPLC Characterization of Phenol-Formaldehyde Resole Resin Used in Fabrication of Shuttle Booster Nozzles  

Science.gov (United States)

A reverse phase High Performance Liquid Chromatographic method was developed to rapidly fingerprint a phenol-formaldehyde resole resin similar to Durite(R) SC-1008. This resin is used in the fabrication of carbon-carbon composite materials from which Space Shuttle Solid Rocket Booster nozzles are manufactured. A knowledge of resin chemistry is essential to successful composite processing and performance. The results indicate that a high quality separation of over 35 peaks in 25 minutes were obtained using a 15 cm Phenomenex LUNA C8 bonded reverse phase column, a three-way water-acetonitrile-methanol nonlinear gradient, and LTV detection at 280 nm.

Young, Philip R.

1999-01-01

8

Study on the pyrolysis of phenol-formaldehyde (PF) resin and modified PF resin  

International Nuclear Information System (INIS)

The pyrolysis of pure phenol-formaldehyde (PF) resin and boron carbide (B4C) modified PF resin was investigated by using thermogravimetry (TG) and pyrolysis gas-chromatography-mass-spectrometry (PY-GC/MS). Scanning electron microscope (SEM) and Fourier transform infrared (FT-IR) spectroscopy were also employed to investigate the micro-structural evolution. It was shown from the TG analysis that the char residues of pure PF resin were 62.9 and 60.5% after being pyrolyzed at 700 and 1000 oC, respectively. The degradation and failure of the resin matrix were mainly resulted from the release of volatiles. The phenol and its methyl derivates took a large proportion in the amount of volatiles. In comparison with the pure PF resin, the char residues of B4C modified PF resin were obviously higher, with the values of 71.9 and 68.4% at 700 and 1000 oC, respectively. Due to the oxidation-reduction reactions between B4C additive and oxygen-containing volatiles including CO and H2O, partial carbon and oxygen elements in the volatiles remained in the resin matrix in the forms of amorphous carbon and B2O3, respectively. The results of SEM and FT-IR characterization demonstrated the occurrence of the modification, and the amorphous carbon existed in the form of reticular substance. In addition, the amount of the released phenol and its methyl derivates was also decreased drastically due to the for also decreased drastically due to the formation of borate.

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CHARACTERIZATION OF ALKALINE LIGNINS FOR USE IN PHENOL-FORMALDEHYDE AND EPOXY RESINS  

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Full Text Available Besides polyurethanes and polyesters, phenolic and epoxy resins are the most prominent applications for technical lignins in thermosetting materials. To evaluate the potential application of lignin raw materials in phenol formaldehyde and epoxy resins, three types of alkaline lignins were characterized in terms of their structures and thermal properties. The lignin samples analyzed were kraft lignin (LIG-1, soda–rice straw lignin (LIG-2, and soda-wheat straw lignin (LIG-3. FTIR and 1H-NMR methods were used to determine their structure. Gel permeation chromatography (GPC was used to determine the molecular weight distribution (MWD. Differential scanning calorimetry (DSC was used to measure the glass transition temperature (Tg, and thermogravimetric analysis (TGA to determine the thermal stability of lignin samples. Results showed that kraft lignin (LIG-1 has moderate hydroxyl-group content, is rich in G-type units, and has good thermal stability. These properties make it more suitable for direct use in phenol formaldehyde resins, and it is therefore a good raw material for this purpose. The alkaline soda-rice straw lignin (LIG-2 with a high hydroxyl-group content and excellent thermal stability is most suited to preparing lignin-based epoxy resins.

Nour Eddine El Mansouri

2011-05-01

10

Preconcentration of Cu (II) from seawater using a novel and stable phenol-formaldehyde resin.  

Science.gov (United States)

Preconcentration of Cu (II) from seawater using a novel phenol-formaldehyde (P-F) resin was investigated. 1,2-dihydroxybenzene-4-azo-3-hydroxybenzene-formaldehyde resin (DAHBF) was prepared by condensing 1,2-dihydroxybenzene-4-azo-3-hydroxybenzene with formaldehyde (1:2 mole ratio) in the presence of oxalic acid as catalyst. Polychelates were obtained when the DAHBF was treated with the aqueous solution of Cu (II) ions. The polymeric resin and polymer-metal complexes were characterized with thermal analysis and spectral studies. The IR spectra of polychelates suggest that the metal was coordinated through the oxygen atoms of the dihydroxybenzene moiety. The TGA data revealed the thermal stability of the resin and the polychelates. X-ray diffraction study revealed the incorporation of the metal ion significantly enhanced the degree of crystallinity. The sorption properties of the chelate forming resin towards divalent metal ion [Cu(II)] was studied as a function of pH, preconcentration time, metal concentration, amount of resin, aqueous phase volume and presence of electrolyte. This procedure was validated for recovery of copper from seawater samples. The method has adequate accuracy and it can be used for determination of copper in sea water samples. PMID:20371945

Manivannan, D; Starvin, Maria; Biju, V M

2010-01-01

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A Microfluidic Chip Using Phenol Formaldehyde Resin for Uniform-Sized Polycaprolactone and Chitosan Microparticle Generation  

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Full Text Available This study develops a new solvent-compatible microfluidic chip based on phenol formaldehyde resin (PFR. In addition to its solvent-resistant characteristics, this microfluidic platform also features easy fabrication, organization, decomposition for cleaning, and reusability compared with conventional chips. Both solvent-dependent (e.g., polycaprolactone and nonsolvent-dependent (e.g., chitosan microparticles were successfully prepared. The size of emulsion droplets could be easily adjusted by tuning the flow rates of the dispersed/continuous phases. After evaporation, polycaprolactone microparticles ranging from 29.3 to 62.7 ?m and chitosan microparticles ranging from 215.5 to 566.3 ?m were obtained with a 10% relative standard deviation in size. The proposed PFR microfluidic platform has the advantages of active control of the particle size with a narrow size distribution as well as a simple and low cost process with a high throughput.

Wan-Chen Hsieh

2013-06-01

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Effect of nanosilica on characteristics of carbonizates of phenol-formaldehyde resin - Fe(acac)3  

Science.gov (United States)

A series of carbon-iron-silica (CIS) composites (carbonizates) were prepared by carbonization of phenol-formaldehyde resin - Fe(III) acetylacetonate mixtures with addition of different amount of nanosilica A380 and compared with a composite prepared without silica (CFe composite). The characteristics of the composites differ because two type iron silicates were formed at a surface of silica nanoparticles and affected structure of carbon-iron phases. The textural characteristics of the CIS composites show a decrease in meso- and macroporosity and an increase in nanoporosity because new nanoparticles are formed in voids between silica nanoparticles. The CFe particles, including graphite-like structures, metallic iron nanoparticles and Fe3C, are larger than the CIS particles, which also include iron silicates, amorphous and crystalline silica. The presence of metallic ?-Fe nanoparticles can provide the magnetic properties of the composites.

Gun'ko, V. M.; Bogatyrov, V. M.; Oranska, O. I.; Galaburda, M. V.; Polshin, E. V.; Urubkov, I. V.; Leboda, R.; Skubiszewska-Zi?ba, J.; Charmas, B.

2013-01-01

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Effect of nano BaCO3 on pyrolytic reaction of phenol-formaldehyde resin  

Science.gov (United States)

Phenol-formaldehyde resin is used as the most adhesive to produce waterproof plant-based composite. However, this product contains phenol and formaldehyde which can be easily released to pollute air and water. Based on the single-factor method, the effect of nano BaCO3 on situabtion of pyrolytic reaction of PF resin was studied by Py-GC/MS. There were components including carbon dioxide, D,.alpha.-tocopherol, 1,3-bis(trimethylsilyl) benzene, phenol from PF resin in 590(see manuscript) He gas. However, the 17 compounds including phenol, 2-methyl-, phenol, carbon dioxide, p-xylene, toluene, phenol, 2-ethyl-, phenol, 2,3-dimethyl-, benzene, 1,2,3-trimethyl-, etc were identified by Py-GC/MS after PF/BaCO3 composite was pyrolyzed in 590(see manuscript) He gas, and phenol and phenol derivants were found in the compounds. The result showed that nano BaCO3 could effectively delay the pyrolysis of PF resin.

Zhang, Xu; Ma, Qing-zhi; Zhang, Zhong-feng; Peng, Wan-xi; Zhang, Ming-long

2009-07-01

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Study on preparation and properties of phenol-formaldehyde-chinese fir liquefaction copolymer resin  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english A new zero-waste and zero-pollution composite adhesive labeled Chinese fir-based adhesive for exterior plywood was synthesized by blending alkaline Chinese fir (Cunninghamia lanceolata) liquid with a small amount of phenol-formaldehyde (PF). The free phenol and free formaldehyde content of the Chine [...] se fir-based adhesive were sharply decreased compared to normal PF resin by more than 50%. The synthetic adhesive show with excellent water resistance and environmental friendliness, which had a 28h boil-dry-boil wet bonding strength of 1,73MPa according to standard JIS K6806-2003 and a formaldehyde emission of 0,045mg/L according to standard JIS A1460-2003. The structural properties and their thermal properties of cured adhesives were evaluated using Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC). The FT-IR analysis confirmed the expected chemical structure as the Chinese fir liquid reacted with formaldehyde and phenol which occurred at the wavenumbers of 1733, 1698, 1652cm-1 and 1077, 1048 cm-1. Although the DSC results indicated that the Chinese fir-based adhesive's curing need higher temperature than the control PF resin, the higher curing temperature hardly cripple the availability of Chinese fir-based resin in the plywood production.

Ruihang, Lin; Jin, Sun; Chao, Yue; Xiaobo, Wang; Dengyu, Tu; Zhenzhong, Gao.

2014-05-01

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Arsenate sorption by hydrous ferric oxide incorporated onto granular activated carbon with phenol formaldehyde resins coating.  

Science.gov (United States)

A simple and effective method was developed using phenol formaldehyde (PF) resins to immobilize hydrous ferric oxide (HFO) onto granular activated carbon (GAC). The resulting sorbent possesses advantages for both the ferric oxide and the GAC, such as a great As-affinity of ferric oxide, large surface area of GAC, and enhanced physical strength. The studies showed that within one hour this sorbent was able to remove 85% of As(V) from water containing an initial As(V) concentration of 1.74 mg l(-1). The As(V) adsorption onto the sorbent was found to follow a pseudo-second order kinetics model. The adsorption isotherms were interpreted in terms of the Langmuir and Freundlich models. The equilibrium data fitted very well to both models. Column tests showed that this sorbent was able to achieve residual concentrations of As(V) in a range of 0.1-2.0 microg l(-1) while continuously treating about 180 bed volume (BV, 130 ml-BV) of arsenate water with an initial As(V) concentration of 1886 microg l(-1) at a filtration rate of 13.5 ml min(-1), i.e., an empty bed contact time (EBCT) of 9.6 min and a gram sorbent contact time (GSCT) of 0.15 min. After passing 635 BV of arsenate water, the exhausted sorbent was then tested by the Toxicity Characteristic Leaching Procedure (TCLP, US EPA Method 1311) test, and classified as non-hazardous for disposal. Hence, this HFO-PF-coated GAC has the capability to remove As(V) from industrial wastewater containing As(V) levels of about 2 mg l(-1). PMID:18619145

Zhuang, J M; Hobenshield, E; Walsh, T

2008-04-01

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Synthesis of carbon-encapsulated iron carbide/iron nanoparticles from phenolic-formaldehyde resin and ferric nitrate  

International Nuclear Information System (INIS)

Carbon-encapsulated iron carbide/iron nanoparticles have been synthesized on a large scale by the heat treatment of thermal plastic phenolic-formaldehyde resin with the aid of ferric nitrate. The effects of heating temperature on the morphologies and structures of carbonized products were investigated using transmission electron microscope, high-resolution transmission electron microscope and X-ray diffraction measurements. The products with diameter distribution of 20-100 nm consisted mainly of spheroidal nanoparticles separated by hollow onion-like carbon nanoparticles.

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Microporous phenol-formaldehyde resin-based adsorbents for pre-combustion CO{sub 2} capture  

Energy Technology Data Exchange (ETDEWEB)

Different types of phenolic resins were used as precursor materials to prepare adsorbents for the separation of CO{sub 2} in pre-combustion processes. In order to obtain highly microporous carbons with suitable characteristics for the separation of CO{sub 2} and H{sub 2} under high pressure conditions, phenol-formaldehyde resins were synthesised under different conditions. Resol resins were obtained by using an alkaline environment while Novolac resins were synthesised in the presence of acid catalysts. In addition, two organic additives, ethylene glycol (E) and polyethylene glycol (PE) were included in the synthesis. The phenolic resins thus prepared were carbonised at different temperatures and then physically activated with CO{sub 2}. The carbons produced were characterised in terms of texture, chemical composition and surface chemistry. Maximum CO{sub 2} adsorption capacities at atmospheric pressure were determined in a thermogravimetric analyser. Values of up to 10.8 wt.% were achieved. The high-pressure adsorption of CO{sub 2} at room temperature was determined in a high-pressure magnetic suspension balance. The carbons tested showed enhanced CO{sub 2} uptakes at high pressures (up to 44.7 wt.% at 25 bar). In addition, it was confirmed that capture capacities depend highly on the microporosity of the samples, the narrow micropores (pore widths of less than 0.7 nm) being the most active in CO{sub 2} adsorption at atmospheric pressure. The results presented in this work suggest that phenol-formaldehyde resin-derived activated carbons, particularly those prepared with the addition of ethylene glycol, show great potential as adsorbents for pre-combustion CO{sub 2} capture. 39 refs., 6 figs., 4 tabs.

C.F. Martin; M.G. Plaza; S. Garcia; J.J. Pis; F. Rubiera; C. Pevida [Instituto Nacional del Carbon (INCAR), Oviedo (Spain)

2011-05-15

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Study on the structural evolution of modified phenol-formaldehyde resin adhesive for the high-temperature bonding of graphite  

International Nuclear Information System (INIS)

A novel adhesive for carbon materials composed of phenol-formaldehyde resin, boron carbide and fumed silica, was prepared. The adhesive property of graphite joints bonded by the above adhesive treated at high-temperatures was tested. Results showed that the adhesive was found to have outstanding high-temperature bonding properties for graphite. The adhesive structure was dense and uniform even after the graphite joints were heat-treated at 1500 deg. C. Bonding strength was 17.1 MPa. The evolution of adhesive structure was investigated. The results indicated that the addition of the secondary additive, fumed silica, improved the bonding performance greatly. Borosilicate phase with better stability was formed during the heat-treatment process, and the volume shrinkage was restrained effectively, which was responsible for the satisfactory high-temperature bonding performance of graphite

19

One-pot synthesis of biocompatible Te-phenol formaldehyde resin core-shell nanowires with uniform size and unique fluorescent properties by a synergized soft-hard template process  

International Nuclear Information System (INIS)

One-pot hydrothermal process has been developed to synthesize uniform Te-phenol formaldehyde resin core-shell nanowires with unique fluorescent properties. A synergistic soft-hard template mechanism has been proposed to explain the formation of the core-shell nanowires. The Te-phenol formaldehyde resin core-shell nanowires display unique fluorescent properties, which give strong luminescent emission in the blue-violet and green regions with excitation wavelengths of 270 nm and 402 nm, respectively.

20

Expansive failure reactions and their prevention in the encapsulation of phenol formaldehyde type ion exchange resins in cement based systems  

International Nuclear Information System (INIS)

Lewatit DN is a phenol formaldehyde based ion exchange resin used to remove radioactive caesium from liquid waste streams such as fuel cooling ponds and effluents. This paper presents the results of a study of the encapsulation of the bead form of the resin in cement with particular reference to the mechanisms of its interaction with the encapsulant. When incorporated in pure ordinary Portland cement (OPC) at loadings in excess of 15 wt% an unstable product results due to expansion of the system and at higher waste loadings failure results after only a few days. The resin beads swell on contact with the alkaline pH environment of the cement but this occurs too rapidly to be the cause of the expansive failure reaction. Increased production of ettringite can also be ruled out as the sulphate concentrations in the resin are too low. Blending the OPC with blast furnace slag (BFS) gives a satisfactory product up to 25 wt% loading and addition of sodium hydroxide to the mix water enables loading of up to 36 wt% to be employed. Evidence from differential scanning calorimetry. X-ray diffraction and scanning electron microscopy all indicate the cause of the expansive reaction to be the formation of crystals of calcium salts around and within the resin beads. Calcium hydroxide, calcium oxalate and calcium carbonate were observed. Addition of BFS and sodium hydroxide prevent the formation of these salts by removal of calcium hydroxide from the system in other reactions. (author)om the system in other reactions. (author)

21

Assessment of the chemical changes during storage of phenol-formaldehyde resins pyrolysis gas chromatography mass spectrometry, inverse gas chromatography and Fourier transform infra red methods.  

Science.gov (United States)

The chemical changes occurring in the phenol-formaldehyde resins (resol and novolac type) during their storage were investigated. In this paper the FT-IR, py-GCMS and inverse gas chromatography methods were applied for assessment of the changes occurring during storage of the phenolic resins. We have found that during storage some examined resins occurred partial curing. The results from all techniques applied are consistent. Py-GCMS is useful technique for screening the storage processes but IGC seems to be most sensitive one. PMID:25092596

Strzemiecka, B; Voelkel, A; Zi?ba-Palus, J; Lachowicz, T

2014-09-12

22

Adhesion properties of styrene-butadiene rubber (SBR/Standard Malaysian Rubber (SMR L-based adhesives in the presence of phenol formaldehyde resin  

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Full Text Available The adhesion properties, i. e. viscosity, tack and peel strength of styrene-butadiene rubber (SBR/Standard Malaysian Rubber (SMR L-based pressure-sensitive adhesive was studied using phenol formaldehyde resin as the tackifying resin. Toluene was used as the solvent throughout the experiment. SBR composition in SBR/SMR L blend used was 0, 20, 40, 60, 80, 100%. Three different resin loadings, i. e. 40, 80 and 120 parts per hundred parts of rubber (phr were used in the adhesive formulation. The viscosity of adhesive was determined by a HAAKE Rotary Viscometer whereas loop tack and peel strength of paper/polyethylene terephthalate (PET film were measured using a Lloyd Adhesion Tester operating at 30 cm/min. Results indicate that the viscosity of adhesive decreases with increasing % SBR whereas loop tack passes through a maximum value at 20% SBR for all resin loadings. Except for the control sample (without resin, the peel strength shows a maximum value at 60% SBR for the three modes of peel tests. For a fixed % SBR, adhesive sample containing 40 phr phenol formaldehyde resin always exhibits the highest loop tack and peel strength, an observation which is associated to the optimum wettability of adhesive on the substrate.

2007-10-01

23

Zinc isotope separation by phenol formaldehyde type 15-crown-5 resin in organic solvents  

International Nuclear Information System (INIS)

Zinc adsorption and isotope separation by newly synthesized benzo-15-crown-5 resin was evaluated using various solvents. This resin was synthesized in the pores of silica beads for chromatography use. Larger adsorption of zinc was obtained in the case of acetic acid derivatives than in protic solvent such as water and alcohol by the batch treatment. The displacement chromatography was conducted to study zinc isotope separation. The isotope separation coefficient ?=0.32x10-3, 0.69x10-3 and HETP=0.2268, 0.3968 cm were determined for isotopic pair of 68Zn/64Zn at 25degC by five meters migration experiment using methyl isobutyl ketone and acetic acid, respectively. The improvement of enrichment ratio is very small between 1 and 5 m migration. Hydrogen chloride and/or water obviously reduce zinc adsorption to this resin. (author)

24

Tunable mesoporous bilayer photonic resins with chiral nematic structures and actuator properties.  

Science.gov (United States)

Chiral nematic structures with different helical pitch from layer to layer are embedded into phenol-formaldehyde bilayer resin composite films using cellulose nanocrystals (CNCs) as templates. Selective removal of CNCs results in mesoporous resins with different pore size and helical pitch between the layers. Consequently, these materials exhibit photonic properties by selectively reflecting lights of two different wavelengths and concomitant actuation properties. PMID:24446312

Khan, Mostofa K; Hamad, Wadood Y; Maclachlan, Mark J

2014-04-16

25

Production of plywood panels from Pinus taeda using veneers of differing densities and phenol-formaldehyde resin with high and low molecular weights  

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Full Text Available This study aimed to evaluate the bonding quality of plywood panels from Pinus taeda using low and high molecular weight phenol-formaldehyde resin and veneers from three different density classes. The experiment consisted of six treatments, each of which produced three panels (replicates. Tests were conducted to evaluate glue line strength to shear stress after two boiling cycles and after 24 hours of cold water immersion. Also determined was the percentage of defects in wood samples. Results indicated that the density classes being assessed differed statistically. However, no significant difference was found between panels produced with high and panels produced with low molecular weight resin as to the mean values of glue line strength, whether subjecting them to two boiling cycles or after 24 hours of cold water immersion. Interactions between different density classes and adhesive formulations were found not significant either. Low molecular weight resin (BPM and panels produced with higher density veneers were found to have better behavior, regarding both bonding strength and percentage of defects. It was concluded that the bonding quality of plywood panels from Pinus taeda was satisfactory after using different densities of veneer and also high and low molecular weight phenolic resins. All treatments were found to comply with minimum requirements established in European standard EN 314-1/1993, which addresses bonding quality of plywood panels.

Graciela Ines Bolzon de Muniz

2013-06-01

26

Novel halogen-free flame retardant thermoset from a hybrid hexakis (methoxymethyl melamine/phosphorus-containing epoxy resin cured with phenol formaldehyde novolac  

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Full Text Available This paper describes the curing behaviours, thermal properties and flame-resistance of a novel halogen-free epoxy hybrid thermoset, prepared by the curing reaction of hexakis (methoxymethyl melamine (HMMM, a phosphorouscontaining epoxy resin (EPN-D with 9, 10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO group and phenol formaldehyde novolac (n-PF. The resultant thermosets showed high glass-transition temperatures (Tg, 123–147°C as determined by thermal mechanical analysis (TMA, excellent thermal stability with high 5 wt% decomposition temperatures (Td,5% ??308°C and high char yields (Yc ??39.4 wt% from the thermogravimetric analysis (TGA. All the cured EPND/ HMMM/n-PF hybrid resins achieved the UL 94 V-0 grade with high limited oxygen indices (LOI > 45.7. It is found that phosphorous and nitrogen elements in the cured EPN-D/HMMM/n-PF hybrid resins had a positive synergistic effect on the improvement of the flame retardancy.

2009-12-01

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Evidencia de la biodegradación de resinas fenólicas con hongos ligninolíticos por microscopía electrónica de barrido / Scanning electronic microscopy evidence of phenol-formaldehyde resins biodegradation with ligninolitic fungi  

Scientific Electronic Library Online (English)

Full Text Available Los polímeros sintéticos están generando problemas ambientales debido a que generalmente son resistentes a la degradación, sin embargo, investigaciones recientes se han enfocado en métodos biológicos para tratar estos residuos y el desarrollo de plásticos degradables. Los plásticos están clasificado [...] s en dos grandes tipos: termoplásticos y termoestables. Las resinas fenólicas están incluidas dentro de los termoestables, las cuales no pueden ser fundidas por lo tanto no son susceptibles al reciclado y causan un problema ambiental. A través de los estudios acerca de los hongos ligninolíticos se ha determinado que estos organismos producen enzimas extracelulares con alta inespecificidad química e intensa actividad oxidante, lo que les otorga una considerable capacidad para degradar diferentes compuestos orgánicos con estructura similar a la lignina. El objetivo de este trabajo fue demostrar, utilizando microscopía electrónica de barrido que los hongos ligninolíticos tienen la capacidad de degradar las resinas fenólicas. Los resultados demostraron que los hongos Bjerkandera adusta, Pleurotus ostreatus, Phanerochaete chrysosporium y Sporotrichum pulverulentum pueden degradar las resinas fenólicas. Abstract in english Synthetic polymers are growing environmental concern because they are generally nondegradable and recent research has been focused on the biological treatment of plastic wastes and the development of biodegradable plastics. Plastics are classified into two broad types: thermoplastics and thermosetti [...] ng plastics. Phenol-formaldehyde resins (PF resins) are included in the thermosetting plastic category. They are products that once formed cannot be soften, therefore the process for recycling cannot be applied and they cause an environmental problem. Through intensive study of white-rot fungi it has been determined that these organisms produce extracellular enzymes with very low substrate specificity and intense oxidative activity. This makes them suitable for degradation of many different compounds notably organopollutants with structural similarities to lignin. The object of this work was to demonstrate, using scanning electron microscopy, that ligninolitic fungi have the capacity to degrade PF resins. The results showed that the fungi Bjerkandera adusta, Pleurotus ostreatus, Phanerochaete chrysosporium and Sporotrichum pulverulentum can degrade the PF resins.

Graciela Ibeth, PONCE ANDRADE; Rafael, VÁZQUEZ DUHALT; Refugio, RODRÍGUEZ VÁZQUEZ; Iliana Ernestina, MEDINA RAMÍREZ; Juan Antonio, LOZANO ÁLVAREZ; Juan, JÁUREGUI RINCÓN.

2012-05-01

28

Ammonia-free, low-toxic press-materials with improved electroinsulating properties based on modified novolak phenol-formaldehyde resing Properties Based on Modified Novolak Phenol-formaldehyde Resin  

OpenAIRE

The technological and operational properties of press-materials based on novolak composition modified jointly by epoxydianic resin and polyvinylpyrrolidone depending upon filler nature and pressing conditions have been determined. The reactivity of obtained press-powders has been investigated depending upon filler type, as well as curing conditions of composites under which ammonia and formaldehyde are not emitted. It has been shown that developed press-materials have the same technologica...

Suberlyak, Oleh; Krasinskiy, Volodymyr; Sikora, Janusz; Krzyz?ak, Aneta

2012-01-01

29

In situ synthesis of N and Cu functionalized mesoporous FDU-14 resins and carbons for electrochemical hydrogen storage  

Energy Technology Data Exchange (ETDEWEB)

N and Cu cooperatively functionalized mesoporous resin and carbon materials with bicontinuous cubic structure (FDU-14) were obtained by a novel synthesis method. In this method, block copolymers were used as the templates as well as the precursors for the preparation of these modifying mesoporous materials. The CuC{sub 2}O{sub 4} in the channels of mesoporous FDU-14 resins was gotten by in situ oxidation of the templates in a catalytic redox system containing Cu{sup 2+}, Al{sup 3+}, NO{sub 3}{sup -}, PO{sub 4}{sup 3-}, SO{sub 4}{sup 2-} ions. Simultaneously, the phenol-formaldehyde resin frameworks were in situ functionalized by the amine group resulting from the reduction of NO{sub 3}{sup -}, leading to the formation of N and CuC{sub 2}O{sub 4} modified mesoporous FDU-14 resin materials. Its pyrolysis at the different temperatures resulted in the production of N and Cu cooperatively functionalized mesoporous FDU-14 resin and carbon materials. The structure and composition of these materials were characterized by the X-ray power diffraction, transmission electron microscopy, N{sub 2} adsorption-desorption analysis, X-ray photoelectron spectroscopy, infrared spectroscopy, thermogravimetry analysis, and inductive coupled plasma emission spectroscopy. The electrochemical measurement indicated that N and Cu cooperatively functionalized mesoporous FDU-14 carbon materials possessed the enhanced electrochemical hydrogen storage performance. (author)

Kong, AiGuo; Wang, WenJuan; Yang, Fan; Ding, HanMing; Shan, YongKui [Department of Chemistry, East China Normal University, ShangHai 200062 (China)

2010-07-15

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Adhesion characteristics of phenol formaldehyde pre-preg oil palm stem veneers  

OpenAIRE

The purpose of this study was to evaluate the adhesion properties of phenol formaldehyde-prepreg oil palm veneers that have potential for plywood manufacture. Phenol formaldehyde (PF) resin of three different molecular weights (i.e. 600 (low), 2,000 (medium), and 5,000 (commercial)) were used to pre-treat the veneers. The veneers were soaked in each type of PF resin for 20 seconds, pressed between two rollers, and pre-cured in an oven maintained at 103 ± 2 °C for 24 hours. The volume percen...

Nor Hafizah Ab. Wahab; Paridah Md. Tahir; Yeoh Beng Hoong; Zaidon Ashaari,; Nor Yuziah Mohd Yunus; Mohd Khairun Anwar Uyup; Mohd Hamami Shahri

2012-01-01

31

40 CFR 721.7220 - Polymer of substituted phenol, formaldehyde, epichlorohydrin, and disubstituted benzene.  

Science.gov (United States)

...2010-07-01 false Polymer of substituted phenol, formaldehyde, epichlorohydrin, and... § 721.7220 Polymer of substituted phenol, formaldehyde, epichlorohydrin, and...identified generically as polymer of substituted phenol, formaldehyde,...

2010-07-01

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Phenol-formaldehyde oligomers application for coatings production ?????????? ????????????????????? ?????????? ??? ???????????? ????????? ??????????  

Directory of Open Access Journals (Sweden)

Full Text Available The description developed by the authors of structures and technologies production safety coatings based on glass fiber and paper, modified phenol-formaldehyde oligomers, which are possessed high physicochemical properties, durability and chemical durability, is presented.????????? ???????? ????????????? ???????? ???????? ? ?????????? ????????? ???????-????????? ?????????? ?? ?????? ???????????????? ????????????????????? ??????????? ???????????? ? ??????, ?????????? ???????? ??????-??????????? ??????????, ?????????????? ? ?????????? ??????????.

Orlova Anzhela Manvelovna

2011-11-01

33

Adhesion characteristics of phenol formaldehyde pre-preg oil palm stem veneers  

Directory of Open Access Journals (Sweden)

Full Text Available The purpose of this study was to evaluate the adhesion properties of phenol formaldehyde-prepreg oil palm veneers that have potential for plywood manufacture. Phenol formaldehyde (PF resin of three different molecular weights (i.e. 600 (low, 2,000 (medium, and 5,000 (commercial were used to pre-treat the veneers. The veneers were soaked in each type of PF resin for 20 seconds, pressed between two rollers, and pre-cured in an oven maintained at 103 ± 2 °C for 24 hours. The volume percent gain (VPG, weight percent gain (WPG, pH, buffering capacity, and contact angle of the phenolic pre-preg veneers were determined. The bonding shear was also evaluated according to British Standard European Norm BS EN 314. The results show that veneers from both inner and outer layers treated with low molecular weight PF (LMwPF resin had significantly higher VPG and WPG compared to the other PF resins. The pH values of all of the veneers were slightly acidic (6.5 to 6.8 except for those that were treated with commercial molecular weight PF resin (7.8. A buffering capacity study revealed that untreated veneer had a greater resistance toward alkali, but was unstable under acidic conditions, while the phenolic pre-preg veneer behaved differently. This effect was more prominent as the molecular weight of the PF resin increased. An examination of the veneer surfaces demonstrated that phenolic treatment had increased the contact angle of the OPS veneer surfaces significantly. The bonding properties of plywood made from pre-preg palm veneers were found to be superior to those of commercial palm plywood.

Nor Hafizah Ab. Wahab

2012-11-01

34

Properties of Modified Phenol-Formaldehyde Adhesive for Plywood Panels Manufactured from High Moisture Content Veneer  

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Full Text Available This paper presents the results of laboratory investigations of bonding high moisture content (15 % birch veneers (Betula pubescens Ehrh. with the use of modifi ed phenol-formaldehyde (PF resin. Wheat starch, rye flour, resorcinol and phenol-resorcinol-formaldehyde resin were chosen as modifying agents. Dynamic viscosity, hydrogen ions concentration, solid content, curing time, pot life of developed adhesive compositions and shear strength of plywood samples were evaluated. ANOVA analysis has shown that type, mixture and content of modifying agents affect significantly the mechanical performance of plywood panels. The obtained results of shear strength values were above the standard requirements (1 N/mm2, and the properties of samples met the European standard EN 314-2 for gluing quality of class 3 and such plywood panels can be used in exterior conditions.

Pavlo Bekhta

2015-01-01

35

Synthesis of white light emitting mesoporous carbon-silica nanocomposite  

Science.gov (United States)

White light emitting mesoporous carbon-silica (MPCS) was synthesized by serially adding triblock copolymer (Pluronic, F127), ethanol (EtOH), tetraethoxysilane (TEOS), hydrochloric acid aqueous (HCl) and phenol-formaldehyde resin (resol) followed by the heat treatments of carbonization and oxidation. The PL intensity of MPCS showed a tendency to be strong with increasing of HCl concentration in >= 0.2 M. The pore size of MPCS that emits white light was 8 ~ 9 nm and the specific surface area was 320 ~ 418 m2 / g.

Sato, Koji; Ishikawa, Yukari; Matsumura, Akihiro; Ishii, Yosuke; Kawasaki, Shinji

2011-05-01

36

Production of plywood panels from Pinus taeda using veneers of differing densities and phenol-formaldehyde resin with high and low molecular weights / Produção de painéis compensados de Pinus taeda com lâminas de diferentes densidades e resina fenol-formaldeído com alto e baixo peso molecular  

Scientific Electronic Library Online (English)

Full Text Available Neste trabalho, objetivou-se avaliar a qualidade da colagem de painéis compensados de Pinus taeda, produzidos com resina fenol-formaldeido de alto e baixo peso molecular, e lâminas de três diferentes classes de densidades. O experimento foi organizado em seis tratamentos, e para cada tratamento fora [...] m produzidos três painéis (repetições). Os ensaios de resistência da linha de cola aos esforços de cisalhamento foram realizados após dois ciclos de fervura e após 24 horas de imersão em água fria. Determinou-se, também, a porcentagem de falhas na madeira. Os resultados indicaram que as classes de densidade são estatisticamente diferentes entre si. Entretanto, não houve diferença significativa entre os valores médios de resistência da linha de cola dos painéis produzidos com resina de alto e baixo peso molecular, tanto para os painéis submetidos aos dois ciclos de fervura, quanto para os submetidos ao ensaio após 24 horas em água fria. A interação entre as classes de densidade das lâminas e as formulações do adesivo, igualmente, não foi significativa. A resina de baixo peso molecular (BPM) e os compensados produzidos com as lâminas de maior densidade apresentou melhor comportamento, tanto para resistência quanto para a porcentagem de falha na madeira. Conclui-se que a qualidade de colagem dos painéis compensados de Pinus taeda produzidos com lâminas de densidades diferentes e com resinas fenólicas de alto e baixo peso molecular foi satisfatória. Todos os tratamentos atendem às exigências mínimas da norma européia EN 314-1/1993, que trata da qualidade da colagem de painéis compensados. Abstract in english This study aimed to evaluate the bonding quality of plywood panels from Pinus taeda using low and high molecular weight phenol-formaldehyde resin and veneers from three different density classes. The experiment consisted of six treatments, each of which produced three panels (replicates). Tests were [...] conducted to evaluate glue line strength to shear stress after two boiling cycles and after 24 hours of cold water immersion. Also determined was the percentage of defects in wood samples. Results indicated that the density classes being assessed differed statistically. However, no significant difference was found between panels produced with high and panels produced with low molecular weight resin as to the mean values of glue line strength, whether subjecting them to two boiling cycles or after 24 hours of cold water immersion. Interactions between different density classes and adhesive formulations were found not significant either. Low molecular weight resin (BPM) and panels produced with higher density veneers were found to have better behavior, regarding both bonding strength and percentage of defects. It was concluded that the bonding quality of plywood panels from Pinus taeda was satisfactory after using different densities of veneer and also high and low molecular weight phenolic resins. All treatments were found to comply with minimum requirements established in European standard EN 314-1/1993, which addresses bonding quality of plywood panels.

Graciela Ines Bolzon de, Muniz; Setsuo, Iwakiri; Lívia Cássia, Viana; Mário, Andrade; Cristiane, Weber; Vanessa Coelho, Almeida.

2013-06-01

37

Hierarchical activated mesoporous phenolic-resin-based carbons for supercapacitors.  

Science.gov (United States)

A series of hierarchical activated mesoporous carbons (AMCs) were prepared by the activation of highly ordered, body-centered cubic mesoporous phenolic-resin-based carbon with KOH. The effect of the KOH/carbon-weight ratio on the textural properties and capacitive performance of the AMCs was investigated in detail. An AMC prepared with a KOH/carbon-weight ratio of 6:1 possessed the largest specific surface area (1118?m(2) g(-1)), with retention of the ordered mesoporous structure, and exhibited the highest specific capacitance of 260?F?g(-1) at a current density of 0.1?A?g(-1) in 1?M H2 SO4 aqueous electrolyte. This material also showed excellent rate capability (163?F?g(-1) retained at 20?A?g(-1)) and good long-term electrochemical stability. This superior capacitive performance could be attributed to a large specific surface area and an optimized micro-mesopore structure, which not only increased the effective specific surface area for charge storage but also provided a favorable pathway for efficient ion transport. PMID:25100552

Wang, Zhao; Zhou, Min; Chen, Hao; Jiang, Jingui; Guan, Shiyou

2014-10-01

38

Investigation of radiation curing of phenol-formaldehyde oligomers  

International Nuclear Information System (INIS)

To obtain information on chemical transformations taking place under the effect of high energy radiation in phenol-formaldehyde oligomers, the process of their radiation curing has studied by infrared spectroscopy, EPR, and quantitative determination of gel-fraction. Curing of the samples has been performed by accelerated electrons with an energy 1.0-1.1 MeV. At a dose of 80 Mrad the yield of gel-fraction is 80 %. Introduction of sensibilizers activates the process; in this case the formation of the polymer net can be completed at doses as low as 20 Mrad. It has been shown that the mechanism of radiation curing differs insignificantly from that of thermochemical process

39

Effects of copper nitrate addition on the pore property and lithium storage performance of hierarchical porous carbon nanosheets from phenolic resin  

International Nuclear Information System (INIS)

Graphical abstract: - Abstract: Hierarchical porous carbon nanosheets (HPCS) were prepared by using thermoplastic phenolic formaldehyde resin as the carbon source and copper nitrate as the template precursor. The effects of Cu(NO3)2 loading content on the pore property and electrochemical performance of HPCS as anode material for lithium ion batteries were investigated. It was found that, with the addition of Cu(NO3)2, both the specific surface area and mesopore percentage increase. Correspondingly, the electrochemical performances of HPCS electrodes in terms of the specific capacity and rate performance improve for lithium ion batteries. The reasons were deduced and discussed from the view point of different pore size, especially the function of mesopores

40

Hydrothermal degradation of lignin: products analysis for phenol formaldehyde adhesive synthesis.  

Science.gov (United States)

Corncob lignin was treated with pressurized hot water in a cylindrical autoclave in current investigation. With the aim of investigating the effect of reaction temperature and retention time on the distribution of degradation products, the products were divided into five fractions including gas, volatile organic compounds, water-soluble oil, heavy oil, and solid residue. It was found that hydrothermal degradation of corncob lignin in pressurized hot water produced a large amount of phenolic compounds with lower molecular weight than the raw lignin. Some phenolic and benzene derivatives monomers such as vanillin, 2-methoxy-phenol, 2-ethyl-phenol, p-xylene, and 1, 3-dimethyl-benzene were also identified in the degradation products. The products were further analyzed by GC-MS, GPC, 2D-HSQC, and (31)P-NMR to investigate their suitability for partial incorporation into phenol formaldehyde adhesive as a substitution of phenol. The results indicated that the reaction temperature had more effect on the products distribution than the retention time. The optimal condition for heavy oil production appeared at 290 °C with retention time 0 min. The compounds of heavy oil had more active sites than the raw lignin, suggesting that the heavy oil obtained from hydrothermal degradation of lignin is a promising material for phenol formaldehyde adhesive synthesis. PMID:25109457

Yang, Sheng; Yuan, Tong-Qi; Li, Ming-Fei; Sun, Run-Cang

2015-01-01

41

Synthesis of sulphonated mesoporous phenolic resins and their application in esterification and asymmetric aldol reactions  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous phenolic resins were functionalized with sulphonic acid groups by four different types of sulphonation procedures: (i) direct sulphonation on the aromatic ring, (ii) alkyl sulphonation of the aromatic ring, and functionalizations of the phenolic hydroxyl surface by using an aryl silane, 2-(4-chlorosulphonylphenyl)ethyl trichlorosilane (iii) or a propyl silane, 3-mercaptopropyltrimethoxysilane (iv). The highest acidity loadings were obtained through direct sulphonation with fuming sulphuric acid (1.90 mmol H{sup +} g{sup ?1}) or chlorosulphonic acid (1.31 mmol H{sup +} g{sup ?1}) and these materials showed the highest conversion (97+ %) in Fischer esterification of acetic acid with propanol. However, the alkyl sulphonic groups, obtained through sulphonation procedure (ii) showed the highest stability in terms of maintenance of their acidity after use in consecutive catalytic runs or leaching treatments. This was demonstrated both through evaluation of the regenerated catalysts in a consecutive esterification run and during a leaching resistance test in aqueous medium. Moreover, the developed sulphonated mesoporous phenolic resins are presented as novel support for the non-covalent immobilization of an L-phenylalanine derived chiral diamine organocatalyst for asymmetric aldol reactions. The immobilization is established by an acid–base interaction between the sulphonic acid group and the amine function. The acidity and in particular the electronic withdrawing environment of the sulphonic acid groups influence enormously the catalytic performance of the non-covalent immobilized chiral diamine catalyst (aromatic > aliphatic). - Highlights: ? Different types of sulphonation procedures for mesoporous phenolic resins. ? Influence of acidity and electronic withdrawing environment. ? Novel support for non-covalent immobilization of chiral diamine catalyst. ? Catalytic performance in esterification and asymmetric aldol condensation. ? Demonstration of leaching resistance in aqueous medium.

Muylaert, Ilke [Department of Inorganic and Physical Chemistry, Ghent University, Center for Ordered Materials, Organometallics and Catalysis (COMOC), Krijgslaan 281-S3, 9000 Ghent (Belgium); Verberckmoes, An, E-mail: an.verberckmoes@hogent.be [Department of Inorganic and Physical Chemistry, Ghent University, Center for Ordered Materials, Organometallics and Catalysis (COMOC), Krijgslaan 281-S3, 9000 Ghent (Belgium); Associated Faculty of Applied Engineering Sciences, University College Ghent, Valentin Vaerwyckweg 1, 9000 Ghent (Belgium); Spileers, Jeremy [Associated Faculty of Applied Engineering Sciences, University College Ghent, Valentin Vaerwyckweg 1, 9000 Ghent (Belgium); Demuynck, Anneleen; Peng, Li; De Clippel, Filip; Sels, Bert [Katholieke Universiteit Leuven, Centre for Surface Chemistry and Catalysis (COK), Kasteelpark Arenberg 23, 3001 Heverlee (Belgium); Van Der Voort, Pascal, E-mail: pascal.vandervoort@ugent.be [Department of Inorganic and Physical Chemistry, Ghent University, Center for Ordered Materials, Organometallics and Catalysis (COMOC), Krijgslaan 281-S3, 9000 Ghent (Belgium)

2013-02-15

42

Synthesis of sulphonated mesoporous phenolic resins and their application in esterification and asymmetric aldol reactions  

International Nuclear Information System (INIS)

Mesoporous phenolic resins were functionalized with sulphonic acid groups by four different types of sulphonation procedures: (i) direct sulphonation on the aromatic ring, (ii) alkyl sulphonation of the aromatic ring, and functionalizations of the phenolic hydroxyl surface by using an aryl silane, 2-(4-chlorosulphonylphenyl)ethyl trichlorosilane (iii) or a propyl silane, 3-mercaptopropyltrimethoxysilane (iv). The highest acidity loadings were obtained through direct sulphonation with fuming sulphuric acid (1.90 mmol H+ g?1) or chlorosulphonic acid (1.31 mmol H+ g?1) and these materials showed the highest conversion (97+ %) in Fischer esterification of acetic acid with propanol. However, the alkyl sulphonic groups, obtained through sulphonation procedure (ii) showed the highest stability in terms of maintenance of their acidity after use in consecutive catalytic runs or leaching treatments. This was demonstrated both through evaluation of the regenerated catalysts in a consecutive esterification run and during a leaching resistance test in aqueous medium. Moreover, the developed sulphonated mesoporous phenolic resins are presented as novel support for the non-covalent immobilization of an L-phenylalanine derived chiral diamine organocatalyst for asymmetric aldol reactions. The immobilization is established by an acid–base interaction between the sulphonic acid group and the amine function. The acidity and in particular the electronic withdrawing environment of the sulphonic acid groups influence enormously the catalytic performance of the non-covalent immobilized chiral diamine catalyst (aromatic > aliphatic). - Highlights: ? Different types of sulphonation procedures for mesoporous phenolic resins. ? Influence of acidity and electronic withdrawing environment. ? Novel support for non-covalent immobilization of chiral diamine catalyst. ? Catalytic performance in esterification and asymmetric aldol condensation. ? Demonstration of leaching resistance in aqueous medium

43

Effects of press pressures on glue line thickness and properties of laminated veneer lumber glued with phenol formaldehyde adhesive  

OpenAIRE

The effects of press pressure on glue line thickness (GLT) and properties of laminated veneer lumbers (LVLs) manufactured from half-round sliced I-214 hybrid poplar clone veneers with phenol formaldehyde adhesives were determined. The results showed that press pressures significantly influenced GLT and properties of LVLs. Results of higher specific gravity, thickness swelling ratio, and mechanical properties, but lower GLT and water absorption ratio were attributed to higher press pressure us...

Ramazan Kurt; Muhammet Cil,

2012-01-01

44

Influence of nitrogen-containing phenol-formaldehyde oligomer on sorptive properties of macroporous polymer impregnated with tributylphosphate  

International Nuclear Information System (INIS)

Distribution of scandium(3), zirconium(4), niobium(5), molybdenum(6), cadmium(2), indium(3), tellurium(4) and uranium(6) between HCl aqueous solutions and macroporous polymer sorbent impregnated by a mixture of nitrogen-containing phenol-formaldehyde resol oligomer (Yarrezin B) and tributylphosphate is studied. It is ascertained that increase in distribution factors of the complexes extracted by the impregnated sorbent compared to solvent extraction stems from the absence of extractant association in the sorbent phase

45

Preparation and thermal properties of mesoporous silica/phenolic resin nanocomposites via in situ polymerization  

Directory of Open Access Journals (Sweden)

Full Text Available In order to enhance the adhesion between inorganic particles and polymer matrix, in this paper, the mesoporous silica SBA-15 material was synthesized by the sol-gel method. The surface of SBA-15 was modified using ?-glycidyloxypropyltrimethoxysilane (GOTMS as a coupling agent, and then mesoporous silica/phenolic resin (SBA-15/PF nanocomposites were prepared via in situ polymerization. The structural parameters and physical properties of SBA-15, SBA-15-GOTMS (SBA-15 surface treated using GOTMS as coupling agents and E-SBA-15/PF (SBA-15/PF nanocomposites extracted using ethanol as solvent were characterized by X-ray diffraction (XRD, N2 adsorption-desorption, Fourier transform infrared spectroscopy (FTIR, scanning electron microscopy (SEM, transmission electron microscopy (TEM and thermogravimetric analysis (TGA. The thermal properties of the nanocomposites were studied by differential scanning calorimetry (DSC and thermogravimetric analysis (TGA. The results demonstrated that the GOTMS were successfully grafted onto the surface of SBA-15, and chemical bonds between PF and SBA-15-GOTMS were formed after in situ polymerization. In addition, it is found that the in situ polymerization method has great effects on the textural parameters of SBA-15. The results also showed that the glass transition temperatures and thermal stability of the PF nanocomposites were obviously enhanced as compared with the pure PF at silica contents between 1–3 wt%, due to the uniform dispersion of the modified SBA-15 in the matrix.

J. Lv

2012-10-01

46

Investigating the possibility of using phenol-formaldehyde polymer as a nuclear gamma ray shield  

International Nuclear Information System (INIS)

Resol polymer (as a type of phenol-formaldehyde polymer) was synthesized from phenol and formalin of 40% concentration by a melt-condensation technique. Resol polymers were characterized by IR spectroscopy and elemental analysis of C and H. The possibility of using such a polymer as nuclear gamma ray shield was investigated. Three different forms of the polymer (polymer without additive, polymer with 5% by weight of Pb and polymer with 25% by weight of Pb) were used as a single shield. The attenuation coefficient (?) and buildup factor (B) were measured and analyzed for all three forms. Different gamma ray energies were chosen by using two gamma ray sources; namely 60Co and 137Cs, where 60Co has a half life time of 5.2714 years, with a activity level of 0.00837 mCi = 3.0954 x 105 Bq and two energy peaks of 1.332 MeV and 1.173 MeV, whereas 137Cs has a half life time of 30.04 years, an activity level of 0.0880 mCi = 3.2 x 106 Bq and an energy peak of 0.66 MeV. The additives have observable effects on the investigated parameters. In particular, it is found that by increasing the Pb additive to the polymer the attenuation coefficient (?) increases also, and at the same time the buildup factor (B) decreases. It was also found that the hardness of the polymer increases with time of exposure to radiation. (authors)

47

The influence of the diluent nature on scandium extraction by the phenol-formaldehyde resol oligomer yarrezin B  

International Nuclear Information System (INIS)

The paper studies the effect of diluent nature on scandium extraction by Yarrezin B phenol-formaldehyde resol oligomer using n-octan, toluene, chloroform, n-octanol and kerosene as an example. Correlation coefficients of dependences of scandium distribution factor on some parameters of diluents are calculated. Possibility to use some parameters of diluents to predict their effect on extraction indices is determined. Hildebrandt solubility parameter of extracting agent and parameters of extracting agent-diluent interaction according to Flory-Haggins are calculated. 13 refs., 2 figs., 4 tabs

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Proton conductivity of naphthalene sulfonate formaldehyde resin-doped mesoporous niobium and tantalum oxide composites.  

Science.gov (United States)

Proton conductivity in a series of mesoporous niobium and tantalum metal oxide (mX2 O5 ) composites of naphthalene sulfonic acid formaldehyde resin (NSF) that are resistant to moisture loss at temperatures greater than 50?°C is reported. The investigation focuses on the effect to proton conductivity by changing pore size and metal in the mesostructure of the mX2 O5 system and thus, a series of mX2 O5 -NSF composites were synthesized with C6 , C12 , and C18 templates. These were characterized by XRD, thermogravimetric analysis, nitrogen adsorption, and scanning TEM and then studied using impedance spectroscopy to establish proton conductivity values at various temperatures ranging from 25 to 150?°C. The most promising sample displayed a conductivity of 21.96?mS?cm(-1) at 100?°C, surpassing the literature value for Nafion 117 (ca. 8?mS?cm(-1) ). (1) H and (13) C solid state NMR studies the mX2 O5 -NSF composites demonstrate that the oligomeric nature of the NSF is preserved while in contact with the mX2 O5 surface, thus facilitating conductivity. PMID:25209169

Turley, Jonathan P; Romer, Frederik; Trudeau, Michel L; Dias, Marcos L; Smith, Mark E; Hanna, John V; Antonelli, David M

2015-01-01

49

The nature of ion exchange selectivity of phenol-formaldehyde sorbents with respect to cesium and rubidium ions  

Science.gov (United States)

The structure of aqua complexes of alkali metal ions Me+(H2O) n , n = 1-6, where Me is Li, Na, K, Rb, and Cs, and complexes of 2,6-dimethylphenolate anion (CH3)2PhO- selected as a model of the elementary unit of phenol-formaldehyde ion exchanger with hydrated alkali metal cations Me+(H2O) n , n = 0-5, was studied by the density functional method. The energies of successive hydration of the cations and the energies of binding of alkali metal hydrated cations with (CH3)2PhO- depending on the number of water molecules n were calculated. It was shown that the dimethylphenolate ion did not have specific selectivity with respect to cesium and rubidium ions. The energies of hydration and the energies of binding of alkali metal cations with (CH3)2PhO- decreased in the series Li+ > Na+ > K+ > Rb+ > Cs+ as n increased. The conclusion was drawn that the reason for selectivity of phenol-formaldehyde and other phenol compounds with respect to cesium and rubidium ions was the predomination of the ion dehydration stage in the transfer from an aqueous solution to the phenol phase compared with the stage of binding with ion exchange groups.

Kargov, S. I.; Shelkovnikova, L. A.; Ivanov, V. A.

2012-05-01

50

Studies on Glass Reinforced Epoxy Resin Using Vulkadur- A as Crosslinking Agent both in Presence and Absence of Carbon Black and other Non black Fillers  

Directory of Open Access Journals (Sweden)

Full Text Available Epoxy resin can be reinforced with glass (fabric form in presence of Vulkadur-A, a phenol formaldehyde resin containing a hardening agent. Overall enhancement in mechanical properties has been found stocks cured with Vulkadur-A containing 2.5 parts of carbon black as filler.

T. K. Ghosh

2014-03-01

51

Investigation of utilization of process of polyethylene waste of low density for creation of competitive materials with application of phenol formaldehyde oligomers  

International Nuclear Information System (INIS)

Full text: The possibility of the utilization of low density polyethylene wastes by means of their modification with phenol formaldehyde oligomers (Ph FO) and PhFO with the thiourathenes has been investigation. Theology properties of the investigated systems showed that the obtained compositions can be able to be processed by the ordinary methods such as extrusion and casting

52

Effects of press pressures on glue line thickness and properties of laminated veneer lumber glued with phenol formaldehyde adhesive  

Directory of Open Access Journals (Sweden)

Full Text Available The effects of press pressure on glue line thickness (GLT and properties of laminated veneer lumbers (LVLs manufactured from half-round sliced I-214 hybrid poplar clone veneers with phenol formaldehyde adhesives were determined. The results showed that press pressures significantly influenced GLT and properties of LVLs. Results of higher specific gravity, thickness swelling ratio, and mechanical properties, but lower GLT and water absorption ratio were attributed to higher press pressure uses. Optimum properties were obtained by using a press pressure of 10 kg cm-2 in relation to GLT and properties of LVLs. Significant relationships were found between GLT and mechanical properties. GLT may provide reliable information to determine wood bonding quality and may be used for non-destructive evaluation of mechanical properties of wood composites in the future.

Ramazan Kurt

2012-11-01

53

Hydrogen Bonding-Mediated Microphase Separation during the Formation of Mesoporous Novolac-Type Phenolic Resin Templated by the Triblock Copolymer, PEO-b-PPO-b-PEO  

Directory of Open Access Journals (Sweden)

Full Text Available After blending the triblock copolymer, poly(ethylene oxide-b-propylene oxide-b-ethylene oxide (PEO-b-PPO-b-PEO with novolac-type phenolic resin, Fourier transform infrared spectroscopy revealed that the ether groups of the PEO block were stronger hydrogen bond acceptors for the OH groups of phenolic resin than were the ether groups of the PPO block. Thermal curing with hexamethylenetetramine as the curing agent resulted in the triblock copolymer being incorporated into the phenolic resin, forming a nanostructure through a mechanism involving reaction-induced microphase separation. Mild pyrolysis conditions led to the removal of the PEO-b-PPO-b-PEO triblock copolymer and formation of mesoporous phenolic resin. This approach provided a variety of composition-dependent nanostructures, including disordered wormlike, body-centered-cubic spherical and disorder micelles. The regular mesoporous novolac-type phenolic resin was formed only at a phenolic content of 40–60 wt %, the result of an intriguing balance of hydrogen bonding interactions among the phenolic resin and the PEO and PPO segments of the triblock copolymer.

Wei-Cheng Chu

2013-11-01

54

Efficient removal of aniline by a water-compatible microporous and mesoporous hyper-cross-linked resin and XAD-4 resin: A comparative study  

Science.gov (United States)

A novel water-compatible microporous and mesoporous hyper-cross-linked resin modified with phenolic hydroxyl group (named as GQ-03) was synthesized to remove aniline in aqueous solution as compared with XAD-4. The maximum adsorption capacity of GQ-03 emerged at the molecular state for both aniline and p-cresol while the pH dependency trend of aniline adsorbed onto XAD-4 was accordant with the dissociation curve of aniline. The ionic strength influenced the adsorption obviously. The pseudo-first-order rate equation could describe the adsorption process of aniline onto GQ-03 in two stages while this equation could characterize the entire adsorption process of XAD-4. The adsorption isotherms could be correlated to the Freundlich model, higher KF and n values for GQ-03 than XAD-4. The breakthrough capacity and the total adsorption capacity of GQ-03 and XAD-4 was up to 47.2 mg mL-1 and 28.3 mg mL-1, 271.7 mg mL-1 and 115.6 mg mL-1, respectively. The size matching between the pore diameter of GQ-03 and the molecular size of aniline, and hydrogen bonding between GQ-03 and aniline resulted in the larger adsorption capacity.

Xiao, Guqing; Long, Liping

2012-06-01

55

Reactivity of phenol-formaldehyde microspheres in their reactions with PCl3, VOCl3, and CrO2Cl2 vapors  

International Nuclear Information System (INIS)

Products of interaction between vapors of PCl3, VOCl3, and CrO2Cl2 and microspheres of phenol-formaldehyde polymer were studied by the methods of IR and X-ray photoelectron spectroscopy to investigate processes occurring in the process of modifying solid polymer matrix by volatile low-molecular reagents. It was ascertained that grafting of the modifying additions takes place both by means of hydrogen atoms substitution in phenol hydroxylic groups and at the expense of redox reactions of element introduced, vanadium and chromium specifically, with reactive centers of polymer matrix

56

Chemical derivation to enhance the chemical/oxidative stability of resorcinol-formaldehyde (R-F) resin  

International Nuclear Information System (INIS)

Tank wastes at Hanford and SRS contain highly alkaline supernate solutions of conc. Na, K nitrates with large amounts of 137Cs. It is desirable to remove and concentrate the highly radioactive fraction for vitrification. One candidate ion exchange material for removing the radiocesium is R-F resin. This report summarizes studies into synthesis and characterization of 4-derivatized R-F resins prepared in pursuit of more chemically/oxidatively robust resin. 85% 4-fluororesorcinol/15% phenol formaldehyde resin appears to have good stability in alkaline solution, although there may be some nucleophilic displacement reaction during synthesis; further studies are needed

57

Kinetics of Chemical Changes in Phenol Formaldehyde Based Polymeric Films Etched in N2O and O2 Inductively Coupled Plasmas: A Comparative Study  

Science.gov (United States)

This paper reports on investigation of surface chemistry and etch rates of phenol formaldehyde based polymer after N2O and O2 radio frequency (RF) inductively coupled plasma processing depend on exposure time. By using X-ray photoelectron spectroscopy, it was shown that oxygen and nitrogen oxide plasma expositions both lead to similar changes in the chemical composition of polymer. The nitrogen oxide plasma does not lead to any significant increase of concentration of nitrogen-containing groups on the polymer. It was confirmed that the mechanism of photoresist destruction in the N2O discharge was generally identical to that in the O2 plasma. Furthermore, the surface interactions with the polymer of nitrogen-containing active species could be neglected.

Kwon, Kwang-Ho; Min, Nam-Ki; Kang, Seung-Youl; Baek, Kyu-Ha; Suh, Kyung Soo; Alexandrovich Shutov, Dmitriy

2009-08-01

58

Microporosity development in phenolic resin-based mesoporous carbons for enhancing CO2 adsorption at ambient conditions  

Science.gov (United States)

Soft-templating method was used to prepare mesoporous carbons. The synthesis in the presence of hydrochloric and citric acids involved resorcinol and formaldehyde as carbon precursors and triblock copolymer Pluronic F127 as a template. The as-synthesized samples underwent carbonization in flowing nitrogen at various temperatures; namely 600 °C, 700 °C and 800 °C. Two routes were used to develop microporosity in the mesoporous carbons studied. The first one involved introduction of tetraethyl orthosilicate to the reaction system. After silica dissolution with NaOH, an increase in microporosity was observed. The second method, chemical activation with KOH at 700 °C, was explored as an alternative approach to create microporosity. It is noteworthy that the TEOS addition not only led to the development of microporosity but also to some improvement of mesoporosity. The post-synthesis KOH activation resulted in more significant increase in the microporosity as compared to the samples obtained by TEOS-assisted synthesis. The mesopore volume was somewhat lower for activated carbons as compared to that in mesoporous carbons. Both methods resulted in micro-mesoporous carbons with good adsorption properties; for instance, in the case of carbons prepared in the presence of TEOS, the best sample exhibited BET surface area of 1463 m2/g and the total pore volume of 1.31 cm3/g. For the KOH activated carbons the best adsorption parameters were as follows: the specific surface area = 1906 m2/g, and the total pore volume = 0.98 cm3/g. Both procedures used for microporosity development afforded carbons with good adsorption properties that can be useful for applications such as CO2 adsorption, air and water purification.

Choma, Jerzy; Jedynak, Katarzyna; Fahrenholz, Weronika; Ludwinowicz, Jowita; Jaroniec, Mietek

2014-01-01

59

Synchrotron-based X-ray Fluorescence Microscopy in Conjunction with Nanoindentation to Study Molecular-Scale Interactions of Phenol-Formaldehyde in Wood Cell Walls.  

Science.gov (United States)

Understanding and controlling molecular-scale interactions between adhesives and wood polymers are critical to accelerate the development of improved adhesives for advanced wood-based materials. The submicrometer resolution of synchrotron-based X-ray fluorescence microscopy (XFM) was found capable of mapping and quantifying infiltration of Br-labeled phenol-formaldehyde (BrPF) into wood cell walls. Cell wall infiltration of five BrPF adhesives with different average molecular weights (MWs) was mapped. Nanoindentation on the same cell walls was performed to assess the effects of BrPF infiltration on cell wall hygromechanical properties. For the same amount of weight uptake, lower MW BrPF adhesives were found to be more effective at decreasing moisture-induced mechanical softening. This greater effectiveness of lower MW phenolic adhesives likely resulted from their ability to more intimately associate with water sorption sites in the wood polymers. Evidence also suggests that a BrPF interpenetrating polymer network (IPN) formed within the wood polymers, which might also decrease moisture sorption by mechanically restraining wood polymers during swelling. PMID:25756624

Jakes, Joseph E; Hunt, Christopher G; Yelle, Daniel J; Lorenz, Linda; Hirth, Kolby; Gleber, Sophie-Charlotte; Vogt, Stefan; Grigsby, Warren; Frihart, Charles R

2015-04-01

60

Encapsulation of dye molecules into mesoporous polymer resin and mesoporous polymer-silica films by an evaporation-induced self-assembly method  

International Nuclear Information System (INIS)

Polymer resin and polymer-silica films with highly ordered mesostructure have been used as host materials to encapsulate DCM (4-(dicyanomethylene) -2-methyl-6-(4-dimethylaminostyryl)-4h-pyran), a kind of fluorescent dye, through evaporation-induced self-assembly method (EISA). After encapsulation, the composites show significant blue-shift in photoluminescence (PL) spectra. Particularly, by changing the excitation wavelength, the samples show different emission bands. These phenomena are related to the mesostructure and the positions of DCM molecules in the host.

61

Mesoporous Carbon-based Materials for Alternative Energy Applications  

Science.gov (United States)

Increasing concerns for the escalating issues activated by the effect of carbon dioxide emissions on the global climate from extensive use of fossil fuels and the limited amount of fossil resources has led to an in-depth search for alternative energy systems, primarily based on nuclear or renewable energy sources. Recent innovations in the production of more efficient devices for energy harvesting, storage, and conversion are based on the incorporation of nanostructured materials into electrochemical systems. The aforementioned nano-electrochemical energy systems hold particular promise for alternative energy transportation related technologies including fuel cells, hydrogen storage, and electrochemical supercapacitors. In each of these devices, nanostructured materials can be used to increase the surface area where the critical chemical reactions occur within the same volume and mass, thereby increasing the energy density, power density, electrical efficiency, and physical robustness of the system. Durable corrosion resistant carbon support materials for fuel cells have been designed by adding conductive low cost carbon materials with chemically robust ceramic materials. Since a strict control of the pore size is mandatory to optimize properties for improved performance, chemical activation agents have been utilized as porogens to tune surface areas, pore size distributions, and composition of carbon-based mesoporous materials. Through the use of evaporative self-assembly methods, both randomly disordered and surfactant-templated, ordered carbon-silica nanocomposites have been synthesized with controlled surface area, pore volume, and pore size ranging from 50-800 m2/g, 0.025-0.75 cm3/g, and 2-10 nm, respectively. Multi-walled carbon nanotubes (MWNTs) ranging from 0.05-1.0 wt. % were added to the aforementioned carbon-silica nanocomposites, which provided an additional increase in surface area and improved conductivity. Initially, a conductivity value of 0.0667 S/cm was measured for the composite without carbon nanotubes and the conductivity value improved by over an order of magnitude to 1 S/cm with the addition of 0.5 wt.% CNTs. Triggered by dispersion issues, the agglomeration of MWNTs during the drying process prevented each nanotube from being loaded over a maximum interfacial area. In order to improve the dispersion of carbon nanotubes within the carbon-silica network, electrospinning was explored as a method to improve the alignment of the carbon nanotubes. The electrospun fibers produced with the highest concentration of MWNTs at 1.0 wt.% produced the largest surface area and electrical conductivity values of 333.36 m2/g and 2.09 S/cm, respectively. Capacitance measurements were calculated to examine if improved conductivity results in higher capacitance values. The best capacitance performance was 148 F/g from a carbon-based mesoporous composite with 0.5 wt. % MWNTs in an aqueous electrolyte with a 2.0 mV/s scan rate. An 80% increase in capacitance occurs with the addition of 0.5 wt. % MWNTs. This is in the range of capacitance values produced by hierarchically ordered mesoporous-microporous carbons, reported at 180 F/g. Fibrous carbon tubes assembled from hydrofluoric acid etched perylenetetracarboxylic diimide bridged silsesquioxane (PDBS) were capable of hydrogen adsorption on the order of 1.3-2.5 wt. % at 77K. Lastly chemically activated phenol-formaldehyde resins produced microporous carbon with 1500 m3/g surface areas and pore sizes ranging from 0.3-0.5 nm, which has potential for asymmetric super-capacitor electrodes. Judicious control over the composition and pore structure of carbon-based nanocomposites can lead to improved performance of various alternative energy materials.

Cross, Kimberly Michelle

62

Synthesis of mesoporous silica@Co-Al layered double hydroxide spheres: layer-by-layer method and their effects on the flame retardancy of epoxy resins.  

Science.gov (United States)

Hierarchical mesoporous silica@Co-Al layered double hydroxide (m-SiO2@Co-Al LDH) spheres were prepared through a layer-by-layer assembly process, in order to integrate their excellent physical and chemical functionalities. TEM results depicted that, due to the electrostatic potential difference between m-SiO2 and Co-Al LDH, the synthetic m-SiO2@Co-Al LDH hybrids exhibited that m-SiO2 spheres were packaged by the Co-Al LDH nanosheets. Subsequently, the m-SiO2@Co-Al LDH spheres were incorporated into epoxy resin (EP) to prepare specimens for investigation of their flame-retardant performance. Cone results indicated that m-SiO2@Co-Al LDH incorporated obviously improved fire retardant of EP. A plausible mechanism of fire retardant was hypothesized based on the analyses of thermal conductivity, char residues, and pyrolysis fragments. Labyrinth effect of m-SiO2 and formation of graphitized carbon char catalyzed by Co-Al LDH play pivotal roles in the flame retardance enhancement. PMID:25062606

Jiang, Shu-Dong; Bai, Zhi-Man; Tang, Gang; Song, Lei; Stec, Anna A; Hull, T Richard; Hu, Yuan; Hu, Wei-Zhao

2014-08-27

63

EPICOR-II resin degradation results from first resin samples of PF-8 and PF-20  

International Nuclear Information System (INIS)

The 28 March 1979 accident at Three Mile Island Unit 2 released approximately 560,000 gallons of contaminated water to the Auxiliary and Fuel Handling Buildings. The water was decontaminated using a demineralization system called EPICOR-II developed by Epicor, Inc. The Low-Level Waste Data Base Development - EPICOR-II Resin/Liner Investigation Project is studying the chemical and physical conditions of the synthetic ion exchange resins found in several EPICOR-II prefilters. This report summarizes results and analyses of the first sampling of ion exchange resins from EPICOR-II prefilters PE-8 and -20. Results are compared with baseline data from tests performed on unirradiated Epicor, Inc. resins to determine if degradation has occurred due to the high internal radiation dose received by the EPICOR-II resins. Results also are compared with recent findings on resin degradation by Battelle Columbus Laboratories and Brookhaven National Laboratory. Analyses comparing test results of resins from EPICOR-II prefilters PF-8 and -20 with unirradiated resins obtained from Epicor, Inc. show resin degradation has occurred in some of the EPICOR-II resins examined. The mechanism of degradation is compared with work of other researchers and is consistent with their findings. The strong acid cation resins (divinylbenzene, styrene base structure) are losing effective cross-linking along with scission of functional groups and are experiencing first an increase and eventually a decrease rst an increase and eventually a decrease in total exchange capacity as the absorbed radiation dose increases. The phenolic cation resins (phenol-formaldehyde base structure) show a loss of effective cross-linking and oxidation of the polymer chain. Analyses of resins removed from EPICOR-II prefilters PF-8 and -20 over the next several years should show a further increase in degradation

64

Weather ability studies of phenolic resin coated woods and glass fiber reinforced laminates  

International Nuclear Information System (INIS)

Phenolic resins have made a major breakthrough in the field of high technology in 80's. These are now active participants of high tech' areas ranging from electronics, computers, communication, outer space, aerospace, advanced materials, bio materials and technology. A phenol - formaldehyde (1:1.5) resin having resin content of 70% synthesized in the laboratory has been applied for wood coating and reinforcing glass fiber. The weatherability and solvent resistance of these items have been studied and results discussed keeping in view the envisaged application for structural materials and chemical equipment. The toxic materials released during contact with solvents for chemical applications and during degradation general have been monitored. The results are discussed with reference to environmental pollution due to these resins and their composites under different conditions. (authors)

65

A nanospherical ordered mesoporous Lewis acid polymer for the direct glycosylation of unprotected and unactivated sugars in water.  

Science.gov (United States)

The design of robust solid catalysts which can selectively synthesize highly functionalized carbohydrate derivatives from unprotected and unactivated simple sugars in water is an outstanding challenge. Herein we describe the preparation of a novel nanospherical ordered mesoporous Lewis acid polymer (Sc(OTf)2-NSMP) by functionalizing the mesoporous phenol-formaldehyde polymer framework with scandium triflate groups. In the C-glycosylation reaction between D-glucose and dimedone with the Sc(OTf)2-NSMP catalyst, the conversion was 99% and the yield of xanthone-C-glucoside reached 92% after 2?days, which exceeded the previous best results. It was shown that other xanthone glycosides can be obtained from various sugars with moderate to good yields. Furthermore, the catalyst can be easily recovered and reused at least seven times without loss of catalytic activity. PMID:25055738

Zhang, Fang; Liang, Chao; Wu, Xiaotao; Li, Hexing

2014-08-01

66

Hand/face/neck localized pattern: sticky problems--resins.  

Science.gov (United States)

Plastic resin systems have an increasingly diverse array of applications but also induce health hazards, the most common of which are allergic and irritant contact dermatitis. Contact urticaria, pigmentary changes, and photoallergic contact dermatitis may occasionally occur. Other health effects, especially respiratory and neurologic signs and symptoms, have also been reported. These resin systems include epoxies, the most frequent synthetic resin systems to cause contact dermatitis, (meth)acrylics, polyurethanes, phenol-formaldehydes, polyesters, amino resins (melamine-formaldehydes, urea-formaldehydes), polyvinyls, polystyrenes, polyolefins, polyamides and polycarbonates. Contact dermatitis usually occurs as a result of exposure to the monomers and additives in the occupational setting, although reports from consumers, using the raw materials or end products periodically surface. Resin- and additive-induced direct contact dermatitis usually presents on the hands, fingers, and forearms, while facial, eyelid, and neck involvement may occur through indirect contact, eg, via the hands, or from airborne exposure. Patch testing with commercially available materials, and in some cases the patient's own resins, is important for diagnosis. Industrial hygiene prevention techniques are essential to reduce contact dermatitis when handling these resin systems. PMID:19580919

Cao, Lauren Y; Sood, Apra; Taylor, James S

2009-07-01

67

Modeling the Effects of Velocity, Spin, Frictional Coefficient, and Impact Angle on Deflection Angle in Near-elastic Collisions of Phenolic Resin Spheres  

CERN Document Server

A simple model is outlined to describe the collision of cast phenol-formaldehyde resin spheres such as the balls used in the parlor game of pocket billiards, based in part on the famous analysis of elastic collisions developed by Heinrich Hertz over 100 years ago. The analysis treats the normal and tangential components of the initial sphere's velocity independently as it collides with a stationary identical second sphere. The collective effects of these and other parameters on the trajectory of the second sphere are provided in the conclusions.

Crown, S C

2004-01-01

68

Hydrogen Bonding-Mediated Microphase Separation during the Formation of Mesoporous Novolac-Type Phenolic Resin Templated by the Triblock Copolymer, PEO-b-PPO-b-PEO  

OpenAIRE

After blending the triblock copolymer, poly(ethylene oxide-b-propylene oxide-b-ethylene oxide) (PEO-b-PPO-b-PEO) with novolac-type phenolic resin, Fourier transform infrared spectroscopy revealed that the ether groups of the PEO block were stronger hydrogen bond acceptors for the OH groups of phenolic resin than were the ether groups of the PPO block. Thermal curing with hexamethylenetetramine as the curing agent resulted in the triblock copolymer being incorporated into the phenolic resin, f...

Wei-Cheng Chu; Shiao-Wei Kuo; Jheng-Guang Li; Shih-Fan Chiang

2013-01-01

69

Large-scale synthesis of onion-like carbon nanoparticles by carbonization of phenolic resin  

International Nuclear Information System (INIS)

Onion-like carbon nanoparticles have been synthesized on a large scale by carbonization of phenolic-formaldehyde resin at 1000 oC with the aid of ferric nitrate (FN). The effects of FN loading content on the yield, morphology and structure of carbonized products were investigated using transmission electron microscopy (TEM), high-resolution TEM and X-ray diffraction. It was found that the onion-like carbon nanoparticles, which had a narrow size distribution ranging from 30 to 50 nm, were composed mainly of quasi-spherically concentric shells of well-aligned graphene layers with interlayer spacing of 0.336 nm. Based on the results of the investigation, the formation mechanism of onion-like carbon nanoparticles was also discussed

70

Synthesis, structural characterization, and performance evaluation of resorcinol-formaldehyde (R-F) ion-exchange resin  

International Nuclear Information System (INIS)

The 177 underground storage tanks at the DOE's Hanford Site contain an estimated 180 million tons of high-level radioactive wastes. It is desirable to remove and concentrate the highly radioactive fraction of the tank wastes for vitrification. Resorcinol-formaldehyde (R-F) resin, an organic ion-exchange resin with high selectivity and capacity for the cesium ion, which is a candidate ion-exchange material for use in remediation of tank wastes. The report includes information on the structure/function analysis of R-F resin and the synthetic factors that affect performance of the resin. CS-100, a commercially available phenol-formaldehyde (P-F) resin, and currently the baseline ion-exchanger for removal of cesium ion at Hanford, is compared with the R-F resin. The primary structural unit of the R-F resin was determined to consist of a 1,2,3,4-tetrasubstituted resorcinol ring unit while CS-100, was composed mainly of a 1,2,4-trisubstituted ring. CS-100 shows the presence of phenoxy-ether groups, and this may account for the much lower decontamination factor of CS-100 for cesium ion. Curing temperatures for the R-F resin were found to be optimal at 105--130C. At lower temperatures, insufficient curing, hence crosslinking, of the polymer resin occurs and selectivity for cesium drops. Curing at elevated temperatures leads to chemical degradation. Optimal particle size for R-F resin is in the range of 20--50 mesh-sized particles. R-F resin undergoes chemical degradation or oxidation which destroys ion-exchange sites. The ion-exchange sites (hydroxyl groups) are converted to quinones and ketones. CS-100, though it has much lower performance for cesium ion-exchange, is significantly more chemically stable than R-F resin. To gamma radiation, CS-100 is more radiolytically stable than R-F resin

71

Screw Withdrawal Resistance of Moulded Laminated Veneer Oil Palm (MLVOP Bonded with Formaldehyde Resins  

Directory of Open Access Journals (Sweden)

Full Text Available A research was conducted to discover the screw withdrawal resistance of moulded laminated veneer lumbers made from oil palm trunks (MLVOP. The MLVOPs were manufactured separately with three different veneer arrangements namely S100% (each ply came from the superior part, SS-CI (surface superior and core inferior and S-I (alternate superior and inferior parts. The veneers were divided into two groups. One group of veneers was bonded with urea formaldehyde (UF resin to MLVOPs and the other was bonded with phenol formaldehyde (PF. The veneers were pressed at a temperature of 110ºC for 20 min. The pressures applied to press the veneers to MLVOPs were 1500 psi, 2000 psi and 2500 psi. The study showed that the pressures and S-I veneer arrangement gave significant effects to the screw withdrawal resistance of UF-bonded and PF-bonded MLVOPs. MLVOPs with S-I veneer arrangement achieved the highest mean screw withdrawal resistance values when they were bonded with UF resin then pressed with 1500 psi and 2500 psi and bonded with PF resin and pressed with 1500 psi. The values were 848 N, 884 N and 496 N respectively. Overall, UF-bonded MLVOPs were better than those bonded with PF resin.

Abdul Hamid Saleh

2012-05-01

72

"Bricks and mortar" self-assembly approach to graphitic mesoporous carbon nanocomposites  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous carbon materials do not have sufficient ordering at the atomic scale to exhibit good electronic conductivity. To date, mesoporous carbons having uniform mesopores and high surface areas have been prepared from partially-graphitizable precursors in the presence of templates. High temperature thermal treatments above 2000 °C, which are usually required to increase conductivity, result in a partial or total collapse of the mesoporous structures and reduced surface areas induced by growth of graphitic domains, limiting their applications in electric double layer capacitors and lithium-ion batteries. In this work, we successfully implemented a “brick-and-mortar” approach to obtain ordered graphitic mesoporous carbon nanocomposites with tunable mesopore sizes below 850 °C without using graphitization catalysts or high temperature thermal treatments. Phenolic resin-based mesoporous carbons act as mortar to highly conductive carbon blacks and carbon onions (bricks). The capacitance and resistivity of final materials can be tailored by changing the mortar to brick ratios.

Fulvio, P. F.; Mayes, R.; Wang, X. Q.; Mahurin, S., M.; Bauer, J. C.; Presser, V.; McDonough, J.; Gogotsi, Y.; Dai, S.

2011-01-01

73

Brick-and-Mortar Self-Assembly Approach to Graphitic Mesoporous Carbon Nanocomposites  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous carbon materials do not have sufficient ordering at the atomic scale to exhibit good electronic conductivity. To date, mesoporous carbons having uniform mesopores and high surface areas have been prepared from partially-graphitizable precursors in the presence of templates. High temperature thermal treatments above 2000 C, which are usually required to increase conductivity, result in a partial or total collapse of the mesoporous structures and reduced surface areas induced by growth of graphitic domains, limiting their applications in electric double layer capacitors and lithium-ion batteries. In this work, we successfully implemented a 'brick-and-mortar' approach to obtain ordered graphitic mesoporous carbon nanocomposites with tunable mesopore sizes below 850 C without using graphitization catalysts or high temperature thermal treatments. Phenolic resin-based mesoporous carbons act as mortar to highly conductive carbon blacks and carbon onions (bricks). The capacitance and resistivity of final materials can be tailored by changing the mortar to brick ratios.

Dai, Sheng [ORNL; Fulvio, Pasquale F [ORNL; Mayes, Richard T [ORNL; Wang, Xiqing [ORNL; Mahurin, Shannon Mark [ORNL; Bauer, Christopher [ORNL; Presser, Volker [Drexel University; Mcdonough, John [Drexel University; Gogotsi, Yury [ORNL

2011-01-01

74

Mesoporous carbon materials  

Energy Technology Data Exchange (ETDEWEB)

A conductive mesoporous carbon composite comprising conductive carbon nanoparticles contained within a mesoporous carbon matrix, wherein the conductive mesoporous carbon composite possesses at least a portion of mesopores having a pore size of at least 10 nm and up to 50 nm, and wherein the mesopores are either within the mesoporous carbon matrix, or are spacings delineated by surfaces of said conductive carbon nanoparticles when said conductive carbon nanoparticles are fused with each other, or both. Methods for producing the above-described composite, devices incorporating them (e.g., lithium batteries), and methods of using them, are also described.

Dai, Sheng; Fulvio, Pasquale Fernando; Mayes, Richard T.; Wang, Xiqing; Sun, Xiao-Guang; Guo, Bingkun

2014-09-09

75

Multifunctional mesoporous silica catalyst  

Energy Technology Data Exchange (ETDEWEB)

The present invention provides bifunctional silica mesoporous materials, including mesoporous silica nanoparticles ("MSN"), having pores modified with diarylammonium triflate and perfluoroaryl moieties, that are useful for the acid-catalyzed esterification of organic acids with organic alcohols.

Lin, Victor Shang-Yi; Tsai, Chih-Hsiang; Chen, Hung-Ting; Pruski, Marek; Kobayashi, Takeshi

2015-03-31

76

Enhancing the Properties of Low Density Hardwood Dyera costulata Through Impregnation with Phenolic Resin Admixed with Formaldehyde Scavenger  

Directory of Open Access Journals (Sweden)

Full Text Available The formaldehyde emission, properties and decay durability of Dyera constulata wood, impregnated with low molecular weight phenol formaldehyde (LmwPF resin mixed with urea were investigated. The air-dry wood was impregnated with 20-40% LmwPF (Mw 600 mixed separately with urea (30% based on solid PF, partially cured at 60C for 30 min and subsequently heated at 150C for 60-120 min. The treatments had successfully reduced the formaldehyde emission (FE of the impreg and the degrees of reduction depend on curing time. Statistical analyses showed that the concentration of resin affected the density, stiffness, water absorption and thickness swelling, while the curing time affected the density, polymer loading, water absorption and thickness swelling. Impreg product had higher MOR, MOE and dimensional stability compared to the untreated wood. The treatments rendered the impreg product with approximately 20% in anti-swelling efficiency and had also changed the wood into highly resistant to fungal decay.

M.T. Paridah

2011-01-01

77

Novel bio-based thermoset resins based on epoxidized vegetable oils for structural adhesives  

Science.gov (United States)

Conventional engineered wood composites are bonded for the most part through formaldehyde-based structural adhesives such as urea formaldehyde (UF), melamine formaldehyde (MF), phenol formaldehyde (PF) and resorcinol formaldehyde (RF). Formaldehyde is a known human carcinogen; the occupational exposure and emission after manufacturing of these binders is raising more and more concern. With increasing emphasis on environmental issues, there is clear incentive to replace these hazardous conventional formaldehyde-based binders with cco-friendly resins having similar properties but derived from renewable sources, bearing in mind the economics of the structural wood composite industry. In this thesis, the curing reaction of bio-derived epoxy thermosets with inexpensive, low-toxicity precursors, including polyimines and amino acids was investigated. Epoxidized linseed oil (ELO) and epoxidized soybean oil (ESO) were successfully crosslinked with both branched polyethyleneimine (PEI) and triethylenetetramine (fETA). Epoxidized castor oil (ECO) was crosslinked with polyethyleneimine (PEI), having different molecular weights. Curing conditions were optimized through solvent uptake and soluble fraction analysis. Finally, the mechanical properties of the optimized compositions of rigid bioepoxies were evaluated using dynamic mechanical rheological testing (DMRT). While not as stiff as conventional materials, optimized materials have sufficient room temperature moduli to show promise for coatings and as binders in engineered wood products.

Sivasubramanian, Shivshankar

78

Composite material based on an ablative phenolic resin and carbon fibers  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, a technological procedure for the production of a molding compound based on short carbon fibers and an ablative phenol–formaldehyde resin for high temperature application was optimized. The starting raw materials were characterized and molding compounds with different fiber/matrix ratios and different fiber lengths were obtained. From the different laboratory samples, molded parts were made by thermocompression. The basic mechanical and thermal properties of the composites were determined. From the obtained results, the optimal fiber/matrix ratio was determined for a production of molding compound for high temperature application. The molding process of the composite material was optimized and all the parameters for good mechanical properties and high thermal stability of the composite were obtained. Optimization of the composite molding process was performed by the application of a numerical method for a planned experiment, i.e., a full three-factorial experimental design with variance of all three parameters (fiber length, temperature and time of the press cycle on two levels. The obtained mechanical properties (flexural strength: 247 MPa, modulus: 27.6 GPa, impact resistance: 110 (for test moldings 10 mm´10 mm and 91 kJ/m2 (for test moldings 15 mm´15 mm justified the application of this composite material in the automotive, leisure, military and other industries where high temperature resistance and high mechanical strength is required.

DIMKO DIMESKI

2009-04-01

79

Fabrication and Characterization of Inorganic Silver and Palladium Nanostructures within Hexagonal Cylindrical Channels of Mesoporous Carbon  

OpenAIRE

In this study, we prepared a mesoporous carbon with hexagonally packed mesopores through evaporation-induced self-assembly (EISA)—with the diblock copolymer poly(ethylene oxide-b-?-caprolactone) (PEO-b-PCL) as the template (EO114CL84), phenolic resin as the carbon precursor, hexamethylenetetramine (HMTA) as the curing agent, and star octakis-PEO-functionalized polyhedral oligomeric silsesquioxane (PEO–POSS) as the structure modifier—and subsequent carbonization. We then took the cylind...

Jheng-Guang Li; Cheng-Ying Tsai; Shiao-Wei Kuo

2014-01-01

80

Resin compositions  

International Nuclear Information System (INIS)

Resin compositions which are cross-linkable by high energy radiation and radical polymerization catalysts are provided. The resin compositions are obtained by blending (A) polyester resins and (B) condensates in the ratio of (A)/(B)=90/10 to 10/90, the polyester resin (A) containing side chain radicals which contain at least two ester bonds and at least one ?, ? -unsaturated olefinic bond obtained by the addition reaction of vinyl monomers containing glycidyl radicals, the condensate (B) consisting of unsaturated carboxylic acid including one (metha-)acryloid radical and one carboxylic radical in its molecules, polyol and/or an (metha-)acrylic vinyl monomer containing hydroxyl radicals, the condensate (B) may consist of a polycarboxylic acid and a (metha-)acrylic vinyl monomer containing hydroxyl radicals. The molecular weight of the polyester resin is preferably 300 to 5,000 and the hydroxyl value 20 to 200. The resin compositions thus obtained can be gelled quickly in a cross-linking process, particularly the process carried out by irradiation with high energy radiation such as ionizing radiation and ultraviolet light, which produces a cross-linked molding having excellent flexibility and adhesiveness. (Iwakiri, K.)

81

Fabrication and Characterization of Inorganic Silver and Palladium Nanostructures within Hexagonal Cylindrical Channels of Mesoporous Carbon  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, we prepared a mesoporous carbon with hexagonally packed mesopores through evaporation-induced self-assembly (EISA—with the diblock copolymer poly(ethylene oxide-b-?-caprolactone (PEO-b-PCL as the template (EO114CL84, phenolic resin as the carbon precursor, hexamethylenetetramine (HMTA as the curing agent, and star octakis-PEO-functionalized polyhedral oligomeric silsesquioxane (PEO–POSS as the structure modifier—and subsequent carbonization. We then took the cylindrical mesoporous carbon as a loading matrix, with AgNO3 and Pd(NO32 as metal precursors, to fabricate Ag nanowire/mesoporous carbon and Pd nanoparticle/mesoporous carbon nanocomposites, respectively, through an incipient wetness impregnation method and subsequent reduction under H2. We used transmission electron microscopy, electron diffraction, small-angle X-ray scattering, N2 isotherm sorption experiment, Raman spectroscopy, and power X-ray diffraction to investigate the textural properties of these nanometal/carbon nanocomposites. Most notably, the Raman spectra of the cylindrical mesoporous carbon, Ag/mesoporous carbon, and Pd/mesoporous carbon revealed interesting phenomena in terms of the ratios of the intensities of the D and G bands (ID/IG, the absolute scattering intensities, and the positions of the D bands.

Jheng-Guang Li

2014-06-01

82

Morphology control in mesoporous carbon films using solvent vapor annealing.  

Science.gov (United States)

Ordered mesoporous (2-50 nm) carbon films were fabricated using cooperative self-assembly of a phenolic resin oligomer with a novel block copolymer template (poly(styrene-block-N,N-dimethyl-n-octadecylamine p-styrenesulfonate), (PS-b-PSS-DMODA)) synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Due to the high Tg of the PS segment and the strong interactions between the phenolic resin and the PSS-DMODA, the segmental rearrangement is kinetically hindered relative to the cross-linking rate of the phenolic resin, which inhibits long-range ordering and yields a poorly ordered mesoporous carbon with a broad pore size distribution. However, relatively short exposure (2 h) to controlled vapor pressures of methyl ethyl ketone (MEK) yields significant improvements in the long-range ordering and narrows the pore size distribution. The average pore size increases as the solvent vapor pressure during annealing increases, but an upper limit of p/p0 = 0.85 exists above which the films dewet rapidly during solvent vapor annealing. This approach can be extended using mesityl oxide, which has similar solvent qualities to MEK, but is not easily removed by ambient air drying after solvent annealing. This residual solvent can impact the morphology that develops during cross-linking of the films. These results illustrate the ability to fine-tune the mesostructure of ordered mesoporous carbon films through simple changes in the processing without any compositional changes in the initial cast film. PMID:23394515

Qiang, Zhe; Xue, Jiachen; Cavicchi, Kevin A; Vogt, Bryan D

2013-03-12

83

Photochromic mesoporous hybrid coatings  

Science.gov (United States)

Spirooxazine (SO) photochromic molecules were trapped in sol-gel matrices. In order to increase the colourability and improve mechanical properties of sol-gel photochromic films, we present an original strategy in which SO photochromic molecules were dispersed in mesoporous organized films using the impregnation technique. Well-ordered organosilicate mesoporous coatings with the 3D-hexagonal symmetry were prepared by the sol-gel technique. These robust mesoporous films, which contain high amounts of hydrophobic methyl groups at the pore surface, offer optimized environments for photochromic dyes dispersed by impregnation technique. After impregnation by a spirooxazine solution, the photochromic response is only slightly slower when compared with mesostructured or soft sol-gel matrices, showing that mesoporous organized hybrid matrix are good host for photochromic dyes. Moreover, the molecular loading in films is easily adjustable in a large range using multi-impregnation procedure and increasing the film thickness leading to coatings for optical switching devices.

Raboin, L.; Matheron, M.; Gacoin, T.; Boilot, J.-P.

2008-09-01

84

Analysis of the Compounds from the BTEX Group, Emitted During Thermal Decomposition of Alkyd Resin  

Directory of Open Access Journals (Sweden)

Full Text Available Suitability of the given binding agent for the moulding sands preparation depends on the one hand on the estimation of technological properties of the sand and the mould made of it and the obtained casting quality and on the other hand on the assessment of this sand influence on the natural and working environment. Out of moulding sands used in the foundry industry, sands with organic binders deserve a special attention. These binders are based on synthetic resins, which ensure obtaining the proper technological properties and sound castings, however, they negatively influence the environment. If in the initial state these resins are not very dangerous for people and for the environment, thus under an influence of high temperatures they generate very harmful products, being the result of their thermal decomposition. Depending on the kind of the applied resin (phenol-formaldehyde, urea, furfuryl, urea–furfuryl, alkyd under an influence of a temperature such compounds as: furfuryl alcohol, formaldehyde, phenol, BTEX group (benzene, toluene, ethylbenzene, xylene, and also polycyclic aromatic hydrocarbons (PAH can be formed and released.The aim of the study was the development of the method, selection of analytical methods and the determination of optimal conditionsof formation compounds from the BTEX group. An emission of these components constitutes one of the basic criteria of the harmfulnessassessment of binders applied for moulding and core sands. Investigations were carried out in the specially designed set up for the thermal decomposition of organic substances in a temperature range: 5000C – 13000C at the laboratory scale. The object for testing was alkyd resin applied as a binding material for moulding sands. Within investigations the minimal amount of adsorbent necessary for the adsorption of compounds released during the decomposition of the resin sample of a mass app. 15 mg was selected. Also the minimal amount of solvent needed for the desorption of compounds adsorbed in the column with adsorbent was found. The temperature range, in which the maximal amounts of benzene, toluene, ethylobenzene and xylenes are released from the resin, was defined. The qualitative and quantitative analyses of compounds from the BTEX group were performed by means of the gas chromatography combined with the mass spectrometry (GC/MS.

M. Kubecki

2012-09-01

85

Bicontinuous mesoporous carbon thin films via an order-order transition.  

Science.gov (United States)

Bicontinuous mesoporous carbon films are fabricated by cooperative self-assembly of phenolic resin and amphiphilic triblock copolymer via an order-order transition from cylinders to gyroid. The film morphology is strongly influenced by the details of processing, including age of the resol, resol?:?template ratio, and the solvent vapor annealing process. PMID:25207485

Deng, Guodong; Zhang, Yuanzhong; Ye, Changhuai; Qiang, Zhe; Stein, Gila E; Cavicchi, Kevin A; Vogt, Bryan D

2014-10-28

86

Mesoporous carbon materials  

Energy Technology Data Exchange (ETDEWEB)

The invention is directed to a method for fabricating a mesoporous carbon material, the method comprising subjecting a precursor composition to a curing step followed by a carbonization step, the precursor composition comprising: (i) a templating component comprised of a block copolymer, (ii) a phenolic compound or material, (iii) a crosslinkable aldehyde component, and (iv) at least 0.5 M concentration of a strong acid having a pKa of or less than -2, wherein said carbonization step comprises heating the precursor composition at a carbonizing temperature for sufficient time to convert the precursor composition to a mesoporous carbon material. The invention is also directed to a mesoporous carbon material having an improved thermal stability, preferably produced according to the above method.

Dai, Sheng; Wang, Xiqing

2013-08-20

87

Templating mesoporous zeolites  

DEFF Research Database (Denmark)

The application of templating methods to produce zeolite materials with hierarchical bi- or trimodal pore size distributions is reviewed with emphasis on mesoporous materials. Hierarchical zeolite materials are categorized into three distinctly different types of materials: hierarchical zeolite crystals, nanosized zeolite crystals, and supported zeolite crystals. For the pure zeolite materials in the first two categories, the additional meso- or macroporosity can be classified as being either intracrystalline or intercrystalline, whereas for supported zeolite materials, the additional porosity originates almost exclusively from the support material. The methods for introducing mesopores into zeolite materials are discussed and categorized. In general, mesopores can be templated in zeolite materials by use of solid templating, supramolecular templating, or indirect templating. In this categorization of templating methods, the nature of the interface between the zeolite crystal and the mesopore exactly when themesopore starts to form is emphasized. In solid templating, the zeolite crystal is in intimate contact with a solid material that is being removed to produce the mesoporosity. Similarly, in supramolecular templating, the zeolite crystal is in direct contact with a supramolecular assembly of organized surfactants, which is removed to generate the mesopores. On the other hand, in the indirect templating method, the interface is between the zeolite crystal and solvent molecules, or possibly a gas phase. It is shown that the available templating approaches are quite versatile, and accordingly, it is possible to produce a very wide range of hierarchical zeolite materials. The resulting zeolite materials, featuring noncrystallographic mesopores in addition to the crystallographic micropores, exhibit significantly enhanced diffusional properties in comparison with purely microporous zeolite materials. These enhanced mass transport properties have been shown in several cases to result in significantly improved catalytic properties in a range of important reactions.

Egeblad, Kresten; Christensen, Christina Hviid

2008-01-01

88

Resin conditioning facility  

Energy Technology Data Exchange (ETDEWEB)

The resin conditioning facility is designed to condition the spent ion exchange resins from the ponds water treatment units of the La Hague plant. Conditioning of the resins includes three successive steps: concentration, pretreatment and cementing. The activity fixed on resins is chiefly Co 60 activity. The facility is capable of conditioning the different types of resins. (N.C.)

Guerrand, P. [Societe Generale pour les Techniques Nouvelles (SGN), 50 - Equeurdreville (France); Dupuis, D. [Cogema la Hague, 50 - Beaumont Hague (France)

1998-07-01

89

Template Directed Synthesis and Characterization of Organic Mesoporous Polymers and their Adsorption Performance for Lysozyme  

Science.gov (United States)

Three homologous series of MCFs with diverse pore topologies have been synthesized by symbiotic interplay of TMB/P123 (R1) and TEOS/P123 (R2) weight ratios in the initial microemulsion. It was found that the MCFs synthesized at R2 greater than the conventional value suffered significant lag in the mesopore volumes and areas at low concentrations of TMB. However, when R1 is increased beyond 1.0, the difference in the pore volumes and areas became negligible. Many key findings were reported through this study. TEM images revealed that the MCFs synthesized at higher values of R2 prematurely attained larger average pore sizes accompanied with portions displaying constricted worm-like mesostructures. Such bimodal mesophases are accounted by the swelling action of excess amounts of ethanol discharged due to the hydrolysis of increased amounts of TEOS present in the microemulsion along with partial TEOS dissolution in the hydrophobic PPO cores of the TMB/P123 micelles. MCFs synthesized at highest R2 value of 4.4 exhibits unique interconnected rod-like morphologies which are usually not observed for conventional MCFs. MCF produced using R1 = 2.5 and R2 = 3.0 exhibit bimodal mesophases consisting of polyhedral nanofoam-like textures along with regular spherical pores. USAXS results indicate wall thickness as large as 11 nm for MCFs produced at R2 =4.4. These MCFs of interesting mesostructures were employed as nanoscopic templates to produce Mesocellular Phenol Formaldehyde Foams (MPFFs) using vacuum-assisted incipient wetness impregnation technique. The nanocasted MPFFs show large pore volumes up to 1.4 cm3/g, BET surface areas more than 900 m2/g and large pore diameters in the range 27--99 nm depending on the MCF scaffold used. All the MPFFs showed faithful replication of the cavity sizes of their corresponding MCF parent templates. Stunningly, trimodal MPFFs resulted from the nanocasting of MCFs with R1 > 2.2. The resulting pore sizes were attributed to the original bimodal mesophases and the tertiary pore size resulting from the dissolution of silica pore walls. The organic, biocompatible MPFFs were employed as sorbents for Lysozyme immobilization at ambient temperature and under isoelectric condition. MPFFs exhibiting loading capacities of more than 230 mg/g serve to be highly encouraging in pursuing our interests further to achieve even higher uptake through post-synthesis functionalization.

Sridhar, Manasa

90

Immobilization of spent resin with epoxy resin  

International Nuclear Information System (INIS)

immobilization of spent resin using epoxy resin has been conducted. The spent resin was mixtured with epoxy resin in variation of concentration, i.e., 30, 40, 50, 60, 70 weight percent of spent resin. The mixture were pour into the plastic tube, with a diameter of 40 mm and height of 40 mm. The density, compressive strength and leaching rate were respectively measured by quanta chrome, paul weber apparatus and gamma spectrometer. The results showed that the increasing of waste concentration would be decreased the compressive strength, and increased density by immobilized waste. The leaching rate of 137Cs from waste product was not detected in experiment (author)

91

Review: Resin Composite Filling  

Directory of Open Access Journals (Sweden)

Full Text Available The leading cause of oral pain and tooth loss is from caries and their treatment include restoration using amalgam, resin, porcelain and gold, endodontic therapy and extraction. Resin composite restorations have grown popular over the last half a century because it can take shades more similar to enamel. Here, we discuss the history and use of resin, comparison between amalgam and resin, clinical procedures involved and finishing and polishing techniques for resin restoration. Although resin composite has aesthetic advantages over amalgam, one of the major disadvantage include polymerization shrinkage and future research is needed on reaction kinetics and viscoelastic behaviour to minimize shrinkage stress.

Desmond Ng

2010-02-01

92

Adsorption of alkaloids on ordered mesoporous carbon.  

Science.gov (United States)

An ordered mesoporous carbon (OMC) adsorbent was synthesized, characterized, and evaluated for effective separation and purification of alkaloid compounds from aqueous solutions. The OMC adsorbent has a large BET specific surface area (1532.2m(2)/g), large pore volume (2.13cm(3)/g), and narrow pore diameter distribution with a median pore diameter of 4.21nm. Berberine hydrochloride, colchicine, and matrine were selected as the model compounds for evaluating the adsorption properties of the OMC adsorbent for alkaloid purification. Batch adsorption experiments of pure components in water were carried out to measure both adsorption equilibria and kinetics, and column breakthrough and desorption experiments were performed to validate the separation and regeneration efficacy of the OMC adsorbent. The adsorption equilibrium capacities of berberine hydrochloride, colchicine, and matrine on the OMC adsorbent at 0.100mg/L and 298K are 450, 600, and 480mg/g, respectively, which are more than double the adsorption capacities of these compounds on two commonly used commercial resins (HPD300 and HPD100B) at similar conditions. Adsorption equilibrium of all three alkaloids could be obtained within 120min at 298K. The dynamic adsorption capacities determined from the breakthrough experiments are within 12% of the estimated equilibrium capacities from the Langmuir isotherms; and 74.3-92.8% of the adsorbed amounts could be recovered by desorbing with a 70% alcohol solution. The adsorption isotherms are analyzed with both Langmuir and Freundlich models, the adsorption kinetic data with the pseudo-first-order and pseudo-second-order models, and the breakthrough curves with four breakthrough models. The large adsorption capacity, fast adsorption rate, and easy regeneration make the ordered mesoporous carbon a promising adsorbent for adsorption and purification of alkaloid compounds from the extracts of herbal plants. PMID:23953651

Li, Yin; Yuan, Bin; Fu, Jie; Deng, Shuguang; Lu, Xiuyang

2013-10-15

93

Mesoporous poly(melamine-formaldehyde) solid sorbent for carbon dioxide capture.  

Science.gov (United States)

Feed the pore: A highly mesoporous melamine-formaldehyde resin is synthesized through a simple, one-step polycondensation reaction by using inexpensive and abundant common industrial chemicals. The material is demonstrated to have a high surface area and a well-defined pore structure. Its high density of CO2 binding pockets with low CO2 binding energy facilitates rapid and reversible CO2 sorption. PMID:23757327

Tan, Mei Xuan; Zhang, Yugen; Ying, Jackie Y

2013-07-01

94

Asphaltene-resin association  

Energy Technology Data Exchange (ETDEWEB)

This study examined the association of resins with asphaltenes within the context of asphaltenes-as-colloidal-aggregates being peptized by surfactant-like resin species. Both solubility and phase behaviour data was presented along with scattering results to clarify questions regarding meaning of association. Questions regarding the size of resin-peptized asphaltene aggregates, clustering, phase separation and co-precipitation were discussed. The study showed that pentane resins must form a continuum, as one can continuously slide the definition of resins and asphaltenes just by choice of solvent and solvent mixtures. This paper explained this behaviour by considering the local composition in a solution of complex molecules.

Sirota, E.; Peczak, P. [ExxonMobil Research and Engineering Co., Houston, TX (United States). Corporate Strategic Research

2008-07-01

95

Mesoporous carbon as a novel drug carrier of fenofibrate for enhancement of the dissolution and oral bioavailability.  

Science.gov (United States)

The purpose of this study was to develop mesoporous carbon loaded with a poorly watersoluble drug to enhance the drug dissolution and improve the oral bioavailability. Mesoporous carbon was synthesized using Pluronic 127 triblock polymer (F127), TEOS and phenolic resins. Fenofibrate (FFB) was chosen as a model drug and loaded onto mesoporous carbon using three different loading methods involving incipient wetness impregnation, and the solvent and melting methods. The effect of the physical state and the specific surface area were investigated using nitrogen adsorption, transmission electron microscopy (TEM), powder X-ray diffraction (XRD) and differential scanning calorimetry (DSC). It was found that the physicochemical properties of the drug as well as the drug loading methods had critical effects on the drug release rate. In vitro drug release studies showed that incorporation of FFB in mesoporous carbon greatly enhanced the dissolution rate in comparison with that of the pure crystalline drug. Moreover, the oral bioavailability of the drug from mesoporous carbon was higher than that of FFB commercial capsules. Furthermore, mesoporous carbon produced no irritation of the mucosa of the gastrointestinal tract as shown by gastric mucosa irritation test. PMID:23688621

Niu, Xia; Wan, Long; Hou, Zhong; Wang, Tianyi; Sun, Changshan; Sun, Jin; Zhao, Peng; Jiang, Tongying; Wang, Siling

2013-08-16

96

Synthesis of a new functionalized mesoporous silica for determination of antimony by flow injection solid phase extracton coupled with on line hydride generation ETAAS.  

OpenAIRE

A chelating resin, [1,5 bis(di-2-pyridyl) methylene thiocarbohydrazide] bonded to mesoporous silica (DPTH-ms), has been used as a novel solid phase extractant. This resin has some advantages compared to most of other chelating adsorbents. Therefore, the aim is to develop a reliable method for determination of the aforementioned element from natural water samples by the on-line column preconcentration/HG-ETAAS using the resin DPTH-ms. With all experimental variables optimized, a linear cal...

Lo?pez, M. Mar; Siles, M. Teresa; Garci?a, Amparo; Cano, Jose? Manuel; Vereda, Elisa I.

2013-01-01

97

Determination of mercury by flow injection solid phase extraction coupled with on-line hydride generation ETAAS using as solid phase extractant a new functionalized mesoporous silica  

OpenAIRE

A chelating resin, [1,5 bis(di-2-pyridyl) methylene thiocarbohydrazide] bonded to mesoporous silica (DPTH-ms), has been used as a novel solid phase extractant. This resin has some advantages compared to most of other chelating adsorbents. Therefore, the aim is to develop a reliable method for determination of the aforementioned element from natural water samples by the on-line column preconcentration/HG-ETAAS using the resin DPTH-ms. With all experimental variables optimized, a linear cal...

Lo?pez Guerrero, Mari?a Del Mar; Siles Cordero, Mari?a Teresa; Vereda Alonso, Elisa Isabel; Garci?a Torres, Amparo; Cano Pavo?n, Jose? Manuel

2013-01-01

98

Research Update: Mesoporous sensor nanoarchitectonics  

Directory of Open Access Journals (Sweden)

Full Text Available In this short review, we have selected three main subjects: (i mesoporous materials, (ii sensing applications, and (iii the concept of nanoarchitectonics, as examples of recent hot topics in nanomaterials research. Mesoporous materials satisfy the conditions necessary not only for a wide range of applications but also for ease of production, by a variety of simple processes, which yield bulk quantities of materials without loss of their well-defined nanometric structural features. Sensing applications are of general importance because many events arise from interaction with external stimuli. In addition to these important features, nanoarchitectonics is a concept aimed at production of novel functionality of whole units according to concerted interactions within nanostructures. For the combined subject of mesoporous sensor nanoarchitectonics, we present recent examples of research in the corresponding fields categorized according to mechanism of detection including optical, electrical, and piezoelectric sensing.

Katsuhiko Ariga

2014-03-01

99

Mesoporous Silicate Materials in Sensing  

Directory of Open Access Journals (Sweden)

Full Text Available Mesoporous silicas, especially those exhibiting ordered pore systems and uniform pore diameters, have shown great potential for sensing applications in recent years. Morphological control grants them versatility in the method of deployment whether as bulk powders, monoliths, thin films, or embedded in coatings. High surface areas and pore sizes greater than 2 nm make them effective as adsorbent coatings for humidity sensors. The pore networks also provide the potential for immobilization of enzymes within the materials. Functionalization of materials by silane grafting or through cocondensation of silicate precursors can be used to provide mesoporous materials with a variety of fluorescent probes as well as surface properties that aid in selective detection of specific analytes. This review will illustrate how mesoporous silicas have been applied to sensing changes in relative humidity, changes in pH, metal cations, toxic industrial compounds, volatile organic compounds, small molecules and ions, nitroenergetic compounds, and biologically relevant molecules.

Paul T. Charles

2008-08-01

100

Aligned mesoporous architectures and devices.  

Energy Technology Data Exchange (ETDEWEB)

This is the final report for the Presidential Early Career Award for Science and Engineering - PECASE (LDRD projects 93369 and 118841) awarded to Professor Yunfeng Lu (Tulane University and University of California-Los Angeles). During the last decade, mesoporous materials with tunable periodic pores have been synthesized using surfactant liquid crystalline as templates, opening a new avenue for a wide spectrum of applications. However, the applications are somewhat limited by the unfavorabe pore orientation of these materials. Although substantial effort has been devoted to align the pore channels, fabrication of mesoporous materials with perpendicular pore channels remains challenging. This project focused on fabrication of mesoporous materials with perpendicularly aligned pore channels. We demonstrated structures for use in water purification, separation, sensors, templated synthesis, microelectronics, optics, controlled release, and highly selective catalysts.

Brinker, C. Jeffrey; Lu, Yunfeng (University of California Los Angeles, Los Angeles, CA)

2011-03-01

101

Polyvinyl chloride resin  

International Nuclear Information System (INIS)

This book contains polyvinyl chloride resin industry with present condition such as plastic industry and polyvinyl chloride in the world and Japan, manufacture of polyvinyl chloride resin ; suspension polymerization and solution polymerization, extruding, injection process, hollow molding vinyl record, vacuum forming, polymer powders process, vinyl chloride varnish, vinyl chloride latex, safety and construction on vinyl chloride. Each chapter has descriptions on of process and kinds of polyvinyl chloride resin.

102

Mesoporous materials as gas sensors.  

Science.gov (United States)

Ordered mesoporous materials have great potential in the field of gas sensing. Today various template-assisted synthesis methods facilitate the preparation of silica (SiO2) as well as numerous metal oxides with well-defined, uniform and regular pore systems. The unique nanostructural properties of such materials are particularly useful for their application as active layers in gas sensors based on various operating principles, such as capacitive, resistive, or optical sensing. This review summarizes the basic aspects of materials synthesis, discusses some structural properties relevant in gas sensing, and gives an overview of the literature on ordered mesoporous gas sensors. PMID:23232579

Wagner, Thorsten; Haffer, Stefanie; Weinberger, Christian; Klaus, Dominik; Tiemann, Michael

2013-05-01

103

Influência da composição da resina tanino-uréia-formaldeído nas propriedades físicas e macânicas de chapas aglomeradas / Influence of the composition of tannin-urea-formaldehyde resins in the in the physical and mechanicals properties of particleboard  

Scientific Electronic Library Online (English)

Full Text Available Na fabricação de aglomerados à base de madeira são utilizados adesivos sintéticos como melamina-formaldeído (MF), fenol-formaldeído (FF), uréia-formaldeído (UF), entre outros. Devido ao alto custo desses adesivos, pesquisas que visam a introdução de alterações nas suas formulações são importantes pa [...] ra a redução de custos no sistema produtivo. Desta forma, este trabalho teve como objetivo estudar a influência da adição de diferentes níveis de tanino de Acacia mearnsii em uma resina comercial à base de uréia-formaldeído nas propriedades físicas e mecânicas de chapas aglomeradas. As chapas aglomeradas foram confeccionadas com madeira de Eucalyptus urophylla. Foram avaliadas quatro composições de adesivo: T1 - 100% de resina UF (testemunha); (T2) 90% de resina UF + 10% de tanino 50%; (T3) 85% de resina UF + 15% de tanino 50% e (T4) 70% de resina UF + 30% de tanino 50%. Através dos ensaios, conclui-se que é possível adicionar tanino à resina uréia-formaldeído sem com isso prejudicar as propriedades físicas e mecânicas das chapas. Abstract in english In the production of the wood base particleboards, synthetic adhesives are used as melamina-formaldehyde (MF), phenol-formaldehyde (FF), urea-formaldehyde (UF), among others. Due to the high cost of these adhesives, researches that a seek the introduction of alterations in their formulations are imp [...] ortant for the reduction of costs in the productive system. This work had as objective verify the influence of the several levels of Acacia mearnsii tannin in a commercial resin of urea-formaldehyde an the physical and mechanical properties of the particleboard. The particleboard was produced with Eucalyptus urophylla wood. They were four treatments: T1 - 100% of resin UF (control); (T2) 90% of the resin UF + 10% of the tannin 50%; (T3) 85% of the resin UF + 15% of the tannin 50% and (T4) 70% of the resin UF + 30% of the tannin 50%. The results showed that it is possible to add tannin to the resin urea-formaldehyde without to alter the physical and mechanical properties of the boards.

Fabrício Gomes, Gonçalves; Roberto Carlos Costa, Lelis; José Tarcísio da Silva, Oliveira.

2008-08-01

104

Bioregeneration of hyper-cross-linked polymeric resin preloaded with phenol.  

Science.gov (United States)

In this study, the preliminary feasibility of bio-regeneration of a hyper-cross-linked polymeric resin NDA-802 preloaded with phenol was investigated. As compared to the abiotic experiments, phenol preloaded with NDA-802 could be effectively desorbed and biodegraded, and the bioregenerated NDA-802 could be employed for multiple use. The concentration gradient hypothesis could interpret such bioregeneration process reasonably. A slight drop in adsorption capacity of NDA-802 after bioregeneration possibly resulted from the mesopore blockage by microbial metabolic by-products. In general, bioregeneration could serve as a potential choice for the exhausted hyper-cross-linked polymeric resin in wastewater treatment. PMID:23727014

Ren, Jie; Yang, Wenlan; Hua, Ming; Pan, Bingcai; Zhang, Weiming

2013-08-01

105

Synthesis and characterization of mesoporous materials  

Science.gov (United States)

Mesoporous materials are highly porous solids with pore sizes in the range of 20 to 500 A and a narrow pore size distribution. Creating a mesoporous morphology in transition metal oxides is expected to increase the kinetics of electrochemical photoelectrochemical processes due to the improved accessibility of electrolyte to electrode. The objective of the dissertation research is to prepare functional mesoporous materials based on transition metal oxides and to determine the effects of the mesoporous structure on the resulting charge transfer, electrochromism, and optical properties. In this dissertation, mesoporous tungsten oxide and niobium oxide were synthesized by incorporating tri-block copolymer surfactant templates into the sol-gel synthesis procedure. Both mesoporous materials have surface areas in the range of 130 m2/g with a narrow pore size distribution centered at ˜45A. Their electrochromic properties were characterized and found to be strongly influenced by the mesoporous morphology. Both mesoporous systems exhibit better electrochemical and optical reversibilities than the analogous sol-gel materials (without using surfactant) and the kinetics of bleaching is substantially faster. Coloration efficiencies for the mesoporous tungsten oxide and niobium oxide films are in the range of 16--37 cm 2/C and 12--16 cm2/C, respectively. Dye sensitized solar cells (DSSC) were fabricated using mesoporous niobium oxide as electrodes. Due to the higher surface area, the mesoporous electrodes have greater dye adsorption and electrolyte penetration compared to sol-gel electrodes, which leads to better electron injection, faster dye regeneration and thus, better cell performance. The mesoporous DSSC exhibits photocurrents of 2.9 mA and fill factors of 0.61. Open circuit voltages of the mesoporous DSSC are in the range of 0.6--0.83V.

Cheng, Wei

106

Mesoporous carbon-vanadium oxide films by resol-assisted, triblock copolymer-templated cooperative self-assembly.  

Science.gov (United States)

Unlike other crystalline metal oxides amenable to templating by the combined assemblies of soft and hard chemistries (CASH) method, vanadium oxide nanostructures templated by poly(ethylene oxide-b-1,4-butadiene-b-ethylene oxide) (OBO) triblock copolymers are not preserved upon high temperature calcination in argon. Triconstituent cooperative assembly of a phenolic resin oligomer (resol) and an OBO triblock in a VOCl3 precursor solution enhances the carbon yield and can prevent breakout crystallization of the vanadia during calcination. However, the calcination environment significantly influences the observed mesoporous morphology in these composite thin films. Use of an argon atmosphere in this processing protocol leads to nearly complete loss of carbon-vanadium oxide thin film mesostructure, due to carbothermal reduction of vanadium oxide. This reduction mechanism also explains why the CASH method is not more generally successful for the fabrication of ordered mesoporous vanadia. Carbonization under a nitrogen atmosphere at temperatures up to 800 °C instead enables formation of a block copolymer-templated mesoporous structure, which apparently stems from the formation of a minor fraction of a stabilizing vanadium oxynitride. Thus, judicious selection of the inert gas for template removal is critical for the synthesis of well-defined, mesoporous vanadia-carbon composite films. This resol-assisted assembly method may generally apply to the fabrication of other mesoporous materials, wherein inorganic framework crystallization is problematic due to kinetically competitive carbothermal reduction processes. PMID:25317954

Bhaway, Sarang M; Kisslinger, Kim; Zhang, Lihua; Yager, Kevin G; Schmitt, Andrew L; Mahanthappa, Mahesh K; Karim, Alamgir; Vogt, Bryan D

2014-11-12

107

Mesoporous carbon -Cr2O3 composite as an anode material for lithium ion batteries  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous carbon-Cr2O3 (M-C-Cr2O3) composite was prepared by co-assembly of in-situ formed phenolic resin, chromium precursor, and Pluronic block copolymer under acidic conditions, followed by carbonization at 750oC under Argon. The TEM results confirmed that the Cr2O3 nanoparticles, ranging from 10 to 20 nm, were well dispersed in the matrix of mesoporous carbon. The composite exhibited an initial reversible capacity of 710 mAh g-1 and good cycling stability, which is mainly due to the synergic effects of carbons within the composites, i.e. confining the crystal growth of Cr2O3 during the high temperature treatment step and buffering the volume change of Cr2O3 during the cycling step. This composite material is a promising anode material for lithium ion batteries.

Guo, Bingkun [ORNL; Chi, Miaofang [ORNL; Sun, Xiao-Guang [ORNL; Dai, Sheng [ORNL

2012-01-01

108

Reduction of polyester resin shrinkage by means of epoxy resin  

International Nuclear Information System (INIS)

The possibility was investigated of reducing the shrinkage of unsaturated polyester resin taking place in radiation-induced curing, by the addition of epoxy resin. In order to combine chemically both resins, the epoxy component was modified by introducing unsaturated bonds via acrylamide and N-hydroxymethyloloacrylamide. A composition of 90% unsaturated polyester resin and 10% acrylamide-modified epoxy resin, filled with silica (1:1.5), showed a volume shrinkage below 2%. (author)

109

Reduction of polyester resin shrinkage by means of epoxy resin  

International Nuclear Information System (INIS)

An attempt was made to decrease the shrinkage of unsaturated polyester resin, taking place during radiation-induced curing, by the addition of epoxy resin. In order to combine chemically both resins, the epoxy component was modified with cinnamic and acrylic acids. A composition of 90 parts of polyester resin, 10 parts of epoxy resin modified with cinnamic acid, and 150 parts of a silica filler showed a volume shrinkage of 1.2%. (author)

110

Macroreticular ion exchange resins  

International Nuclear Information System (INIS)

A brief description of macrorecticular resins, their preparation and properties is given. The usual assumption that porous resins will show faster kinetic compared with gel type resins in shown to be not always true by citing example of exchange of uranyl sulfate/sulfate system. The mono sized anion exchanger Mono Q through reported to be 240 times faster than DEAE-Sepharose CL-6B for separation of biomolecules,the results with monodisperse anion exchanger (having the same polystyrene-DVB matrix as Mono Q) show that these resins are good in case of small cation eg. Na+ but give long elution tail in case of larger molecules eg. Eu-a hydroxy isobutyric acid complex due to contributed of micropores. (author)

111

Adsorption behavior mesoporous silica materials  

International Nuclear Information System (INIS)

The adsorption behaviour of mesoporous SBA-15 and its plugged analogues (PHTS) were studied in detail. The SBA-15 materials consist of a 2-D hexagonally ordered array of long interconnected pore channels with diameters, which can vary within the range of 4.6 to 30 nm. The PHTS is an analogous materials to SBA-15 containing extra microporous amorphous silica nanoparticles (plugs) within the mesopores thus creating a material with superior mechanical stability. For both types of materials, the adsorption characteristics were evaluated using linear (n-hexane and n-heptane), branched (3-methylpentane), cyclic (c-hexane) and unsaturated (1-hexene) hydrocarbons. For n-hexane, c-hexane, 3-methylpentane and n-heptane the adsorption is mainly controlled by steric effects (size and shape of the molecules), structure of the adsorbed layer and the presence and location of plugs inside the mesoporous channel system. However, the sorption of unsaturated hydrocarbons is additionally governed by the hydrophobic/hydrophilic properties of the adsorbent. Furthermore, the effect of the surface topology in SBA and PHTS on the deposition of transition metal oxides, using the molecular designed dispersion (MDD) technique, was studied by the adsorption behaviour of VO (acac)2 and dimeric TiO(acac)2. In contrast to the SBA-15, the sorption in PHTS materials was mainly controlled by the size of the adsorbate and the sorption temperature. (authors)

112

Improved conversion efficiency of amorphous Si solar cells using a mesoporous ZnO pattern.  

Science.gov (United States)

To provide a front transparent electrode for use in highly efficient hydrogenated amorphous silicon (a-Si:H) thin-film solar cells, porous flat layer and micro-patterns of zinc oxide (ZnO) nanoparticle (NP) layers were prepared through ultraviolet nanoimprint lithography (UV-NIL) and deposited on Al-doped ZnO (AZO) layers. Through this, it was found that a porous micro-pattern of ZnO NPs dispersed in resin can optimize the light-trapping pattern, with the efficiency of solar cells based on patterned or flat mesoporous ZnO layers increased by 27% and 12%, respectively. PMID:25276101

Go, Bit-Na; Kim, Yang Doo; Suk Oh, Kyoung; Kim, Chaehyun; Choi, Hak-Jong; Lee, Heon

2014-01-01

113

Improved conversion efficiency of amorphous Si solar cells using a mesoporous ZnO pattern  

Science.gov (United States)

To provide a front transparent electrode for use in highly efficient hydrogenated amorphous silicon (a-Si:H) thin-film solar cells, porous flat layer and micro-patterns of zinc oxide (ZnO) nanoparticle (NP) layers were prepared through ultraviolet nanoimprint lithography (UV-NIL) and deposited on Al-doped ZnO (AZO) layers. Through this, it was found that a porous micro-pattern of ZnO NPs dispersed in resin can optimize the light-trapping pattern, with the efficiency of solar cells based on patterned or flat mesoporous ZnO layers increased by 27% and 12%, respectively.

Go, Bit-Na; Kim, Yang Doo; suk Oh, Kyoung; Kim, Chaehyun; Choi, Hak-Jong; Lee, Heon

2014-09-01

114

Acetylene terminated matrix resins  

Science.gov (United States)

The synthesis of resins with terminal acetylene groups has provided a promising technology to yield high performance structural materials. Because these resins cure through an addition reaction, no volatile by-products are produced during the processing. The cured products have high thermal stability and good properties retention after exposure to humidity. Resins with a wide variety of different chemical structures between the terminal acetylene groups are synthesized and their mechanical properties studied. The ability of the acetylene cured polymers to give good mechanical properties is demonstrated by the resins with quinoxaline structures. Processibility of these resins can be manipulated by varying the chain length between the acetylene groups or by blending in different amounts of reactive deluents. Processing conditions similar to the state-of-the-art epoxy can be attained by using backbone structures like ether-sulfone or bis-phenol-A. The wide range of mechanical properties and processing conditions attainable by this class of resins should allow them to be used in a wide variety of applications.

Goldfarb, I. J.; Lee, Y. C.; Arnold, F. E.; Helminiak, T. E.

1985-01-01

115

40 CFR 414.50 - Applicability; description of the thermosetting resins subcategory.  

Science.gov (United States)

...Polyesters *Furan Resins Glyoxal-Urea Formaldehyde Textile Resin *Ketone-Formaldehyde Resins *Melamine Resins *Phenolic Resins *Polyacetal Resins Polyacrylamide *Polyurethane Prepolymers *Polyurethane Resins...

2010-07-01

116

Progress in DUV resins  

Science.gov (United States)

Starting from general arguments on the relation of polymer structure, transparency at 248 nm, resin hydrophilicity and resist dissolution characteristics, binder systems for novel DUV resists are presented, and the results of their lithographic evaluation are discussed. Phenolic polymers studied include homo- and copolymers of 2-, 3-, and 4- hydroxystyrenes and of their alkyl substituted derivatives for three- component systems, as well as 2- and 4-hydroxyphenylmethacrylates for use in two-component t-BOC-type resists. As an alternative nonphenolic resin, the performance of a maleimide/styrene copolymer in a two- component system is discussed.

Przybilla, Klaus J.; Roeschert, Heinz; Spiess, Walter; Eckes, Charlotte; Chatterjee, Subhankar; Khanna, Dinesh N.; Pawlowski, Georg; Dammel, Ralph R.

1991-06-01

117

Spent ion exchange resins  

International Nuclear Information System (INIS)

To achieve acceptable volume and weight reduction, before immobilization, wet oxidation of organic ion exchange resins has been studied in laboratory scale. Both cation and anion exchange resins were subjected to oxidative degradation using hydrogen peroxide. Economically wet oxidation has proved to be a promising process as for as the problem of off gas treatment and consequently the required facilities are concerned. Conversion percentages higher than 99% and 95% for cation and anion exchange respectively were reached using this technique.1 tab., 7 fig

118

Ordered mesoporous carbon coating on cordierite: Synthesis and application as an efficient adsorbent  

Energy Technology Data Exchange (ETDEWEB)

Highlight: Black-Right-Pointing-Pointer Surfactant self-assembly of ordered mesoporous carbon coating on honeycomb cordierite. Black-Right-Pointing-Pointer Carbon coating with opened, hexagonally ordered pore arrays. Black-Right-Pointing-Pointer Honeycomb adsorbents for removal of p-chlorophenol. Black-Right-Pointing-Pointer The adsorbents exhibit large processing volume, and great advantages in reusability. - Abstract: Ordered mesoporous carbon coating on the honeycomb cordierite substrate has been prepared using low-polymerized phenolic resins as carbon sources and triblock copolymer F127 as the structure directing agent via the evaporation induced self-assembly route. The high-resolution scanning electron microscopy (HRSEM), transmission electron microscopy (TEM), and nitrogen sorption techniques prove the hexagonally ordered pore arrays of carbon coating on the cordierite. The honeycomb monolith adsorbents coated by ordered mesoporous carbons are directly used without any activation, and exhibit adsorption capacities for chlorinated organic pollutants in water with 200 mg/g for p-chlorophenol and 178 mg/g for p-chloroaniline (with respect to the net carbon coating), high adsorption ratio for low-concentration pollutants, large processing volumes and reusability. More than 200 repeated times can be achieved without obvious loss in both adsorption capacity and weight.

Wan, Ying, E-mail: ywan@shnu.edu.cn [Key Laboratory of Resource Chemistry of Ministry of Education, Shanghai Key Laboratory of Rare Earth Functional Materials, Shanghai Normal University, Shanghai 200234 (China); Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China); Cui, Xiangting; Wen, Zhentao [Department of Chemistry, Shanghai Normal University, Shanghai 200234 (China)

2011-12-30

119

Surfactant-Templated Mesoporous Metal Oxide Nanowires  

Directory of Open Access Journals (Sweden)

Full Text Available We demonstrate two approaches to prepare mesoporous metal oxide nanowires by surfactant assembly and nanoconfinement via sol-gel or electrochemical deposition. For example, mesoporous Ta2O5 and zeolite nanowires are prepared by block copolymer Pluronic 123-templated sol-gel method, and mesoporous ZnO nanowires are prepared by electrodeposition in presence of anionic surfactant sodium dodecyl sulfate (SDS surfactant, in porous membranes. The morphologies of porous nanowires are studied by scanning electron microscopy (SEM and transmission electron microscopy (TEM analyses.

Stacy Baber

2010-01-01

120

Pore Narrowing of Mesoporous Silica Materials  

OpenAIRE

To use mesoporous silicas as low-k materials, the pore entrances must be really small to avoid diffusion of metals that can increase the dielectric constant of the low-k dielectric. In this paper we present a new method to narrow the pores of mesoporous materials through grafting of a cyclic-bridged organosilane precursor. As mesoporous material, the well-studied MCM-41 powder was selected to allow an easy characterization of the grafting reactions. Firstly, the successful grafting of the cyc...

Christophe Detavernier; Pascal Van Der Voort; Isabel van Driessche; Baklanov, Mikhail R.; Els De Canck; Elisabeth Levrau; Frederik Goethals

2013-01-01

121

Sonochemical reactions with mesoporous alumina.  

Science.gov (United States)

Herein, we report the sonochemical reactions with MSU-X mesoporous alumina (m-Al(2)O(3)) in aqueous solutions. Sonication (f=20 kHz, I=30 Wcm(-2), W(aq)=0.67 WmL(-1), T=36-38 degrees C, Ar) causes significant acceleration of m-Al(2)O(3) dissolution in the pH range of 4-11. Moreover, power ultrasound has a dramatic effect on the textural properties and phase composition of m-Al(2)O(3). Short-time sonication at pH = 4 leads to the formation of nanorods and nanofibers of boehmite, AlO(OH). Prolonged ultrasonic treatment causes high aspect morphology transformation to aggregated nanosheets in weakly acid solutions or plated nanocrystals in alkaline solutions. Sonochemical products in alkaline medium are composed principally from boehmite and small amounts of bayerite, Al(OH)(3). Silent hydrolysis of m-Al(2)O(3) yields boehmite at pH = 4 and bayerite at pH = 11. The effect of ultrasound on the textural properties of mesoporous alumina as well as on the transformation of nanosized bayerite to boehmite can be consistently attributed to the transient strong heating of the liquid shell surrounding the cavitation bubble which caused the chemical processes similar to those occurred during hydrothermal treatment. PMID:19211292

Chave, Tony; Nikitenko, Sergei I; Granier, Dominique; Zemb, Thomas

2009-04-01

122

Drug Loading of Mesoporous Silicon  

Science.gov (United States)

The nanostructuring of crystalline solids with low aqueous solubilities by their incorporation into mesoporous host materials is one route to improve the bioavailability of such solids. Earlier studies suggest that mesoporous Si (PSi), with pore widths in the range of 5-50 nm, is a candidate for such an approach. In this presentation, we describe efforts to load curcumin into free-standing microparticles of PSi. Curcumin is a compound extracted from turmeric root, which is an ingredient of curry. Curucmin has shown activity against selected cancer cell lines, bacteria, and other medical conditions. However, curcumin has a very low bioavailability due to its extremely low water solubility (0.6?g/mL). Incorporation of curcumin was achieved by straightforward loading of the molten solid at 185^oC. Loading experiments were performed using PSi particles of two different size ranges, 45-75 ?m and 150-250 ?m. Longer loading times and ratio of curcumin to PSi leads to a higher percentage of loaded curcumin in both PSi particle sizes (as determined by weight difference). The extent of curcumin crystallinity was assessed by x-ray diffraction (XRD). The solubility and release kinetics of loaded curcumin from the PSi was determined by extraction into water at 37^oC, with analysis using UV-VIS spectrometry.

Moffitt, Anne; Coffer, Jeff; Wang, Mengjia

2011-03-01

123

Resins for condensate polishing  

International Nuclear Information System (INIS)

Condensate polishing is, in principle, very simple and requires low TDS water, ie condensate, containing at most a few ppm of dissolved salts, gases and insoluble corrosion products, at near ambient temperatures, to be demineralised and filtered (at high linear and specific flow rates) to a quality acceptable as feedwater back to the boiler. In practice the process can be, and usually is, quite complex, and this complexity reflects the quality and quantity of treated water required, the nature of the components in the feedwater, the type and characteristics and condition of the resins employed, the design and operation of the engineering equipment (mixed beds) and the effect on treated water quality which interactions between the other variables can have. A brief review is given of the basic requirements expected from ion exchange resins used for condensate polishing together with mention of the many process features which affect the performance of the resins and influence the thinking of the resin manufacturers. Specifications are given for treated condensate in Magnox, AGR and PWR nuclear power plants. (U.K.)

124

Nontoxic Resins Advance Aerospace Manufacturing  

Science.gov (United States)

The 2008 NASA Commercial Invention of the Year, PETI-330, is a polyimide matrix resin that performs well at high temperatures and is easily processed into composites in a simple, short curing cycle. Invented by scientists at Langley Research Center, PETI-330 is now licensed to Ube Industries, based in Japan with its American headquarters in New York. In addition to being durable and lightweight, the resin is also nontoxic, which makes it safe for workers to handle. PETI-330 was created specifically for heat-resistant composites formed with resin transfer molding and resin infusion, which formerly could only be used with low temperature resin systems.

2009-01-01

125

Sample Desorption/Onization From Mesoporous Silica  

Science.gov (United States)

Mesoporous silica is shown to be a sample holder for laser desorption/ionization of mass spectrometry. Supported mesoporous silica was prepared by coating an ethanolic silicate solution having a removable surfactant onto a substrate to produce a self-assembled, ordered, nanocomposite silica thin film. The surfactant was chosen to provide a desired pore size between about 1 nanometer diameter and 50 nanometers diameter. Removal of the surfactant resulted in a mesoporous silica thin film on the substrate. Samples having a molecular weight below 1000, such as C.sub.60 and tryptophan, were adsorbed onto and into the mesoporous silica thin film sample holder and analyzed using laser desorption/ionization mass spectrometry.

Iyer, Srinivas (Los Alamos, NM); Dattelbaum, Andrew M. (Los Alamos, NM)

2005-10-25

126

Mesoporous silica nanoreactors for highly efficient proteolysis.  

Science.gov (United States)

Protein digestion inside the nanoreactor channels of mesoporous silica (SBA-15) is reported, and evaluated by using peptide-mass mapping. Both proteases and substrates were efficiently captured within these biocompatible nanoreactors. After 10 minutes, the mass spectrum of the protein digests released from the mesoporous-silica-based nanoreactors revealed the presence of eight peptides covering 58% of the protein sequence with an intense signal (signal/noise ratio > 70). In comparison, the conventional overnight in-solution digestion of proteins under otherwise identical conditions generated only three peptides (27% sequence coverage). We propose that this order-of-magnitude increase in the proteolytic reaction rate is mainly attributed to two factors: substrate enrichment within mesoporous silica channels and enzyme immobilization. The surface properties and macrostructure of the mesoporous silica were studied to reveal their significant influence on proteolytic reactions. PMID:16001450

Fan, Jie; Shui, Wenqing; Yang, Pengyuan; Wang, Xiaoyan; Xu, Yunmin; Wang, Honghai; Chen, Xian; Zhao, Dongyuan

2005-09-01

127

Effect of seawater salinity on pore-size distribution on a poly(styrene)-based HP20 resin and its adsorption of diarrhetic shellfish toxins.  

Science.gov (United States)

In the present study, okadaic acid (OA) and dinophysistoxin-1 (DTX1) were spiked into artificial seawater at low, medium and high estuarine salinities (9‰, 13.5‰ and 27‰). Passive samplers (HP20 resin) used for solid phase adsorption toxin tracking (SPATT) technology were exposed in these seawaters for 12-h periods. Adsorption curves well fitted a pseudo-secondary kinetics model. The highest initial sorption rates of both toxins occurred in the seawater of medium salinity, followed by seawater of low and high estuarine salinity. Pore volumes of micropores (<2 nm) and small mesopores (2 nmresin decreased after adsorption of toxins in seawater at high and low salinity but not in seawater at medium salinity, which demonstrated that the toxin molecules entered into micropores and mesopores (below 10nm in size) in seawaters of high and low salinity. More toxin or other matrix agglomerates were displayed on the surface of resin deployed in the seawater of medium salinity. Taking into consideration the pore-size distribution and surface images, it appears that intra-particle diffusion governs toxin adsorption in seawater at high salinity while film diffusion mainly controls the adsorption process in seawater at medium salinity. This is the first study to confirm that molecules of OA and DTX1 are able to enter into micropores (<2nm) and small mesopores (2-10nm) of HP20 resin in estuarine seawater with high salinity (?27‰). PMID:25464996

Fan, Lin; Sun, Geng; Qiu, Jiangbing; Ma, Qimin; Hess, Philipp; Li, Aifeng

2014-12-19

128

Flame Retardant Epoxy Resins  

Science.gov (United States)

As part of a program to develop fire resistant exterior composite structures for future subsonic commercial aircraft, flame retardant epoxy resins are under investigation. Epoxies and their curing agents (aromatic diamines) containing phosphorus were synthesized and used to prepare epoxy formulations. Phosphorus was incorporated within the backbone of the epoxy resin and not used as an additive. The resulting cured epoxies were characterized by thermogravimetric analysis, propane torch test, elemental analysis and microscale combustion calorimetry. Several formulations showed excellent flame retardation with phosphorous contents as low as 1.5% by weight. The fracture toughness of plaques of several cured formulations was determined on single-edge notched bend specimens. The chemistry and properties of these new epoxy formulations are discussed.

Thompson, C. M.; Smith, J. G., Jr.; Connell, J. W.; Hergenrother, P. M.; Lyon, R. E.

2004-01-01

129

Bismaleimide Copolymer Matrix Resins  

Science.gov (United States)

Graphite composites, prepared from 1:1 copolymer of two new bismaleimides based on N,N'-m-phenylene-bis(m-amino-benzamide) structure have mechanical properties superior to those prepared from other bismaleimide-type resins. New heat-resistant composites replace metal in some structural applications. Monomers used to form copolymers with superior mechanical properties prepared by reaction of MMAB with maleic or citraconic anhydride.

Parker, John A.; Heimbuch, Alvin H.; Hsu, Ming-Ta S.; Chen, Timothy S.

1987-01-01

130

System for removing contaminants from plastic resin  

Science.gov (United States)

A resin recycling system that produces essentially contaminant-free synthetic resin material in an environmentally safe and economical manner. The system includes receiving the resin in container form. A grinder grinds the containers into resin particles. The particles are exposed to a solvent in one or more solvent wash vessels, the solvent contacting the resin particles and substantially removing contaminants on the resin particles. A separator is used to separate the resin particles and the solvent. The resin particles are then placed in solvent removing element where they are exposed to a solvent removing agent which removes any residual solvent remaining on the resin particles after separation.

Bohnert, George W. (Harrisonville, MO); Hand, Thomas E. (Lee's Summit, MO); DeLaurentiis, Gary M. (Jamestown, CA)

2010-11-23

131

Influence of uron resins on the performance of UF resins as adhesives for plywood  

OpenAIRE

Uron resin, a kind of urea-formaldehyde (UF) resin containing much more uron structure, were prepared. Several modified UF resins were obtained from mixing uron resins with normal UF resins as well as synthesizing UF resin with uron resin as raw material. This work demonstrated that the introducing of the uron structure reduced free formaldehyde content of UF resin and formaldehyde emission levels in bonded plywood panels significantly, the former were reduced by 76% and 84% in the latter. Th...

Wei Gao; Jianzhang Li,

2012-01-01

132

Vitrification of ion exchange resins  

Science.gov (United States)

The present invention relates to vitrification of ion exchange resins that have become loaded with hazardous or radioactive wastes, in a way that produces a homogenous and durable waste form and reduces the disposal volume of the resin. The methods of the present invention involve directly adding borosilicate glass formers and an oxidizer to the ion exchange resin and heating the mixture at sufficient temperature to produce homogeneous glass.

Cicero-Herman, Connie A. (Aiken, SC); Workman, Rhonda Jackson (North Augusta, SC)

2001-01-01

133

Powder Solidifyers of Epoxy Resins  

International Science & Technology Center (ISTC)

Selection and Investigation of New Powder Metallocomplex Agents as Solidifyer of Epoxy Resins for Refinement of Technological Processes During Manufacturing Electrical Insuletion of Big Electrical Engines

134

Resin regeneration device for condensate desalter  

International Nuclear Information System (INIS)

The present invention provides a resin regeneration device for a condensate desalter of a nuclear power plant. Namely, both anionic and cationic exchange resins are supplied in a mixed state from a forwarding water desalting tower to an anionic resin regeneration tower. In the anionic resin generation tower, the resin is once separated to an anionic exchange region layer, a mixed resin layer and an cationic exchange resin layer in this order from the upper portion by water injected from a stirring water injection tube disposed at the bottom. Then, water is injected from a developing water injection tube disposed at the lower portion of the mixed resin layer to develop the cationic exchange resin layer and the mixed resin layer to the upper portion of the cationic resin regeneration tower. Subsequently, the amount of the injection of the developing water is reduced to such a flow rate that only the anionic exchange resin is precipitated. Then, a cationic exchange resin layer is formed at the upper portion and an anion exchange resin layer is formed at the lower portion of the developing water injection tube of the cationic resin regeneration tower. The anionic exchange resin is transferred to the anionic exchange resin regeneration tower in this state. According to the present invention, the mixed resin layer can be separated to anionic and cationic exchange resins easily and reliably. (I.S.)

135

Nanostructured Mesoporous Silicas for Bone Tissue Regeneration  

Directory of Open Access Journals (Sweden)

Full Text Available The research on the development of new biomaterials that promote bone tissue regeneration is receiving great interest by the biomedical scientific community. Recent advances in nanotechnology have allowed the design of materials with nanostructure similar to that of natural bone. These materials can promote new bone formation by inducing the formation of nanocrystalline apatites analogous to the mineral phase of natural bone onto their surfaces, i.e. they are bioactive. They also stimulate osteoblast proliferation and differentiation and, therefore, accelerate the healing processes. Silica-based ordered mesoporous materials are excellent candidates to be used as third generation bioceramics that enable the adsorption and local control release of biological active agents that promote bone regeneration. This local delivery capability together with the bioactive behavior of mesoporous silicas opens up promising expectations in the bioclinical field. In this review, the last advances in nanochemistry aimed at designing and tailoring the chemical and textural properties of mesoporous silicas for biomedical applications are described. The recent developed strategies to synthesize bioactive glasses with ordered mesopore arrangements are also summarized. Finally, a deep discussion about the influence of the textural parameters and organic modification of mesoporous silicas on molecules adsorption and controlled release is performed.

María Vallet-Regí

2008-11-01

136

Corrosion behavior of mesoporous transition metal nitrides  

International Nuclear Information System (INIS)

Transition metal nitrides (TMN) have many desirable characteristics such as high hardness and good thermal stability under reducing conditions. This work reports an initial survey of the chemical stability of mesoporous TMNs (TM=Nb, V, Cr and Ti) in water at 80 °C at neutral, acidic and alkaline pH. The mesoporous TMNs had specific surface areas of 25–60 m2/g with average pore sizes ranging from 10 to 50 nm. The high surface areas of these materials enhance the rate of corrosion per unit mass over that of a bulk material, making detection of corrosion much easier. The products were characterized by Rietveld refinement of powder X-ray diffraction (PXRD) patterns and by scanning electron microscopy (SEM). Several nitrides have corrosion rates that are, within error, not distinguishable from zero (±1 Å/day). Of the nitrides examined, CrN appears to be the most corrosion resistant under acidic conditions. None of the nitrides studied are corrosion resistant under alkaline conditions. - Graphical abstract: Corrosion behavior of mesoporous transition metal nitrides (TM=Nb, V, Cr and Ti) in acidic and alkaline solutions at 80 °C for 2 weeks. Display Omitted - highlights: • Corrosion rates of mesoporous transition metal nitrides in aqueous solution is reported. • The mesoporous TMNs had surface areas of 25–60 m2/g. • CrN is the most corrosion resistant under the conditions studied

137

Molecular sieve behaviour of carbon aerogels and xerogels prepared from phloroglucinol-phenol-formaldehyde polymerization.  

Czech Academy of Sciences Publication Activity Database

Biarritz : SARL VACANCES SUD TERRES BASQUES, 2009, ID 153. [Carbon 09. Biarritz (FR), 14.06.2009-19.06.2009] Institutional research plan: CEZ:AV0Z40400503 Keywords : polymerization * molecular sieves * carbon aerogels Subject RIV: CF - Physical ; Theoretical Chemistry

Jirglová, Hana; Pérez-Cadenas, A. F.; Hódar, F. J. M.

138

Synthesis and Properties of Phloroglucinol-Phenol-Formaldehyde Carbon Aerogels and Xerogels.  

Czech Academy of Sciences Publication Activity Database

Ro?. 25, ?. 4 (2009), s. 2461-2466. ISSN 0743-7463 Institutional research plan: CEZ:AV0Z40400503 Keywords : organic aerogels * immersion calorimetry * activated carbon Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.898, year: 2009

Jirglová, Hana; Pérez-Cadenas, A. F.; Maldonado-Hódar, F. J.

2009-01-01

139

Mesoporous Silica and Composite Nanostructures for Theranostics  

Directory of Open Access Journals (Sweden)

Full Text Available We discus methods for fabrication of silica and composite nanoparticles, which can be used in various biomedical applications. The most promising types of such nanostructures are hollow silica nanosheres, silica coated plasmon-resonant nanoparticles (gold nanorods and gold-silver nanocages and nanorattles. Mesoporous silica shell can be doped by desirable targeting molecules. Here we present the results of formation of nanocomposites composed of gold nanorods and double-layer silica shell. The secondary mesoporous silica shell is doped with a photosensitizer (hematoporphyrine in our case. We demonstate some of promising theranostics applications of these nanocomposites for bioimaging and in vivo therapy of tumors.

Khlebtsov B.N.

2013-09-01

140

Orientation specific deposition of mesoporous particles  

Directory of Open Access Journals (Sweden)

Full Text Available We present a protocol for a facile orientation specific deposition of plate-like mesoporous SBA-15 silica particles onto a surface (mesopores oriented normal to surface. A drop of an aqueous dispersion of particles is placed on the surface and water vaporizes under controlled relative humidity. Three requirements are essential for uniform coverage: particle dispersion should not contain aggregates, a weak attraction between particles and surface is needed, and evaporation rate should be low. Aggregates are removed by stirring/sonication. Weak attraction is realized by introducing cationic groups to the surface. Insight into the mechanisms of the so-called coffee stain effect is also provided.

Tomas Kjellman

2014-11-01

141

Orientation specific deposition of mesoporous particles  

Science.gov (United States)

We present a protocol for a facile orientation specific deposition of plate-like mesoporous SBA-15 silica particles onto a surface (mesopores oriented normal to surface). A drop of an aqueous dispersion of particles is placed on the surface and water vaporizes under controlled relative humidity. Three requirements are essential for uniform coverage: particle dispersion should not contain aggregates, a weak attraction between particles and surface is needed, and evaporation rate should be low. Aggregates are removed by stirring/sonication. Weak attraction is realized by introducing cationic groups to the surface. Insight into the mechanisms of the so-called coffee stain effect is also provided.

Kjellman, Tomas; Bodén, Niklas; Wennerström, Hâkan; Edler, Karen J.; Alfredsson, Viveka

2014-11-01

142

Location of laccase in ordered mesoporous materials  

Energy Technology Data Exchange (ETDEWEB)

The functionalization with amine groups was developed on the SBA-15, and its effect in the laccase immobilization was compared with that of a Periodic Mesoporous Aminosilica. A method to encapsulate the laccase in situ has now been developed. In this work, spherical aberration (C{sub s}) corrected scanning transmission electron microscopy combined with high angle annular dark field detector and electron energy loss spectroscopy were applied to identify the exact location of the enzyme in the matrix formed by the ordered mesoporous solids.

Mayoral, Álvaro [Laboratorio de Microscopias Avanzadas, Instituto de Nanociencia de Aragon, Universidad de Zaragoza, Edificio I - D, Mariano Esquillor, 50018 Zaragoza (Spain); Gascón, Victoria; Blanco, Rosa M.; Márquez-Álvarez, Carlos; Díaz, Isabel, E-mail: idiaz@icp.csic.es [Instituto de Catálisis y Petroleoquímica, CSIC, c/Marie Curie 2, 28049 Madrid (Spain)

2014-11-01

143

Recovery of silica from electronic waste for the synthesis of cubic MCM-48 and its application in preparing ordered mesoporous carbon molecular sieves using a green approach  

Energy Technology Data Exchange (ETDEWEB)

The electronics industry is one of the world's fastest growing manufacturing industries. However, e-waste has become a serious pollution problem. This study reports the recovery of e-waste for preparing valuable MCM-48 and ordered mesoporous carbon for the first time. Specifically, this study adopts an alkali-extracted method to obtain sodium silicate precursors from electronic packaging resin ash. The influence of synthesis variables such as gelation pH, neutral/cationic surfactant ratio, hydrothermal treatment temperature, and calcination temperature on the mesophase of MCM-48 materials is investigated. Experimental results confirm that well-ordered cubic MCM-48 materials were synthesized in strongly acidic and strongly basic media. The resulting mesoporous silica had a high surface area of 1,317 m{sup 2}/g, mean pore size of about 3.0 nm, and a high purity of 99.87 wt%. Ordered mesoporous carbon with high surface area (1,715 m{sup 2}/g) and uniform pore size of CMK-1 type was successfully prepared by impregnating MCM-48 template using the resin waste. The carbon structure was sensitive to the sulfuric acid concentration and carbonization temperature. Converting e-waste into MCM-48 materials not only eliminates the disposal problem of e-waste, but also transforms industrial waste into a useful nanomaterial.

Liou, Tzong-Horng, E-mail: thliou@mail.mcut.edu.tw [Ming Chi University of Technology, Department of Chemical Engineering, Taiwan (China)

2012-07-15

144

Large-Scale Roll-to-Roll Fabrication of Ordered Mesoporous Materials using Resol-Assisted Cooperative Assembly.  

Science.gov (United States)

Roll-to-roll (R2R) processing enables the rapid fabrication of large-area sheets of cooperatively assembled materials for production of mesoporous materials. Evaporation induced self-assembly of a nonionic surfactant (Pluronic F127) with sol-gel precursors and phenolic resin oligomers (resol) produce highly ordered mesostructures for a variety of chemistries including silica, titania, and tin oxide. The cast thick (>200 ?m) film can be easily delaminated from the carrier substrate (polyethylene terephthalate, PET) after cross-linking the resol to produce meter-long self-assembled sheets. The surface areas of these mesoporous materials range from 240 m(2)/g to >1650 m(2)/g with these areas for each material comparing favorably with prior reports in the literature. These R2R methods provide a facile route to the scalable production of kilograms of a wide variety of ordered mesoporous materials that have shown potential for a wide variety of applications with small-batch syntheses. PMID:25635350

Qiang, Zhe; Guo, Yuanhao; Liu, Hao; Cheng, Stephen Z D; Cakmak, Miko; Cavicchi, Kevin A; Vogt, Bryan D

2015-02-25

145

Preparation and characterization of multifunctional magnetic mesoporous calcium silicate materials  

International Nuclear Information System (INIS)

We have prepared multifunctional magnetic mesoporous Fe–CaSiO3 materials using triblock copolymer (P123) as a structure-directing agent. The effects of Fe substitution on the mesoporous structure, in vitro bioactivity, magnetic heating ability and drug delivery property of mesoporous CaSiO3 materials were investigated. Mesoporous Fe–CaSiO3 materials had similar mesoporous channels (5–6 nm) with different Fe substitution. When 5 and 10% Fe were substituted for Ca in mesoporous CaSiO3 materials, mesoporous Fe–CaSiO3 materials still showed good apatite-formation ability and had no cytotoxic effect on osteoblast-like MC3T3-E1 cells evaluated by the elution cell culture assay. On the other hand, mesoporous Fe–CaSiO3 materials could generate heat to raise the temperature of the surrounding environment in an alternating magnetic field due to their superparamagnetic property. When we use gentamicin (GS) as a model drug, mesoporous Fe–CaSiO3 materials release GS in a sustained manner. Therefore, magnetic mesoporous Fe–CaSiO3 materials would be a promising multifunctional platform with bone regeneration, local drug delivery and magnetic hyperthermia. (paper)

146

Periodic Mesoporous Organosilica Functionalized with Sulfonic Acid Groups as Acid Catalyst for Glycerol Acetylation  

Directory of Open Access Journals (Sweden)

Full Text Available A Periodic Mesoporous Organosilica (PMO functionalized with sulfonic acid groups has been successfully synthesized via a sequence of post-synthetic modification steps of a trans-ethenylene bridged PMO material. The double bond is functionalized via a bromination and subsequent substitution obtaining a thiol functionality. This is followed by an oxidation towards a sulfonic acid group. After full characterization, the solid acid catalyst is used in the acetylation of glycerol. The catalytic reactivity and reusability of the sulfonic acid modified PMO material is investigated. The catalyst showed a catalytic activity and kinetics that are comparable with the commercially available resin, Amberlyst-15, and furthermore our catalyst can be recycled for several subsequent catalytic runs and retains its catalytic activity.

Pascal Van Der Voort

2013-08-01

147

Chromatography resin support  

Science.gov (United States)

An apparatus and method of using an improved chromatography resin support is disclosed. The chromatography support platform is provided by a stainless steel hollow cylinder adapted for being inserted into a chromatography column. An exterior wall of the stainless steel cylinder defines a groove for carrying therein an "O"-ring. The upper surface of the stainless steel column is covered by a fine stainless steel mesh welded to the edges of the stainless steel cylinder. When placed upon a receiving ledge defined within a chromatography column, the "O"-ring provides a fluid tight seal with the inner edge wall of the chromatography cylinder. The stainless steel mesh supports the chromatography matrix and provides a back flushable support which is economical and simple to construct.

Dobos, James G. (North Augusta, SC)

2002-01-01

148

Reduction of polyester resin shrinkage by means of epoxy resin—I. Epoxy resin modified with acids  

Science.gov (United States)

An attempt was made to decrease the shrinkage of unsaturated polyester resin, taking place during radiation-induced curing, by the addition of epoxy resin. In order to combine chemically both resins, the epoxy component was modified with cinnamic and acrylic acids. A composition of 90 parts of polyesster resin, 10 parts of epoxy resin modified with cinnamic acid, and 150 parts of a silica filler showed a volume shrinkage of 1.2%.

Pietrzak, M.; Brzostowski, A.

149

Flammability screening tests of resins  

Science.gov (United States)

Selected flammability characteristics of glass cloth laminates of thermosetting resins are evaluated. A protocol for the evaluation of the flammability hazards presented by glass cloth laminates of thermosetting resins and the usefulness of that protocol with two laminates are presented. The glass laminates of an epoxy resin, M-751 are evaluated for: (1) determination of smoke generation from the laminates; (2) analysis of products of oxidative degradation of the laminates; (3) determination of minimum oxygen necessary to maintain flaming oxidation; (4) evaluation of toxicological hazards.

Arhart, R. W.; Farrar, D. G.; Hughes, B. M.

1979-01-01

150

Prototype of low thermal expansion materials: fabrication of mesoporous silica/polymer composites with densely filled polymer inside mesopore space.  

Science.gov (United States)

A prototype of novel low thermal expansion materials using mesoporous silica particles is demonstrated. Mesoporous silica/polymer composites with densely filled polymer inside the mesopore space are fabricated by mechanically mixing both organically modified mesoporous silica and epoxy polymer. The mesopores are easily penetrated by polymers as a result of the capillary force during the mechanical composite processing. Furthermore, we propose a new model of polymer mobility restriction using mesoporous silica with a large pore space. The robust inorganic frameworks covering the polymer effectively restrict the polymer mobility against thermal energy. As a result, the degree of total thermal expansion of the composites is drastically decreased. From the mass-normalized thermal mechanical analysis (TMA) charts of various composites with different amounts of mesoporous silica particles, it is observed that the coefficient of thermal expansion (CTE) values gradually increase with an increase of the polymer amount outside the mesopores. It is proven that the CTE values in the range over the glass-transition temperatures (T(g)) are perfectly proportional to the outside polymer amounts. Importantly, the Y-intercept of the relation equation obtained by a least-square method is the CTE value and is almost zero. This means that thermal expansion does not occur if no polymers are outside the mesopores. Through such a quantative discussion, we clarify that only the outside polymer affects the thermal expansion of the composites, that is, the embedded polymers inside the mesopores do not expand at all during the thermal treatment. PMID:20665649

Kiba, Shosuke; Suzuki, Norihiro; Okawauchi, Yoshinori; Yamauchi, Yusuke

2010-09-01

151

Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery  

Science.gov (United States)

The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N 2 adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation ft= ktn was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties.

Gao, Lin; Sun, Jihong; Li, Yuzhen

2011-08-01

152

Bending characteristics of resin concretes  

Scientific Electronic Library Online (English)

Full Text Available In this research work the influence of composition and curing conditions in bending strength of polyester and epoxy concrete is analyzed. Various mixtures of resin and aggregates were considered in view of an optimal combination. The Taguchi methodology was applied in order to reduce the number of t [...] ests, and in order to evaluate the influence of various parameters in concrete properties. This methodology is very useful for the planning of experiments. Test results, analyzed by this methodology, shown that the most significant factors affecting bending strength properties of resin concretes are the type of resin, resin content and charge content. An optimal formulation leading to a maximum bending strength was achieved in terms of material parameters.

Maria Cristina Santos, Ribeiro; Cassilda Maria Lopes, Tavares; Miguel, Figueiredo; António Joaquim Mendes, Ferreira; António Augusto, Fernandes.

2003-06-01

153

Bending characteristics of resin concretes  

Directory of Open Access Journals (Sweden)

Full Text Available In this research work the influence of composition and curing conditions in bending strength of polyester and epoxy concrete is analyzed. Various mixtures of resin and aggregates were considered in view of an optimal combination. The Taguchi methodology was applied in order to reduce the number of tests, and in order to evaluate the influence of various parameters in concrete properties. This methodology is very useful for the planning of experiments. Test results, analyzed by this methodology, shown that the most significant factors affecting bending strength properties of resin concretes are the type of resin, resin content and charge content. An optimal formulation leading to a maximum bending strength was achieved in terms of material parameters.

Ribeiro Maria Cristina Santos

2003-01-01

154

Epoxy hydantoins as matrix resins  

Science.gov (United States)

Tensile strength and fracture toughness of castings of the hydantoin resins cured with methylenedianiline are significantly higher than MY 720 control castings. Water absorption of an ethyl, amyl hydantoin formulation is 2.1 percent at equilibrium and Tg's are about 160 C, approximately 15 deg below the final cure temperature. Two series of urethane and ester-extended hydantoin epoxy resins were synthesized to determine the effect of crosslink density and functional groups on properties. Castings cured with methylenedianiline or with hexahydrophthalic anhydride were made from these compounds and evaluated. The glass transition temperatures, tensile strengths and moduli, and fracture toughness values were all much lower than that of the simple hydantoin epoxy resins. Using a methylene bishydantoin epoxy with a more rigid structure gave brittle, low-energy fractures, while a more flexible, ethoxy-extended hydantoin epoxy resin gave a very low Tg.

Weiss, J.

1983-01-01

155

Liquid monobenzoxazine based resin system  

Energy Technology Data Exchange (ETDEWEB)

The present invention provides a liquid resin system including a liquid monobenzoxazine monomer and a non-glycidyl epoxy compound, wherein the weight ratio of the monobenzoxazine monomer to the non-glycidyl epoxy compound is in a range of about 25:75 to about 60:40. The liquid resin system exhibits a low viscosity and exceptional stability over an extended period of time making its use in a variety of composite manufacturing methods highly advantageous.

Tietze, Roger; Nguyen, Yen-Loan; Bryant, Mark

2014-10-07

156

Surface functionalized mesoporous material and method of making same  

Science.gov (United States)

According to the present invention, an organized assembly of functional molecules with specific interfacial functionality (functional group(s)) is attached to available surfaces including within mesopores of a mesoporous material. The method of the present invention avoids the standard base soak that would digest the walls between the mesopores by boiling the mesoporous material in water for surface preparation then removing all but one or two layers of water molecules on the internal surface of a pore. Suitable functional molecule precursor is then applied to permeate the hydrated pores and the precursor then undergoes condensation to form the functional molecules on the interior surface(s) of the pore(s).

Feng, Xiangdong (West Richland, WA) [West Richland, WA; Liu, Jun (West Richland, WA) [West Richland, WA; Fryxell, Glen E. (Kennewick, WA) [Kennewick, WA

2001-12-04

157

Metal ion adsorption using polyamine-functionalized mesoporous materials prepared from bromopropyl-functionalized mesoporous silica  

International Nuclear Information System (INIS)

Mesoporous silicas carrying di-, tri-, or penta-amine functional groups were prepared by prior functionalization of a mesoporous silica with bromopropyl-functional groups followed by nucleophilic displacement of the bromine atoms by ethylenediamine, diethylenetriamine, or tetraethylenepentamine, respectively. A synthetic method was developed that gave a starting material with very high surface coverage by the 3-brompropyl groups. Batch tests were conducted to investigate the capabilities of the prepared adsorbents for the removal of copper, zinc, and cadmium from aqueous solutions. The metal adsorption capacities for these metals were determined as a function of the polyamine group used and the total nitrogen content. The tendency to chemisorb divalent metal ions was found to follow the order: Cu2+ > Zn2+ > Cd2+. It was found that the ethylenediamine derivative unexpectedly exhibited the highest capacities. The metal sorption by the ethylenediamine functionalized silica was found to follow first order kinetics with rate constants for Cu2+, Zn2+ and Cd2+ uptake of 0.028, 0.019, and 0.014 min-1, respectively. The substituted mesoporous silicas showed high resistance to leaching of the grafted polyamine groups. Copper ions that were adsorbed at the surface of the mesoporous silicas can be recovered by washing with an aqueous solution of 1.0 M HNO3. The activities of the recovered mesosub>. The activities of the recovered mesoporous silicas were between 80 and 90% of the original materials.

158

Maleimide Functionalized Siloxane Resins  

Energy Technology Data Exchange (ETDEWEB)

Polyorganosiloxanes are a commercially important class of compounds. They exhibit many important properties, including very low glass transition temperatures, making them useful over a wide temperature range. In practice, the polysiloxane polymer is often mixed with a filler material to help improve its mechanical properties. An alternative method for increasing polymer mechanical strength is through the incorporation of certain substituents on the polymer backbone. Hard substituents such as carbonates and imides generally result in improved mechanical properties of polysiloxanes. In this paper, we present the preparation of novel polysiloxane resins modified with hard maleimide substituents. Protected ethoxysilyl-substituted propyl-maleimides were prepared. The maleimide substituent was protected with a furanyl group and the monomer polymerized under aqueous acidic conditions. At elevated temperatures (>120 C), the polymer undergoes retro Diels-Alder reaction with release of foran (Equation 1). The deprotected polymer can then be selectively crosslinked by a forward Diels-Alder reaction (in the presence of a co-reactant having two or more dime functionalities).

Loy, D.A.; Shaltout, R.M.

1999-04-01

159

Ion exchange resin reproducing method and equipment  

International Nuclear Information System (INIS)

Purpose: To reduce volume of radioactive liquid wastes generated by reproducing the ion exchange resin. Constitution: A pair of ion exchange membranes are placed facing with each other between the anode and the cathode installed in an electrolytic cell which is filled with the aqueous solution of regenerative agent. By using such a device, the spent ion exchange resin is regenerated. The ion exchange resin to be treated is placed in between the aforementioned ion exchange membranes, and then electrolytic dialysis is made by flowing direct current from the electrode. When the ion exchange resin to be regenerated is the cation resin, the cation resin is used as the ion exchange membrane, and sulfuric acid is used as the regenerative agent. Where the anion resin is the ion exchange resin to be generated, the anion resin is used as the ion exchange membrane, and caustic soda is used as the regenerative agent. (Ikeda, J.)

160

Curing of phenylethynl terminated resins  

International Nuclear Information System (INIS)

Full text: The curing of two phenylethynyl terminated composite resins was investigated under thermal and ?-irradiation conditions. The resins, PETI5A and DFB/BPF have been specially developed by NASA for high temperature aerospace applications, and as such have been synthesised with a high degree of aromaticity and hence lack of aliphatic protons. The thermal curing occurs via the thermal decomposition of the resin to form radicals which initiate the addition polymerisation which proceeds through the ethynyl units. The decomposition processes at the cure temperature of 360 deg C lead to the formation of a very dark coloured resin. The radiation cured resin was significantly lighter in colour, indicating less degradation of the resin. In order to reduce the degree of thermal decomposition during polymerisation, ?- radiation induced cure was attempted at 300 deg C. The loss of ethynyl bonds was monitored for both the thermal and radiation induced curing with FT-Raman Spectroscopy and the formation of a polymer network was observed using Differential Scanning Calorimetry (DSC). The maximum Glass Transition Temperatures (Tg) for the resins was found to be 245 ± 2 deg C for DFB/BPF in 60 minutes and 360 ± 2 deg C for PETI5A in 100 minutes for thermal cure at 360 deg C. Similar values were observed after ?-irradiation to doses of approximately 40 kGy for DFB/BPF and 80 kGy for PETI5A when irradiated at 300 deg C. Thermogravimetric Analysis (TGA) shows us that the thermal decomposition process is 100 times less apparent at 300 deg C than at 360 deg C

161

Disposal of bead ion exchange resin wastes  

International Nuclear Information System (INIS)

Bead ion exchange resin wastes are disposed of by a process which involves spray-drying a bead ion exchange resin waste in order to remove substantially all of the water present in such waste, including the water on the surface of the ion exchange resin beads and the water inside the ion exchange resin beads. The resulting dried ion exchange resin beads can then be solidified in a suitable solid matrix-forming material, such as a polymer, which solidifies to contain the dried ion exchange resin beads in a solid monolith suitable for disposal by burial or other conventional means

162

Investigation of mesoporous structures for thermoelectric applications  

International Nuclear Information System (INIS)

Mesoporous silicon is an attractive material for thermoelectric application. For pore wall thicknesses around <100 nm, phonons can not penetrate the porous layer while electrons still can, due to there smaller mean free path length. The resulting good electrical and bad thermal conductivity is a premise for efficient thermoelectric devices. This paper presents results regarding homogeneity, high porosity, and optimal pore wall thicknesses for porous silicon based thermoelectric devices.

163

Mesoporous Silica from Rice Husk Ash  

OpenAIRE

Mesoporous silica is used as a raw material in several areas: in preparation of catalysts, in inks, as a concrete hardening accelerator, as a component of detergents and soaps, as a refractory constituent etc. Sodium silicate is produced by reacting rice hull ash (RHA) with aqueous NaOH and silica is precipitated from the sodium silicate by acidification. In the present work, conversion of about 90% of silica contained in RHA into sodium silicate was achieved in an open system at temperatures...

Shelke, V. R.; Bhagade, S. S.; Mandavgane, S. A.

2010-01-01

164

Mesoporous Silica from Rice Husk Ash  

Directory of Open Access Journals (Sweden)

Full Text Available Mesoporous silica is used as a raw material in several areas: in preparation of catalysts, in inks, as a concrete hardening accelerator, as a component of detergents and soaps, as a refractory constituent etc. Sodium silicate is produced by reacting rice hull ash (RHA with aqueous NaOH and silica is precipitated from the sodium silicate by acidification. In the present work, conversion of about 90% of silica contained in RHA into sodium silicate was achieved in an open system at temperatures of about 100 °C. The results showed that silica obtained from RHA is mesoporous, has a large surface area and small particle size. Rice Husk is usually mixed with coal and this mixture is used for firing boilers. The RHA therefore, usually contains carbon particles. Activated carbon embedded on silica has been prepared using the carbon already present in RHA. This carbon shows good adsorption capacity. ©2010 BCREC UNDIP. All rights reserved(Received: 25th April 2010, Revised: 17th June 2010, Accepted: 24th June 2010[How to Cite: V.R. Shelke, S.S. Bhagade, S.A. Mandavgane. (2010. Mesoporous Silica from Rice Husk Ash. Bulletin of Chemical Reaction Engineering and Catalysis, 5 (2: 63-67. doi:10.9767/bcrec.5.2.793.63-67][DOI: http://dx.doi.org/10.9767/bcrec.5.2.793.63-67

V.R. Shelke

2011-01-01

165

Mesoporous Silica from Rice Husk Ash  

Directory of Open Access Journals (Sweden)

Full Text Available Mesoporous silica is used as a raw material in several areas: in preparation of catalysts, in inks, as aconcrete hardening accelerator, as a component of detergents and soaps, as a refractory constituent etc.Sodium silicate is produced by reacting rice hull ash (RHA with aqueous NaOH and silica is precipitatedfrom the sodium silicate by acidification. In the present work, conversion of about 90% of silica containedin RHA into sodium silicate was achieved in an open system at temperatures of about 100 °C. The resultsshowed that silica obtained from RHA is mesoporous, has a large surface area and small particle size.Rice Husk is usually mixed with coal and this mixture is used for firing boilers. The RHA therefore, usuallycontains carbon particles. Activated carbon embedded on silica has been prepared using the carbon alreadypresent in RHA. This carbon shows good adsorption capacity. ©2010 BCREC UNDIP. All rights reserved(Received: 25th April 2010, Revised: 17th June 2010, Accepted: 24th June 2010[How to Cite: V.R. Shelke, S.S. Bhagade, S.A. Mandavgane. (2010. Mesoporous Silica from Rice Husk Ash. Bulletin of Chemical Reaction Engineering and Catalysis, 5 (2: 63-67. doi:10.9767/bcrec.5.2.793.63-67

S.A. Mandavgane

2010-12-01

166

Process for preparing hydrophilic resins  

International Nuclear Information System (INIS)

A process for preparing a radiation-curable hydrophilic resin is provided. The process comprises reacting a polyether-diamine having 3 to 20 ether linkages per one molecule (A) with a dicarboxylic acid (B) to give a polyamide having amino groups on its molecular terminals (C) followed by reacting C with an acrylic or methacrylic acid halide (D) or an epoxy-containing vinyl monomer to introduce vinyl groups into the molecular terminals of C. The resulting resin cures when irradiated with electron beams (dose rate 0.1 to 20 Mrad/sec) or light (wave length 3000 to 5000 A). Before the cure, the resin is water-soluble while after the cure it is still hydrophilic but insoluble in water due to the formed cross-linkages. Therefore it is useful for the surface treatment of textiles and the production of relief images. In one example, 416 parts of A is reacted with 306 parts of B to give C, which is then reacted with 90.4 parts of D to give the resin. A nylon taffeta is treated with an aqueous solution of the resin and then irradiated with electron beams (absorbed dose 8 Mrad). The treated cloth has durable water-affinity and antistatic properties. (Kaichi, S.)

167

21 CFR 177.2510 - Polyvinylidene fluoride resins.  

Science.gov (United States)

...fluoride resins. Polyvinylidene fluoride resins may be safely used...section, the polyvinylidene fluoride resins consist of basic resins...polymerization of vinylidene fluoride. (b) The finished food-contact...with the solvents distilled water, 50 percent (by...

2010-04-01

168

76 FR 4936 - Granular Polytetrafluoroethylene Resin From Italy  

Science.gov (United States)

...Granular Polytetrafluoroethylene Resin From Italy AGENCY: United States International Trade...resin (``granular PTFE resin'') from Italy...duty orders on granular PTFE resin from Italy and Japan (75 FR 67082-67083 and...

2011-01-27

169

Selectivity of ion exchangers in extracting cesium and rubidium from alkaline solutions  

Science.gov (United States)

We compare the ion exchange selectivity of phenol-type sorbents based on phenol formaldehyde resins, products of condensation of diatomic phenols with formaldehyde, and crosslinked polymer based on C-phenyl[4]resorcinarene resin, for cesium and rubidium ions. It is shown that phenol formaldehyde sorbents are the ones most selective. The interaction of alkali metal cations with the anion of calix[4]arene is investigated via quantum-chemical modeling. It is shown that the selectivity toward cesium and rubidium ions in ion exchangers of the phenolic type is not due to specific interactions of ions with phenolic groups.

Shelkovnikova, L. A.; Kargov, S. I.; Gavlina, O. T.; Ivanov, V. A.; Al'tshuler, G. N.

2013-01-01

170

Morphology control of ordered mesoporous carbons for high capacity lithium sulfur batteries  

Energy Technology Data Exchange (ETDEWEB)

The focus of this thesis concerns the morphology control of ordered mesoporous carbon (OMC) materials. Ordered mesoporous carbons with diverse morphologies, that are thin films, fibers - embedded in anodic alumina membranes and free-standing - or spherical nanoparticles, have been successfully prepared by soft-templating procedures. The mechanisms of structure formation and processing were investigated with in-situ SAXS measurements and their application in high capacity lithium-sulfur batteries was successfully tested in cooperation with Guang He and Linda Nazar from the University of Waterloo in Canada. The Li-S batteries receive increasing attention due to their high theoretical energy density which is 3 to 5 times higher than from lithium-ion batteries. For this type of battery the specific pore volume is crucial for the content of the active component (sulfur) in the cathode and therefore correlates with the capacity and gravimetric energy density of the battery. At first, mesoporous thin films with 2D-hexagonal structure were obtained through organic-organic self-assembly of a preformed oligomeric resol precursor and the triblock copolymer template Pluronic P123. The formation of a condensed-wall material through thermopolymerization of the precursor oligomers resulted in mesostructured phenolic resin films. Subsequent decomposition of the surfactant and partial carbonization were achieved through thermal treatment in inert atmosphere. The films were crack-free with tunable homogenous thicknesses, and showed either 2D-hexagonal or lamellar mesostructure. An additional, yet unknown 3D-mesostructure was also found. In the second part, cubic and circular hexagonal mesoporous carbon phases in the confined environment of tubular anodic alumina membrane (AAM) pores were obtained by self-assembly of the mentioned resol precursor and the triblock copolymer templates Pluronic F127 or P123, respectively. Casting and solvent-evaporation were also followed by thermopolymerization, thermal decomposition of the surfactant and carbonization through thermal treatment at temperatures up to 1000 C in an inert atmosphere. For both structures the AAM pores were completely filled and no shrinkage was observed, due to strong adhesion of the carbon wall material to the AAM pore walls. As a consequence of this restricted shrinkage effect, the mesophase system stayed almost constant even after thermal treatment at 1000 C, and pore sizes of up to 20 nm were obtained. In the third part, the aforementioned mesoporous films and embedded fibers in AAMs were further investigated concerning structure formation and carbonization in an in-situ SAXS study. The in-situ measurements revealed that for both systems the structure formation occurs during the thermopolymerization step. Therefore the process of structure formation differs significantly from the known evaporation-induced self-assembly (EISA) and may rather be viewed as thermally-induced self-assembly. As a result, the structural evolution strongly depends on the chosen temperature, which controls both the rate of the mesostructure formation and the spatial dimensions of the resulting mesophase. In the fourth part the syntheses recipes for AAMs were applied on a presynthesized silica template for synthesis of freestanding mesoporous carbon nanofibers. The syntheses start with casting of carbon nanofibers with a silica precursor solution leading to a porous silica template after calcination with tubular pores mimicking the initial carbon nanofibers. A synthesis concept using triconstituent coassembly of resol, tetraethylorthosilicate as additional silica precursor and Pluronic F127 was applied here. The silica from the additional precursor was found to be beneficial, due to reduced shrinkage and created additional porosity after etching it. Those OMC nanofibers therefore exhibited a very large surface area and a high pore volume of 2486 m{sup 2}/g and 2.06 cm{sup 3}/g, respectively. Due to their extremely high porosity values, those fibers were successfully applied as sulfur host and electrode

Schuster, Joerg David

2011-06-07

171

21 CFR 175.380 - Xylene-formaldehyde resins condensed with 4,4?-isopropylidenediphenol-epichlorohydrin epoxy resins.  

Science.gov (United States)

...isopropylidenediphenol-epichlorohydrin epoxy resins. 175.380 Section 175.380...isopropylidenediphenol-epichlorohydrin epoxy resins. The resins identified in...isopropylidenediphenol-epichlorohydrin epoxy resins, to which may have been...

2010-04-01

172

21 CFR 177.1680 - Polyurethane resins.  

Science.gov (United States)

...Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1680 Polyurethane resins. The polyurethane resins identified...of this section may be safely used as the food-contact surface of articles intended for use in...

2010-04-01

173

Crystals in crystals : Nanocrystals within mesoporous zeolite single crystals  

DEFF Research Database (Denmark)

A major factor governing the performance of catalytically active particles supported on a zeolite carrier is the degree of dispersion. It is shown that the introduction of noncrystallographic mesopores into zeolite single crystals (silicalite-1, ZSM-5) may increase the degree of particle dispersion. As representative examples, a metal (Pt), an alloy (PtSn), and a metal carbide (beta-Mo2C) were supported on conventional and mesoporous zeolite carriers, respectively, and the degree of particle dispersion was compared by TEM imaging. On conventional zeolites, the supported material aggregated on the outer surface of the zeolite particles, particularly after thermal treatment. When using mesoporous zeolites, the particles were evenly distributed throughout the mesopore system of the zeolitic support, even after calcination, leading to nanocrystals within mesoporous zeolite single crystals.

Christensen, Claus H.; Schmidt, I.

2005-01-01

174

Biodegradation-tunable mesoporous silica nanorods for controlled drug delivery.  

Science.gov (United States)

Mesoporous silica in the forms of micro- or nanoparticles showed great potentials in the field of controlled drug delivery. However, for precision control of drug release from mesoporous silica-based delivery systems, it is critical to control the rate of biodegradation. Thus, in this study, we demonstrate a simple and robust method to fabricate "biodegradation-tunable" mesoporous silica nanorods based on capillary wetting of anodic aluminum oxide (AAO) template with an aqueous alkoxide precursor solution. The porosity and nanostructure of silica nanorods were conveniently controlled by adjusting the water/alkoxide molar ratio of precursor solutions, heat-treatment temperature, and Na addition. The porosity and biodegradation kinetics of the fabricated mesoporous nanorods were analyzed using N2 adsorption/desorption isotherm, TGA, DTA, and XRD. Finally, the performance of the mesoporous silica nanorods as drug delivery carrier was demonstrated with initial burst and subsequent "zero-order" release of anti-cancer drug, doxorubicin. PMID:25746247

Park, Sung Bum; Joo, Young-Ho; Kim, Hyunryung; Ryu, WonHyoung; Park, Yong-Il

2015-05-01

175

Synthesis and catalytic applications of combined zeolitic/mesoporous materials  

Directory of Open Access Journals (Sweden)

Full Text Available In the last decade, research concerning nanoporous siliceous materials has been focused on mesoporous materials with intrinsic zeolitic features. These materials are thought to be superior, because they are able to combine (i the enhanced diffusion and accessibility for larger molecules and viscous fluids typical of mesoporous materials with (ii the remarkable stability, catalytic activity and selectivity of zeolites. This review gives an overview of the state of the art concerning combined zeolitic/mesoporous materials. Focus is put on the synthesis and the applications of the combined zeolitic/mesoporous materials. The different synthesis approaches and formation mechanisms leading to these materials are comprehensively discussed and compared. Moreover, Ti-containing nanoporous materials as redox catalysts are discussed to illustrate a potential implementation of combined zeolitic/mesoporous materials.

Jarian Vernimmen

2011-11-01

176

Mesoporous silicates: Materials science and biological applications  

Science.gov (United States)

This thesis dissertation presents the collective research into the advancement of mesoporous silicate particles as biointerface devices, the development of new materials and the application of these particles as solid supports for heterogeneous catalysis. Mesoporous silica has been utilized in the aforementioned applications due to several reasons; the first being the ability to achieve high surface areas (500 - 1000 m2 g-1) with controlled pore sizes and particle morphology. Another reason for their popularity is their robustness in applications of heterogeneous catalysis and the ability to functionalize the surface with a wide variety of organic functional groups. In the field of biointerface devices, mesoporous silica nanoparticles represent a class of materials that exhibit high biocompatibility. In addition, the ability to functionalize the surfaces (outer surface and pore interiors) allows the particles to be targeted to specific cell types as well as the ability to release many different therapeutic molecules under specific stimuli. A unique particle coating consisting of a chemically cleavable lipid bilayer that allows for the encapsulation of a fluorescent molecule and increases the biocompatibility of the particle has been developed. The lipid bilayer coated mesoporous silica nanoparticle (LB-MSN) was characterized using X-ray diffraction, transmission electron microscopy and nitrogen `sorption isotherms. The finished LB-MSN was then incubated with mammalian cells in order to prove their biocompatibility. Confocal micrographs demonstrate the endocytosis of the particles into the cells. In addition the micrographs also show that the LB-MSNs are separate from the endosomal compartments, however due to the lipophilic nature of the dye used to label the endosome there is some debate regarding this conclusion. The lipid bilayer coating was then applied to a large pore MSN (l-MSN) which had been previously shown to cause lysis of red blood cells (RBCs) at low concentrations of particles. The lipid bilayer allowed the particle to interface with particle without resulting in haemolysis. It was observed however, that spiculation (damage) of the RBCs still occurred despite the lack of cell lysis. During the course of the study, the composition of the outer leaflet of the lipid bilayer was altered to more closely match that of the outer leaflet of RBCs. This alteration proved to make the LB-l-MSN particle extremely compatible with RBCs in that spiculation of the cells was reduced by more than 50 % according to observations by scanning electron microscopy. A new synthetic route to mesoporous silica nanoparticles (MSNs) was developed using water in oil (W/O) emulsions was developed. This method relies on the presence of an amphiphilic stabilizer molecule to control the size and quality of the spherical morphology of the particles. Partitioning of the oil phase into cetyltrimethylammonium bromide surfactant molecules is implicated in expanding the size of the mesopores from the standard 3 nm pore to 7 nm. This material is extensively characterized using X-ray diffraction techniques and TEM microscopy. Chapter 3 also outlines the synthesis of a new periodic mesoporous organosilica (PMO) in which the bridging organic group is a benzobisoxazole molecule synthesized in the research group of Dr. Malika Jeffries-EL. While no immediate application of this new particle was proven, we propose this structure as the basis for a new class of light harvesting or light emitting diode material based on the performance of the polymers containing these benzobisoxazole moieties and functionalized dyes. The final project was the initial development of an N-heterocyclic carbene ligand based on an imidazole framework. This project represents significant synthetic challenges in that the pattern of substitution on the imidazole framework has not been reported in the literature to the best of our knowledge. Despite the synthetic challenges, significant progress has been made towards the goal of generating an MSN with a functional group capable of c

Roggers, Robert Anthony

177

Modified BET Equation for Determination of Micropore Pore Volume and Mesopore Surface Area in Microporous-Mesoporous Solids.  

Czech Academy of Sciences Publication Activity Database

Cambridge : RSC Publishing, 2009, s. 218-224 ISBN 978-1-84755-904-3 R&D Projects: GA AV ?R IAA4072404; GA AV ?R KAN400720701 Institutional research plan: CEZ:AV0Z40720504 Keywords : microporous-mesoporous solids * mesopore surface area Subject RIV: CF - Physical ; Theoretical Chemistry

Šolcová, Olga; Mat?jová, Lenka; Hudec, P.; Schneider, Petr

178

Method for removing contaminants from plastic resin  

Science.gov (United States)

A method for removing contaminants from synthetic resin material containers using a first organic solvent system and a second carbon dioxide system. The organic solvent is utilized for removing the contaminants from the synthetic resin material and the carbon dioxide is used to separate any residual organic solvent from the synthetic resin material.

Bohnert, George W. (Harrisonville, MO); Hand, Thomas E. (Lee's Summit, MO); DeLaurentiis, Gary M. (Jamestown, CA)

2008-12-30

179

Method of removing contaminants from plastic resins  

Science.gov (United States)

A method for removing contaminants from synthetic resin material containers using a first organic solvent system and a second carbon dioxide system. The organic solvent is utilized for removing the contaminants from the synthetic resin material and the carbon dioxide is used to separate any residual organic solvent from the synthetic resin material.

Bohnert, George W. (Harrisonville, MO); Hand, Thomas E. (Lee's Summit, MO); DeLaurentiis, Gary M. (Jamestown, CA)

2008-11-18

180

Contribution of mesopores in MgO-templated mesoporous carbons to capacitance in non-aqueous electrolytes  

Science.gov (United States)

MgO-templated mesoporous carbons were fabricated by annealing trimagnesium dicitrate nonahydrate at various temperatures from 700 to 1000 °C with subsequent acid leaching of MgO. The obtained carbons contained a large amount of mesopores. Performances of electric double-layer capacitors using these carbons were examined for propylene carbonate electrolyte containing 1 M tetraethylammonium tetrafluoroborate. The mesoporous carbons synthesized at higher temperatures showed better rate capabilities. AC impedance measurements indicated that high-temperature annealing of the carbon precursors and the presence of mesopores were important for high rate performance. In addition, the contribution of mesopores to capacitance was more significant at higher current densities of 30 A g-1.

Kado, Yuya; Soneda, Yasushi; Yoshizawa, Noriko

2015-02-01

181

Process for curing bismaleimide resins  

Science.gov (United States)

This invention relates to vinyl pyridine group containing compounds and oligomers, their advantageous copolymerization with bismaleimide resins, and the formation of reinforced composites based on these copolymers. When vinyl pyridines including vinyl stilbazole materials and vinyl styrylpyridine oligomer materials are admixed with bismaleimides and cured to form copolymers the cure temperatures of the copolymers are substantially below the cure temperatures of the bismaleimides alone.

Parker, John A. (inventor); OTHY S.imides alone. (inventor)

1986-01-01

182

Synthesis of improved phenolic resins  

Science.gov (United States)

Twenty seven addition cured phenolic resin compositions were prepared and tested for their ability to give char residues comparable to state-of-the-art phenolic resins. Cyanate, epoxy, allyl, acrylate, methacrylate and ethynyl derivatized phenolic oligomers were investigated. The novolac-cyanate and propargyl-novolac resins provided anaerobic char yields at 800 C of 58 percent. A 59 percent char yield was obtained from modified epoxy novolacs. A phosphonitrilic derivative was found to be effective as an additive for increasing char yields. The novolac-cyanate, epoxy-novolac and methacrylate-epoxy-novolac systems were investigated as composite matrices with Thornel 300 graphite fiber. All three resins showed good potential as composite matrices. The free radical cured methacrylate-epoxy-novolac graphite composite provided short beam shear strengths at room temperature of 93.3 MPa (13.5 ksi). The novolac-cyanate graphite composite produced a short beam shear strength of 74 MPa (10.7 ksi) and flexural strength of 1302 MPa (189 ksi) at 177 C. Air heat aging of the novolac-cyanate and epoxy novolac based composites for 12 weeks at 204 C showed good property retention.

Delano, C. B.; Mcleod, A. H.

1979-01-01

183

The development of chiral nematic mesoporous materials.  

Science.gov (United States)

Cellulose nanocrystals (CNCs) are obtained from the sulfuric acid-catalyzed hydrolysis of bulk cellulose. The nanocrystals have diameters of ~5-15 nm and lengths of ~100-300 nm (depending on the cellulose source and hydrolysis conditions). This lightweight material has mostly been investigated to reinforce composites and polymers because it has remarkable strength that rivals carbon nanotubes. But CNCs have an additional, less explored property: they organize into a chiral nematic (historically referred to as cholesteric) liquid crystal in water. When dried into a thin solid film, the CNCs retain the helicoidal chiral nematic order and assemble into a layered structure where the CNCs have aligned orientation within each layer, and their orientation rotates through the stack with a characteristic pitch (repeating distance). The cholesteric ordering can act as a 1-D photonic structure, selectively reflecting circularly polarized light that has a wavelength nearly matching the pitch. During CNC self-assembly, it is possible to add sol-gel precursors, such as Si(OMe)4, that undergo hydrolysis and condensation as the solvent evaporates, leading to a chiral nematic silica/CNC composite material. Calcination of the material in air destroys the cellulose template, leaving a high surface area mesoporous silica film that has pore diameters of ~3-10 nm. Importantly, the silica is brilliantly iridescent because the pores in its interior replicate the chiral nematic structure. These films may be useful as optical filters, reflectors, and membranes. In this Account, we describe our recent research into mesoporous films with chiral nematic order. Taking advantage of the chiral nematic order and nanoscale of the CNC templates, new functional materials can be prepared. For example, heating the silica/CNC composites under an inert atmosphere followed by removal of the silica leaves highly ordered, mesoporous carbon films that can be used as supercapacitor electrodes. The composition of the mesoporous films can be varied by using assorted organosilica precursors. After removal of the cellulose by acid-catalyzed hydrolysis, highly porous, iridescent organosilica films are obtained. These materials are flexible and offer the ability to tune the chemical and mechanical properties through variation of the organic spacer. Chiral nematic mesoporous silica and organosilica materials, obtainable as centimeter-scale freestanding films, are interesting hosts for nanomaterials. When noble metal nanoparticles are incorporated into the pores, they show strong circular dichroism signals associated with their surface plasmon resonances that arise from dipolar coupling of the particles within the chiral nematic host. Fluorescent conjugated polymers show induced circular dichroism spectra when encapsulated in the chiral nematic host. The porosity, film structure, and optical properties of these materials could enable their use in sensors. We describe the development of chiral nematic mesoporous silica and organosilica, demonstrate different avenues of host-guest chemistry, and identify future directions that exploit the unique combination of properties present in these materials. The examples covered in this Account demonstrate that there is a rich diversity of composite materials accessible using CNC templating. PMID:24694253

Kelly, Joel A; Giese, Michael; Shopsowitz, Kevin E; Hamad, Wadood Y; MacLachlan, Mark J

2014-04-15

184

Fractionation and utilization of gossypol resin  

Energy Technology Data Exchange (ETDEWEB)

Gossypol resin is formed as a secondary waste product during distillation of fatty acides isolated from cottonseed oil soap stocks; it is insoluble in water but soluble in products of petroleum distillation. For fractionation, gossypol resin was saponified with caustic soda or caustic potash. Using this method, the resin was separated into unsaponifiable (21-24%) and saponifiable (76-79%) parts. Details of the individual fractions of gossypol resin are presented. The unsaponifiable fraction contains hydrocarbons, alcohols, beta-sito-sterol, beta-amyrin, and vitamin E. The fatty acid fraction of the resin is a mixture of fatty acids and lactones.

Tursunov, A.K.; Dzhailov, A.T.; Fatkhullaev, E.; Sadykov, A.A.

1985-10-01

185

Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery  

International Nuclear Information System (INIS)

The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N2 adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation ft=ktn was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties. - Graphical abstract: Loading (A) and release profiles (B) of aspirin in N-BMMs and N-MCM-41 indicated that BMMs have more drug loading capacity and faster release rate than that MCM-41. Highlights: ? Bimodal mesoporous silicas (BMMs) and MCM-41 modified with amino group via post-treatment procedure. ? Loading and release profiles of aspirin in modified BMMs and MCM-41. ? Modified BMMs have more drug -41. ? Modified BMMs have more drug loading capacity and faster release rate than that modified MCM-41.

186

Ordered mesoporous silica-based inorganic nanocomposites  

International Nuclear Information System (INIS)

This article reviews the synthesis and characterization of nanoparticles and nanowires grown in ordered mesoporous silicas (OMS). Summarizing work performed over the last 4 years, this article highlights the material properties of the final nanocomposite in the context of the synthesis methodology employed. While certain metal-OMS systems (e.g. gold in MCM-41) have been extensively studied this article highlights that there is a rich set of chemistries that have yet to be explored. The article concludes with some thoughts on future developments and challenges in this area. - Graphical abstract: HAADF TEM image of gold nanoparticles in amine-functionalized MCM-41 (from Ref. [22])

187

Fluorescence properties of dye doped mesoporous silica  

Energy Technology Data Exchange (ETDEWEB)

In this paper we present a review of the main results we obtained studying the emission properties of organic-inorganic hybrids obtained combining mesoporous silica and Xantene dyes, in particular the standard reference Rhodamine 6G. The purpose of the review is to show the possibility to efficiently 'dope' the transparent inorganic porous matrix to obtain promising systems for photonic and biomedical applications. The strategies to solve the concentration effect and the leaching phenomenon are discussed within the framework of the single exciton theory.

Carbonaro, Carlo M., E-mail: cm.carbonaro@dsf.unica.it; Corpino, Riccardo, E-mail: cm.carbonaro@dsf.unica.it; Ricci, Pier Carlo, E-mail: cm.carbonaro@dsf.unica.it; Chiriu, Daniele, E-mail: cm.carbonaro@dsf.unica.it [Department of Physics, University of Cagliari, Campus of Monserrato, s.p. no 8, km 0.700, 09042 Monserrato (Italy); Cannas, Carla [Department of Chemical and Geological Sciences, University of Cagliari, Campus of Monserrato, s.p. no 8, km 0.700, 09042 Monserrato (Italy)

2014-10-21

188

The formation of helical mesoporous silica nanotubes  

International Nuclear Information System (INIS)

Three chiral cationic gelators were synthesized. They can form translucent hydrogels in pure water. These hydrogels become highly viscous liquids under strong stirring. Mesoporous silica nanotubes with coiled pore channels in the walls were prepared using the self-assemblies of these gelators as templates. The mechanism of the formation of this hierarchical nanostructure was studied using transmission electron microscopy at different reaction times. The results indicated that there are some interactions between the silica source and the gelator. The morphologies of the self-assemblies of gelators changed gradually during the sol-gel transcription process. It seems that the silica source directed the organic self-assemblies into helical nanostructures

189

Performance of templated mesoporous carbons in supercapacitors  

OpenAIRE

By analogy with other types of carbons, templated mesoporous carbons (TMCs) can be used as supercapacitors. Their contribution arises essentially from the double layer capacity formed on their surface, which corresponds to 0.14 F m?2 in aqueous electrolytes such as H2SO4 and KOH and 0.06 F m?2 for the aprotic medium (C2H5)4NBF4 in CH3CN. In the case of a series of 27 TMCs, it appears that the effective surface area determined by independent techniques can be as high as 1500–1600 m2 g?...

Sevilla, M.; A?lvarez, S.; Centeno, Teresa A.; Fuertes, A. B.; Stoeckli, Fritz

2008-01-01

190

Crystalline mesoporous zirconia catalysts having stable tetragonal pore wall structure  

Science.gov (United States)

Methods for the preparation of new sulfated mesoporous zirconia materials/catalysts with crystalline pore walls of predominantly tetragonal crystal structure, characterized by nitrogen physisorption measurement, X-ray diffraction, transmission electron microscopy and catalytic tests using n-butane isomerization to iso-butane and alkylation of 1-naphthol with 4-tert-butylstyrene as probe reactions. Sulfate deposition is preferred for the transformation of a mesoporous precursor with amorphous pore walls into a material with crystalline pore walls maintaining the mesoporous characteristics.

Sachtler, Wolfgang M. H. (Evanston, IL); Huang, Yin-Yan (Evanston, IL)

1998-01-01

191

Fabrication of the hydrogen-evolving photocatalyst with mesoporous structure  

Energy Technology Data Exchange (ETDEWEB)

The photocatalyst TiO{sub 2} with a wormhole-like mesoporous structure and narrow pore distribution were successfully synthesized using triethanolamine as template. The complex oxides InVO{sub 4} with a relatively high surface area, a visible light active hydrogen-evolving photocatalyst, were obtained by means of the templating hydrothermal method with a variety of surfactants. InVO{sub 4} with wormhole-like structure were fabricated by templating of cetyltrimethylammonium bromide. By comparing with the non-mesoporous samples, the mesoporous photocatalysts exhibited higher photocatalytic hydrogen evolution activity for water splitting in the absence and in the presence of oxalic acid. (author)

Sang, Lixia; Xu, Lixian; Wang, Feng; Ma, Chongfang [Key Laboratory of Enhanced Heat Transfer and Energy Conservation, Ministry of Education and Key Laboratory of Heat Transfer and Energy Conversion, Beijing Municipality, Beijing University of Technology, Beijing 100124 (China); Dai, Hongxing; Sun, Jihong [Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124 (China)

2010-07-15

192

40 CFR 414.40 - Applicability; description of the thermoplastic resins subcategory.  

Science.gov (United States)

...Olefins Polyacrylic Acid *Polyamides *Polyarylamides Polybutadiene... Polystyrene (Crystal) Modified *Polystyrene—Copolymers...Acrylic Latexes Polystyrene Impact Resins Polystyrene Latex...Derivative Resins *Rosin Modified Resins *Rosin Resins...

2010-07-01

193

Pharmaceutical Applications of Ion-Exchange Resins  

Science.gov (United States)

The historical uses of ion-exchange resins and a summary of the basic chemical principles involved in the ion-exchange process are discussed. Specific applications of ion-exchange resins are provided. The utility of these agents to stabilize drugs are evaluated. Commonly occurring chemical and physical incompatibilities are reviewed. Ion-exchange resins have found applicability as inactive pharmaceutical constituents, particularly as disintegrants (inactive tablet ingredient whose function is to rapidly disrupt the tablet matrix on contact with gastric fluid). One of the more elegant approaches to improving palatability of ionizable drugs is the use of ion-exchange resins as taste-masking agents. The selection, optimization of drug:resin ratio and particle size, together with a review of scaleup of typical manufacturing processes for taste-masked products are provided. Ion-exchange resins have been extensively utilized in oral sustained-release products. The selection, optimization of drug:resin ratio and particle size, together with a summary of commonly occurring commercial sustained-release products are discussed. Ion-exchange resins have also been used in topical products for local application to the skin, including those where drug flux is controlled by a differential electrical current (ionotophoretic delivery). General applicability of ion-exchange resins, including ophthalmic delivery, nasal delivery, use as drugs in their own right (e.g., colestyramine, formerly referred to as cholestyramine), as well as measuring gastrointestinal transit times, are discussed. Finally, pharmaceutical monographs for ion-exchange resins are reviewed.

Elder, David P.

2005-04-01

194

Epoxy-diane resin dosimeter  

International Nuclear Information System (INIS)

The capacity of polymer materials to change their properties under the influence of ionizing radiation makes them candidate materials for dosimetry. Most polymers have been found, however, to have an upper absorbed dosage limit in the range of 0.1-1 MGy. The possibility of raising this limit led the authors of this paper to assess the value of an epoxy-diane resin as a candidate dosimetric material. Irradiation was performed with cobalt 60 and also with a 1.2 MeV electron beam. Chemical and physical radiation effects were measured on the basis of changes in refractivity and optical dispersion behavior of the resin. Temperature-dependent results for absorbed doses of up to 5 MGy are tabulated. Calibration procedures are proposed

195

Synthesis and characterization of new mesoporous material with conducting polypyrrole confined in mesoporous silica  

Energy Technology Data Exchange (ETDEWEB)

A new nanocomposite, semiconducting polypyrrole (PPy) confined in mesoporous silica (MCM-41) has been synthesized. PPy was formed in the pores of MCM-41 by adsorption of pyrrole gas and subsequent oxidative polymerization with FeCl{sub 3}.6H{sub 2}O. Different techniques were used to characterize the nanocomposite formation. X-ray diffraction (XRD) and N{sub 2} adsorption/desorption analysis show that the nanocomposite possesses mesoporous structure, and the residual pore volume of nanocomposite is significantly lower than that of pure empty MCM-41. FTIR spectra, high resolution transmission electron micrographs and electrical conductivity measurements confirmed the presence of polypyrrole inside pore channels of the host, and thermogravimetric analysis proved confinement effect in the channel system.

Cheng Qilin [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Box 258, 130 Meilong Road, 200237 Shanghai (China); Polymer Centre, Faculty of Technology, Tomas Bata University in Zlin, 762 72 Zlin (Czech Republic); Pavlinek, Vladimir [Polymer Centre, Faculty of Technology, Tomas Bata University in Zlin, 762 72 Zlin (Czech Republic); Li Chunzhong [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Box 258, 130 Meilong Road, 200237 Shanghai (China)]. E-mail: czli@ecust.edu.cn; Lengalova, Anezka [University Institute, Tomas Bata University in Zlin, 762 72 Zlin (Czech Republic); He Ying [Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Box 258, 130 Meilong Road, 200237 Shanghai (China); Saha, Petr [Polymer Centre, Faculty of Technology, Tomas Bata University in Zlin, 762 72 Zlin (Czech Republic)

2006-08-01

196

Synthesis and characterization of new mesoporous material with conducting polypyrrole confined in mesoporous silica  

International Nuclear Information System (INIS)

A new nanocomposite, semiconducting polypyrrole (PPy) confined in mesoporous silica (MCM-41) has been synthesized. PPy was formed in the pores of MCM-41 by adsorption of pyrrole gas and subsequent oxidative polymerization with FeCl3.6H2O. Different techniques were used to characterize the nanocomposite formation. X-ray diffraction (XRD) and N2 adsorption/desorption analysis show that the nanocomposite possesses mesoporous structure, and the residual pore volume of nanocomposite is significantly lower than that of pure empty MCM-41. FTIR spectra, high resolution transmission electron micrographs and electrical conductivity measurements confirmed the presence of polypyrrole inside pore channels of the host, and thermogravimetric analysis proved confinement effect in the channel system

197

Influence of uron resins on the performance of UF resins as adhesives for plywood  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in english Uron resin, a kind of urea-formaldehyde (UF) resin containing much more uron structure, were prepared. Several modified UF resins were obtained from mixing uron resins with normal UF resins as well as synthesizing UF resin with uron resin as raw material. This work demonstrated that the introducing [...] of the uron structure reduced free formaldehyde content of UF resin and formaldehyde emission levels in bonded plywood panels significantly, the former were reduced by 76% and 84% in the latter. The synthesis time of uron resin can be shortened to 8 hours. The test result of free formaldehyde content, formaldehyde emission levels and bond strength indicated that specimen of 20 parts uron resin synthesized in 8 hours mixed with 100 parts UF resins (F/U molar ratio of 1.3) had a potential advantage to industrial application. The beneficial effect of uron resin on the performance of UF resin can be attributed to the opening of uron cycle structure and the following reaction with free formaldehyde and its oligomeric glycol forms.

Wei, Gao; Jianzhang, Li.

198

Mesoporous zeolite single crystals for catalytic hydrocarbon conversion  

DEFF Research Database (Denmark)

Recently, mesoporous zeolite single crystals were discovered. They constitute a novel family of materials that features a combined micropore and mesopore architecture within each individual crystal. Here, we briefly summarize recent catalytic results from cracking and isomerization of alkalies, alkylation of aromatics and present new results on isomerization of aromatics. Specifically, the shape-selective isomerization of meta-xylenc into para-xylene and ortho-xylene is studied. In all these reactions, rnesoporous zeolite single crystals prove to be unique catalysts since they provide easy transport to and from active sites and at the same time maintain the shape-selectivity required. Thus, all these results support the idea that the beneficial effect of the mesopores system in the mesoporous zeolite single crystals call be solely attributed to enhanced mass transport.

Schmidt, I.; Christensen, C.H.

2005-01-01

199

Functionalization of colloidal mesoporous silica by metalorganic reagents.  

Science.gov (United States)

The concept of mesoporous silica functionalization via metalorganic reagents, demonstrated with phenyllithium, is transferred from micrometer-sized MCM-41 materials to colloidal suspensions containing mesoporous silica nanoparticles. Due to the different nature of the nanosized system, particle agglomeration and coalescence were found to be a major issue. Various approaches for the preparation of anhydrous colloidal systems via removal of water from the mesopores were compared. It was found that the most promising approaches for water removal at temperatures below 100 degrees C are the controlled hydrolysis of additives (triethyl orthoformate) and absorption from the vapor phase by molecular sieves. Both methods avoid the hydrolysis of the phenyllithium reagent and yield nonagglomerated suspensions of phenyl-functionalized colloidal mesoporous silica nanoparticles, thus demonstrating the feasibility of the metalorganic conversion route in nanosized porous silica systems. PMID:19360945

Kecht, Johann; Bein, Thomas

2008-12-16

200

Thermally stable crystalline mesoporous metal oxides with substantially uniform pores  

Energy Technology Data Exchange (ETDEWEB)

Highly crystalline metal oxide-carbon composites, as precursors to thermally stable mesoporous metal oxides, are coated with a layer of amorphous carbon. Using a `one-pot` method, highly crystalline metal oxide-carbon composites are converted to thermally stable mesoporous metal oxides, having highly crystalline mesopore walls, without causing the concomitant collapse of the mesostructure. The `one-pot` method uses block copolymers with an sp or sp 2 hybridized carbon containing hydrophobic block as structure directing agents which converts to a sturdy, amorphous carbon material under appropriate heating conditions, providing an in-situ rigid support which maintains the pores of the oxides intact while crystallizing at temperatures as high as 1000 deg C. A highly crystalline metal oxide-carbon composite can be heated to produce a thermally stable mesoporous metal oxide consisting of a single polymorph.

Wiesner, Ulrich; Orilall, Mahendra Christopher; Lee, Jinwoo; DiSalvo, Jr., Francis J

2015-01-27

201

Mesoporous metal organic framework-boehmite and silica composites.  

Science.gov (United States)

Mesoporous composites of metal organic frameworks (MOFs) with boehmite and silica were prepared by one-pot microwave hydrothermal synthesis in the presence of Pluronic-type triblock-copolymer. PMID:20717603

Górka, Joanna; Fulvio, Pasquale F; Pikus, Stanis?aw; Jaroniec, Mietek

2010-09-28

202

Core/shell magnetic mesoporous silica nanoparticles with radially oriented wide mesopores  

OpenAIRE

Core/shell nanoparticles, containing magnetic iron-oxide (maghemite) core and mesoporous shell with radial porous structure, were prepared by dispersing magnetite nanoparticles and adding tetraethylorthosilicate to a basic aqueous solution containing structure-templating cetyltrimethylammonium bromide and a pore-swelling mesithylene. The material is characterized by SEM and TEM imaging, nitrogen sorption and powder X-ray di?raction. Distinctive features of the prepared material are its high...

Z?, Nikola Knez?evic?

2014-01-01

203

Boron sorption characteristics in resins  

International Nuclear Information System (INIS)

The purpose of boron addition in a nuclear power plant is to control the reactivity. In PHWRs, it is injected into the moderator system in the form of boric anhydride solution, while in PHWRs, it is added to the primary heat transport system in the form of boric acid solution. The required boron levels in PHWRs are controlled by valving in strong base anion exchangers having exchangeable species in OD- form while in PHWRs, the same can be achieved by restoring to the use of Boron Thermal Regeneration System (BTRS). This system operates on the principle of existence of different amounts of various polyborate ions at different temperatures, solution pH's and the boric acid concentrations and on the reversible sorption of these polyions on strong base anion exchange resins. This report describes the salient features of boron sorption characteristics on four types of anion exchange resins, based on experimental data generated in the chemical laboratories of Reactor Engineering Division of the Bhabha Atomic Research Centre, Bombay. The report further makes an attempt to calculate the pH of the resin and solution phases and the percentages of different polyborates and undissociated boric acid, under the experimental conditions investigated. (author). 30 refs., 4 figs., 20 tables

204

Radiation effect of epoxy resin by electron beams  

International Nuclear Information System (INIS)

The study was aimed at understanding behaviors of epoxy resins under electron beam irradiation, Epoxy resins of different molecular structures, which include glycidyl ether resin, glycidyl ester resin, glycidyl amine resin, and alicyclic epoxy resin, were irradiated with 5 MeV electron beams. The irradiated samples were investigated with their viscosity changes, weight losses and gaseous molecules generated by the irradiation. The results show that the glycidyl ester resin and the epoxy containing ester group underwent the most serious decomposition by the irradiation, while the glycidyl amine resin was decomposed less seriously and the glycidyl ether resin was the least decomposed. (authors)

205

Exploring Mass Transfer in Mesoporous Zeolites by NMR Diffusometry  

OpenAIRE

With the advent of mesoporous zeolites, the exploration of their transport properties has become a task of primary importance for the auspicious application of such materials in separation technology and heterogeneous catalysis. After reviewing the potential of the pulsed field gradient method of NMR (PFG NMR) for this purpose in general, in a case study using a specially prepared mesoporous zeolite NaCaA as a host system and propane as a guest molecule, examples of the attainable information...

Ryong Ryoo; Kanghee Cho; Jörg Kärger; Rustem Valiullin; Dirk Mehlhorn

2012-01-01

206

Recent Advances in Catalysis Over Mesoporous Molecular Sieves.  

Czech Academy of Sciences Publication Activity Database

Ro?. 53, 3-4 (2010), s. 141-153. ISSN 1022-5528 R&D Projects: GA AV ?R KAN100400701; GA AV ?R IAA400400805; GA ?R GA104/09/0561 Institutional research plan: CEZ:AV0Z40400503 Keywords : mesoporous molecular sieves * MCM-41 * SBA-15 * mesoporous alumina Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.359, year: 2010

Martín-Aranda, R. M.; ?ejka, Ji?í

2010-01-01

207

Near-infrared emission from mesoporous crystalline germanium  

Science.gov (United States)

Mesoporous crystalline germanium was fabricated by bipolar electrochemical etching of Ge wafer in HF-based electrolyte. It yields uniform mesoporous germanium layers composed of high density of crystallites with an average size 5-7 nm. Subsequent extended chemical etching allows tuning of crystallites size while preserving the same chemical composition. This highly controllable nanostructure exhibits photoluminescence emission above the bulk Ge bandgap, in the near-infrared range (1095-1360nm) with strong evidence of quantum confinement within the crystallites.

Boucherif, Abderraouf; Korinek, Andreas; Aimez, Vincent; Arès, Richard

2014-10-01

208

Near-infrared emission from mesoporous crystalline germanium  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous crystalline germanium was fabricated by bipolar electrochemical etching of Ge wafer in HF-based electrolyte. It yields uniform mesoporous germanium layers composed of high density of crystallites with an average size 5-7 nm. Subsequent extended chemical etching allows tuning of crystallites size while preserving the same chemical composition. This highly controllable nanostructure exhibits photoluminescence emission above the bulk Ge bandgap, in the near-infrared range (1095-1360nm) with strong evidence of quantum confinement within the crystallites.

Boucherif, Abderraouf; Aimez, Vincent; Arès, Richard, E-mail: richard.ares@usherbrooke.ca [Institut Interdisciplinaire d’Innovation Technologique (3IT), Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, J1K OA5, Québec (Canada); Laboratoire Nanotechnologies Nanosystèmes (LN2)-CNRS UMI-3463, Université de Sherbrooke, 3000 Boulevard Université, Sherbrooke, J1K OA5, Québec (Canada); Korinek, Andreas [Canadian Centre for Electron Microscopy, Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario, L8S 4M1 (Canada)

2014-10-15

209

Highly Aminated Mesoporous Silica Nanoparticles with Cubic Pore Structure  

OpenAIRE

Mesoporous silica with cubic symmetry has attracted interest from researchers for some times. Here we present the room temperature synthesis of mesoporous silica nanoparticles possessing cubic Pm3?n symmetry with very high molar ratios (>50%) of 3-aminopropyl triethoxysilane. The synthesis is robust allowing, e.g. for co-condensation of organic dyes without loss of structure. By means of pore expander molecules, the pore size can be enlarged from 2.7 to 5 nm, while particle size decreases. A...

Suteewong, Teeraporn; Sai, Hiroaki; Cohen, Roy; Wang, Suntao; Bradbury, Michelle; Baird, Barbara; Gruner, Sol M.; Wiesner, Ulrich

2010-01-01

210

Hollow mesoporous silica nanoparticles for intracellular delivery of fluorescent dye  

OpenAIRE

Abstract In this study, hollow mesoporous silica nanoparticles (HMSNs) were synthesized using the sol-gel/emulsion approach and its potential application in drug delivery was assessed. The HMSNs were characterized, by transmission electron microscopy (TEM), Scanning Electron Microscopy (SEM), nitrogen adsorption/desorption and Brunauer-Emmett-Teller (BET), to have a mesoporous layer on its surface, with an average pore diameter of about 2 nm and a surface area of 880 m2/g. Fluorescein isothio...

Jiang Tao; Wu Jinyan; Liu Zaixin; Cai Xuepeng; Yin Hong; Sun Dehui; Qian Haisheng; Sun Shiqi; Guo Huichen; Liu Xiangtao

2011-01-01

211

Near-infrared emission from mesoporous crystalline germanium  

International Nuclear Information System (INIS)

Mesoporous crystalline germanium was fabricated by bipolar electrochemical etching of Ge wafer in HF-based electrolyte. It yields uniform mesoporous germanium layers composed of high density of crystallites with an average size 5-7 nm. Subsequent extended chemical etching allows tuning of crystallites size while preserving the same chemical composition. This highly controllable nanostructure exhibits photoluminescence emission above the bulk Ge bandgap, in the near-infrared range (1095-1360nm) with strong evidence of quantum confinement within the crystallites

212

Adsorption of acetone on nonporous and mesoporous silica  

OpenAIRE

The ambient temperature solid/gas interaction of acetone with a nonporous silica (Aerosil 200) and two mesoporous silicas (a spherical MCM-41 preparation, with highly uniform and very small meso-pores, and a reference conventional MCM-41 preparation), vacuum activated at different temperatures, has been investigated by the combined use of gas-volumetry/adsorption-microcalorimetry and in situ FTIR spectroscopy. In the early stages of acetone uptake, when no physical adsorption occu...

Morterra, Claudio; Crocella, Valentina; Magnacca, Giuliana; Cerrato, Giuseppina

2009-01-01

213

Rapid synthesis of ordered hexagonal mesoporous silica and their incorporation with Ag nanoparticles by solution plasma  

Energy Technology Data Exchange (ETDEWEB)

Graphical abstract: Overall reactions of mesoporous silica and AgNPs-incorporated mesoporous silica syntheses by solution plasma process (SPP). Highlights: ? SPP for rapid synthesis of mesoporous silica. ? SPP for rapid synthesis of mesoporous silica and AgNPs incorporation. ? Higher surface area and larger pore diameter of mesoporous silica synthesized by SPP. -- Abstract: Rapid synthesis of silica with ordered hexagonal mesopore arrangement was obtained using solution plasma process (SPP) by discharging the mixture of P123 triblock copolymer/TEOS in acid solution. SPP, moreover, was utilized for Ag nanoparticles (AgNPs) incorporation in silica framework as one-batch process using silver nitrate (AgNO{sub 3}) solution as precursor. The turbid silicate gel was clearly observed after discharge for 1 min and the white precipitate formed at 3 min. The mesopore with hexagonal arrangement and AgNPs were observed in mesoporous silica. Two regions of X-ray diffraction patterns (2? < 2° and 2? = 35–90°) corresponded to the mesoporous silica and Ag nanocrystal characteristics. Comparing with mesoporous silica prepared by a conventional sol–gel route, surface area and pore diameter of mesoporous silica prepared by solution plasma were observed to be larger. In addition, the increase in Ag loading resulted in the decrease in surface area with insignificant variation in the pore diameter of mesoporous silica. SPP could be successfully utilized not only to enhance gelation time but also to increase surface area and pore diameter of mesoporous silica.

Pootawang, Panuphong, E-mail: p.pootawang@gmail.com [Center for Surface Technology and Applications, Department of Materials Engineering, Korea Aerospace University, 100 Hanggongdae-gil, Hwajeon-dong, Deogyang-gu, Goyang-city, Gyeonggi-do 412-791 (Korea, Republic of); Saito, Nagahiro; Takai, Osamu [EcoTopia Science and Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Lee, Sang Yul [Center for Surface Technology and Applications, Department of Materials Engineering, Korea Aerospace University, 100 Hanggongdae-gil, Hwajeon-dong, Deogyang-gu, Goyang-city, Gyeonggi-do 412-791 (Korea, Republic of)

2012-10-15

214

Rapid synthesis of ordered hexagonal mesoporous silica and their incorporation with Ag nanoparticles by solution plasma  

International Nuclear Information System (INIS)

Graphical abstract: Overall reactions of mesoporous silica and AgNPs-incorporated mesoporous silica syntheses by solution plasma process (SPP). Highlights: ? SPP for rapid synthesis of mesoporous silica. ? SPP for rapid synthesis of mesoporous silica and AgNPs incorporation. ? Higher surface area and larger pore diameter of mesoporous silica synthesized by SPP. -- Abstract: Rapid synthesis of silica with ordered hexagonal mesopore arrangement was obtained using solution plasma process (SPP) by discharging the mixture of P123 triblock copolymer/TEOS in acid solution. SPP, moreover, was utilized for Ag nanoparticles (AgNPs) incorporation in silica framework as one-batch process using silver nitrate (AgNO3) solution as precursor. The turbid silicate gel was clearly observed after discharge for 1 min and the white precipitate formed at 3 min. The mesopore with hexagonal arrangement and AgNPs were observed in mesoporous silica. Two regions of X-ray diffraction patterns (2? < 2° and 2? = 35–90°) corresponded to the mesoporous silica and Ag nanocrystal characteristics. Comparing with mesoporous silica prepared by a conventional sol–gel route, surface area and pore diameter of mesoporous silica prepared by solution plasma were observed to be larger. In addition, the increase in Ag loading resulted in the decrease in surface area with insignificant variation in the pore diameter of mesoporous silica. SPP could be successfully utilized not only to enhance gelation time but also to increase surface area and pore diameter of mesoporous silica.

215

Reinforcement of Denture Base Resins  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction: PMMA has been the most popular denture base material because of its advantages including good aesthetics, accurate fit, stability in the oral environment, easy laboratory and clinical manipulation and inexpensive equipments since the 1930’s. However, its fracture resistance is not satisfactory. Aim: The aim of this study is to improve the fracture resistance of denture bases made of PMMA by assessing the effect of resin type, packing and processing variables on biaxial flexural strength (BFS. Materials & methods: 930 discs, 12 mm diameter and 2 mm thick were prepared with the following variables: a. Veined (V and Plain (P PMMA. b. 5 different powder/liquid ratios by volume (1.5:1, 2:1, 2.5:1, 3:1, 3.5:1. c. Conventional (C and Injection packing methods (I. d. Dry heat (D Water bath (W; and e. different curing times. The discs were trimmed and stored in 37°C tap water for 50 hours before carrying out BFS test, according to BS EN ISO 1567: 2001. BFS test was carried out using a tensile-testing machine (Lloyd LRX, Lloyd instruments Ltd (Figure.1 b, with a x-head speed of 1mm/min. ONE-WAY ANOVA analysis and TUKEY’S comparison were carried out (MINITAB. The temperature within the curing baths and inside of curing resin was evaluated by using a thermocouple. Results: BFS of Powder/liquid ratio of 1.5:1 is significantly lower than the other four ratios. Among the last four ratios, 2.5:1 was the strongest one although the difference was not significant. BFS of the plain type of PMMA is significantly higher than the veined type.• BFS of conventionally packed PMMA discs was greater than the injectional packed ones and the difference is significant. Water bath cured resin showed a significant higher BFS compared with dry heat curing. • Changing the curing time in the dry heat bath from 7h @ 75º C and 2hrs @ 95º C to 5hrs @ 75º C and 3hrs @ 95º C and then 2hrs @ 95º C improves BFS of PMMA. In the water bath the trend is identical although the difference is not significant. Analysis of the temperature climb and hold within the curing bathes showed a consistent performance with the water bath irrespective the number of the flasks being cured. Meanwhile, the dry heat bath showed very inconsistent results. Conclusion: 1. Type of resin, packing procedure and processing variables can have major effect on BFS of PMMA. 2. Using plain resin, conventional packing, water bath curing with two hours at 95 ºC are recommended conditions.

T Nejatiant

2005-10-01

216

Treatment of spent ion-exchange resins  

International Nuclear Information System (INIS)

After the useful lifetime of ion-exchange resins is over, they must be discharged and treated for safe storage and/or disposal. Pretreatement of these resins guarantees safe interim storage or conversion of the resin-slurry into a chemical or physical form suitable for immobilization, followed by the real conditioning steps. Today conditioning of resins is done by three main procedures: cementation, bituminization and embedding in polymers. Based on the results of an IAEA co-ordinated research programme on the Treatment of Spent Ion-Exchange Resins which commenced in 1979, these procedures are described briefly and a survey of recent developments is made. As an example of practical application, situations in Sweden and France are described in which cement, bitumen and polymers have been used for many years for immobilization of nuclear reactor wastes including spent resins. (author)

217

Removal of cyanocobalamine from aqueous solution using mesoporous activated carbon  

Energy Technology Data Exchange (ETDEWEB)

The adsorption of cyanocobalamine was studied using coal-based mesoporous activated carbon (AC). The ACs tested showed a comparable pore volume, around 0.5 cm{sup 3} g{sup -1}, but different contribution of mesopores ranging from 0.53 to 0.82 cm{sup 3} g{sup -1}. The adsorption of cyanocobalamine was carried out in slightly alkaline solution in static conditions. Three kinetic models including a first-order Lagergren model, a pseudo-second-order model, and an intraparticle diffusion model were applied to describe the kinetics and mechanism of adsorption. The adsorption of cyanocobalamine on mesoporous carbons followed the pseudo-second-order model. The diffusion of cyanocobalamine molecule within smaller mesopores was identified to be the rate-limiting step. The analysis of adsorption equilibrium data indicates that the adsorption of cyanocobalamine better fits the Langmuir equation than the Freundlich equation. The Langmuir adsorption capacity of the carbon is strongly related to the degree of mesoporosity development. Among ACs tested, the carbon with the highest mesopore volume and mesopore width of 10-50 nm shows the greater ability to remove cyanocobalamine from aqueous solution. The effect of pore-size distribution on the kinetics and mechanism of adsorption has been discussed.

Lorenc-Grabowska, E.; Gryglewicz, G. [Wroclaw Technical University, Wroclaw (Poland). Faculty of Chemistry

2007-07-01

218

Volumetric polymerization shrinkage of contemporary composite resins  

OpenAIRE

The polymerization shrinkage of composite resins may affect negatively the clinical outcome of the restoration. Extensive research has been carried out to develop new formulations of composite resins in order to provide good handling characteristics and some dimensional stability during polymerization. The purpose of this study was to analyze, in vitro, the magnitude of the volumetric polymerization shrinkage of 7 contemporary composite resins (Definite, Suprafill, SureFil, Filtek Z250, Fill ...

Halim Nagem Filho; Haline Drumond Nagem; Paulo Afonso Silveira Francisconi; Eduardo Batista Franco; Rafael Francisco Lia Mondelli; Kennedy Queiroz Coutinho

2007-01-01

219

Modified BET Equation for Determination of Micropore Pore Volume and Mesopore Surface Area in Microporous-Mesoporous Solids.  

Czech Academy of Sciences Publication Activity Database

Edinburgh : University of Edinburgh, 2008, s. 103. ISBN N. [8th International Symposium on the Characterisation of Porous Solids. Edinburgh (GB), 10.06.2008-13.06.2008] R&D Projects: GA AV ?R IAA4072404; GA AV ?R KAN400720701 Institutional research plan: CEZ:AV0Z40720504 Keywords : microporous-mesoporous solids * mesopore surface area Subject RIV: CF - Physical ; Theoretical Chemistry

Šolcová, Olga; Mat?jová, Lenka; Hudec, P.; Schneider, Petr

220

Advanced resin systems for graphite epoxy composites  

Science.gov (United States)

The value of resin/carbon fiber composites as lightweight structures for aircraft and other vehicle applications is dependent on many properties: environmental stability, strength, toughness, resistance to burning, smoke produced when burning, raw material costs, and complexity of processing. A number of woven carbon fiber and epoxy resin composites were made. The epoxy resin was commercially available tetraglycidylmethylene dianiline. In addition, composites were made using epoxy resin modified with amine and carboxyl terminated butadiene acrylonitrile copolymer. Strength and toughness in flexure as well as oxygen index flammability and NBS smoke chamber tests of the composites are reported.

Gilwee, W. J.; Jayarajan, A.

1980-01-01

221

Graphite composites with advanced resin matrices  

Science.gov (United States)

The effect of processing variables on the flammability and mechanical properties for state-of-the-art and advanced resin matrices for graphite composites were studied. Resin matrices which were evaluated included state-of-the-art epoxy, phenolic-novolac, phenolic-xylok, two types of bismaleimides, benzyl, polyethersulfone, and poly(p-phenylene sulfone). Comparable flammability and thermochemical data on graphite-reinforced laminates prepared with these resin matrices are presented, and the relationship of some of these properties to the anaerobic char yield of the resins is described.

Kourtides, D. A.

1980-01-01

222

Novel silica-based ion exchange resin  

Energy Technology Data Exchange (ETDEWEB)

Eichrom`s highly successful Diphonixo resin resembles a conventional ion exchange resin in its use of sulfonic acid ligands on a styrene- divinylbenzene matrix. Diphonix resin exhibits rapid exchange kinetics that allow economical operation of ion exchange systems. Unlike conventional resins, Diphonix resin contains chelating ligands that are diphosphonic acid groups that recognize and remove the targeted metals and reject the more common elements such as sodium, calcium and magnesium. This latter property makes Diphonix ideal for many industrial scale applications, including those involving waste treatment. For treatment of low-level, transuranic (TRU) and high- level radioactive wastes, Diphonix`s polystyrene backbone hinders its application due to radiolytic stability of the carbon-hydrogen bonds and lack of compatibility with expected vitrification schemes. Polystyrene-based Diphonix is approximately 60% carbon- hydrogen. In response to an identified need within the Department of Energy for a resin with the positive attributes of Diphonix that also exhibits greater radiolytic stability and final waste form compatibility, Eichrom has successfully developed a new, silica-based resin version of Diphonix. Target application for this new resin is for use in environmental restoration and waste management situations involving the processing of low-level, transuranic and high-level radioactive wastes. The resin can also be used for processing liquid mixed waste (waste that contains low level radioactivity and hazardous constituents) including mixed wastes contaminated with organic compounds. Silica-based Diphonix is only 10% carbon-hydrogen, with the bulk of the matrix silica.

NONE

1997-11-01

223

Method of decomposing ion exchange resin waste  

International Nuclear Information System (INIS)

Purpose: To shorten the time required for decomposing treatment and obtain high decomposing rate. Constitution: Granular ion exchange resin wastes are at first finely pulverized in the pulverizing step at the former stage. Then, granulated ion exchange resins are introduced to the oxidative decomposing step at the latter stage in which an oxidizer for hydrogen peroxide and iron and copper ion catalyst are added to oxidatively decompose ion exchange resin wastes. The consumption of hydrogen peroxide can be economized greatly by the powerization of the resin and the decomposing time can also be shortened. Further, no substantial foaming is generated in the course of the oxidative decomposing step. (Sekiya, K.)

224

Synthesis of ordered mesoporous U{sub 3}O{sub 8} by a nanocasting route  

Energy Technology Data Exchange (ETDEWEB)

Ordered mesoporous U{sub 3}O{sub 8} has been synthesized by a nanocasting route using mesoporous silica (KIT-6 and SBA-15) as templates and characterized by using XRD, SEM and nitrogen adsorption/desorption techniques.

Zhao, Ran; Wang, Lin; Gu, Zhan-Jun; Yuan, Li-Yong; Xiao, Cheng-Liang; Zhao, Yu-Liang; Shi, Wei-Qun [Institute of High Energy Physics, Beijing (China). Key Laboratory of Nuclear Radiation and Nuclear Energy Technology; Chai, Zhi-Fang [Institute of High Energy Physics, Beijing (China). Key Laboratory of Nuclear Radiation and Nuclear Energy Technology; Soochow Univ., Suzhou (China). School of Radiological and Interdisciplinary Sciences

2014-11-01

225

Single crystal particles of a mesoporous mixed transition metal oxide with a wormhole structure.  

Science.gov (United States)

A new type of mesoporous mixed transition metal oxide of Nb and Ta (NbTa-TIT-1) has been prepared through a two-step calcination, which consists of single crystal particles with wormhole mesoporous structure. PMID:12240191

Lee, B; Lu, D; Kondo, J N; Domen, K

2001-10-21

226

High-performance, single-layer antireflective optical coatings comprising mesoporous silica nanoparticles  

OpenAIRE

Mesoporous silica nanoparticles are used to fabricate antireflectance coatings on glass substrates. The combination of mesoporous silica nanoparticles in conjunction with a suitable binder material allows mechanically robust single layer coatings with a reflectance

Moghal, J.; Kobler, J.; Sauer, J.; Best, J.; Gardener, M.; Watt, Aar; Wakefield, G.

2012-01-01

227

Mesoporous hexagonal Co3O4 for high performance lithium ion batteries  

Science.gov (United States)

Mesoporous Co3O4 nanoplates were successfully prepared by the conversion of hexagonal ?-Co(OH)2 nanoplates. TEM, HRTEM and N2 sorption analysis confirmed the facet crystal structure and inner mesoporous architecture. When applied as anode materials for lithium storage in lithium ion batteries, mesoporous Co3O4 nanocrystals delivered a high specific capacity. At 10 C current rate, as-prepared mesoporous Co3O4 nanoplates delivered a specific capacity of 1203 mAh/g at first cycle and after 200 cycles it can still maintain a satisfied value (330 mAh/g). From ex-situ TEM, SAED and FESEM observation, it was found that mesoporous Co3O4 nanoplates were reduced to Li2O and Co during the discharge process and re-oxidised without losing the mesoporous structure during charge process. Even after 100 cycles, mesoporous Co3O4 crystals still preserved their pristine hexagonal shape and mesoporous nanostructure.

Su, Dawei; Xie, Xiuqiang; Munroe, Paul; Dou, Shixue; Wang, Guoxiu

2014-10-01

228

Spin Depolarization of Muonium in Mesoporous Silica  

Science.gov (United States)

We report muon spin rotation/relaxation measurements of muonium in mesoporous silica (SBA-15) with a high specific surface area of 600 m2/g. Up to 70 percent of the incoming muons form muonium and escape efficiently into the open pores at all temperatures between 3 and 300K. We present evidence that the interaction with the silica surfaces involves both spin exchange and a transition to a diamagnetic state, possibly due to dangling bonds on the surface. At very low temperatures, below 20K, the interaction between muonium and the silica surfaces is suppressed due to a He film coating the surfaces. These results indicate that it should be possible to use muonium to probe the surfaces of uncapped nanoparticles supported in silica.

Dehn, M. H.; Arseneau, D. J.; Bridges, M. D.; Buck, T.; Cortie, D. L.; Cottrell, S. P.; Fleming, D. G.; Kelly, J. A.; MacFarlane, W. A.; MacLachlan, M. J.; Morris, G. D.; McKenzie, I.; Xiao, J.; Kiefl, R. F.

2014-12-01

229

Plutonium sorption to nanocast mesoporous carbon  

Energy Technology Data Exchange (ETDEWEB)

Nanocast ordered mesoporous carbons are attractive as sorbents because of their extremely high surface areas and large pore volumes. This paper compares Pu uptake, added as Pu(VI), to both untreated and chemically oxidized CMK-(carbon molecular sieves from KAIST) type mesoporous carbon with that to a commercial amorphous activated carbon. The CMK was synthesized via nanocasting by using cubic ordered mesoporous silica KIT-6 as a hard template, and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption. A portion of the CMK was oxidized by treatment with nitric acid, and will be called OX CMK. The three carbon powders have similar particle morphology, and high BET surface areas. The activated carbon is disordered, while the CMK materials show large domains of ordered cubic mesostructure. The CMK material seems to have more oxygen-containing functional groups than the activated carbon, and the oxidation of the CMK increased the density of these groups, especially - COOH, thus lowering the point of zero charge (PZC) of the material. Batch studies of all 3 materials with plutonium solutions, in a 0.1 M NaClO{sub 4} matrix were performed to investigate pH dependence, sorption kinetics, Pu uptake capacities, competition with ethylenediaminetetraacetic acid (EDTA) in solution, and Pu desorption. Both CMK materials demonstrated high Pu sorption from solutions of pH 3 or greater, and the oxidized CMK also showed high sorption from pH 2 solutions. The activated carbon bound less Pu, and at a much slower rate than CMK. All other batch experiments were carried out in pH 4 solutions. The Pu uptake from low-concentration solutions was faster for the oxidized CMK than for untreated CMK, but in more concentrated samples (? 250 ?M Pu), the Pu uptake kinetics and apparent capacity were the same for oxidized and untreated CMK. The 23-h Pu uptake capacity of the CMK materials was measured to be at least 58 ± 5 mg {sup 239}Pu per g CMK carbon, compared to 12 ± 5 mg {sup 239}Pu per g activated carbon. The presence of EDTA in solution decreased the Pu sorption to CMK. Desorption from all samples occurred in 1 M HClO{sub 4}, usually within 24 h. The Pu interaction with the carbon surface was also probed via X-ray absorption spectroscopy (XAS) on the Pu L{sub III} absorption edge. Spectral fits of the X-ray absorption near-edge structure (XANES) data collected on both types of CMK samples showed that Pu(VI) was reduced to Pu(IV) at the carbon surface. The high affinity of mesoporous carbon for Pu, and the spontaneous reduction of Pu(VI) or Pu(V) to Pu(IV) at these carbon surfaces could be valuable for a variety of applications. (orig.)

Parsons-Moss, Tashi; Wang, Deborah; Jones, Stephen; Olive, Daniel; Nitsche, Heino [California Univ., Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Nuclear Science Div.; Tueysuez, Harun [Lawrence Berkeley National Laboratory, Berkeley, CA (United States). Nuclear Science Div.; Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany)

2014-09-01

230

Plutonium sorption to nanocast mesoporous carbon  

International Nuclear Information System (INIS)

Nanocast ordered mesoporous carbons are attractive as sorbents because of their extremely high surface areas and large pore volumes. This paper compares Pu uptake, added as Pu(VI), to both untreated and chemically oxidized CMK-(carbon molecular sieves from KAIST) type mesoporous carbon with that to a commercial amorphous activated carbon. The CMK was synthesized via nanocasting by using cubic ordered mesoporous silica KIT-6 as a hard template, and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption. A portion of the CMK was oxidized by treatment with nitric acid, and will be called OX CMK. The three carbon powders have similar particle morphology, and high BET surface areas. The activated carbon is disordered, while the CMK materials show large domains of ordered cubic mesostructure. The CMK material seems to have more oxygen-containing functional groups than the activated carbon, and the oxidation of the CMK increased the density of these groups, especially - COOH, thus lowering the point of zero charge (PZC) of the material. Batch studies of all 3 materials with plutonium solutions, in a 0.1 M NaClO4 matrix were performed to investigate pH dependence, sorption kinetics, Pu uptake capacities, competition with ethylenediaminetetraacetic acid (EDTA) in solution, and Pu desorption. Both CMK materials demonstrated high Pu sorption from solutions of pH 3 or greater, and the oxidized CMK also showed high sorption from pH 2 solutions. The activated carbon bound less Pu, and at a much slower rate than CMK. All other batch experiments were carried out in pH 4 solutions. The Pu uptake from low-concentration solutions was faster for the oxidized CMK than for untreated CMK, but in more concentrated samples (? 250 ?M Pu), the Pu uptake kinetics and apparent capacity were the same for oxidized and untreated CMK. The 23-h Pu uptake capacity of the CMK materials was measured to be at least 58 ± 5 mg 239Pu per g CMK carbon, compared to 12 ± 5 mg 239Pu per g activated carbon. The presence of EDTA in solution decreased the Pu sorption to CMK. Desorption from all samples occurred in 1 M HClO4, usually within 24 h. The Pu interaction with the carbon surface was also probed via X-ray absorption spectroscopy (XAS) on the Pu LIII absorption edge. Spectral fits of the X-ray absorption near-edge structure (XANES) data collected on both types of CMK samples showed that Pu(VI) was reduced to Pu(IV) at the carbon surface. The high affinity of mesoporous carbon for Pu, and the spontaneous reduction of Pu(VI) or Pu(V) to Pu(IV) at these carbon surfaces could be valuable for a variety of applications. (orig.)

231

40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).  

Science.gov (United States)

...2010-07-01 2010-07-01 false Epoxy resin containing phosphorus (generic...Chemical Substances § 721.2752 Epoxy resin containing phosphorus (generic...substance identified generically as an epoxy resin containing phosphorus...

2010-07-01

232

40 CFR 721.3135 - Phosphorous modified epoxy resin (generic).  

Science.gov (United States)

... false Phosphorous modified epoxy resin (generic). 721.3135 Section...721.3135 Phosphorous modified epoxy resin (generic). (a) Chemical...generically as a phosphorous modified epoxy resin (PMNs P-00-992 and...

2010-07-01

233

40 CFR 721.2755 - Cycloaliphatic epoxy resin (generic).  

Science.gov (United States)

...2010-07-01 false Cycloaliphatic epoxy resin (generic). 721.2755 Section... § 721.2755 Cycloaliphatic epoxy resin (generic). (a) Chemical...identified generically as cycloaliphatic epoxy resin (PMN P-98-105) is...

2010-07-01

234

75 FR 67105 - Granular Polytetrafluoroethylene Resin From Italy and Japan  

Science.gov (United States)

...Granular Polytetrafluoroethylene Resin From Italy and Japan AGENCY: United States International...granular polytetrafluoroethylene resin from Italy and Japan...granular polytetrafluoroethylene resin from Italy and Japan would be likely to lead to...

2010-11-01

235

21 CFR 177.2410 - Phenolic resins in molded articles.  

Science.gov (United States)

... true Phenolic resins in molded articles. 177.2410 Section 177.2410...Substances for Use Only as Components of Articles Intended for Repeated Use § 177.2410 Phenolic resins in molded articles. Phenolic resins identified...

2010-04-01

236

21 CFR 173.5 - Acrylate-acrylamide resins.  

Science.gov (United States)

...3 2010-04-01 2009-04-01 true Acrylate-acrylamide resins. 173.5 Section 173...Polymer Adjuvants for Food Treatment § 173.5 Acrylate-acrylamide resins. Acrylate-acrylamide resins may be safely used in...

2010-04-01

237

40 CFR 721.5762 - Aromatic aldehyde phenolic resin (generic).  

Science.gov (United States)

...2010-07-01 false Aromatic aldehyde phenolic resin (generic). 721.5762 Section...721.5762 Aromatic aldehyde phenolic resin (generic). (a) Chemical...generically as aromatic aldehyde phenolic resin (PMN P-01-573) is...

2010-07-01

238

40 CFR 721.5905 - Modified phenolic resin (generic).  

Science.gov (United States)

...2010-07-01 false Modified phenolic resin (generic). 721.5905 Section...Substances § 721.5905 Modified phenolic resin (generic). (a) Chemical...identified generically as a modified phenolic resin (PMN P-01-441) is...

2010-07-01

239

40 CFR 721.5908 - Modified phenolic resin (generic).  

Science.gov (United States)

...2010-07-01 false Modified phenolic resin (generic). 721.5908 Section...Substances § 721.5908 Modified phenolic resin (generic). (a) Chemical...identified generically as modified phenolic resin (PMN P-01-561) is...

2010-07-01

240

21 CFR 872.3770 - Temporary crown and bridge resin.  

Science.gov (United States)

...2010-04-01 false Temporary crown and bridge resin. 872.3770 Section 872.3770...Devices § 872.3770 Temporary crown and bridge resin. (a) Identification. A temporary crown and bridge resin is a device composed of a...

2010-04-01

241

21 CFR 872.3300 - Hydrophilic resin coating for dentures.  

Science.gov (United States)

...2010-04-01 false Hydrophilic resin coating for dentures. 872.3300 Section...Devices § 872.3300 Hydrophilic resin coating for dentures. (a) Identification. A hydrophilic resin coating for dentures is a device that...

2010-04-01

242

21 CFR 872.3310 - Coating material for resin fillings.  

Science.gov (United States)

...2010-04-01 2010-04-01 false Coating material for resin fillings. 872... Prosthetic Devices § 872.3310 Coating material for resin fillings. (a) Identification. A coating material for resin fillings is a...

2010-04-01

243

Enhanced retention of aqueous transition metals in mesoporous silica  

Science.gov (United States)

Mesoporosity (2-50 nm diameter pores) is abundant within grain coatings and primary silicate minerals in natural environments. Mesopores often contribute significantly to total specific surface area and act as gateways for the transport of subsurface solutes, including nutrients and contaminants, between mineral surfaces and ambient fluids. However, the physiochemical mechanisms of sorption and transport within mesopores cannot be assumed to be the same as for macropores (>50 nm), because of confinement-induced changes in water properties, the structure of electrical double layers, solvation shells and dehydration rates of aquo ions, and the charge and reactive site densities of mineral surfaces. Despite the ubiquity of confined spaces in natural and industrial porous media, few studies have examined the molecular-scale mechanisms and geochemical reactions controlling meso-confinement phenomena in environmentally relevant materials. We conducted batch Zn sorption experiments using synthetic, controlled pore-size (i.e., 7.5-300 nm), metal-oxide beads as model geologic substrates. Comparison of Zn adsorbed onto macroporous and mesoporous silica beads indicates Zn adsorption capacity is increased in mesopores when normalized to surface area. In the presence of a background electrolyte (i.e., NaCl), Zn sorption capacity to macroporous silica is reduced; however, no significant difference in Zn sorption capacity on mesoporous silica was observed between the presence and absence of a background electrolyte. The effect of competing cations is indirect evidence that mesopores promote inner-sphere complexation and reduce outer-sphere complexation. EXAFS characterization of adsorbed zinc to macroporous silica matches that reported for low Zn coverages on silica (Roberts et al., JCIS, 2003), whereas a different spectrum is observed for the mesoporous case. Shell-by-shell fitting indicates that Zn is dominantly in octahedral coordination in macropores, as opposed to tetrahedral coordination in mesopores. The difference in Zn coordination may be the result of complexation at different surface sites and/or the precipitation of a zinc silicate in mesopores. Confinement effects within mesopores represent an emerging frontier in aqueous geochemistry, and the pursuit of a mechanistic understanding will contribute to more accurate models of reactive transport in porous media.

Nelson, J.; Bargar, J.; Brown, G. E.; Maher, K.

2013-12-01

244

Gyroidal mesoporous multifunctional nanocomposites via atomic layer deposition  

Science.gov (United States)

We demonstrate the preparation of rationally designed, multifunctional, monolithic and periodically ordered mesoporous core-shell nanocomposites with tunable structural characteristics. Three-dimensionally (3D) co-continuous gyroidal mesoporous polymer monoliths are fabricated from a solution-based triblock terpolymer-resol co-assembly and used as the functional templates for the fabrication of free-standing core-shell carbon-titania composites using atomic layer deposition (ALD). The deposition depth into the torturous gyroidal nanonetwork is investigated as a function of ALD conditions and the resulting composites are submitted to different thermal treatments. Results suggest that ALD can homogenously coat mesoporous templates with well defined pore sizes below 50 nm and thicknesses above 10 ?m. Structural tunability like titania shell thickness and pore size control is demonstrated. The ordered nanocomposites exhibit triple functionality; a 3D continuous conductive carbon core that is coated with a crystalline titania shell that in turn is in contact with a 3D continuous mesopore network in a compact monolithic architecture. This materials design is of interest for applications including energy conversion and storage. Gyroidal mesoporous titania monoliths can be obtained through simultaneous titania crystallization and template removal in air.We demonstrate the preparation of rationally designed, multifunctional, monolithic and periodically ordered mesoporous core-shell nanocomposites with tunable structural characteristics. Three-dimensionally (3D) co-continuous gyroidal mesoporous polymer monoliths are fabricated from a solution-based triblock terpolymer-resol co-assembly and used as the functional templates for the fabrication of free-standing core-shell carbon-titania composites using atomic layer deposition (ALD). The deposition depth into the torturous gyroidal nanonetwork is investigated as a function of ALD conditions and the resulting composites are submitted to different thermal treatments. Results suggest that ALD can homogenously coat mesoporous templates with well defined pore sizes below 50 nm and thicknesses above 10 ?m. Structural tunability like titania shell thickness and pore size control is demonstrated. The ordered nanocomposites exhibit triple functionality; a 3D continuous conductive carbon core that is coated with a crystalline titania shell that in turn is in contact with a 3D continuous mesopore network in a compact monolithic architecture. This materials design is of interest for applications including energy conversion and storage. Gyroidal mesoporous titania monoliths can be obtained through simultaneous titania crystallization and template removal in air. Electronic supplementary information (ESI) available: Photographs of flexible templates and the Beneq ALD reactor indicating the different sample positioning. See DOI: 10.1039/c4nr01948b

Werner, Jörg G.; Scherer, Maik R. J.; Steiner, Ullrich; Wiesner, Ulrich

2014-07-01

245

Adsorption and release of biocides with mesoporous silica nanoparticles  

Science.gov (United States)

In this proof-of-concept study, an agricultural biocide (imidacloprid) was effectively loaded into the mesoporous silica nanoparticles (MSNs) with different pore sizes, morphologies and mesoporous structures for termite control. This resulted in nanoparticles with a large surface area, tunable pore diameter and small particle size, which are ideal carriers for adsorption and controlled release of imidacloprid. The effect of pore size, surface area and mesoporous structure on uptake and release of imidacloprid was systematically studied. It was found that the adsorption amount and release profile of imidacloprid were dependent on the type of mesoporous structure and surface area of particles. Specifically, MCM-48 type mesoporous silica nanoparticles with a three dimensional (3D) open network structure and high surface area displayed the highest adsorption capacity compared to other types of silica nanoparticles. Release of imidacloprid from these nanoparticles was found to be controlled over 48 hours. Finally, in vivo laboratory testing on termite control proved the efficacy of these nanoparticles as delivery carriers for biopesticides. We believe that the present study will contribute to the design of more effective controlled and targeted delivery for other biomolecules.In this proof-of-concept study, an agricultural biocide (imidacloprid) was effectively loaded into the mesoporous silica nanoparticles (MSNs) with different pore sizes, morphologies and mesoporous structures for termite control. This resulted in nanoparticles with a large surface area, tunable pore diameter and small particle size, which are ideal carriers for adsorption and controlled release of imidacloprid. The effect of pore size, surface area and mesoporous structure on uptake and release of imidacloprid was systematically studied. It was found that the adsorption amount and release profile of imidacloprid were dependent on the type of mesoporous structure and surface area of particles. Specifically, MCM-48 type mesoporous silica nanoparticles with a three dimensional (3D) open network structure and high surface area displayed the highest adsorption capacity compared to other types of silica nanoparticles. Release of imidacloprid from these nanoparticles was found to be controlled over 48 hours. Finally, in vivo laboratory testing on termite control proved the efficacy of these nanoparticles as delivery carriers for biopesticides. We believe that the present study will contribute to the design of more effective controlled and targeted delivery for other biomolecules. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11691j

Popat, Amirali; Liu, Jian; Hu, Qiuhong; Kennedy, Michael; Peters, Brenton; Lu, Gao Qing (Max); Qiao, Shi Zhang

2012-01-01

246

Measurement of Uptake and Release Capacities of Mesoporous Silica Nanoparticles Enabled by Nanovalve Gates  

OpenAIRE

The uptake and release capacities of mesoporous silica particles are measured on nanovalve-gated stimulated release systems, using a water soluble biological stain, Hoechst 33342, as the cargo model. Five different types of mesoporous silica nanoparticles: 2D-hexagonal MCM-41, swollen pore MCM-41, rod-like MCM-41, hollow mesoporous nanoparticles and radial mesoporous nanoparticles are studied and compared. Solid silica nanoparticles are used as the control. Because of the presence of the nano...

Li, Zongxi; Likoko, Jeff Nyalosaso; Hwang, Angela A.; Ferris, Daniel P.; Yang, Sui; Derrien, Gaelle; Charnay, Clarence; Durand, Jean-olivier; Zink, Jeffrey I.

2011-01-01

247

Process for the manufacture of an ionising source of radiation  

International Nuclear Information System (INIS)

The source of radiation is used to calibrate a multi-channel analyser. It consists of a solid molecular solution of the isotope Mn 54, Fe 59, P 32 or Co 60 in phenol formaldehyde resin of the resol type or novolak type. The porous intermediate product is ground to powder, brought to the source in the final form and hardened. (DG)

248

Ion exchange on phenolic ion exchangers  

International Nuclear Information System (INIS)

Equilibrium of alkali metal ion exchange in phenol-formaldehyde resins (PFR) with spherical form granules is studied. Concentration coefficients of alkali metal ions (Cs+-Na+, Cs+-Rb+ and others) equilibrium in PRF are determined. It is shown that PRF selectivity to rubidium and cesium ions is essentially higher than that of sulfophenol and nitrated sulfocationites within whole ratio range

249

Synthesis and Characterizations of Melamine-Based Epoxy Resins  

OpenAIRE

A new, easy and cost-effective synthetic procedure for the preparation of thermosetting melamine-based epoxy resins is reported. By this innovative synthetic method, different kinds of resins can be obtained just by mixing the reagents in the presence of a catalyst without solvent and with mild curing conditions. Two types of resins were synthesized using melamine and a glycidyl derivative (resins I) or by adding a silane derivative (resin II). The resins were characterized by means of chemic...

Raffaele Cioffi; Michelina Catauro; Francesco Colangelo; Claudio Ferone; Fabio Borbone; Oreste Tarallo; Giuseppina Roviello; Laura Ricciotti

2013-01-01

250

Polyimide Resins Resist Extreme Temperatures  

Science.gov (United States)

Spacecraft and aerospace engines share a common threat: high temperature. The temperatures experienced during atmospheric reentry can reach over 2,000 F, and the temperatures in rocket engines can reach well over 5,000 F. To combat the high temperatures in aerospace applications, Dr. Ruth Pater of Langley Research Center developed RP-46, a polyimide resin capable of withstanding the most brutal temperatures. The composite material can push the service temperature to the limits of organic materials. Designed as an environmentally friendly alternative to other high-temperature resins, the RP-46 polyimide resin system was awarded a 1992 "R&D 100" award, named a "2001 NASA Technology of the Year," and later, due to its success as a spinoff technology, "2004 NASA Commercial Invention of the Year." The technology s commercial success also led to its winning the Langley s "Paul F. Holloway Technology Transfer Award" as well as "Richard T. Whitcom Aerospace Technology Transfer Award" both for 2004. RP-46 is relatively inexpensive and it can be readily processed for use as an adhesive, composite, resin molding, coating, foam, or film. Its composite materials can be used in temperatures ranging from minus 150 F to 2,300 F. No other organic materials are known to be capable of such wide range and extreme high-temperature applications. In addition to answering the call for environmentally conscious high-temperature materials, RP-46 provides a slew of additional advantages: It is extremely lightweight (less than half the weight of aluminum), chemical and moisture resistant, strong, and flexible. Pater also developed a similar technology, RP-50, using many of the same methods she used with RP-46, and very similar in composition to RP-46 in terms of its thermal capacity and chemical construction, but it has different applications, as this material is a coating as opposed to a buildable composite. A NASA license for use of this material outside of the Space Agency as well as additional government-funded testing proved that RP-46 is even more exceptional than originally thought.

2009-01-01

251

Spectroscopic studies of petroleum resins  

Energy Technology Data Exchange (ETDEWEB)

Resin fractions containing heteroatoms obtained from deasphaltened oils of petroleum residues (500/sup 0/C+) of Bombay High (BH) and Gujrat Crude Mix (GCM) have been separated into acidic, basic and neutral Lewis base (NLB) types employing chromatographic methods. Ultimate compositions of these fractions have been determined for deducing the average molecular formulae. Infrared spectroscopy has been employed for assigning various heteroatomic functional groups and estimating compound types. The distribution of various types of carbon (relative as well as atomic) and hydrogen has been computed from /sup 13//sub C-/ and /sup 1/H-NMR spectra of these subfractions.

Sarowha, S.L.S.; Singh, I.D.

1988-01-01

252

Spectroscopic studies of petroleum resins  

International Nuclear Information System (INIS)

Resin fractions containing heteroatoms obtained from deasphaltened oils of petroleum residues (5000C+) of Bombay High (BH) and Gujrat Crude Mix (GCM) have been separated into acidic, basic and neutral Lewis base (NLB) types employing chromatographic methods. Ultimate compositions of these fractions have been determined for deducing the average molecular formulae. Infrared spectroscopy has been employed for assigning various heteroatomic functional groups and estimating compound types. The distribution of various types of carbon (relative as well as atomic) and hydrogen has been computed from /sup 13//sub C-/ and /sup 1/H-NMR spectra of these subfractions

253

Metal containing mesoporous silica materials: Synthesis, characterization, and applications  

Science.gov (United States)

The work presented here comprises the development of a new route for the incorporation of transition metals (TM = Mn, V, Cr) into the pores of mesoporous silica materials, the characterization, and the applications of the resulting materials. The mesoporous silica material used in this work is of the M41S family, known as MCM-48. The first part of the work is going to be focused on in the incorporation of manganese species. Characterization of the resulting materials will be sub-divided in two major parts: (1) Structural and textural properties and (2) Analysis of the Mn oxidation state, coordination and location in the mesoporous host. The process of incorporation of Mn into the mesoporous materials takes place by using high valence metal precursor anions. Then a mechanism to describe the process of loading the Mn species will be proposed. The method developed makes possible the incorporation of high loadings of transition metals while maintaining the properties of the host material, MCM-48. In the second part of the research the synthesis method developed in the first part is used to incorporate other transition metals such as vanadium and chromium. As in the first part, the nature of the TM species is investigated and their catalytic application in oxidation of styrene is also studied. The materials show good activity towards styrene oxidation with conversions as high as 100%. The catalysts can also be recycled without significant loss of activity. Finally, the last part of the research deals with the incorporation of tin oxide into mesoporous silica. A similar approach to the one used for transition metals was used to load tin in MCM-48, however, discrete tin oxide nanoparticles were formed on the surface of the mesoporous structure rather than inside of the pores. The sensing properties towards reducing gases such as hydrogen of these materials were tested, and the Sn containing mesoporous silica show promising properties for gas sensing applications.

Gomez, Sinue

254

Properties of the Carboxylate ion exchange resins; Karboxylatjonbytarmassans egenskaper  

Energy Technology Data Exchange (ETDEWEB)

Weakly acidic, carboxylic resin has been selected, together with strong base anion resins, for water purification at the Forsmark 1 and 2 reactors. For the strong (but not the weak) ion exchange resin the Nuclear Power Inspectorate has given permission to dispose the spent resins in the SFR 1 (the Final Repository for Radioactive Operational Waste). This report gives a review of the carboxylic resins and comes to the conclusion that the resins are very stable and that there should not exist any risks for increased leaching of radionuclides from SFR 1 if these resins are disposed (compared to the strong resins)

Allard, Bert; Dario, Maarten [Oerebro Univ. (Sweden); Boren, Hans [Linkoepings Univ. (Sweden); Torstenfelt, Boerje [Swedpower, Stockholm (Sweden); Puigdomenech, Ignasi; Johansson, Claes [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)

2002-09-01

255

Surface preparations for metal frameworks of composite resin veneered prostheses made with an adhesive opaque resin.  

Science.gov (United States)

Bond strengths of a laboratory developed light-cured composite resin to dental casting alloys were evaluated with a new adhesive opaque resin. The metal specimens were type III gold, nickel-chromium, and cobalt-chromium alloys, while the surface treatments for bonding were heating, Sn plating, and ion coating. The cast metal specimens were "particle blasted" with aluminum oxide and were surface treated. Adhesive 4-META/MMA-TBB opaque resin was applied and a light-cured composite resin was placed over the opaque layer. The prepared specimens were thermocycled in water and shear bond strengths were recorded. The light-cured composite resin was bonded strongly to heated or Sn-plated type III alloy with 4-META/MMA-TBB opaque resin. Copper ion coating in a sputter coater was effective for all three alloys, with only slightly diminished bond strengths. These methods were satisfactory for making composite resin veneered prostheses. PMID:1941662

Matsumura, H; Kawahara, M; Tanaka, T; Atsuta, M

1991-07-01

256

Researches concerning the purolite resin assimilation for use within the uranium separation - concentration resin in pulp process  

International Nuclear Information System (INIS)

New strong base anionite resins manufactures by the Purolite Company were studied comparing with the older AM resin, for U6+ separation concentration from model solutions. Loading capacities for U6+, were established using both resins, A 500 and A 600 respectively, followed by the study of the loading capacity variation related to the recycling number. Mechanical resistance determination was performed for SHA 600 and AM resins, showing superior characteristics for these resins and enabling their use in 'Resin In Pulp' process. (authors)

257

Treatment of spent ion-exchange resins  

International Nuclear Information System (INIS)

Information is given on the process of incorporating spent ion-exchange resins into bitumen in one step, continuously and in a closed technology. Examinations and experiments were carried out in order to obtain information on the behaviour of the starting materials and products of the planned process and technology. Results show that the commercial resins Varion KS and Varion AT-660 do not suffer from thermal decomposition at 800C. Nuclear power plant grade resins, however, are decomposing at this temperature. The spent resins and the bitumen applied do not suffer from any notable thermal decomposition at the planned, maximum 1600C temperature of the incorporation. Thermal stability of the cation-exchange resins is higher than that of the anion-exchange resins. Water content of the products obtained by incorporation carried out at 1600C, in a batchwise operation, fluctuated independently of the original water content of the resins and of the specific quantity of the incorporated resin - between 2 and 3%

258

Epoxidation of linseed oil-Alkyd resins  

International Nuclear Information System (INIS)

Three types of different linseed oil-alkyd resin ( Alk (I), Alk (II), and Alk (III) ) were prepared with the calculated amounts of mono glycerides and adipic acid (1:1, 1:2, and 2:1 Eq.Wt) respectively via monoglyceride method. The obtained alkyd resins were epoxidized via reaction with the calculated quantities of peracetic acid, which was prepared by the reaction of acetic anhydride with H2O2. Epoxidation occurred with the ratio (1: 1, 1 :3, and 1:6 Eq. Wt) of alkyd to peracetic acid. The effect of reaction time on the epoxy group content was measured during the epoxidation process. The prepared alkyd resins were analyzed by IR and H1NMR. The metal coated film properties of epoxidized alkyd resins were compared with those of unmodified alkyd resins. It was observed that the coating films of epoxidized alkyd resins have better in drying properties, hardness, adhesion, impact and flexibility than those of un epoxidized alkyd resins. The flammability properties of the paper coated films for the prepared brominated epoxidized alkyd resins were found to be fire retardant

259

Volumetric polymerization shrinkage of contemporary composite resins.  

Science.gov (United States)

The polymerization shrinkage of composite resins may affect negatively the clinical outcome of the restoration. Extensive research has been carried out to develop new formulations of composite resins in order to provide good handling characteristics and some dimensional stability during polymerization. The purpose of this study was to analyze, in vitro, the magnitude of the volumetric polymerization shrinkage of 7 contemporary composite resins (Definite, Suprafill, SureFil, Filtek Z250, Fill Magic, Alert, and Solitaire) to determine whether there are differences among these materials. The tests were conducted with precision of 0.1 mg. The volumetric shrinkage was measured by hydrostatic weighing before and after polymerization and calculated by known mathematical equations. One-way ANOVA (á = 0.05) was used to determine statistically significant differences in volumetric shrinkage among the tested composite resins. Suprafill (1.87+/-0.01) and Definite (1.89+/-0.01) shrank significantly less than the other composite resins. SureFil (2.01+/-0.06), Filtek Z250 (1.99+/-0.03), and Fill Magic (2.02+/-0.02) presented intermediate levels of polymerization shrinkage. Alert and Solitaire presented the highest degree of polymerization shrinkage. Knowing the polymerization shrinkage rates of the commercially available composite resins, the dentist would be able to choose between using composite resins with lower polymerization shrinkage rates or adopting technical or operational procedures to minimize the adverse effects deriving from resin contraction during light-activation. PMID:19089177

Nagem Filho, Halim; Nagem, Haline Drumond; Francisconi, Paulo Afonso Silveira; Franco, Eduardo Batista; Mondelli, Rafael Francisco Lia; Coutinho, Kennedy Queiroz

2007-10-01

260

Adsorption of pesticides on resins.  

Science.gov (United States)

The objective of this work was to assess the capability of organic hydrophobic polymeric resins Amberlite XAD-4 and XAD-7 to remove the pesticides alachlor and amitrole from water. The pesticides adsorption on the two different adsorbents was measured by batch equilibrium technique and isotherm types and parameters were estimated. Two theoretical models were applied based on a Freundlich and a Langmuir isotherms. The effect of pesticides chemical composition and structure as well as the nature of solid surface on the efficiency of adsorption was evaluated. The influence of pH also was studied. In low pH solutions adsorption of amitrole was higher upon the nonionic aliphatic acrylic ester copolymer XAD-7 in comparison to the nonionic, crosslinked macroreticular copolymer of styrene divinylbenzene XAD-4. In neutral and intermediate pH solutions the polar acrylic ester copolymer XAD-7 was more effective to the retention of alachlor. The acrylic ester copolymer showed at pH 3 the lower effectiveness in alachlor removal from water. The data of the adsorption isotherms of pesticides upon the examined polymeric resins seemed to conform to both the Freundlich and the Langmuir isotherm models. PMID:12617554

Kyriakopoulos, Grigorios; Hourdakis, Adamadia; Doulia, Danae

2003-03-01

261

Reduction of polyester resin shrinkage by means of epoxy resin—II. Epoxy resin modified with acrylamide and N-hydroxymethyloloacrylamide  

Science.gov (United States)

The possibility was investigated of reducing the shrinkage of unsaturated polyester resin taking place in radiation-induced curing, by the addition of epoxy resin. In order to combine chemically both resins, the epoxy component was modified by introducing unsaturated bonds via acrylamide and N-hydroxymethyloloacrylamide. A composition of 90% unsaturated polyester resin and 10% acrylamide-modified epoxy resin, filled with silica (1:1.5), showed a volume shrinkage below 2%.

Pietrzak, M.; Brzostowski, A.

262

Embedding of reactor wastes in plastic resins  

International Nuclear Information System (INIS)

STEAG Kernenergie GmbH is so far the only firm commercially to condition radioactive bead ion exchange resins by embedding in polystyrene resins. The objective of the work reported here was to study and develop methods for immobilization of other reactor wastes in plastic resins. Comparison studies on high quality cement however showed favourable results for cement with respect to process safety and economy. For this reason STEAG interrupted its work in the field of resin embedding after about one year. The work carried out during this period is surveyed in this report, which includes a comprehensive literature study on reactor wastes and their solidification in plastic resins as well as on regulations with regard to radioactive waste disposal in the member states of the European Communities

263

Electrodialytic decontamination of spent ion exchange resins  

International Nuclear Information System (INIS)

Development of a novel electrodialytic decontamination process for the selective removal of radioactive Cs from spent ion exchange resins containing large amounts of Li is described. The process involves passage of a dc electric current through a bed of the spent ion exchange resin in a specially designed electrodialytic cell. The radiocesium so removed from a volume of the spent resin is concentrated onto a much smaller volume of a Cs selective sorbent to achieve a significant radioactive waste volume reduction. Technical feasibility of the electrodialytic resin decontamination process has been demonstrated on a bench scale with a batch of simulated spent ion exchange resin and using potassium cobalt ferrocyanide as the Cs selective sorbent. A volume reduction factor between 10 and 17 has been estimated. The process appears to be economically attractive. Improvements in process economics can be expected from optimization of the process. Other possible applications of the EDRD process have been identified

264

Solidification of ion exchange resin wastes  

Energy Technology Data Exchange (ETDEWEB)

Solidification media investigated included portland type I, portland type III and high alumina cements, a proprietary gypsum-based polymer modified cement, and a vinyl ester-styrene thermosetting plastic. Samples formulated with hydraulic cement were analyzed to investigate the effects of resin type, resin loading, waste-to-cement ratio, and water-to-cement ratio. The solidification of cation resin wastes with portland cement was characterized by excessive swelling and cracking of waste forms, both after curing and during immersion testing. Mixed bed resin waste formulations were limited by their cation component. Additives to improve the mechanical properties of portland cement-ion exchange resin waste forms were evaluated. High alumina cement formulations dislayed a resistance to deterioration of mechanical integrity during immersion testing, thus providing a significant advantage over portland cements for the solidification of resin wastes. Properties of cement-ion exchange resin waste forms were examined. An experiment was conducted to study the leachability of /sup 137/Cs, /sup 85/Sr, and /sup 60/Co from resins modified in portland type III and high alumina cements. The cumulative /sup 137/Cs fraction release was at least an order of magnitude greater than that of either /sup 85/Sr or /sup 60/Co. Release rates of /sup 137/Cs in high alumina cement were greater than those in portland III cement by a factor of two.Compressive strength and leach testing were conducted for resin wastes solidified with polymer-modified gypsum based cement. /sup 137/Cs, /sup 85/Sr, and /sup 60/Co fraction releases were about one, two and three orders of magnitude higher, respectively, than in equivalent portland type III cement formulations. As much as 28.6 wt % dry ion exchange resin was successfully solidified using vinyl ester-styrene compared with a maximum of 25 wt % in both portland and gypsum-based cement.

1982-08-01

265

Solidification of ion exchange resin wastes  

International Nuclear Information System (INIS)

Solidification media investigated included portland type I, portland type III and high alumina cements, a proprietary gypsum-based polymer modified cement, and a vinyl ester-styrene thermosetting plastic. Samples formulated with hydraulic cement were analyzed to investigate the effects of resin type, resin loading, waste-to-cement ratio, and water-to-cement ratio. The solidification of cation resin wastes with portland cement was characterized by excessive swelling and cracking of waste forms, both after curing and during immersion testing. Mixed bed resin waste formulations were limited by their cation component. Additives to improve the mechanical properties of portland cement-ion exchange resin waste forms were evaluated. High alumina cement formulations dislayed a resistance to deterioration of mechanical integrity during immersion testing, thus providing a significant advantage over portland cements for the solidification of resin wastes. Properties of cement-ion exchange resin waste forms were examined. An experiment was conducted to study the leachability of 137Cs, 85Sr, and 60Co from resins modified in portland type III and high alumina cements. The cumulative 137Cs fraction release was at least an order of magnitude greater than that of either 85Sr or 60Co. Release rates of 137Cs in high alumina cement were greater than those in portland III cement by a factor of two.Compressive strength and leach testing were conducted for resin wastes solidified with polymer-modified gypsum based cement. 137Cs, 85Sr, and 60Co fraction releases were about one, two and three orders of magnitude higher, respectively, than in equivalent portland type III cement formulations. As much as 28.6 wt % dry ion exchange resin was successfully solidified using vinyl ester-styrene compared with a maximum of 25 wt % in both portland and gypsum-based cement

266

Immobilization of Lactate Oxidase Within a Hybrid Mesoporous Membrane  

Directory of Open Access Journals (Sweden)

Full Text Available The hybrid mesoporous membrane was prepared by using Pluronic F127((PEO106(PRO70(PEO106as a structure-directing agent. Columnar mesoporoussilica was formed inside the anodic aluminium membrane (AAM pores and had a length of ca. (50±2um. Nano-fiber with the diameters of the pores being about 12 nm was aligned along the long axis of the AAM pore walls. The lactate oxidase (LODencapsulation was done by covalent attachment on the inner wall of the silica mesopores. After removing of Pluronic F127 inside the silica mesopores by calcination, the 3-aminopropylethoxysilane (APTMS was immobilized on the inner pore surface. Then, the LOD was covalently attached via a linker of glutaraldehyde(GA and the LOD-M was obtained. The resulting LOD-M was applied for conversion of lactic acid to pyuvic acid. The LOD-M can be used for conversion of lactic acid by using a conventional? ltration apparatus. The proposed scheme allows conversion of lactic acid without separation of the mesoporous silica host from the reaction media. We compared the morphology of the mesoporous material after imobilization of enzyme by TEM and isotherm. The effect on enzyme activity, such as concentration of L-lacate, flow speeds and storage time, was also tested.

HE Jiao

2010-07-01

267

Mesoporous TiO{sub 2}-based PEMFC catalyst supports  

Energy Technology Data Exchange (ETDEWEB)

The interest in ordered mesoporous carbon for use as a fuel cell catalyst support can be attributed to its high surface area, ordered porous structure, and narrow pore size distribution. However, carbon corrosion is one of the factors that influences the durability and reliability of proton exchange membrane fuel cells (PEMFCs). Several strategies have been developed to address this problem and facilitate commercialization of the PEMFC. The strategies include using graphitized carbon, preparing alternative support, and synthesizing transition metal oxide/carbon composite supports. Two types of catalyst supports were investigated in this study, and their properties were then compared. In the first case, ordered mesoporous carbon was coated with titanium oxide (TiO{sub 2}) . A crystalline mesoporous doped-TiO{sub 2} based cermet was prepared in the second case in order to investigate the possibility of decreasing the Pt loading. These materials were characterized by TEM, N2 isotherm, and SEM/EDX analysis. Pt catalysts were deposited on both the mesoporous TiO{sub 2} coated carbon supports and doped-TiO{sub 2} supports. Electrochemical techniques were used to evaluate their catalytic activity and anodic properties. The study also investigated the effect of the TiO{sub 2} coating on the durability of the carbon support and the stability of the mesoporous supports.

Song, C.; Lee, K.; Hui, R.; Zhang, J. [National Research Council of Canada, Vancouver, BC (Canada). Inst. for Fuel Cell Innovation; Chavallier, L.; Jones, D.; Roziere, J. [Montpellier Univ., Montpellier (France). Inst. Charles Gerhardt de Montpellier, Laboratoire des Agregats Interfaces et Materiaux pour l' Energie

2009-07-01

268

Enhancing the Porosity of Mesoporous Carbon-Templated ZSM-5 by Desilication  

DEFF Research Database (Denmark)

A tunable desilication protocol applied on a mesoporous ZSM-5 zeolite synthesized by carbon-templating is reported. The strategy enables a systematic manufacture of zeolite catalysts with moderate to very high mesoporosities. Coupling carbon-templating and desilication thus allow for more than a doubling of the original mesopore volume and mesopore surface area. The porosity effect arising from various treatment times and base amounts in the media has been thoroughly mapped. Initially, small mesopores are created, and as desilication strength increases the average mesopore size enhances. Crystallinity of the treated samples is retained, and electron microscopy indicates solely intracrystalline mesoporosity. (

Holm, Martin Spangsberg; Egeblad, Kresten

2008-01-01

269

Unusual reinforcement of silicone rubber compounds containing mesoporous silica particles as inorganic fillers.  

Science.gov (United States)

We fabricate mesoporous silica/silicone composites in a simple way and systematically examine their thermal stability, swelling characteristic, mechanical strength, and transparency. Simple calculations show that more than 90 vol% of mesopores are filled with silicone rubbers. Compared to non-porous silica/silicone composites, mesoporous silica/silicone composites showed a lower coefficient of linear thermal expansion (CTE). In addition, dramatic improvements of the tensile strength and Young's modulus are obtained with mesoporous silica/silicone composites. Furthermore, mesoporous silica/silicone composites show higher transparency than non-porous silica/silicone composites. PMID:22298187

Suzuki, Norihiro; Kiba, Shosuke; Kamachi, Yuichiro; Miyamoto, Nobuyoshi; Yamauchi, Yusuke

2012-03-14

270

Application of predictive fuzzy logic controller in temperature control of phenol-formaldehyde manufacturing: using MATLAB-SIMULINK methodology  

Science.gov (United States)

In polymer industries, the automation and control of reactors due to the progress in the areas of fuzzy control, neural networks, genetic algorithms, and expert systems lead to more secured and stable operation. When phenol and formaldehyde are mixed together, sudden heat is produced by the nonlinear exothermal reaction. Since sudden heat is liberated, polymerization process requires precise temperature control to avoid temperature run-away and the consequent damage to expensive materials. In practice, human involvement has been a source of errors that affects the quality of the product. This research proposes a design methodology for a sensor based computer control system. The duration of ON and OFF time of the relays is the parameters to be controlled in order to keep the exothermic reaction under control. This paper discusses a detailed simulation study of this exothermal process using MATLAB-SIMULINK-Fuzzy Logic toolbox. The model for the simulation study is derived from the constructed thermal system and responses are obtained. A predictive FLC structure is developed and compared to a classical PID control structure. Simulation results are obtained to ensure that the predictive FLC is better in controlling the reaction temperature.

Yaacob, Sazali; Nagarajan, Ramachandran; Kin, Kenneth T. T.

2001-10-01

271

Synthesis of highly ordered mesoporous Co3O4 for gas sensing.  

Science.gov (United States)

Highly ordered mesoporous Co3O4 nanostructures were prepared using SBA-15 silica as hard templates. The mesoporous structures were characterized by X-ray diffraction, high resolution transmission electron microscopy, and N2 adsorption/desorption isotherm analysis. The results demonstrated that the as-prepared mesoporous Co3O4 has an ordered P6mm symmetric mesoporous structure. The optical absorption properties of the mesoporous Co3O4 were investigatted by UV-Vis spectroscopy and the results indicate that the mesoporous Co3O4 materials are semiconducting with direct band gaps of 2, 1.385 and 0.38 eV. The gas-sensing performance of the mesoporous Co3O4 was tested towards a series of typical solvents. They demonstrated a good sensing performance towards these vapour with rapid response and high sensitivity at low operating temperature. PMID:23858858

Su, D W; Liu, H; Ahn, H J; Wang, G X

2013-05-01

272

Ordered mesoporous materials based on interfacial assembly and engineering.  

Science.gov (United States)

Ordered mesoporous materials have inspired prominent research interest due to their unique properties and functionalities and potential applications in adsorption, separation, catalysis, sensors, drug delivery, energy conversion and storage, and so on. Thanks to continuous efforts over the past two decades, great achievements have been made in the synthesis and structural characterization of mesoporous materials. In this review, we summarize recent progresses in preparing ordered mesoporous materials from the viewpoint of interfacial assembly and engineering. Five interfacial assembly and synthesis are comprehensively highlighted, including liquid-solid interfacial assembly, gas-liquid interfacial assembly, liquid-liquid interfacial assembly, gas-solid interfacial synthesis, and solid-solid interfacial synthesis, basics about their synthesis pathways, princples and interface engineering strategies. PMID:23868196

Li, Wei; Yue, Qin; Deng, Yonghui; Zhao, Dongyuan

2013-10-01

273

Adsorption of vitamin E on mesoporous titania nanocrystals  

Energy Technology Data Exchange (ETDEWEB)

Tri-block nonionic surfactant and titanium chloride were used as starting materials for the synthesis of mesoporous titania nanocrystallite powders. The main objective of the present study was to examine the synthesis of mesoporous titania nanocrystals and the adsorption of vitamin E on those nanocrystals using X-ray diffraction (XRD), transmission electron microscopy, and nitrogen adsorption and desorption isotherms. When the calcination temperature was increased to 300 {sup o}C, the reflection peaks in the XRD pattern indicated the presence of an anatase phase. The crystallinity of the nanocrystallites increased from 80% to 98.6% with increasing calcination temperature from 465 {sup o}C to 500 {sup o}C. The N{sub 2} adsorption data and XRD data taken after vitamin E adsorption revealed that the vitamin E molecules were adsorbed in the mesopores of the titania nanocrystals.

Shih, C.J., E-mail: cjshih@kmu.edu.tw [Department of Fragrance and Cosmetic Science, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Lin, C.T.; Wu, S.M. [School of Pharmacy, College of Pharmacy, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China)

2010-07-15

274

Synthesis and electrochemical capacitance of mesoporous Co(OH)2  

International Nuclear Information System (INIS)

Mesoporous Co(OH)2 was synthesized by using CH3(CH2)10CH2OSO3Na as soft template and urea as hydrolysis-controlling agent. The composition and microstructure of Co(OH)2 was investigated by X-ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM) and nitrogen adsorption and desorption isotherms. Structure characterizations indicated a good mesoporous structure for the prepared Co(OH)2 with adsorption average pore diameter of 11 nm and Brunauer-Emmett-Teller (BET) specific surface area of 283 m2 g-1. Cyclic voltammogram, galvanostatic charge-discharge test, and electrochemical impedance spectroscopy (EIS) analysis showed that the Co(OH)2 possessed good capacitive behavior. The maximum specific capacitance of 341 F g-1 was obtained for the mesoporous Co(OH)2 at a charge/discharge current density of 5 mA cm-2

275

Synthesis of mesoporous silica microsphere from dual surfactant  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english A new procedure is reported to synthesis mesoporous silica micro sphere for the first time. In these method two surfactants namely Span 80 and Tween 80 were used. Small angle X ray diffraction and N2 adsorption analysis shows the synthesized material has mesoporous property. The material has spheric [...] al morphology with 1-10 µm particle size. Beside the material found to have microcapsule property as observed from the Transmission electron microscopy. The Fourier transform Infrared spectroscopic analysis reveals that the materials are similar to other mesoporous materials. We also encapsulated an UV-absorber Ibuprofen inside the microcapsule, by mixing it before the synthesis. This shows a possibility of the materials in cosmetic applications.

Venkatathri, Narayanan.

2008-12-01

276

Synthesis of mesoporous silica microsphere from dual surfactant  

Directory of Open Access Journals (Sweden)

Full Text Available A new procedure is reported to synthesis mesoporous silica micro sphere for the first time. In these method two surfactants namely Span 80 and Tween 80 were used. Small angle X ray diffraction and N2 adsorption analysis shows the synthesized material has mesoporous property. The material has spherical morphology with 1-10 µm particle size. Beside the material found to have microcapsule property as observed from the Transmission electron microscopy. The Fourier transform Infrared spectroscopic analysis reveals that the materials are similar to other mesoporous materials. We also encapsulated an UV-absorber Ibuprofen inside the microcapsule, by mixing it before the synthesis. This shows a possibility of the materials in cosmetic applications.

Venkatathri Narayanan

2008-12-01

277

Polymorphism of the glass former ethanol confined in mesoporous silicon  

CERN Document Server

X-ray diffraction patterns of ethanol confined in parallel-aligned channels of approx. 10 nm diameter and 50 micrometer length in mesoporous silicon have been recorded as a function of filling fraction, temperature and for varying cooling and heating rates. A sorption isotherm, recorded in the liquid state, indicates a three monolayer thick, strongly adsorbed wall layer and a capillary condensed fraction of molecules in the pore center. Though the strongly adsorbed film remains in an amorphous state for the entire temperature range investigated, the capillary condensed molecules reproduce the polymorphism of bulk solid ethanol, that is the formation of either crystalline or glass-like states as a function of cooling rate. The critical rate necessary to achieve a vitrification in the mesopores is, however, at least two orders of magnitude smaller than in the bulk state. This finding can be traced both to pure geometrical constraints and quenched disorder effects, characteristic of confinement in mesoporous sil...

Henschel, Anke; Huber, Patrick; 10.1080/09500831003766999

2010-01-01

278

Treatment of spent ion exchange resin  

International Nuclear Information System (INIS)

Ion exchange resins are generally used for treating radioactive water in atomic power facilities. Such resins are mainly composed of copolymers of styrene and divinylbenzene. In the form of granule or powder, these resins are chemically stable and difficult to treat or disposed of. Investigation and testing have been carried out in an effort to utilize microwaves for volume-reduction treatment of spent ion exchange resins discharged in great amounts from radioactive water processing facilities. An apparatus is developed which can effectively perform heating, combustion and volume reduction of resins. Granules of silicon carbide is used as the material for the moving b-d since it has good microwave-absorbing properties as well as high temperature resistance and thermal conductivity. The granules are mechanically stirred during operation to increase the heating efficiency. A required volume of granular or powdered ion exchange resin is fed after the furnace temperature reaches about 600 ? 700 deg C. This process is found to be very efficient compared to direct application of microwaves to waste resins. Exhaust gas generated in the furnace is processed subsequently in the secondary furnace. The inner wall of the secondary furnace also consists of silicon carbide to promote absorption of microwaves. It has been shown that the furnace temperature can be increased over 100 deg C. It is also found possible to perform quick control of the temperature and combustion process the temperature and combustion process and to carry out combustion of fire resisting waste materials. (Nogami, K.)

279

Approach to CANDU spent resin management  

International Nuclear Information System (INIS)

Among the various approaches to manage spent resins from nuclear power plants, the treatment of CANDU resins by drying, followed by hot super-compaction and packaging provides a waste volume reduction of up to five for long-term storage or final disposal. The additional benefit of carbon-14 removal from some CANDU spent resins during the drying process would allow reclassification of the processed resin to 'Less-than or Equal-to US Class C' low-level radioactive waste. The recovered carbon-14 would be managed as low-volume, 'Greater-than- Class C' waste consisting of metal carbonates stabilized in cement, or could be further volume-reduced in a carbide waste form, if necessary. This paper presents experimental performance data for carbon-14 removal and stabilized waste-forms based on actual and simulated spent-resin samples. The paper also describes the implications of management of the volume-reduced, low-carbon-14 resin waste compared to spent resins stored without drying and compaction. (author)

280

Tc-99 Ion Exchange Resin Testing  

Energy Technology Data Exchange (ETDEWEB)

Pacific Northwest National Laboratory was contracted by CHPRC to evaluate the release of 99Tc from spent resin used to treat water from well 299-W15-765 and stored for several years. The key questions to be answered are: 1) does 99Tc readily release from the spent ion exchange resin after being in storage for several years; 2) if hot water stripping is used to remove the co-contaminant carbon tetrachloride, will 99Tc that has been sequestered by the resin be released; and 3) can spent resin be encapsulated into a cementitious waste form; if so, how much 99Tc would be released from the weathering of the monolith waste form? The results from the long term stability leach test results confirm that the resin is not releasing a significant amount of the sequestered 99Tc, evident by the less than 0.02% of the total 99Tc loaded being identified in the solution. Furthermore, it is possible that the measured 99Tc concentration is the result of 99Tc contained in the pore spaces of the resin. In addition to these results, analyses conducted to examine the impact of hot water on the release of 99Tc suggest that only a small percentage of the total is being released. This suggest that hot water stripping to remove carbon tetrachloride will not have a significant affect on the resin’s ability to hold-on to sequestered 99Tc. Finally, encapsulation of spent resin in a cementitious material may be a viable disposal option, but additional tests are needed to examine the extent of physical degradation caused by moisture loss and the effect this degradation process can have on the release of 99Tc.

Valenta, Michelle M.; Parker, Kent E.; Pierce, Eric M.

2010-08-01

281

Safety evaluation of cation-exchange resins  

International Nuclear Information System (INIS)

Results are presented of a study to evaluate whether sufficient information is available to establish conservative limits for the safe use of cation-exchange resins in separating radionuclides and, if not, to recommend what new data should be acquired. The study was also an attempt to identify in-line analytical techniques for the evaluation of resin degradation during radionuclide processing. The report is based upon a review of the published literature and upon discussions with many people engaged in the use of these resins. It was concluded that the chief hazard in the use of cation-exchange resins for separating radionuclides is a thermal explosion if nitric acid or other strong oxidants are present in the process solution. Thermal explosions can be avoided by limiting process parameters so that the rates of heat and gas generation in the system do not exceed the rates for their transfer to the surroundings. Such parameters include temperature, oxidant concentration, the amounts of possible catalysts, the radiation dose absorbed by the resin and the diameter of the resin column. Current information is not sufficient to define safe upper limits for these parameters. They can be evaluated, however, from equations derived from the Frank-Kamenetskii theory of thermal explosions provided the heat capacities, thermal conductivities and rates of heat evolution in the relevant resin-oxidant mixtures are known. It is recommended that such measurements be made and the appropriate limits be evaluated. A list of additional safety precautions are also presented to aid in the application of these limits and to provide additional margins of safety. In-line evaluation of resin degradation to assess its safety hazard is considered impractical. Rather, it is recommended that the resin be removed from use before it has received the limiting radiation dose, evaluated as described above

282

Mesoporous materials for clean energy technologies.  

Science.gov (United States)

Alternative energy technologies are greatly hindered by significant limitations in materials science. From low activity to poor stability, and from mineral scarcity to high cost, the current materials are not able to cope with the significant challenges of clean energy technologies. However, recent advances in the preparation of nanomaterials, porous solids, and nanostructured solids are providing hope in the race for a better, cleaner energy production. The present contribution critically reviews the development and role of mesoporosity in a wide range of technologies, as this provides for critical improvements in accessibility, the dispersion of the active phase and a higher surface area. Relevant examples of the development of mesoporosity by a wide range of techniques are provided, including the preparation of hierarchical structures with pore systems in different scale ranges. Mesoporosity plays a significant role in catalysis, especially in the most challenging processes where bulky molecules, like those obtained from biomass or highly unreactive species, such as CO2 should be transformed into most valuable products. Furthermore, mesoporous materials also play a significant role as electrodes in fuel and solar cells and in thermoelectric devices, technologies which are benefiting from improved accessibility and a better dispersion of materials with controlled porosity. PMID:24699503

Linares, Noemi; Silvestre-Albero, Ana M; Serrano, Elena; Silvestre-Albero, Joaquín; García-Martínez, Javier

2014-11-21

283

Nanostructured mesoporous carbon as electrodes for supercapacitors  

Energy Technology Data Exchange (ETDEWEB)

Symmetrical carbon/carbon double layer capacitors (EDLCs) were fabricated employing nanostructured mesoporous nongraphitized carbon black (NMCB) powders and their EDLC behavior was studied using electrochemical techniques viz., cyclic voltammetry, a.c.-impedance, and constant current cycling. Rectangular shape cyclic characteristics were observed indicating the double layer behavior of the NMCB carbon electrodes. The mechanism of double layer formation and frequency dependent capacitance were deduced from the ac-impedance analysis. Specific capacitance, power density and energy density were derived from constant current charge/discharge measurements. NMCB powders demonstrated a specific capacitance of about {approx}39Fg{sup -1} and the power density of 782Wkg{sup -1} at a current density of 32mAcm{sup -2}. Nevertheless, at a low current density (3mAcm{sup -2}), the specific capacitance of {approx}44Fg{sup -1} was achieved, which corroborates with the values obtained by means of ac-impedance (40Fg{sup -1}) and cyclic voltammetry (41.5Fg{sup -1}). The test cells demonstrated the stable cycle performance over several hundreds of cycles. (author)

Prabaharan, S.R.S. [School of Electrical and Electronics Engineering, Faculty of Engineering and Computer Science, The University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Vimala, R. [Material Characterization Department, S.E.H. Malaysia Sdn. Bhd Lot 2, Lorong Enggang 35, Ulu Klang Free Trade Zone, 54200 Selangor (Malaysia); Zainal, Zulkarnian [Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Serdang (Malaysia)

2006-10-20

284

Rhodium catalysts bound to functionalized mesoporous silica  

Energy Technology Data Exchange (ETDEWEB)

Phosphine and amine functionalized mesoporous silica materials were metallated with Rh(CO)2(i-Pr2NH)Cl or Rh2(CO)4Cl2, respectively, to yield catalysts containing the Rh(PPh2R)2(CO)Cl or Rh(CO)2(NH2R)Cl, where R is a propyl chain bonded to the silica surface, reactive centers. In order to ascertain the effect of pore size on rates of hydroformylation catalysis both 35 and 45 ? pore size materials were used. Using the hydroformylation of octene as a reference reaction, the phosphine based, 45 ? catalysts were 1.5-1.3 times faster than the amine based, 45 ? materials were 2.6-2.1 times faster than the 35 ? catalysts, and the 45 ? materials. The orientation of the catalyst relative to the functionalized surface, and the steric environment around the catalyst active site appear to be significant in determining rate of reaction. The ability of the surface bound phosphine catalysts to affect hydroformylation was strongly influenced by the steric constraints of the substrate. Terminal alkenes were readily hydroformylated and norbornene was slowly hydroformylated, but pinene, trans-cyclododecene, cyclohexene and cholesterol were nonreactive to the catalytic center.

Bitterwolf, Thomas E.; Newell, J D.; Carver, Colin T.; Addleman, Raymond S.; Linehan, John C.; Fryxell, Glen E.

2004-07-20

285

Luminous Efficient Compositions Based on Epoxy Resin  

Directory of Open Access Journals (Sweden)

Full Text Available Magnesium/sodium nitrate illuminating compositions with epoxy resin - E 605 have beenstudied for luminosity and luminous efficiency by varying fuel oxidizer ratio and binder content.The compositions have been evaluated for impact and friction sensitivities, burn rate, thermalcharacteristics, and mechanical properties. Flame temperature and combustion products areevaluated theoretically by using REAL program. Experimental results show that, luminosity,burn rate, and calorimetric value are higher for polyester resin-based compositions. The highluminous efficiency composition is achieved with magnesium/sodium nitrate ratio of 70/30 with4 per cent epoxy resin.

R.S. Palaiah

2006-07-01

286

Advanced Fibre Reinforced Methyl Nadicimide Resins .  

Directory of Open Access Journals (Sweden)

Full Text Available Glass/carbon/kevlar-reinforced composites were fabricated using two structurally different methl nadicimide resins. The resin content of the laminates was in the range of 32-39 per cent. Interlaminar shear strength (ILSSand flexual strength (FS depended on the structure of the methyl nadicimide resins. A significant decrease in the ILSS was observed on treatment with boiling water for 500 h and on isothermal ageing at 300 degree celsius for 100,250 and 500 h. The limiting oxygen index (LOI was the lowest for laminates based on Kevlar fabrics (i.e.54 whereas the laminates based on glass/carbon showed very high LOI(>90.

Sarfaraz Alam

2013-04-01

287

Studies on cesium uptake by phenolic resins  

International Nuclear Information System (INIS)

The selective removal of cesium by phenolic ion-exchange resins from highly salted alkaline radioactive solutions was studied. The resins were synthesized by alkaline polycondensation of phenol, resorcinol, catechol, and resorcinol-catechol mixture with formaldehyde and characterized for their moisture regain, ion-exchange (H+ ? Na+) capacity, and distribution coefficient (KD) for cesium. The effects of open and sealed curing of the polymers on their properties were studied. The effect of Na+, NaOH, and Cs+ concentration on the uptake of cesium by resorcinol-formaldehyde resin was investigated, in particular. The chemical, thermal, and radiation stabilities of the polymers were also studied

288

Synthesis of Mesoporous Titania with Surfactant and its Characterization  

OpenAIRE

A mesoporous titania was obtained by gelation from Ti-alkoxide in acidic solutions with addition of surfactant cetyltrimetylammonium bromide (CH3(CH2)15N(CH3)3Br) using a sol-gel process. The effects of surfactant concentration on synthesis of mesoporous titania were studied. The structural characterisation was studied by differential thermal analysis, infrared spectroscopy, X-ray diffraction. Studies by X-ray diffraction showed that crystallisation of TiO2 powder occurs at 200°C, above 200?...

Benkacem, T.; Agoudjil, N.

2008-01-01

289

Near-infrared emission from mesoporous crystalline germanium  

Directory of Open Access Journals (Sweden)

Full Text Available Mesoporous crystalline germanium was fabricated by bipolar electrochemical etching of Ge wafer in HF-based electrolyte. It yields uniform mesoporous germanium layers composed of high density of crystallites with an average size 5-7 nm. Subsequent extended chemical etching allows tuning of crystallites size while preserving the same chemical composition. This highly controllable nanostructure exhibits photoluminescence emission above the bulk Ge bandgap, in the near-infrared range (1095-1360nm with strong evidence of quantum confinement within the crystallites.

Abderraouf Boucherif

2014-10-01

290

Pore expansion in mesoporous silicas using supercritical carbon dioxide  

OpenAIRE

In this paper we report the controlled expansion of pores within mesoporous silicas using supercritical carbon dioxide (sc-CO2). Our method uses the tunable density of sc-CO2 to induce the controlled swelling of the triblock copolymer surfactant templating agents, P123 (PEO20PPO69PEO20) and P85 (PEO26PPO39PEO26). This swelling process ultimately leads to the control of pore diameters and hexagonal spacing within the mesoporous silicas. At pressures of approximately 482 bar, pore diameters of ...

Hanrahan, John P.; Copley, Mark P.; Ryan, Kevin M.; Spalding, Trevor R.; Morris, Michael A.; Holmes, Justin D.

2004-01-01

291

Thermally induced Ostwald ripening of mesoporous Ge nanostructures  

Science.gov (United States)

Mesoporous germanium (Ge) is a new nanostructured material with a very high potential for numerous applications. Thermally induced structural evolution of this nanomaterial is a key point for many high-temperature processes, such as epitaxy, for example, in which it can be involved. In this work, we investigate these structural changes occurring during thermal annealing in vacuum in temperature range between 250 and 650 °C. The influences of the annealing temperature and time as well as of the initial porous layer thickness on the morphology reorganization of the mesoporous Ge layer are described in detail. The obtained results are discussed in terms of Lifshitz-Slyozov-Wagner theory.

Tutashkonko, S.; Nychyporuk, T.; Lysenko, V.; Lemiti, M.

2013-01-01

292

Exploring Mass Transfer in Mesoporous Zeolites by NMR Diffusometry  

Directory of Open Access Journals (Sweden)

Full Text Available With the advent of mesoporous zeolites, the exploration of their transport properties has become a task of primary importance for the auspicious application of such materials in separation technology and heterogeneous catalysis. After reviewing the potential of the pulsed field gradient method of NMR (PFG NMR for this purpose in general, in a case study using a specially prepared mesoporous zeolite NaCaA as a host system and propane as a guest molecule, examples of the attainable information are provided.

Ryong Ryoo

2012-04-01

293

Cobalt Ions Improve the Strength of Epoxy Resins  

Science.gov (United States)

Technique developed for improving mechanical strength of epoxy resins by adding cobalt ions in form of tris(acetylacetonato)cobalt (III) complex. Solid cast disks prepared from cobalt ion-containing epoxy resins tested for flexural strength and stiffness. Incorporation of cobalt ions into epoxies increased flexural strength of resins by 10 to 95 percent. Suitable resins for this technique include any liquid or solid TGMDA resins. Improved epoxy formulation proves useful as composite matrix resin, adhesive, or casting resin for applications on commercial and advanced aircraft.

Stoakley, D. M.; St. Clair, A. K.

1986-01-01

294

Method of decomposing radioactive spent ion exchange resins  

International Nuclear Information System (INIS)

Purpose: To improve the decomposability of spent ion exchange resins such as anionic resins, anionic - cationic mixed resins or the likes issued from nuclear power plants. Method: Spent ion exchange resins containing radioactive materials are decomposed by hydrogen peroxide. In this case, anionic exchange resins or mixture of anionic exchange resins and cationic exchange resins are decomposed by using bivalent or trivalent iron ions coexistent with sulfate groups in excess of the amount corresponding to the molar amount of bivalent or trivalent iron ions as a catalyst. Since the anionic exchange resins or the mixture of the anionic exchange resins and cationic resins are decomposed substantially completely, the amount of residue after the decomposition is reduced and the volume-reducing property of the radioactive wastes can be improved to facilitate the solidifying treatment. (Moriyama, K.)

295

The encapsulation of spent ion-exchange resins in an epoxide resin  

International Nuclear Information System (INIS)

Inorganic and organic IX resins have been incorporated into a water-tolerant epoxide resin system. The effect of ?-irradiation to 5 x 109 rads on the mechanical properties of samples containing wet IX resins has been investigated. It was found that although there is a marked embrittlement of the epoxide matrix, useful mechanical properties are retained up to this dose. Gas evolution studies under irradiation and thermogravimetric analyses have also been carried out. (author)

296

Modified BET Equation for Determination of Micropore Pore Volume and Mesopore Surface Area in Microporous-Mesoporous Solids.  

Czech Academy of Sciences Publication Activity Database

Cambridge : Royal Society of Chemistry Publishing, 2009 - (Kaskel, S.; Rodriguez-Reinoso, F.; Seaton, N.), s. 218-224 ISBN 978-1-84755-904-3. ISSN 0260-6291. [International Symposium on the Characterization of Porous Solids /8./. Edinburg (GB), 10.06.2008-13.06.2008] R&D Projects: GA AV ?R IAA4072404; GA AV ?R KAN400720701 Grant ostatní: GA VEGA(SK) 1/3575/06 Institutional research plan: CEZ:AV0Z40720504 Keywords : microporous-mesoporous solids * mesopore surface area * BET equation Subject RIV: CA - Inorganic Chemistry

Šolcová, Olga; Mat?jová, Lenka; Hudec, P.; Schneider, Petr

297

Synthesis of improved phenolic and polyester resins  

Science.gov (United States)

Thirty-seven cured phenolic resin compositions were prepared and tested for their ability to provide improved char residues and moisture resistance over state of the art epoxy resin composite matrices. Cyanate, epoxy novolac and vinyl ester resins were investigated. Char promoter additives were found to increase the anaerobic char yield at 800 C of epoxy novolacs and vinyl esters. Moisture resistant cyanate and vinyl ester compositions were investigated as composite matrices with Thornel 300 graphite fiber. A cyanate composite matrix provided state of the art composite mechanical properties before and after humidity exposure and an anaerobic char yield of 46 percent at 800 C. The outstanding moisture resistance of the matrix was not completely realized in the composite. Vinyl ester resins showed promise as candidates for improved composite matrix systems.

Delano, C. B.

1980-01-01

298

21 CFR 177.1555 - Polyarylate resins.  

Science.gov (United States)

...Components of Single and Repeated Use Food Contact Surfaces § 177.1555 Polyarylate...articles intended for use in contact with food in accordance with the following...resin articles may be used in contact with all foods except beverages...

2010-04-01

299

Photopolymerizable silicone monomers, oligomers, and resins  

International Nuclear Information System (INIS)

The purpose of this chapter is to acquaint the general photopolymer researcher with the historical development of the chemistry and technology of photopolymerizable silicone monomers, fluids, and resins. The current status of research in these areas is assessed. The focus of this chapter is not only on the polymer chemistry and application of this technology, but also on important aspects of the synthetic chemistry involved in the preparation of UV-curable silicone monomers, oligomers, and resins. 236 refs., 6 tabs

300

Damage evolution in a filled epoxy resin  

International Nuclear Information System (INIS)

A method is proposed for studying damage evolution in a filled epoxy resin submitted to low-cycle fatigue loading. Transmission electron microscopy analysis was performed, which indicates a damage mechanism that corresponds well to the decreasing slope of the stress-strain hysteresis observed in strain-controlled fatigue experiments. Also, the suggested damage model appears to be suitable for the simulation of strain-controlled cyclic tests and fits the damage evolution of the filled epoxy resin fairly well

301

Tc-99 Ion Exchange Resin Testing  

International Nuclear Information System (INIS)

Pacific Northwest National Laboratory was contracted by CHPRC to evaluate the release of 99Tc from spent resin used to treat water from well 299-W15-765 and stored for several years. The key questions to be answered are: (1) does 99Tc readily release from the spent ion exchange resin after being in storage for several years; (2) if hot water stripping is used to remove the co-contaminant carbon tetrachloride, will 99Tc that has been sequestered by the resin be released; and (3) can spent resin be encapsulated into a cementitious waste form; if so, how much 99Tc would be released from the weathering of the monolith waste form? The results from the long term stability leach test results confirm that the resin is not releasing a significant amount of the sequestered 99Tc, evident by the less than 0.02% of the total 99Tc loaded being identified in the solution. Furthermore, it is possible that the measured 99Tc concentration is the result of 99Tc contained in the pore spaces of the resin. In addition to these results, analyses conducted to examine the impact of hot water on the release of 99Tc suggest that only a small percentage of the total is being released. This suggest that hot water stripping to remove carbon tetrachloride will not have a significant affect on the resin's ability to hold-on to sequestered 99Tc. Finally, encapsulation of spent resin in a cementitious material may be a viable disposal option, but additional tests are needed to examine the extent of phsts are needed to examine the extent of physical degradation caused by moisture loss and the effect this degradation process can have on the release of 99Tc.

302

Cesium-specific phenolic ion exchange resin  

Science.gov (United States)

A phenolic, cesium-specific, cation exchange resin is prepared by neutralizing resorcinol with potassium hydroxide, condensing/polymerizing the resulting intermediate with formaldehyde, heat-curing the resulting polymer to effect cross-linking and grinding it to desired particle size for use. This resin will selectively and efficiently adsorb cesium ions in the presence of a high concentration of sodium ions with a low carbon to cesium ratio.

Bibler, Jane P. (Aiken, SC); Wallace, Richard M. (Aiken, SC)

1995-01-01

303

Volumetric polymerization shrinkage of contemporary composite resins  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The polymerization shrinkage of composite resins may affect negatively the clinical outcome of the restoration. Extensive research has been carried out to develop new formulations of composite resins in order to provide good handling characteristics and some dimensional stability during polymerizati [...] on. The purpose of this study was to analyze, in vitro, the magnitude of the volumetric polymerization shrinkage of 7 contemporary composite resins (Definite, Suprafill, SureFil, Filtek Z250, Fill Magic, Alert, and Solitaire) to determine whether there are differences among these materials. The tests were conducted with precision of 0.1 mg. The volumetric shrinkage was measured by hydrostatic weighing before and after polymerization and calculated by known mathematical equations. One-way ANOVA (a or = 0.05) was used to determine statistically significant differences in volumetric shrinkage among the tested composite resins. Suprafill (1.87±0.01) and Definite (1.89±0.01) shrank significantly less than the other composite resins. SureFil (2.01±0.06), Filtek Z250 (1.99±0.03), and Fill Magic (2.02±0.02) presented intermediate levels of polymerization shrinkage. Alert and Solitaire presented the highest degree of polymerization shrinkage. Knowing the polymerization shrinkage rates of the commercially available composite resins, the dentist would be able to choose between using composite resins with lower polymerization shrinkage rates or adopting technical or operational procedures to minimize the adverse effects deriving from resin contraction during light-activation.

Halim, Nagem Filho; Haline Drumond, Nagem; Paulo Afonso Silveira, Francisconi; Eduardo Batista, Franco; Rafael Francisco Lia, Mondelli; Kennedy Queiroz, Coutinho.

2007-10-01

304

Synthesis of mesoporous NiO nanoflake array and its enhanced electrochemical performance for supercapacitor application  

International Nuclear Information System (INIS)

Graphical abstract: Self-supported mesoporous NiO nanoflake arrays prepared by a simple hydrothermal synthesis method and show enhanced supercapacitor performance. Display Omitted - Highlights: • Construct self-supported mesoporous NiO nanoflake array. • Mesoporous nanoflake array shows high pseudo-capacitive properties. • Mesoporous nanoflake array structure is favorable for fast ion and electron transfer. - Abstract: Highly porous metal oxide nanoflake arrays are important for developing high-performance electrochemical devices. Herein, mesoporous NiO nanoflake arrays have been successfully prepared by a facile hydrothermal synthesis method. Except for the mesoporous walls, the NiO nanoflakes are interconnected with each other to form macroporous structure. This porous structured NiO nanoflake arrays possess a high specific surface area of ?185 m2 g?1. The supercapacitor performance of the mesoporous NiO nanoflake arrays is fully characterized. The mesoporous NiO nanoflake arrays exhibit weaker polarization, higher specific capacitance and better rate capability than the common NiO nanoflake arrays. The mesoporous NiO nanoflake arrays deliver a specific capacitance of 400 F g?1 at 2 A g?1 and 339 F g?1 at 40 A g?1, respectively, higher than those of the common NiO nanoflake arrays (287 F g?1 at 2 A g?1 and 179 F g?1 at 40 A g?1). The enhanced performance is mainly due to the hierarchical pore system in the mesoporous NiO nanoflake arrays

305

Cleanup of TMI-2 demineralizer resins  

International Nuclear Information System (INIS)

Radiocesium is being removed from Demineralizers A and B (DA and DB by a process that was developed from laboratory tests on small samples of resin from the demineralizers. The process was designed to elute the radiocesium from the demineralizer resins and then to resorb it onto the zeolite ion exchangers contained in the Submerged Demineralizer System (SDS). The process was also required to limit the maximum cesium activities in the resin eluates (SDS feeds) so that the radiation field surrounding the pipelines would not be excessive. The process consists of 17 stages of batch elution. In the initial stage, the resin is contacted with 0.18 M boric acid. Subsequent stages subject the resin to increasing concentrations of sodium in NaH2BO3-H3BO3 solution (total B = 0.35 M) and then 1 M sodium hydroxide in the final stages. Results on the performance of the process in the cleanup of the demineralizers at TMI-2 are compared to those obtained from laboratory tests with small samples of the DA and DB resins. To date, 15 stages of batch elution have been completed on the demineralizers at TMI-2 which resulted in the removal of about 750 Ci of radiocesium from DA and about 3300 Ci from DB

306

Preparation and evaluation of mesoporous cellular foams coating of solid-phase microextraction fibers by determination of tetrabromobisphenol A, tetrabromobisphenol S and related compounds.  

Science.gov (United States)

Two kinds of mesoporous cellular foams (MCFs), including mesoporous silica materials (MCF-1) and phenyl modified mesoporous materials (Ph-MCF-1), were synthesized and for the first time used as fiber-coating materials for solid-phase microextraction (SPME). By using stainless steel wire as the supporting core, four types of fibers were prepared by sol-gel method and immobilized by epoxy-resin method. To evaluate the performance of the home-made fibers for SPME, seven brominated flame retardants (BFRs), including tetrabromobisphenol A (TBBPA), tetrabromobisphenol S (TBBPS) and related compounds were selected as analytes. The main parameters that affect the extraction and desorption efficiencies, such as extraction temperature, extraction time, desorption time, stirring rate and ionic strength of samples were investigated and optimized. The optimized SPME coupled with high performance liquid chromatography (HPLC) was successfully applied to the determination of the seven BFRs in water samples. The linearity range was from 5.0 to 1000 ?g L(-1) for each compound except TBBPS (from 1.0 to 1000 ?g L(-1)), with the correlation coefficients (r(2)) ranging from 0.9993 to 0.9999. The limits of detection of the method were 0.4-0.9 ?g L(-1). The relative standard deviations varied from 1.2 to 5.1% (n=5). The repeatability of fiber-to-fiber and batch-to-batch was 2.5-6.5% and 3.2-6.7%. The recoveries of the BFRs from aqueous samples were in the range between 86.5 and 103.6%. Compared with three commercial fibers (100 ?m PDMS, 85 ?m PA and 65 ?m PDMS/DVB), the MCFs-coated fiber showed about 3.5-fold higher extraction efficiency. PMID:23107130

Wang, Xuemei; Liu, Jiyan; Liu, Aifeng; Liu, Qian; Du, Xinzhen; Jiang, Guibin

2012-11-13

307

Pore ordering in mesoporous matrices induced by different directing agents.  

Czech Academy of Sciences Publication Activity Database

Ro?. 22, ?. 2 (2015), s. 321-331. ISSN 1380-2224 Institutional support: RVO:61388980 Keywords : Mesoporous silica * MCM-41 * Dodecyl-trimethyl ammonium bromide * Hexadecyl-trimethylammonium bromide Subject RIV: CA - Inorganic Chemistry Impact factor: 1.316, year: 2013

Putz, A.-M.; Cecilia, S.; Ianasi, C.; Dudás, Z.; Székely, N. K.; Plocek, Ji?í; Sfarloaga, P.; Sacarescu, L.; Almásy, L.

2015-01-01

308

Mesoporous molecular sieves as advanced supports for olefin metathesis catalysts.  

Czech Academy of Sciences Publication Activity Database

Ro?. 257, 21-22 (2013), s. 3107-3124. ISSN 0010-8545 R&D Projects: GA AV ?R IAA400400805; GA ?R GBP106/12/G015 Institutional support: RVO:61388955 Keywords : Olefin metathesis * mesoporous molecular sieves * Heterogeneous catalysts Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 12.098, year: 2013

Balcar, Hynek; ?ejka, Ji?í

2013-01-01

309

Thermal conductivity of a kind of mesoporous silica SBA-15  

International Nuclear Information System (INIS)

Mesoporous silica SBA-15 consists of uniform hexagonal, unconnected cylindrical channels with diameters that can be tuned within a range of 1.5 nm–30 nm, and is thought to have a special thermal conductivity. The theoretical investigation of the shell thermal conductivity of the mesoporous silica is performed in the relaxation time approximation in this paper and an available one-dimensional heat transfer model is used to predict the effective thermal conductivity (ETC) of the mesoporous silica. The experimental result of the ETC is also presented for comparison. The shell thermal conductivity of the mesoporous silica decreases with mesochannel radius increasing or wall thickness decreasing, but does not strictly decrease with porosity increasing. The thermal radiation possibly plays a primary role in heat transfer at the large porosity scale. The predicted ETC of SBA-15 with only conduction considered is quite low at the large porosity, even lower than the thermal conductivity of the silica aerogels. To realize it, doping carbon or other matters which can strongly absorb infrared light into SBA-15 is a possible way

310

Correct Determination of Textural Properties in Microporous-Mesoporous Solids.  

Czech Academy of Sciences Publication Activity Database

2010, s. 26. ISBN N. [International Conference on Pure and Applied Chemistry (ICPAC-2010). Mauritius (MU), 26.07.2010-30.07.2010] R&D Projects: GA AV ?R KAN400720701; GA ?R GA104/09/0694 Institutional research plan: CEZ:AV0Z40720504 Keywords : texture * micro-mesoporous solids * physisorption Subject RIV: CF - Physical ; Theoretical Chemistry

Šolcová, Olga; Šnajdaufová, Hana; Mat?jová, Lenka

311

Mesoporous W??O?? hollow spheres as highly active photocatalysts.  

Science.gov (United States)

Mesoporous hollow W18O49 spheres were fabricated by a facile solvent-induced assembly method using anhydrous WCl6 as a precursor and CH3COOH as a solvent. This unique structure exhibited remarkably enhanced photocatalytic and photoelectrocatalytic performance than other morphologies like urchin and nanowire due to the simultaneous enhancement in light harvesting, surface area and adsorption capability. PMID:24995560

Huang, Zhen-Feng; Song, Jiajia; Pan, Lun; Lv, Fenglei; Wang, Qingfa; Zou, Ji-Jun; Zhang, Xiangwen; Wang, Li

2014-09-28

312

Tailored Mesoporous Silicas: From Confinement Effects to Catalysis  

Energy Technology Data Exchange (ETDEWEB)

Ordered mesoporous silicas continue to find widespread use as supports for diverse applications such as catalysis, separations, and sensors. They provide a versatile platform for these studies because of their high surface area and the ability to control pore size, topology, and surface properties over wide ranges. Furthermore, there is a diverse array of synthetic methodologies for tailoring the pore surface with organic, organometallic, and inorganic functional groups. In this paper, we will discuss two examples of tailored mesoporous silicas and the resultant impact on chemical reactivity. First, we explore the impact of pore confinement on the thermochemical reactivity of phenethyl phenyl ether (PhCH2CH2OPh, PPE), which is a model of the dominant {beta}-aryl ether linkage present in lignin derived from woody biomass. The influence of PPE surface immobilization, grafting density, silica pore diameter, and presence of a second surface-grafted inert 'spacer' molecule on the product selectivity has been examined. We will show that the product selectivity can be substantially altered compared with the inherent gas-phase selectivity. Second, we have recently initiated an investigation of mesoporous silica supported, heterobimetallic oxide materials for photocatalytic conversion of carbon dioxide. Through surface organometallic chemistry, isolated M-O-M species can be generated on mesoporous silicas that, upon irradiation, form metal to metal charge transfer bands capable of converting CO{sub 2} into CO. Initial results from studies of Ti(IV)-O-Sn(II) on SBA-15 will be presented.

Buchanan III, A C [ORNL; Kidder, Michelle [ORNL

2010-01-01

313

Mesoporous Molecular Sieves as Advanced Supports for Olefin Metathesis Catalysts.  

Czech Academy of Sciences Publication Activity Database

Ro?. 293, ?. 1 (2010), s. 43-47. ISSN 1022-1360 R&D Projects: GA AV ?R IAA400400805; GA AV ?R KAN100400701 Institutional research plan: CEZ:AV0Z40400503 Keywords : heterogeneous catalysts * mesoporous molecular sieves * olefin metathesis Subject RIV: CF - Physical ; Theoretical Chemistry

Balcar, Hynek; ?ejka, Ji?í

2010-01-01

314

Contamination-resistant silica antireflective coating with closed ordered mesopores.  

Science.gov (United States)

Porous silica optical antireflective (AR) coatings prepared by traditional sol-gel method have been extensively used for high power laser systems, but a serious drawback is that contamination existing in the high vacuum is easily absorbed by the disordered open pore structure, resulting in a fast decrease in transmittance. To improve the stability of transmittance in vacuum, a contamination-resistant silica AR coating with ordered mesopores completely closed by hydrophobic-oleophobic groups was successfully developed on a fused quartz substrate. The ordered mesopores in the coating were controlled under the direction of surfactant F127 via an evaporation-induced-self-assembling process and then were closed by post-grafting long chain fluoroalkylsilane. The grazing incidence small angle X-ray scattering (GISAXS) and the X-ray reflectivity (XRR) results indicated that the mesopores in the coating constructed a Fmmm orthorhombic symmetry structure with a (010) plane parallel to the substrate. Cage-like mesopores were confirmed by nitrogen adsorption-desorption analysis. The obtained coatings showed low surface roughness, excellent abrase-resistance and high transmittance of 100% on quartz substrate. Especially, the decrease of transmittance tested with polydimethylsiloxane pollution in vacuum within one-month was as small as 0.02%. The laser induced damage threshold was up to 59.8 J cm(-2) at a 12 ns laser pulse of 1053 nm wavelength. This work provides an alternative way to fabricate AR coatings with high stability. PMID:25000419

Sun, Jinghua; Zhang, Qinghua; Ding, Ruimin; Lv, Haibing; Yan, Hongwei; Yuan, Xiaodong; Xu, Yao

2014-08-21

315

Mesoporous molecular sieves as supports for metathesis catalysts.  

Czech Academy of Sciences Publication Activity Database

Dordrecht : Springer, 2007, s. 151-166. ISBN 978-1-4020-6090-8 R&D Projects: GA AV ?R IAA4040411; GA ?R GA203/05/2194 Institutional research plan: CEZ:AV0Z40400503 Keywords : mesoporous molecular sieves * heterogeneous catalysts * olefin metathesis * metathesis polymerization Subject RIV: CF - Physical ; Theoretical Chemistry

Balcar, Hynek; ?ejka, Ji?í

316

Core/shell magnetic mesoporous silica nanoparticles with radially oriented wide mesopores  

Directory of Open Access Journals (Sweden)

Full Text Available Core/shell nanoparticles, containing magnetic iron-oxide (maghemite core and mesoporous shell with radial porous structure, were prepared by dispersing magnetite nanoparticles and adding tetraethylorthosilicate to a basic aqueous solution containing structure-templating cetyltrimethylammonium bromide and a pore-swelling mesithylene. The material is characterized by SEM and TEM imaging, nitrogen sorption and powder X-ray di?raction. Distinctive features of the prepared material are its high surface area (959 m2/g, wide average pore diameter (12.4 nm and large pore volume (2.3 cm3/g. The material exhibits radial pore structure and the high angle XRD pattern characteristic for maghemite nanoparticles, which are obtained upon calcination of the magnetite-containing material. The observed properties of the prepared material may render the material applicable in separation, drug delivery, sensing and heterogeneous catalysis.

Nikola Ž. Kneževi?

2014-06-01

317

Imide modified epoxy matrix resins  

Science.gov (United States)

The results of a program designed to develop tough imide modified epoxy resins cured by bisimide amine (BIA) hardeners are described. State-of-the-art epoxides MY720 and DER383 were used, and four bismide amines were evaluated. These were the BIA's derived from the 6F anhydride (4,4'-(hexafluoroisopropylidene) bis(phthalic anhydride) and the diamines 3,3'-diaminodiphynyl sulfone, 4,4'-oxygianiline, 4,4'-methylene dianiline, and 1,12-dodecane diamine. A key intermediate, designated 6F anhydride, is required for the synthesis of the bisimide amines. Reaction parameters to synthesize a precursor to the 6F anhydride (6FHC) in high yields were investigated. The catalyst trifluoromethane sulfonic acid was studied. Although small scale runs yielded the 6FHC in 50 percent yield, efforts to ranslate these results to a larger scale synthesis gave the 6FHC in only 9 percent yield. Results show that the concept of using bisimide amine as curing agents to improve the toughness properties of epoxies is valid.

Scola, D. A.

1984-01-01

318

Mesoporous-silica films, fibers, and powders by evaporation  

Science.gov (United States)

This invention pertains to surfactant-templated nanometer-scale porosity of a silica precursor solution and forming a mesoporous material by first forming the silica precursor solution into a preform having a high surface area to volume ratio, then rapid drying or evaporating a solvent from the silica precursor solution. The mesoporous material may be in any geometric form, but is preferably in the form of a film, fiber, powder or combinations thereof. The rapid drying or evaporation of solvent from the solution is accomplished by layer thinning, for example spin casting, liquid drawing, and liquid spraying respectively. Production of a film is by layer thinning, wherein a layer of the silica precursor solution is formed on a surface followed by removal of an amount of the silica precursor solution and leaving a geometrically thinner layer of the silica precursor solution from which the solvent quickly escapes via evaporation. Layer thinning may be by any method including but not limited to squeegeeing and/or spin casting. In powder formation by spray drying, the same conditions of fast drying exists as in spin-casting (as well as in fiber spinning) because of the high surface-area to volume ratio of the product. When a powder is produced by liquid spraying, the particles or micro-bubbles within the powder are hollow spheres with walls composed of mesoporous silica. Mesoporous fiber formation starts with a similar silica precursor solution but with an added pre-polymer making a pituitous mixture that is drawn into a thin strand from which solvent is evaporated leaving the mesoporous fiber(s).

Bruinsma, Paul J. (San Diego, CA); Baskaran, Suresh (Kennewick, WA); Bontha, Jagannadha R. (Richland, WA); Liu, Jun (Richland, WA)

2008-05-06

319

Textural manipulation of mesoporous materials for hosting of metallic nanocatalysts.  

Science.gov (United States)

The preparation and stabilization of nanoparticles are becoming very crucial issues in the field of so-called "nanocatalysis". Recent developments in supramolecular self-assembled porous materials have opened a new way to get nanoparticles hosted in the channels of such materials. In this paper, a new approach towards monodisperse and thermally stable metal nanoparticles by confining them in ordered mesoporous materials is presented, and three aspects are illustrated. Firstly, the recent progress in the functional control of mesoporous materials will be briefly introduced, and the rational tuning of the textures, pore size, and pore length is demonstrated by controlling supramolecular self-assembly behavior. A novel synthesis of short-pore mesoporous materials is emphasized for their easy mass transfer in both biomolecule absorption and the facile assembly of metal nanocomposites within their pore channels. In the second part, the different routes for encapsulating monodisperse nanoparticles inside channels of porous materials are discussed, which mainly includes the ion-exchange/conventional incipient wetness impregnation, in situ encapsulation routes, organometallic methodologies, and surface functionalization schemes. A facile in situ autoreduction route is highlighted to get monodisperse metal nanoparticles with tunable sizes inside the channels of mesoporous silica. Finally, confinement of mesoporous materials is demonstrated to improve the thermal stability of monodisperse metal nanoparticles catalysts and a special emphasis will be focused on the stabilization of the metal nanoparticles with a low Tammann temperature. Several catalytic reactions concerning the catalysis of nanoparticles will be presented. These uniform nanochannels, which confine monodisperse and stable metal nanoparticles catalysts, are of great importance in the exploration of size-dependent catalytic chemistry and further understanding the nature of catalytic reactions. PMID:18668502

Sun, Junming; Bao, Xinhe

2008-01-01

320

Near-field radiative heat transfer in mesoporous alumina  

Science.gov (United States)

The thermal conductivity of mesoporous material has aroused the great interest of scholars due to its wide applications such as insulation, catalyst, etc. Mesoporous alumina substrate consists of uniformly distributed, unconnected cylindrical pores. Near-field radiative heat transfer cannot be ignored, when the diameters of the pores are less than the characteristic wavelength of thermal radiation. In this paper, near-field radiation across a cylindrical pore is simulated by employing the fluctuation dissipation theorem and Green function. Such factors as the diameter of the pore, and the temperature of the material are further analyzed. The research results show that the radiative heat transfer on a mesoscale is 2˜4 orders higher than on a macroscale. The heat flux and equivalent thermal conductivity of radiation across a cylindrical pore decrease exponentially with pore diameter increasing, while increase with temperature increasing. The calculated equivalent thermal conductivity of radiation is further developed to modify the thermal conductivity of the mesoporous alumina. The combined thermal conductivity of the mesoporous alumina is obtained by using porosity weighted dilute medium and compared with the measurement. The combined thermal conductivity of mesoporous silica decreases gradually with pore diameter increasing, while increases smoothly with temperature increasing, which is in good agreement with the experimental data. The larger the porosity, the more significant the near-field effect is, which cannot be ignored. Project supported by the National Natural Science Foundation of China (Grant No. 51422601), the National Basic Research Program of China (Grant No. 2012CB720404), and the National Key Technology Research and Development Program of China (Grant No. 2013BAJ01B03).

Jing, Li; Yan-Hui, Feng; Xin-Xin, Zhang; Cong-Liang, Huang; Ge, Wang

2015-01-01

321

Magnetic mesoporous materials for removal of environmental wastes  

Energy Technology Data Exchange (ETDEWEB)

We have synthesized two different magnetic mesoporous materials that can be easily separated from aqueous solutions by applying a magnetic field. Synthesized magnetic mesoporous materials, Mag-SBA-15 (magnetic ordered mesoporous silica) and Mag-OMC (magnetic ordered mesoporous carbon), have a high loading capacity of contaminants due to high surface area of the supports and high magnetic activity due to the embedded iron oxide particles. Application of surface-modified Mag-SBA-15 was investigated for the collection of mercury from water. The mercury adsorption using Mag-SBA-15 was rapid during the initial contact time and reached a steady-state condition, with an uptake of approximately 97% after 7 hours. Application of Mag-OMC for collection of organics from water, using fluorescein as an easily trackable model analyte, was explored. The fluorescein was absorbed into Mag-OMC within minutes and the fluorescent intensity of solution was completely disappeared after an hour. In another application, Mag-SBA-15 was used as a host of tyrosinase, and employed as recyclable catalytic scaffolds for tyrosinase-catalyzed biodegradation of catechol. Tyrosinase aggregates in Mag-SBA-15, prepared in a two step process of tyrosinase adsorption and crosslinking, could be used repeatedly for catechol degradation with no serious loss of enzyme activity. Considering these results of cleaning up water from toxic inorganic, organic and biochemical contaminants, magnetic mesoporous materials have a great potential to be employed for the removal of environmental contaminants and potentially for the application in large-scale wastewater treatment plants.

Kim, Byoung Chan; Lee, Jinwoo; Um, Wooyong; Kim, Jaeyun; Joo, Jin; Lee, Jin Hyung; Kwak, Ja Hun; Kim, Jae Hyun; Lee, Changha; Lee, Hongshin; Addleman, Raymond S.; Hyeon, Taeghwan; Gu, Man Bock; Kim, Jungbae

2011-09-15

322

Tooth brush abrasion of paint-on resins for shade modification of crown and bridge resins.  

Science.gov (United States)

The purpose of this study was to evaluate the surface roughness and resistance to toothbrush abrasion of three experimental paint-on composite resins developed for the shade modification of crown and bridge resins. The paint-on resins had less filler volume fraction than restorative composites or the crown and bridge resins and consequently were of low viscosity. The maximum surface roughness (Rmax) and the maximum depth loss by abrasion for the paint-on resins following 40,000 cycles of brushing ranged from 2.45 to 4.07 microm and 8.63 to 13.67 microm, respectively. Rmax values were 37.7-67.5% lower than that for the crown and bridge resin subjected to the same test. Wear depth was 19.9-49.4% lower than for the crown and bridge resin. These results suggest that the paint-on resins are expected to have adequate resistance to toothbrush abrasion and may therefore be suitable for clinical use. PMID:14620991

Fujii, Koichi; Ban, Seiji; McCabe, John F

2003-09-01

323

USE OF BABAÇU FLOUR WITH ALTERNATIVE EXTENDER FOR PLYWOOD MANUFACTURING  

Directory of Open Access Journals (Sweden)

Full Text Available This work aims at evaluating the potentiality of babaçu flour under differents percents (0%, 50%, 75%, and 100% as alternative extensers to wheatmeal for plywood manufacturing. Third three panels with five veneers were produced using Araucaria angustifolia (Bert. Ktze, with urea-formaldehyde – UF and phenol-formaldehyde – FF resins and being three panels per treatment. The following formulations (in parts per wheight were used: UF resin – 100 x extender – 50 x water – 50 x catalyst – 7 and FF resin – 100 x extender – 18 x water – 22. The results of both glue line shear strength obtained for plywood manufactured with urea-formaldehyde and phenol-formaldehyde resins showed the feasibility of the use of babaçu flour as the extender in parcial or total substitution of wheat flour in the plywood manufactures.

Érika da Silva Ferreira

2009-10-01

324

Synthesis, characterization and catalytic activity of a novel mesoporous ZSM-5 zeolite  

Energy Technology Data Exchange (ETDEWEB)

Highlights: ? Mesoporous ZSM-5 zeolites. ? The strong acidic intensity. ? High activity for the alkylation of phenol and tert-butyl alcohol. ? Remarkable hydrothermal stability. - Abstract: A novel mesoporous ZSM-5 zeolite was hydrothermally synthesized using glucose as a template. Characterizations by XRD, TEM and nitrogen isotherms indicated that ZSM-5 possessed worm-like mesoporous. {sup 27}Al-MAS-NMR and NH{sub 3}-TPD showed that the mesoporous ZSM-5 preserved tetrahedral coordination aluminum and stronger acidity than conventional mesoporous material. As-prepared mesoporous ZSM-5 was successfully used in alkylation reaction of phenol with tert-butanol and exhibited significantly high phenol conversion and 2,4-DTBP selectivity. In addition, the hydrothermal stability was also studied by boiling in water for 7 days and displayed good results.

Ma, Yuanyuan [College of Chemistry, Jilin University, Changchun 130023 (China); Key Laboratory of Fine Chemicals of College of Heilongjiang Province, Qiqihar University, Qiqihar 161006 (China); Hu, Jing [College of Chemistry, Jilin University, Changchun 130023 (China); Jia, Lihua [Key Laboratory of Fine Chemicals of College of Heilongjiang Province, Qiqihar University, Qiqihar 161006 (China); Li, Zhifang [College of Chemistry, Jilin University, Changchun 130023 (China); Kan, Qiubin, E-mail: catalysischina@yahoo.com.cn [College of Chemistry, Jilin University, Changchun 130023 (China); Wu, Shujie, E-mail: wusj@jlu.edu.cn [College of Chemistry, Jilin University, Changchun 130023 (China)

2013-05-15

325

Pretreatment Effect on CO Oxidation over Highly Ordered Mesoporous Silver Catalyst  

International Nuclear Information System (INIS)

Highly ordered mesoporous silver material was successfully synthesized from a mesoporous silica template (KIT-6) with 3-D channel structure using the nano-replication method. The effects of H2 or O2 pretreatments on the catalytic performance of the mesoporous silver were investigated using a temperature programmed CO oxidation technique in a fixed bed reactor. The mesoporous silver material that was pretreated with H2 exhibited an excellent catalytic activity compared to the as-prepared and O2-pretreated catalysts. Moreover, this present mesoporous silver material showed good catalytic stability. For the CO oxidation, the apparent activation energy of the H2-pretreated mesoporous silver catalyst was 61 ± 0.5 kJ mol-1, which was also much lower than the as-prepared (132 ± 1.5 kJ mol-1) and O2-pretreated (124 ± 1.4 kJ mol-1) catalysts

326

Synthesis of mesoporous Beta and Sn-Beta zeolites and their catalytic performances.  

Science.gov (United States)

Mesoporous Beta zeolite has been successfully prepared through hydrothermal synthesis in the presence of cationic ammonium-modified chitosan as the meso-template. Through a subsequent solid-gas reaction between highly dealuminated mesoporous Beta zeolite and SnCl4 steam at an elevated temperature, mesoporous Sn-Beta has been facilely obtained. It was revealed that the addition of cationic chitosan induced the nanocrystal aggregation to particle sizes of ?300 nm, giving rise to the intercrystalline/interparticle mesoporosity. In the Sn-implanting procedure, Sn species were demonstrated to be doped into the framework of the resulting mesoporous Beta zeolite in a tetrahedral environment without structural collapse. Due to the micro/mesoporous structures, both mesoporous Beta and Sn-Beta exhibited superior performances in ?-pinene isomerization, Baeyer-Villiger oxidation of 2-adamantanone by hydrogen peroxide and the isomerization of glucose in water, respectively. PMID:24777171

Jin, Junjiang; Ye, Xinxin; Li, Yongsheng; Wang, Yanqin; Li, Liang; Gu, Jinlou; Zhao, Wenru; Shi, Jianlin

2014-06-14

327

Thermal cycling effects on adhesion of resin-bovine enamel junction among different composite resins.  

Science.gov (United States)

Thermal cycling is used to mimic the changes in oral cavity temperature experienced by composite resins when used clinically. The purpose of this study is to assess the thermal cycling effects of in-house produced composite resin on bonding strength. The dicalcium phosphate anhydrous filler surfaces are modified using nanocrystals and silanization (w/NP/Si). The resin is compared with commercially available composite resins Filtek Z250, Z350, and glass ionomer restorative material GIC Fuji-II LC (control). Different composite resins were filled into the dental enamel of bovine teeth. The bond force and resin-enamel junction graphical structures of the samples were determined after thermal cycling between 5 and 55°C in deionized water for 600 cycles. After thermal cycling, the w/NP/Si 30wt%, 50wt% and Filtek Z250, Z350 groups showed higher shear forces than glass ionomer GIC, and w/NP/Si 50wt% had the highest shear force. Through SEM observations, more of the fillings with w/NP/Si 30wt% and w/NP/Si 50wt% groups flowed into the enamel tubule, forming closed tubules with the composite resins. The push-out force is proportional to the resin flow depth and uniformity. The push-out tubule pore and resin shear pattern is the most uniform and consistent in the w/NP/Si 50wt% group. Accordingly, this developed composite resin maintains great mechanical properties after thermal cycling. Thus, it has the potential to be used in a clinical setting when restoring non-carious cervical lesions. PMID:25047352

Chen, Wen-Cheng; Ko, Chia-Ling; Wu, Hui-Yu; Lai, Pei-Ling; Shih, Chi-Jen

2014-10-01

328

Hot dewatering and resin encapsulation of intermediate level radioactive waste  

International Nuclear Information System (INIS)

The chemistry of the processes involved in the hot dewatering and encapsulation of alumino-ferric hydroxide floc in epoxide resin have been studied. Pretreatment of the floc to reduce resin attack and hydrolysis and to increase the dimensional stability of the solidified wasteform has been evaluated. It has been demonstrated that removal of ammonium nitrate from the floc and control of the residual water in the resin are important factors in ensuring dimensional stability of the solidified resin. Resin systems have been identified which, together with the appropriate waste pretreatment have successfully encapsulated a simulated magnox sludge producing a stable wasteform having mechanical and physical properties comparable with the basic resin. (author)

329

Discussion on spent fuel bay purification resin selection  

International Nuclear Information System (INIS)

The performance of spent fuel bay (SFB) clean up system is important for both radiation and radwaste reduction. Demineralizer resin is operated adverse conditions facing high levels of hydrogen peroxide generated from radiolysis of water and also direct radiation attack from radioactive colloids in the pool. Resin cross-linked structure will be easily destroyed, because of sulfate ion and purification efficiency rise and decline. This paper, through nuclear resin oxidation stability tests and based on the nuclear power plant application experience, discusses the failure mechanism of resin, and give the purification resin selection principle, in order to improve the purification efficiency and reduce the amount of radioactive spent resin. (authors)

330

Fabrication of mesoporous metal chalcogenide nanoflake silica thin films and spongy mesoporous CdS and CdSe.  

Science.gov (United States)

Mesoporous silica metal oxide (ZnO and CdO) thin films have been used as metal ion precursors to produce the first examples of mesoporous silica metal sulfide (meso-SiO(2) @ZnS, meso-SiO(2) @CdS) or silica metal selenide (meso-SiO(2) @ZnSe, meso-SiO(2) @CdSe) thin films, in which the pore walls are made up of silica and metal sulfide or metal selenide nanoflakes, respectively. A gentle chemical etching with a dilute HF solution of the meso-SiO(2) @CdS (or meso-SiO(2) @CdSe) produces mesoporous cadmium sulfide (meso-CdS) (or cadmium selenide, meso-CdSe). Surface modified meso-CdS displays bright blue photoluminescence upon excitation with a UV light. The mesoporous silica metal oxides are formed as metal oxide nanoislands over the silica walls through a self-assembly process of a mixture of metal nitrate salt-two surfactants-silica source followed by calcination step. The reactions, between the H(2) S (or H(2) Se) gas and solid precursors, have been carried out at room temperature and monitored using spectroscopy and microscopy techniques. It has been found that these reactions are: 1)?taking place through the diffusion of sulfur or selenium species from the top metal oxide layer to the silica metal oxide interface and 2)?slow and can be stopped at any stage to obtain mesoporous silica metal oxide metal sulfide or silica metal oxide metal selenide intermediate thin films. PMID:22344939

Türker, Yurdanur; Karakaya, Cüneyt; Dag, Ömer

2012-03-19

331

A Sweet Killer: Mesoporous Polysaccharide Confined Silver Nanoparticles for Antibacterial Applications  

OpenAIRE

Silver nanoparticles (AgNP) confined within porous starch have been prepared in a simple, green and efficient manner, utilising the nanoporous structure of predominantly mesoporous starch (MS) to act as nanoparticle stabiliser, support and reducing surface. MS/AgNP materials present high surface areas (SBET > 150 m2 g?1) and mesopore volumes (Vmeso > 0.45 cm3 g?1). The interaction of the AgNP precursor and forming nanoparticle nuclei with the mesoporous domains of the porous polysac...

Moir, James W. B.; Clark, James H.; White, Robin J.; Budarin, Vitaly L.

2011-01-01

332

CuO nanoparticles encapsulated inside Al-MCM-41 mesoporous materials via direct synthetic route  

OpenAIRE

Highly ordered aluminum-containing mesoporous silica (Al-MCM-41) was prepared using attapulgite clay mineral as a Si and Al source. Mesoporous complexes embedded with CuO nanoparticles were subsequently prepared using various copper sources and different copper loadings in a direct synthetic route. The resulting CuO/Al-MCM-41 composite possessed p6mm hexagonally symmetry, well-developed mesoporosity, and relatively high BET surface area. In comparison to pure silica, these mesoporous material...

Chengli Huo; Jing Ouyang; Huaming Yang

2014-01-01

333

Highly mesoporous metal–organic framework assembled in a switchable solvent  

OpenAIRE

The mesoporous metal–organic frameworks are a family of materials that have pore sizes ranging from 2 to 50?nm, which have shown promising applications in catalysis, adsorption, chemical sensing and so on. The preparation of mesoporous metal–organic frameworks usually needs the supramolecular or cooperative template strategy. Here we report the template-free assembly of mesoporous metal–organic frameworks by using CO2-expanded liquids as switchable solvents. The mesocellular metal–o...

Peng, Li; Zhang, Jianling; Xue, Zhimin; Han, Buxing; Sang, Xinxin; Liu, Chengcheng; Yang, Guanying

2014-01-01

334

Synthesis of Ordered Mesoporous Phenanthrenequinone-Carbon via ?-? Interaction-Dependent Vapor Pressure for Rechargeable Batteries  

Science.gov (United States)

The ?-? interaction-dependent vapour pressure of phenanthrenequinone can be used to synthesize a phenanthrenequinone-confined ordered mesoporous carbon. Intimate contact between the insulating phenanthrenequinone and the conductive carbon framework improves the electrical conductivity. This enables a more complete redox reaction take place. The confinement of the phenanthrenequinone in the mesoporous carbon mitigates the diffusion of the dissolved phenanthrenequinone out of the mesoporous carbon, and improves cycling performance.

Kwon, Mi-Sook; Choi, Aram; Park, Yuwon; Cheon, Jae Yeong; Kang, Hyojin; Jo, Yong Nam; Kim, Young-Jun; Hong, Sung You; Joo, Sang Hoon; Yang, Changduk; Lee, Kyu Tae

2014-12-01

335

Synthesis of Ordered Mesoporous Phenanthrenequinone-Carbon via ?-? Interaction-Dependent Vapor Pressure for Rechargeable Batteries  

OpenAIRE

The ?-? interaction-dependent vapour pressure of phenanthrenequinone can be used to synthesize a phenanthrenequinone-confined ordered mesoporous carbon. Intimate contact between the insulating phenanthrenequinone and the conductive carbon framework improves the electrical conductivity. This enables a more complete redox reaction take place. The confinement of the phenanthrenequinone in the mesoporous carbon mitigates the diffusion of the dissolved phenanthrenequinone out of the mesoporous c...

Kwon, Mi-sook; Choi, Aram; Park, Yuwon; Cheon, Jae Yeong; Kang, Hyojin; Jo, Yong Nam; Kim, Young-jun; Hong, Sung You; Joo, Sang Hoon; Yang, Changduk; Lee, Kyu Tae

2014-01-01

336

Method of decomposing ion exchange resin wastes  

International Nuclear Information System (INIS)

Purpose: To attain the shortening for the processing time, economization for the amount of chemical consumed and reduction in the size of the device upon decomposing treatment of radioactive ion exchange resins wastes by using oxidizers. Method: A reaction vessel for conducting pulverization and conversion into inorganic substances as the decomposing step for resin wastes is made of corrosion resistant and non-magnetic material and a great amount of spindle-like actuation pieces made of ferromagnetic material are contained in the vessel. Resin wastes and oxidizers (hydrogen peroxide), and decomposing catalyst (iron ions) are supplied to the vessel. When electric power is supplied to a moving type magnetic field generator disposed on both sides of the vessel, moving magnetic fields act to the inside of the vessel thereby causing each of the actuation pieces to float upwardly, rotate around its axis and revolve around the vessel. Thus, the resin wastes are pulverized into almost colloidal state, mixed sufficiently and reacted with chemicals and decomposed into inorganic materials. According to the result of the experiment, about 100 % of the resin wastes can be converted into inorganic material for about 4 minutes. (Kamimura, M.)

337

Pneumatic moulding sand reclamation in the linear regenerator system  

OpenAIRE

This article covers the analysis of the pneumatic moulding sand reclamation, made of different types of binders. The research has been carried out for the sand with resin binder (phenolicformaldehyde and furan resins) as well as water glass (hardened with flodur and arconite hardener). Reclamation has been carried in the pneumatic conveying system in the linear regenerator in the technical scale. Evaluation of the effectiveness of the reclamation has been made on the basis of tests deter...

Szlumczyk, H.; Janerka, K.; Homa, D.; Myszor, A.

2007-01-01

338

Introduction of bridging and pendant organic groups into mesoporous alumina materials.  

Science.gov (United States)

Incorporation of organic functionalities into soft-templated mesoporous alumina was performed via organosilane-assisted evaporation induced self-assembly using aluminum alkoxide precursors and block copolymer templates. This strategy permits one to obtain mesoporous alumina-based materials with tailorable adsorption, surface and structural properties. Isocyanurate, ethane, mercaptopropyl, and ureidopropyl-functionalized mesoporous alumina materials were synthesized with relatively high surface area and large pore volume with uniform and wormhole-like mesopores. The presence of organosilyl groups within these hybrid materials was confirmed by IR or Raman spectroscopy and their concentration was determined by elemental analysis. PMID:21988174

Grant, Stacy M; Woods, Stephan M; Gericke, Arne; Jaroniec, Mietek

2011-11-01

339

Highly enhanced capacitance of MgO-templated mesoporous carbons in low temperature ionic liquids  

Science.gov (United States)

MgO-templated mesoporous carbons with high specific surface areas were employed for the electrode materials of electric double layer capacitors (EDLCs) in low temperature ionic liquids. The mesoporous carbons exhibit strongly enhanced capacitance in ionic liquids at 20 to -40 °C compared to conventional activated carbons. Mesopores in the carbon electrodes provide a smooth pathway for the ions, and minimize the temperature influence on the diffusion resistance of the ions. Thus, this paper confirms that mesoporous carbons work as electrode materials to achieve highly enhanced capacitances below 0 °C in ionic liquids, which leads to wide ranging applications of EDLC devices.

Kado, Yuya; Imoto, Kiyoaki; Soneda, Yasushi; Yoshizawa, Noriko

2014-12-01

340

Mesoporous hexagonal Co3O4 for high performance lithium ion batteries  

OpenAIRE

Mesoporous Co3O4 nanoplates were successfully prepared by the conversion of hexagonal ?-Co(OH)2 nanoplates. TEM, HRTEM and N2 sorption analysis confirmed the facet crystal structure and inner mesoporous architecture. When applied as anode materials for lithium storage in lithium ion batteries, mesoporous Co3O4 nanocrystals delivered a high specific capacity. At 10?C current rate, as-prepared mesoporous Co3O4 nanoplates delivered a specific capacity of 1203?mAh/g at first cycle and after ...

Su, Dawei; Xie, Xiuqiang; Munroe, Paul; Dou, Shixue; Wang, Guoxiu

2014-01-01

341

Magnetic nanocomposite spinel and FeCo core-shell and mesoporous systems  

International Nuclear Information System (INIS)

The fabrication of condensed silica and mesoporous silica coated spinel CoFe2O4 and FeCo alloy magnetic nanocomposites are reported. The encapsulation of well-defined 5 nm thick uniform silica layer on CoFe2O4 magnetic nanoparticles was performed. The formation of mesopores in the shell was a consequence of removal of organic group of the precursor through annealing. The NiO nanoparticles were loaded into the mesoporous silica. The mesoporous silica shells leads to a larger coercivity than that of pure CoFe2O4 magnetic nanoparticles due to the decrease of interparticle interactions and magneto-elastic anisotropy. In addition, the FeCo nanoparticles were coated by condensed and mesoporous silica. The condensed silica can protect the reactive FeCo alloy from oxidation up to 300 °C. However, saturation magnetization of FeCo nanoparticles coated by silica after 400 °C annealing is dramatically decreased due to the oxidation of the FeCo core. The mesoporous silica coated magnetic nanostructure loaded with NiO as a final product could be used in the field of biomedical applications. - Highlights: ? We fabricated condensed and mesoporous silica coated magnetic nanocomposites. ? NiO nanoparticles were loaded into the mesoporous silica. ? Mesoporous silica shells leads to a larger coercivity. ? Silica-coated FeCo nanoparticles oxidize beyond 300 °C.

342

Study on Bismaleimide Modified TDE-86 Epoxy Resin  

Directory of Open Access Journals (Sweden)

Full Text Available In the study, BMI was modified by Ortho-diallyl Bisphenol A under certain conditions and got performed polymer. Epoxy resin was modified by the performed polymer using nadic methyl anhydride (MNA as curing agent. The study investigated the manufacturability, thermal and mechanical properties of modified resin. The manufacturability of the modified resin was indicated by viscosity- temperature, viscosity- time and the gel time curves. Thermal properties of modified resin were characterized by means of dynamic mechanical analysis (DMA. According to per GB/T standard, mechanical properties of resin casting body like impact strength and tensile strength were tested. The results demonstrated that the viscosity of modified resin is below 200mPa.s at 60°C and the gel time is 110mins at 120°C. The modified resin can be used in the resin transfer moulding (RTM process of all kinds of complex structural composites. The incorporation of the performed polymer improves the heat resistance of epoxy resin. The glass transition temperature (Tg of the modified epoxy resin is 201.2°C and improves 44°C. The impact strength of the modified epoxy resin is 8.061KJ/m2. The tensile strength and tensile modulu of the modified are 60.9MPa and 3.89GPa. The present paper observed electron micrographs of impact fracture cross-section of modified resin systems. The results showed that the fracture of the modified resin is ductile fracture.

Daofang Shi

2010-03-01

343

Morphological Control of Multifunctional Mesoporous Silica Nanomaterials for Catalysis Applications  

Energy Technology Data Exchange (ETDEWEB)

I found an efficient method to control the morphology of the organically monofunctionalized mesoporous silica materials by introducing different types of organoalkoxysilanes in a base-catalyzed co-condensation reaction. The monofunctionalized materials exhibit different particle morphologies relative to the pure MCM-41 material. The concentration dependence of the morphology is a critical factor to determine the final particle shape. A proposed mechanism of the shape evolution is also offered. After understanding the role of organoalkoxysilanes in producing various well-shaped nanomaterials, I also obtained a series of bifunctional mesoporous silica materials with certain particle morphology. A series of bifunctional mesoporous silica nanospheres (MSNs) whose physicochemical properties was investigated via solid state NMR techniques and Cu{sup 2+} adsorption capacity tests, The ratio of two different organic groups inside of mesopores of these MSNs could be fine-tuned. These MSNs serve as a useful model system to study substrate selectivity in catalytic reactions and sorption phenomena. For example, the Cu{sup 2+} adsorption capacity of these materials was dictated by the chemical nature of the mesopores generated by the different organic functional groups. An investigation of the substrate selectivity of the bifunctionalized MSNs in a competitive nitroaldol reaction using an equimolar amount of two competing 4-nitrobenzaldehyde derivatives was performed. Shape-controlled bifunctional MSNs were employed as the catalysts. The properties of the MSNs were investigated using various spectroscopic methods and electron microscopy. The more hydrophobic the surface organic groups are, the higher the ratio of hydrophobic final product. This is the first example to demonstrate the selection of substrate using physicochemical nature of the mesopore surface other than the conventional shape selection in zeolite systems. I also created a cooperative dual catalyst system that is capable of activating two different substrates in aldol reaction, Henry reaction and cyanosilylation. One catalytic group activates the nucleophile, another organic group simultaneously activates the electrophile to enhance the total reaction rate. I systematically vaned the amount of two organic groups and performed the three model reactions to compare rate enhancements.

Seong Huh

2004-12-19

344

Large-Scale, Three-Dimensional, Free-Standing, and Mesoporous Metal Oxide Networks for High-Performance Photocatalysis  

Science.gov (United States)

Mesoporous nanostructures represent a unique class of photocatalysts with many applications, including splitting of water, degradation of organic contaminants, and reduction of carbon dioxide. In this work, we report a general Lewis acid catalytic template route for the high-yield producing single- and multi-component large-scale three-dimensional (3D) mesoporous metal oxide networks. The large-scale 3D mesoporous metal oxide networks possess large macroscopic scale (millimeter-sized) and mesoporous nanostructure with huge pore volume and large surface exposure area. This method also can be used for the synthesis of large-scale 3D macro/mesoporous hierarchical porous materials and noble metal nanoparticles loaded 3D mesoporous networks. Photocatalytic degradation of Azo dyes demonstrated that the large-scale 3D mesoporous metal oxide networks enable high photocatalytic activity. The present synthetic method can serve as the new design concept for functional 3D mesoporous nanomaterials.

Bai, Hua; Li, Xinshi; Hu, Chao; Zhang, Xuan; Li, Junfang; Yan, Yan; Xi, Guangcheng

2013-07-01

345

Thermosetting resins for nuclear track detection  

International Nuclear Information System (INIS)

Several new thermosetting resins with a three dimensional network structure similar to that of CR-39 were polymerized to study their characteristics as nuclear track detectors. The comparison of the molecular structures of these resins gives us an important clue to develop highly sensitive polymeric track detectors. For example, butanediol bis allylcarbonate (BuAC) shows the sensitivity about ten times higher than diallyl and adipate (DAA). This suggests the carbonate groups in the BuAC molecule provide a much higher sensitivity than the ester groups in the DAA. During the course of this study, thermosetting resins with good etching properties and various sensitivities have been developed. Though the sensitivity of DAA is low, it will be useful for observations of ultra heavy cosmic rays and heavily ionizing particles at low energies. (author)

346

Immobilisation of ion exchange resins in cement  

International Nuclear Information System (INIS)

Over the last seven years, Low Oxidation State Metal Ion reagents (LOMI) have been used to decontaminate the 100 MW(e) Steam Generating Heavy Water Ractor (SGHWR) at Winfrith. The use of these reagents has resulted in a dilute ionic solution containing activation products which are produced by corrosion of metallic components in the reactor. It has been demonstrated that the amount of activity in the solution can be reduced using organic ion exchanger resins. These resins consist of a cross linked polystyrene with sulphonic acid or quaternary ammonium function groups and can be successfully immobilised in blended cement systems. The formulation which has been developed is produced from a 9 to 1 blend of ground granulated blast furnace slag (BFS) and ordinary Portland cement (OPC) containing 28% ion exchange resin in the water saturated form. If 6% Microsilica is added to the blended cement the waste loading can be increased to 36 w/o. (author)

347

Decontamination capability of epoxy resin coatings  

International Nuclear Information System (INIS)

The epoxy resin coatings with and without solvents, which have dominated nuclear technology applications, are being replaced more and more frequently by powerful two-component epoxy resin coatings which are emulsifiable with water. This replacement is required for reasons of environmental legislation. To assess the decontamination characteristics and the resistance to chemicals, these three systems were subjected to comparative studies without previous exposure and after gamma irradiation in steps up to 10 Gy. The investigations showed that coats emulsifiable with water performed as well as the solvent-bearing varieties. In this respect, they meet the criteria for coatings in nuclear plants according to the DIN 55991 Part 1 standard. The good properties, such as insensitivity to moisture in concrete, excellent adhesion and adhesion as intermediate layers also on old coatings, are going to help epoxy resin coatings emulsifiable with water win broad application in nuclear medicine and nuclear technology. (orig.)

348

Incineration of spent ion exchange resin  

International Nuclear Information System (INIS)

It is a pressing need to reduce radioactive waste which is generated from the maintenance and operation of a nuclear power plant. Incineration of low level combustible solid waste such as polyethylene seats, paper and others have been successfully performed since 1984 at the Shimane Nuclear Power Station. Furthermore, for extending incineration treatment to spent ion exchange resin, the incineration test was carried out in 1989. However, as the cation exchange resin contains sulfur and then incineration generates SOx gases, so the components of this facility will be in a corrosive environment. We surveyed incineration conditions to improve the corrosive environment at the exhaust gas treatment system. This paper includes these test results and improved method to incinerate spent ion exchange resin. (author)

349

Ion exchange resin for primary coolant cleanup  

International Nuclear Information System (INIS)

A treatment of once loading Fe ions and Cu ions to H type cationic exchange resins and then returning them to the H type is applied. This can promote a capturing process in the ion exchange resins, to improve the performance of eliminating insoluble particles. Accordingly, if the ion exchange resins applied with such a Fe/Cu loading treatment are used for primary coolants, fine particles which have been difficult to be eliminated so far can be efficiently eliminated and they are less introduced to the inside of a reactor. Accordingly, accumulated radioactivity in the reactor and scales on fuel rods are decreased, to reduce exposure dose. Further, since large-scaled facilities such as conventional prefilters can be reduced greatly or are no more necessary, costs for them can be saved. (T.M.)

350

Adsorption of plant phenols by polystyrene resins  

Directory of Open Access Journals (Sweden)

Full Text Available Adsorption of nine plant phenols by nine polystyrene ion-exchange resins was investigated in an experimental model system. The phenols were adsorbed by Amberlite CG-120 more efficiently than any other acidically charged resins tested in this study. They were also taken up by anion exchangers. Among them Dowex 1-X8 was found to show the strongest effect on the adsorption of the phenolic constituents applied. A comparison of the efficiency of plant phenol adsorption between two different types of the synthetic polymers revealed that the basically charged polystyrenes had more prefarable affinities for phenols than cation exchangers. For example, the ratio of the efficiency between Amberlite CG-120 and Dowex 1-X8 was roughly calculated to be 3:7 under the present experimental conditions. The adsorption rate of the test phenols was raised mostly by increasing the amount of the resins added, if they were mixed with effective polymers in the incubation model system.

Akiyoshi Fukushima

1987-09-01

351

Vitrification of spent ion exchange resin from Korean NPPs  

International Nuclear Information System (INIS)

Spent resin is the main wet waste generated by nuclear power plants (NPPs). Vitrification is conceptually attractive because of the potential durability of the final product and the large volume reduction. The vitrification of spent resin from NPPs is examined. There is a large amount of sulfate in spent resin ash. However, the limited solubility of sulfate in glass resulted in the low waste loading of spent resin. High sulfate in glass led to the phase separation. Some well-developed glasses frits have been used to vitrify spent resin from Korean NPPs. The waste loading is less than 5 wt percent of resin ash. Spent resin also was added to the borate waste glasses, 20 g of dry resin could be vitrified in 100 g of borate waste glass without phase separation and final waste from has good durability. (author). 12 refs., 6 tabs

352

Method of oxidative decomposition of radioactive ion exchange resin  

International Nuclear Information System (INIS)

In a case of decomposing weakly acidic ion exchange resins and weakly basic ion exchange resins, decomposition is extremely difficult as compared with a mixture of strongly acidic resins and strongly basic resins. In view of the above, when decomposing such mixed resin wastes formed upon using weakly acidic cationic exchange resins and weakly basic anionic exchange resins by using iron ions and copper ions as the catalyst and hydrogen peroxide as an oxidizer, acetic acid or acetate such as sodium acetate or calcium acetate is added to conduct oxidative decomposing treatment under the coexistence of acetic ions. Thus, OH radicals are formed from hydrogen peroxide and the catalyst and they react with acetate to promote the formation of organic radicals. Then, the resins are chemically attacked to destroy the structure thereby enabling to attain a high decomposition rate. (T.M.)

353

21 CFR 520.1242d - Levamisole resinate.  

Science.gov (United States)

... ). (3) Limitations. For pigs from weaning to market weight, mix one 58.1-gram packet of levamisole resinate containing...pounds of body weight as sole ration. For breeding swine, mix 1 packet of the 10-percent resinate in...

2010-04-01

354

Biphenyl liquid crystalline epoxy resin as a low-shrinkage resin-based dental restorative nanocomposite.  

Science.gov (United States)

Low-shrinkage resin-based photocurable liquid crystalline epoxy nanocomposite has been investigated with regard to its application as a dental restoration material. The nanocomposite consists of an organic matrix and an inorganic reinforcing filler. The organic matrix is made of liquid crystalline biphenyl epoxy resin (BP), an epoxy resin consisting of cyclohexylmethyl-3,4-epoxycyclohexanecarboxylate (ECH), the photoinitiator 4-octylphenyl phenyliodonium hexafluoroantimonate and the photosensitizer champhorquinone. The inorganic filler is silica nanoparticles (?70-100 nm). The nanoparticles were modified by an epoxy silane of ?-glycidoxypropyltrimethoxysilane to be compatible with the organic matrix and to chemically bond with the organic matrix after photo curing. By incorporating the BP liquid crystalline (LC) epoxy resin into conventional ECH epoxy resin, the nanocomposite has improved hardness, flexural modulus, water absorption and coefficient of thermal expansion. Although the incorporation of silica filler may dilute the reinforcing effect of crystalline BP, a high silica filler content (?42 vol.%) was found to increase the physical and chemical properties of the nanocomposite due to the formation of unique microstructures. The microstructure of nanoparticle embedded layers was observed in the nanocomposite using scanning and transmission electron microscopy. This unique microstructure indicates that the crystalline BP and nanoparticles support each other and result in outstanding mechanical properties. The crystalline BP in the LC epoxy resin-based nanocomposite was partially melted during exothermic photopolymerization, and the resin expanded via an order-to-disorder transition. Thus, the post-gelation shrinkage of the LC epoxy resin-based nanocomposite is greatly reduced, ?50.6% less than in commercialized methacrylate resin-based composites. This LC epoxy nanocomposite demonstrates good physical and chemical properties and good biocompatibility, comparable to commercialized composites. The results indicate that this novel LC nanocomposite is worthy of development and has potential for further applications in clinical dentistry. PMID:22842038

Hsu, Sheng-Hao; Chen, Rung-Shu; Chang, Yuan-Ling; Chen, Min-Huey; Cheng, Kuo-Chung; Su, Wei-Fang

2012-11-01

355

The influence of resin flexural modulus on the magnitude of ceramic strengthening.  

LENUS (Irish Health Repository)

The aim was to determine the magnitude of ceramic resin-strengthening with resin-based materials with varying flexural moduli using a regression technique to assess the theoretical strengthening at a \\'zero\\' resin-coating thickness. The hypothesis tested was that experimentally, increasing resin flexural modulus results in increased resin-strengthening observed at a theoretical \\'zero\\' resin-coating thickness.

Fleming, Garry J P

2012-07-01

356

Treatment of spent ion-exchange resins by incorporation into epoxy resin  

International Nuclear Information System (INIS)

Epoxy resin was used as an incorporation medium for inactive and labelled simulated spent ion-exchange resin. The quality of the final waste form has been defined using mechanical, thermal and homogeneity tests. Irradiation stability was studied by treating the end product with increasing doses before subjecting to mechanical tests. As for as the thermal stability is concerned, degradation occurs only above 280 C as shown by T G, DTG and DTA curves. The cumulative teach fractions were higher for both Ru-106 and Cs 137 than for Ce 144 labelled incorporated ion-exchange resin.2 tab., 5 fig

357

Radiation resistance of synthetic resin cements  

International Nuclear Information System (INIS)

A long-term irradiation test period of over a year showed a linear reduction of the flexural strength with radiation dose at a half-value dose of 7 MJ/kg for an amine hardened epoxide resin cement. The flexural strength of a peroxide-hardened unsaturated polyester resin cement was on the other hand negligibly changed by a dose of 7 MJ/kg. This cement mass is hence particularly suitable for filling water tanks for the storage of radioactive sources and for other applications in nuclear technology. (orig.)

358

Thermal behavior of halogenated imidebismaleimide resins  

International Nuclear Information System (INIS)

Several new poly-halogenated malecimides, bismaleimides and therir copoly resins were synthessised thermally from their corresponding amic acids. The synthesis was accomplished by two way method (amic acid-polimide) instead of the well-known three way method (amic acid-imide-polyimide). Thermal characterization of monomers and their cured resins was achieved using differential thermal analysis (DTA), dynamic thermogravimetric analysis (TGA) and isothermal gravimetric analysis (IGA). The effect of halogen substituent, especially in the ortho postion, is clear in the imidization proces, while polymerization proceeds almost equally in all systems. Thermal properties of homo and copolymers were correlated with their chemical structures. (author). 15 refs., 4

359

Performances and improvement of copper-hydrazine complexation deoxidising resin  

International Nuclear Information System (INIS)

Copper-hydrazine complexation deoxidising resin is tested to examine its performances including effluent water quality and capacity of deoxidisation. By the means of changing the resin type and regeneration, the deoxidising capacity of the resin can be improved to 13 times more than before. At the same time, physical performances of the resin are also greatly improved while maintaining its velocity of deoxidisation and effluent quality. (authors)

360

Gamma-irradiation on cured glycidyl amino-epoxy resin  

International Nuclear Information System (INIS)

ITER is an international project to design and build an experimental fusion reactor based on the superconductive 'tokamak' concept. Amounts of epoxy resin are used in the superconductive tokamak device as impregnant resins, insulation breaks, etc. Resistance to ionizing radiation is a demanding performance of those epoxy resins. In this work, we study the effects of ?-irradiation on the mechanical properties and chemical structures of glycidyl amino-epoxy resins

361

Development of treatment system for radioactive spent ion exchange resins  

International Nuclear Information System (INIS)

A new ion exchange resin solidification system, featuring the combining of resins with paraffin wax, has been developed. The resulting solid matter, constituting resins and paraffin wax, were able to be easily incinerated at existing incineration plants. Therefore, there is no longer a need to store spent ion exchange resins, as low-level radioactive waste, that had been output from water purification systems at nuclear power plants. (author)

362

Synthesis and Thermal Degradation Studies of Melamine Formaldehyde Resins  

OpenAIRE

Melamine formaldehyde (MF) resins have been synthesized at different reaction temperature and pH values. Different molar ratios of melamine and formaldehyde were used to synthesize the corresponding resins. The prepared resin samples were characterized by using molecular weight determination viscometry and thermogravimetric analysis (TGA). The maximum percentage of solid content (69.7%) was obtained at pH 8.5 and 75°C temperature. The molecular weight of MF resin was increased with an increa...

Sami Ullah; Bustam, M. A.; Nadeem, M.; Naz, M. Y.; Tan, W. L.; Shariff, A. M.

2014-01-01

363

Evaluation of cure shrinkage measurement techniques for thermosetting resins  

OpenAIRE

Resin chemical shrinkage dictates the surface integrity and the roughness of a composite structure. Thus, to minimize surface failures and to produce a good surface quality it is a requisite to be able to measure and track resin shrinkage during the cure process. This manuscript investigates and evaluates the measuring and monitoring of real-time resin shrinkage using a rheometer, a helium-based pycnometer and a thermo-mechanical analyzer (TMA) for ambient curing UP and epoxy resins. Shrinkag...

Shah, Darshil U.; Schubel, Peter J.

2010-01-01

364

Chemoradiotherapeutic wrinkled mesoporous silica nanoparticles for use in cancer therapy  

Energy Technology Data Exchange (ETDEWEB)

Over the last decade, the development and application of nanotechnology in cancer detection, diagnosis, and therapy have been widely reported. Engineering of vehicles for the simultaneous delivery of chemo- and radiotherapeutics increases the effectiveness of the therapy and reduces the dosage of each individual drug required to produce an observable therapeutic response. We here developed a novel chemoradiotherapeutic 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid coated/uncoated platinum drug loaded, holmium-containing, wrinkled mesoporous silica nanoparticle. The materials were characterized with TEM, FTIR, {sup 1}H NMR, energy dispersive x-ray, inductively coupled plasma-mass spectrometry, and zeta potential measurements. In vitro platinum drug release from both lipid coated and uncoated chemoradiotherapeutic wrinkled mesoporous silica are reported. Various kinetic models were used to analyze the release kinetics. The radioactivity of the chemoradiotherapeutic nanocarriers was measured after neutron-activation.

Munaweera, Imalka; Balkus, Kenneth J. Jr., E-mail: Balkus@utdallas.edu, E-mail: Anthony.DiPasqua@unthsc.edu [Department of Chemistry, University of Texas at Dallas, 800 West Campbell Rd., Richardson, Texas 75080 (United States); Koneru, Bhuvaneswari; Shi, Yi; Di Pasqua, Anthony J., E-mail: Balkus@utdallas.edu, E-mail: Anthony.DiPasqua@unthsc.edu [Department of Pharmaceutical Sciences, University of North Texas System College of Pharmacy, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, Texas 76107 (United States)

2014-11-01

365

Chemoradiotherapeutic wrinkled mesoporous silica nanoparticles for use in cancer therapy  

Science.gov (United States)

Over the last decade, the development and application of nanotechnology in cancer detection, diagnosis, and therapy have been widely reported. Engineering of vehicles for the simultaneous delivery of chemo- and radiotherapeutics increases the effectiveness of the therapy and reduces the dosage of each individual drug required to produce an observable therapeutic response. We here developed a novel chemoradiotherapeutic 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid coated/uncoated platinum drug loaded, holmium-containing, wrinkled mesoporous silica nanoparticle. The materials were characterized with TEM, FTIR, 1H NMR, energy dispersive x-ray, inductively coupled plasma-mass spectrometry, and zeta potential measurements. In vitro platinum drug release from both lipid coated and uncoated chemoradiotherapeutic wrinkled mesoporous silica are reported. Various kinetic models were used to analyze the release kinetics. The radioactivity of the chemoradiotherapeutic nanocarriers was measured after neutron-activation.

Munaweera, Imalka; Koneru, Bhuvaneswari; Shi, Yi; Di Pasqua, Anthony J.; Balkus, Kenneth J., Jr.

2014-11-01

366

Synthesis of Mesoporous Carbon Using Halloyiste As Template  

Directory of Open Access Journals (Sweden)

Full Text Available Mesoporous carbons withcore-shellstructure were synthesized using halloysite as template and sucrose as carbon precursor by a template method. Field-emission scanning electron microscope (FE-SEM, transmission electron microscope (TEM, nitrogen adsorption, X-ray diffraction, Raman spectra and Thermogravimetry (TG were employed to cheracterize the as-synthesized materials. Results indicate that the morphology and structure of the templated carbons are similar to that of halloysite. The carbons exhibit higher specific surface area (945 m2/g and 1147 m2/g, higher pore volumes and mesopore volume fraction than that of halloysite. The carbons present high purity and amorphous structure. Raising the carbonization temperature, the Raman characteristic parameter (R of the carbons decreases and their decomposition temperature increases from 563°C to 623°C. At the same time, the formation mechanism of the carbons and their pores is also discussed.

ZHOU Shu-Hui, CHUAN Xiu-Yun

2014-06-01

367

Mesoporous material Al-MCM-41 from natural halloysite  

Science.gov (United States)

Aluminum-containing hexagonally ordered mesoporous silica (Al-MCM-41) with specific surface area of 509.4 m2/g was first synthesized using natural halloysite as source material by hydrothermal treatment, without addition of silica or aluminum regents. The samples were characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption measurements, and Fourier transform infrared spectra techniques. The results indicate that process parameters, including calcination temperature, pH value, n(SiO2)/ n(CTAB)/ n(H2O) ratio, and hydrothermal reaction time, show moderate effects on the preparation of Al-MCM-41. SiO2/Al2O3 molar ratio could be effectively modulated by the calcination temperature for halloysite. Furthermore, we first clarified the structural evolution from natural halloysite to mesoporous material Al-MCM-41 at the atomic level.

Xie, Yaling; Zhang, Yi; Ouyang, Jing; Yang, Huaming

2014-07-01

368

Synthesis and characterization of acidic mesoporous borosilicate thin films.  

Science.gov (United States)

Work on the synthesis and characterization of acidic wormhole-like ordered mesoporous borosilicate thin films (MBSTFs) on silicon wafers is described in this paper. The MBSTFs coated by the dip-coating method were prepared through an evaporation-induced self-assembly (EISA) process using nonionic block copolymers as structure-directing agents. Fourier transform infrared (FT-IR) spectroscopy confirmed the formation of borosiloxane bonds (Si-O-B). High-resolution transmission electron microscopy (HRTEM) and N2 sorption evidenced a wormhole-like mesoporous structure in the MBSTFs obtained. Scanning electron microscopy (SEM) images of the cross sections and surfaces of the samples showed that MBSTFs on silicon wafers were continuous, homogeneous and did not crack. The acidic properties of the MBSTFs were characterized by FT-IR spectra of chemisorbed pyridine. The MBSTFs thus prepared may find their future applications in many fields including chemical sensors, catalysis, optical coating, molecule separation, etc. PMID:19441565

Xiu, Tongping; Liu, Qian; Wang, Jiacheng

2009-02-01

369

Adsorption of benzene, cyclohexane and hexane on ordered mesoporous carbon.  

Science.gov (United States)

Ordered mesoporous carbon (OMC) with high specific surface area and large pore volume was synthesized and tested for use as an adsorbent for volatile organic compound (VOC) disposal. Benzene, cyclohexane and hexane were selected as typical adsorbates due to their different molecular sizes and extensive utilization in industrial processes. In spite of their structural differences, high adsorption amounts were achieved for all three adsorbates, as the pore size of OMC is large enough for the access of these VOCs. In addition, the unusual bimodal-like pore size distribution gives the adsorbates a higher diffusion rate compared with conventional adsorbents such as activated carbon and carbon molecular sieve. Kinetic analysis suggests that the adsorption barriers mainly originated from the difficulty of VOC vapor molecules entering the pore channels of adsorbents. Therefore, its superior adsorption ability toward VOCs, together with a high diffusion rate, makes the ordered mesoporous carbon a promising potential adsorbent for VOC disposal. PMID:25872710

Wang, Gang; Dou, Baojuan; Zhang, Zhongshen; Wang, Junhui; Liu, Haier; Hao, Zhengping

2015-04-01

370

Designing advanced functional periodic mesoporous organosilicas for biomedical applications  

Directory of Open Access Journals (Sweden)

Full Text Available Periodic mesoporous organosilicas (PMOs, reported for the first time in 1999, constitute a new branch of organic-inorganic hybrid materials with high-ordered structures, uniform pore size and homogenous distribution of organic bridges into a silica framework. Unlike conventional mesoporous silicas, these materials offer the possibility to adjust the surface (hydrophilicity/hydrophobicity and physical properties (morphology, porosity as well as their mechanical stability through the incorporation of different functional organic moieties in their pore walls. A broad variety of PMOs has been designed for their subsequent application in many fields. More recently, PMOs have attracted growing interest in emerging areas as biology and biomedicine. This review provides a comprehensive overview of the most recent breakthroughs achieved for PMOs in biological and biomedical applications.

Dolores Esquivel

2014-03-01

371

Fluorescent Functionalized Mesoporous Silica for Radioactive Material Extraction  

Energy Technology Data Exchange (ETDEWEB)

Mesoporous silica with covalently bound salicylic acid molecules incorporated in the structure was synthesized with a one-pot, co-condensation reaction at room temperature. The as-synthesized material has a large surface area, uniform particle size, and an ordered pore structure as determined by characterization with transmission electron microscopy, thermal gravimetric analysis, and infrared spectra, etc. Using the strong fluorescence and metal coordination capability of salicylic acid, functionalized mesoporous silica (FMS) was developed to track and extract radionuclide contaminants, such as uranyl [U(VI)] ions encountered in subsurface environments. Adsorption measurements showed a strong affinity of the FMS toward U(VI) with a Kd value of 105 mL/g, which is four orders of magnitude higher than the adsorption of U(VI) onto most of the sediments in natural environments. The new materials have a potential for synergistic environmental monitoring and remediation of the radionuclide U(VI) from contaminated subsurface environments.

Li, Juan; Zhu, Kake; Shang, Jianying; Wang, Donghai; Nie, Zimin; Guo, Ruisong; Liu, Chongxuan; Wang, Zheming; Li, Xiaolin; Liu, Jun

2012-08-01

372

Chemoradiotherapeutic wrinkled mesoporous silica nanoparticles for use in cancer therapy  

International Nuclear Information System (INIS)

Over the last decade, the development and application of nanotechnology in cancer detection, diagnosis, and therapy have been widely reported. Engineering of vehicles for the simultaneous delivery of chemo- and radiotherapeutics increases the effectiveness of the therapy and reduces the dosage of each individual drug required to produce an observable therapeutic response. We here developed a novel chemoradiotherapeutic 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid coated/uncoated platinum drug loaded, holmium-containing, wrinkled mesoporous silica nanoparticle. The materials were characterized with TEM, FTIR, 1H NMR, energy dispersive x-ray, inductively coupled plasma-mass spectrometry, and zeta potential measurements. In vitro platinum drug release from both lipid coated and uncoated chemoradiotherapeutic wrinkled mesoporous silica are reported. Various kinetic models were used to analyze the release kinetics. The radioactivity of the chemoradiotherapeutic nanocarriers was measured after neutron-activation

373

Natural dye -sensitized mesoporous ZnO solar cell  

Science.gov (United States)

Natural dye-sensitized solar cells (N-DSSCs) were assembled using chlorophyll sensitized mesoporous ZnO (based on FTO) as the photoanode and platinum plate as the cathode. The natural dyes (chlorophyll) were extracted from spinach by simple procedure. The absorption spectrum and fluorescence spectrum of chlorophyll were studied. Mesoporous ZnO (m-ZnO) applied to the N-DSSCs was synthesized through hydrothermal method. The structures and morphologies were characterized by X-ray Diffraction (XRD) and diffuse reflection. The results indicated that the samples had an average pore size of 17 nm and the m-ZnO was hexagonal wurtzite structure. The performances of the N-DSSCs were investigated under AM 1.5G illumination. The Voc of the N-DSSCs was about 480mv, and the Isc was about 470?A. The performance of the N-DSSCs could be further improved by adjusting its structure.

Wu, Qishuang; Shen, Yue; Wu, Guizhi; Li, Linyu; Cao, Meng; Gu, Feng

2011-02-01

374

Flash freezing route to mesoporous polymer nanofibre networks  

Science.gov (United States)

There are increasing requirements worldwide for advanced separation materials with applications in environmental protection processes. Various mesoporous polymeric materials have been developed and they are considered as potential candidates. It is still challenging, however, to develop economically viable and durable separation materials from low-cost, mass-produced materials. Here we report the fabrication of a nanofibrous network structure from common polymers, based on a microphase separation technique from frozen polymer solutions. The resulting polymer nanofibre networks exhibit large free surface areas, exceeding 300?m2?g-1, as well as small pore radii as low as 1.9?nm. These mesoporous polymer materials are able to rapidly adsorb and desorb a large amount of carbon dioxide and are also capable of condensing organic vapours. Furthermore, the nanofibres made of engineering plastics with high glass transition temperatures over 200?°C exhibit surprisingly high, temperature-dependent adsorption of organic solvents from aqueous solution.

Samitsu, Sadaki; Zhang, Rui; Peng, Xinsheng; Krishnan, Mohan Raj; Fujii, Yoshihisa; Ichinose, Izumi

2013-10-01

375

Chemoradiotherapeutic wrinkled mesoporous silica nanoparticles for use in cancer therapy  

Directory of Open Access Journals (Sweden)

Full Text Available Over the last decade, the development and application of nanotechnology in cancer detection, diagnosis, and therapy have been widely reported. Engineering of vehicles for the simultaneous delivery of chemo- and radiotherapeutics increases the effectiveness of the therapy and reduces the dosage of each individual drug required to produce an observable therapeutic response. We here developed a novel chemoradiotherapeutic 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid coated/uncoated platinum drug loaded, holmium-containing, wrinkled mesoporous silica nanoparticle. The materials were characterized with TEM, FTIR, 1H NMR, energy dispersive x-ray, inductively coupled plasma-mass spectrometry, and zeta potential measurements. In vitro platinum drug release from both lipid coated and uncoated chemoradiotherapeutic wrinkled mesoporous silica are reported. Various kinetic models were used to analyze the release kinetics. The radioactivity of the chemoradiotherapeutic nanocarriers was measured after neutron-activation.

Imalka Munaweera

2014-11-01

376

Mesoporous multilayer thin films: environment-sensitive photonic crystals  

International Nuclear Information System (INIS)

Photonic Crystals made up of stacked mesoporous thin films (MTF) were produced by sequential deposition. These materials present order at different length scales: atomic (local structure), mesoscopic (ordered mesopores) and submicronic (controlled thickness), which were accurately assessed by Small Angle X-ray Scattering (2D SAXS, D11A SAXS1) and X-ray Reflectometry (XRR, D10A XRD2). Each MTF building block of a complex multilayer architecture behaves like an 'optical switch' in the presence of vapours. Its electronic density (and therefore the refractive index) changes due to capillary condensation of a given solvent within the pore systems. This allows for the creation of photonic crystals that are responsive to environment, with promising applications in selective sensing or active waveguides. (author)

377

Shaped platinum nanoparticles directly synthesized inside mesoporous silica supports  

Science.gov (United States)

It is difficult to deposit shape-controlled nanoparticles into a mesoporous framework while preserving the shape. For shaped platinum nanoparticles, which are typically 5-10 nm in size, capillary inclusion by sonication or the formation of a mesoporous framework around the shaped platinum nanoparticles has been attempted, but the nanoparticles aggregated or their shapes were degraded easily. In this work, we directly nucleated platinum on the surface inside a mesoporous silica support and controlled the overgrowth step, producing cubic shaped nanoparticles. Mercaptopropyltrimethoxysilane was used as an anchoring agent causing nucleation at the silica surface, and it also helped to shape the nanoparticles. Platinum nanocubes, which were synthesized with polymeric capping agents separately, were deposited inside the mesoporous silica by sonication, but most of the nanoparticles were clogged at the entrance to the pores, and the surface of the platinum had very few sites that were catalytically active, as evidenced by the small H2 uptake. Unshaped platinum nanoparticles, which were prepared by conventional wet impregnation, showed a similar amount of H2 uptake as the in situ shaped platinum cubes, but the selectivity for pyrrole hydrogenation was poorer towards the production of pyrrolidine. The mesoporosity and the residual thiol groups on the surface of the in situ shaped Pt nanocubes might cause a high selectivity for pyrrolidine.It is difficult to deposit shape-controlled nanoparticles into a mesoporous framework while preserving the shape. For shaped platinum nanoparticles, which are typically 5-10 nm in size, capillary inclusion by sonication or the formation of a mesoporous framework around the shaped platinum nanoparticles has been attempted, but the nanoparticles aggregated or their shapes were degraded easily. In this work, we directly nucleated platinum on the surface inside a mesoporous silica support and controlled the overgrowth step, producing cubic shaped nanoparticles. Mercaptopropyltrimethoxysilane was used as an anchoring agent causing nucleation at the silica surface, and it also helped to shape the nanoparticles. Platinum nanocubes, which were synthesized with polymeric capping agents separately, were deposited inside the mesoporous silica by sonication, but most of the nanoparticles were clogged at the entrance to the pores, and the surface of the platinum had very few sites that were catalytically active, as evidenced by the small H2 uptake. Unshaped platinum nanoparticles, which were prepared by conventional wet impregnation, showed a similar amount of H2 uptake as the in situ shaped platinum cubes, but the selectivity for pyrrole hydrogenation was poorer towards the production of pyrrolidine. The mesoporosity and the residual thiol groups on the surface of the in situ shaped Pt nanocubes might cause a high selectivity for pyrrolidine. Electronic supplementary information (ESI) available: Fig. S1-S9. See DOI: 10.1039/c4nr03951c

Kim, Jiwhan; Bae, Youn-Sang; Lee, Hyunjoo

2014-10-01

378

Noble Metal Nanoparticle-loaded Mesoporous Oxide Microspheres for Catalysis  

Science.gov (United States)

Noble metal nanoparticles/nanocrystals have attracted much attention as catalysts due to their unique characteristics, including high surface areas and well-controlled facets, which are not often possessed by their bulk counterparts. To avoid the loss of their catalytic activities brought about by their size and shape changes during catalytic reactions, noble metal nanoparticles/nanocrystals are usually dispersed and supported finely on solid oxide supports to prevent agglomeration, nanoparticle growth, and therefore the decrease in the total surface area. Moreover, metal oxide supports can also play important roles in catalytic reactions through the synergistic interactions with loaded metal nanoparticles/nanocrystals. In this thesis, I use ultrasonic aerosol spray to produce hybrid microspheres that are composed of noble metal nanoparticles/nanocrystals embedded in mesoporous metal oxide matrices. The mesoporous metal oxide structure allows for the fast diffusion of reactants and products as well as confining and supporting noble metal nanoparticles. I will first describe my studies on noble metal-loaded mesoporous oxide microspheres as catalysts. Three types of noble metals (Au, Pt, Pd) and three types of metal oxide substrates (TiO2, ZrO2, Al 2O3) were selected, because they are widely used for practical catalytic applications involved in environmental cleaning, pollution control, petrochemical, and pharmaceutical syntheses. By considering every possible combination of the noble metals and oxide substrates, nine types of catalyst samples were produced. I characterized the structures of these catalysts, including their sizes, morphologies, crystallinity, and porosities, and their catalytic performances by using a representative reduction reaction from nitrobenzene to aminobenzene. Comparison of the catalytic results reveals the effects of the different noble metals, their incorporation amounts, and oxide substrates on the catalytic abilities. For this particular reaction, I found that Pd nanoparticles supported on mesoporous TiO2 exhibit the best catalytic performance. The demonstrated low-cost and high-productivity preparation method can be extended to other catalysts, which can contain various metals and oxide substrates and will have high potential for industrial applications. Our preparation method also provides a platform for the studies of the synergetic catalytic effects between different oxide substrates and metals. I further fabricated hollow mesoporous microspheres containing differently shaped noble metal nanocrystals. Hollow structures are strongly desired in many applications because of their high pore volumes, surface areas, and possible light-trapping effect. In my study, the hollow structures were obtained by simply dispersing polystyrene (PS) nanospheres into the precursor solution for aerosol spray. The PS spheres were removed by thermal calcination to produce hollow mesoporous microspheres. In my first study, the noble metal salts were dissolved in the precursor solutions, and the noble metal nanoparticles were obtained through thermal calcination. In this way, the size and shape of the metal nanoparticles cannot be well controlled. In my second study, I first grew noble metal nanocrystals and then incorporated them into the oxide supports. This preparation route allowed me to incorporate metal nanocrystals with controlled sizes, shapes, and compositions into the oxide matrices. The metal nanocrystals I used in this experiment included Pd nanocubes, Au nanorods, and Au core--Pd shell nanorods. These nanocrystals were functionalized with thiol-terminated methoxypoly(ethylene glycol) . The surface functionalization allowed them to adsorb on the PS spheres. After thermal calcination, the noble metal nanocrystals were left inside and adsorbed on the inner surface of the hollow mesoporous metal oxide microspheres. I investigated the catalytic activities of the Pd nanocube-embedded hollow mesoporous TiO2 and ZrO2 microspheres for the reduction of 4-nitrophenol to 4-aminophenol. I also examined the recycla

Jin, Zhao

379

Enhancement of two-photon absorption in anisotropic mesoporous silicon  

International Nuclear Information System (INIS)

In experiments on nonlinear-optical transmission of picosecond laser pulses at the wavelength of 1.064 ?m three-order-of-magnitude enhancement of the photoinduced absorption in optically anisotropic mesoporous silicon films compared to crystalline silicon (c-Si) was found. The effect is not sensitive to the polarization of the laser radiation and it saturates at laser peak intensities about 5 MW/cm2. Higher laser intensity results in the polarization-sensitive photoinduced absorption, which is merely one-order-of-magnitude more effective than in c-Si. These efficient nonlinear-optical responses can be attributed to the resonant excitation of the defect states in the direct gap of silicon and local-field enhancement in the mesoporous films

380

Interconnected mesopores and high accessibility in UVM-7-like silicas  

Energy Technology Data Exchange (ETDEWEB)

Nanoparticulated bimodal mesoporous silicas (NBS) have proved to constitute adequate supports in a variety of applications requiring enhanced accessibility to the active sites. Mass-transfer kinetics seems to be highly favoured in UVM-7-derived NBS materials. To understand the mass-diffusion phenomena throughout UVM-7-like supports requires well-grounded knowledge about their pore architecture. 3-D reconstructions of the UVM-7 mesostructure carried out by electron tomography reveal the existence of a true hierarchic connectivity involving both inter- and intra-nanoparticle pores. This connectivity makes self-supported nanoparticulated mesoporous bimodal carbon replicas of the supports feasible to obtaining by nanocasting. Both the temperature-induced mobility of gold nanodomains and the fast and efficient enzyme adsorption in UVM-7-like silicas are examples of non-constrained diffusion processes happening inside such an open network.

Perez-Cabero, Monica [Universitat de Valencia, Institut de Ciencia dels Materials (Spain); Hungria, Ana B. [Universidad de Cadiz, Departamento de Ciencia de Materiales, Ingenieria Metalurgica y Quimica Inorganica (Spain); Morales, Jose Manuel [Universitat de Valencia, Institut de Ciencia dels Materials (Spain); Tortajada, Marta; Ramon, Daniel [Biopolis S. L. (Spain); Moragues, Alaina; El Haskouri, Jamal; Beltran, Aurelio; Beltran, Daniel; Amoros, Pedro, E-mail: pedro.amoros@uv.es [Universitat de Valencia, Institut de Ciencia dels Materials (Spain)

2012-08-15

381

Liquid-phase synthesized mesoporous electrochemical supercapacitors of nickel hydroxide  

International Nuclear Information System (INIS)

Electrochemical supercapacitive (ES) properties of liquid-phase synthesized mesoporous (pore size distribution centered ?12 nm) and of 120 m2/g surface area nickel hydroxide film electrodes onto tin-doped indium oxide substrate are discussed. The amounts of inner and outer charges are calculated to investigate the contribution of mesoporous structure on charge storage where relatively higher contribution of inner charge infers good ion diffusion into matrix of nickel hydroxide. Effect of different electrolytes, electrolyte concentrations, deposit mass and scan rates on the current-voltage profile in terms of the shape and enclosed area is investigated. Specific capacitance of ?85 F/g at a constant current density of 0.03 A/g is obtained from the discharge curve

382

Electrochemical detection of ultratrace nitroaromatic explosives using ordered mesoporous carbon.  

Science.gov (United States)

A sensitive electrochemical sensor has been fabricated to detect ultratrace nitroaromatic explosives using ordered mesoporous carbon (OMC). OMC was synthesized and characterized by scanning electron microscopy, transmission electron microscopy and nitrogen adsorption/desorption measurements. Glassy carbon electrodes functionalized with OMC show high sensitivity of 62.7 ?A cm(-2) per ppb towards 2,4,6-trinitrotoluene (TNT). By comparison with other materials such as carbon nanotubes and ordered mesoporous silica, it is found that the high performance of OMC toward sensing TNT is attributed to its large specific surface area and fast electron transfer capability. As low as 0.2 ppb TNT, 1 ppb 2,4-dinitrotoluene and 1 ppb 1,3-dinitrobenzene can be detected on OMC based electrodes. This work renders new opportunities to detect ultratrace explosives for applications of environment protections and home securities against chemical warfare agents. PMID:21167969

Zang, Jianfeng; Guo, Chun Xian; Hu, Fengping; Yu, Lei; Li, Chang Ming

2011-01-10

383

Curing reaction of bisphenol-A based benzoxazine with cyanate ester resin and the properties of the cured thermosetting resin  

Directory of Open Access Journals (Sweden)

Full Text Available Curing reaction of bisphenol-A based benzoxazine with cyanate ester resin and the properties of the cured thermosetting resin were investigated. The cure behavior of benzoxazine with cyanate ester resin was monitored by model reaction using nuclear magnetic resonance (NMR. As a result of the model reaction, the ring opening reaction of benzoxazine ring and thermal self-cyclotrimerization of cyanate ester group occurred, and then the phenolic hydoroxyl group generated by the ring opening reaction of benzoxazine ring co-reacted with cyanate ester group. The properties of the cured thermosetting resin were estimated by mechanical properties, electrical resistivity, water resistance and heat resistance. The cured thermosetting resin from benzoxazine and cyanate ester resin showed good heat resistance, high electrical resistivity and high water resistance, compared with the cured thermosetting resin from benzoxazine and epoxy resin.

H. Kimura

2011-12-01

384

Photosensitive filler minimizes internal stresses in epoxy resins  

Science.gov (United States)

Photosensitive filler is added to curable epoxy resins to minimize stress from internal shrinkage during curing or polymerization. Cinnamic acid resins and cinnamal ketones may be added in the amount of 1 to 3 percent by weight of the resin mixture.

Dillon, J. N.

1967-01-01

385

Electron sensitive resin and fabrication process of this one  

International Nuclear Information System (INIS)

The invention concerns electron sensitive negative resins, that is to say the resins which, when subjected to the action of an electronic beam of adequate power, undergo a transformation that makes them resistant to certain chemical agents or insoluble in certain solvents. The invention also concerns a process for manufacturing this resin which is a 2.3 epithiopropylmethacrylate copolymer

386

Occupational asthma due to unheated polyvinylchloride resin dust.  

OpenAIRE

Polyvinylchloride (PVC) resins are widely used in industry. Asthma due to the thermal degradation products of PVC are well documented. In this first case of occupational asthma due to unheated PVC resin dust the patient was exposed to PVC resin dust during the mixing of chemicals used for making plastic seals for bottle caps.

Lee, H. S.; Yap, J.; Wang, Y. T.; Lee, C. S.; Tan, K. T.; Poh, S. C.

1989-01-01

387

Solid-phase synthesis of isoalloxazines using merrifield resin  

International Nuclear Information System (INIS)

The reaction of Merrifield resin bound diamino compounds with alloxan monohydrate gave 7- resin bound 10-substituted isoalloxazines that were characterized by solid phase fluorescence and IR spectroscopy. The resin was cleaved by 40% aqueous HF/DMF to give 7-carboxy-10-substituted isoalloxazines that were characterized by UV-vis., IR, 1H NMR, fluorescence and elemental analysis. (author)

388

An oxidizing resin for iodine-labelled pharmaceuticals  

International Nuclear Information System (INIS)

A chloramine oxidizing resin has been prepared using nylon-6 as monomeric unit and by the method of substituting hydrogen by active chlorine (Cl+) in hypochlorous acid. The synthesis, oxidizing characteristics and applications in iodire-labelled pharmaceuticals of the resin are described. A labelling rate of 96% has been obtained for labelled 125I-iodocholesterol by using this resin

389

Development of radiation-curable resin based on natural rubber  

International Nuclear Information System (INIS)

A new radiation curable resin based on natural rubber has been developed. The resin was based on the reaction between low molecular weight epoxidised natural rubber and acrylic acid. When formulated with reactive monomers and photoinitiator, it solidified upon irradiation with UV light. The resin may find applications in coating for cellulosic-based substrates and pressure-sensitive adhesive

390

In Mesopore Protein Digestion: A New Forthcoming Strategy in Proteomics  

OpenAIRE

The conventional protocols for in solution or in gel protein digestion require many steps and long reaction times. The use of trypsin immobilized onto solid supports has recently captured the attention of many research groups, because these systems can speed-up protein digestion significantly. The utilization of new materials such as mesoporous silica as supports, in which enzyme and substrate are dramatically concentrated and confined in the nanospace, offers new opportunities to reduce the ...

Rosa Terracciano; Rocco Savino; Francesca Casadonte

2011-01-01

391

A High Temperature Capacitive Humidity Sensor Based on Mesoporous Silica  

OpenAIRE

Capacitive sensors are the most commonly used devices for the detection of humidity because they are inexpensive and the detection mechanism is very specific for humidity. However, especially for industrial processes, there is a lack of dielectrics that are stable at high temperature (>200 °C) and under harsh conditions. We present a capacitive sensor based on mesoporous silica as the dielectric in a simple sensor design based on pressed silica pellets. Investigation of the structural sta...

Michael Tiemann; Jan Roggenbuck; Sören Krotzky; Claus-Dieter Kohl; Tilman Sauerwald; Alexander Weiß; Thorsten Wagner

2011-01-01

392

Mesoporous silicon nitride for reversible CO2 capture.  

OpenAIRE

A good catch of CO 2! It is demonstrated for the first time that a high-surface-area, inorganic-based mesoporous silicon nitride prepared through a precipitation-sublimation route shows a high, reversible CO 2 uptake over a wide temperature range (298-423 K) with a moderate heat of adsorption. Our data render the thermally stable material a new contender for practical CO 2 capture. © 2012 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim.

Yang, H.; Khan, Am; Yuan, Y.; Tsang, Sc

2012-01-01

393

Hybrid Photonic Antennae Based on Mesoporous Silica Frameworks  

OpenAIRE

This contribution describes design, preparation and physico-chemical characterization of a new photo-stable hybrid antenna based on mesoporous SBA-15 silica. Concepts of host-guest chemistry are applied in such a way that one or more photoactive guest molecules are incorporated into the silica channels and on the outer surface, acting as energy harvesting and transferring units. The presented composite system be-haves as efficient Förster resonance energy transfer (FRET) pair and shows high ...

Cucinotta F; Carniato F.; Marchese L.

2013-01-01

394

Oxidative nanopatterning of titanium generates mesoporous surfaces with antimicrobial properties  

OpenAIRE

Fabio Variola,1,2 Sylvia Francis Zalzal,3 Annie Leduc,3 Jean Barbeau,3 Antonio Nanci31Faculty of Engineering, Department of Mechanical Engineering, 2Faculty of Science, Department of Physics, University of Ottawa, Ottawa, ON, 3Faculty of Dental Medicine, Université de Montréal, Montreal, QC, CanadaAbstract: Mesoporous surfaces generated by oxidative nanopatterning have the capacity to selectively regulate cell behavior, but their impact on microorganisms has not yet been explore...

Variola F; Sf, Zalzal; Leduc A; Barbeau J; Nanci A

2014-01-01

395

Controlling the Pore Size and Morphology of Mesoporous Silica  

OpenAIRE

Mesoporous silica with a hexagonally ordered pore structure (SBA-15) has been synthesized. Through variations in the synthesis conditions several morphologies, such as fibers, sheets and separate rods, have been realized. Furthermore, additions of heptane and NH4F make it possible to synthesize SBA-15 with pores as large as 18 nm in the sheet morphology. Mechanisms for the formation of different morphologies have been suggested. In the case of fibers and sheets, the amount of heptane present ...

Johansson, Emma M.

2010-01-01

396

Carbon black directed synthesis of ultrahigh mesoporous carbon aerogels  

OpenAIRE

[EN] A simple modification of the conventional sol–gel polymerization of resorcinol–formaldehyde mixtures allowed a facile preparation of ultrahigh mesoporous carbon gels. In the conventional synthesis the growth of the cluster polymer particles leading to the development of the porosity is controlled by the R/C ratio. In the presence of a carbon conductive additive, the polymerization of the reactants proceeded through the formation of less-branched polymer clusters resulting in carbon g...

Maci?as, Carlos; Haro Remo?n, Marta; Rasines, Gloria; Parra Soto, Jose? Bernardo; Ovi?n Ania, Mari?a Concepcio?n

2013-01-01

397

Functionalized mesoporous silica materials for molsidomine adsorption: Thermodynamic study  

International Nuclear Information System (INIS)

A series of unmodified and organically modified mesoporous silica materials was prepared. The unmodified mesoporous silica was synthesized via sol–gel synthesis in the presence of D-glucose as pore-forming agent. The functionalized by phenyl, aminopropyl and mercaptopropyl groups silica materials were prepared via grafting. The fabricated adsorbent materials were characterized by Fourier transform infrared spectroscopy (FTIR) analysis, N2 adsorption/desorption and elemental analysis methods. Then their adsorption properties for mesoionic dug molsidomine were investigated at 290–313 K and physiological pH value. Thermodynamic parameters of molsidomine adsorption on the synthesized materials have been calculated. The obtained results showed that the adsorption process of molsidomine on the phenyl modified silica is the most quantitatively and energetically favorable. The unmodified and mercaptopropyl modified silica materials exhibit significantly higher adsorption capacities and energies for molsidomine than the aminopropyl modified sample. The effects are discussed from the viewpoint of nature of specific interactions responsible for the adsorption. - Graphical abstract: Comparative analysis of the thermodynamic characteristics of molsidomine adsorption showed that the adsorption process on mesoporous silica materials is controlled by chemical nature of surface functional groups. Molsidomine adsorption on the phenyl modified silica is the most quantitatively and energetically favorable. Taking into account ambiguous nature of mesoionic compounds, it was found that molsidomine is rather aromatic than dipolar. Display Omitted - Highlights: • Unmodified and organically modified mesoporous silica materials were prepared. • Molsidomine adsorption on the silica materials was studied. • Phenyl modified silica shows the highest adsorption capacity and favorable energy. • Molsidomine exhibits the lowest affinity to aminopropyl modified silica

398

Sustained release of fungicide metalaxyl by mesoporous silica nanospheres  

International Nuclear Information System (INIS)

The use of nanomaterials for the controlled delivery of pesticides is nascent technology that has the potential to increase the efficiency of food production and decrease pollution. In this work, the prospect of mesoporous silica nanoparticles (MSN) for storage and controlled release of metalaxyl fungicide has been investigated. Mesoporous silica nanospheres with average particle diameters of 162 nm and average pore sizes of 3.2 nm were prepared by a sol–gel process. Metalaxyl molecules were loaded into MSN pores from an aqueous solution by a rotary evaporation method. The loaded amount of metalaxyl as evaluated by thermogravimetric analysis was about 14 wt%. Release of the fungicide entrapped in the MSN matrix revealed sustained release behavior. About 76 % of the free metalaxyl was released in soil within a period of 30 days while only 11.5 and 47 % of the metalaxyl contained in the MSN carrier was released in soil and water, respectively, within the same period. The study showed that MSN can be used to successfully store metalaxyl molecules in its mesoporous framework and significantly delay their release in soil

399

Cumene cracking on modified mesoporous material type MCM-41  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of ionic exchange degree of aluminated mesoporous materials H(X-AlMCM-41 materials, the method of its exchange mode and its grains form were investigated for the mesoporous catalytic activity in the cumene (i.e. isopropylbenzene cracking reaction. Benzene, propylene and xylene derivatives are the main products of this reaction. Olefins like butene and pentene appeared as the products of secondary reactions. No saturated hydrocarbons, except traces of butane, nor ethylbenzene and toluene were formed and seemed to be typical products of secondary reactions obtained with HNaY zeolites. Generally the exchanged H(X-AlMCM-41 materials by the substitution of Na+ by NH4+ are more active than those exchanged directly with acid solution (substitution of Na+ by H+ even if both the two methods used exhibit a comparable content of acid sites within catalysts at a low exchange degrees. However, the first method of exchange has exhibited an important acidity for mesoporous materials when the ionic exchange degree was increased up to 90%; it was probably due not only to the percentage of exchanged degree but also to the distribution of acid sites within the materials.

Ahmed Belhakem

2006-06-01

400

Ordered mesoporous carbon for electrochemical sensing: A review  

International Nuclear Information System (INIS)

Highlights: ? The preparation and functionalization of ordered mesoporous carbon. ? Their applications as electrochemical sensors with high electrocatalytic activity. ? A promising electrode material based on its interesting properties. - Abstract: With its well-ordered pore structure, high specific surface area and tunable pore diameters in the mesopore range, ordered mesoporous carbon (OMC) is suitable for applications in catalysis and sensing. We report recent applications of OMC in electrochemical sensors and biosensors. After a brief description of the electrochemical properties, the functionalization of the OMC for improvement of the electrocatalytic properties is then presented. We show how the ordered mesostructure of OMC is very important in those applications. The high density of edge plane-like defective sites (EDSs), oxygen-containing groups and a large surface area on OMC may provide many favorable sites for electron transfer to compounds, which makes OMC a potential novel material for an investigation of the electrochemical behavior of substances. Moreover, the structural capabilities of OMC at the scale of a few nanometers agree with immobilization of other electrocataytic substances. Interesting properties of this material may open up a new approach to study the electrochemical determination of other biomolecules.

401

Conductivity of liquid lithium electrolytes with dispersed mesoporous silica particles  

International Nuclear Information System (INIS)

Highlights: ? The conductivity of disperse lithium electrolytes with mesoporous fillers is studied. ? In contrast to other investigations in literature, no conductivity enhancement could be observed for standard battery electrolytes and typical mesoporous fillers in various combinations. ? Disperse electrolytes can become relevant in terms of battery safety. ? Dispersions of silicas and electrolyte with LiPF6 as conducting salt are not stable, although the silicas were dried prior to preparation and the electrolyte water content was controlled. Surface modification of the fillers improved the stability. ? The observed conductivity decrease varied considerably for various fillers. - Abstract: The electrical conductivity of disperse electrolytes was systematically measured as a function of temperature (0 °C to 60 °C) and filler content for different types of fillers with a range of pore geometry, pore structure and specific surface area. As fillers mesoporous silicas SBA-15, MCM-41 and KIT-6 with pore ranges between 3 nm and 15 nm were dispersed in commercially available liquid lithium electrolytes. As electrolytes 1 M of lithium hexafluorophosphate (LiPF6) in a mixture of ethylene carbonate (EC) and diethylene carbonate (DEC) at the ratio 3:7 (wt/wt) and the same solvent mixture with 0.96 M lithium bis(trifluoromethanesulfon)imide (LiTFSI) were used. No conductivity enhancement could be observed, but with respect to safety aspects the respect to safety aspects the highly viscous disperse pastes might be useful. The conductivity decrease varied considerably for the different fillers.

402

Functionalized mesoporous silica nanoparticles for oral delivery of budesonide  

Energy Technology Data Exchange (ETDEWEB)

Non-functionalized and amino-functionalized mesoporous silica nanoparticle were loaded with anti-inflammatory drug budesonide and additionally post-coated with bioadhesive polymer (carbopol). TEM images showed spherical shape of the nanoparticles and slightly higher polydispersity after coating with carbopol. Nitrogen physisorption and thermogravimetic analysis revealed that more efficient loading and incorporation into the pores of nanoparticles was achieved with the amino-functionalized silica carrier. Infrared spectra indicated that the post-coating of these nanoparticles with carbopol led to the formation of bond between amino groups of the functionalized carrier and carboxyl groups of carbopol. The combination of amino-functionalization of the carrier with the post-coating of the nanoparticles sustained budesonide release. Further, an in vitro model of inflammatory bowel disease showed that the cytoprotective effect of budesonide loaded in the post-coated silica nanoparticles on damaged HT-29 cells was more pronounced compared to the cytoprotection obtained with pure budesonide. -- Graphical abstract: Silica mesoporous MCM-41 particles were amino-functionalized, loaded with budesonide and post-coated with bioadhesive polymer (carbopol) in order to achieve prolonged residence of anti-inflammatory drug in GIT. Highlights: • Higher drug loading in amino-functionalized mesoporous silica. • Amino-functionalization and post-coating of the nanoparticles sustained drug release. • Achievement of higher cytoprotective effect with drug loaded into the nanoparticles.

Yoncheva, K., E-mail: krassi.yoncheva@gmail.com [Department of Pharmaceutical Technology, Faculty of Pharmacy, Medical University of Sofia, 2 Dunav Str., 1000 Sofia (Bulgaria); Popova, M. [Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia (Bulgaria); Szegedi, A.; Mihaly, J. [Institute of Nanochemistry and Catalysis, Chemical Research Center, Hungarian Academy of Sciences, Pusztaszeri út. 59-67, 1025 Budapest (Hungary); Tzankov, B.; Lambov, N.; Konstantinov, S.; Tzankova, V. [Department of Pharmaceutical Technology, Faculty of Pharmacy, Medical University of Sofia, 2 Dunav Str., 1000 Sofia (Bulgaria); Pessina, F.; Valoti, M. [Dipartimento di Scienze della Vita, Universita di Siena, via Aldo Moro 2, Siena (Italy)

2014-03-15

403

Functionalized mesoporous silica nanoparticles for oral delivery of budesonide  

International Nuclear Information System (INIS)

Non-functionalized and amino-functionalized mesoporous silica nanoparticle were loaded with anti-inflammatory drug budesonide and additionally post-coated with bioadhesive polymer (carbopol). TEM images showed spherical shape of the nanoparticles and slightly higher polydispersity after coating with carbopol. Nitrogen physisorption and thermogravimetic analysis revealed that more efficient loading and incorporation into the pores of nanoparticles was achieved with the amino-functionalized silica carrier. Infrared spectra indicated that the post-coating of these nanoparticles with carbopol led to the formation of bond between amino groups of the functionalized carrier and carboxyl groups of carbopol. The combination of amino-functionalization of the carrier with the post-coating of the nanoparticles sustained budesonide release. Further, an in vitro model of inflammatory bowel disease showed that the cytoprotective effect of budesonide loaded in the post-coated silica nanoparticles on damaged HT-29 cells was more pronounced compared to the cytoprotection obtained with pure budesonide. -- Graphical abstract: Silica mesoporous MCM-41 particles were amino-functionalized, loaded with budesonide and post-coated with bioadhesive polymer (carbopol) in order to achieve prolonged residence of anti-inflammatory drug in GIT. Highlights: • Higher drug loading in amino-functionalized mesoporous silica. • Amino-functionalization and post-coating of the nanoparticles sustained drug release. • Achievement of higher cytoprotective effect with drug loaded into the nanoparticles

404

Soft-Template-Synthesized Mesoporous Carbon for Oral Drug Delivery  

Energy Technology Data Exchange (ETDEWEB)

Template-synthesized mesoporous carbons were successfully used in in vitro investigations of controlled delivery of three model drugs, captopril, furosemide, and ranitidine hydrochloride. Captopril and furosemide exhibited desorption kinetics over 30 40 h, and ranitidine HCl had a complete release time of 5 10 h. As evident from the slow release kinetics, we contend that our mesoporous carbon is an improved drug-delivery medium compared to state-of-the-art porous silica-based substrates. The mesoporous carbons, synthesized from phloroglucinol and lignin, a synthetic and a sustainable precursor, respectively, exhibit BET surface area of 200 400 m2 g-1 and pore volume of 0.2 0.6 cm3 g-1. The phloroglucinol-based carbon has narrower pore widths and higher pore volume than the lignin-derived counterpart and maintains a longer release time. Numerical modeling of the release kinetics data reveals that the diffusivities of all the drugs from lignin-based carbon media are of equivalent magnitude (10-22 to 10-24 m2 s-1). However, a tailored reduction of pore width in the sorbent reduces the diffusivity of smaller drug molecules (captopril) by an order of magnitude. Thus, engineered pore morphology in our synthesized carbon sorbent, along with its potential to tailor the chemistry of its interaction with sorbet, can be exploited for optimal delivery system of a preferred drug within its therapeutic level and below the level of toxicity.

Saha, Dipendu [ORNL; Warren, Kaitlyn E [ORNL; Naskar, Amit K [ORNL

2014-01-01

405

Sonochemical fabrication of fluorinated mesoporous titanium dioxide microspheres  

International Nuclear Information System (INIS)

A sonochemical-hydrothermal method for preparing fluorinated mesoporous TiO2 microspheres was developed. Formation of mesoporous TiO2 and doping of fluorine was achieved by sonication and then hydrothermal treatment of a solution containing titanium isopropoxide, template, and sodium fluoride. The as-synthesized TiO2 microspheres were characterized by X-ray diffraction (XRD), Fourier translation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) spectroscopy, photoluminescence spectroscopy (PL), and BET surface areas. The P123 template was removed completely during the hydrothermal and washing steps, which was different from the conventional calcination treatment. The as- synthesized TiO2 microspheres had good crystallinity and high stability. Results from the photocatalytic degradation of methylene blue (MB) showed that fluorination could remarkably improve the photocatalytic activity of titanium dioxide. - Graphical abstract: A novel method for preparing fluorinated mesoporous TiO2 microspheres was developed by a combined ultrasonic and hydrothermal treatment. The fluorinated TiO2 microspheres show high crystallinity, stability and enhanced photocatalytic activity.

406

N-doped mesoporous alumina for adsorption of carbon dioxide.  

Science.gov (United States)

N-doped mesoporous alumina has been synthesized using chitosan as the biopolymer template. The adsorbent has been thoroughly investigated for the adsorption of CO2 from a simulated flue gas stream (15% CO2 balanced with N2) and compared with commercially available mesoporous alumina procured from SASOL, Germany. CO2 adsorption was studied under different conditions of pretreatment and adsorption temperature, inlet CO2 concentration and in the presence of oxygen and moisture. The adsorption capacity was determined to be 29.4 mg CO2/g of adsorbent at 55 degrees C. This value was observed to be 4 times higher in comparison to that of commercial mesoporous alumina at a temperature of 55 degrees C. Basicity of alumina surface coupled with the presence of nitrogen in template in synthesized sample is responsible for this enhanced CO2 adsorption. Adsorption capacity for CO2 was retained in the presence of oxygen; however moisture had a deteriorating effect on the adsorption capacity reducing it to nearly half the value. PMID:23534232

Thote, Jayshri A; Chatti, Ravikrishna V; Iyer, Kartik S; Kumar, Vivek; Valechha, Arti N; Labhsetwar, Nitin K; Biniwale, Rajesh B; Yenkie, M K N; Rayalu, Sadhana S

2012-01-01

407

Capacity of mesoporous bioactive glass nanoparticles to deliver therapeutic molecules  

Science.gov (United States)

Inorganic bioactive nanomaterials are attractive for hard tissue regeneration, including nanocomponents for bone replacement composites and nanovehicles for delivering therapeutics. Bioactive glass nanoparticles (BGn) have recently gained potential usefulness as bone and tooth regeneratives. Here we demonstrate the capacity of the BGn with mesopores to load and deliver therapeutic molecules (drugs and particularly genes). Spherical BGn with sizes of 80-90 nm were produced to obtain 3-5 nm sized mesopores through a sono-reacted sol-gel process. A simulated body fluid test of the mesoporous BGn confirmed their excellent apatite forming ability and the cellular toxicity study demonstrated their good cell viability up to 100 ?g ml-1. Small molecules like chemical drug (Na-ampicillin) and gene (small interfering RNA; siRNA) were introduced as model drugs considering the mesopore size of the nanoparticles. Moreover, amine-functionalization allowed switchable surface charge property of the BGn (from -20-30 mV to +20-30 mV). Loading of ampicillin or siRNA saturated within a few hours (~2 h) and reflected the mesopore structure. While the ampicillin released relatively rapidly (~12 h), the siRNA continued to release up to 3 days with almost zero-order kinetics. The siRNA-nanoparticles were easily taken up by the cells, with a transfection efficiency as high as ~80%. The silencing effect of siRNA delivered from the BGn, as examined by using bcl-2 model gene, showed dramatic down-regulation (~15% of control), suggesting the potential use of BGn as a new class of nanovehicles for genes. This, in conjunction with other attractive properties, including size- and mesopore-related high surface area and pore volume, tunable surface chemistry, apatite-forming ability, good cell viability and the possible ion-related stimulatory effects, will potentiate the usefulness of the BGn in hard tissue regeneration.Inorganic bioactive nanomaterials are attractive for hard tissue regeneration, including nanocomponents for bone replacement composites and nanovehicles for delivering therapeutics. Bioactive glass nanoparticles (BGn) have recently gained potential usefulness as bone and tooth regeneratives. Here we demonstrate the capacity of the BGn with mesopores to load and deliver therapeutic molecules (drugs and particularly genes). Spherical BGn with sizes of 80-90 nm were produced to obtain 3-5 nm sized mesopores through a sono-reacted sol-gel process. A simulated body fluid test of the mesoporous BGn confirmed their excellent apatite forming ability and the cellular toxicity study demonstrated their good cell viability up to 100 ?g ml-1. Small molecules like chemical drug (Na-ampicillin) and gene (small interfering RNA; siRNA) were introduced as model drugs considering the mesopore size of the nanoparticles. Moreover, amine-functionalization allowed switchable surface charge property of the BGn (from -20-30 mV to +20-30 mV). Loading of ampicillin or siRNA saturated within a few hours (~2 h) and reflected the mesopore structure. While the ampicillin released relatively rapidly (~12 h), the siRNA continued to release up to 3 days with almost zero-order kinetics. The siRNA-nanoparticles were easily taken up by the cells, with a transfection efficiency as high as ~80%. The silencing effect of siRNA delivered from the BGn, as examined by using bcl-2 model gene, showed dramatic down-regulation (~15% of control), suggesting the potential use of BGn as a new class of nanovehicles for genes. This, in conjunction with other attractive properties, including size- and mesopore-related high surface area and pore volume, tunable surface chemistry, apatite-forming ability, good cell viability and the possible ion-related stimulatory effects, will potentiate the usefulness of the BGn in hard tissue regeneration. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr31775c

El-Fiqi, Ahmed; Kim, Tae-Hyun; Kim, Meeju; Eltohamy, Mohamed; Won, Jong-Eun; Lee, Eun-Jung; Kim, Hae-Won

2012-11-01

408

A Review: Fundamental Aspects of Silicate Mesoporous Materials  

Directory of Open Access Journals (Sweden)

Full Text Available Silicate mesoporous materials have received widespread interest because of their potential applications as supports for catalysis, separation, selective adsorption, novel functional materials, and use as hosts to confine guest molecules, due to their extremely high surface areas combined with large and uniform pore sizes. Over time a constant demand has developed for larger pores with well-defined pore structures. Silicate materials, with well-defined pore sizes of about 2.0–10.0 nm, surpass the pore-size constraint (<2.0 nm of microporous zeolites. They also possess extremely high surface areas (>700 m2 g?1 and narrow pore size distributions. Instead of using small organic molecules as templating compounds, as in the case of zeolites, long chain surfactant molecules were employed as the structure-directing agent during the synthesis of these highly ordered materials. The structure, composition, and pore size of these materials can be tailored during synthesis by variation of the reactant stoichiometry, the nature of the surfactant molecule, the auxiliary chemicals, the reaction conditions, or by post-synthesis functionalization techniques. This review focuses mainly on a concise overview of silicate mesoporous materials together with their applications. Perusal of the review will enable researchers to obtain succinct information about microporous and mesoporous materials.

Zeid A. ALOthman

2012-12-01

409

Carbon dioxide capture using polyethylenimine-loaded mesoporous carbons.  

Science.gov (United States)

A high efficiency sorbent for CO2 capture was developed by loading polyethylenimine (PEI) on mesoporous carbons which possessed well-developed mesoporous structures and large pore volume. The physicochemical properties of the sorbent were characterized by N2 adsorption/desorption, scanning electron microscopy (SEM), thermal gravimetric analysis (TG) and Fourier transform infrared spectroscopy (FT-IR) techniques followed by testing for CO2 capture. Factors that affected the sorption capacity of the sorbent were studied. The sorbent exhibited extraordinary capture capacity with CO2 concentration ranging from 5% to 80%. The optimal PEI loading was determined to be 65 wt.% with a CO2 sorption capacity of 4.82 mmol-CO2/g-sorbent in 15% CO2/N2 at 75 degrees C, owing to low mass-transfer resistance and a high utilization ratio of the amine compound (63%). Moisture had a promoting effect on the sorption separation of CO2. In addition, the developed sorbent could be regenerated easily at 100 degrees C, and it exhibited excellent regenerability and stability. These results indicate that this PEI-loaded mesoporous carbon sorbent should have a good potential for CO2 capture in the future. PMID:23586307

Wang, Jitong; Chen, Huichao; Zhou, Huanhuan; Liu, Xiaojun; Qiao, Wenming; Long, Donghui; Ling, Licheng

2013-01-01

410

IR-spectrophotoelectrochemical characterization of mesoporous semiconductor films.  

Science.gov (United States)

A combined IR-spectroscopic and electrochemical approach for the study of photo- and bias-induced reactions at the semiconductor/electrolyte interface is presented. Information on the electronic structure of a mesoporous semiconductor nanoparticle network, concretely the density and distribution of band gap states, as well as the nature of solution species are analyzed in situ. It has been shown that under appropriate conditions the electrode potential determines the quasi-Fermi level throughout the mesoporous film and thus the occupation of IR-active band gap states, independently of the type of external perturbation, i.e., application of a bias voltage or electrode exposure to photons exceeding the semiconductor band gap at open circuit. Importantly, electronic properties of the semiconductor and vibrational properties of solution species can be addressed simultaneously by IR-spectroscopy. In addition, electrochemical methods provide a means for the active manipulation (in potentiostatic measurements) or the passive tracking (during open circuit potential decay) of the quasi-Fermi level in the mesoporous film together with the possibility of electron quantification (by charge extraction experiments). PMID:22413918

Berger, Thomas; Anta, Juan A

2012-04-01

411

Effect of polysulfonate resins and direct compression fillers on multiple-unit sustained-release dextromethorphan resinate tablets  

OpenAIRE

The purpose of this work was to investigate the effect of different polysulfonate resins and direct compression fillers on physical properties of multiple-unit sustained-release dextromethorphan (DMP) tablets. DMP resinates were formed by a complexation of DMP and strong cation exchange resins, Dowex 50 W and Amberlite IRP69. The tablets consisted of the DMP resinates and direct compression fillers, such as microcrystalline cellulose (MCC), dicalcium phosphate dihydrate (DCP), and spray-dried...

Pongjanyakul, Thaned; Priprem, Aroonsri; Chitropas, Padungkwan; Puttipipatkhachorn, Satit

2005-01-01

412

Low-melt Viscosity Polyimide Resins for Resin Transfer Molding (RTM) II  

Science.gov (United States)

A series of polyimide resins with low-melt viscosities in the range of 10-30 poise and high glass transition temperatures (Tg s) of 330-370 C were developed for resin transfer molding (RTM) applications. These polyimide resins were formulated from 2,3,3 ,4 -biphenyltetracarboxylic dianhydride (a-BPDA) with 4-phenylethynylphthalic anhydride endcaps along with either 3,4 - oxyaniline (3,4 -ODA), 3,4 -methylenedianiline, (3,4 -MDA) or 3,3 -methylenedianiline (3,3 -MDA). These polyimides had pot lives of 30-60 minutes at 260-280 C, enabling the successful fabrication of T650-35 carbon fiber reinforced composites via RTM process. The viscosity profiles of the polyimide resins and the mechanical properties of the polyimide carbon fiber composites will be discussed.

Chuang, Kathy C.; Criss, Jim M.; Mintz, Eric A.; Scheiman, Daniel A.; Nguyen, Baochau N.; McCorkle, Linda S.

2007-01-01

413

Effect of epoxy resin properties on the mechanical properties of carbon fiber/epoxy resin composites  

Energy Technology Data Exchange (ETDEWEB)

Three kinds of epoxy resins, i.e. tetraglycidyl diaminodiphenyl methane (AG80), difunctional diglycidyl ether of bisphenol-A (E51) and novolac type epoxy resin (F46) were selected as matrices for carbon fiber/epoxy composites. The objective of this work is to study the mechanical properties of fiber/epoxy composites by using these three kinds of epoxy resins with different physical and chemical performance. The results show that the composites fabricated with AG80 present the best stiffness and the composites prepared with E5 1have the best toughness. The stiffness and toughness of the composites prepared with F46 are middle values located between those for AG80/epoxy and E51/epoxy composites. Thus, the mixed epoxy resin is a promising approach for industrial production. (orig.)

He, Hong-Wei; Gao, Feng [Taiyuan Univ. of Technology (China). College of Materials Science and Engineering; Taiyuan Univ. of Technology (China). Key Laboratory of Interface Science and Engineering in Advanced Materials; Li, Kai-Xi [Chinese Academy of Sciences, Taiyuan, Shanxi (China). Key Laboratory of Carbon Materials

2013-09-15

414

Synthesis and characterization of resorcinol–formaldehyde resin chars doped by zinc oxide  

Energy Technology Data Exchange (ETDEWEB)

Polycondensation polymerization of resorcinol–formaldehyde (RF) mixtures in water with addition of different amounts of zinc acetate and then carbonization of dried gels are studied to prepare ZnO doped chars. Zinc acetate as a catalyst of resorcinol–formaldehyde polycondensation affects structural features of the RF resin (RFR) and, therefore, the texture of chars prepared from Zn-doped RFR. The ZnO doped chars are characterized using thermogravimetry, low temperature nitrogen adsorption/desorption, Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HRTEM). At a relatively high content of zinc acetate (1 mol per 10–40 mol of resorcinol) in the reaction mixture, the formation of crystallites of ZnO (zincite) occurs in a shape of straight nanorods of 20–130 nm in diameter and 1–3 ?m in length. At a small content of zinc acetate (1 mol per 100–500 mol of resorcinol), ZnO in composites is XRD amorphous and does not form individual particles. The ZnO doped chars are pure nanoporous at a minimal ZnO content and nano-mesoporous or nano-meso-macroporous at a higher ZnO content.

Gun’ko, Vladimir M., E-mail: vlad_gunko@ukr.net [Chuiko Institute of Surface Chemistry, 17 General Naumov Street, 03164 Kyiv (Ukraine); Bogatyrov, Viktor M.; Oranska, Olena I. [Chuiko Institute of Surface Chemistry, 17 General Naumov Street, 03164 Kyiv (Ukraine); Urubkov, Iliya V. [Kurdyumov Institute of Metal Physics, 36 Vernadsky Boulevard, 03142 Kyiv (Ukraine); Leboda, Roman; Charmas, Barbara; Skubiszewska-Zi?ba, Jadwiga [Faculty of Chemistry, Maria Curie-Sk?odowska University, 20031 Lublin (Poland)

2014-06-01

415

Synthesis and characterization of resorcinol-formaldehyde resin chars doped by zinc oxide  

Science.gov (United States)

Polycondensation polymerization of resorcinol-formaldehyde (RF) mixtures in water with addition of different amounts of zinc acetate and then carbonization of dried gels are studied to prepare ZnO doped chars. Zinc acetate as a catalyst of resorcinol-formaldehyde polycondensation affects structural features of the RF resin (RFR) and, therefore, the texture of chars prepared from Zn-doped RFR. The ZnO doped chars are characterized using thermogravimetry, low temperature nitrogen adsorption/desorption, Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HRTEM). At a relatively high content of zinc acetate (1 mol per 10-40 mol of resorcinol) in the reaction mixture, the formation of crystallites of ZnO (zincite) occurs in a shape of straight nanorods of 20-130 nm in diameter and 1-3 ?m in length. At a small content of zinc acetate (1 mol per 100-500 mol of resorcinol), ZnO in composites is XRD amorphous and does not form individual particles. The ZnO doped chars are pure nanoporous at a minimal ZnO content and nano-mesoporous or nano-meso-macroporous at a higher ZnO content.

Gun'ko, Vladimir M.; Bogatyrov, Viktor M.; Oranska, Olena I.; Urubkov, Iliya V.; Leboda, Roman; Charmas, Barbara; Skubiszewska-Zi?ba, Jadwiga

2014-06-01

416

Microbial treatment of ion exchange resins  

Energy Technology Data Exchange (ETDEWEB)

A bioavailability of ion exchange resins to a microbial destruction as one of the alternative methods of compacting used ionites from the nuclear fuel manufacturing cycle enterprises has been investigated. The bio-destruction was studied after a preliminary chemical treatment or without it. A sensitivity of the ion exchange resins (including highly acidic cationite KU-2-8) to the microbial destruction by heterotrophic and chemo-litho-trophic microorganisms under aerobic conditions was shown in principle. The biodegradation of the original polymer is possible in the presence of the water soluble fraction of the resin obtained after its treatment by Fenton reagent and accelerated in the presence of Mn-ions in optimal concentration 1-2 g of Mn per liter of medium. Thus, the process of bio-destruction of ionite polymer by heterotrophic microorganisms can be compared with the bio-destruction of lignin or humic substances. The optimum parameters of bio-destruction and microorganisms used must be different for resins with different functional groups. (authors)

Kouznetsov, A.; Kniazev, O. [D. Mendeleyev University of Chemical Technology of Russia, Dept. Biotechnology, Mocow (Russian Federation)

2001-07-01

417

Resin diffusion through demineralized dentin matrix  

OpenAIRE

This paper has focused on the factors that may affect the permeability of adhesive resins into the demineralized dentin matrix during the development of the bonding process. The effects of surface moisture are discussed respectively to the adhesive systems, and the problems related to incomplete hybrid layer formation presented.

Carvalho, Ricardo M.; Ciucchi, Bernard; Sano, Hidehiko; Yoshiyama, Masahiro; Pashley, David H.

1999-01-01

418

Resin diffusion through demineralized dentin matrix  

Directory of Open Access Journals (Sweden)

Full Text Available This paper has focused on the factors that may affect the permeability of adhesive resins into the demineralized dentin matrix during the development of the bonding process. The effects of surface moisture are discussed respectively to the adhesive systems, and the problems related to incomplete hybrid layer formation presented.

CARVALHO Ricardo M.

1999-01-01

419

Microbial treatment of ion exchange resins  

International Nuclear Information System (INIS)

A bioavailability of ion exchange resins to a microbial destruction as one of the alternative methods of compacting used ionites from the nuclear fuel manufacturing cycle enterprises has been investigated. The bio-destruction was studied after a preliminary chemical treatment or without it. A sensitivity of the ion exchange resins (including highly acidic cationite KU-2-8) to the microbial destruction by heterotrophic and chemo-litho-trophic microorganisms under aerobic conditions was shown in principle. The biodegradation of the original polymer is possible in the presence of the water soluble fraction of the resin obtained after its treatment by Fenton reagent and accelerated in the presence of Mn-ions in optimal concentration 1-2 g of Mn per liter of medium. Thus, the process of bio-destruction of ionite polymer by heterotrophic microorganisms can be compared with the bio-destruction of lignin or humic substances. The optimum parameters of bio-destruction and microorganisms used must be different for resins with different functional groups. (authors)

420

Epoxy resins produce improved plastic scintillators  

Science.gov (United States)

Plastic scintillator produced by the substitution of epoxy resins for the commonly used polystyrene is easy to cast, stable at room temperature, and has the desirable properties of a thermoset or cross-linked system. Such scintillators can be immersed directly in strong solvents, an advantage in many chemical and biological experiments.

Markley, F. W.

1967-01-01

421

Nanostructured polymers based on epoxy resins.  

Czech Academy of Sciences Publication Activity Database

Praha : Ústav makromolekulární chemie AV ?R, 2010. L_16. ISBN 978-80-85009-62-0. [Workshop "Career in Polymers" /2./. 23.07.2010-24.07.2010, Praha] R&D Projects: GA AV ?R IAA400500701 Institutional research plan: CEZ:AV0Z40500505 Keywords : nanostructured polymers * epoxy resins * nanocomposite properties Subject RIV: CD - Macromolecular Chemistry

Kubiszyn, Malgorzata; Pleštil, Josef; Mat?jka, Libor

422

Evaluation of resins for use in brachytherapy  

Energy Technology Data Exchange (ETDEWEB)

Brachytherapy is an advanced cancer treatment where radioactive seeds or sources are placed near or directly into the tumor thus reducing the radiation exposure in the surrounding healthy tissues. Prostate cancer can be treated with interstitial brachytherapy in initial stage of the disease in which tiny radioactive seeds with cylindrical geometry are used. Several kinds of seeds have been developed in order to obtain a better dose distribution around them and with a lower cost manufacturing. These seeds consist of an encapsulation, a radionuclide carrier, and X-ray marker. Among the materials that have potential for innovation in the construction of seeds, biocompatible resins appear as an important option. In this paper, we present some characterization results with Fourier transform infrared spectroscopic (FTIR) and ultraviolet-visible spectroscopy (UV-vis) performed on two types of resins in which curing temperatures for each one were varied as also the results of coatings with these resins under titanium substrates. Interactions of these resins in contact with the simulated body fluid were evaluated by atomic force microscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy. (author)

Carvalho, Luiz Claudio F.M. Garcia; Ferraz, Wilmar Barbosa; Chrcanovic, Bruno Ramos; Santos, Ana Maria M., E-mail: ferrazw@cdtn.b, E-mail: amms@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2011-07-01

423

Triterpenes from the resin of Boswellia neglecta  

Directory of Open Access Journals (Sweden)

Full Text Available The resin of Boswellia neglecta yielded four triterpenes canaric acid, ?-amyrin, ?-amyrone and epi-?-amyrin. Canaric acid and epi-?-amyrin are isolated here for the first time from the family Burseraceae. The compounds were identified using 1D and 2D NMR techniques.

Aman Dekebo

2002-06-01

424

Vapour absorption in melamine-formaldehyde resin  

International Nuclear Information System (INIS)

The effects of vapour absorption on positron annihilation in cross-linked polymer were investigated. Contrary to linear polymers, absorption of vapor in cross-linked resin leads to the shortening of o-Ps lifetime. In vacuum absorbed molecules diffuse out. At room temperature desorption of hexane and hexanol is not complete; full elimination of absorbed molecules requires sample temperature increase. (author)

425

[Modification of resin using reactive polymeric nanoparticles].  

Science.gov (United States)

Volumetric shrinkage during polymerization has always caused problems since polymer based composites are used as dental filling materials. This value has been reduced to 2-4 volume % with the improvement of dental filling materials and of suitable filling technique. The purpose of our study was to synthesize reactive polymeric nanoparticles which can be applied to modify the polymerization shrinkage of dental resin. It means that certain part of a commercial dental resin would be substituted with reactive polymeric nanoparticles as organic filler. According to our hypothesis the volume contraction would significantly be reduced by applying the modified resin with organic filler. Nanoparticles were prepared by free radical copolymerization from mono-, di- and trifunctional monomers in emulsion and organic solution. In emulsion their size distribution is narrow, but it is quite variable in solutions. The size, size distribution and reactivity of nanoparticles were examined, and these properties can be influenced by the mol ratio and concentration of the monomers. It was shown that the nanoparticles could be swollen by the matrix material and these build a unique structure that can be photo-polymerized. During polymerization the shrinkage of the copolymer can be considered zero, consequently the total contraction originates from the shrinkage of the matrix. In the modified resin the reactive groups of monomers and the pendant double bounds of nanoparticles were connected by covalent bond. PMID:18361204

Szalóki, Melinda; Bukovinszki, Katalin; Uveges, Andrea; Hegedus, Csaba; Borbély, János

2007-12-01

426

21 CFR 177.1595 - Polyetherimide resin.  

Science.gov (United States)

...Components of Single and Repeated Use Food Contact Surfaces § 177.1595 Polyetherimide...an article intended for use in contact with food, subject to the provisions of...production of basic resins or finished food-contact articles. The optional...

2010-04-01

427

Mesoporous zeolite single crystal catalysts: Diffusion and catalysis in hierarchical zeolites  

DEFF Research Database (Denmark)

During the last years, several new routes to produce zeolites with controlled mesoporosity have appeared. Moreover, an improved catalytic performance of the resulting mesoporous zeolites over conventional zeolites has been demonstrated in several reactions. In most cases, the mesoporous zeolites exhibit higher catalytic activity, but in some cases also improved selectivity and longer catalyst lifetime has been reported. The beneficial effects of introducing mesopores into the zeolites has in most instances been attributed to improved mass transport to and from the active sites located in the zeolite micropores. Here, we briefly discuss the most important ways of introducing mesopores into zeolites and, for the first time, we show experimentally that the presence of mesopores dramatically increases the rate of diffusion in zeolite catalysts. This is done by studying the elution of iso-butane from packed beds of conventional and mesoporous zeolite catalysts. Moreover, we discuss in detail the recent observationof improved activity and selectivity in the alkylation of benzene with ethene using mesoporous zeolite single crystal catalysts. For this reaction, we show by calculation of the Thiele modulus that this improved performance can be mainly attributed to a diffusional limitation of ethylbenzene in the zeolite pores. This is verified in new ethylbenzene dealkylation experiments where mesoporous zeolite catalysts show significantly improved activity over conventional zeolite catalysts.

Christensen, Christina Hviid; Johannsen, Kim

2007-01-01

428

Hexagonal Mesoporous Silicas with and without Zr as Supports for HDS Catalysts.  

Czech Academy of Sciences Publication Activity Database

Ro?. 65, 2-4 (2001), s. 217-223. ISSN 0920-5861 Institutional research plan: CEZ:AV0Z4072921 Keywords : hydrodesulphurization * mesoporous materials * Zirconium-containing mesoporous silicas Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.333, year: 2001

Kostova, N. G.; Spojakina, A. A.; Jirátová, Kv?ta; Šolcová, Olga; Dimitrov, L. D.; Petrov, L. A.

2001-01-01

429

Synthesis of organic-inorganic hybrid mesoporous tin oxophosphate in the presence of anionic surfactant.  

Science.gov (United States)

Synthesis of novel mesoporous hybrid tin oxophosphate is reported from phenylphosphonic acid as the only precursor of phosphorus in the presence of anionic surfactant (SDS), which possesses a wormhole mesoporous structure and is stable even after calcination at 550 degrees C. PMID:16228034

Mal, Nawal Kishor; Fujiwara, Masahiro; Matsukata, Masahiko

2005-11-01

430

Surfactant-free synthesis of mesoporous and hollow silica nanoparticles with an inorganic template.  

Science.gov (United States)

A surfactant-free synthesis of mesoporous and hollow silica nanoparticles is reported in which boron acts as the templating agent. Using such a simple and mild procedure as a treatment with water, the boron-rich phase is selectively removed, affording mesoporous pure silica nanoparticles with wormhole-like pores or, depending on the synthetic conditions, silica nanoshells. PMID:20024287

Baù, Luca; Bártová, Barbora; Arduini, Maria; Mancin, Fabrizio

2009-12-28

431

Surfactant-free synthesis of mesoporous and hollow silica nanoparticles with an inorganic template  

OpenAIRE

A surfactant-free synthesis of mesoporous and hollow silica nanoparticles is reported in which boron acts as the templating agent. Using such a simple and mild procedure as a treatment with water, the boron-rich phase is selectively removed, affording mesoporous pure silica nanoparticles with wormhole-like pores or, depending on the synthetic conditions, silica nanoshells.

Bau, L.; Bartova, B.; Arduini, M.; Mancin, F.

2009-01-01

432

Rapid (templated ordered mesoporous metal oxide and carbonate films using nitrate-citric acid systems.  

Science.gov (United States)

Rapid chemical transformation from micelle templated precursors (metal nitrate and citric acid) to ordered mesoporous metal carbonates and oxides is demonstrated using microwave heating for cobalt, copper, manganese and zinc. Without aging requirements, <3 min of microwave processing yields highly ordered mesoporous films. PMID:25714045

Zhang, Yuanzhong; Bhaway, Sarang M; Wang, Yi; Cavicchi, Kevin A; Becker, Matthew L; Vogt, Bryan D

2015-03-10

433

A bio-catalytically driven Janus mesoporous silica cluster motor with magnetic guidance.  

Science.gov (United States)

A bio-catalytic Janus motor based on the mesoporous silica cluster (JMSC) is fabricated. Chemically conjugated catalase triggers the decomposition of H2O2 to produce driving force by bubble propulsion, while a metallic (Ni) coating layer allows for magnetic guidance of the motor. The JMSC motor can act as a delivery vehicle with cargo loading inside its mesopores. PMID:25407318

Ma, Xing; Sanchez, Samuel

2015-03-12

434

High-performance electrocatalysts for oxygen reduction derived from cobalt porphyrin-based conjugated mesoporous polymers.  

Science.gov (United States)

A cobalt-nitrogen-doped porous carbon that exhibits a ribbon-shape morphology, high surface area, mesoporous structure, and high nitrogen and cobalt content is fabricated for high-performance self-supported oxygen reduction electrocatalytsts through template-free pyrolysis of cobalt porphyrin-based conjugated mesoporous polymer frameworks. PMID:24293313

Wu, Zhong-Shuai; Chen, Long; Liu, Junzhi; Parvez, Khaled; Liang, Haiwei; Shu, Jie; Sachdev, Hermann; Graf, Robert; Feng, Xinliang; Müllen, Klaus

2014-03-01

435

Studies on Supercapacitor Electrode Material from Activated Lignin-Derived Mesoporous Carbon  

Energy Technology Data Exchange (ETDEWEB)

We synthesized mesoporous carbon from pre-cross-linked lignin gel impregnated with a surfactant as the pore-forming agent, and then activated the carbon through physical and chemical methods to obtain activated mesoporous carbon. The activated mesoporous carbons exhibited 1.5- to 6-fold increases in porosity with a maximum BET specific surface area of 1148 m2/g and a pore volume of 1.0 cm3/g. Slow physical activation helped retain dominant mesoporosity; however, aggressive chemical activation caused some loss of the mesopore volume fraction. Plots of cyclic voltammetric data with the capacitor electrode made from these carbons showed an almost rectangular curve depicting the behavior of ideal double-layer capacitance. Although the pristine mesoporous carbon exhibited the same range of surface-area-based capacitance as that of other known carbon-based supercapacitors, activation decreased the surface-area-based specific capacitance and increased the gravimetric-specific capacitance of the mesoporous carbons. Surface activation lowered bulk density and electrical conductivity. Warburg impedance as a vertical tail in the lower frequency domain of Nyquist plots supported good supercapacitor behavior for the activated mesoporous carbons. Our work demonstrated that biomass-derived mesoporous carbon materials continue to show potential for use in specific electrochemical applications.

Saha, Dipendu [ORNL; Li, Yunchao [ORNL; Bi, Zhonghe [ORNL; Chen, Jihua [ORNL; Keum, Jong Kahk [ORNL; Hensley, Dale K [ORNL; Grappe, Hippolyte A. [Oak Ridge Institute for Science and Education (ORISE); Meyer III, Harry M [ORNL; Dai, Sheng [ORNL; Paranthaman, Mariappan Parans [ORNL; Naskar, Amit K [ORNL

2014-01-01

436

Decomposition of Rare Earth Loaded Resin Particles  

International Nuclear Information System (INIS)

The Fuel Cycle R and D (FCR and D) program within the Department of Energy Office of Nuclear Energy (DOE-NE) is evaluating nuclear fuel cycle options, including once-through, modified open, and fully closed cycles. Each of these scenarios may utilize quite different fuel management schemes and variation in fuel types may include high thermal conductivity UO2, thoria-based, TRISO, metal, advanced ceramic (nitride, carbide, composite, etc.), and minor actinide (MA) bearing fuels and targets. Researchers from the US, Europe, and japan are investigating methods of fabricating high-specific activity spherical particles for fuel and target applications. The capital, operating, and maintenance costs of such a fuel fabrication facility can be significant, thus fuel synthesis and fabrication processes that minimize waste and process losses, and require less footprint are desired. Investigations have been performed at the Institute for Transuranium Elements (ITU) and the French Atomic Energy Commission (CEA) studying the impact of americium and curium on the fuel fabrication process. proof of concept was demonstrated for fabrication of MA-bearing spherical particles, however additional development will be needed for engineering scale-up. Researchers at the Paul Scherer Institute (PSI) and the Japan Atomic Energy Association (JAEA) have collaborated on research with ceramic-metallic (CERMET) fuels using spherical particles as the ceramic component dispersed in the metthe ceramic component dispersed in the metal matrix. Recent work at the CEA evaluates the burning of MA in the blanket region of sodium fast reactors. There is also interest in burning MA in Canada Deuterium Uranium (CANDU) reactors. The fabrication of uranium-MA oxide pellets for a fast reactor blanket or MA-bearing fuel for CANDU reactors may benefit from a low-loss dedicated footprint for producing MA-spherical particles. One method for producing MA-bearing spherical particles is loading the actinide metal on a cation exchange resin. The AG-50W resin is made of sulfonic acid functional groups attached to a styrene divinylbenzene copolymer lattice (long chained hydrocarbon). The metal cation binds to the sulfur group, then during thermal decomposition in air the hydrocarbons will form gaseous species leaving behind a spherical metal-oxide particle. Process development for resin applications with radioactive materials is typically performed using surrogates. For americium and curium, a trivalent metal like neodymium can be used. Thermal decomposition of Nd-loaded resin in air has been studied by Hale. Process conditions were established for resin decomposition and the formation of Nd2O3 particles. The intermediate product compounds were described using x-ray diffraction (XRD) and wet chemistry. Leskela and Niinisto studied the decomposition of rare earth (RE) elements and found results consistent with Hale. Picart et al. demonstrated the viability of using a resin loading process for the fabrication of uranium-actinide mixed oxide microspheres for transmutation of minor actinides in a fast reactor. For effective transmutation of actinides, it will be desirable to extend the in-reactor burnup and minimize the number of recycles of used actinide materials. Longer burn times increases the chance of Fuel Clad Chemical or Mechanical Interaction (FCCI, FCMI). Sulfur is suspected of contributing to Irradiation Assisted Stress Corrosion Cracking (IASCC) thus it is necessary to maximize the removal of sulfur during decomposition of the resin. The present effort extends the previous work by quantifying the removal of sulfur during the decomposition process. Neodymium was selected as a surrogate for trivalent actinide metal cations. As described above Nd was dissolved in nitric acid solution then contacted with the AG-50W resin column. After washing the column, the Nd-resin particles are removed and dried. The Nd-resin, seen in Figure 1 prior to decomposition, is ready to be converted to Nd oxide microspheres.

437

Method for curing alkyd resin compositions by applying ionizing radiation  

International Nuclear Information System (INIS)

An alkyd resin composition is prepared by dissolving a polymerizable alkyd resin having from 10 to 50 percent of oil length into a vinyl monomer. The polymerizable alkyd resin is obtained by a half-esterification reaction of an acid anhydride having a polymerizable unsaturated group and an alkyd resin modified with conjugated unsaturated oil having at least one reactive hydroxyl group per one molecule. The alkyd resin composition thus obtained is coated on an article, and ionizing radiation is applied on the article to cure the coated film thereon. (U.S.)

438

NITRATE CONVERSION OF HB-LINE REILLEXTM HPQ RESIN  

Energy Technology Data Exchange (ETDEWEB)

Reillex{trademark} HPQ ion exchange resin is used by HB Line to remove plutonium from aqueous streams. Reillex{trademark} HPQ resin currently available from Vertellus Specialties LLC is a chloride ionic form, which can cause stress corrosion cracking in stainless steels. Therefore, HB Line Engineering requested that Savannah River National Laboratory (SRNL) convert resin from chloride form to nitrate form in the Engineering Development Laboratory (EDL). To perform this task, SRNL treated two batches of resin in 2012. The first batch of resin from Reilly Industries Batch 80302MA was initially treated at SRNL in 2001 to remove chloride. This batch of resin, nominally 30 liters, has been stored wet in carboys since that time until being retreated in 2012. The second batch of resin from Batch 23408 consisted of 50 kg of new resin purchased from Vertellus Specialties in 2012. Both batches were treated in a column designed to convert resin using downflow of 1.0 M sodium nitrate solution through the resin bed followed by rinsing with deionized water. Both batches were analyzed for chloride concentration, before and after treatment, using Neutron Activation Analysis (NAA). The resin specification [Werling, 2003] states the total chlorine and chloride concentration shall be less than 250 ppm. The resin condition for measuring this concentration is not specified; however, in service the resin would always be fully wet. Measurements in SRNL showed that changing from oven dry resin to fully wet resin, with liquid in the particle interstices but no supernatant, increases the total weight by a factor of at least three. Therefore, concentration of chlorine or chloride expressed as parts per million (ppm) decreases by a factor of three. Therefore, SRNL recommends measuring chlorine concentration on an oven dry basis, then dividing by three to estimate chloride concentration in the fully wet condition. Chloride concentration in the first batch (No.80302MA) was nearly the same before the current treatment (759 ppm dry) and after treatment (745 ppm dry or {approx}248 ppm wet). Treatment of the second batch of resin (No.23408) was very successful. Chloride concentration decreased from 120,000 ppm dry to an average of 44 ppm dry or {approx}15ppm wet, which easily passes the 250 ppm wet criterion. Per guidance from HB Line Engineering, SRNL blended Batch 80302 resin with Batch P9059 resin which had been treated previously by ResinTech to remove chloride. The chloride concentrations for the two drums of Batch P9059 were 248 ppm dry ({approx}83 ppm wet) {+-}22.8% and 583 ppm dry ({approx}194 ppm wet) {+-} 11.8%. The blended resin was packaged in five gallon buckets.

Steimke, J.; Williams, M.; Steeper, T.; Leishear, R.

2012-05-29

439

Finer mesh ion exchange resins for condensate demineralizer system  

International Nuclear Information System (INIS)

A Finer Mesh ion exchange resin technique was first introduced to the BWR condensate demineralizer system in Japan in 1985. This report outlines the various test results, improvements of equipment, and actual operational results, which were connected with introduction of the Finer Mesh ion exchange resins. A project with Finer Mesh resins was carried out to improve CRUD capturing ability and increase ion exchanging capability of condensate demineralizer systems by shifting their resin particle size distribution from conventional mesh to finer mesh by increasing resin surface areas. The condensate demineralizer system by this technique has so far proved excellent improved running performance. (author)

440

Development of radioactive spent ion exchange resin treatment technique  

International Nuclear Information System (INIS)

Spent ion exchange resins which arise in PWR type nuclear power plant are stored in tanks on site. A spent radioactive resin treatment technique has been researched and developed by this company and a by cooperative study with electric power companies. This new method utilizes a radionuclide-resin separation technique. The radionuclides are converted into inorganic stable solidified form and the resultant inactivated resin can be incinerated by the existing incinerators. Presently, actual plants are now in operation or under construction and treating stored spent resins has becomes a practical reality. (author)